Optimizing the Yield of Abnormal Preoperative Chest Radiographs in Elective Non-cardiothoracic Surgery: Development of a Risk Prediction Score and External Validation.

BACKGROUND: Guideline recommendations for preoperative chest radiographs vary to the extent that individual patient benefit is unclear. We developed and validated a prediction score for abnormal preoperative chest radiographs in adult patients undergoing elective non-cardiothoracic surgery. METHODS: Our prospective observational study recruited 703 adult patients who underwent elective non-cardiothoracic surgery at Ramathibodi Hospital. We developed a risk prediction score for abnormal preoperative chest radiographs with external validation using data from 411 patients recruited from Thammasat University Hospital. The discriminative performance was assessed by receiver operating curve analysis. In addition, we assessed the contribution of abnormal chest radiographs to perioperative management. RESULTS: Abnormal preoperative chest radiographs were found in 19.5% of the 703 patients. Age, pulmonary disease, cardiac disease, and diabetes were significant factors. The model showed good performance with a C-statistics of 0.739 (95% CI, 0.691-0.786). We classified patients into four groups based on risk scores. The posttest probabilities in the intermediate-, intermediate-high-, and high-risk groups were 33.2%, 59.8%, and 75.7%, respectively. The model fitted well with the external validation data with a C statistic of 0.731 (95% CI, 0.674-0.789). One (0.4%) abnormal chest radiograph from the low-risk group and three (2.4%) abnormal chest radiographs from the intermediate-to-high-risk group had a major impact on perioperative management. CONCLUSIONS: Four predictors including age, pulmonary disease, cardiac disease, and diabetes were associated with abnormal preoperative chest radiographs. Our risk score demonstrated good performance and may help identify patients at higher risk of chest abnormalities.

Postoperative Supplemental Oxygen Is Unnecessary in Low-Risk Cesarean Delivery Parturients Under Spinal Anesthesia: An Observational Study.

The incidence of maternal oxygen desaturation after cesarean delivery in the postanesthesia care unit (PACU) has not been thoroughly reported. The purpose of this study was to evaluate the incidence of desaturation and to describe the frequency of supplemental oxygen administration in patients being monitored in the PACU. This study was conducted in a tertiary care hospital, and low-risk parturients undergoing cesarean delivery under spinal anesthesia were enrolled. None of the subjects received supplemental oxygen therapy on arrival at the PACU. Their oxygen saturation was continuously monitored using pulse oximetry. Desaturation was defined as an oxygen saturation at or below 94% for more than 30 seconds. The data of 324 healthy, term parturients were included in the analysis. The incidence of desaturation was only 0.3% (95% confidence interval = 0.01%-1.7%). No patient required supplemental oxygen therapy in the PACU. The incidence of postoperative oxygen desaturation in healthy parturients undergoing elective cesarean delivery under spinal anesthesia was uncommon. Routine administration of supplemental oxygen in the PACU is therefore unnecessary.