Intubating conditions and adverse events during sevoflurane induction in infants.

BACKGROUND: The aim of this study was to compare intubating conditions and adverse events after sevoflurane induction in infants, with or without the use of rocuronium or alfentanil. METHODS: Seventy-five infants, aged 1-24 months, undergoing elective surgery under general anaesthesia were randomly assigned to receive 8% sevoflurane with either placebo (i.v. saline 0.5 ml kg⁻¹), rocuronium (0.3 mg kg⁻¹), or alfentanil (20 µg kg⁻¹). The primary outcome measure was intubating conditions evaluated 90 s after test drug injection by an anaesthetist unaware of the patient's group. The secondary outcome criteria were respiratory (Sp(O2) <90%, laryngospasm, closed vocal cords preventing intubation, bronchospasm) and haemodynamic adverse events (heart rate and mean arterial pressure variations ≥30% control value). RESULTS: Intubating conditions were significantly better in the rocuronium group, with clinically acceptable intubating conditions in 92%, vs 70% in the alfentanil group and 63% in the placebo group (P=0.044). Adverse respiratory events were significantly less frequent in the rocuronium group: 0% vs 33% in the placebo group and 30% in the alfentanil group (P=0.006). Haemodynamic adverse events were more frequent in the alfentanil group: 48% vs 7% in the placebo group and 16% in the rocuronium group (P=0.0019). CONCLUSIONS: In 1- to 24-month-old infants, the addition of 0.3 mg kg⁻¹ rocuronium to 8% sevoflurane improved intubating conditions and decreased the frequency of respiratory adverse events. Alfentanil provided no additional benefit in this study.

Cuff compliance of pediatric and adult cuffed tracheal tubes: an experimental study.

BACKGROUND: Tracheal mucosal damage related to tracheal intubation has been widely described in pediatric and adult patients. High volume-low pressure cuffs (HVLPC) are being advertised as safe to avoid this particularly unpleasant complication. Compliances of these supposed pediatric and adult HVLPC are not mentioned by manufacturers and still remain unknown. METHODS: The compliance of HVLPC was measured in vitro and defined as the straight portion of the pressure-volume curve. Cuff pressure was measured after incremental 0.1 ml filling volumes of air for sizes 3.0-8.0 of internal diameter of Rüsch and Mallinckrodt tracheal tubes. Compliances were assessed in air and in a rigid tube. The filling volume to achieve a 25-mmHg intracuff pressure was also measured. RESULTS: In air, each 0.1 ml step almost linearly increased cuff pressure by 1 mmHg (size 8.0) to 9 mmHg (size 3). In air, the volume needed to maintain a cuff pressure < 25 mmHg was small for sizes 3-5.5 (0.35-2 ml). The 25 mmHg inflated cuff volume and compliance were decreased within a rigid tube, especially for adult sizes. In a rigid tube simulating a trachea, the compliances of almost every Rüsch tracheal tube were statistically higher than those of the Mallinckrodt. CONCLUSION: We conclude that the tested tracheal tube cuffs have low compliance and cannot be defined as high volume-low pressure.

Intracuff pressure and tracheal morbidity: influence of filling with saline during nitrous oxide anesthesia.

BACKGROUND: Diffusion of nitrous oxide into the cuff of the endotracheal tube results in an increase in cuff pressure. Excessive endotracheal tube cuff pressure may impair tracheal mucosal perfusion and cause tracheal damage and sore throat. Filling the cuff of the endotracheal tube with saline instead of air prevents the increase in cuff pressure due to nitrous oxide diffusion. This method was used to test whether tracheal morbidity is related to excess in tracheal cuff pressure during balanced anesthesia. METHODS: Fifty patients with American Society of Anesthesiologists physical status I or II were randomly allocated to two groups with endotracheal tube cuffs initially inflated to 20-30 cm H(2)O with either air (group A) or saline (group S). Anesthesia was maintained with isoflurane and nitrous oxide. At the time of extubation, a fiberoptic examination of the trachea was performed by an independent observer, and abnormalities of tracheal mucosa at the level of the cuff contact area were scored. Patients assessed their symptoms (sore throat, dysphagia, and hoarseness) at the time of discharge from the postanesthesia care unit and 24 h after extubation on a 101-point numerical rating scale. RESULTS: Cuff pressure increased gradually during anesthesia in group A but remained stable in group S. The incidence of sore throat was greater in group A than in group S in the postanesthesia care unit (76 vs. 20%) and 24 h after extubation (42 vs. 12%; P < 0.05). Tracheal lesions at time of extubation were seen in all patients of group A and in eight patients (32%) of group S (P < 0.05). CONCLUSION: Excess in endotracheal tube cuff pressure during balanced anesthesia due to nitrous oxide diffusion into this closed gas space causes sore throat that is related to tracheal mucosal erosion.