Evaluation of a rapid sequence induction technique in dogs with or without rocuronium

To determine, using a rapid sequence induction (RSI) technique, whether rocuronium improves the quality and speed of endotracheal intubation in healthy dogs.

Randomized, crossover, experimental study.

Six adult intact male Beagles (12.3 ± 0.4 kg).

Dogs were premedicated with intravenous acepromazine (0.03 mg kg^-1) and hydromorphone (0.1 mg kg^-1). Ten minutes later, anesthesia was induced with intravenous propofol (2 mg kg^-1 over 5 seconds), followed by saline (0.06 mL kg^-1, CT group) or rocuronium (0.6 mg kg^-1, RT group), with orotracheal intubation attempted after 45 seconds. Intubation time (IT) and conditions (IC) were assessed. PaO₂, PaCO₂, arterial blood pH and serum cortisol were obtained before and after RSI. After endotracheal intubation, saline (0.04 mL kg^-1) or sugammadex (4 mg kg^-1) were administered intravenously in CT or RT groups, respectively. Spontaneous ventilation restoration was noted.

The IT was 54.3 ± 6.9 (mean ± SD) and 57.8 ± 5.2 seconds for CT and RT, respectively (p = 0.385). All laryngoscopies indicated good IC in both treatment groups. Heart rate was lower in CT group than in RT group (66 ± 16 versus 103 ± 39 beats minute^-1, p = 0.016). PaCO₂, pH, PaO₂ and cortisol did not differ between treatments. Compared with baseline, PaCO₂ increased from 47.7 ± 6.2 to 58.8 ± 5.8 (p < 0.001) and pH decreased from 7.35 ± 0.04 to 7.28 ± 0.04 (p = 0.003), independent of treatment. Dogs in both treatment groups returned to spontaneous ventilation within 30 seconds of RSI.

RSI resulted in respiratory acidosis without hypoxemia or increased cortisol. Rocuronium did not improve IT or IC. Spontaneous ventilation was observed immediately after administering saline or sugammadex. The co-administration of rocuronium showed no clinical benefits over propofol alone in RSI in healthy dogs.