Prediction of inspired oxygen fraction for targeted arterial oxygen tension following open heart surgery in non-smoking and smoking patients
- 132 Downloads
Simple and accurate expressions describing the PaO2–FiO2 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 PaO2–FiO2 data pairs were obtained from 25 non-smoking patients mechanically ventilated following open heart surgeries. One data pair was collected at each of FiO2 of 40, 60, 80, and 100% while maintaining same mechanical ventilation support settings. Similarly, another 100 hundred PaO2–FiO2 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 PaO2–FiO2 relationship in these patients was assessed by the regression and Bland–Altman analyses. Significant correlations were seen between the true and estimated FiO2 values in non-smoking (r2 = 0.9424; p < 0.05) and smoking (r2 = 0.9466; p < 0.05) patients. Tight biases between the true and estimated FiO2 values for non-smoking (3.1%) and smoking (4.1%) patients were observed. Also, significant correlations were seen between the true and estimated PaO2/FiO2 ratios in non-smoking (r2 = 0.9530; p < 0.05) and smoking (r2 = 0.9675; p < 0.05) patients. Tight biases between the true and estimated PaO2/FiO2 ratios for non-smoking (−18 mmHg) and smoking (−16 mmHg) patients were also observed. The new mathematical expression for the description of the PaO2–FiO2 relationship is valid and accurate in non-smoking and smoking patients who are receiving mechanical ventilation for post cardiac surgery.
KeywordsOxygen Partial pressure of oxygen PaO2/FiO2 ratio Open heart
The authors thank Dr. Rani Abou-Khouzam, Dr. Sana Chalhoub, and Dr. Hicham Bou-Fakhreddine for their help in this study.
Only departmental funds were used for this study. No external funds were obtained.
Compliance with ethical standards
Conflict of interest
All authors declare that they have no competing interests.
Human and animal participants
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
- 6.Hardman G, Al-Otaibi M. Prediction of arterial oxygen tension: validation of a novel formula. AJRCCM. 2010;182:435–6.Google Scholar
- 8.El-Khatib MF, Chatburn RL. Prediction of fraction of inspired oxygen to achieve a desired arterial partial pressure of oxygen. AJRCCM. 2012;185:685–6.Google Scholar
- 9.Hulley SB, Cummings SR, Browner WS, Grady D, Newman TB (2013) Designing clinical research: an epidemiologic approach. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013. Appendix 6C, p. 79.Google Scholar
- 12.Maxwell C, Hess D, Shefet D. Use of the arterial/alveolar oxygen tension ratio to predict the inspired oxygen concentration needed for a desired arterial oxygen tension. Respir Care. 1984;29:1135–9.Google Scholar