Lung aeration and volumes following alveolar recruitment maneuvers with three airway pressures in healthy anesthetized and mechanically ventilated Beagle dogs

Joaquin Araos; Samantha Sedgwick; Francesco Staffieri; Pablo Donati; Manuel Martin-Flores

doi:10.1016/j.vaa.2022.06.005

Lung aeration and volumes following alveolar recruitment maneuvers with three airway pressures in healthy anesthetized and mechanically ventilated Beagle dogs

Vet Anaesth Analg. 2022 Sep;49(5):443-451. doi: 10.1016/j.vaa.2022.06.005. Epub 2022 Jul 1.

Authors

Joaquin Araos¹, Samantha Sedgwick², Francesco Staffieri³, Pablo Donati⁴, Manuel Martin-Flores⁵

Affiliations

¹ Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA. Electronic address: jda246@cornell.edu.
² Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA; Columbia Veterinary Emergency Trauma and Specialty (CVETS), Columbia, SC, USA.
³ Department of Emergency and Organ Transplantation, Section of Veterinary Clinics and Animal Production, University of Bari, Bari, Italy.
⁴ Department of Anesthesiology and Pain Management, Faculty of Veterinary Sciences, Universidad de Buenos Aires, Buenos Aires, Argentina.
⁵ Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.

PMID: 35918277
DOI: 10.1016/j.vaa.2022.06.005

Abstract

Objective: To compare the effects of three recruitment airway pressures (RP_aw) on lung aeration and volumes in mechanically ventilated dogs during propofol anesthesia.

Study design: Prospective, crossover randomized experimental study.

Animals: A total of eight healthy anesthetized experimental Beagle dogs in dorsal recumbency.

Methods: Dogs were mechanically ventilated with a tidal volume of 15 mL kg^-1 and zero positive end-expiratory pressure and 100% oxygen. Three maneuvers consisting of a 30 second inspiration at RP_aws of 15 (RP_aw15), 25 (RP_aw25) and 35 (RP_aw35) cmH₂O were performed randomly, 15 minutes apart. Changes in lung aeration and lung deformation were compared with end-expiratory baseline (before the application of each RP_aw) and between-RP_aws using computed tomography scans and calculations of global lung strain. Between-group comparisons were performed with one-way anova for repeated measures followed by Tukey test for multiple comparisons. A p value < 0.05 was considered significant.

Results: The amount of nonaeration was minimal (<1%) at baseline and not different with the application of the RP_aws. The amount of hypoaeration and normoaeration during baseline decreased with all RP_aws (p < 0.001). There was no difference between RP_aws regarding hypoaeration (all p > 0.999), whereas normoaeration was higher at RP_aw15 than RP_aw25 and RP_aw35 (p < 0.009). Compared with baseline, the fraction of hyperaerated alveoli increased with each RP_aw (p < 0.001) and was lower during RP_aw15 than RP_aw25 and RP_aw35 (both p ≤ 0.007). Global lung strain was lower during RP_aw15 than at higher RP_aw (p < 0.001).

Conclusions and clinical relevance: A RP_aw of 15 cmH₂O for 30 seconds was the recommended RP_aw because it was as effective at reversing hypoaeration as RP_aws of 25 and 35 cmH₂O but with less hyperaeration and potential for overdistension of the lungs in this particular population of dogs with negligible atelectasis.

Keywords: alveolar recruitment maneuver; anesthesia; dogs; lung aeration; mechanical ventilation.

Publication types

Clinical Trial, Veterinary

MeSH terms

Animals
Dogs
Lung
Oxygen
Propofol* / pharmacology
Prospective Studies
Respiration, Artificial* / methods
Respiration, Artificial* / veterinary
Tidal Volume

Substances

Oxygen
Propofol