Utility of intra-operative capnogram to detect branch pulmonary artery obstruction following total correction of tetralogy of fallot.

Branch pulmonary artery obstruction is one of the prime reasons for re-operation in patients who have undergone repair for tetralogy of Fallot. Branch pulmonary artery obstruction may develop over a period of time due to dilation of right ventricular outflow tract or it may be caused by residual stenosis after inadequate repair. This may lead to differential lung perfusion causing morbidity. Intra-operative capnogram monitoring reveals ventilation−perfusion relationship. We report two cases where the capnogram helped the diagnosis and management of branch pulmonary artery obstruction. We found a redundant patch in the first and an extra length of the homograft in second case which led to the obstruction. However, but for the changes in the intraoperative capnogram, this condition may by far remain undiagnosed considering the fact that it does not produce hemodynamic changes but can lead to postoperative morbidity.

Intra-operative trans-esophageal echocardiography in congenital heart disease.

Intra-operative trans-esophageal echocardiography (TEE) is an important monitoring and diagnostic tool used during surgery for repair of congenital heart disease. In several studies,TEE has been shown to provide additional intra-cardiac anatomic information. Its ability to be used intra- operatively before and after cardiac repair makes it a unique tool. Before TEE was available for intra-operative use, significant residual abnormalities were frequently not detected. The result was often substantial post-operative morbidity and mortality and sometimes the need for re-operation. According to practice guidelines established by the Society of Cardiovascular Anesthesiologists and the American Society of Anesthesiologists, there is strong evidence for the usefulness of TEE in surgery for congenital heart disease because it significantly improves the clinical outcome of these patients. Before surgical correction, TEE helps confirm diagnosis and spot any additional lesion, while after the surgical correction, it provides baseline parameters for comparison after the surgical correction.

Ultra low dose aprotinin decreases blood loss and transfusion requirements in high risk two valve replacement surgery.

The efficacy of ultra-low-dose-aprotinin (ULDA) in 'high-risk' two valve replacement surgery, was evaluated in this prospective, randomized, double-blind study. Forty adult high-risk patients undergoing elective two valve replacement surgery, were included. The patients were divided into 2 groups of 20 each. In Group I, aprotinin in a dose of 1,000,000 KIU was administered from the end of anaesthesia induction to the time of sternotomy after a 1 ml of test dose. In Group II (control), 100 ml of normal saline was administered in a similar fashion. Coagulation parameters, blood loss, and amount of transfusion of blood / blood products were measured at specific intervals. The postoperative chest tube drainage in the first 24 hours was significantly less 203+/-35 ml (p<0.05) in Group I as compared with 490+/-104 ml in group II and consequently, Group I patients received significantly less (p<0.05) red cell concentrates and platelet transfusion. There was a significant decrease in the length of postoperative elective ventilation, intensive care unit (ICU) stay and direct costs involved in the hospital expenses with the use of ULDA. We conclude that ULDA is safe and effective in 'high-risk' two-valve replacement surgery to reduce postoperative bleeding, postoperative length of intubation and ICU stay; use of ULDA is associated with significant direct cost savings.

Influence of isoflurane on ischaemic heart disease in patients with coronary steal prone anatomy.

It is postulated that patients with ischaemic heart disease (IHD) and coronary steal prone anatomy (CSPA) may develop myocardial ischaemia under isoflurane anaesthesia. This study was conducted in 50 patients undergoing coronary artery bypass grafting. Among these 10 patients (20%) had CSPA, as evidenced by coronary angiography. Anaesthesia was induced with fentanyl, midazolam and thiopentone and maintained with isoflurane in oxygen after endotracheal intubation. Patients were continuously monitored with automated ST segment analysis of electrocardiogram (ECG) and transoesophageal echocardiography (TEE). The end-tidal concentration of isoflurane was maintained at 1.2%, which is equal to one minimum alveolar concentration. Haemodynamic parameters were maintained within 20% of baseline values with either the use of phenylephrine or increasing the depth of anaesthesia by using midazolam and fentanyl. ST changes were measured after 80 ms of J-point in ECG and TEE monitored for occurrence of new regional wall motion abnormalities during the study period. ST changes more than +/-1.0 mm were considered as an indication of myocardial ischaemia. Out of 10 patients having CSPA, 50% developed significant ECG changes during isoflurane anaesthesia at an endtidal concentration of 1.2%. In patients not having CSPA new ischaemia was not observed. Our study indicates necessity of close monitoring of patients with IHD and CSPA during isoflurane anaesthesia to identify new ischaemia and institute appropriate measures.