Cardiopulmonary effects of positive end-expiratory pressure in anesthetized, mechanically ventilated ponies.
Abstract: To investigate the cardiopulmonary effects of positive end-expiratory pressure (PEEP), values of 10, 20, and 30 cm of H2O, were applied to anesthetized, dorsally recumbent, ventilated ponies. After IV induction of general anesthesia, PEEP was superimposed on controlled ventilation with 100% oxygen, and changes in gas exchange and cardiac function were measured. Increasing values of PEEP in these ponies caused a linear increase in the mean (+/- SEM) functional residual capacity, from a control value (zero end-expiratory pressure) of 1.7 +/- 0.24 L to 2.2 +/- 0.31, 2.9 +/- 0.32 and 3.4 +/- 0.3 L at PEEP of 10, 20, and 30 cm of H2O, respectively (P less than 0.05). Paralleling these changes, intrapulmonary shunt fraction decreased significantly (P less than 0.05) from a control value of 12.9 +/- 0.5%, to 7.5 +/- 1.1 and 2.1 +/- 0.6%, at PEEP of 20 and 30 cm of H2O, respectively. Cardiac output was decreased by increasing values of PEEP, from control value of 11.7 +/- 1.56 L/min to 9.9 +/- 1.51, 8.8 +/- 1.33 and 5.62 +/- 0.56 L/min at PEEP of 10, 20, and 30 cm of H2O, respectively. Related to decreasing cardiac output, tissue oxygen delivery also decreased as PEEP was increased, from control value of 2.0 +/- 0.09 L/min to 1.8 +/- 0.07, 1.6 +/- 0.06, and 1.03 +/- 0.04 L/min at PEEP of 10, 20, and 30 cm of H2O, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1990-05-01 PubMed ID: 2186677
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research aimed to examine how positive end-expiratory pressure (PEEP) at different levels affects the cardiopulmonary function of anesthetized, mechanically ventilated ponies. It was found that as PEEP levels increased, both cardiac output and tissue oxygen delivery decreased, but there was a linear increase in functional residual capacity.
Research Methodology and Experiment
- The research team investigated the effects of PEEP on anesthetized ponies in a dorsal recumbent position.
- After inducing general anesthesia intravenously, the researchers supplemented controlled ventilation with 100% oxygen and introduced PEEP.
- Three PEEP levels were used for the study: 10, 20, and 30 centimeters of H2O.
- The team measured the changes in gas exchange and cardiac function that resulted from the different PEEP levels.
Effects of PEEP on Functional Residual Capacity
- The functional residual capacity increased linearly with ascending PEEP levels
- Without PEEP (the control group), the functional residual capacity was 1.7 +/- 0.24 L.
- At PEEP levels of 10, 20, and 30 cm of H2O, the functional residual capacities increased to 2.2, 2.9, and 3.4 L, respectively.
Effects of PEEP on Intrapulmonary Shunt Fraction
- PEEP also had a significant effect on the intrapulmonary shunt fraction, which decreased as the PEEP levels increased.
- The intrapulmonary shunt fraction decreased from a control value of 12.9%, to 7.5% at a PEEP level of 20 cm of H2O, and 2.1% at a PEEP level of 30 cm of H2O.
Effects of PEEP on Cardiac Output and Tissue Oxygen Delivery
- In contrast, cardiac output and tissue oxygen delivery decreased as PEEP levels rose.
- Without any PEEP (control), the cardiac output was 11.7 L/min, which fell to 9.9, 8.8, and 5.62 L/min at PEEP levels of 10, 20, and 30 cm H2O respectively.
- Tissue oxygen delivery also decreased from 2.0 L/min to 1.8, 1.6, and 1.03 L/min at PEEP levels of 10, 20, and 30 cm of H2O respectively.
Conclusions
- The research indicates that while PEEP enhances the functional residual capacity and reduces the intrapulmonary shunt fraction, it negatively impacts cardiac output and oxygen delivery to tissues.
- These findings are essential to understand the comprehensive effects of positive end-expiratory pressure in the realm of veterinary anesthesia and pulmonary care.
Cite This Article
APA
Wilson DV, Soma LR.
(1990).
Cardiopulmonary effects of positive end-expiratory pressure in anesthetized, mechanically ventilated ponies.
Am J Vet Res, 51(5), 734-739.
Publication
Researcher Affiliations
- Department of Clinical Studies, University of Pennsylvania, School of Veterinary Medicine, New Bolten Center, Kennett Square 19348.
MeSH Terms
- Anesthesia / veterinary
- Animals
- Blood Gas Monitoring, Transcutaneous / veterinary
- Cardiac Output
- Guaifenesin
- Horses / physiology
- Hypoxia / therapy
- Methohexital
- Positive-Pressure Respiration / veterinary
- Respiratory Function Tests
Citations
This article has been cited 6 times.- Bukoski A, Downs J, Hodgson DS, Le-Bert CR, Thomen R, Flors L, Thombs L, Bailey J. Cardiopulmonary effects of apneustic anesthesia ventilation in anesthetized pigs: a new mode of ventilation for anesthetized veterinary species. Front Vet Sci 2024;11:1378617.
- Brandly JE, Midon M, Douglas HF, Hopster K. Flow-controlled expiration reduces positive end-expiratory pressure requirement in dorsally recumbent, anesthetized horses. Front Vet Sci 2023;10:1135452.
- Leung J, Beths T, Lynch M, Frith S, Bauquier SH. A simple method to provide positive end expiratory pressure to treat hypoxaemia in an anaesthetised Asian Elephant (Elephas maximus). J S Afr Vet Assoc 2021 May 19;92(0):e1-e4.
- Karrasch NM, Hubbell JA, Aarnes TK, Bednarski RM, Lerche P. Comparison of cardiorespiratory variables in dorsally recumbent horses anesthetized with guaifenesin-ketamine-xylazine spontaneously breathing 50% or maximal oxygen concentrations. Can Vet J 2015 Apr;56(4):387-92.
- Gregson R, Clutton RE. Near-fatal misuse of medical tape around an endotracheal tube connector during inhalation anesthesia in a horse. Can Vet J 2012 Sep;53(9):978-82.
- Hubbell JA, Aarnes TK, Bednarski RM, Lerche P, Muir WW. Effect of 50% and maximal inspired oxygen concentrations on respiratory variables in isoflurane-anesthetized horses. BMC Vet Res 2011 Jun 3;7:23.
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