Anaesthesia, 1991, Volume 46, pages 3 12-3 13
Intubation with propofol augmented with intravenous lignocaine
D. Mulholland, MB, BCh, FFARCS, FFARCSI, Registrar, R. J. T. Carlisle, MB, BCh, FFARCSI, Consultant, Daisy Hill Hospital, Newry, Co. Down, Northern Ireland.
Summary Sixty patients of ASA grade 1 and aged 18 to 55 years were admitted to a double-blind study. Anaesthesia was induced with propofo12.5 mglkg after intravenous pretreatment with lignocaine 1.5 mglkg or a similar volume of isotonic saline. The quality of subsequent tracheal intubation was graded and the pressor response to tracheal intubation assessed. There were no signijicant differences between treatment groups.
Key words Anaesthetics, intravenous; propofol, lignocaine. Intubation, tracheal; complications.
Depression of laryngeal reflexes has been reported following induction of anaesthesia with propofol.’ Keaveney et al.’ achieved a 95% success rate using propofol alone for induction and tracheal intubation. De Grood et a/.3augmented propofol with a topical lignocaine spray to allow intubation without muscle relaxants. Yukioka et aL4 showed. that intravenous lignocaine effectively suppressed the cough reflex after intubation under deep halothane anaesthesia. The aim of this study was to compare the quality of tracheal intubation after induction of anaesthesia with propofol in patients who received intravenous lignocaine pretreatment with that in patients who received propofol alone. Method
The study was approved by the regional ethics committee. Sixty patients aged between 18 and 55 years and scheduled to undergo elective general or gynaecological surgery which required tracheal intubation were admitted to the study. A11 were graded as ASA 1. Patients with dental crowns, a past history of drug sensitivity and those assessed as presenting potential difficulties for tracheal intubation were not studied. The study was conducted in a double-blind fashion. Informed consent was obtained in all cases and the patients were allocated randomly to one of two groups. All patients were premedicated with diazepam 10mg orally one hour before operation. Blood pressure was recorded automatically (Critikon, Dinamap) in the anaesthetic room and oxygen saturation was measured by pulse oximetry. A 20-gauge cannula was sited in a large antecubital vein. The lungs were pre-oxygenated. Only one anaesthetist (alternately R.C. and D.M.) was aware of the group to which the patient was allocated. He injected either lignocaine 1.5 mg/kg or an identical volume of 0.9% saline over 30 seconds, timed by a stopwatch. All patients then received propofol 2.5 mg/kg over 20 seconds. After a further 40 seconds, when verbal response and eyelash reflex were lost, tracheal intubation was attempted by the other anaesthetist. The quality of intubation was graded by the second anaesthetist according to the following scale: excellent; Accepted 11 July 1990.
relaxed jaw, cords abducted, no movement on intubation: good, relaxed jaw, cords abducted, some movement on intubation: unsatisfactory, difficulty in opening mouth, cords moving or adducted, movement on intubation: failure, laryngoscopy impossible, intubation abandoned. Failed intubation prompted ventilation of the lungs with 100% oxygen for a further 30 seconds before laryngoscopy was re-attempted. If intubation again proved impossible anaesthesia was deepened with volatile agents and a neuromuscular blocker was administered before intubation was attempted again. Successful intubation was followed by administration of an appropriate anaesthetic, and a neuromuscular blocker was given if required. A decrease in oxygen saturation during induction was treated by ventilation with 100% oxygen through the facemask. Mean arterial blood pressure was measured immediately before laryngoscopy, and one minute after tracheal intubation. The ages and weights of patients in the two groups were compared using the unpaired Student’s t-test. Sex distribution was analysed by the Chi-squared test and the intubation quality with the Mann-Whitney U-test. Blood pressure measurements were compared within groups using the paired t-test and between groups using the unpaired f-test. Results
Two groups of 30 patients each were studied. There were no significant differences between groups in respect of age or weight (Table I), but there were significantly more Table 1. Mean (SD) age and weight, and sex distribution, of patients who received pretreatment with lignocaine or saline. There were no significant differences.
Age; years Weight; kg M:F
Lignocaine
Saline
34.4 (10.7) 69.4 (10.1) 11:19
32.5 (5.5) 68.2 (9.8) 7:23
Forum Table 2. Quality of intubation assessed by anaesthetist in patients who received pretreatment with lignocaine or saline. Figures indicate number of patients. There were no significant differences.
Grade Excellent Good Unsatisfactory Failed
Lignocaine
Saline
14 6 2 8
9 I 4 10
Table 3. Mean (SD) of mean arterial pressures (mmHg) immediately before laryngoscopy and one minute after tracheal intubation in patients who received pretreatment with lignocaine or saline. There were no significant differences. ~~~~
Before laryngoscopy After intubation
~
Lignocaine
Saline
95.1 (15.8) 98.2 (14.2)
91.5 (10.9) 92.0 (14.7)
female patients in the pretreatment group. Excellent intubation conditions were recorded in 30% of the control group and 46% of those who received lignocaine pretreatment; this difference was not statistically significant (Table 2). None of the patients in whom tracheal intubation was unsuccessful at the first attempt could be intubated after a 30-second delay. There were no significant differences between the pre-intubation and post-intubation blood pressures in either group (Table 3), and no significant differences in blood pressures between groups. Discussion
Previous studies have shown that propofol obtunds laryngeal reflexes and that laryngoscopy and intubation are possible at safe induction doses.’,2Lignocaine is known to reduce tracheal irritability when injected intravenously and seems a logical pretreatment when propofol is used in this way! Keaveney et al.’ used the same induction dose as ourselves but slightly different intubation criteria; they reported that intubating conditions were ideal in 60% of patients.
313
Yukioka et aL4reported a dose-dependent suppression of coughing by intravenous lignocaine. However, in a pilot study we found that doses greater than 1.5 mg/kg caused a tingling sensation which would have defeated the doubleblind design of our study. The hypertensive response to laryngoscopy and intubation was not evident in either group. Intravenous lignocaine pretreatment has been recommended for the control of this reflex following induction with thiopentone but did not seem to offer any advantage in this study. Thus an induction dose of propofol 2.5 mg/kg seems to result in cardiovascular stability during subsequent laryngoscopy and intubation although we measured blood pressure on only two occasions. This effect was evident in patients in whom intubating conditions were unsatisfactory or in whom intubation was unsuccessful. It appears that movement and coughing during intubation after induction with propofol is not related to an increase in blood pressure. This technique may have a place in the induction and intubation of patients in whom nondepolarising muscle relaxants are contraindicated (for example patients with myasthenia gravis) or when the anaesthetist wishes to avoid suxamethonium. It appears to offer cardiovascular stability regardless of the amount of movement during intubation. However, it does not seem reliable or predictable enough for routine use as there was an overall failure rate of 30.6%. References 1. MCKEATINGK, BALI IM, DUNDEE JW. The effects of thiopentone and propofol on upper airway integrity. Anaesthesia 1988; 43: 63840. 2. KEAVENY JP, KNELLPJ. Intubation under induction doses of propofol. Anaesthesia 1988; 43 (Suppl.): 8&1. 3. DE GRWD PMRM, VANEGMOND J, WEERINGM VANDE, VAN BEEMHB, BWIJ LHDJ, CRULJF. Lack of effects of emulsified propofol (‘Diprivan’) on vecuronium pharmacodynamics-preliminary results in man. Postgraduate Medical Journal 1985; 61 (Suppl. 3): 28-30. 4. YUKIOKAH, YOSHIMOTO N, NISHIMURAK, FUJIMORI M. Intravenous lidocaine as a suppresant of coughing during tracheal intubation. Anesthesia and Analgesia 1985: 64: 1189-92. 5. HAMILLJF, BEDFORDRF, WEAVERDC, COLOHANAR. Lidocaine before endotracheal intubation: intravenous or laryngotracheal? Anesthesiology 1981: 55; 578-81.
Intubation with propofol augmented with intravenous lignocaine
D. Mulholland, MB, BCh, FFARCS, FFARCSI, Registrar, R. J. T. Carlisle, MB, BCh, FFARCSI, Consultant, Daisy Hill Hospital, Newry, Co. Down, Northern Ireland.
Summary Sixty patients of ASA grade 1 and aged 18 to 55 years were admitted to a double-blind study. Anaesthesia was induced with propofo12.5 mglkg after intravenous pretreatment with lignocaine 1.5 mglkg or a similar volume of isotonic saline. The quality of subsequent tracheal intubation was graded and the pressor response to tracheal intubation assessed. There were no signijicant differences between treatment groups.
Key words Anaesthetics, intravenous; propofol, lignocaine. Intubation, tracheal; complications.
Depression of laryngeal reflexes has been reported following induction of anaesthesia with propofol.’ Keaveney et al.’ achieved a 95% success rate using propofol alone for induction and tracheal intubation. De Grood et a/.3augmented propofol with a topical lignocaine spray to allow intubation without muscle relaxants. Yukioka et aL4 showed. that intravenous lignocaine effectively suppressed the cough reflex after intubation under deep halothane anaesthesia. The aim of this study was to compare the quality of tracheal intubation after induction of anaesthesia with propofol in patients who received intravenous lignocaine pretreatment with that in patients who received propofol alone. Method
The study was approved by the regional ethics committee. Sixty patients aged between 18 and 55 years and scheduled to undergo elective general or gynaecological surgery which required tracheal intubation were admitted to the study. A11 were graded as ASA 1. Patients with dental crowns, a past history of drug sensitivity and those assessed as presenting potential difficulties for tracheal intubation were not studied. The study was conducted in a double-blind fashion. Informed consent was obtained in all cases and the patients were allocated randomly to one of two groups. All patients were premedicated with diazepam 10mg orally one hour before operation. Blood pressure was recorded automatically (Critikon, Dinamap) in the anaesthetic room and oxygen saturation was measured by pulse oximetry. A 20-gauge cannula was sited in a large antecubital vein. The lungs were pre-oxygenated. Only one anaesthetist (alternately R.C. and D.M.) was aware of the group to which the patient was allocated. He injected either lignocaine 1.5 mg/kg or an identical volume of 0.9% saline over 30 seconds, timed by a stopwatch. All patients then received propofol 2.5 mg/kg over 20 seconds. After a further 40 seconds, when verbal response and eyelash reflex were lost, tracheal intubation was attempted by the other anaesthetist. The quality of intubation was graded by the second anaesthetist according to the following scale: excellent; Accepted 11 July 1990.
relaxed jaw, cords abducted, no movement on intubation: good, relaxed jaw, cords abducted, some movement on intubation: unsatisfactory, difficulty in opening mouth, cords moving or adducted, movement on intubation: failure, laryngoscopy impossible, intubation abandoned. Failed intubation prompted ventilation of the lungs with 100% oxygen for a further 30 seconds before laryngoscopy was re-attempted. If intubation again proved impossible anaesthesia was deepened with volatile agents and a neuromuscular blocker was administered before intubation was attempted again. Successful intubation was followed by administration of an appropriate anaesthetic, and a neuromuscular blocker was given if required. A decrease in oxygen saturation during induction was treated by ventilation with 100% oxygen through the facemask. Mean arterial blood pressure was measured immediately before laryngoscopy, and one minute after tracheal intubation. The ages and weights of patients in the two groups were compared using the unpaired Student’s t-test. Sex distribution was analysed by the Chi-squared test and the intubation quality with the Mann-Whitney U-test. Blood pressure measurements were compared within groups using the paired t-test and between groups using the unpaired f-test. Results
Two groups of 30 patients each were studied. There were no significant differences between groups in respect of age or weight (Table I), but there were significantly more Table 1. Mean (SD) age and weight, and sex distribution, of patients who received pretreatment with lignocaine or saline. There were no significant differences.
Age; years Weight; kg M:F
Lignocaine
Saline
34.4 (10.7) 69.4 (10.1) 11:19
32.5 (5.5) 68.2 (9.8) 7:23
Forum Table 2. Quality of intubation assessed by anaesthetist in patients who received pretreatment with lignocaine or saline. Figures indicate number of patients. There were no significant differences.
Grade Excellent Good Unsatisfactory Failed
Lignocaine
Saline
14 6 2 8
9 I 4 10
Table 3. Mean (SD) of mean arterial pressures (mmHg) immediately before laryngoscopy and one minute after tracheal intubation in patients who received pretreatment with lignocaine or saline. There were no significant differences. ~~~~
Before laryngoscopy After intubation
~
Lignocaine
Saline
95.1 (15.8) 98.2 (14.2)
91.5 (10.9) 92.0 (14.7)
female patients in the pretreatment group. Excellent intubation conditions were recorded in 30% of the control group and 46% of those who received lignocaine pretreatment; this difference was not statistically significant (Table 2). None of the patients in whom tracheal intubation was unsuccessful at the first attempt could be intubated after a 30-second delay. There were no significant differences between the pre-intubation and post-intubation blood pressures in either group (Table 3), and no significant differences in blood pressures between groups. Discussion
Previous studies have shown that propofol obtunds laryngeal reflexes and that laryngoscopy and intubation are possible at safe induction doses.’,2Lignocaine is known to reduce tracheal irritability when injected intravenously and seems a logical pretreatment when propofol is used in this way! Keaveney et al.’ used the same induction dose as ourselves but slightly different intubation criteria; they reported that intubating conditions were ideal in 60% of patients.
313
Yukioka et aL4reported a dose-dependent suppression of coughing by intravenous lignocaine. However, in a pilot study we found that doses greater than 1.5 mg/kg caused a tingling sensation which would have defeated the doubleblind design of our study. The hypertensive response to laryngoscopy and intubation was not evident in either group. Intravenous lignocaine pretreatment has been recommended for the control of this reflex following induction with thiopentone but did not seem to offer any advantage in this study. Thus an induction dose of propofol 2.5 mg/kg seems to result in cardiovascular stability during subsequent laryngoscopy and intubation although we measured blood pressure on only two occasions. This effect was evident in patients in whom intubating conditions were unsatisfactory or in whom intubation was unsuccessful. It appears that movement and coughing during intubation after induction with propofol is not related to an increase in blood pressure. This technique may have a place in the induction and intubation of patients in whom nondepolarising muscle relaxants are contraindicated (for example patients with myasthenia gravis) or when the anaesthetist wishes to avoid suxamethonium. It appears to offer cardiovascular stability regardless of the amount of movement during intubation. However, it does not seem reliable or predictable enough for routine use as there was an overall failure rate of 30.6%. References 1. MCKEATINGK, BALI IM, DUNDEE JW. The effects of thiopentone and propofol on upper airway integrity. Anaesthesia 1988; 43: 63840. 2. KEAVENY JP, KNELLPJ. Intubation under induction doses of propofol. Anaesthesia 1988; 43 (Suppl.): 8&1. 3. DE GRWD PMRM, VANEGMOND J, WEERINGM VANDE, VAN BEEMHB, BWIJ LHDJ, CRULJF. Lack of effects of emulsified propofol (‘Diprivan’) on vecuronium pharmacodynamics-preliminary results in man. Postgraduate Medical Journal 1985; 61 (Suppl. 3): 28-30. 4. YUKIOKAH, YOSHIMOTO N, NISHIMURAK, FUJIMORI M. Intravenous lidocaine as a suppresant of coughing during tracheal intubation. Anesthesia and Analgesia 1985: 64: 1189-92. 5. HAMILLJF, BEDFORDRF, WEAVERDC, COLOHANAR. Lidocaine before endotracheal intubation: intravenous or laryngotracheal? Anesthesiology 1981: 55; 578-81.
