Analgesia for day-case surgery

N. Rawal

Department of Anaesthesiology and Intensive Care, Örebro Medical Centre Hospital, S-701 85 Örebro, Sweden

{dagger}LMA® is the property of Intavent Limited.


    Abstract
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 Abstract
 Introduction
 Severity of pain after...
 Impact of pain after...
 Choice of anaesthetic technique...
 Day-case regional anaesthesia...
 Strategies for postoperative...
 Future perspectives in day-case...
 Conclusions
 References
 
Br J Anaesth 2001; 87: 73–87

Keywords: surgery, day-case; analgesia, postoperative


    Introduction
 Top
 Abstract
 Introduction
 Severity of pain after...
 Impact of pain after...
 Choice of anaesthetic technique...
 Day-case regional anaesthesia...
 Strategies for postoperative...
 Future perspectives in day-case...
 Conclusions
 References
 
Recent advances in anaesthetic and surgical techniques, along with escalating healthcare costs, have resulted in an ever-increasing number of surgical procedures being performed on a day-case basis world-wide. The cost-effectiveness of day-case surgery is well recognized. Day-case surgery constituted 60–70% of all surgery performed in North America in the 1990s,22 but in other parts of the world the numbers are lower. However, as outcome data become available confirming the safety of day-case surgery, it is anticipated that even more procedures will be performed on a day-case basis. Recent surgical advances include the use of endoscopic approaches for procedures such as micro-discectomy, tubal interrupt and carpal tunnel release. Major day-care surgery procedures (e.g. knee and shoulder reconstructions, laparoscopic-assisted vaginal hysterectomies, gastric fundoplications, splenectomies and adrenalectomies) are being performed at many centres. Even pulmonary lobectomy, prostatectomy, carotid endarterectomy and minor craniectomy procedures are being performed on a same-day (or 23 h admission) basis.94 Major advances in anaesthetic techniques include the use of anaesthetic agents of short duration and increasing use of regional anaesthetic techniques. It is expected that the number, diversity and complexity of operations performed in the outpatient setting will continue to increase.

Most day-case surgery procedures are associated with relatively minor surgical trauma, so discharge of these patients frequently depends on recovery from anaesthesia. Top priorities for successful outpatient surgery are the four ‘A’s: alertness, ambulation, analgesia and alimentation. Excessive fatigue, nausea, vomiting or unrelieved pain will delay discharge; these symptoms are the most common reasons for unanticipated hospital admission. Since the proportion of surgery done on an outpatient basis is increasing, and since early discharge and patient satisfaction are important goals, pain management is receiving greater attention.

Rapid recovery after the use of new, short-acting anaesthetic agents has led to the concept of fast-tracking and by-passing the post-anaesthetic care unit (PACU).5 However, the success of fast-tracking will depend to a considerable extent on effective postoperative pain management routines with simple methods such as oral analgesics. The potential cost saving of outpatient surgery may be negated by unanticipated hospital admission for poorly treated pain.30 In this review, the terms ‘ambulatory surgery’, ‘day-case surgery’ and ‘out-patient surgery’ are used synonymously to indicate that the patient is discharged on the day of surgery without overnight hospital stay.


    Severity of pain after day-case surgery
 Top
 Abstract
 Introduction
 Severity of pain after...
 Impact of pain after...
 Choice of anaesthetic technique...
 Day-case regional anaesthesia...
 Strategies for postoperative...
 Future perspectives in day-case...
 Conclusions
 References
 
The problem of postoperative pain after discharge has generally been poorly studied.22 Postoperative pain is one of the most common complaints after surgery and continues to be a challenge for anaesthetists. Contrary to the common belief that day surgery is followed by mild pain, recent studies have shown that under-treatment of pain is common. About 30–40% of discharged outpatients may suffer from moderate to severe pain during the first 24–48 h.12 74 This pain decreases with time but may be severe enough to interfere with sleep and daily functioning.29 79 Lengthy surgical procedures and certain types of operation (orthopaedic, urological, anorectal, hernia repair, breast augmentation, laparoscopic cholecystectomy, ENT, dental) tend to be associated with severe pain and therefore require more analgesia.12 43 74

As in adults, most studies of analgesia in paediatric day-case surgery have focused on the immediate postoperative course and largely ignored the risk of severe pain at home, when it becomes the responsibility of the parent.96 Studies have shown that more than half of children experience clinically significant pain after discharge.29 44 50 Despite the high frequency of under-treated postoperative pain, the overwhelming majority of patients express satisfaction with pain control.12 74 Patient satisfaction regarding postoperative analgesia is a complex issue. Satisfaction ratings are often related to psychosocial aspects of care such as communication rather than to technical aspects. Several factors may account for the low level of dissatisfaction in spite of moderate to severe pain, including poor follow-up of patients, reluctance of patients to report postoperative complications, effect of memory on recalling past experience of pain and acceptance of pain as an inevitable consequence of surgery.12


    Impact of pain after day-case surgery
 Top
 Abstract
 Introduction
 Severity of pain after...
 Impact of pain after...
 Choice of anaesthetic technique...
 Day-case regional anaesthesia...
 Strategies for postoperative...
 Future perspectives in day-case...
 Conclusions
 References
 
Severe postoperative pain causes extreme discomfort, sleep deprivation and suffering. Along with postoperative nausea and vomiting (PONV), it is the main cause of delayed discharge, contact with the hospital after discharge, unanticipated hospital admission30 and increased costs. Pain after day-case surgery may last several days and can have implications for return to work and for community health services. Currently, the majority of patients undergoing day-case surgery are healthy. However, elderly patients and those with concurrent disease are increasingly being included. The physiological effects of pain may be particularly harmful in patients with ischaemic heart disease or chronic respiratory problems.

The intensity of acute postoperative pain may be important for predicting the development of chronic pain after leg amputation, breast surgery and thoracotomy.47 In day-case surgery, chronic pain is a significant problem after open groin hernia repair; the reported incidence varies from 0 to 12%. The intensity of early postoperative pain may be an important predictor of the development of chronic pain.18

Changes in children’s behaviour have been seen after both day-case and inpatient surgery. The changes are mostly transient but in some children they persist for several weeks, months or even years. A recent multicentre survey showed a 47% incidence of problematical behavioural changes; the main predictors were age (highest incidence in children <3 years of age), pain at home and a previous difficult experience of healthcare.52 The authors emphasized the importance of effective prevention and treatment of pain. postoperative pain also seems to be a clear predictor of PONV in children.53


    Choice of anaesthetic technique and peri-operative analgesia
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 Abstract
 Introduction
 Severity of pain after...
 Impact of pain after...
 Choice of anaesthetic technique...
 Day-case regional anaesthesia...
 Strategies for postoperative...
 Future perspectives in day-case...
 Conclusions
 References
 
Safety, rapid recovery and minimal postoperative problems are essential in selecting surgical procedures and anaesthesia techniques for day-case surgery. The choice of anaesthetic technique can affect postoperative morbidity at home.53 Several new drugs have significant advantages in terms of rapid onset, excellent analgesia and amnesia, good surgical conditions and early recovery. These drugs include sedative–hypnotics such as propofol, analgesics such as remifentanil, alfentanil, ketorolac and tenoxicam, muscle relaxants such as mivacurium, rocuronium, rapacuronium and inhalational agents such as desflurane and sevoflurane. These inhalation agents provide rapid and smooth induction, quick adjustments during maintenance and rapid recovery with few side-effects.

The nature, technique, extent and duration (>90 min) of surgery and the anaesthetic technique affect the incidence of postoperative morbidity at home.22 38 53 Asking the surgeon to decompress the abdomen rigorously after laparoscopic sterilization reduces the need for postoperative opioids.24 Gas-less and abdominal wall lift techniques reduce the incidence of PONV.49 Patients undergoing laparoscopic, orthopaedic or general surgery are at a much greater risk of developing persistent symptoms. Certain drugs and anaesthetic techniques are similarly associated with a greater incidence of morbidity.38 The risk of postoperative sore throat can be reduced by using the laryngeal mask airway (LMA{dagger}) rather than endotracheal intubation.10 Succinylcholine may not be a suitable choice for day-case patients, because myalgias associated with its use may delay the resumption of normal activity. Day-case surgery patients are said to be at greater risk of succinylcholine-induced postoperative myalgia than hospitalized patients. The reported incidence of succinylcholine-induced myalgia varies among studies, from 45% to 85%. Pre-treatment with small doses of a non-depolarizing muscle relaxant before succinylcholine administration has been reported to minimize postoperative myalgia. However, despite this intervention, various incidences of myalgia, ranging from 20% to 70%, have been reported.60 In children, PONV increases, even after a single dose of morphine,93 and decreases after administration of propofol.11 The use of regional blocks57 or non-steroidal anti-inflammatory drugs (NSAIDs)59 during anaesthesia has reduced the need for postoperative opioids, so their value may be not only in improvement of pain control but also in the reduction of PONV.53

The role of opioids in day-case surgery is controversial because of their well-known side-effects, especially nausea and vomiting. At equi-analgesic doses, the emetic effects of all opioids appear to be similar. It is emphasized that pain itself is a major cause of nausea and vomiting and opioids may be anti-emetic when given to relieve pain.2 Although patients who receive an opioid are more likely to experience PONV, average recovery times are not significantly prolonged by the use of intra-operative opioids per se. Several studies have demonstrated early ambulation and discharge after fentanyl or alfentanil-based anaesthetic techniques.101 However, there is good evidence that avoidance of opioids virtually abolishes the postoperative complaints of nausea and vomiting that preclude oral intake of fluids after surgery. The ultra-short-acting opioid, remifentanil, is associated with a predictable and rapid recovery that is relatively independent of the duration of infusion. However, remifentanil has a limited role in day-case surgery because its advantages of rapid postoperative recovery and no respiratory depression are negated by the requirement for a longer-acting opioid or alternative analgesic as soon as the remifentanil infusion is stopped. To quote from a recent editorial by Leach, ‘There seems little logic in using a drug such as remifentanil intraoperatively to suppress the surgical response to painful stimulus, only to allow the patient to regain his senses, acknowledge that pain is severe and then obtund consciousness once more with large doses of a long-acting opioid’.54 Furthermore, a recent study showed that intraoperative remifentanil can cause acute opioid tolerance leading to increased postoperative pain and opioid consumption.33

With modern general anaesthetic techniques, recovery after surgery can be both rapid and complete. However, in many day-care patients, regional anaesthetic techniques might be preferable. Regional anaesthesia can reduce or avoid the hazards and discomforts of general anaesthesia, including sore throat, airway trauma and muscle pain. Regional anaesthesia, whether by epidural, spinal, peripheral nerve blocks or field block techniques, offers a number of advantages to outpatients undergoing surgery. These techniques provide analgesia without sedation, earlier discharge and prolonged postoperative analgesia. Local or regional anaesthesia can be used alone, in combination with sedation techniques or as part of balanced analgesia with general anaesthesia. Decreased requirements for opioids reduce the incidence of postoperative nausea (Table 1).


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Table 1 Advantages of local/regional anaesthesia (adapted from reference 81, with permission)
 
A controversial issue in day surgery is whether regional anaesthesia offers significant benefits over general anaesthesia for ambulatory surgery. Published data are conflicting. However, the indications for regional anaesthesia vary from one institution to another.81 All general and regional anaesthesia techniques have advantages and disadvantages. Thus, in a comparative study of spinal, epidural and propofol anaesthesia for knee arthroscopy, propofol anaesthesia was associated with shortest stay in the operating room but greatest postoperative pain and drug costs. Mepivacaine epidural block resulted in the longest stay and most prolonged postoperative analgesia. Spinal anaesthesia was the least expensive but one patient (3.3%) developed post-spinal headache.25 Acceptance of the technique by surgeon and patient, and the expertise of the anaesthesiologist, are crucial. It is essential that each unit audits its own complication rates, recovery room times and patient opinions to determine the relevance of regional or general anaesthesia. Day surgery performed under local anaesthesia is often the simplest, safest and cheapest. It is surprising how little sedation patients require if the atmosphere is conducive and the surgeon handles the tissues gently.38 81 Of particular importance is the ability of regional anaesthesia to provide a predictable intra- and postoperative course, thus aiding a smooth transition from surgery to recovery with anticipated early discharge. This is in contrast to the use of general anaesthesia with the associated risks of delayed discharge because of complications, particularly nausea, vomiting and pain. Indeed, unanticipated admission for these complications is almost exclusively a problem in patients receiving general anaesthesia.81

Regional anaesthesia does have some disadvantages (Table 2). It may take longer and it requires active co-operation of patient and surgeon. Induction may be associated with minor discomfort and there is a risk of complications specific to each block and to the local anaesthetic drug used. Furthermore, not all patients are suitable for regional anaesthesia. Difficulties in performing the block and movement during surgery can be a problem in the very anxious patient. Heavy sedation in such patients may negate the positive aspects of regional anaesthesia. If the block fails, the surgeon may be able to supplement with additional local anaesthetic and the anaesthetist must be on stand-by to convert to general anaesthesia immediately.81


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Table 2 Disadvantages of local/regional anaesthesia (adapted from reference 81, with permission)
 

    Day-case regional anaesthesia for perioperative pain
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 Abstract
 Introduction
 Severity of pain after...
 Impact of pain after...
 Choice of anaesthetic technique...
 Day-case regional anaesthesia...
 Strategies for postoperative...
 Future perspectives in day-case...
 Conclusions
 References
 
A number of regional anaesthetic techniques can be used for day-case surgery. These techniques involve little physiological trespass, compared with general anaesthesia, and so they are particularly suited to the ever-growing population of high-risk elderly patients presenting for day-case procedures. At completion of surgery, infiltration of the wound using a long-acting local anaesthetic (e.g. 0.25% bupivacaine) provides prolonged postoperative analgesia. For ocular surgery, peribulbar, retrobulbar or topical blocks can be performed safely, effectively and with few complications.

In children, the use of regional anaesthesia techniques before the start of surgery (but after the child has been put to sleep) will reduce the requirements for general anaesthetic drugs during surgery, which may result in a more rapid recovery, less nausea and vomiting, and earlier alimentation and discharge. Caudal block is easy to perform and provides excellent analgesia for perineal or inguinal surgery. Sympathetic effects on the circulatory system are rare. Blocks may be performed on the ilioinguinal nerve, iliohypogastric nerve, the dorsal nerve of the penis, the brachial plexus, femoral nerve or digital nerves. Ring blocks of the wrist or ankle and local infiltration are simple and effective.

Intravenous regional anaesthesia
Intravenous regional anaesthesia (IVRA) is one of the most common regional techniques world-wide.37 69 It is very easy to perform: the only technical skill necessary is the ability to perform venipuncture (although skill in resuscitation is also required if complications occur). IVRA is most suitable for short duration (<45–60 min) surgical procedures in distal extremities (forearm, hand, ankle and foot). Good surgical anaesthesia can be achieved rapidly after the injection of local anaesthetic and recovery is fast after the release of the tourniquet. No other regional anaesthetic technique provides such a control over the onset, duration and recovery of block. The published success rates range from 94% to 100%. Adjuvants such as opioids, NSAIDs and muscle relaxants have been used to improve the quality of block and postoperative analgesia, but the results are generally unimpressive. The main problems of the technique are related to the requirement for a tourniquet, and include restricted area of anaesthesia, pain associated with the tourniquet, and risk of local anaesthetic toxicity due to accidental release of the tourniquet. Some recent studies suggest that the use of ropivacaine may provide prolonged postoperative analgesia.8 21 Although ropivacaine is less toxic than bupivacaine, its use is not recommended for IVRA because it is much more toxic than the commonly used prilocaine and chloroprocaine.37 72

Peripheral nerve blocks
Peripheral nerve blocks provide excellent analgesia over a limited field and with minimal systemic effects. The blocks are generally easy to perform, inexpensive and very safe. Peripheral blocks are possible for nearly all kinds of surgery (Figure 1). Even in situations where the block is ineffective for surgery, the catheter can often be used for postoperative pain management. The technique is under-used both for surgery and for postoperative pain treatment. Peripheral nerve blocks have extended the indications for day-case surgical procedures such as major shoulder surgery and knee reconstruction. Comparative studies of interscalene block and general anaesthesia for day-case shoulder arthroscopic surgery showed that 8% of the patients receiving general anaesthesia required unanticipated admission compared with none in the patients receiving interscalene block.17 26 Details about different blocks and techniques are beyond the scope of this review; they can be found in standard books.



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Fig 1 Possible peripheral nerve blocks for surgery and postoperative analgesia.

 
Upper extremity blocks for day surgery
Several techniques are available to provide efficient regional anaesthesia of the upper limb for day-case surgery. The technique chosen should be appropriate for the intended surgery. The timing of the block is important. It is not advisable to squander operation-room time on waiting for the block to work. Special block rooms outside the operating rooms should be available to (i) handle the high volumes and rapid turnover of patients; (ii) perform the blocks well in advance of the scheduled surgery allowing sufficient ‘soak time’ (>=20 min) for the local anaesthetic to work; and (iii) recognize early any technical failure so that the decision to proceed with rescue block or general anaesthesia can be made quickly once the patient arrives in the operating room. The block should have residual analgesia in the postoperative period, minimizing the need for systemic analgesics. The limb with residual motor block should be protected appropriately until complete resolution of the block. Criteria for fast-track discharge should be established to minimize patient’s recovery and discharge times. In some institutions, patients are allowed to leave before regression or resolution of the block. A telephone follow-up the next day monitors patient satisfaction and any post-surgical complications.62 During surgery, a tranquil environment should be provided for the patient by allowing them to watch a video, listen to music, or sleep lightly, with judicious use of midazolam if necessary.

Many techniques are available to block the brachial plexus; the most commonly used are interscalene block for shoulder surgery, supraclavicular or interscalene block for upper arm surgery, axillary or intraclavicular block for elbow or forearm surgery and axillary or peripheral nerve block for wrist and hand surgery. The medial, ulnar and radial nerves may be blocked using consistent anatomic landmarks at the elbow or wrist and small volumes of local anaesthetic.

Peripheral nerve blockade can also be used to supplement patchy brachial plexus anaesthesia or provide anaesthesia to a specific site in which surgery is limited and of short duration.

Both bupivacaine and ropivacaine appear to be as efficacious as long-acting local anaesthetics for brachial plexus block.48 Opioid and non-opioid adjuncts have been added to local anaesthetic solutions in an attempt to improve or prolong analgesia during brachial plexus blockade. Although several studies have reported that analgesia lasts longer when opioids such as morphine, sufentanil and buprenorphine are added to local anaesthetic, other studies found no advantages.62 Clonidine 0.5 µg kg–1 is reported to prolong anaesthesia and analgesia, but higher doses (e.g. 300 µg) can cause sedation and hypotension, both of which are undesirable in day-surgery patients.14

Lower extremity blocks for day surgery
A combined block of the lower extremity offers many advantages over spinal or epidural anaesthesia, such as less hypotension, no urinary retention or post-spinal headache, and fewer concerns regarding bleeding risk in patients taking anticoagulants. For knee surgery, the extent of sensory and motor blockade achieved with a combination of a sciatic and a dorsal lumbar plexus nerve block is comparable to that achieved with a central nerve block. For surgery below the knee, popliteal sciatic nerve block alone or combined with a saphenous nerve block is a reasonable choice; for foot surgery an ankle block is probably the best method. The choice of local anaesthetic depends on duration of the surgery, but attention should be paid to the possibility of systemic toxicity because combined proximal nerve blocks of the lower extremity frequently require doses that are close to the maximum recommended doses. The arguments against peripheral nerve blocks are that they take longer, it is impossible to block all nerves of the lower extremity from one injection site, and there is a certain proportion of failed blocks, even in experienced hands. However, acceptance of peripheral blocks by patient (and surgeon) can be increased by selection of appropriate blocks, patient education and follow-up routines.31

Intra-articular analgesia
Intra-articular drug administration has gained popularity because of its simplicity and efficacy in achieving anaesthesia for diagnostic and operative arthroscopy and for providing postoperative analgesia. Although the knee joint has been examined most commonly, arthroscopy of other joints such as shoulder, ankle, wrist, metatarsophalyngeal and temporomandibular joints is being increasingly practised.27 Intra-articular instillation of local anaesthesia during arthroscopic procedures has been used by many orthopaedic surgeons to provide pain relief after surgery. However, there are conflicting reports in the literature about its therapeutic role. A systematic review of 20 controlled trials with data from about 900 patients showed evidence for a postoperative analgesic effect in 12 of the 20 studies of intra-articular administration of local anaesthetic following arthroscopic knee surgery. However, the evidence was not compelling and, in most cases, analgesia was short lived. Nevertheless, the authors concluded that the technique may be of clinical significance in day-case surgery.61 The use of intra-articular morphine is effective in the management of pain after arthroscopic knee surgery86 and anterior cruciate ligament repair.45 A systematic review of 36 randomised control trials showed that intra-articular morphine may have some effect in reducing postoperative pain intensity and consumption of analgesics.46 However, most of the studies had significant problems in design, data collection and statistical analysis. The authors emphasized the need for better methodological quality trials to decide conclusively if intra-articular morphine analgesia is clinically useful. There is some evidence that intra-articular NSAIDs have a clinically relevant peripheral analgesic action.83 Current evidence suggests that intra-articular multimodal regimens may provide improved effects on postoperative pain and convalescence.10 34 83

Central neural blockade: epidural, spinal or combined spinal epidural?
Spinal and epidural anaesthesia are effective alternatives to general anaesthesia in ambulatory surgery, with some investigators demonstrating advantages of fewer side-effects and earlier discharge times. However, this remains a controversial issue, as some clinicians are concerned about delayed patient recovery. Selection of short-acting local anaesthetic drugs is therefore appropriate. Combinations of local anaesthetics, short-acting opioids and non-opioids may be used to allow lowest possible effective dose of local anaesthetic to provide early postoperative ambulation and discharge.

The choice of a central block depends on patient request, surgical considerations and anaesthetic benefits. For surgical procedures with patients lying face down, there may be a problem with airway control and general anaesthesia unless endotracheal intubation is used. Anaesthetic benefits with central blocks are most evident in the postoperative phase. The patient may be wheeled out immediately after surgery. Residual block protects the patient from initial pain and there is some evidence that regional anaesthesia also protects the patient from pain after the block has worn off. Patients are in less need of postoperative opioids for pain relief and there is less tendency for nausea or vomiting after central blocks.32 68 This is a major benefit in day-case surgery, both in terms of better patient comfort and faster discharge. The risk of major neurological complications is very small. However, the patient should be informed about the symptoms of epidural haematoma or abscess formation, because these complications have been reported after discharge of day patients.67 68

Epidural anaesthesia with a short-acting local anaesthetic such as lidocaine provides about 60–90 min of anaesthesia with possible discharge 4–6 h after the block. However, it has some drawbacks. It is more time consuming to perform and there is a delay in onset of block. Ræder describes a technique aimed at reducing the time required to achieve an adequate epidural block: the total dose of local anaesthetic is injected as a bolus into the epidural needle, the test dose is eliminated and the surgical site prepared before the block is evident.68

Spinal anaesthesia is the most common central block in a day-surgery setting. Spinal block has distinct advantages over epidural anaesthesia, with less time required to achieve an adequate block, lower incidence of incomplete sensory and motor block and pain during surgery.81

The spinal technique is easy to perform and has a very high success rate and an enviable safety record.9 The out-patient spinal anaesthetic is typically of rapid onset, predictable duration, minimal side-effects and reliable offset.39 Spinal anaesthesia provides excellent surgical conditions for orthopaedic surgery on lower extremities, for gynaecological, urological and perirectal procedures and for lower abdominal procedures such as inguinal hernia. A 17-nation European survey of 105 hospitals showed that almost 40% of all ambulatory surgery in the participating hospitals was performed under regional blocks. Spinal and epidural blocks were used in 25–30% of hospitals. However, there was a great difference between European countries: these blocks were well accepted in Scandinavian countries, Germany and Switzerland, whereas Austria, Greece and Ireland restricted the use of these blocks in day-case surgery.69 A recent Swedish survey showed that spinal block was used routinely in 85% and epidural block in 28% of the 109 day surgery units in the country (Rawal N, unpublished data).

Lidocaine is used most frequently, though recent studies have shown that transient neurological symptoms (TNS) can occur in 16–40% of outpatients.35 56 66 Alternative local anaesthetic drugs such as bupivacaine in small doses (5–10 mg) and ropivacaine are associated with a very low incidence of TNS but are not always appropriate for day-case surgery.39 Adjuvants such as fentanyl 10 µg can improve the success rate of low-dose hyperbaric bupivacaine (e.g. 5 mg) spinal anaesthesia without prolonging discharge time.13 TNS should be taken into account when considering the choice of local anaesthetic, especially when the lithotomy position or knee arthroscopy is planned.39 In a recent study, mepivacaine 60–80 mg was shown to be a suitable anaesthetic choice for ambulatory spinal anaesthesia with respect to anaesthetic, as well as recovery profiles. A postoperative follow-up did not show TNS in any of the 60 patients who received spinal mepivacaine as part of combined spinal–epidural (CSE) for anterior cruciate ligament repair.64

A former barrier to outpatient spinal administration, namely post-dural puncture headache, has been largely eliminated with the introduction of conical-tipped needles that result in less dural trauma. Comparative studies of spinal and general anaesthesia have dispelled the myth that spinal anaesthesia results in operating room inefficiency. Novel manipulations of baricity and dose have resulted in significant reductions in unwanted motor block using conventional spinal anaesthesia.39 66

For surgical procedures involving one lower limb, a unilateral spinal block has been shown to minimize the haemodynamic effects of spinal anaesthesia. The technique involves the lateral decubitus position, low-dose hyperbaric local anaesthetic solution, low speed of intrathecal injection and directional pencil-point spinal needles.19 Unilateral spinal block for ambulatory surgery needs further evaluation.

Selective spinal anaesthesia (SSA) using lower doses of intrathecal agents with or without intrathecal or systemic adjuvants has been used to provide spinal anaesthesia with greater selectivity and rapid return of function. It has been demonstrated that SSA provides pinprick analgesia suitable for surgery while light touch, proprioception, motor and sympathetic function are preserved.91

CSE anaesthesia combines the rapidity, density and reliability of subarachnoid block with the flexibility of continuous epidural block.77 Although, at first sight, CSE techniques appear to be more complicated than epidural or spinal block alone, intrathecal drug administration and siting of the epidural catheter are both enhanced by the combined, single-space, needle-through-needle method. CSE is an effective way to reduce the total drug dosage required for anaesthesia and analgesia, thus making a truly selective blockade possible.77 In contrast with epidural anaesthesia, the other leading central neuraxial technique, CSE, has a lower failure rate and a faster onset time.40 The practicality of CSE has been questioned. CSE is well-established for inpatient surgery and obstetrics but is still in its infancy in day-case surgery. By providing the ‘safety net’ of an epidural catheter, CSE allows use of the lowest effective dose of local anaesthetic.65 90 For ambulatory knee surgery, CSE allowed Urmey and colleagues to reduce the dose of spinal lidocaine from 80 mg to 40 mg.90 Similarly, Pawlowski and others used CSE to identify appropriate doses of spinal mepivacaine in order to eliminate the risk of TNS.64 The security of an epidural catheter allows minimal dosing of local anaesthetic and therefore more precise predictability of day surgery spinal anaesthesia.


    Strategies for postoperative pain management
 Top
 Abstract
 Introduction
 Severity of pain after...
 Impact of pain after...
 Choice of anaesthetic technique...
 Day-case regional anaesthesia...
 Strategies for postoperative...
 Future perspectives in day-case...
 Conclusions
 References
 
Optimal postoperative pain control for day-case surgery should be effective and safe, produce minimal side-effects, facilitate recovery and be easily managed by patients at home. Analgesic techniques should permit ‘normal’ activities and additional analgesic supplements should be provided to cover any painful activity. Rescue analgesia should be provided if the prescribed analgesic is ineffective. The use of pre-packaged take-home analgesics specific to the type of surgery and breakthrough medication can lead to improved pain control, mobility and sleep.58

Pain assessment and documentation
Pain intensity must be assessed and reassessed frequently and documented on the bedside chart (‘making pain visible’). The day-care facility should define a maximum acceptable pain score and train the personnel to treat pain promptly if it exceeds a certain level. At our institution, a hospital-wide policy of keeping pain levels at <=3 on the 10-point visual analogue scale (VAS) has been functioning satisfactorily since 1991 for surgical day-case and inpatients. Pain intensity is assessed and documented every 3 h for inpatients and at least every hour for day-case surgery patients.71 It is important to assess pain and efficacy of analgesia at rest and during activity. A practical scheme is to assess pain at rest in early recovery, and at rest and during activity at and after discharge. In situations where communication is difficult, a verbal or observer (nurse) scoring system can be used82 (Figure 2). It may be difficult to determine whether small children are in pain after surgery because such children are unable to express their feelings in words. If a child’s pain is treated at home, parents have to estimate the level of pain and therefore need to be informed appropriately. Pain assessment tools have been formulated and validated for parents to use at home.20 95 Documenta tion of pain scores also allows the day surgery unit (DSU) to perform regular audits to confirm that pain management techniques are not causing problems at home.



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Fig 2 Pain scoring systems (modified from reference 82).

 
Pain management in the PACU
postoperative pain control should be started intra-operatively by supplementing general anaesthesia with short-acting opioids, NSAIDs or regional anaesthesia. This should aid smooth recovery. When opioids are used in the recovery period, rapid and short-acting drugs such as fentanyl and alfentanil should be administered i.v. and titrated to desired effect.

Regional analgesia performed in conjunction with general anaesthesia is becoming an increasingly important component of paediatric postoperative pain management. A variety of regional blocks can be performed simply and quickly in paediatric day-surgery patients.

The possible differences in PONV between different opioids have not been demonstrated in controlled trials: no difference in adverse effects was noted between morphine, pethidine (meperidine) and fentanyl (in adults) using PCA97 or between i.v. morphine and i.v. fentanyl in the PACU.23 Incidence of nausea and vomiting increases significantly in the period after discharge, because morphine can act as an emetic stimulus on the trip home, resulting in delayed vomiting. Discharge may also be delayed by PONV and sedation. Combinations of analgesics that act by different mechanisms result in additive or synergistic analgesia, allowing total doses of drugs to be reduced and so reducing side-effects. Such techniques, using a combination of opioid, NSAID, paracetamol and local anaesthetic, are superior to any single modality. Regular and frequent assessment of pain intensity is important. Differences between analgesic methods may only become evident when pain is assessed during activity, so pain should be assessed both at rest and during activity.82

Choice of analgesic after discharge
Oral analgesics are the mainstay of continuing pain control at home, and it is important to encourage patients to take analgesics pre-emptively and regularly, starting before the effect of the local anaesthetic has worn off.81 For mild pain, simple analgesics such as paracetamol may be sufficient. Patients with mild to moderate pain in day surgery benefit from combinations of NSAIDs and weak opioids in addition to regional or local anaesthesia. Patients’ responses to drugs vary, so rescue analgesia for postoperative pain beyond acceptable levels may be needed. Strong opioids are generally avoided because of their well-known side-effects, including the risk of respiratory depression.

Paracetamol is the most commonly used analgesic world-wide because it is effective, cheap and safe. It is often combined with other drugs, such as weak opioids and NSAIDs, as part of a balanced analgesic approach. The effectiveness of paracetamol is often underestimated because this drug is often not administered correctly. Paracetamol has a dose-related potency for postoperative pain in paediatric surgery.51 Earlier dosing with paracetamol 10–15 mg kg–1 ‘as necessary’ failed to provide therapeutic plasma concentrations and so was ineffective.96 In children, a loading dose of 40 mg kg–1 (or greater) is currently recommended followed by regular dosing of 90 mg kg–1 day–1 to maintain therapeutic plasma concentrations.3 96 98

The currently recommended doses for rectal and oral administration of paracetamol are the same. However, the rectal dose should be higher than the oral dose, because of poor and erratic absorption of paracetamol from suppositories.3 51

Weak opioids, such as codeine and dextropropoxyphene, are the most commonly used oral opioids, usually in combination with paracetamol. Tramadol is believed to have a potency equal to that of pethidine28 without causing significant respiratory depression. Its main drawback is a high incidence of nausea and vomiting. Our recent controlled comparison between tramadol, metamizol and paracetamol in patients undergoing day-case hand surgery showed that none of the study drugs provided effective analgesia in all patients. The percentage of patients who required rescue dextropropoxyphene at home was 42% with paracetamol, 31% with metamizol and 23% with tramadol. However, tramadol was associated with the greatest frequency and severity of adverse effects such as nausea and dizziness and, consequently, with the greatest dissatisfaction. Metamizol and paracetamol provided good analgesia in 70% and 60% of the patients, respectively, with low incidence of side-effects.78

NSAIDs are now the basis of most day-surgery analgesic regimes. As well as providing effective analgesia, their anti-inflammatory effects may help reduce local oedema and minimize the use of more potent drugs and their accompanying side-effects. Several advantages are offered by NSAIDs in the peri-operative period. They are effective as the sole analgesic in a high proportion of cases of mild to moderate pain. When combined with opioids, they can enhance the quality of opioid-based analgesia and often diminish opioid requirements by about 25%. Some studies have shown that they may reduce opioid-related side effects.

NSAIDs are frequently used to treat mild to moderate pain and as a component of multimodal regimens for moderate to severe pain. In 1998, the Royal College of Anaesthetists issued guidelines for the use of NSAIDs in the peri-operative period. Based on the strongest evidence available, it is stated that ‘In situations where there are no contraindications, NSAIDs are the drug of choice after many day-case procedures.’80 However, controversy still surrounds the use of NSAIDs because of their significant gastrointestinal, haematological and renal side effects. Systematic reviews have not found any important differences between different NSAIDs but have found differences in toxicity related to increased doses and possibly to the NSAID itself. It has been proposed that the anti-inflammatory properties of NSAIDs are mediated through cycloxygenase 2 (COX-2) inhibition, whereas adverse effects occur as a result of their effects on COX-1. The World Health Organization has categorized COX-2-selective drugs as a new subclass of NSAIDs (coxibs). The two coxibs currently available, rofecoxib and celecoxib, appear to be as effective as non-selective NSAIDs in suppressing inflammation and providing analgesia, while reducing the incidence of endoscopy-verified ulcers to levels similar to those seen with placebo.55 Parecoxib is a new COX-2-specific agent that is given i.v. or i.m. The role of COX-2-specific NSAIDs in postoperative pain management will become clearer when the results of ongoing clinical trials become available. Overall, the benefits of NSAIDs greatly outweigh their risks. Choice of drug will depend on availability, desired route of administration (oral, rectal, i.v.), duration of analgesia and cost.

In general, there is a great need for powerful non-opioid analgesics in future day surgery and they may either be prescribed alone or be used to reduce opioid requirements. It may prove more convenient and less unpleasant to give these drugs by the i.v. route rather than by i.m. or rectal administration.

Regional techniques at home
Administration of local anaesthetic into the surgical wound is effective and safe but the analgesia lasts only a few hours. We have described a technique using an elastometric balloon pump, which allows the patient to self-administer local anaesthetic analgesia at home.75 The technique involves placement of a multihole, thin (22-gauge) epidural or Perifix brachial plexus catheter (B. Braun, Melsungen, Germany) subcutaneously into the surgical wound, subacromially, intra-articularly or in the axillary brachial plexus sheath (depending on the surgical site). The catheter is tunnelled 4–5 cm subcutaneously by the surgeon and firmly secured on to the skin by sterile tape. Axillary brachial plexus catheters are placed and secured in position by anaesthetists. The catheters are introduced 3–5 cm within the sheath and secured to the skin with transparent dressing and tape.

Using aseptic technique, the catheters are connected to a 50 or 100 ml elastomeric (balloon) pump (Figure 3) with the appropriate concentration and volume of local anaesthetic drug (‘Home Pump’; I-Flow Corporation Lake Forest, CA, USA). The balloon pump is filled with a volume of local anaesthetic to provide 10 doses for postoperative pain management. After the operation, when the patient feels pain, he starts the local anaesthetic infusion by opening the clamp. The patient stops the infusion by closing the clamp after the prescribed time (usually 6 min), or earlier if he is satisfied with pain relief (Figure 3). When the patient no longer requires analgesia, he removes the tape, pulls out the catheter and discards the pump. In most cases, the patient gives himself the first dose in the PACU.



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Fig 3 Self-administration of local anaesthetic solution by a patient. On opening the clamp (left), the solution starts running into the catheter. After the prescribed time (usually 6 min), the patient closes the clamp (confirmed by a clicking sound) to stop the infusion (right). The patient is encouraged to use a timer as a reminder to close the clamp. (Reprinted from reference 73 with permission from Lippincott–Williams and Wilkins.)

 
In brachial plexus catheters, 0.125% bupivacaine or ropivacaine was used, whereas 0.25% was used in all other catheters. The 0.125% solution was used to reduce or avoid the risk of possible injury caused by excessive motor block. The maximum volume of local anaesthetic allowed for each administration was 2.5 ml for maxillofacial surgery, 5–10 ml for surgical wounds and 10 ml for other procedures. An appropriately sized pump (50 or 100 ml) filled with local anaesthetic to provide 10 doses at home was given to the patient before discharge. The patient was told not to use the pump more than once an hour. Follow-up consisted of evaluation of pain relief at home, pump function, use of rescue medication and overall satisfaction or dissatisfaction with the technique.

Pain relief was graded as good to excellent by 90% of patients. Onset of analgesia was experienced within 5 min, and the duration of analgesia after each administration of local anaesthetic varied from 2 to 8 h. Patient follow-up did not reveal any infection or any other major problem with the technique, and patient satisfaction was very high. Nearly 700 patients undergoing a variety of surgical procedures have been treated with patient-controlled regional anaesthesia (PCRA) at our hospital without any major complications.

Recent controlled trials have demonstrated the efficacy and safety of incisional catheter PCRA in patients undergoing Caesarean section,100 abdominal hysterectomy99 and inguinal hernia repair.92 Our controlled comparison between 0.125% ropivacaine and 0.125% bupivacaine for axillary brachial plexus PCRA at home demonstrated the feasibility, efficacy and safety of this technique for treating pain outside the hospital. Both drugs provided effective analgesia, but patient satisfaction was better with ropivacaine PCRA.76 White cell counts, bacterial culture of the catheter tips and wound inspection have not shown any evidence of infection.92 99

The main concern with the balloon pump device is the risk of local anaesthetic toxicity if the patient neglects to close the clamp. This can be prevented with newer devices which allow a continuous infusion of local anaesthetic at a pre-set rate. For example a 100 ml elastomeric pump (‘Pain Buster’; I-Flow Corporation, Lake Forest, CA, USA) can provide adequate analgesia at home for 2 days when the local anaesthetic is infused at a rate of 2 m h–1. However, this is not PCRA. Newer, lightweight pumps with appropriate safety features including lock-out possibilities and disposable cassettes for local anaesthetic solutions are also available to provide safe PCRA in the patients’ home environment (Microject; Sorensen Medical, UT, USA). Further studies are necessary to establish the efficacy and safety of this promising new technique at home after ambulatory surgery. Studies are also necessary to evaluate the optimal concentration and volume of local anaesthetic and the possible role of adjuvant drugs. Adequate patient information is important (Table 3).


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Table 3 Patient instructions for post-operative PCRA at home
 
Role of patient (and parent) information
Preoperative preparation of patients
Postoperative pain is often associated with anxiety; it has been demonstrated that patient education and preoperative preparation can reduce postoperative pain.36 Successful postoperative pain control depends on the knowledge and demands of the patient. A questionnaire survey for evaluating the general public’s perception of postoperative pain revealed that almost half of patients were prepared to suffer pain rather than complain.84 Patients should be informed about the need to treat pain and about the various ways of managing pain. The information should be given verbally and in writing. Day patients with severe pain at home do not always take their medication as prescribed and may even mix in their own analgesics. Clear instructions are therefore mandatory. On admission to DSU, pain management should be discussed with the patient and the pain assessment scoring explained. Patient preferences, for example with regard to the use of suppositories or central neuraxial blocks, should be respected.

Analgesia needs to be tailored to the severity of pain associated with the procedure. Drugs are chosen on the basis of their availability, freedom from side-effects, convenience of administration and safety. Patients’ responses to drugs vary, so rescue analgesia for pain beyond acceptable levels may be needed. Pre-packaged analgesics should be provided for anticipated mild, moderate or severe pain. A follow-up call the next day reassures the patient and provides feedback about analgesic efficacy. Regular audit of the postoperative pain service is essential.82

For patients undergoing surgery with regional anaesthetic techniques, patient education during the pre-operative clinic visit is essential to improve patient acceptance of the use of regional anaesthesia. Audiovisual material and an information pamphlet are helpful tools, giving patients time to make an intelligent decision and to be psychologically prepared for the block. Patient education will also help to allay apprehension about being awake during the surgery and to address the fear of pain during block.

Local anaesthetics such as bupivacaine should be chosen for their long-lasting effect. All surgeons should be encouraged to use bupivacaine for wound infiltration. However, patients should be warned that the effects will wear off and that they should take another analgesic before this happens, particularly before going to bed on the first night after surgery. Patients must meet standard discharge criteria following day surgery with local or regional anaesthesia. Patients who have undergone central neural blockade should have return of motor and sensory function and preferably void before discharge. Those who have residual numbness after limb anaesthesia should be advised about limb protection17 (Table 4).


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Table 4 Day-case surgery: infomation given before discharge
 
Prevention and treatment of pain and PONV at home remain a challenge in children undergoing day-case surgery. The parents of a child recovering at home have to estimate the intensity of pain and treat postoperative pain. A general instruction to parents to give the child some medication for pain at home as needed is not enough. To ensure successful pain management at home, it is important to give parents appropriate information. It is also important to train doctors and nurses to provide proper information on treating pain and to determine the outcomes of training programmes. Since hospital personnel often recommend over-the-counter pain medicines, we should also direct attention to pharmacists’ knowledge of pain treatment in children and their ability to provide information for parents. Staff training programmes to provide adequate information about postoperative pain medication for the parents can be highly beneficial.85


    Future perspectives in day-case surgery and pain management
 Top
 Abstract
 Introduction
 Severity of pain after...
 Impact of pain after...
 Choice of anaesthetic technique...
 Day-case regional anaesthesia...
 Strategies for postoperative...
 Future perspectives in day-case...
 Conclusions
 References
 
Advances in day-case anaesthesia and development of minimally invasive surgical techniques can be expected to continue. Day-case surgery has presented a new set of challenges and goals for the anaesthetist. Newer inhalational agents and improved anaesthetic drugs with minimal emetic sequelae and new drug delivery techniques may improve the outcome of day-case surgery in the future. Widespread use of improved sedation and regional anaesthesia will also evolve. Further development of target infusion anaesthesia will smooth the maintenance of day-case anaesthesia.15 Although the requirement for alternative analgesia immediately after cessation of infusion limits the usefulness of remifentanil in day-case surgery, further advances in opioid therapy may become available with the introduction of trefentanil and mirfentanil. The former has characteristics intermediate between those of alfentanil and remifentanil.16 63 Patient-controlled approaches to newer opioid drug delivery systems, such as transdermal iontopheresis7 or intranasal87 or transmucosal6 delivery also need to be evaluated for their suitability and safety in patients discharged after day-case surgery. Based on current trends, it is fair to predict an increased use of local or regional anaesthesia alone, in combination with sedation anaesthesia or as part of a multimodal technique with general anaesthesia. As more extensive and painful procedures, such as cholecystectomy, knee reconstructions, shoulder procedures, hysterectomy and laminectomy, are being performed as day surgery, there will be a pressing need to introduce far better drugs to alleviate PONV and pain.

Spinal and epidural blockade are widely practised in several countries. Discharge times of 2–3 h after short-acting local anaesthetics or low-dose local anaesthetic drug combinations are not unrealistic.30 Patient acceptance will increase if the benefits of these procedures are explained by enthusiastic surgeons and anaesthetists. It is no longer valid to oppose spinal anaesthesia on account of post-lumbar puncture headache. This may be reduced to less than 1% by the use of 26- or 27-gauge pencil-point spinal needles.39 Further improvements in needle and catheter technology will make central neuraxial blocks safer. The trend towards increasing use of peripheral nerve blocks42 will accelerate as newer catheter systems (e.g. Stim-Kath, Epimed) become available which allow successful placement by nerve stimulation technique.1 The recent introduction of less toxic long-acting local anaesthetics ropivacaine and levobupivacaine have improved the safety of regional techniques. A variety of opioid and non-opioid adjuvants to local anaesthetic drugs are under investigation. Other future directions in the use of regional anaesthesia for day-case surgery include the development of local anaesthetic encapsulated in lipophilic membranes, which allows sustained release of local anaesthetic and thus prolonged analgesia lasting several days after single injection techniques.

Although the concept of fast-tracking is well accepted in day-case surgery, the issue of at-home recovery is generally neglected. Almost all literature concerns the early postoperative period while the patient is in hospital. At-home recovery and return to normal daily activities are of greater interest to the patient, his family and society. The following questions need to be addressed. What is the natural course of recovery after different surgical procedures? When is cognitive function restored to baseline? When do patients resume usual at-home activities? What is the relationship between hospital costs and costs to society?


    Conclusions
 Top
 Abstract
 Introduction
 Severity of pain after...
 Impact of pain after...
 Choice of anaesthetic technique...
 Day-case regional anaesthesia...
 Strategies for postoperative...
 Future perspectives in day-case...
 Conclusions
 References
 
Day surgery is a cost-effective, quality approach to surgery that has expanded rapidly in recent years. Multiple factors have contributed to this transition, including economic forces, improved anaesthetic and surgical techniques, better pre-operative planning, better patient education and an enhanced ability to deliver adequate analgesia in the outpatient setting. Many procedures that used to be performed on an in-patient basis under general anaesthesia are now performed on a day basis under local or regional anaesthesia alone or combined with sedation techniques.

Regional anaesthesia offers many advantages for the day-case surgery patient. Patients can remain alert and, with proper techniques and agents, are able to be rapidly discharged with minimal side-effects and optimal pain control. Local and regional anaesthesia, alone or as part of general anaesthetic technique, offer major benefits to the ambulatory surgery patient. In general, peripheral nerve blocks are under-used for ambulatory surgery. The use of regional techniques will depend on local tradition, the day-surgery facility, patient and surgeon co-operation and skill of the anaesthetists. In many institutions, neuraxial blocks such as epidural, spinal, and CSE are controversial regional techniques for day-case surgery. However, by appropriate patient selection, choice of equipment, drugs and adjuvants, the anaesthetist can tailor neuraxial blocks to a specific type and duration of surgery.

The success of day-case surgery depends, to a large extent, on both effective control of postoperative pain and minimization of side-effects such as sedation, nausea and vomiting. Inadequate analgesia after surgery is a problem: it has been demonstrated that one-third of patients suffer moderate to severe postoperative pain as a result of inadequate analgesia. Under-treatment is still one of the most common errors in the treatment of pain in children. Day-surgery analgesia must allow the patient to be discharged safely and without delay. Additionally, after the patient has been discharged, he must not require close medical or nursing supervision, either for the administration of analgesia or for safety reasons. Side-effects that might be regarded as minor in the inpatient may contribute to unexpected admissions in the day-case setting. Prolonged recovery may disrupt patient flow and increase institutional costs per patient. The unplanned overnight hospital admission rate may well reflect the quality of care in day-case surgery.

The growth of day-case surgery requires both a rapid return to street fitness and the provision of analgesia appropriate to the nature of the surgery undertaken. Balanced analgesia in day-case surgery commonly involves intra-operative administration of short-acting opioids such as fentanyl, and wound infiltration with local anaesthetic at the end of surgery supplemented in the postoperative period by an oral, non-opioid analgesic. Recent improvements in our pharmacological knowledge concerning pain medication have made it possible to provide more individualized pain treatment for adults and children.

Dispensing appropriate analgesia with clear instructions for the patient is crucial. Giving patients pre-packed analgesics for anticipated mild, moderate or severe pain, with clear directions has the potential for improving patient comfort at home. After discharge, patient follow-up is essential to monitor effectiveness of pain treatment. Day-surgery units should standardize and audit their analgesic treatments for mild, moderate and severe pain. New portable PCRA systems are becoming available which can provide effective and safe analgesia at home for several days. Small disposable pumps, pre-loaded with local anaesthetic, with pre-set hourly infusion rates or self-administered bolus infusions provide effective analgesia at home.


    References
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 Abstract
 Introduction
 Severity of pain after...
 Impact of pain after...
 Choice of anaesthetic technique...
 Day-case regional anaesthesia...
 Strategies for postoperative...
 Future perspectives in day-case...
 Conclusions
 References
 
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