AUTHOR=Rodrigues Renata R. , Ambrósio Aline M. , Engbruch Aline M. , Gonçalves Lucas A. , Villela Paula A. , Sanchez Ana F. , Fantoni Denise T. TITLE=Intraoperative Protective Mechanical Ventilation in Dogs: A Randomized Clinical Trial JOURNAL=Frontiers in Veterinary Science VOLUME=9 YEAR=2022 URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2022.842613 DOI=10.3389/fvets.2022.842613 ISSN=2297-1769 ABSTRACT=Objective

To evaluate gas exchange, respiratory mechanics, and hemodynamic impact of mechanical ventilation with low tidal volume (VT) in dogs with the use of positive end-expiratory pressure (PEEP) or preceded by alveolar recruitment maneuver (ARM).

Study Design

Prospective randomized clinical trial.

Animals

Twenty-one healthy client-owned mesocephalic healthy dogs, 1–7 years old, weighing 10–20 kg, and body condition scores 4–6/9 admitted for periodontal treatment.

Methods

Isoflurane-anesthetized dogs in dorsal recumbency were ventilated until 1 h with a volume-controlled ventilation mode using 8 mL kg−1 of VT. The dogs were distributed in 2 groups: in the ARM group, PEEP starts in 0 cmH2O, increasing gradually 5 cmH2O every 3 min, until reach 15 cmH2O and decreasing in the same steps until 5 cmH2O, maintaining this value until the end; and PEEP group, in which the pressure 5 cmH2O was instituted from the beginning of anesthesia and maintained the same level up to the end of the anesthesia. Cardiopulmonary, metabolic, oxygenation parameters, and respiratory mechanics were recorded after the anesthesia induction (baseline—BL), 15, 45, and 75 min after BL and during the recovery.

Results

The ARM increased the static compliance (Cst) (15 min after baseline) when compared with baseline moment (24.9 ± 5.8 mL cmH20−1 vs. 20.7 ± 5.4 mL cmH20−1p = 0.0364), oxygenation index (PaO2/FIO2) (505.6 ± 59.2 mmHg vs. 461.2 ± 41.0 mmHg—p = 0.0453) and reduced the shunt fraction (3.4 ± 2.4% vs. 5.5 ± 1.6%—p = 0.062). In the PEEP group, no statistical differences were observed concerning the variables evaluated. At the beginning of the evaluation, the driving pressure (DP) before ARM was significantly greater than all other evaluation time points (6.9 ± 1.8 cmH20).

Conclusions and Clinical Relevance

The use of 8 mL kg−1 of VT and 5 cmH20 PEEP without ARM maintain adequate oxygenation and mechanical ventilation in dental surgeries for up to 1 h. The use of ARM slightly improved compliance and oxygenation during the maneuver.