The effects of oxygen induced pulmonary vasoconstriction on bedside measurement of pulmonary gas exchange.
Ulla Møller WeinreichLars P ThomsenStephen E ReesBodil S RasmussenPublished in: Journal of clinical monitoring and computing (2015)
In patients with respiratory failure measurements of pulmonary gas exchange are of importance. The bedside automatic lung parameter estimator (ALPE) of pulmonary gas exchange is based on changes in inspired oxygen (FiO2) assuming that these changes do not affect pulmonary circulation. This assumption is investigated in this study. Forty-two out of 65 patients undergoing coronary artery bypass grafting (CABG) had measurements of mean pulmonary arterial pressure (MPAP), cardiac output and pulmonary capillary wedge pressure thus enabling the calculation of pulmonary vascular resistance (PVR) at each FiO2 level. The research version of ALPE was used and FiO2 was step-wise reduced a median of 0.20 and ultimately returned towards baseline values, allowing 6-8 min' steady state period at each of 4-6 levels before recording the oxygen saturation (SpO2). FiO2 reduction led to median decrease in SpO2 from 99 to 92 %, an increase in MPAP of 4 mmHg and an increase in PVR of 36 dyn s cm(-5). Changes were immediately reversed on returning FiO2 towards baseline. In this study changes in MPAP and PVR are small and immediately reversible consistent with small changes in pulmonary gas exchange. This indicates that mild deoxygenation induced pulmonary vasoconstriction does not have significant influences on the ALPE parameters in patients after CABG.
Keyphrases
- pulmonary hypertension
- coronary artery bypass grafting
- patients undergoing
- end stage renal disease
- chronic kidney disease
- heart failure
- machine learning
- respiratory failure
- acute coronary syndrome
- percutaneous coronary intervention
- drug induced
- ejection fraction
- peritoneal dialysis
- prognostic factors
- ionic liquid
- single molecule