A SIMPLIFIED METHOD FOR ENDOTRACHEAL INTUBATION IN THE RAT

Endotracheal intubation in small laboratory animals is often necessary for survival experiments. Methods of airway control have included tra cheostomy, blind intubation, and intubation under direct vision. Most of these methods are unsatisfactory and associated with high failure a nd complication rate. We developed an easy method of endotracheal intu bation in the rat that requires simple material that is easily availab le to any research facility. The animals were anesthetized with pentob arbital sodium, the tongue was pulled out, and an otoscope was introdu ced into the oropharynx. By direct vision, a guide wire was inserted i nto the trachea and a 16-gauge intravenous catheter was glided over th e wire. The first group of 70 rats underwent left thoracotomy with end otracheal intubation and mechanical ventilation at our laboratory as p art of a study on isolated lung perfusion. The second group of five ra ts was anesthetized with pentobarbital, and a left carotid catheter an d an endotracheal tube were inserted. Animals were ventilated with 100 % O-2. Arterial blood gases were sampled before intubation, 30 min aft er ventilation, and 60 min after extubation. In the first group, 94.3% (66 of 70) of the animals survived surgery and mortality was not dire ctly related to the intubation and/or ventilation. All five animals of the second group survived the procedure to be extubated. Arterial PO2 before intubation, 30 min after intubation and ventilation, and 60 mi n after extubation was 77.1 +/- 8.5, 465.0 +/- 55.6, and 98.9 +/- 12.8 Torr, respectively. PCO2 at the same time points was 42.5 +/- 10.1, 3 5.1 +/- 6.3, and 32.7 +/- 6.5 Torr, respectively. This is an easy, fas t, and safe method for endotracheal intubation that will be useful to investigators in the cardiopulmonary physiology field.