Right thoracic paravertebral analgesia for hepatectomy

A. M.-H. Ho*, M. K. Karmakar, M. Cheung and G. C. S. Lam

Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, People's Republic of China

* Corresponding author. E-mail: hoamh{at}cuhk.edu.hk

Accepted for publication April 28, 2004.


    Abstract
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 Abstract
 Introduction
 Case reports
 Discussion
 References
 
Haemostatic deficiencies, common among cirrhotic patients, may deteriorate further after hepatectomy, increasing the bleeding risk associated with the use of thoracic epidural analgesia. We describe two patients who enjoyed immediate post-operative tracheal extubation and satisfactory analgesia using mainly right thoracic paravertebral analgesia after right lobe hepatectomy.

Keywords: analgesia ; anaesthesia, regional ; anaesthetics, local ; complications, coagulopathy ; complications, thrombocytopenia


    Introduction
 Top
 Abstract
 Introduction
 Case reports
 Discussion
 References
 
Hepatocellular carcinoma affects more than 500 000 people globally each year.1 Over 75% of hepatocellular carcinomas are caused by persistent hepatitis B or C.1 Some patients undergoing hepatectomy also suffer from hepatitis-induced cirrhosis, decreased hepatocyte mass and coagulopathy. During and after surgery, further loss of liver mass and possibly intra-operative liver ischaemia, often lead to an initial decline in coagulation function, typically at its worst level on the first-to-second post-operative day.24 In addition, thrombocytopenia may be present as a result of portal hypertension, reduced plasma thrombopoietin, or both.5 6 Coagulopathy and thrombocytopenia may be contraindications to central neuraxial blockade. Although many hepatectomy patients could be managed after surgery in a high dependency unit with parental analgesics such as patient-controlled morphine,7 some would benefit from more intense forms of analgesia with minimal central nervous system depression. Recently, in an effort to reduce post-hepatectomy intensive care needs and to improve patient comfort, we began exploring the use in hepatectomy patients of thoracic paravertebral analgesia, a technique already used extensively in our centre for surgery involving the chest and upper abdomen. Compared with epidural analgesia, this technique probably carries a much lower risk of spinal haematoma in the presence of moderate haemostatic deficiencies.8 9


    Case reports
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 Abstract
 Introduction
 Case reports
 Discussion
 References
 
Case 1
A 49-yr-old Chinese woman (height 151 cm, weight 72 kg) with chronic hepatitis B and radiological evidence of cirrhosis was scheduled to undergo right lobectomy for hepatocellular carcinoma. She was otherwise in good health, with no history of gastrointestinal or cardiorespiratory problems, and no evidence of malnutrition, encephalopathy or ascites. Results of preoperative investigations included: creatinine 0.87 mg dl–1, bilirubin 1.4 mg dl–1, albumin 3.3 g dl–1, international normalized ratio (INR) 1.35 (Child's A except for a slightly low albumin level; Child-Pugh score 6; Model for End-stage Liver Disease [MELD] score 11), activated partial thromboplastin time (APTT) 34.2 s (control 26.2–38.2 s), platelet count 68x109 litre–1. Six weeks previously, she had undergone right portal vein embolization with a mixture of cyanoacrylate. Her embolization was uneventful, uncomplicated and resulted in hypertrophy of the left lobe, as planned. No transarterial chemoembolization was performed.

As the hospital intensive care unit was full, we planned a regional block with post-operative ‘rescue’ patient-controlled analgesia in order to improve her chance of early tracheal extubation after surgery. Epidural catheterization was contraindicated because of coagulopathy and thrombocytopenia, so we sited a paravertebral catheter instead. We began by inserting an 18-G Tuohy needle 2.5–3 cm lateral to the most cephalad aspect of the spinous process of T7 on the right-hand side and advanced it perpendicularly to the skin in all planes to contact the transverse process of T8 at a depth of approximately 3 cm.10 We then ‘walked’ the needle above the transverse process and gradually advanced it until a loss of resistance to air was felt.10 An epidural catheter was then passed through the lumen of the needle until its tip was 4 cm caudal to the needle tip. Radiograph confirmed accurate paravertebral placement (Fig. 1). Upon placement of appropriate monitors, general anaesthesia was induced. Through a right subcostal incision, the surgeons removed her right lobe. At the time when the surgical specimen was removed, a 20 ml bolus of plain bupivacaine 0.5% was injected over 30 min via the paravertebral catheter, followed by an infusion of bupivacaine 0.25% at 8 ml h–1, without any effect on arterial pressure. A drain was placed by the surgeon with an exit point at the L1 level in the mid-clavicular line. Overall, surgery and anaesthesia were uneventful. At the end of surgery, the patient's trachea was extubated before the patient was transferred to the recovery room, from where she was later discharged to a regular ward with continuation of the paravertebral infusion and a patient-controlled infusion of morphine.



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Fig 1 Supine anterior-posterior chest radiograph depicting a typical pattern of paravertebral spread of 14 ml of the contrast medium Omnipague® 300 mg I ml–1 (Nycomed Imaging AS, Oslo, Norway) injected with the patient sitting, via a right thoracic paravertebral catheter inserted at T7–8. The vascular tree adjacent to the contrast shadow came from an earlier right portal vein embolization with a mixture of cyanoacrylate.

 
In the post-operative period, the patient's pain scores (0=no pain, 10=worst imaginable pain) were 0–1 at rest, 1–2 on coughing and 3–4 on moving to a chair. Cumulative morphine consumption was 12 mg by 12 h, 36 mg (or 0.5 mg kg–1) by 24 h and 50.5 mg (or 0.7 mg kg–1) by 48 h. The patient's sensory block tested against cold at 24 h after surgery was between T2 and T10. Her paravertebral catheter and infusion were discontinued after 48 h. Throughout, the patient's mental status was clear and vital signs were stable. A fever (38.2°C) that was first detected on the second post-operative day lasted for two days. Her convalescence was otherwise uneventful and she was discharged from hospital nine days after surgery.

Case 2
A 52-yr-old Chinese man (height 156 cm, weight 72 kg) with moderate smoking-related lung disease, hepatitis B and hepatoma, but with no evidence of cirrhosis or malnutrition, presented for hepatectomy. His creatinine was 0.75 mg dl–1, bilirubin was 1.1 mg dl–1, albumin was 4.1 g dl–1, INR was 1.1 (Child's A, Child-Pugh score 5, MELD score 8), APTT was 32.3 s (control 26–38) s and platelet count was 125x109 litre–1. This patient did not receive prior hepatic vein embolization or transarterial chemoembolization. He received a similar right thoracic paravertebral catheter before the right lobe hepatectomy. The anaesthetic and surgical techniques were otherwise similar to Case 1, and were uncomplicated.

The local anaesthetic bolus and infusion were the same as in Case 1 (started when the surgical specimen was removed) and were without haemodynamic disturbance. He had a block from T3 to T12, as tested 10 h after surgery. Post-operatively, his pain score was 0–1 at rest, 1–2 on coughing and 2–3 on moving to a chair. Cumulative patient-controlled morphine consumption was 10.5 mg at 16 h, 12 mg (or 0.2 mg kg–1) at 24 h, 15 mg at 30 h and 18 mg (or 0.3 mg kg–1) at 48 h after surgery. His mental status and vital signs were also stable throughout the first 48 h after surgery. The infusion was stopped and the catheter was removed at 48 h after surgery. His post-operative course was complicated only by a low-grade fever (38.0–38.4°C) between the second and fourth days, and he was discharged eight days after surgery.


    Discussion
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 Abstract
 Introduction
 Case reports
 Discussion
 References
 
In post-operative pain management, most systemic agents entail some undesirable effects. Opioids depress the central nervous system. Acetaminophen is an excellent moderately potent analgesic but is a drug that, although not absolutely contraindicated in liver disease, is not normally used in hepatectomy patients in our hospital. Non-steroidal anti-inflammatory agents affect platelet function, which may already be impaired in the presence of cirrhosis, and may worsen any pre-existing cirrhosis-related renal dysfunction11 (not a problem with our two patients). Regional analgesia is highly effective and thoracic epidural block is commonly used in abdominal surgery. However, our first patient had coagulopathy and thrombocytopenia before surgery. Most patients develop coagulopathy (peaking by the first to second post-operative day24) after hepatectomy, a finding that has prompted us and clinicians at one major liver centre4 to stop performing thoracic epidurals in most such patients.

The risk of spinal haematoma should be negligible with the use of paravertebral block8 9—a technique that has been used for pain relief after liver12 and chest13 trauma, in labour,14 after thoracotomy15 and in inguinal,16 breast,17 cardiac18 and vascular19 surgery. Bleeding into the non-compressible thoracic paravertebral space is nonetheless of concern, especially when the technique is associated with vascular puncture in 3.8% of cases.20 As such, our decision to withdraw the paravertebral catheter at 48 h after surgery was contentious and involved avoiding local anaesthetic toxicity and balancing the poorly defined risks of bleeding and infection. On the one hand, any bleeding should tamponade with time, and, to date, there has not been a reported case of neurological injury or fatality directly related to bleeding after thoracic paravertebral block. On the other hand, the risk of infection increases with the duration a catheter remains in situ, and infection in the paravertebral space could be devastating.

Since a unilateral thoracic paravertebral block confers only ipsilateral pain relief and inconsistent block below T12,21 ‘rescue’ morphine is usually required during the post-operative period. To confirm our impression that the block is morphine-sparing, we obtained institutional ethics approval and retrospectively reviewed all hepatectomy cases at our hospital between October 2002 and February 2003. Of the 54 cases identified, all but one received post-operative patient-controlled analgesia. The pain scores of the 53 patients receiving patient-controlled morphine (mean weight 56 kg (SD 15 kg)) were uniformly 1–2 at rest and mean morphine consumption was 0.7 (0.3) mg kg–1 at 24 h and 1.2 (0.5) mg kg–1 at 48 h. While not convincingly so for patient 1's morphine consumption at 24 h, these data are consistent with our clinical impression that our two patients did require less morphine. Morphine consumption of our two patients was also much lower than that found in a study of Western post-hepatectomy patients without a regional block.22 Any real differences in morphine consumption and the quality of analgesia, however, can only be determined through a comparative trial involving similar patients with and without a paravertebral block.

Thoracic epidural block can be associated with marked hypotension. However, if titrated appropriately, sympathetic blockade could be exploited to decrease the central venous pressure and blood loss during hepatectomy. Our anaesthesia group has extensive experience with paravertebral blocks, and has found that significant hypotension rarely occurs.9 13 22 In the absence of this potential advantage, we did not see a great difference between establishing the paravertebral block early or late during surgery. Another difference between an epidural block and a paravertebral block is that the latter does not usually cause urinary retention.9

Systemic accumulation of local anaesthetic may occur after prolonged paravertebral infusion. Although total plasma concentrations of local anaesthetic increase with time, the concentration of free (unbound) local anaesthetic remains unchanged in the post-operative period.23 This may explain why toxicity is rare after post-operative paravertebral infusion. Nevertheless, because of decreased hepatic clearance in patients with compromised liver function, until more data on local anaesthetic pharmacokinetics after thoracic paravertebral infusion is available, continuing an infusion much beyond 48 h after hepatectomy may not be advisable.

Our experience suggests that right thoracic paravertebral block is a possible analgesia option for patients undergoing hepatectomy in whom epidural block is contraindicated. Comparative studies on the use of thoracic paravertebral block in patients undergoing extensive liver resection may be worthwhile.


    References
 Top
 Abstract
 Introduction
 Case reports
 Discussion
 References
 
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2 Suc B, Panis Y, Belghiti J, et al. ‘Natural history’ of hepatectomy. Br J Surg 1992; 79: 39–42[ISI][Medline]

3 Borromeo CJ, Stix MS, Lally A, et al. Epidural catheter and increased prothrombin time after right lobe hepatectomy for living donor transplantation. Anesth Analg 2000; 91: 1139–41[Abstract/Free Full Text]

4 Yong BH, Ng KF, Tsui SL, et al. Coagulopathy after donor hepatectomy— implications for postoperative analgesia. Anaesth Intensive Care 2001; 29: 654–5

5 Lin MC, Wu CC, Ho WL, et al. Concomitant splenectomy for hypersplenic thrombocytopenia in hepatic resection for hepatocellular carcinoma. Hepatogastroenterology 1999; 46: 630–4[Medline]

6 Koruk M, Onuk MD, Akcay F, Savas MC. Serum thrombopoietin levels in patients with chronic hepatitis and liver cirrhosis, and its relationship with circulating thrombocyte counts. Hepatogastroenterology 2002; 49: 1645–8[ISI][Medline]

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12 Hall H, Leach A. Paravertebral block in the management of liver capsule pain after blunt trauma. Br J Anaesth 1999; 83: 819–21[Abstract/Free Full Text]

13 Karmakar MK, Critchley LA, Ho AMH, et al. Continuous thoracic paravertebral infusion of bupivacaine for pain management in patients with multiple fractured ribs. Chest 2003; 123: 424–31[Abstract/Free Full Text]

14 Nair V, Henry R. Bilateral paravertebral block: a satisfactory alternative for labour analgesia. Can J Anesth 2001; 48: 179–84[Abstract/Free Full Text]

15 Karmakar MK, Booker PD, Franks R. Bilateral continuous paravertebral block used for postoperative analgesia in an infant having bilateral thoracotomy. Paediatr Anaesth 1997; 7: 469–71[ISI][Medline]

16 Wassef MR, Randazzo T, Ward W. The paravertebral nerve root block for inguinal herniorrhaphy–a comparison with the field block approach. Reg Anesth Pain Med 1998; 23: 451–6[CrossRef][ISI][Medline]

17 Klein SM, Bergh A, Steele SM, et al. Thoracic paravertebral block for breast surgery. Anesth Analg 2000; 90: 1402–5[Abstract/Free Full Text]

18 Cantó M, Sánchez MJ, Casas MA, et al. Bilateral paravertebral blockade for conventional cardiac surgery. Anaesthesia 2003; 58: 365–70[ISI][Medline]

19 Richardson J, Vowden P, Sabanathan S. Bilateral paravertebral analgesia for major abdominal vascular surgery: a preliminary report. Anaesthesia 1995; 50: 995–8[ISI][Medline]

20 Lönnqvist PA, MacKenzie J, Soni AK, et al. Paravertebral blockade. Failure rate and complications. Anaesthesia 1995; 50: 813–15[ISI][Medline]

21 Karmakar MK, Gin T, Ho AMH. Ipsilateral thoraco-lumbar anaesthesia and paravertebral spread after low thoracic paravertebral injection. Br J Anaesth 2001; 87: 312–16[Abstract/Free Full Text]

22 Moretti EW, Robertson KM, Tuttle-Newhall JE, et al. Orthotopic liver transplant patients require less postoperative morphine than do patients undergoing hepatic resection. J Clin Anesth 2002; 14: 416–20[CrossRef][ISI][Medline]

23 Dauphin A, Gupta RN, Young JE, et al. Serum bupivacaine concentrations during continuous extrapleural infusion. Can J Anesth 1997; 44: 367–70[Abstract]





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