A pilot study evaluating the use of cervical ultrasound to confirm endotracheal intubation in dogs

To assess the accuracy and usability of cervical ultrasound as a means to confirm endotracheal (ET) intubation in dogs.

Randomized pilot study.

University teaching hospital.

Six recently euthanized cadaver dogs.

Endotracheal and esophageal intubations were randomly performed. The investigators performing the ultrasound examinations were blinded to the type of intubation. Ultrasound examinations were performed in right and left lateral recumbency. The time taken to obtain the images was recorded.

The sensitivity, specificity, positive predictive value, and negative predictive value with their correspondent 95% confidence intervals (CI) were 91.7% (CI, 82.7-96.7), 72.7% (CI, 60.4-84.0%), 78.6% (CI, 68.3-86.8%), and 88.9% (CI, 77.4-95.8%), respectively. The overall test accuracy with its correspondent 95% CI was 82.8% (CI, 75.4-88.1%). The mean time for confirmation with ultrasound was 20.2 seconds (standard deviation, 14.3 s). Cervical ultrasound was significantly more accurate at recognizing ET intubations than esophageal intubations (odds ratio, 4.52; 95% CI, 1.43-14.27; P = 0.010). There was a significant relationship between increase in body weight and accuracy, indicating that the test is more accurate in larger dogs (odds ratio, 1.04; 95% CI, 1.00-1.08; P = 0.042).

Cervical ultrasound has high sensitivity and moderate specificity for ET intubation, and may be a useful tool to confirm ET intubation in dogs.