Videolaryngoscopy versus direct laryngoscopy for endotracheal intubation of obese patients: A prospective randomized trial.

BACKGROUND

Obese patients present challenging airway conditions, including reduced functional residual capacity and rapid desaturation during apnoea. Videolaryngoscopy improves glottic visualisation, but evidence comparing it with direct laryngoscopy in bariatric patients managed by experienced anaesthesiologists remains limited. We conducted a prospective randomised trial comparing these techniques.

METHODS

256 adult patients (BMI > 35 kg/m²) were randomised to intubation with a standard Macintosh laryngoscope or a hyperangulated videolaryngoscope (INSIGHT iS3-L), with a stylet routinely used in the videolaryngoscopy group. All received a standardised opioid-free anaesthesia protocol. The primary outcome was time to intubation (TOF = 0 to capnographic confirmation). Secondary outcomes included first-attempt success rate, number of intubation attempts, and bougie use.

RESULTS

Overall intubation success was achieved in all 256 patients; however, 4 patients (3.1%) in the Macintosh group required conversion to videolaryngoscopy as rescue. Median time to intubation was significantly shorter in the Macintosh group (35 [IQR 30-47.5] s vs 46 [IQR 35-62] s; P < .001), a difference partly attributable to operator familiarity and unlikely to be clinically relevant given comparable safety outcomes. No significant differences were observed in first-attempt success, intubation attempts, or bougie use. No airway injury or oxygen desaturation below 90% occurred; one prolonged Macintosh-group intubation was associated with peri-intubation bradycardia and hypotension. Neither Mallampati classification nor neck circumference > 43-44 cm reliably predicted intubation difficulty.

CONCLUSIONS

In this single-centre study of selected obese patients managed by experienced anaesthesiologists, direct laryngoscopy achieved shorter intubation times than a hyperangulated videolaryngoscope with comparable safety outcomes; however, the 11-second difference in median times is unlikely to be clinically relevant. The 3.1% conversion rate underscores that videolaryngoscopy must always be immediately available. Videolaryngoscopy remains essential in anticipated difficult airway management.