Assessment of the rapid shallow breathing index as a predictor of weaning of patients with prolonged mechanical ventilation

Background: About 8 of patients experience prolonged mechanical ventilation after cardiac surgery. Development of criteria for successful liberation of a patient from mechanical ventilation and extubation may be highly dependent on the clinical situation. Different criteria were used for ventilator weaning. We designed a clinical trial to determine the usefulness of rapid shallow breathing index (RSBI) as a predictor for successful weaning from mechanical ventilation. Materials and Methods: In a prospective observational study, 52 patients who had prolonged mechanical ventilation (> 72 h) after open cardiac surgery were studied. Patients had 60 - min spontaneous breathing trials and satisfied at least 5 weaning predictors and fulfilled the criteria for discontinuing mechanical ventilation. Traditional weaning criteria and RSBI were determined. According to the outcome assessment of weaning, patients were divided into failure or success groups. Results: The mean RSBI values were significantly different between the failure (103.5±21.9 breath/min/L) and success groups (80.4±15.3 breath/min/L, p=0.0001). There was no significant difference regarding the values of other prediction criteria between the two groups. Using RSBI <105 (breath/min/L) as the threshold value for predicting successful weaning, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were 92.5, 70, 92.5, 70 and 88 respectively. Conclusion: Although a small number of patients require prolonged ventilatory support after open cardiothoracic surgeries, growing experience in critical care settings and mechanical ventilation cause favorable outcomes. Ventilator weaning is more likely to be successful if RSBI is less than 105 (breath/min/L). This index is a more valuable and accurate predictor of weaning than other weaning predictors. © 2007 NRITLD, National Research Institute of Tuberculosis and Lung Disease, Iran

Frequency of reoperation due to bleeding and its related factors after adult cardiac surgeries

Background: Reoperation due to bleeding in adult cardiac surgeries is an important postoperative complication that increases mortality and morbidity. Studying the risk factors and outcomes of reoperation in these patients is imperative. Methods: The present descriptive (cross-sectional) study performed a 3-month assessment of patients that underwent elective cardiac surgeries (coronary or valve surgeries or both). The inclusion criterion was being an adult undergoing elective cardiac surgeries on cardiopulmonary bypass (coronary or valve surgeries or both), and the exclusion criteria consisted of congenital heart diseases, cardiac surgeries without cardiopulmonary bypass, emergency cardiac surgeries, aneurysm and aortic dissection surgeries, known causes of bleeding due to acquired or congenital diseases, and redo cardiac surgeries. Results: Of 740 patients studied, 55 (7.43) patients returned to the operating room due to bleeding. Of these 55 patients, 74.5 had bleeding due to surgical operations, 23.6 due to tamponade, and 1.8 due to coagulation disorders. Apropos risk factors, there was a significant relationship between the international normalized ratio (INR) and bleeding after cardiac surgeries leading to reoperation (P = 0.05). Conclusions: In this study, 7.43 of the patients returned to the operating room because of bleeding, which is an acceptable percentage according to the literature. There was a significant relationship between preoperative INR and postoperative bleeding resulting in reoperation. © 2020, Iranian Heart Association. All rights reserved