Cardiovascular function, pulmonary gas exchange and tissue oxygenation in isoflurane-anesthetized, mechanically ventilated Beagle dogs with four levels of positive end-expiratory pressure

Publikationen als Autor:in / Herausgeber:in der Vetmeduni

Braun, Christina

Abstrakt

Objectives To compare pulmonary gas exchange, tissue oxygenation and cardiovascular effects of four levels of end-expiratory pressure: no positive end-expiratory pressure (ZEEP), positive end-expiratory pressure (PEEP) of maximal respiratory system compliance (PEEPmaxC(rs)), PEEPmaxC(rs) + 2 cmH(2)O (PEEPmaxC(rs+2)), PEEPmaxC(rs)( )+ 4 cmH(2)O (PEEPmaxC(rs+4)), in isoflurane-anesthetized dogs. Study design Prospective randomized crossover study. Animals A total of seven healthy male Beagle dogs, aged 1 year and weighing 10.2 +/- 0.7 kg (mean +/- standard deviation). Methods The dogs were administered acepromazine and anesthesia was induced with propofol and maintained with isoflurane. Ventilation was controlled for 4 hours with ZEEP, PEEPmaxC(rs), PEEPmaxC(rs)(+2) or PEEPmaxC(rs)(+4). Cardiovascular, pulmonary gas exchange and tissue oxygenation data were evaluated at 5, 60, 120, 180 and 240 minutes of ventilation and compared using a mixed-model ANOVA followed by Bonferroni test. p < 0.05 was considered significant. Results Cardiac index (CI) and mean arterial pressure (MAP) were lower in all PEEP treatments at 5 minutes when compared with ZEEP. CI persisted lower throughout the 4 hours only in PEEPmaxC(rs)(+4) with the lowest CI at 5 minutes (2.15 +/- 0.70 versus 3.45 +/- 0.94 L minute(-1) m(-2)). At 180 and 240 minutes, MAP was lower in PEEPmaxC(rs)(+4) than in PEEPmaxC(rs), with the lowest value at 180 minutes (58 +/- 7 versus 67 +/- 7 mmHg). Oxygen delivery index (DO2I) was lower in PEEPmaxC(rs)(+4) than in ZEEP at 5, 60, 120 and 180 minutes. Venous admixture was not different among treatments. Conclusion and clinical relevance The use of PEEP caused a transient decrease in MAP and CI in lung-healthy dogs anesthetized with isoflurane, which improved after 60 minutes of ventilation in all levels of PEEP except PEEPmaxC(rs)(+4). A clinically significant improvement in arterial oxygenation and DO2I was not observed with PEEPmaxC(rs) and PEEPmaxC(rs)(+2) in comparison with ZEEP, whereas PEEPmaxC(rs)(+4) decreased DO2I.

Dokumententyp

Originalarbeit

DOI

10.1016/j.vaa.2021.01.007

PubMed ID

MEDLINE:33741264