Closed-Chest Cardiopulmonary Bypass and Cardioplegia: Basis for Less Invasive Cardiac Surgery

Background. We developed a method of closed-chest cardiopulmonary bypass to arrest and protect the heart with cardioplegic solution. This method was used in 54 dogs and the results were retrospectively analyzed.

Methods. Bypass cannulas were placed in the right femoral vessels. A balloon occlusion catheter was passed via the left femoral artery and positioned in the ascending aorta. A pulmonary artery vent was placed via the jugular vein. In 17 of the dogs retrograde cardioplegia was provided with a percutaneous coronary sinus catheter.

Results. Cardiopulmonary bypass time was 111 ± 27 minutes (mean ± standard deviation) and cardiac arrest time was 66 ± 21 minutes. Preoperative cardiac outputs were 2.9 ± 0.70 L/min and postoperative outputs were 2.9 ± 0.65 L/min (p = not significant). Twenty-one-French and 23F femoral arterial cannulas that allowed coaxial placement of the ascending aortic balloon catheter were tested in 3 male calves. Line pressures were higher, but not clinically limiting, with the balloon catheter placed coaxially.

Conclusions. Adequate cardiopulmonary bypass and cardioplegia can be achieved in the dog without opening the chest, facilitating less invasive cardiac operations. A human clinical trial is in progress.     

Nephrectomy during operative management of retroperitoneal sarcoma

Background: Complete resection of a retroperitoneal sarcoma often requires removal of adjacent organs. In this study we evaluated the role of nephrectomy during operation for retroperitoneal sarcoma. Methods: Between July 1982 and July 1995, 75 of the 371 (20%) patients who underwent resection of retroperitoneal sarcoma at MSKCC underwent concommitant nephrectomy. Data concerning the reasons for nephrectomy, degree of sarcomatous renal involvement, and survival were retrospectively analyzed. Results: Fifty-four patients (72%) underwent nephrectomy during the initial resection, and 21 (28%) during a resection of a recurrent or persistent tumor. The most common reason for nephrectomy was total encasement by sarcoma (n=40; 53%), followed by dense adherence of the tumor to the kidney (n=21; 28%), and the direct invasion of the kidney by tumor (n=2; 3%). Pathology demonstrated an absence of kidney invasion in the majority of cases (55 of 75; 73%). Renal capsular invasion was present in 11 of 75 (15%), renal parenchymal invasion in 7 of 75 (9%), and renal vein invasion in 2 of 75 (3%) of cases. There were no significant differences in survival based on degree of sarcoma involvement of the kidney, tumor grade, or whether the resection was for primary or recurrent disease. The 53 patients who underwent a complete gross resection of all tumor had a significantly improved long-term survival compared to the 20 patients who did not (50% versus 20% DFS at 5 years, respectively; p<0.001). Conclusions: Decisions for concomitant nephrectomy during resection of retroperitoneal sarcoma should be based on whether this maneuver will provide a complete resection of all gross tumor, in which case the long-term disease-free survival of 50% is comparable to the reported 5-year survival of all patients with retroperitoneal sarcoma who are completely resected. Presented at the 49th Annual Cancer Symposium of the Society of Surgical Oncology, Atlanta, Georgia, March 21–24, 1996.     

Intravenous feeding with medium chain triglycerides. Effect on blood gases and the complement system in critically ill patients

Critically ill patients are usually in a catabolic state and may require total parenteral nutrition; this often includes lipid emulsions. Any adverse effects of constituents on pulmonary function, white cell function or the haemocoagulation system could have disastrous consequences in such patients. We have investigated the effects of a new intravenous lipid preparation containing medium chain triglycerides, which, in severely ill malnourished patients are theoretically a preferable energy source to conventional drug chain triglycerides. In a pilot study 17 critically ill patients whose lungs were artificially ventilated were given this lipid emulsion; no adverse effects were observed. Arterial oxygen and carbon dioxide tensions, ratio of inspired oxygen fractional concentration to arterial oxygen tension, platelet and white cell counts all remained constant and the complement system was not activated.     

Response of lower esophageal contractility to changing concentrations of halothane or isoflurane: A multicenter study

A multiple-center study was performed to determine the relationship between lower esophageal contractility, clinical signs, and anesthetic concentration as expressed by minimum alveolar concentration (MAC). One hundred four American Society of Anesthesiologists Class I through III patients were exposed to isoflurane (with and without nitrous oxide) or halothane in concentrations of 0.5, 1.0, and 1.5 MAC. Heart rate and systolic blood pressure were continuously monitored. Both the amplitude and frequency of spontaneous and provoked lower esophageal contractions were measured in situ by using a 24-F probe equipped with provoking and measuring balloons. Combined results demonstrated statistically significant correlations (P<0.001) between lower esophageal contractility and MAC. Spontaneous lower esophageal contractions decreased from 1.10±0.12 (SEM) contractions per minute (0.5 MAC) to 0.42±0.05 (1 MAC) to 0.18±0.05 (1.5 MAC). Provoked lower esophageal contractility values decreased from 45±4 mm Hg (0.5 MAC) to 29±3 (1 MAC) to 19±2 (1.5 MAC). Heart rate changes did not correlate with MAC, and systolic blood pressure correlated in only one of three centers. Intracenter and intercenter analyses failed to demonstrate a significant relationship between lower esophageal contractility and heart rate or systolic blood pressure. No intracenter differences in either amplitude or frequency of lower esophageal contractions were observed, despite differences in volatile agents, induction techniques and agents, patient populations, and duration of anesthesia. Our studies indicate that lower esophageal contractility may be an indicator of anesthetic depth as reflected by MAC, but further studies are needed to quantify the effects of surgical stimulus, intravenous anesthetics, vasodilators, anticholinergics, calcium channel blockers, beta-adrenergic agonists, and the presence of a nasogastric tube.     

MR appearance of trigeminal and hypoglossal motor denervation.

PURPOSETo illustrate and describe the appearance of both long-standing and relatively recently occurring motor denervation of the hypoglossal nerve and of the third (mandibular) division of the trigeminal nerve (V3), with emphasis on findings particular to MR imaging.METHODSFindings from 11 patients with V3 denervation and from seven patients with hypoglossal denervation resulting from a variety of abnormalities were reviewed retrospectively. The motor denervation appearance and functional compromise of the affected musculature are described in terms of the chronicity of the denervation process.RESULTSThe appearance of V3 and hypoglossal motor denervation varies with the chronicity of the process. Long-standing denervation results in extensive fatty replacement and a decrease in the size of the affected musculature. Relatively recently occurring denervation results in abnormal contrast enhancement and edemalike signal changes in the denervated musculature. Fatty replacement was observed acutely in hypoglossal denervation but did not manifest until the subacute stage in V3 denervation. Increased volume of the denervated musculature may also accompany acute denervation signal changes.CONCLUSIONV3 and hypoglossal denervation have a variable appearance depending on the chronicity of the process. Recognition of MR imaging patterns of denervation may allow earlier diagnosis of a denervating lesion and may help to distinguish denervation from similar-appearing processes, such as infection or neoplasia.