Perioperative management of a patient with Dandy Walker malformation with tetralogy of Fallot undergoing total correction and fresh homologous pericardial pulmonary valve conduit implantation: Report of a rare case.

Perioperative management of a patient with Dandy–Walker malformation (DWM) with tetralogy of Fallot (TOF), patent ductus arteriosus, and pulmonary artery stenosis is a great challenge to the anesthesiologist. Anesthetic management in such patients can trigger tet spells that might rapidly increase intracranial pressure (ICP), conning and even death. The increase in ICP can precipitate tet spells and further brain hypoxia. To avoid an increase in ICP during TOF corrective surgery ventriculo‑peritoneal (VP) shunt should be performed before cardiac surgery. We present the first case report of a 11‑month‑old male baby afflicted with DWM and TOF who underwent successful TOF total corrective surgery and fresh autologous pericardial pulmonary valve conduit implantation under cardiopulmonary bypass after 1 week of VP shunt insertion.

Pharmacologic support of circulation in patients undergoing cardiac surgery.

Maintenance of adequate oxygen balance to all tissues is one of the primary objectives when dealing with patients undergoing cardiac surgery. Cardiac output is one of the major components of oxygen delivery so that its maintenance is an important consideration. Due to pre-operative cardiac lesion and myocardial dysfunction secondary to the events related to cardiac surgery and cardiopulmonary by-pass, circulatory support by pharmacological or mechanical means is frequently required after surgery. Therefore, inotropes and vasodilators are used to improve the myocardial performance after cardiac surgery. Epinephrine, dopamine and dobutamine are commonly used inotropes. Dopexamine and phosphodiesterase inhibitors such as amrinone, milrinone and enoximone are some of the newer agents that have been introduced in clinical practice. Amongst the vasodilators, sodium nitroprusside and nitroglycerin are commonly used. Alpha adrenergic blockers such as phentolamine and phenoxybenzamine and calcium channel blockers such as diltiazem are some other vasodilators that can be used. Many units still regard epinephrine as an inotrope of choice and use its predominant beta agonist effect in the dose range of 0.02 to 0.04 mg/kg/minute. Some prefer dobutamine and others a combination of inotrope and vasodilator or an inodilator. Phosphodiesterase inhibitors can be useful in certain situations such as pre-existing ventricular dysfunction or when stunning of the myocardium is suspected with down regulation of beta receptors. Dopamine is useful in the renal vasodilating dose to improve renal perfusion and improve output. There is no ideal inotrope at present and each one has its own drawbacks. The clinician must learn to use the inotropes (especially the newer ones) based on his own clinical experience.

Importance of venting the left ventricle in aortic valve surgery.

Routine use of left ventricular vent is controversial in patients undergoing open heart surgery. However, surgeons use it during valvular surgery to maintain a dry field to make the operation easier. In addition it helps to prevent left ventricular distention during the critical period of rewarming and reperfusion, if ventricular function does not return immediately following the release of aortic cross clamp. In our country, patients present for valvular surgery at a very late stage and they often have severe left ventricular hypertrophy. This may affect the return of cardiac rhythm after the release of aortic cross clamp with progressive left ventricular distention. In the authors' experience, insertion of left ventricular vent through the apex is occasionally necessary to decompress the left ventricle as the left atrial vent usually fails to do so. This paper deals with retrospective analysis of the seven patients (out of a total of 395 patients who underwent valve surgery) who required insertion of left ventricular vent through the apex and reviews the beneficial effects of an apical left ventricular vent under refractory circumstances. It is recommended that insertion of left ventricular vent through apex should be strongly considered in patients having severe aortic valve disease with hypertrophied hearts, if cardiac rhythm in not restored with conventional management with left atrial vent and 3 to 5 DC shocks following the release of aortic cross clamp.

Control of tachycardia and hypertension following coronary artery bypass graft surgery: efficacy and haemodynamic effects of esmolol.

Hypertension following coronary artery bypass grafting is not uncommon, especially in patients having good left ventricular function. It is often accompanied by tachycardia. The purpose of this study is to determine the efficacy of esmolol in the treatment of tachycardia and hypertension immediately following cardiopulmonary bypass and to study other haemodynamic effects of esmolol. Thirty patients undergoing elective [corrected] coronary artery bypass grafting were included in this prospective study. Morphine-based anaesthetic technique along-with standard bypass techniques were used in all the patients. The study was performed in the operating room about 30-45 minutes after the termination of cardiopulmonary bypass. Patients having a heart rate of more than 90 bpm and systolic blood pressure of more than 130 mm Hg without any inotropic support were included and randomly assigned to esmolol or control group. Esmolol was administered in a bolus dose of 500 micrograms/kg followed by infusion of upto 100 micrograms/kg/min. The patients in the control group were administered comparable volumes of normal saline. Baseline haemodynamic measurements were obtained just before the administration of esmolol or normal saline and were repeated after 5, 10, 15, 30 and 45 min. The baseline measurement in both the groups showed that patients were maintaining a state of hyperdynamic circulation with high systolic blood pressure (esmolol group 148 +/- 15 mm Hg, control group 140 +/- 8 mm Hg; p = NS), heart rate (esmolol group 128 +/- 17 bpm, control group 127 +/- 17 bpm; p = NS) and cardiac index (esmolol group 3.1 +/- 1 L/min/m2, control group 3.3 +/- 0.5 L/min/m2; p = NS). Esmolol decreased systolic blood pressure (p < 0.001), heart rate (p < 0.01) and cardiac index (p < 0.05) at five minutes. These changes persisted throughout the study period. The left ventricular stroke work index decreased at five minutes (p < 0.05) and remained so till 30 minutes. The maximum fall in heart rate (15%) and systolic blood pressure (16%) was observed at 45 minutes. There were no haemodynamic changes in the control group except that cardiac index, stroke volume and left ventricular stroke work index increased at five minutes. We conclude that esmolol lowers the indices of cardiovascular work in patients who demonstrated hyperdynamic circulation. This was achieved by decreasing the heart rate and systolic blood pressure which was accompanied by decrease in cardiac index and left ventricular stroke work index.

Haemodynamic effects of leg raising in patients undergoing coronary artery bypass grafting.

Twenty patients undergoing elective coronary artery bypass grafting were studied prospectively to evaluate the haemodynamic effects of passive leg raising. The patients were divided into two groups: those having good left ventricular function with ejection fraction of 0.50 or more (group I, n = 10) and those having poor left ventricular function with ejection fraction of upto 0.35 (group II, n = 10). Morphine-based anaesthetic technique was used and standard haemodynamic measurements were obtained at following stages: (1) control--20 to 30 min after induction of anaesthesia; (2) one minute, and (3) five min after raising both the legs; (4) one min, and (5) five min after the legs were repositioned. In group I, heart rate decreased from 71 +/- 9 to 66 +/- 8 beats/min (p < 0.001) at stage 1 and persisted throughout the study period. This was accompanied by a decrease in cardiac index, although, the statistical significance was achieved at stage 3 and 4 only. The haemodynamic changes observed in group II were of more severe magnitude. The heart rate decreased from 90 +/- 13 to 84 +/- 13 beats/min at stage 1 (p < 0.05) and persisted throughout the study with maximum decrease of 14 percent occurring at stage 3. The cardiac index decreased significantly from 2.4 +/- 0.3 to 2.0 +/- 0.5 L/min/m2 (p < 0.05) at stage 1. This persisted throughout the study except that it recovered at stage 4. The maximum decrease in cardiac index (20%) occurred at stage 2. In addition, systemic vascular resistance increased significantly from 1458 +/- 255 to 1830 +/- 420 dyne.sec.cm-5 (p < 0.05) at stage 1 and persisted throughout the study period. We conclude that passive leg raising should be undertaken with caution in patients with coronary artery disease especially in those who have poor left ventricular function.

Emergency mitral valve replacement for traumatic mitral insufficiency following balloon mitral valvotomy: an early haemodynamic study.

Acute severe mitral insufficiency may occur during percutaneous transvenous balloon mitarl valvotomy. Urgent surgical intervention in the form of mitral valve repair or replacement may be necessary in these patients. The haemodynamic measurements at various stages in these patients were obtained and compared with those of patients undergoing elective mitral valve replacement for chronic mitral regurgitation. Between September 1995 and December 1947, urgent mitral valve replacement was performed in 14 patients out of a total of 1688 patients who underwent balloon mitral valvotomy. Haemodynamic measurements could be obtained in 7 of these patients and they constituted group I. Eight other patients undergoing elective mitral valve replacement during the same period for chronic mitral regurgitation constituted group II. Standard haemodynamic measurements were obtained at the following stages: (1) Baseline- 20-30 min after endotracheal intubation; (2) stage 1- 20-30 min after termination of the cardiopulmonary bypass: (3) stage 2- four hours after the patient was transferred to ICU and (4) stage 3-30 min after extubation. All the patients were suffering from severe pulmonary hypertension. However, the indices of pulmonary artery hypertension such as mean pulmonary artery pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance as well as right ventricular systolic and end-diastolic pressures did not decrease after surgery in group I. In contrast, in group II, there was significant decrease in mean pulmonary artery pressure (p<0.05), pulmonary capillary wedge pressure (p<0.05), right ventricular systolic (p<0.001) and end-diastolic pressures (p<0.05) at stage 1. These changes persisted throughout the study period. Pulmonary vascular resistance showed a decreasing trend, but attained statistical significance at stage 1 only. Two patients died; one of intractable cardiac failure and another from septicaemia and multiple organ failure in group I, but there were no deaths in group II. Reactive pulmonary hypertension secondary to acute mitral regurgitation may not recover immediately following mitral valve replacement and may be responsible for poor outcome in these patients.

Bacteriological Profile of Patients Undergoing Open Heart Surgery and Evaluation of a Bacterial Filter using Protected Broncho-Alveolar Lavage.

Twenty seven patients undergoing elective open heart surgery were included in this prospective study. They were randomly divided into two groups. Group C (n = 12) constituted the control group in whom no breathing filter was used in the anaesthesia circuit in the operating room or in the ICU. Humidification of breathing gases was achieved with the help of conventional heated humidifier. In group F (n = 15), heat and moisture exahanging bacterial / viral filter was incorporated in the breathing circuit at the patient end between the catheter mount and Y connection of the breathing circuit. In both the groups, samples of throat swab, protected broncho-alveolar lavage with double catheter and Ryles tube aspirate were collected preoperatively (in the operation theatre) and postoperatively (in the Intensive Care Unit on day 1). All the samples were sent to the laboratory immediately after the collection for Gram staining and culture and sensitivity. Pathogenic organisms were isolated from a total of 9 patients (33%) preoperatively. Exogenous spread of the organisms to the lungs was considered to have occurred if new pathogenic organisms were isolated from the postoperative bronchoalveolar lavage and the simultaneous samples of the throat swab and Ryles tube did not contain the same organism. By this definition, the exogenous spread of the organisms occurred in one patient in group C and in no patient in group F (P = 0.46, Fishers test). The commonest organisms isolated were Staphylococcus aureus, Klebsiella sp. and Pseudomonas sp. We conclude that colonization of the pathogenic organisms is common (33%) in orophrynx and gastrointestinal tract in hospitalized patients. There was no difference in the exogenous spread of the organisms between the two groups. The unity of the filter, therefore, appears to be limited to prevent contamination of anaesthesia machines or ventilators as has been shown by earlier studies.

Anaesthetic management of patients undergoing surgery for tachyarrhythmias. Initial experience with 16 patients.

Sixteen patients suffering from various cardiac arrhythmias were treated surgically. Intraoperative computerised electrophysiologic mapping was used in 14. Thirteen patients were suffering from Wolff-Parkinson-White syndrome. They underwent surgical division or cryoablation of accessory pathways. Two patients who had rheumatic mitral stenosis with left atrial clot underwent "Maze III" procedure with open mitral commissurotomy and clot removal. One patient with paroxysmal refractory ventricular tachycardia and a left ventricular aneurysm had an aneurysmectomy with subendocardial resection of the arrhythmic focus. All antiarrhythmic medications were discontinued preoperatively. Morphine was the principal anaesthetic agent, supplemented with halothane. Muscle relaxation was provided with pancuronium bromide. The various problems encountered included hypotension and arrhythmia during placement of epicardial band array for mapping (4 patients), ventricular tachycardia during internal jugular vein cannulation (1 patient) and continuance of delta wave after cryoablation in 2 patients. Halothane may have interfered with electrophysiologic mapping and accurate localization of accessory pathway leading to persistence of delta wave. The choice of anaesthetic agents should be guided by the electrophysiologic effects and potential influence of these agents on the accessory pathways.

Blood conservation in valve surgery.

Blood utilization in 40 patients undergoing elective valve surgery was prospectively studied. The patients had valvular lesions of rheumatic origin with a mean age of 29.1 years and a mean preoperative hematocrit of 35.23 +/- 4.16. Blood was removed from all patients after induction of anesthesia and reinfused after bypass (mean 365.12 +/- 66.96 ml). Membrane oxygenator was used in all the patients. All discard suction was routed through a regionally heparinised collecting and processing system, and the resulting red cell concentrate was transfused. At the conclusion of bypass, all blood remaining in the pump oxygenator was also processed by cell saver and used for subsequent reinfusion. Normovolemic anemia was accepted in hemodynamically stable patients. Thirty two patients (80%) received no bank blood or blood products during their entire hospital course. A total of twelve units of whole blood was transfused into eight patients.

Mechanical ventilation after open heart surgery.

One hundred adult patients, undergoing elective open heart surgery over a period of 4 months, were studied to assess the practice of ventilation in the post operative period. The anaesthetic technique employed used moderate doses of morphine, supplemented with halothane and a muscle relaxant. The decision to extubate was based on clinical assessment, and satisfactory blood gases following a 45 minute T-piece trial. The patients were ventilated for an average duration of 8 hours and 2 minutes and 59 out of 100 patients were extubated within 8 hours. Patients undergoing coronary artery bypass graft were ventilated for significantly longer durations (10 hours 28 minutes) (p < 0.05) and had significantly lower arterial oxygen tension (p < 0.01) 30 minutes after extubation, as compared with those undergoing valvular surgery. Also patients whose bypass time exceeded 2 hours had significantly longer extubation times (p < 0.05) as compared with those who had a bypass time less than 1 hour. T piece trial was found to be a satisfactory method of weaning in all the patients.

Cannulation of the internal jugular vein in patients undergoing open heart surgery.

A total of 476 internal jugular vein cannulations performed between June 1990 to August 1991 were prospectively evaluated. The patients' age ranged between ten days to 61 years. We achieved a high success rate of cannulation (97.9%). We describe the use of two single lumen catheters inserted through right internal jugular vein as an alternative to the popular multilumen catheters. We also suggest that low approach should be tried more often in children, if the central approach fails.

Surgical management of cardiac myxomas.

Cardiac myxomas are rare cardiac lesions, though they are the commonest tumours of the heart. Seventeen cases of cardiac myxomas have been operated during the last one decade. Exertional dyspnoea, palpitation and chest pain were the main presenting symptoms. Echocardiographic assessment was the only definitive diagnostic investigation required prior to surgery. Early surgical excision was planned in all the cases. Irrespective of the exposure techniques, removal of the tumour with wide excision of its base was practised. There was one early death due to low cardiac output in a patient brought in a shock like state. Follow up study has revealed 14 patients in NYHA class I and two patients are having class II symptoms. Periodic echocardiographic follow up study has not revealed any recurrence till date. It is concluded that an early diagnosis and surgery gives excellent long term results in these cases.

Immunological alterations following open heart surgery.

Immunological changes in thirty patients undergoing various cardiac surgical procedures (twenty patients undergoing open heart surgery with either the bubble or the membrane oxygenator and ten patients undergoing closed surgical procedures) were studied. There was an activation of suppressor T cells and secretion of lymphokines in patients undergoing open heart surgery with activation of the classical complement pathway. The immunological alterations were similar in all patients irrespective of the type of oxygenator used.