We studied intubating conditions and hemodynamic changes during endotracheal intubation employing either Bonfils intubating fiberscope or the conventional Macintosh laryngoscopy in 80 healthy patients candidates for elective surgery requiring endotracheal intubation. We omitted neuromuscular blocking drugs from the induction regimen.

BACKGROUND:

Neuromuscular blocking drugs (NMBDs) are believed to be the dominating antigens causing bronchospasm and anaphylaxis during anaesthesia. Avoidance of these drugs, however, renders compromised intubating conditions and higher morbidity with conventional Macintosh laryngoscopy. Thus, we compared Macintosh laryngoscopy with Bonfils intubation fibrescope without administering NMBDs.

METHODS:

Eighty male and female patients scheduled for elective surgery, aged 15 to 60 years, ASA class II or I, non-obese, with lower risk for difficult intubation were enrolled in this study. They were randomly allocated into the Bonfils group or the Macintosh group (40 each). Following adequate hydration and preoxygenation, midazolam 0.05 mg kg-1 was administered, followed by alfentanil 20 µg kg-1, lidocaine 1.5 mg kg-1, and propofol 2 mg kg-1 intravenously. Tracheal intubation was then carried out using Bonfils intubation fibrescope (Bonfils group) or employing conventional Macintosh laryngoscopy (Macintosh group). The primary outcome measure was the intubating condition, with mean arterial blood pressure and heart rate as secondary outcomes.

Inclusion Criteria:

• American Society of Anesthesiology (ASA) physical status was class I or II
• body mass index (BMI) < 30
• ability to assume the 'sniffing' position

Exclusion Criteria:

• smokers
• drug users
• pregnant
• expected to present difficult intubation
• history of oesophageal reflux
• any systemic or airway disease
• known allergy to the protocol medications