Evaluation and comparison of early hemodynamic changes after elective mitral valve replacement in patients with severe and mild pulmonary arterial hypertension.

OBJECTIVE: To evaluate and compare early hemodynamic changes after elective mitral valve replacement (MVR) in patients with severe and mild pulmonary arterial hypertension (PAH). DESIGN: A prospective observational study. SETTING: University-affiliated hospital. PARTICIPANTS: Sixty patients undergoing elective MVR. INTERVENTIONS: The patients were divided into 2 equal groups based on the presence (group A) or absence (group B) of severe PAH defined as systolic pulmonary artery pressure (PAP) > or = 50 mmHg on preinduction pulmonary artery catheterization. Thiopental, fentanyl, midazolam, isoflurane, and rocuronium (or vecuronium if the heart rate >100 beats/min) were used for the induction and maintenance of anesthesia. MVR was performed using standard cardiopulmonary bypass (CPB) techniques. The therapy for PAH was electively instituted in all patients with a nitroglycerin infusion (0.5-1 microg/kg/min), deliberate hypocarbia (arterial carbon dioxide tension < or = 35 mmHg), fractional inspired oxygen concentration = 1.0, and elective ventilation for at least 12 hours in the postoperative period. Hemodynamic and arterial blood gas parameters were serially measured before induction; after intubation; after termination of CPB; after extubation; and at 6, 24, and 48 hours after surgery. Differences in these parameters were analyzed within and among the groups using appropriate statistical tests. MEASUREMENTS AND MAIN RESULTS: The mean CPB and aortic cross-clamp times were similar in the 2 groups (78 +/- 33 and 50 +/- 21 minutes in group A and 63 +/- 32 and 41 +/- 23 minutes in group B). The mean PAP, pulmonary capillary wedge pressure, and pulmonary vascular resistance decreased significantly soon after CPB in both groups (p < 0.001), but the decrease was significantly lower in group A (p < 0.001). The mean PAP approached near-normal values in group A (23 +/- 8 mmHg) and normal values in group B (16 +/- 6 mmHg) immediately postoperatively. There was an increase in cardiac index (p < 0.01) after CPB in group A. A relative improvement in oxygenation occurred after MVR in group A compared with group B (p < 0.001). Patients in group A were ventilated for a longer duration (25.9 +/- 18.8 v 17.3 +/- 7.9 hours, p < 0.05). There was no significant difference in the inotropic requirement between the 2 groups. There was no mortality in either group. CONCLUSIONS: PAP returns to near-normal values in patients with severe preoperative PAH and to normal values in patients with mild preoperative PAH immediately after MVR. The outcome after surgery in patients with severe PAH is comparable to those with mild PAH.

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.

Balloon mitral commissurotomy: an intraoperative assessment.

OBJECTIVE: Advances in balloon catheter technology have revolutionized the management of obstructive cardiovascular diseases. For lesions like mitral stenosis, balloon commissurotomy has emerged as an alternative to surgical relief showing definite functional benefits in a few clinical trials, albeit with variable results. Such variability necessitated objective evaluation of the efficacy of balloon mitral commissurotomy. METHODS: The balloon mitral commissurotomy was carried out in 11 patients suffering from isolated mitral stenosis, under vision in a surgical setting. All patients were in NYHA class III/IV. Initially single balloon was used for mitral commissurotomy followed by double balloon, before completing the mitral valvotomy with surgical instruments whenever required. The commissural split was measured by firmly stretching the two commissures using nerve hooks and measuring the distance between the two hooks with the help of a caliper. Assessment of balloon dilation was made by calculating exact percentage of residual commissural split following balloon dilation as compared with completed mitral valvotomy. The exact percentage of commissural split was thus obtained by subtracting residual commissural split following balloon dilation from commissural split obtained after surgical open mitral valvotomy. RESULTS: Complete commissurotomy using the balloon technique was possible in two (18.2%) patients. In the remaining nine (81.8%) patients, balloon expansion provided only 50% to 80% of commissural split and required instrumental completion with good results. CONCLUSIONS: Balloon mitral commissurotomy, by virtue of its circumferential force, helps to develop a good cleavage and attains good hemodynamic improvement which may be life saving in critical mitral stenosis in selected group of patients with pliable mitral leaflets and minimal subvalvular pathology.

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.

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.

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.

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.

Healed perivalvular abscess: Incidental finding on transesophageal echocardiography [corrected].

A 36-year-old male patient presented with the complaints of palpitations and breathlessness. Preoperative transthoracic echocardiography (TTE) revealed a bicuspid aortic valve; severe aortic regurgitation with dilated left ventricle (LV) and mild LV systolic dysfunction (ejection fraction 50%). He was scheduled to undergo aortic valve replacement. History was not suggestive of infective endocarditis (IE). Preoperative TTE did not demonstrate any aortic perivalvular abscess. Intraoperative transesophageal echocardiography (TEE) examination using the mid-esophageal (ME) long-axis view, showed an abscess cavity affecting the aortic valve, which initially was assumed to be a dissection flap, but later confirmed to be an abscess cavity by color Doppler examination. The ME aortic valve short-axis view showed two abscesses; one was at the junction of the non-coronary and left coronary commissure and the other one above the right coronary cusp. Intraoperatively, these findings were confirmed by the surgeons. The case report demonstrates the superiority of TEE over TTE in diagnosing perivalvular abscesses.

Pulmonary artery catheter placement in high-risk coronary artery bypass grafting: should it be done before or after induction of anaesthesia?

Pulmonary artery catheter (PAC) is generally inserted after induction of general anaesthesia (GA). However, in high-risk coronary artery disease patients (left main disease / ejection fraction (35%), it may be desirable to insert it before the induction of GA. Thirty patients with left main coronary artery disease and / or left ventricular ejection fraction < 35% undergoing coronary artery bypass grafting (CABG) surgery were prospectively randomized into 2 groups of 15 each. In group A, pulmonary artery catheter was inserted before induction and in group B, after induction of GA. Haemodynamic parameters like heart rate (HR), mean arterial pressure (MAP), cardiac index (CI) and other derived parameters were obtained serially up to 10 min after tracheal intubation in group A and the haemodynamic management was based on these parameters. In group B, the haemodynamic management was based on HR and MAP. The demographic data was similar in both the groups. The time required for insertion of PAC was also similar in the two groups (7.6 +/- 1.8 and 6.2 +/- 1.3 min, p > 0.05). The number of interventions in the form of infusions of volume, nitroglycerin or dopamine were significantly more in group A before tracheal intubation. The patients in group A maintained better haemodynamics at 10 min after tracheal intubation as compared with group B (CI 2.8 +/- 0.67 vs 2.1 +/- 0.49, p < 0.05; stroke volume 54 +/- 18 vs 51 +/- 0.65, p < 0.05; systemic vascular resistance 1431 +/- 409 vs 1724 +/- 430, p < 0.05; pulmonary vascular resistance 109 +/- 34 vs 181 +/- 110, p < 0.05). Insertion of PAC before induction of GA provides informative data and can be utilized to treat haemodynamic alterations in high-risk patients undergoing CABG.

Length of insertion for pulmonary artery catheters to locate different cardiac chambers in patients undergoing cardiac surgery.

BACKGROUND: Although, guidelines related to length of insertion of a pulmonary artery catheter to reach a particular cardiac chamber are available, these are not backed by clinical studies. We measured the length of insertion of pulmonary artery catheters to locate the right ventricle, pulmonary artery and pulmonary capillary wedge positions in 300 adult patients undergoing elective cardiac surgery. METHODS: The pulmonary artery catheters were inserted using a standard technique through the right internal jugular vein. The right ventricle, pulmonary artery and wedge position of the catheter were confirmed by the characteristic waveforms, and the length of insertion to these points was measured. RESULTS: The right ventricle was reached at 24.6 (3) cm (95% CI 24.2-24.9 cm), pulmonary artery at 36 (4) cm (95% CI 35.6-36.5 cm) and wedge position at 42.8 (5.7) cm (95% CI 42.2-43.5 cm). The length of catheter to reach the right ventricle, pulmonary artery and wedge position was significantly more in patients undergoing valve surgery as compared with those undergoing coronary artery bypass grafting [26 (3.8) and 24 (2.5) cm; 38.5 (4.6) and 35 (3.2) cm; and 47.8 (6.9) and 41.2 (4.1) cm, respectively, P<0.001]. The length of insertion to reach pulmonary artery and pulmonary capillary wedge position was directly related to height of the patient (Pearson's correlation 0.157 and 0.15, respectively). CONCLUSIONS: We have provided the norms related to length of insertion of pulmonary artery catheter, which should be useful in accurate placement of the catheter and minimize complications related to coiling of the catheter.

Effect of muscle relaxants on heart rate, arterial pressure, intubation conditions and onset of neuromuscular block in patients undergoing valve surgery.

Sixty six patients undergoing elective valve surgery were randomized to receive rocuronium bromide 0.6 mg/Kg (Group R, n=22), pancuronium bromide 0.1 mg/Kg (Group P, n= 22) and vecuronium bromide 0.1 mg/Kg (Group V, n=22), Measurements of heart rate and arterial pressure (systolic, diastolic and mean) were noted at the following stages: 1) baseline when haemodynamics were stable for 2 minutes after induction of anaesthesia (2) one, (3) three, (4) five minutes after administration of muscle relaxants, (5) One, (6) three, and (7) five minutes after intubation. In group R, the heart rate decreased 5 min after injection of muscle relaxant from 93.9 +/- 21.3 to 82.4 +/- 20.7 beats/min (p<0.001). However, it increased to 128.3 +/- 25.8 beats/min (p<0.001) following intubation and returned to baseline at 5 min after intubation. In group P, heart rate increased from 98.8 +/- 32.6 to 109.6 +/- 32.7 beats/min (p<0.001), 1 min after injection of pancuronium and this increase persisted throughout the study period. In group V, heart rate decreased from 99.9 +/- 22.3 to 83.8 +/-19.6 beats/min (p<0.001) at 5 min after injection of the drug. It increased to 118.6 +/- 22.4 beats/min (p<0.001), 1 min after intubation and returned to baseline at 5 min after intubation. The decrease in heart rate in group R and V was accompanied by a significant decrease in systolic, diastolic and mean arterial pressure. In group P, only the systolic pressure decreased significantly at 5 min after injection of the drug. Intubation was accompanied by a significant increased in systolic, diastolic and mean arterial pressure in all the groups. Excellent intubation conditions (intubation score 3-4) were observed with all the three drugs, however, there were number of patients in group P who showed diaphragmatic movement during intubation. Onset of action of muscle relaxant, was fastest with rocuronium (group R=132.7 +/- 0.3 sec, P=182.6 +/- 68.5 sec, V= 144.8 +/- 46.1 sec, Group P vs Group R). To conclude, pancuronium causes significant increase in heart rate and should be preferred in patients with regurgitant lesions having slower baseline heart rate. Vecuronium and rocuronium decrease the heart rate and should be preferred in patient with faster baseline heart rate. In terms of intubating conditions rocuronium and vecuronium provide best conditions, but onset is faster with rocuronium.

Surgical interventions in patients undergoing percutaneous balloon mitral valvotomy: a retrospective analysis of anaesthetic considerations.

Between 1990 and 2000, 5499 balloon mitral valvotomies were performed at GB Pant Hospital. Amongst these, 45 patients required surgical intervention, which form the basis of this report. There were 18 males and 27 females with the mean age of 26.5+/-8.3 years and weight of 42.9+/-7.39 kg. Thirty-five patients underwent open-heart surgery and 10 closed-heart surgery. Twenty-five patients developed acute severe mitral regurgitation during balloon mitral valvotomy and required emergency open-heart surgery. Morphine based anaesthetic technique with careful attention to haemodynamic monitoring was used in these patients. All patients required a high inotropic support to terminate the cardiopulmonary bypass. The closed-heart surgical procedures included emergency exploration for cardiac tamponade (4), exploration + closed mitral valvotomy (4), and elective closed mitral valvotomy (2). The overall mortality was 9%, which is much higher than the reported mortality for elective mitral valve replacement. Morphine based anaesthetic technique is useful in these patients. Adequate oxygenation, vasodilators, inotropes and diuretics are required for preoperative stabilisation of patients who develop acute mitral regurgitation, while those who develop cardiac tamponade need volume replacement along with inotropes and immediate surgical decompression of the tamponade.

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.

Atrial ECG as a guide to the placement of central venous catheter in patients undergoing Open Heart Surgery.

Hundred adults undergoing open heart surgery were randomized into two equal groups. In group I (n=50), surface anatomical landmarks and in group II (n=50) atrial ECG was used as a guide for correct placement of the central venous catheter (within 1 cm of superior vena cava - right atrial junction). The position of the catheter tip was confirmed by direct palpation by the surgeon on the operating table and by radiological examination in the post operative period. Surgeon's assessment revealed that the catheter was successfully placed in 32 (69.6%) patients in group II and 25 (50%) patients in group I (p=NS). Radiological examination revealed that the catheter was successfully placed in 31 (67.4%) patients in group II and in 28 (57.1%) patients in group I (p=NS). Amongst the unsuccessful placements right atrial placement was present in 5 patients (10%) in group I and 7 patients (15.2%) in group II by surgeon's assessment and 8 patients (16.3%) in group I and 9 patients (9.6%) in group II by radiological examination (p=NS) No complications related to intracardiac placement occurred in any of the patients. We conclude that atrial ECG is a promising technique for central venous catheter placement, although it did not significantly increase the correct placement in this study. This may be due to alteration in the relationship of sino-atrial node and superior vena cava - right atrial junction in patients with cardiac disease. Further studies defining the correct technique of insertion, (especially in cardiac patients) are necessary to improve the success rate.