Prediction of inspired oxygen fraction for targeted arterial oxygen tension following open heart surgery in non-smoking and smoking patients

Abstract

Simple and accurate expressions describing the PO-FO relationship in mechanically ventilated patients are lacking. The current study aims to validate a novel mathematical expression for accurate prediction of the fraction of inspired oxygen that will result in a targeted arterial oxygen tension in non-smoking and smoking patients receiving mechanical ventilation following open heart surgeries. One hundred PO-FO data pairs were obtained from 25 non-smoking patients mechanically ventilated following open heart surgeries. One data pair was collected at each of FO of 40, 60, 80, and 100% while maintaining same mechanical ventilation support settings. Similarly, another 100 hundred PO-FO data pairs were obtained from 25 smoking patients mechanically ventilated following open heart surgeries. The utility of the new mathematical expression in accurately describing the PO-FO relationship in these patients was assessed by the regression and Bland-Altman analyses. Significant correlations were seen between the true and estimated FO values in non-smoking (r = 0.9424; p < 0.05) and smoking (r = 0.9466; p < 0.05) patients. Tight biases between the true and estimated FO values for non-smoking (3.1%) and smoking (4.1%) patients were observed. Also, significant correlations were seen between the true and estimated PO/FO ratios in non-smoking (r = 0.9530; p < 0.05) and smoking (r = 0.9675; p < 0.05) patients. Tight biases between the true and estimated PO/FO ratios for non-smoking (-18 mmHg) and smoking (-16 mmHg) patients were also observed. The new mathematical expression for the description of the PO-FO relationship is valid and accurate in non-smoking and smoking patients who are receiving mechanical ventilation for post cardiac surgery.

Comparing supervised machine learning algorithms for the prediction of partial arterial pressure of oxygen during craniotomy

“…To overcome this limitation, several approaches have been developed aiming at a non-invasive and continuous estimation of the partial oxygen pressure (paO 2 ) as a proxy for blood oxygenation [11][12][13][14][15][16][17]. These methods estimate blood oxygenation from the fraction of inspired oxygen (FiO 2 ) and oxygen saturation (SpO 2 ) [8][9][10], from the oxygen transfer slope and estimated membrane oxygen transfer [11], via the alveolar gas equation [12], and from venous blood gas samples [13][14][15][16]. However, we will show that none of these methods are particularly precise and that they also face other limitations such as upper or lower limits of utilized formulas.…”