Myocardial ischaemia after coronary artery bypass grafting: early vs late extubation.

The technique of early extubation after coronary artery bypass grafting is increasing in popularity, but its safety and effect on myocardial ischaemia remain to be established. In a randomized, prospective study, patients undergoing routine elective coronary artery bypass grafting were managed with either early or late tracheal extubation. The incidence and severity of electrocardiographic myocardial ischaemia were compared. Data were analysed from 85 patients (43 early extubation; 42 late extubation). Median time to extubation was 110 min in the early extubation patients and 757 min in the late extubation patients. After correction for randomization bias, there were no significant differences between groups in ischaemic burden, maximal ST-segment deviation, incidence of ischaemia and area under the ST deviation-time curve (integral of ST deviation and time). Similarly, there were no differences between groups in postoperative creatine kinase MB-isoenzyme concentrations and duration of stay in the ICU or hospital. Therefore, this study provides evidence for the safety of early extubation after routine coronary artery bypass grafting.

Gastroesophageal reflux and tracheobronchial contamination after cardiac surgery: should a nasogastric tube be routine?

Nasogastric (NG) tubes are routinely used in patients undergoing cardiac surgery. This randomized study was designed to assess gastroesophageal reflux (GER) without a NG tube (control) compared with a NG tube managed either by gravity drainage (gravity) or continuous low-grade suction (suction). Antimony pH probes were placed in the lower esophagus and trachea after induction of anesthesia in 51 patients, and pH was recorded every 5 s until the time of tracheal extubation. GER was defined as reversible decrease in esophageal pH to less than 4.0. No significant difference was found between groups in age, weight, gender, duration of postoperative ventilation, morphine use, or antiemetic use. All indicators of GER were seen more frequently in the gravity group compared with the two other groups (P < 0.001). One episode of sudden decrease in tracheal pH was observed in a patient in the gravity group, indicating tracheal aspiration, which was associated with delayed extubation and postoperative pneumonia. The absence of a NG tube is not associated with reflux, probably since the gastroesophageal sphincter remains competent. NG tubes are not routinely necessary for cardiac surgery in patients without risk factors for GER, and increase reflux risk if managed without low-grade suction.