Perioperative lung ultrasonography in healthy horses undergoing general anesthesia for elective surgery.

Background: Lung ultrasound (LUS) is poorly evaluated in horses, especially perioperatively.

Objectives: (1) Describe LUS findings in healthy horses before and after general anesthesia (GA), (2) evaluate if GA induces ultrasonographic changes in healthy horses, (3) suggest a LUS scoring system, (4) identify horse variables that are associated to LUS changes after anesthesia.

Animals: Twenty-five healthy adult horses undergoing elective surgery.

Methods: Prospective hypothesis-driven observational study. LUS findings were recorded before anesthesia, 5 minutes in recovery, 15 minutes, 2H, 3H, 4H, 6H, and 24H after anesthesia in 8 lung regions. Clinical data were collected perioperatively.

Results: There was a significant increase in amount of I-lines (10.8 ± 8.7 vs 15.28 ± 8.19), B-lines (3.2 ± 3.5 vs 8.72 ± 4.86), and coalescent B-lines (0.04 ± 0.2 vs 1.12 ± 1.45) after anesthesia compared to before anesthesia, and a significantly higher LUS score 2H after anesthesia (4.92 ± 8.40) compared to before anesthesia (0.9 ± 1.8; P = .02). The maximal LUS score after anesthesia was correlated to total procedure time (Pearson r = 0.4, P = .05; Spearman r = 0.44, P = .03) and was significantly higher in horses with abnormal cardiorespiratory values during anesthesia (P = .005).

Conclusions: LUS changes can be induced by GA in healthy horses. This study did not investigate if and which LUS findings indicate lesions, however, this information can aid clinicians to identify pulmonary complications after anesthesia.