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Prevention of coughing upon emergence from anaesthesia: the indubitable effect of propofol.
- Pol Hans, Hugues Marechal, Vincent Bonhomme (7 April 2009)
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Cough During Emergence From Anaesthesia – Is Propofol, Remifentanil Or Lidocaine The Answer?
- Satya Krishna Ramachandran (1 April 2009)
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Pol Hans University Dpt of Anaesthesia and ICM, CHR Citadelle, Liege, Belgium, Hugues Marechal, Vincent Bonhomme
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We read with interest the letter of Ramachandran commenting on our paper entitled “Effect of propofol and sevoflurane on coughing in smokers and non-smokers awakening from general anaesthesia at the end of a cervical spine surgery”. We would like to thank Doctor Ramachadran for the interesting remarks and questions, which deserve a point by point reply. The first comment relates to the anti-tussive effect of remifentanil, whose effect-site concentrations at extubation could have favoured the propofol group. We acknowledge that a low dose of remifentanil has been recently shown by Aouad et al. to significantly reduce the incidence and the severity of coughing at extubation [1], although this finding is in contradiction with the results of a former study, which demonstrated that remifentanil can induce cough that is suppressed by lidocaine [2]. In the study published by Aouad, the infusion rate of remifentanil in the two groups was calculated on a body weight basis, without any information regarding effect-site concentrations of the opiate. In our study, the mean effect-site concentration of remifentanil at the time of tracheal extubation was higher in the propofol than in the sevoflurane group. Nevertheless, the logistic regression analysis clearly demonstrated that the effect of the residual concentration of remifentanil on the probability of coughing at extubation was far weaker than that of the hypnotic agents. In addition, the logistic regression also revealed that, in smokers anaesthetized with sevoflurane, the probability of coughing was the highest and was not influenced by the residual concentrations of either sevoflurane or remifentanil. The author of the letter mentions that sevoflurane is known to favour coughing due to its property to increase laryngeal reactivity [3]. This comment is in perfect agreement with the results of our study and should incite anaesthetists to prefer propofol to sevoflurane for anaesthesia maintenance in patients particularly at risk of coughing at extubation. However, as already discussed in our paper, this deleterious effect may not be the prerogative of sevoflurane only, as far as a study comparing airway responses during desflurane versus sevoflurane administration reported that cigarette smoking and not the choice of the halogenated anaesthetic significantly affects respiratory complications, including coughing [4]. The last comment is related to the fact that several techniques currently used to reduce coughing such as topical or intravenous administration of lidocaine were not employed in our study and that our patient population was particularly at risk of potentially dangerous complications related to coughing at emergence from anaesthesia. We first argue that none of the techniques used to prevent coughing and briefly described in the introduction section of our paper are fully reliable and can guarantee the absence of coughing [5]. In addition, some are not necessarily devoid of side effects. For example, topical lidocaine has long been known to reduce pharyngeal muscle activity, which is of great concern in surgical patients undergoing an anterior approach of the cervical spine [6]. Finally, we acknowledge that our patient population was particularly at risk, but this is the patient population we are dealing with every day in a neurosurgical department. By conducting our study, we aimed at determining the best anaesthetic regimen for those particular patients. We demonstrated a statistically lower incidence of severe coughing with propofol than with sevoflurane (6% versus 59%) in this particular setting. The incidence of 6 % in our propofol group was even lower than the 11 % incidence reported in the study of Venkatesan investigating the effect of topical or intravenous lidocaine [7]. We therefore definitely support propofol maintenance as a contributing factor to prevent severe coughing at emergence from anaesthesia. P. Hans, H. Marechal and V. Bonhomme References 1. Aouad MT, Al-Alami AA, Nasr VG, Souki FG, Zbeidy RA, Siddik-Sayyid SM. The effect of low-dose remifentanil on responses to the endotracheal tube during emergence from general anesthesia. Anesth Analg 2009; 108: 1157-60. 2. Kim JY, Park KS, Kim JS, Park SY, Kim JW. The effect of lidocaine on remifentanil-induced cough. Anaesthesia. 2008; 63: 495-8. 3. Valley RD, Freid EB, Bailey AG, Kopp VJ, Georges LS, Fletcher J, Keifer A. Tracheal extubation of deeply anesthetized pediatric patients: a comparison of desflurane and sevoflurane. Anesth Analg 2003; 96: 1320-4 4. McKay RE, Bostrom A, Balea MC, McKay WR. Airway responses during desflurane versus sevoflurane administration via a laryngeal mask airway in smokers. Anesth Analg 2006; 103: 1147-54. 5. Hohlrieder M, Tiefenthaler W, Klaus H, Gabl M, Kavakebi P, Keller C, Benzer A. Effect of total intravenous anaesthesia and balanced anaesthesia on the frequency of coughing during emergence from the anaesthesia. Br J Anaesth 2007; 99: 587-91. 6. Fogel RB, Malhotra A, Shea SA, Edwards JK, White DP. Reduced genioglossal activity with upper airway anesthesia in awake patients with OSA. J Appl Physiol 2000; 88: 1346-54. 7. Venkatesan T, Korula G. A comparative study between the effects of 4% endotracheal tube cuff lignocaine and 1.5 mg/kg intravenous lignocaine on coughing and hemodynamics during extubation in neurosurgical patients: a randomized controlled double-blind trial. J Neurosurg Anesthesiol 2006; 18: 230-4. Conflict of Interest:None declared |
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Satya Krishna Ramachandran, Assistant Professor University of Michigan
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Hans and colleagues compare coughing following propofol and sevoflurane based anesthesia in patients undergoing neck surgery [1]. The results strongly support the use propofol over sevoflurane in both smokers and non-smokers. However, some important questions remain. Firstly, the unequal distribution of remifentanil effect-site concentrations in the two groups at extubation favours the propofol group. In light of newer evidence that low dose remifentanil does indeed reduce the incidence and severity of coughing after general anesthesia [2], it could be argued that the final results of Hans’s study were related in part or whole to remifentanil’s anti-tussive effects. There are inadequate data in their paper to challenge this assumption. Secondly, it is well established that sevoflurane increases laryngeal reactivity, with coughing rates of 25% even after deep extubation technique [3]. Additionally, several techniques have been described in literature to reduce coughing at emergence, usually involving lidocaine, either topical or intravenous [4]. It is disappointing that Hans and colleagues have avoided these techniques, as this has undoubtedly increased the incidence of coughing in their study patients, while denying clinical users crucial data on the best approach to prevent coughing on emergence. In this context, it is surprising that they have chosen a study population at higher risk of potentially dangerous complications related to coughing at emergence from anaesthesia. A safer approach would have been to recruit patients at lower risk of neck haematoma formation due to severe coughing. In summary, although a propofol-remifentanil based anaesthetic is better than a sevoflurane- remifentanil based anaesthetic, it is probably more important to ensure that a baseline infusion of remifentanil or topical lidocaine is used in patients at high risk of complications due to emergence coughing. References: 1. Hans P, Marechal H, Bonhomme V. Effect of propofol and sevoflurane on coughing in smokers and non-smokers awakening from general anaesthesia at the end of a cervical spine surgery. Br J Anaesth 2008; 101: 731-7 2. Aouad MT, Al-Alami AA, Nasr VG, Souki FG, Zbeidy RA, Siddik-Sayyid SM. The Effect of Low-Dose Remifentanil on Responses to the Endotracheal Tube During Emergence from General Anesthesia. Anesth Analg 2009; 108: 1157-60 3. Valley RD, Freid EB, Bailey AG, et al. Tracheal Extubation of Deeply Anesthetized Pediatric Patients: A Comparison of Desflurane and Sevoflurane. Anesth Analg 2003; 96: 1320-4 4. Venkatesan T, Korula G. A comparative study between the effects of 4% endotracheal tube cuff lignocaine and 1.5 mg/kg intravenous lignocaine on coughing and hemodynamics during extubation in neurosurgical patients: a randomized controlled double-blind trial. Journal of neurosurgical anesthesiology 2006; 18: 230-4 Conflict of Interest:None declared |
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