Comparison of blind intubation and a smartphone-based endoscope-assisted intubation in rabbits.

OBJECTIVE: To compare between blind and smartphone-based endoscope-assisted techniques for endotracheal intubation in rabbits. STUDY DESIGN: Prospective clinical study. ANIMALS: A total of 34 rabbits. METHODS: Rabbits were assigned to four groups: intubation by a veterinary anesthesiologist (VA) or an exotic pet medicine specialist (EPS) using blind or endoscope-assisted techniques. Propofol dose, number of attempts until successful intubation, total time for intubation, duration of the successful attempt and occurrence of lingual cyanosis/laryngeal lesions were recorded. Data were analyzed by t test, Wilcoxon-Mann-Whitney U test or chi-square test. Pearson correlation for body weight was performed. RESULTS: The success rate of blind intubation was 88.9% and 77.8% for VA and EPS, respectively. Propofol dose, total and median number of attempts, total time for intubation and duration of the successful attempt were 3.1 (0-6.2) mg kg-1, 19, 2 (1-5), 79 ± 65 and 30 ± 20 seconds for VA and 1.5 (0-4.5) mg kg-1, 24, 3 (1-5), 136 ± 92 and 38 ± 16 seconds for EPS. The success rate of endoscope-assisted intubation was 87.5% for both operators. Propofol dose, total and median number of attempts, total time for intubation and duration of the successful attempt were 2.5 (1.3-7.4) mg kg-1, 22, 3 (1-5), 170 (65-368) and 46 (22-150) seconds for VA and 3.2 (0-6) mg kg-1, 11, 1 (1-4), 56 (27-432) and 55 (26-79) seconds for EPS. VA performed blind intubation more quickly, propofol dose was lower and cyanosis was less frequent than in the endoscope-assisted group. CONCLUSIONS AND CLINICAL RELEVANCE: Both techniques were reliable for rabbit endotracheal intubation. Best results were achieved when the operator was experienced in the technique. The smartphone-based endoscope is a useful aid for rabbit intubation.

Ultrasound-guided superficial serratus plane block in dog cadavers: an anatomical evaluation and volume dispersion study.

OBJECTIVE: To evaluate the anatomy of the serratus plane in dogs to establish the optimal landmarks for a superficial serratus plane (SSP) block and evaluate ropivacaine-methylene blue solution dispersion with three volumes of injection. STUDY DESIGN: Prospective experimental cadaveric study. ANIMALS: A formaldehyde solution-preserved dog cadaver and 15 frozen/thawed adult dog cadavers. METHODS: The thoracic wall of the formaldehyde-preserved cadaver was dissected. An SSP injection was performed on each hemithorax of the cadavers, with the ultrasound transducer placed over the fourth and fifth ribs, at the level of the shoulder joint. A needle was inserted in-plane in a caudocranial direction until it could be visualized between the serratus ventralis thoracis and latissimus dorsi muscles. Dog cadavers were injected with a ropivacaine-methylene blue solution at 0.3, 0.6 and 1.0 mL kg-1 and were dissected to determine the spread of the dye. RESULTS: The thoracic wall muscles identified in the formalinized cadaver were the cutaneous trunci, latissimus dorsi, external abdominal oblique, serratus ventralis thoracis, scalenus, serratus dorsalis cranialis and external intercostal. The nerves identified in the SSP included the lateral cutaneous branches of intercostal nerves, intercostobrachial nerves and long thoracic nerve. The solution was successfully injected at the SSP in 26 of 29 (89.7%) attempts. Dermatomal dye spread, median (range), was 4 (3-6), 4 (2-5) and 5 (4-8) for 0.3, 0.6 and 1.0 mL kg-1, respectively, with no significant difference among them. CONCLUSIONS AND CLINICAL RELEVANCE: Injections for an SSP block were easily performed under ultrasound guidance, using the fourth and fifth ribs at the level of the shoulder joint as reference landmarks. An injected volume of 0.3 mL kg-1 may be sufficient for hemithorax analgesia in dogs. Further studies in dogs are required to determine the utility of this technique.