Treatment of primary peritoneal mesothelioma by hyperthemic intraperitoneal chemotherapy.

Perfusion of the peritoneal cavity with chemotherapy agents under hyperthermic conditions has been utilized by several investigators in the treatment of intra-abdominal malignancies. Based on the concept that hyperthermia may potentiate the cytotoxic effects of chemotherapeutic agents, we embarked on a clinical trial of two-stage peritoneal chemotherapy for patients with primary peritoneal mesothelioma, a neoplasm unresponsive to traditional systemic chemotherapeutic regimens. In stage I, patients underwent surgical debulking of gross disease and placement of an intraperitoneal infusion catheter, through which intraperitoneal chemotherapy was administered for four months. Stage II consisted of debulking of residual tumor, placement of two transabdominal perfusion cannulae and administration of high-dose intraperitoneal chemotherapy at 40 degrees C using a simple, disposable perfusion circuit. Flow rates were maintained at 1 l/min, and inflow and outflow temperatures maintained at 42 and 40 degrees C, respectively. To date, three patients have undergone both phases of the protocol, with no perioperative complications related to either hyperthermia or end-organ toxicity. One patient died of progressive disease after three months, and two patients are alive and well. One patient developed a small bowel anastomotic leak three weeks after operation. In summary, intraoperative hyperthermic peritoneal chemotherapy may play a role in novel approaches to the treatment of peritoneal malignancies previously unresponsive to traditional chemotherapeutic regimens.

Laboratory evaluation of a low prime closed-circuit cardiopulmonary bypass system.

We have explored the potential advantages of a low prime closed-circuit cardiopulmonary bypass (CPB) system using a non-human primate model. Although manufacturers have reduced priming volumes in individual CPB components, the standard circuit volume remains high because of the tubing diameter and length necessary for gravity drainage. By replacing gravity drainage with the negative pressure generated by a centrifugal pump, we can realize significant tubing volume reduction. Closed-circuit bypass was conducted on 13 baboons ranging from 5-15 kg. The circuit consisted of a centrifugal pump, a hollow fiber oxygenator, and 1/4" arterial and venous tubing. The design of the circuit included the capacity to remove a limited amount of venous air. Circulatory arrest during deep hypothermia with volume displacement into a reservoir was also accomplished with this circuit. The potential benefits of this low prime closed-circuit bypass system include blood conservation and reduction in blood surface area contact. The future safe clinical use of this type of closed-circuit bypass for routine open heart surgery will depend upon the incorporation of a device in the venous line to remove air. This is the greatest threat to patient safety in a closed circuit system and its use for open chest surgery must wait until an efficient venous air elimination device is available.

Heparin washout in the pediatric Cell Saver bowl.

The possibility of residual heparin in washed red cells transfused to neonatal or pediatric cardiac patients following bypass prompted a measurement of heparin concentrations. Samples were taken during 10 adult and 10 neonatal and pediatric bypass cases. Sample A was from the bypass circuit, Sample B from the Haemonetics Cell Saver bowl inlet before washing, Sample C from the Cell Saver bowl outlet after washing, and Sample D from the patient ten minutes after protamine. Heparin concentrations were measured by a chromogenic assay using activated Factor X. There was no significant difference between the adult and pediatric groups in the levels of heparin concentration on bypass, pre-washing and post-washing, and in the patients following protamine. In the pediatric group, only .002% of the pre-washed heparin remained after washing. This extremely low level of heparin (.0027 units/ml) is only 0.34 units in a 125 ml pediatric unit of Cell Saver blood. Based on post bypass patient samples, this has no clinical significance. Therefore, the Cell Saver can be used safely with neonates and pediatric patients without concern regarding residual heparin when properly processed.