Impact of body mass index on in-hospital mortality and morbidity after coronary artery bypass grafting surgery

Obesity is a common risk factor for morbidity and mortality after cardiac surgery. However, the relationship between obesity and postoperative risk has not been fully defined. A prospective study of 1015 consecutive patients undergoing isolated coronary artery bypass grafting [CABG] was carried out. Body mass index [BMI] was used as the measure of obesity and was categorized as normal weight [BMI=20-25] and obese [BMI > 25 and < 35]. The preoperative, operative, and postoperative risk factors as well as the complication and in-hospital death rates were compared between the two groups. Of the 1015 patients, 40% had a normal weight and 49% were obese. Compared with the normal-weight group, the obese group had a significantly higher incidence of diabetes mellitus [P=0.007] and lower arterial partial pressure of oxygen [PaO2] [P=0.03]. The normal-weight patients had a higher New York Heart Association [NYHA] Functional Class [P=0.03] and were at a higher risk for emergent surgery [P=0.003] or reoperation [P=0.002]. Among the postoperative complications, respiratory complications [P=0.027] were more frequent in the obese patients. The duration of mechanical ventilation [P=0.001], the incidence of arrhythmia [P=0.011], low cardiac output syndrome [P=0.001], reintubation [P=0.001], and neurological complications [P=0.003] were significantly higher in the normal-weight patients. Obesity was associated with a lower risk of reoperation for bleeding [P=0.032]. There were no significant differences in infective complications, length of intensive care unit [ICU] stay, total length of stay in hospital, and operative mortality between the groups. In the patients undergoing isolated CABG procedures, obesity did not increase the risk of operative mortality and morbidity with the exception of respiratory complications. The normal body weight patients were at a higher risk for complications than were the obese patients. Therefore, obese patients may safely undergo CABG without previous weight reduction if due attention is paid to minimize respiratory complications

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

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. 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. 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. 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

Outcome of anesthesia and open heart surgery in pergnant patients

Cardiovascular disease is an important non-obstetric cause of maternal and fetal /neonatal morbidity and mortality during pregnancy. For a pregnant woman with cardiac disease, the potential inability of the maternal cardiovascular system to contend with normal pregnancy-induced physiologic changes may produce deleterious effects on both mother and fetus. To determine the most frequent surgical indications of maternal and fetal mortality, we studied 15 cases of severe cardiac disease in pregnant women who required cardiac surgical procedures. In this descriptive study, fifteen pregnant women who underwent cardiac surgery were studied. Maternal age ranged from 27 to 36 years, and gestational age varied from 4 to 22 weeks. Most of the patients were in New York Heart Association Classes II and III. Opioid- based anesthesia with fentanyl citrate [50 micro/kg] or sufentanil [5 micro/kg] plus low dose of thiopental were used for the induction of anesthesia. During non-pulsatile cardio-pulmonary bypass, core temperature was between 28-36 °C, average CBP time was 61.2 +/- 22 min, average aortic cross-clamp time was 34.13 +/- 14 min, and mean pump pressure was maintained between 65-80 mmHg. Ten patients had severe mitral valve disease [66.6%], three had aortic valve disease [20%], one had subvalvular aortic stenosis [6.7%], and the remaining one had left atrial myxoma [6.7%]. There were five fetal deaths [33.3%] and one maternal death [6.7%]. It seems that open heart surgery in the first trimester is very hazardous for the fetus and may lead to fetal death. If possible, surgery should be carried out in the second trimester of pregnancy. The recommendations are simply guidelines because research data and clinical experience in this area are limited