ABSTRACT
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.
ABSTRACT
BACKGROUND: The modified Mallampati classification (MMC) provides an estimate of the tongue size relative to the oral cavity size, and is a usual screening tool for predicting difficult laryngoscopy. Previous studies have indicated an increase of MMC during the progression of pregnancy, but there is no comprehensive study in pregnant women undergoing cesarean delivery. The primary aim of this study was to evaluate the MMC before and after cesarean delivery. METHODS: This is a prospective observational study of 104 women who underwent cesarean section. MMC, thyromental distance, neck circumference, and upper lip bite test were evaluated at 4 different time points: during the pre-anesthetic visit (T0) and at 1 (T1), 6 (T2), and 24 (T3) hours after delivery. Factors evaluated for their predictive validity included gestational weight gain, operation time, amount of intravascular fluids, oxytocin dosage, and blood loss. The correlation between each factor and the MMC classification was tested by logistic regression. RESULTS: From 104 participants, 59.6% experienced Mallampati class changes. The proportions of patients classified as Mallampati III and IV at different time points were: T0 = 48.1% (MMC III only), T1 = 75.0%, T2 = 80.8%, and T3 = 84.6%, respectively. Gestational weight gain, duration of surgery, anesthetic method, blood loss, oxytocin dosage, or amount of intravenous fl uid were not correlated with the MMC change. CONCLUSION: The number of patients with initial Mallampati III was high. In addition, a significant increase in MMC occurred after cesarean delivery. The data confirm the particular risk status of women undergoing cesarean delivery particularly regarding airway anatomy.
