1 Stirling Royal Infirmary, Stirling and 2 Anaesthetic Department, Western Infirmary and Gartnavel General Hospital, Glasgow, UK
* Corresponding author: Stirling Royal Infirmary, Livilands, Stirling FK8 2AU, UK. E-mail: Andrew.Woods{at}fvah.scot.nhs.uk
Keywords: anaesthetic techniques ; intubation, endotracheal
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Introduction |
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Before this, tracheal intubation was usually performed under deep inhalational anaesthesia with ether. The continuing use of this technique to facilitate tracheal intubation with halothane and subsequently sevoflurane is still established, especially in paediatric practice. Since the advent of shorter-acting opioid drugs, intubating the trachea has been particularly successful when these drugs are used in combination with propofol. The technique has gained a small but popular niche in the armoury of the anaesthetist, when use of a neuromuscular blocking drug is undesirable. It may be used when there is a contraindication to a neuromuscular blocking drug, or in cases where tracheal intubation is necessary but prolonged muscle relaxation is not, such as in short ENT or gynaecological procedures. The technique may be the one of choice for the anaesthetist, using it as part of total intravenous anaesthesia without the use of a neuromuscular blocking drug. One avoids the potential serious and unwanted side-effects of succinylcholine, as well as the less common ones of non-depolarizing drugs, such as anaphylaxis. This review concentrates on the many studies that detail different techniques to intubate the trachea without muscle relaxation. Although no two studies are the same, and criteria for optimal intubating conditions vary, this review provides insight into how to approach this technique. The literature on this subject was retrieved using Medline (Pubmed, Medline Plus). The following search terms were used alone and in combination: tracheal intubation, inhalational anaesthetics, lidocaine, fentanyl, alfentanil, remifentanil, haemodynamic response, pressor response, complications.
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Inhalational agents |
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The same group then applied these study techniques to enflurane in a similar age group of patients and found the corrected MACEI value to be 2.9%.95 For both halothane and enflurane, the MACEI appears to be about 30% greater than the MAC value. However, enflurane is known to produce central nervous system excitation at an alveolar concentration of 2.5%, and in 15 out of 17 patients studied, tonicclonic twitching of the hands and feet was observed, making it an unsuitable agent for this purpose.52 Other complications of this technique with enflurane included a decrease in chest wall compliance and difficulty with ventilation. No similar studies have been published using isoflurane or desflurane, which is hardly surprising considering their potential for airway irritation.86
Sevoflurane
Children
Although halothane has been used for many years for smooth inhalational induction and good intubating conditions, it has been largely superseded by sevoflurane in the UK since the mid to late 1990s. The vast majority of publications in this subject have involved the inhalation of sevoflurane, using various approaches and combinations of other agents.
A group of Japanese workers produced a series of studies, mostly in children, designed similar to those of Yakaitis, before sevoflurane became available in the UK. In the first of these, 36 children aged 19 yr were studied.40 If the patient coughed or made purposeful movement, they were given a bolus of thiopental or succinylcholine and excluded from the study, leaving 22 suitable patients. Each concentration at which laryngoscopy and tracheal intubation were attempted was predetermined with an up-and-down method, using 0.5% as a step size and a single measurement was obtained per patient. Laryngoscopy and intubation were attempted only after the ratio of alveolar to predetermined inspiratory concentration had been maintained at greater than 0.95 for 15 min. The calculated MACEI for sevoflurane was 2.7%, 30% above the MAC50 level of 2% for this age group, agreeing with the results from the halothane and enflurane studies by Yakaitis.94 95 The same group of investigators then compared the MACEI with the MAC to prevent movement in 50% of patients undergoing laryngeal mask insertion. Forty-two children aged 19 yr were studied,85 and the MACEI was similar to before, at 2.8%. Using this information, a study was designed to see how quickly, and at what optimal end-tidal concentration, the trachea could be intubated.39 Twenty-nine children were studied, aged 28 yr. The breathing circuit was saturated with sevoflurane 5% and the children were allocated to seven predetermined end-tidal concentrations before induction, ranging from 1.5 to 4.5%, in 0.5% increments. The results showed that 80 and 100% of patients underwent smooth tracheal intubation at end-tidal concentrations of 4 and 4.5% respectively, and that the effective dose for 50% of the population (ED50, equivalent to the MACEI) was 3.1%. This is 0.30.4% higher than previously reported in a similar group of patients, presumably because of the difference in brain concentrations as a result of a shorter intubation time. The time taken to reach an end-tidal concentration of 4.5% and intubate averaged 210 s. However, numbers were small, ranging between two and eight patients in each group. The addition of nitrous oxide 33 and 66% has been shown to decrease the MACEI value in children aged 17 yr by 18 and 40%, from 2.7% with sevoflurane alone, to 2.2% and 1.6% respectively.84 This is entirely predictable, considering the additive effect on MAC of nitrous oxide.
Different inhalational agents have also been compared. In one study, O'Brien and colleagues67 studied 40 fit, healthy children, aged 310 yr in a double-blind randomized controlled trial. Patients were induced with either halothane and nitrous oxide 60%, or sevoflurane and nitrous oxide 60%. The concentrations of each potent inhalational agent were increased gradually to 5 and 8% respectively and the trachea was intubated when the pupils were small and central. The mean time to reach the clinical end-point for intubation was 200 s for the halothane group and 243 s for the sevoflurane group (P=0.015). Satisfactory intubating conditions, based on the Helbo-Hansen scoring system,35 were achieved in 19/20 patients in each group. In the sevoflurane group, however, only seven out of 20 patients had an ideal score, compared with 12 out of 20 patients in the halothane group. The time to tracheal intubation (TimeEI) using equipotent concentrations of sevoflurane (5%) and halothane (2.5%) has also been compared in 40 children aged 17 yr.41 Using the up and down method starting at 240 s, the TimeEI 50 and TimeEI 95 for the sevoflurane/halothane groups were 147 s/214 s and 194 s/255 s respectively, consistent with their relevant blood gas solubility.
The success of these previous studies led researchers to determine if sevoflurane alone could achieve as rapid and effective intubating conditions as thiopental and succinylcholine. This would make it a potentially attractive technique to intubate the trachea for short procedures. Thwaites and colleagues studied 64 healthy children aged 310 yr,88 undergoing tonsillectomy, receiving either sevoflurane 8% and nitrous oxide 66% in oxygen, or propofol 34 mg kg1 and succinylcholine 2 mg kg1. Both groups were intubated at 150 s by a blinded investigator. Although intubation was successful in all cases, excellent conditions were scored in only 55% of cases in the sevoflurane group, compared with 82% cases in the propofol/succinylcholine group.
Using a technique from a previous study, sevoflurane 8% in nitrous oxide 60% was compared with propofol/succinylcholine (3 mg kg1 and 1 mg kg1) and propofol/alfentanil (3 mg kg1 and 10 µg kg1) in 120 children aged 312 yr.6 Patients in the sevoflurane group were intubated after 3 min, whilst the other groups were intubated after 60 s. Acceptable conditions were found in 97.5, 87.5 and 52.5% respectively, prompting the authors to state that the sevoflurane technique is a satisfactory alternative to the gold standard of succinylcholine and propofol when intubating children in a non-urgent situation. The mean end-tidal concentration just before intubation was 4.2%. This agrees with the previously quoted studies that an end-tidal concentration of 2xMAC is required for successful intubation in almost all children. This would take approximately 3 min under normal circumstances when breathing these high concentrations of sevoflurane.
Adults
Similar methods were used to determine the MACEI in adults, who seem to require much higher concentrations of volatile agent than children for the same effect.47 In 86 ASA I or II adult patients, the MACEI sevoflurane for 50% of the population was 4.5%. The authors account for this difference by the irritation and subsequent coughing caused by the cuff of adult tracheal tubes, and the fact that children have a relatively greater brain perfusion and quicker uptake. In another study, 20 healthy adult volunteers were anaesthetized on three separate occasions, using three different techniques:66 technique 1 was tracheal intubation after induction with sevoflurane 67% and nitrous oxide 66%; technique 2 was tracheal intubation after induction with sevoflurane 67% and oxygen 100%; and technique 3 was laryngeal mask insertion after induction with sevoflurane 67% and nitrous oxide 66%. The time to successful intubation was used as the end-point. The mean time in the sevoflurane/oxygen 100% group was 6.4 min, longer than that of the sevoflurane/nitrous oxide 66% group at 4.7 min. It can therefore be seen that even when breathing sevoflurane 8%, a significantly longer period of inhalation is required for adults.
Sevoflurane 8% can be as satisfactory as neuromuscular blocking drugs for producing the necessary conditions for intubating the trachea, but cannot achieve the speed of onset of effect for rapid sequence intubation. Iamaroon studied 120 adult patients,38 randomized into receiving thiopental 5 mg kg1 and succinylcholine 1 mg kg1, or sevoflurane 8% in nitrous oxide 66%. The succinylcholine group were intubated by a blinded investigator at 1 min and achieved almost 100% success rate with good or excellent conditions, whereas the sevoflurane group breathed 3 vital capacity breaths in a primed circuit followed by 4 min normal breathing to achieve almost the same results.
To achieve a similar time profile to children, adults need to be premedicated. In one study, 24 healthy adult volunteers were anaesthetized on three separate occasions,65 and premedicated with fentanyl (2.4 µg kg1), midazolam (36 µg kg1) or both drugs (B) using a quarter of the doses because of a previously described synergistic effect.4 Patients breathed sevoflurane 8% and nitrous oxide 66% in oxygen at time intervals varying between 2.5 and 6.5 min. Logistic regression analyses showed that good-quality intubating conditions could be achieved after 3.1 min and 2.5 min in the midazolam and combined groups respectively, several minutes shorter than in the fentanyl group. This is surprising, as it has been reported previously that midazolam and fentanyl have similar MAC sparing properties, but it may be that the synergistic effect mentioned previously was not evident here.4 The authors speculate that this inconsistency arises from the increased chest wall rigidity seen in the patients receiving fentanyl, leading to a reduced minute volume, and hence less delivery of anaesthetic to the alveoli. Katoh and colleagues44 pretreated a group of 80 ASA III adults with fentanyl 1, 2 and 4 µg kg1, given 4 min before intubation. This resulted in a markedly decreased MACEI of sevoflurane of 2.07, 1.45 and 1.37% respectively, compared with 3.55% without fentanyl. Similarly, the addition of remifentanil 1 µg kg1 followed by an infusion of 0.25 µg kg1 min1 reduced the MACEI to 2%, the MACEI of 95% of the population being 3.2%.15
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Difficult airway |
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Lidocaine |
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Several papers have also examined the effectiveness of intravenous lidocaine to suppress the cough reflex.69 79 Yukioka and colleagues96 showed that the optimum dose to suppress the cough reflex completely was 2 mg kg1 administered intravenously at 1 min before intubation. However, even though the authors did not report any patient with significant side-effects, they conclude that this dose may be associated with systemic toxicity, some patients having blood concentrations as high as 8 µg kg1, as measured by gas chromatography from regular arterial sampling.
Tracheal intubation causes a marked pressor response, raising the mean arterial pressure and mean heart rate significantly.77 This may be potentially harmful in patients with cardiac disease or raised intracranial pressure, and may be exaggerated in both treated and untreated hypertensive patients.70 Lidocaine does not appear to alter this response. Miller and colleagues63 found no protective effect when 1.5 mg kg1 was administered 3 min before laryngoscopy. Similar findings were seen in a study by Chraemmer-Jorgensen,11 using the same dose given 2 min before laryngoscopy. The addition of laryngotracheal lidocaine seems to be more successful in facilitating tracheal intubation. Bulow and colleagues10 used propofol 2.5 mg kg1 and alfentanil 30 µg kg1, and then sprayed the vocal cords with lidocaine 160 mg 90 s before intubation. Satisfactory conditions were obtained in all 27 patients in this group compared with 73% in the saline group. But laryngotracheal administered lidocaine does not alter this pressor response to laryngoscopy and tracheal intubation.32 51
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Induction agents |
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Propofol provides better jaw relaxation and attenuation of laryngeal reflexes than thiopental.61 When used alone for tracheal intubation, propofol 2.5 mg kg1 provided satisfactory conditions in 19/20 (96%) patients and ideal intubating conditions in 14/20 (60%) patients.45 These patients were premedicated with diazepam 10 mg and droperidol 5 mg, and therefore the results may be better than expected. This contrasts with Mulholland and Carlisle,64 who found that 56% of patients had unsatisfactory conditions with the same dose of propofol. However, the method and standard end-points for quality of tracheal intubation vary in these two studies.
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Opioids |
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Fentanyl
Fentanyl has been shown to blunt the pressor response to laryngoscopy and intubation optimally 5 min after administration, which is longer than after alfentanil or remifentanil.50 Streibel and colleagues83 designed a double-blind, randomized controlled trial to compare the intubating conditions between thiopental (mean 5.5 mg kg1)/fentanyl 100 µg/succinylcholine 1 mg kg1 and propofol (mean 2.4 mg kg1)/fentanyl 100 µg. No significant differences were found in overall intubating conditions between the two groups of 25 gynaecological patients.
In a study of 60 ASA I or II children, De Fatima and colleagues19 found that fentanyl 3 µg kg1 given 5 min before propofol 3 mg kg1 was the optimal dose regime, and resulted in satisfactory intubating conditions in 75% of patients. This is compared with 20% (P<0.05) and 80% (n.s.) of patients given propofol 2.5 mg kg1 and 3.5 mg kg1 respectively.
Alfentanil
Alfentanil has been used successfully as an adjunct to blunt the pressor response5 14 57 and to allow faster tracheal intubation when combined with non-depolarizing neuromuscular blocking drugs.16 29 Table 1 summarizes the many studies using alfentanil as an alternative to neuromuscular blocking drugs for intubation of the trachea. Most studies vary in design, type of premedication, dose of alfentanil and clinical end-point, making it difficult to decide on the best drug regimen. Doses given vary between alfentanil 10 and 50 µg kg1. With doses as low as 10 µg kg1, Alcock and colleagues1 found that good or excellent conditions were found in 43/50 (86%) of patients, five out of the 50 patients requiring succinylcholine to facilitate intubation. This is in contrast to Davidson and Gillepsie,17 who found that, with the same dose, intubating conditions were ideal in only 20% patients, increasing to 73% when the dose was doubled to 20 µg kg1, after induction with propofol 2.5 mg kg1 (Table 1). It is difficult to understand why there is such a discrepancy in the results of these two studies, as both used similar methods and had similar criteria for intubating conditions. This may highlight the wide subjectivity when assessing individual variables such as coughing and vocal cord movement. This success rate was increased in a study by Grange and colleagues,25 14/15 (93%) patients having ideal or satisfactory intubating conditions after receiving alfentanil 20 µg kg1. The main difference with this study was using a time, predetermined from a pilot study, after injecting propofol 2.5 mg kg1 to intubating of 45 s. The previous two studies used loss of eyelash reflex as an end-point, and had no reference to the timing of intubation, perhaps resulting in less optimal plasma concentrations of alfentanil.
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Alfentanil has been used successfully in a case of a difficult airway after both fibre-optic intubation and deep inhalational anaesthesia with halothane had failed.59 The authors used alfentanil 25 µg kg1 followed by propofol 1 mg kg1 to visualize the glottis, and stated that the effects of alfentanil could have been readily antagonized by naloxone if necessary. Others have reservations about the use of alfentanil in a potentially difficult airway, and are guarded about the ease of reversibility with naloxone and the relatively high failure rate of intubation with this dose.24 53 These authors advise caution and state that the technique of choice in such situations is always awake fibre-optic intubation.
Remifentanil
Remifentanil has a similar clinical onset time to alfentanil and has also been found to blunt the pressor response to tracheal intubation.31 68 87 Studied in comparable doses, the degree of attenuation is similar.60 Table 2 summarizes the studies involving remifentanil to facilitate tracheal intubation. Again, most studies vary in the timing of drug administration, study design and doses, varying between remifentanil 0.5 and 5 µg kg1. In the first of these studies, Stevens and Wheatly80 found that remifentanil 3 µg kg1, given with propofol 2 mg kg1, was the minimum dose necessary to produce acceptable intubating conditions in nearly all patients. A dose of 2 µg kg1 was associated with an incidence of 75% in good or ideal conditions, whereas clinically acceptable intubating conditions were recorded in only 35% of patients given 1 µg kg1. The results of this study are similar to studies conducted by Grant and Woods,26 92 93 which show that remifentanil 2 µg kg1 consistently provides good or ideal intubating conditions in 8090% of patients. This contrasts with the work of others,3 48 62 who have found that doses as high as 4 µg kg1 are necessary to obtain excellent conditions in most patients (Table 2). In most of these studies, at doses of remifentanil 2 µg kg1 and above, blood pressure and heart rate are significantly reduced compared with baseline levels, leaving most authors to conclude that the technique is not to be recommended in elderly or compromised patients.
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A rapid sequence induction using remifentanil has been described in a 12-yr-old child with a potentially difficult airway, after a gunshot wound. The patient had a family history of malignant hyperpyrexia, and a propofolremifentanil induction was deemed the technique of choice in this unusual situation, in which neither an awake fibre-optic intubation nor tracheostomy would have been appropriate. The patient received propofol 3 mg kg1 and remifentanil 4 µg kg1 and underwent uneventful laryngoscopy and subsequent anaesthesia.34
In most of the studies assessing intubating conditions with the short-acting opioid drugs, induction with propofol has been carried out. Neither thiopental nor etomidate can provide similar conditions for this situation.21
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Conclusions |
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References |
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2 Alexander R, Booth J, Olufalabi A, El-Moalem E, Glass PS. Comparison of remifentanil with alfentanil or suxamethonium following propofol anaesthesia for tracheal intubation. Anaesthesia 1999; 54: 10326[CrossRef][ISI][Medline]
3 Alexander R, Olufalabi A, Booth J, El-Moalem E, Glass PS. Dosing study of remifentanil for tracheal intubation without the use of muscle relaxants. Anaesthesia 1999; 54: 103740[CrossRef][ISI][Medline]
4 Ben Shlomo I, abd-el-Kalim H, Ezry J. Midazolam acts synergistically with fentanyl for induction of anaesthesia. Br J Anaesth 1990; 64: 457[Abstract]
5 Black TE, Kay B, Healy TE. Reducing the haemodynamic responses to laryngoscopy and intubation with alfentanil and fentanyl. Anaesthesia 1984; 39: 8837[ISI][Medline]
6 Blair JM, Hill DA, Bali IM, Fee JPH. Tracheal intubating conditions after induction with sevoflurane 8% in children. Anaesthesia 2000; 55: 7748[CrossRef][ISI][Medline]
7 Blair JM, Hill DA, Wilson CM, Fee JP. Assessment of tracheal intubation in children after induction with propofol and different doses of remifentanil. Anaesthesia 2004; 59: 2733[CrossRef][ISI][Medline]
8 Board P. Sevoflurane for difficult tracheal intubation. Br J Anaesth 1998; 81: 14
9 Bourne JG. Thiopentonenitrous oxideoxygen anaesthesia with curare for head and neck surgery. Br Med J 1947; 2: 6545
10 Bulow K, Nielsen TG, Lund J. The effect of topical lignocaine on intubating conditions after propofol-alfentanil induction. Acta Anaesthesiol Scand 1996; 40: 7526[ISI][Medline]
11 Chraemmer-Jorgenson B, Hoilund-Carlsen PF, Marving J, Christensen V. Lack of effect of intravenous lidocaine on haemodynamic responses to rapid sequence induction of general anesthesia. Anesth Analg 1986; 65: 103741[Abstract]
12 Coghlan SFE, McDonald PF, Csepregi G. Use of alfentanil with propofol for nasotracheal intubation without neuromuscular block. Br J Anaesth 1993; 70: 8991[Abstract]
13 Collins S, Prentice E, Vaghadia H. Tracheal intubation of outpatients with and without muscle relaxants. Can J Anesth 2000; 47: 42732
14 Crawford DC, Fell D, Achola KJ, Smith G. Effects of alfentanil on the pressor and catecholamine responses to tracheal intubation. Br J Anaesth 1987; 59: 70712[Abstract]
15 Cros AM, Lopez C, Kandel T, Sztark F. Determination of sevoflurane alveolar concentration for tracheal intubation with remifentanil, and no muscle relaxant. Anaesthesia 2000; 55: 9659[CrossRef][ISI][Medline]
16 Crul JF, Vanbelleghem V, Buyse L, Heylen R, Van Egmond J. Rocuronium with alfentanil and propofol allows intubation within 45 s. Eur J Anaesth 1995; 12: 1112[ISI]
17 Davidson JAH, Gillespie JA. Tracheal intubation after induction of anaesthesia with propofol, alfentanil and i.v. lignocaine. Br J Anaesth 1993; 70: 1636[Abstract]
18 Davies MW. Sevoflurane; a note of caution. Anaesthesia 1996; 51: 1082
19 De Fatima de Assuncao Braga A, Da Silva Braga FS, Poterio GM, Filier PR, Cremonesi E. The effect of different doses of propofol on tracheal intubating conditions without muscle relaxant in children. Eur J Anaesth 2001; 18: 3848[CrossRef][ISI][Medline]
20 Elsberg CA. Clinical experiences with intratracheal insufflation with remarks upon the value of the method for thoracic surgery. Ann Surg 1910; 52: 239
21 Erhan E, Uger G, Gunusen I, Alper I, Ozyar B. Propofolnot thiopental or etomidatewith remifentanil provides adequate intubating conditions in the absence of neuromuscular blockade. Can J Anesth 2004; 50: 10815[ISI]
22 Fenlon S, Pearce A. Sevoflurane induction and difficult airway management. Anaesthesia 1997; 52: 2856
23 Ghouri AF, White PF. Effect of fentanyl and nitrous oxide on the desflurane anesthetic requirement. Anesth Analg 1991; 72: 37781[Abstract]
24 Gillespie JA, Pace N, Henderson JJ. Alfentanil and propofol for difficult tracheal intubation. Br J Anaesth 1994; 72: 498
25 Grange CS, Suresh D, Meikle R, Carter JA, Goldhill DR. Intubation with propofol: evaluation of pre-treatment with alfentanil or lignocaine. Eur J Anaesth 1993; 10: 912[Medline]
26 Grant S, Noble S, Woods A, Murdoch J, Davidson JAH. Assessment of intubating conditions in adults after induction with propofol and varying doses of remifentanil. Br J Anaesth 1998; 81: 54054
27 Gray TC, Halton J. A milestone in anaesthesia (d-tubocurarine chloride). Proc R Soc Med 1946; 39: 4008[ISI]
28 Griffith HR, Johnson GE. The use of curare in general anesthesia. Anesthesiology 1942; 3: 41820
29 Groener R, Moyes DG. Rapid tracheal intubation with propofol, alfentanil and a standard dose of vecuronium. Br J Anaesth 1997; 79: 3845
30 Gupta S, Wilson JU. Sevoflurane for inhalational induction in patients with anticipated difficult intubation. Acta Anaesthesiol Scand 1998; 42: 1232
31 Hall AP, Thompson JP, Leslie NA, Fox AJ, Kumar N, Rowbotham DJ. Comparison of different doses of remifentanil on the cardiovascular response to laryngoscopy and tracheal intubation. Br J Anaesth 2000; 84: 1002[Abstract]
32 Hamill JF, Bedford RF, Weaver DC, Colohan AR. Lidocaine before endotracheal intubation: Intravenous or laryngotracheal. Anesthesiology 1981; 55: 57881[ISI][Medline]
33 Harsten A, Gillberg L. Intubating conditions provided by propofol and alfentanil-acceptable, but not ideal. Acta Anaesthesiol Scand 1997; 41: 9857[ISI][Medline]
34 Haughton A, Turley A, Pollock N. Remifentanil for rapid sequence induction. Anaesth Intensive Care 1999; 27: 31920
35 Helbo-Hansen S, Ravlo O, Trap-Anderson S. The influence of alfentanil on the intubating conditions after priming with vecuronium. Acta Anaesthesiol Scand 1988; 32: 414[ISI][Medline]
36 Hiller A, Klemola UM, Saarnivaara L. Tracheal intubation after induction of anaesthesia with propofol, alfentanil and lidocaine without neuromuscular blocking drugs in children. Acta Anaesthesiol Scand 1993; 37: 7259[ISI][Medline]
37 Hovorka J, Honkavaara P, Kortilla K. Tracheal intubation after induction of anaesthesia with thiopentone or propofol without muscle relaxants. Acta Anaesthesiol Scand 1991; 35: 3268[ISI][Medline]
38 Iamaroon A, Pitimana-aree S, Prechawi C, Anusit J, Somcharoen K, Caiyarroj O. Endotracheal intubation with thiopental/succinylcholine or sevoflurane/nitrous oxide in adults: a comparative study. Anesth Analg 2001; 92: 5238
39 Inomata S, Nishikawa T. Determination of end tidal sevoflurane concentration for tracheal intubation with the rapid method. Can J Anesth 1996; 43: 80611[Abstract]
40 Inomata S, Watanabe S, Taguchi M, Okada M. End tidal sevoflurane concentration for tracheal intubation and minimum alveolar concentration in pediatric patients. Anesthesiology 1994; 80: 936[ISI][Medline]
41 Inomata S, Yamashita S, Toyooka H, Yaguchi Y, Taguchi M, Sato S. Anaesthetic induction time for tracheal intubation using sevoflurane or halothane in children. Anaesthesia 1998; 53: 4405[CrossRef][ISI][Medline]
42 Ip-Yam P.C. Sevoflurane for difficult tracheal intubation. Br J Anaesth 1998; 81: 104
43 Kandasamy R, Sivalingam P. Use of sevoflurane in difficult airways. Acta Anaesthiol Scand 2000; 44: 6279[CrossRef][ISI][Medline]
44 Katoh T, Nakajima Y, Moriwaki G, et al. Sevoflurane requirements for tracheal intubation with and without fentanyl. Br J Anaesth 1999; 82: 5615
45 Keaveny JP, Knell PJ. Intubation under induction doses of propofol. Anaesthesia 1988; 43: 801[Medline]
46 Kelly RE. Anaesthesia by the intratracheal insufflation of ether. Br Med J 1912; 3: 112
47 Kimuru T, Watanabe S, Asakura N, Inomata S, Okada M, Taguchi M. Determination of end tidal sevoflurane concentration for tracheal intubation and minimum alveolar concentration in adults. Anesth Analg 1994; 79: 37881[Abstract]
48 Klemola UM, Hiller A. Tracheal intubation after induction of anesthesia in children with propofolremifentanil or propofolrocuronium. Can J Anesth 2000; 47: 8549
49 Klemola UM, Mennander S, Saarnivaara L. Tracheal intubation without the use of muscle relaxants: remifentanil or alfentanil in combination with propofol. Acta Anaesthesiol Scand 2000; 44: 4659[CrossRef][ISI][Medline]
50 Ko SH, Kim DC, Han YJ, Song HS. Small-dose fentanyl: optimal time of injection for blunting the circulatory responses to tracheal intubation. Anesth Analg 1998; 86: 65861[Abstract]
51 Laurito CE, Bangham VL, Becker GL, Polek WV, Reigler FX, Vadenboncouer TR. Effects of aerosolised and/or intravenous lidocaine on haemodynamic responses to laryngoscopy and intubation in out-patients. Anesth Analg 1988; 67: 38992[Abstract]
52 Lebowitz MH, Blitt CD, Dillon JG. Enflurane-induced central nervous system excitation and its relation to carbon dioxide tension. Anesth Analg 1972; 51: 35563[Medline]
53 Levitt MJ, Woods LA. Alfentanil and propofol for difficult tracheal intubation. Br J Anaesth 1994; 72: 4978
54 Lewis CB. Endotracheal intubation under thiopentone. Anaesthesia 1948; 3: 113
55 MacEwen W. Clinical observations on the introduction of tracheal tubes by the mouth instead of performing tracheotomy or laryngotomy. Br Med J 1880; 2: 122
56 MacIntyre PA, Ansari KA. Sevoflurane for predicted difficult tracheal intubation. Eur J Anaesth 1998; 15: 4626[CrossRef][ISI][Medline]
57 Martineau RJ, Tousignant CP, Miller DR, Hull KA. Alfentanil controls the haemodynamic response during rapid sequence induction of anaesthesia. Can J Anesth 1989; 37: 75581[ISI]
58 McConaghy P, Bunting HE. Assessment of intubating conditions in children after induction with propofol and varying doses of alfentanil. Br J Anaesth 1994; 73: 5969[Abstract]
59 McDonald PF. Use of alfentanil and propofol for difficult tracheal intubation. Br J Anaesth 1993; 71: 773
60 McGuire AM, Kumar N, Parker JL, Rowbotham DJ, Thompson JP. Comparison of remifentanil and alfentanil on cardiovascular response to tracheal intubation in hypertensive patients. Br J Anaesth 2001; 86: 903
61 McKeating K, Bali IM, Dundee JW. The effects of thiopentone and propofol on upper airway integrity. Anaesthesia 1988; 43: 63840[ISI][Medline]
62 McNeil IA, Culbert B, Russell I. Comparison of intubating conditions following propofol and succinylcholine with propofol and remifentanil 2 µg kg1 or 4 µg kg1. Br J Anaesth 2000; 85: 6235
63 Miller CD, Warren SJ. I.V. lignocaine fails to attenuate the cardiovascular response to laryngoscopy and tracheal intubation. Br J Anaesth 1990; 65: 2169[Abstract]
64 Mulholland D, Carlisle RJT. Intubation with propofol augmented with intravenous lignocaine. Anaesthesia 1991; 46: 3123[ISI][Medline]
65 Muzi M, Colinco MD, Robinson BJ, Ebert TJ. The effects of premedication on inhaled induction of anesthesia with sevoflurane. Anesth Analg 1997; 85: 11438[Abstract]
66 Muzi M, Robinson BJ, Ebert TJ, O'Brien TJ. Induction of anesthesia and tracheal intubation with sevoflurane in adults. Anesthesiology 1996; 85: 53643[CrossRef][ISI][Medline]
67 O'Brien K, Kumar R, Morton NS. Sevoflurane compared with halothane for tracheal intubation in children. Br J Anaesth 1998; 80: 4525[CrossRef][ISI][Medline]
68 O'Hare R, McAtamney D, Mirakhur RK, Hughes D, Carabine U. Bolus dose remifentanil for control of haemodynamic response to tracheal intubation during rapid sequence induction of anaesthesia. Br J Anaesth 1999; 82: 2835
69 Poulton TJ, James FM. Cough suppression by lidocaine. Anesthesiology 1979; 50: 4702[ISI][Medline]
70 Prys-Roberts C, Greene LT, Melloche R, Foëx P. Studies of anaesthesia in relation to hypertension. II: Haemodynamic consequences of induction and endotracheal intubation. Br J Anaesth 1971; 43: 53147[ISI][Medline]
71 Robinson DN, O'Brien K, Kumar R, Morton NS. Tracheal intubation without neuromuscular blockade in children: a comparison of propofol combined with either alfentanil or remifentanil. Paediatr Anaesth 1998; 8: 46771[CrossRef][ISI][Medline]
72 Rowbotham S. Intratracheal anaesthesia. Lancet 1920; 2: 5834[CrossRef][ISI]
73 Rowbotham S. Intratracheal anaesthesia by the nasal route for operations on the mouth and lips. Br Med J 1920; 3: 5901
74 Rushman GB, Davies NJH, Atkinson RS. A Short History of Anaesthesia: Intubation of the Trachea. Oxford: Butterworth-Heinneman, 1996; 927
75 Saarnivaara L, Klemola UM. Injection pain, intubating conditions and cardiovascular changes following induction of anaesthesia with propofol alone or in combination with alfentanil. Acta Anaesthesiol Scand 1991; 35: 1923[ISI][Medline]
76 Scheller MS, Zornow MH, Saidman LJ. Tracheal intubation without the use of muscle relaxants: a technique using propofol and varying doses of alfentanil. Anesth Analg 1992; 75: 78893[Abstract]
77 Shribman AJ, Smith G, Achola KJ. Cardiovascular and catecholamine response to laryngoscopy with and without endotracheal intubation. Br J Anaesth 1987; 59: 2959[Abstract]
78 Spalding M, Ala-Koko TI. The use of inhaled sevoflurane for endotracheal intubation in epiglottitis. Anesthesiology 1998; 89: 10266[CrossRef]
79 Stenhause JE, Gaskin L. A study of intravenous lidocaine as a suppressant of cough reflex. Anesthesiology 1963; 24: 28590[ISI]
80 Stevens JB, Wheatly L. Tracheal intubation in ambulatory surgery patients: using remifentanil and propofol without muscle relaxants. Anesth Analg 1998; 86: 459[Abstract]
81 Stevens JB, Vescovo V, Harris KC, Walker SC, Hickey R. Tracheal intubation using alfentanil and no muscle relaxant: is the choice of hypnotic important? Anesth Analg 1997; 84: 12226[Abstract]
82 Steyn M, Quinn A, Gillespie JA, Miller D, Best C, Morton N. Tracheal intubation without neuromuscular block in children. Br J Anaesth 1994; 72: 4036[Abstract]
83 Streibel HW, Holzl M, Reiger A, Brummer G. Endotracheal intubation with propofol and fentanyl. Anaesthetist 1995; 44: 80917[CrossRef][ISI][Medline]
84 Swan DH, Crawford MW, Pua HL, Stephens D, Lerman J. Additive contribution of nitrous oxide to sevoflurane minimum alveolar concentration for tracheal intubation in children. Anesthesiology 1999; 91: 66771[CrossRef][ISI][Medline]
85 Taguchi M, Watanabe S, Asakura N, Inomata S. End tidal sevoflurane concentration for laryngeal mask airway insertion and for tracheal intubation in children. Anesthesiology 1994; 81: 62831[ISI][Medline]
86 TerRiet MF, De Souza GJ, Jacobs JS, et al. Which is the most pungent: isoflurane, sevoflurane or desflurane. Br J Anaesth 2000; 85: 3057
87 Thompson JP, Hall AP, Russell J, Cagney B, Rowbotham DJ. Effect of remifentanil on the haemodynamic response to orotracheal intubation. Br J Anaesth 1998; 80: 4679[CrossRef][ISI][Medline]
88 Thwaites AJ, Edmends S, Tomlinson AA, Kendall JB, Smith I. Double-blind comparison of sevoflurane vs propofol and succinylcholine for tracheal intubation in children. Br J Anaesth 1999; 83: 4104
89 Thwaites AJ, Smith I. Sevoflurane for difficult tracheal intubation. Br J Anaesth 1998; 81: 1034
90 Troy AM, Hutchinson RC, Easy WR, Kenny GN. Tracheal intubating conditions using propofol and remifentanil target controlled infusions. Anaesthesia 2002; 57: 120412[CrossRef][ISI][Medline]
91 Wong AKH, Teoh GS. Intubation without muscle relaxant: an alternative technique for rapid tracheal intubation. Anaesth Intens Care 1996; 24: 22430[ISI][Medline]
92 Woods A, Grant S, Harten J, Noble JS, Davidson JAH. Tracheal intubating conditions after induction with propofol, remifentanil and lignocaine. Eur J Anaesth 1998; 16: 7148
93 Woods A, Grant S, Davidson A. Duration of apnoea with two different intubating doses of remifentanil. Eur J Anaesth 1999; 16: 6347[CrossRef][ISI][Medline]
94 Yakaitis RW, Blitt CD, Anguilo JP. End tidal halothane concentration for endotracheal intubation. Anesthesiology 1977; 47: 3868[ISI][Medline]
95 Yakaitis RW, Blitt CD, Anguilo JP. End tidal enflurane concentration for endotracheal intubation. Anesthesiology 1979; 50: 5961[ISI][Medline]
96 Yukioka H, Yoshimoto N, Nishimura K, Fujimuri M. Intravenous lidocaine as a suppressant of coughing during tracheal intubation. Anesth Analg 1985; 64: 118992[Abstract]
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