Optimal effect-site concentration of remifentanil for preventing cough during emergence from sevoflurane-remifentanil anaesthesia

This randomised, double-blinded, controlled trial was designed to identify the optimal dose of remifentanil for cough suppression without adverse effects during emergence from sevoflurane-remifentanil anaesthesia for thyroidectomy. One hundred and four patients were randomly assigned to maintain target effect-site concentrations of remifentanil at 0 (control group), 1.0 (remifentail 1 group), or 1.5 ng.ml(-1) (remifentanil 1.5 group) during emergence. The incidence of coughing was lower in the remifentanil 1.5 group (31%) than in the control group (74%) or remifentanil 1 group (63%) (p = 0.0004). In addition, the severity of coughing during extubation was lower in the remifentanil 1.5 group (median (IQR [range]) 0 (0-1 [0-1]) than in the control group (1 (0-2 [0-3])) and remifentanil 1 group (1 (0-2 [0-3])) (p = 0.004). Haemodynamic changes were reduced, but emergence time and stay in the post-anaesthesia care unit was prolonged in the remifentanil 1.5 group. Maintaining the remifentanil effect-site concentration at 1.5 ng.ml(-1) during emergence from sevoflurane-remifentanil anaesthesia reduces the incidence and severity of coughing without serious adverse events and may provide haemodynamic stability in patients undergoing thyroidectomy. However, awakening may be delayed.

[Changes in arterial pressure and heart rate during laryngeal mask insertion in hypertensive patients: comparison with endotracheal intubation]

The pressor response associated with laryngoscopy and endotracheal intubation may be harmful to patients with ischemic heart disease, hypertension or cerebrovascular disease. The Brain laryngeal mask airway can be inserted blindly and avoid the need for laryngoscopy. Our preliminary study compared the pressor response of tracheal intubation (T group) with that of laryngeal mask insertion (L group) in 19 and 33 hypertensive patients respectively. We also divided the patients of L group into sub-groups I (n = 16) and II (n = 17). All patients in T group and sub-group I were induced with fentanyl, thiopentone and succinylcholine while in subgroup II patients were induced with the same dosage of thiopentone and succinylcholine without fentanyl. The changes of blood pressure and heart rate exhibited a similar but attenuated pattern of response with laryngeal mask insertion in comparison with tracheal intubation. We also found no significant difference in pressor response between sub-group I and sub-group II in L group. In sum, laryngeal mask insertion may therefore offer some advantages over tracheal intubation in the anesthetic management of hypertensive patients in whom less pressor response is of particular concern.

[Clinical assessment of laryngeal mask airway in general anesthesia with spontaneous breathing]

The laryngeal mask airway (LMA) is a new form of oropharyngeal airway that provides an alternative to endotracheal intubation and face mask anesthesia in certain cases. Once the patient is adequately anesthetised, it can be inserted blindly without recourse to laryngoscopy. The advantages over standard mask anesthesia are: better airway control, minimal leakage of anesthetic gases, and it frees the anesthetist's hands, as no mandibular support is needed. LMA does not guarantee against the risk of aspiration and it is not recommended for use in patients who may have risk of gastric regurgitation. Our preliminary study revealed that a clear and clinical satisfactory airway was obtained in 98.2% of patients. According to the intraoperative respiratory minute volume and arterial blood gases, the patency of the airway did not deteriorate during the course of the anesthesia. Blood pressure and heart rate were compared on induction in group I and II. Succinylcholine 1 mg/kg, thiopentone 4-6 mg/kg and fentanyl 2 micrograms/kg were used in group I while using the same dosage of succinylcholine and thiopentone without fentanyl for group II. We found no significant differences in vital signs between the two groups.