Entropy score, patent ductus arteriosus (PDA), and cardiopulmonary bypass (CPB): Ligation of PDA on CPB can compromise cerebral blood flow.

A patent ductus arteriosus (PDA) is often present in patients undergoing correction of congenital heart disease. It is well appreciated that during cardiopulmonary bypass (CPB), a PDA steals arterial inflow into pulmonary circulation, and may lead to systemic hypoperfusion, excessive pulmonary blood flow (PBF) and distention of the left heart. Therefore, PDA is preferably ligated before initiation of CPB. We describe acute decreases of arterial blood pressure and entropy score with the initiation of CPB and immediate increase in entropy score following the PDA ligation in a child undergoing intracardiac repair of ventricular septal defect and right ventricular infundibular stenosis. The observation strongly indicates that a PDA steals arterial inflow into pulmonary circulation and if the PDA is dissected and ligated on CPB or its ligation on CPB is delayed the cerebral perfusion is potentially compromised.

Pericardial tamponade after left posterolateral thoracotomy for left upper lobectomy for pulmonary aspergilloma.

Pericardial tamponade limits diastolic filling of the heart; therefore, a high venous pressure is required to fill the ventricle. In presence of cardiac tamponade, therapeutic agents and manoeuvres that results in venodilation or vasodilation can severely compromise diastolic filling of the heart and might result in rapid cardiac decompensation. Equalization of central venous pressure and pulmonary artery diastolic pressure or equalization of pressures in all four chambers during diastole confirms cardiac tamponade. Transthoracic echocardiography can detect the site of tamponade and assist in pericardiocentesis. We describe acute pericardial tamponade in a young man who underwent left posterolateral thoracotomy for left upper lobectomy. Intraoperatively, mobilization of the left upper lobe was frequently associated with hypotension. Postoperatively, the patient suffered two more episodes of hypotension. The episodes of hypotension were attributed to surgical manipulation and epidural blockade. Hemodynamics normalized after discontinuing epidural infusion, volume resuscitation and lobectomy. On third postoperative day, the patient developed cardiovascular collapse; arterial blood pressure and central venous pressure were 70/50 and 12 mmHg. Investigations showed haziness of left lung, and severe respiratory acidosis. On opening of the left thoracotomy wound, pericardial tamponade was diagnosed. A pericardial window was created and tamponade was released with that the hemodynamics normalized. Episodes of unexplained hypotension after left upper lobectomy suggest a cardiac etiology and acute pericardial tamponade is a possibility which should be released immediately otherwise it can result in fatal outcome.

Infrarenal abdominal aortic aneurysm repair in presence of coronary artery disease: Optimization of myocardial stress by controlled phlebotomy.

The repair of abdominal aortic aneurysm (AAA) in the presence of significant coronary artery disease (CAD) carries a high-risk of adverse peri-operative cardiac event. The options to reduce cardiac risk include perioperative β-blockade, preoperative optimization by myocardial revascularization and simultaneous (combined) coronary artery bypass grafting and aneurysm repair. We describe intra-operative controlled phlebotomy to optimize myocardial stress during repair of infrarenal AAA in a patient with significant stable CAD.

Superior vena cava syndrome after pulsatile bidirectional Glenn shunt procedure: perioperative implications.

Bidirectional superior cavopulmonary shunt (bidirectional Glenn shunt) is generally performed in many congenital cardiac anomalies where complete two ventricle circulations cannot be easily achieved. The advantages of BDG shunt are achieved by partially separating the pulmonary and systemic venous circuits, and include reduced ventricular preload and long-term preservation of myocardium. The benefits of additional pulsatile pulmonary blood flow include the potential growth of pulmonary arteries, possible improvement in arterial oxygen saturation, and possible prevention of development of pulmonary arteriovenous malformations. However, increase in the systemic venous pressure after BDG with additional pulsatile blood flow is known. We describe the peri-operative implications of severe flow reversal in the superior vena cava after pulsatile BDG shunt construction in a child who presented for surgical interruption of the main pulmonary artery.

Perioperative issues due to long-standing lung collapse during repair of a large ascending aortic aneurysm.

Acute lung collapse during open-heart surgery may potentially lead to problems such as inadequate gas exchange, increased pulmonary vascular resistance, increased afterload to the right ventricle, and difficulty in weaning from cardiopulmonary bypass (CPB). Therefore, expansion of the lungs is ensured prior to separation from CPB. We report the inability to manually expand a chronically collapsed lung during the repair of ascending aortic aneurysm. The collapsed lung did not pose difficulty in separation from CPB and in blood gas management during the perioperative period. We discuss perioperative management issues in such situations.

Anesthesia for awake craniotomy: A retrospective study.

Context: Awake craniotomy is increasingly performed the world over. We share our experience of performing craniotomy awake with our anesthetic protocol. Aims: To evaluate and analyze the anesthesia records of the patients who underwent awake craniotomy at our institution. Settings and Design: University teaching hospital, Retrospective study. Materials and Methods: We reviewed records of the 42 consecutive patients who underwent awake craniotomy under conscious sedation using Fentanyl and Propofol infusion until December 2005. The drugs were titrated (Bispectral monitoring was used in 16 patients) to facilitate intermittent intraoperative neurological testing. All patients received scalp blocks with a mixture of bupivacaine and lignocaine with adrenaline. Haloperidol and ondansetron were administered in all patients at induction of anesthesia. Results: All patients completed the procedure. One patient each needed endotracheal intubation and LMA for airway control during closure, while another required CPAP perioperatively because of desaturation to < 80%. There was significantly decreased use of anesthetics (P < 0.001) and a trend towards reduction in complications (e.g. respiratory depression and deep sedation) (P> 0.05) with the use of BIS as compared to without BIS. Intraoperative complications were hypertension (19%), tight brain (14.2%), focal seizure (9.5%) respiratory depression (7.1%), deep sedation (7.1%), tachycardia (7.1%) and bradycardia. Two patients desaturated to < 95%. 23.8% patients developed transient neurological deficits. The most frequent postoperative complications were PONV (19%) and seizures (16.6%). Conclusions: With the use of advanced monitoring and newer anesthetics, awake craniotomy is a relatively safe procedure with an accepted rate of complications.

Anesthesia and intracranial arteriovenous malformation.

Anesthetic management of intracranial arteriovenous malformation (AVM) poses multiple challenges to the anesthesiologist in view of its complex and poorly understood pathophysiology and multiple modalities for its treatment involving different sub-specialties. The diagnosis of AVM is based on clinical presentation as well as radiological investigation. Pregnant patients with intracranial AVM and neonates with vein of Galen malformation may also pose a special challenge and require close attention. Despite technological advancement, reported morbidity or mortality after AVM treatment remains high and largely depends on age of the patient, recruitment of perforating vessels, its size, location in the brain, history of previous bleed and post-treatment hyperemic complication. Anesthetic management includes a thorough preoperative visit with meticulous planning based on different modalities of treatment including anesthesia for radiological investigation. Proper attention should be directed while transporting the patient for the procedure. Protection of the airway, adequate monitoring, and maintaining neurological and cardiovascular stability, and the patient's immobility during the radiological procedures, appreciation and management of various complications that can occur during and after the procedure and meticulous ICU management is essential.