Report of a case of gross thymic hyperplasia in a child.

A large thoracic mass and a mediastinal lymph node were excised from an infant with a peripheral blood and bone marrow lymphocytosis. The 224-mass was composed of histologically normal thymus, and the lymph node architecture was partially effaced. Hypogammaglobulinemia was detected two years after thymectomy. The enormous thumus in this case fits the classic gross pathologic definition of hyperplasia. The possibility of associated thymic hyperfunction in this case is discussed.

Effect of cardiopulmonary bypass and global ischemia on human and canine left ventricular mass: evidence for interspecies differences.

Previous studies in dogs suggest that global ischemia with cardiopulmonary bypass causes increased left ventricular (LV) mass and water content. To investigate effects in humans, we developed a simplified method for mass determination by intraoperative two-dimensional echocardiography. LV mass was measured as echocardiographic short-axis myocardial area. This was validated by linear regression versus postmortem LV mass in 10 dogs (r = 0.89) and versus single-plane angiography in 18 patients (r = 0.73). According to this method, there was no change in LV mass (209 gm versus 208 gm; NS) at constant preload in 20 patients during routine operations (eight coronary revascularizations, 10 aortic valve replacements, and two mitral valve replacements). The same method used in 10 dogs after 2 hours of bypass, 60 minutes of normothermic global ischemia, and reperfusion revealed an LV mass increase from 113 +/- 13 gm (SE) to 150 +/- 16 gm (p less than 0.01) at matched preload. In addition, in 14 dogs after 2 hours of bypass alone, LV mass was unchanged (98 +/- 5 gm versus 101 +/- 5 gm; NS) at matched preload. Data recently derived from a separate study in our laboratory revealed a statistically significant increase in canine LV mass when conditions of human cardiopulmonary bypass and cardioplegic arrest were reproduced. We conclude that uncomplicated cardiac operations in humans do not alter LV mass. This supports the safety of crystalloid cardioplegia in humans. While present evidence is not conclusive, it appears that the threshold for edema formation after ischemic injury may be higher in humans than it is in dogs. The clinical relevance of studies of cardioplegia in edematous dog hearts thus deserves careful scrutiny.

Transperitoneal solute movement in children.

The transperitoneal movement of solute in children was examined by means of a theoretical consideration of the peritoneal clearance formula and by the performance of peritoneal solute diffusion curves and measurement of peritoneal clearances of multiple solutes. Theoretical considerations led to the conclusion that when dialysis mechanics are held constant, peritoneal clearances scaled for weight are similar in individuals of widely varying weight when the volume of infused dialysate is also scaled for weight if peritoneal permeability and surface area are constant. In one group of studies, solute diffusion curves and weight-scaled peritoneal clearances of urea, phosphate, creatinine, and urate were similar in 3 children ages 4 to 18 months compared to 4 children ages 2.5 to 18.5 years. In a second group of studies, weight-scaled peritoneal clearances of inulin but not urea were shown to be marginally lower in 4 children who had been dialyzed longer than 6 months compared with 4 children dialyzed less than 1 month. Hypertonic glucose dialysis in these children was shown to enhance urea clearance but not that of inulin. It is concluded that comparative studies of peritoneal clearances can characterize the transperitoneal movement of solute in children of widely varying body size. Such studies are of greatest value when systematically performed and similar ratios of dialysate volumes to body pools of solute are used.

Effects of simulated clinical cardiopulmonary bypass and cardioplegia on mass of the canine left ventricle.

Myocardial edema is a well-documented response to ischemia and reperfusion in dogs and can be detected as an increase in left ventricular (LV) mass measured echocardiographically. Investigation in human beings has failed to demonstrate similar increases in LV mass after routine cardiac operations. However, direct comparison of these observations is not possible, because dogs have not been studied under conditions of cardiopulmonary bypass (CPB) and global ischemia that rigorously reproduce those of a clinical operation. Accordingly, clinical CPB and global ischemia were simulated in 8 adult dogs. Multisection two-dimensional echocardiograms and a computerized light pen were used to calculate LV volume and mass. The data were analyzed during four periods: before CPB; CPB before cross-clamping; CPB after cross-clamping, and after CPB. Echocardiographic LV mass increased significantly from 89.5 +/- 7.4 gm (before CPB) to 94.6 +/- 8.5 gm (CPB before cross-clamping) (p less than 0.05) and from 94.6 +/- 8.5 gm to 100.4 +/- 8.1 gm (CPB after cross-clamping) (p less than 0.05). Overall, mass increased 13.9% (p less than 0.05). Mean wall thickness increased 0.08 cm (p less than 0.05) overall and correlated with the increase in mass (r = 0.79). Postmortem mass correlated well with late echocardiographic mass (r = 0.95). Interobserver correlation of 98 separate mass determinations was high (r = 0.84) with a coefficient of variation of 10.5%. We conclude that canine LV mass increases significantly with CPB and global ischemia maintained within clinical standards and that human beings and dogs may differ in extent of edema during CPB.

Leiomyoma of the esophagus.

Esophageal leiomyoma, while rare, is the most common benign tumor of the esophagus. Nine cases from a large teaching hospital are reviewed with long-term follow-up. Steps in the diagnosis and management of this lesion are discussed.

Isolated regional perfusion; anaesthetic technique, monitoring and blood replacement.

Isolated regional perfusion for the treatment of malignant melanoma is an accepted method of treatment. No standard of anaesthetic practice has been established for those individuals. Perioperative records of patients undergoing isolated limb perfusion were studied to determine adequate blood replacement. Records were examined and compared for (1) age, (2) ASA physical status, (3) presence of associated disease, (4) anaesthetic technique, (5) the amount of blood and fluid replacement, (6) preoperative haemoglobin (hgb) and haematocrit (hct) and postoperative serial complete blood counts. Fifteen patients were studied (mean age 53 +/- 16 yrs). Mean blood and fluid replacement was: packed red blood cells; 2.28 +/- 0.82 units, 722 +/- 17 ml of 5 per cent albumin, 1747 +/- 21 ml crystalloid. There were twelve Physical Status Class I or II and three Class III patients. All patients received general anaesthesia. There was a statistically significant difference in the preoperative and postoperative values for haemoglobin and haematocrit (p less than 0.01) with no difference between the postoperative and discharge values. Adequate blood replacement was determined by the equation: (Formula: see text) Extensive invasive monitoring is not routinely required for adequate blood replacement or the detection of leaks between the systemic and isolated circulation.