Ventilation distribution assessed with electrical impedance tomography and the influence of tidal volume, recruitment and positive end-expiratory pressure in isoflurane-anesthetized dogs.

Autor: Ambrosio AM; Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil; Laboratory of Medical Investigation 8, Posgraduate Program in Anesthesiology, Medical School, University of São Paulo, São Paulo, Brazil., Carvalho-Kamakura TPA; Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Ida KK; Laboratory of Medical Investigation 8, Posgraduate Program in Anesthesiology, Medical School, University of São Paulo, São Paulo, Brazil. Electronic address: keila.ida@ulg.ac.be., Varela B; Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Andrade FSRM; Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Facó LL; Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Fantoni DT; Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil; Laboratory of Medical Investigation 8, Posgraduate Program in Anesthesiology, Medical School, University of São Paulo, São Paulo, Brazil.
Jazyk: angličtina
Zdroj: Veterinary anaesthesia and analgesia [Vet Anaesth Analg] 2017 Mar; Vol. 44 (2), pp. 254-263. Date of Electronic Publication: 2017 Jan 11.
DOI: 10.1016/j.vaa.2016.06.003
Abstrakt: Objective: To examine the intrapulmonary gas distribution of low and high tidal volumes (V T ) and to investigate whether this is altered by an alveolar recruitment maneuver (ARM) and 5 cmH 2 O positive end-expiratory pressure (PEEP) during anesthesia.
Study Design: Prospective randomized clinical study.
Animals: Fourteen client-owned bitches weighing 26 ± 7 kg undergoing elective ovariohysterectomy.
Methods: Isoflurane-anesthetized dogs in dorsal recumbency were ventilated with 0 cmH 2 O PEEP and pressure-controlled ventilation by adjusting the peak inspiratory pressure (PIP) to achieve a low (7 mL kg -1 ; n = 7) or a high (12 mL kg -1 ; n = 7) V T . Ninety minutes after induction (T90), an ARM (PIP 20 cmH 2 O for 10 seconds, twice with a 10 second interval) was performed followed by the application of 5 cmH 2 O PEEP for 35 minutes (RM35). The vertical (ventral=0%; dorsal=100%) and horizontal (right=0%; left=100%) center of ventilation (CoV), four regions of interest (ROI) (ventral, central-ventral, central-dorsal, dorsal) identified in electrical impedance tomography images, and cardiopulmonary data were analyzed using two-way repeated measures anova.
Results: The low V T was centered in more ventral (nondependent) areas compared with high V T at T90 (CoV: 38.8 ± 2.5% versus 44.6 ± 7.2%; p = 0.0325). The ARM and PEEP shifted the CoV towards dorsal (dependent) areas only during high V T (50.5 ± 7.9% versus 41.1 ± 2.8% during low V T , p = 0.0108), which was more distributed to the central-dorsal ROI compared with low V T (p = 0.0046). The horizontal CoV was centrally distributed and cardiovascular variables remained unchanged throughout regardless of the V T , ARM, and PEEP.
Conclusions and Clinical Relevance: Both low and high V T were poorly distributed to dorsal dependent regions, where ventilation was improved following the current ARM and PEEP only during high V T . Studies on the role of high V T on pulmonary complications are required.
(Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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