Positron emission tomography with f18-fluorodeoxyglucose in the staging and preoperative evaluation of malignant pleural mesothelioma.

OBJECTIVES: The purpose of this study was to evaluate the utility of positron emission tomography with F18-fluorodeoxyglucose in the preoperative evaluation and staging of malignant mesothelioma in patients who were candidates for aggressive combined modality therapy. METHODS: Eighteen consecutive patients with biopsy-proven malignant mesothelioma underwent positron emission tomographic scanning. The results of positron emission tomographic imaging were compared with results obtained by computed tomography, mediastinoscopy, thoracoscopy, and pathologic examination of surgical specimens. All patients fasted and received an average of 14.5 +/- 2.7 mCi of F18-fluorodeoxyglucose for positron emission tomographic scanning. Attenuation-corrected whole-body and regional emission images of the chest and upper abdomen were acquired and formatted into transaxial, coronal, and sagittal images. RESULTS: All primary malignant mesotheliomas accumulated F18-fluorodeoxyglucose, and the mean standardized uptake value was 7. 6 (range, 3.33-14.85; n = 9). There were no false-negative results of positron emission tomography. Identification of occult extrathoracic metastases by positron emission tomography was the basis for excluding two patients from surgical therapy. There were two false-positive results of positron emission tomography: increased F18-fluorodeoxyglucose uptake in the contralateral chest that was negative by thoracoscopic biopsy (n = 1) and increased abdominal F18-fluorodeoxyglucose uptake after partial colectomy for diverticular disease (n = 1). CONCLUSIONS: Positron emission tomography can identify malignant pleural mesothelioma and appears to be a useful noninvasive staging modality for patients being considered for aggressive combined modality therapy.

Ventricular contraction abnormalities in dilated cardiomyopathy: effect of biventricular pacing to correct interventricular dyssynchrony.

OBJECTIVE: To measure ventricular contractile synchrony in patients with dilated cardiomyopathy (DCM) and to evaluate the effects of biventricular pacing on contractile synchrony and ejection fraction. BACKGROUND: Dilated cardiomyopathy is characterized by abnormal ventricular activation and contraction. Biventricular pacing may promote a more coordinated ventricular contraction pattern in these patients. We hypothesized that biventricular pacing would improve synchrony of right ventricular and left ventricular (RV/LV) contraction, resulting in improved ventricular ejection fraction. METHODS: Thirteen patients with DCM and intraventricular conduction delay underwent multiple gated equilibrium blood pool scintigraphy. Phase image analysis was applied to the scintigraphic data and mean phase angles computed for the RV and LV. Phase measures of interventricular (RV/LV) synchrony were computed in sinus rhythm and during atrial sensed biventricular pacing (BiV). RESULTS: The degree of interventricular dyssynchrony present in normal sinus rhythm correlated with LV ejection fraction (r = -0.69, p < 0.01). During BiV, interventricular contractile synchrony improved overall from 27.5 +/- 23.1 degrees to 14.1 +/- 13 degrees (p = 0.01). The degree of interventricular dyssynchrony present in sinus rhythm correlated with the magnitude of improvement in synchrony during BiV (r = 0.83, p < 0.001). Left ventricular ejection fraction increased in all thirteen patients during BiV, from 17.2 +/- 7.9% to 22.5 +/- 8.3% (p < 0.0001) and correlated significantly with improvement in RV/LV synchrony during BiV (r = 0.86, p < 0.001). CONCLUSIONS: Dilated cardiomyopathy with intraventricular conduction delay is associated with significant interventricular dyssynchrony. Improvements in interventricular synchrony during biventricular pacing correlate with acute improvements in LV ejection fraction.

Improved evaluation of the location and mechanism of mitral valve regurgitation with a systematic transesophageal echocardiography examination.

UNLABELLED: Mitral regurgitation (MR) is a major determinant of outcome in cardiac surgery. The location and mechanism of mitral lesions determine the approach to various repairs and their feasibility. Because of incomplete evaluations or change in patient condition, detailed intraoperative transesophageal echocardiography (TEE) examination of the mitral valve may be required. We hypothesized that a systematic TEE mitral valve examination would allow precise identification of the anatomic location and mechanism of MR in patients undergoing mitral surgery. We designed a systematic mitral valve examination consisting of six views: five-chamber, four-chamber, two-chamber anterior, two-chamber mid, two-chamber posterior and short-axis. We used this examination prospectively in 13 patients undergoing mitral valve surgery for severe MR and compared the results with the surgical findings. We then retrospectively interpreted 11 similar patients who had undergone intraoperative TEE studies before this examination. TEE correctly diagnosed the mechanism and precise location of pathology in 12 of 13 patients in the prospective group, but in only 6 of 10 patients in the retrospective group. TEE also correctly identified 75 of 78 mitral segments (96%) as being normal or abnormal. In the retrospective group, only 42 of 60 segments (70%) were correctly identified (P < 0.001). We conclude that this systematic TEE mitral valve examination improves identification of mitral segments and precise localization of pathologies and may also improve the diagnosis of the mechanism of MR. IMPLICATIONS: In this article, we describe how a systematic examination of the mitral valve by using transesophageal echocardiography allows identification of the different segments of the mitral valve, precise localization of pathology, and helps to diagnose the mechanism of mitral regurgitation. This is important in determining an approach to mitral valve repair and its feasibility.

Maze procedure and homograft replacement of a rheumatic mitral valve.

A 64-year-old woman presented with congestive heart failure due to severe mitral valve stenosis and chronic atrial fibrillation. A Maze III procedure was performed, and the mitral valve replaced with a mitral homograft. Postoperatively, the patient regained normal sinus rhythm, had trivial mitral regurgitation, regained her atrial transport function, and had improved myocardial function.

Pulmonary metastases of endocrine origin: the role of surgery.

PURPOSE: To determine the clinical course and outcome of patients undergoing pulmonary resection for metastatic endocrine tumors. METHODS: Retrospective review of 47 patients with known endocrine tumors and pulmonary metastases who were evaluated for surgical resection between 1975 and 1996. RESULTS: Tumors evaluated included the following: carcinoid (16), thyroid (12), pancreatic adenocarcinoma (10), adrenocortical carcinoma (6), pheochromocytoma (2), and parathyroid (1). Thirty-three patients were asymptomatic. Hormone secretion was noted in five patients. Twenty-five patients, who had isolated lung metastases, good control of the primary tumor, and no medical contraindication had surgical resection. The number of pulmonary nodules was not a limiting factor as long as all disease could be resected with adequate residual pulmonary function. CT was successful in directing resection in all patients. Twenty-six operations were performed in 25 patients and 22 patients were treated medically. Wedge resection was performed for lesions <2 cm (15), and lobectomy for larger or multiple nodules (10). Four patients had bilateral nodules resected. There was no operative mortality and no major complications. Actuarial 5-year survival was 61% for surgically treated patients. Independent predictors of poor survival included positive mediastinal lymph nodes at time of surgery (p=0.004) and shorter disease-free interval (p=0.01). At a median of 6.7+/-1.2 years, six patients have developed radiographic appearance of a recurrence. A single patient with recurrent Hürthle cell cancer has had a successful reresection. The remaining patients have received chemotherapy. No patient with pancreatic carcinoma or adrenocortical carcinoma was a candidate for resection. All medically treated patients died within 6 months. CONCLUSION: Patients with endocrine tumors and pulmonary metastases are usually asymptomatic, their conditions are diagnosed accurately with CT, and they can achieve long-term survival comparable to other tumors (sarcoma) after pulmonary metastasectomy. CLINICAL IMPLICATIONS: Patients with carcinoid, thyroid, pheochromocytoma, and parathyroid tumors with pulmonary metastases should undergo surgical resection if there is the following: (1) no evidence of extrathoracic disease; (2) good control of the primary tumor; (3) no medical contraindications for surgery; and (4) pulmonary function that can tolerate resection of all documented disease. The role of adjuvant chemotherapy in patients with positive lymph nodes needs further study.

Cardiac valve surgery in octogenarians: improving quality of life and functional status.

BACKGROUND: Although cardiac valve procedures are being performed more frequently in the elderly, long-term functional outcomes have not been well characterized. OBJECTIVE: To evaluate changes in quality of life and functional status in octogenarians after cardiac valve surgery. DESIGN: Retrospective medical record review and patient telephone interview. Median follow-up 30 months (range, 6-95 months). SETTING: Tertiary care university hospital. PATIENTS: Octogenarians undergoing cardiac valve surgery (N = 61; mean age, 83.5 years; range, 80-89 years). INTERVENTIONS: Forty-seven patients had aortic valve replacement, 14 had mitral valve replacement and/or repair, and 27 had a combined procedure with coronary artery bypass grafting. OUTCOMES: Actuarial survival, morbidity, length of hospital stay, and discharge disposition were evaluated. Functional status, using the New York Heart Association classification, and Karnofsky performance status were evaluated preoperatively and postoperatively at 1 and 3 months after hospital discharge. RESULTS: Operative (<30 days) mortality occurred in 7 (11.4%) of 61 patients. Preoperative intensive care unit stay (P < .001) and New York Heart Association class 4 (P < .02) were independent predictors of early death by multivariable analysis. Among hospital survivors, there were no major complications in 34 patients (63%), and this group had a mean (+/- SD) postoperative hospital stay of 12.2 +/- 5.5 days. Twenty patients (37%) incurred significant complications, the most common of which were bleeding, pneumonia, and renal insufficiency. The mean (+/- SD) postoperative hospital stay in this group was 25 +/- 17 days. Although significant complications were associated with an increased postoperative stay, this was not predictive of disposition to a skilled nursing facility or the final score on the postoperative Karnofsky performance scale. Actuarial survival was 85% at 1 year and 66% at 5 years. Patients with perioperative complications had significantly decreased actuarial survival by the Cox proportional hazards regression model (P < .001). Among hospital survivors, the score on the Karnofsky performance scale 1 month after discharge had improved 50% from a preoperative median score of 30% (severely disabled, requiring special care) to a postoperative median score of 80% (being able to perform normal activity with only moderate symptoms). The New York Heart Association classification improved a median of 2 classes in this group. These benefits were sustained at the 3-month follow-up. CONCLUSION: Although greater resource expenditure is required for the initial perioperative convalescence, octogenarians can be expected to have an excellent functional outcome and long-term performance status after cardiac valve surgery.

Acute effects of intraoperative multisite ventricular pacing on left ventricular function and activation/contraction sequence in patients with depressed ventricular function.

INTRODUCTION: We hypothesized that simultaneous right and left ventricular apical pacing would result in improvement in left ventricular function due to improved coordination of segmental ventricular contraction. Structural changes in ventricular muscle present in dilated cardiomyopathy compromise ventricular excitation and mechanical contraction. METHODS AND RESULTS: Eleven patients with depressed left ventricular function having cardiac surgery underwent epicardial multisite pacing with continuous transesophageal echocardiographic imaging. Quantitative measurement of percent fractional area change was performed, and segmental changes in contraction sequence resulting from simultaneous right and left ventricular pacing were assessed by application of phase analysis to recorded transesophageal images. There was no statistically significant difference between the paced QRS duration achieved with simultaneous right and left ventricular apical pacing and the native QRS duration (139+/-39 msec vs 106+/-18 msec, P = NS), but all other paced modes resulted in longer QRS durations. Percent fractional area change improved with simultaneous right and left ventricular apical pacing but not with other paced modes (41.5+/-11.9 vs 34.3+/-9.7, P < 0.01). Phase analysis demonstrated a resequencing of segmental left ventricular activation/contraction when compared to baseline ventricular activation. CONCLUSION: Simultaneous right and left ventricular apical pacing results in acute improvements in global ventricular performance in patients with depressed ventricular function. Improvements may result from pacing-induced global coordination through recruitment of left and right ventricular apical and septal segments critical to effective ventricular contraction.

Evaluation of thoracic aortic dissection using breath-holding cine MRI.

OBJECTIVE: Our goal was to determine if breath-hold cine MRI in transaxial planes can be used for the evaluation of thoracic aortic dissection instead of conventional cine MRI since rapid imaging is required in this clinical setting. MATERIALS AND METHODS: Twelve patients with thoracic aortic dissection were imaged using a 1.5 T imager. Breath-hold images were acquired with fast cine MR sequence (TR/TE = 9/2.8, 20 degrees flip angle) using segmented k-space data acquisition. Conventional non-breath-hold cine MR images (TR/TE = 22/7.5, 35 degrees flip angle, 2 averages) were taken with flow and respiratory compensation. RESULTS: Sharpness of edges of the vessels on fast cine MR images was better than that on conventional cine MR images in 34 (57%) of 60 images. Inhomogeneous blood signal in aortic lumen due to motion artifacts was found in 2 (3%) of fast cine MR images and in 15 (25%) of conventional cine MR images. The contrast-to-noise ratios of fast cine MR images were significantly better than those of conventional cine MR images (26.4 +/- 9.1 vs. 18.5 +/- 10.1; p < 0.05) when the region of interest for noise was placed to include ghosting artifacts. CONCLUSION: Breath-hold cine MRI is a rapid technique that gives high quality images of thoracic aortic dissection and can provide a diagnosis in < 10 min of imaging time.

Arrhythmogenic ventricular aneurysms unrelated to coronary artery disease.

Malignant ventricular tachycardia occurs most frequently in patients with coronary artery disease who have had a previous myocardial infarction and in whom a ventricular aneurysm subsequently develops in the scarred section of myocardium. Ventricular tachycardia in the presence of normal coronary arteries and a left ventricular aneurysm is unusual and can be refractory to medical therapy. We retrospectively reviewed our experience of 10 patients treated at our institution from 1983 to 1993. Age ranged from 22 to 76 years, and all patients presented with sustained ventricular tachycardia. All patients underwent complete electrophysiologic testing. Cardiac catheterization was performed in 9 patients, and each had normal coronary artery anatomy without evidence of significant fixed lesions. A left ventricular aneurysm, diagnosed by either echocardiography, thoracic cine computed tomography or magnetic resonance imaging, or ventricular angiography was present in all patients. Ventricular tachycardia could not be suppressed pharmacologically in 7 of 10 patients using multiple agents including procainamide, quinidine, flecanide, tocainide, propaferone, and amiodarone. Six patients were treated surgically by intraoperative electrophysiologic mapping, endocardial resection of foci, and left ventricular aneurysmectomy. An implantable cardiac defibrillation device was implanted in 2 patients. One patient died on the second postoperative day after simultaneous mapping -guided aneurysmectomy and implantable cardioverter defibrillator placement. There was one late postoperative death. All other surgically treated patients had postoperative electrophysiologic studies demonstrating no inducible ventricular tachycardia, and these patients remain without antiarrhythmic therapy in follow-up extending from 29 to 86 months (mean, 56 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship of the proinflammatory cytokines to myocardial ischemia and dysfunction after uncomplicated coronary revascularization.

The proinflammatory cytokines have been implicated in mediating myocardial dysfunction associated with myocardial infarction, severe congestive heart failure, and sepsis. We tested the hypothesis that cytokine levels are elevated after uncomplicated coronary artery bypass grafting and associated with episodes of postoperative myocardial ischemia and dysfunction. Coronary artery bypass grafting was performed under general anesthesia with moderate systemic hypothermia and cold-blood potassium cardioplegic solution. Tumor necrosis factor-alpha and interleukin-6 levels were determined by bioassays, and interleukin-8 levels were measured by a sandwich enzyme-linked immunosorbent assay. Myocardial function and ischemic episodes were assessed by intraoperative transesophageal echocardiography and perioperative 12-channel Holter monitoring. A total of 22 patients were studied, with no deaths or complications. Arterial tumor necrosis factor-alpha rose in a bimodal distribution, peaking at 2 and 18 to 24 hours after the operation (at 20.2 +/- 6.4 pg/ml, [mean +/- standard error of the mean]) and 5.8 +/- 1.6 pg/ml, respectively; before cardiopulmonary bypass: 0.90 +/- 0.20 pg/ml, p < 0.001 for both peaks) then progressively declined to levels before bypass. Arterial interleukin-6 was maximally elevated immediately on termination of cardiopulmonary bypass and peaked again 12 to 18 hours after cardiopulmonary bypass (at 7520 +/- 2439 pg/ml and 6216 +/- 1928 pg/ml, respectively; before bypass: 746 +/- 187 pg/ml, p < 0.0001 for both peaks). Arterial interleukin-8 levels were more variable but followed a similar pattern, peaking in the early period after cardiopulmonary bypass and again at 16 to 18 hours after the operation (at 4110 +/- 1403 pg/ml and 1760 +/- 1145 pg/ml, respectively; before bypass: 461 +/- 158, p < 0.05 for both peaks). By multivariate analysis, the aortic crossclamp time was independently predictive of postoperative cytokine levels. Left ventricular wall motion abnormalities were associated with both interleukin-6 and interleukin-8 levels, worsening scores being associated with increasing levels (for interleukin-6, p = 0.003; for interleukin-8, p = 0.05). Postoperative myocardial ischemic episodes were associated with interleukin-6 levels, six of seven (85%) patients with episodes of myocardial ischemia after a peak in interleukin-6 concentrations (p < 0.01). We conclude that proinflammatory cytokines are elevated after uncomplicated coronary revascularization and may contribute to postoperative myocardial ischemia and segmental wall motion abnormalities.

Balloon aortic valvuloplasty as a bridge to aortic valve replacement in critically ill patients.

This report highlights our experience in 5 patients with severe aortic stenosis and multiple organ failure undergoing balloon aortic valvuloplasty as a bridge to conventional aortic valve replacement. Balloon aortic valvuloplasty successfully stabilized the condition of these patients, improved organ function, and decreased their baseline risk profile. Elective aortic valve replacement was then performed without complications. Short-term palliation with balloon aortic valvuloplasty should be considered as a bridge to aortic valve replacement in selected patients with critical aortic stenosis and multiple organ failure.

The safety and efficacy of ten percent pentastarch as a cardiopulmonary bypass priming solution. A randomized clinical trial.

Ten percent pentastarch is a low-molecular-weight hydroxyethyl starch with greater oncotic pressure and shorter intravascular persistence than 6% hetastarch. To evaluate its safety and efficacy as a component of cardiopulmonary bypass priming solution, we prospectively studied 90 patients undergoing coronary artery bypass grafting or valve replacement necessitating cardiopulmonary bypass (bubble oxygenator and moderate systemic hypothermia). Sixty patients were randomized to receive 75 gm of either 10% pentastarch (group P) or 25% albumin (group A), and 30 patients received lactated Ringer's solution alone (group C). Intravascular colloid osmotic pressure during cardiopulmonary bypass was highest with either of the colloid primes (15-minute measurement: group P, 15.7 +/- 2.2 mm Hg (mean +/- standard deviation); group A, 15.2 +/- 2.0 mm Hg; group C, 11.3 +/- 1.7 mm Hg; p less than 0.05, groups P and A compared with group C). This was associated with a lower volume requirement during cardiopulmonary bypass to maintain the venous reservoir (group P, 333 +/- 318 ml; group A, 483 +/- 472 ml; group C, 1332 +/- 1013 ml; p less than 0.05, groups P and A compared with group C). Urine output during cardiopulmonary bypass was similar in each group. Net intraoperative fluid balance was lowest in the colloid groups (groups P and A, 5.7 +/- 1.4 L; group C, 6.9 +/- 1.3 L; p less than 0.05, groups P and A compared with group C). Cardiac index shortly after weaning from cardiopulmonary bypass was greatest in group P (group P, 3.2 +/- 0.9; group A, 2.8 +/- 0.8; group C, 2.7 +/- 0.6 dyne.sec.cm-5; p less than 0.05, group P compared with group C). Changes in alveolar-arterial oxygen gradients, shunt fraction, and effective compliance were similar in all groups. During cardiopulmonary bypass, pentastarch appeared to cause the greatest degree of hemodilution, as suggested by the lowest hemoglobin, factor VII and IX levels and platelet count. The activated partial thromboplastin time was significantly prolonged during and immediately after cardiopulmonary bypass in group P relative to groups A and C (p less than 0.05), although there were no significant differences in the activated clotting time before cardiopulmonary bypass, during cardiopulmonary bypass, or after heparin neutralization. As well, clinical indices of hemostasis, including mediastinal drainage, red cell, platelet, and fresh frozen plasma requirements, and reoperation for excessive postoperative bleeding, were similar. We conclude that pentastarch, when used in cardiopulmonary bypass prime, is as safe as either albumin or Ringer's solution alone.(ABSTRACT TRUNCATED AT 400 WORDS)

Coronary artery calcifications: significance of incidental detection on CT scans.

A scoring system was devised for the assessment of coronary artery calcifications apparent on computed tomographic (CT) scans, with width and length used to assess severity. The degree of calcification was compared with the presence of stenoses of 70% or greater at cardiac catheterization in 46 patients who underwent both studies. Although many significantly stenosed vessels showed no calcification, heavy calcifications had a high positive predictive value for significant disease. In a separate branch of the study, the perioperative cardiac morbidity and mortality were compared in 30 age- and sex-matched pairs of patients undergoing thoracotomy who did and did not have coronary calcifications on CT scans obtained before surgery. Patients with calcifications had a higher frequency of cardiac complications, including arrhythmias, ischemia, hypotension, myocardial infarction, and death.

A randomized clinical trial of 10% pentastarch (low molecular weight hydroxyethyl starch) versus 5% albumin for plasma volume expansion after cardiac operations.

Pentastarch is a hydroxyethyl starch similar to hetastarch, but with a lower average molecular weight (264,000 versus 450,000) and fewer hydroxyethyl groups (molar substitution ratio = 0.45 versus 0.70). These characteristics result in enhanced enzymatic hydrolysis, faster renal elimination (initial intravascular half-life = 2.5 versus 25.5 hours), and less effect on coagulation. We report on a randomized clinical trial comparing the clinical efficacy and safety of 10% pentastarch (group P) for plasma volume expansion after cardiac operations with that of 5% serum albumin (group A). During the first 24 hours after arrival of the patient in the intensive care unit, colloid was infused to maintain a cardiac index of 2.0 L/m2 or more and a mean arterial pressure within 10% of the preinduction value. Group P (n = 50) received 1706 +/- 393 ml of colloid (mean +/- standard deviation) during this period, and group A (n = 44), 1794 +/- 341 ml (p = no significant difference). Hemodynamic responses to infusion were similar for both groups, although in group P a greater increase in both cardiac index (0.5 +/- 0.5 versus 0.3 +/- 0.5 L/min/m2 in group A, p less than 0.01) and left ventricular stroke work index (10.8 +/- 8.0 versus 5.8 +/- 6.0 gm-m/m2, p less than 0.01) was observed during infusion of the first 500 ml. There were no significant differences in any of the measured respiratory parameters (alveolar-arterial oxygen gradient, estimated shunt fraction, and effective pulmonary compliance). Hemodilution with colloid significantly reduced serum protein levels in group P by 24 hours postoperatively (4.0 +/- 0.6 versus 5.0 +/- 0.7 gm/dl in group A, p less than 0.05), although mean serum colloid osmotic pressure was similar (15.4 +/- 2.6 [P] versus 15.5 +/- 2.7 mmHg [A], p = no significant difference). There were no significant between-group differences in prothrombin time, activated partial thromboplastin time, platelet count, bleeding time, or coagulation factors (fibrinogen, V, VII, VIII, or IX) on postoperative days 1 and 7. Perioperative fluid balance, weight change, chest tube output, red blood, platelet, or fresh frozen plasma usage, reexploration for bleeding, and clinical outcome were also similar. These findings indicate that pentastarch is as safe and effective s 5% albumin for plasma volume expansion after cardiac operations with no apparent adverse effects on coagulation. If commercially available at a lower cost than albumin, it would appear to be a reasonable first choice for colloid therapy in this setting.

The Mustard procedure in infants (less than 100 days of age). Ten-year follow-up.

Surgical treatment of transposition of the great arteries and intact ventricular septum has changed markedly in the past 10 years. However, long-term follow-up on new approaches is not available. In a unique group of patients, operated on in the first 100 days of life with the Mustard procedure, such follow-up is available, and the results of these true infant repairs represent a benchmark against which subsequent techniques applied to infants should be compared. During the period of 1975 to 1980, 36 infants, less than 100 days of age, who had transposition of the great arteries and intact ventricular septum, underwent Mustard repair at the University of California, San Francisco. Ages ranged from 4 to 98 days (mean 46 days) and weights from 2.3 to 6.6 kg (mean 3.5 kg). There were no early deaths, and late follow-up was available from 8 to 13 years (mean 10 years). The late survival rate was 97% (mean 10 years). There was a 62% rhythm disturbance-free survival rate, 89% reoperation-free survival rate, and 91% pacemaker-free survival rate. Echocardiographic evaluation revealed obstruction of the superior vena cava in eight patients, tricuspid insufficiency in four, right ventricular dysfunction in two, and left ventricular outflow tract obstruction in three. The Mustard procedure, performed in the first 100 days of life, results in a high rate of survival (early 100% and late 97%, at a mean of 10 years) and a low incidence of late complications against which other techniques of infant repair should be compared.

Circulatory dynamics during surface-induced hypothermia under halothane-ether azeotrope anesthesia.

Circulatory dynamics during surface- induced deep hypothermia using the halothane-diethyl ether azeotrope in 100% oxygen (O2) without circulatory arrest and 95% O2 and 5% carbon dioxide (CO2) with and without 60 minutes of arrest were evaluated in 15 adult mongrel dogs. Mean arterial pressure was lower in animals given 5% CO2 than in animals given 100% O2 during cooling. Cardiac output in the 5% CO2 groups increased until 30 degrees C cooling and then gradually decreased to 29% of control at 20 degrees C. Cardiac output in the 100% O2 group progressively decreased to 16% of control at 20 degrees C cooling and was 51 to 77% of the output in the 5% CO2 animals at comparable temperatures throughout the hypothermia procedure. The differences in cardiac output were attributed primarily to changes in stroke volume since heart rates were not significantly different. These changes were probably secondary to differences in systemic vascular resistance, which had increased sixfold in the animals given 100% O2 and had only doubled in the 5% CO2 groups at 20 degrees C during cooling. Hemodynamic variables in animals given 5% CO2 did not reveal significant differences in arrested versus nonarrested animals during early rewarming. However, with further warming, cardiac output, stroke volume, left ventricular stroke work, and mean pulmonary arterial and pulmonary artery wedge pressures were lower, and systemic and pulmonary vascular resistances were higher in the arrest group. We conclude that the improved results with halothane-diethyl ether azeotrope in 95% O2 and 5% CO2 during surface hypothermia are due to a greater cardiac output and reduced peripheral vascular resistance.

Determination of cardiac output by thermodilution during hypothermia.

The thermodilution method for estimating cardiac output was compared with the electromagnetic flowmeter technique in 10 mongrel dogs at normothermia and during surface-induced deep hypothermia. Thermodilution curves obtained during cooling or rewarming must be corrected for the baseline drift caused by changing core temperature. At normothermia, the correlation coefficient between the two methods was 0.96 and the reproducibility of the thermodilution technique was 5 percent. Comparable correlation was present during hypothermia. Curves corrected for baseline drift resulted in significantly different output values from those derived from uncorrected curves (p < 0.05). The thermodilution method is valid at low body temperatures. Clinical confirmation of these results, particularly during open heart surgery in infants, is warranted.