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One‐Lung Versus Two‐Lung Ventilation in the Closed‐Chest Anesthetized Dog: A Comparison of Cardiopulmonary Parameters
Author(s) -
Cantwell Shauna L.,
Duke Tanya,
Walsh Peter J.,
Remedios Audrey M.,
Walker David,
Ferguson James G.
Publication year - 2000
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1053/jvet.2000.7545
Subject(s) - medicine , anesthesia , pulmonary shunt , tidal volume , ventilation (architecture) , acepromazine , arterial blood , heart rate , blood pressure , respiratory system , hemodynamics , mechanical engineering , engineering
Objective— To evaluate cardiopulmonary effects of one‐lung ventilation (OLV) versus two‐lung ventilation (TLV) in closed‐chest anesthetized dogs. Study Design— Controlled, randomized experiment. Animals— Fourteen, 2‐ to 7‐year‐old adult dogs, weighing 23 ± 6 kg. Methods— The dogs were anesthetized with acepromazine, morphine, thiopental, and halothane in oxygen, ventilated, and paralyzed with vecuronium. Tidal volume was 10 mL/kg. Respiratory rate was set to maintain end‐tidal CO 2 (ETCO 2 ) at 40 ± 2 mm Hg before instrumentation then not changed. The left bronchus of 7 dogs was obstructed with a Univent bronchial blocker (Fuji Systems Corp, Tokyo, Japan). Blood gas analysis and hemodynamic measurements were taken at predetermined intervals for 1 hour in the TLV group and at baseline and following bronchial obstruction in the OLV group. Results— Shunt fraction was not significantly different between groups, but in OLV shunt increased from baseline at 5 minutes. Arterial oxygen (Pao 2 ) decreased after baseline in OLV compared with TLV. Arterial carbon dioxide (Paco 2 ) increased with OLV and decreased with TLV. In OLV, systemic vascular resistance was variable and decreased compared with TLV. Cardiac index increased over time in both groups but was not affected by treatment. Heart rate, mean arterial pressure, and diastolic arterial pressure increased with OLV compared with TLV but did not change over time. Conclusion— This study shows that OLV statistically decreases oxygen tension and transiently increases shunt fraction, but with 100% O 2 it appears to be a feasible procedure with minimal cardiopulmonary side effects in healthy dogs. Clinical Relevance— OLV is a feasible procedure in anesthetized dogs to better facilitate thoracic procedures such as bronchopleural fistula repair and thoracoscopy.