Higher flow rates improve heating during hyperthermic intraperitoneal chemoperfusion.

BACKGROUND/OBJECTIVES: Heated intraperitoneal chemotherapy (HIPEC) kills cancer cells via thermal injury and improved chemotherapeutic cytotoxicity. We hypothesize that higher HIPEC flow rates improve peritoneal heating and HIPEC efficacy. METHODS: (1) A HIPEC-model (30.8 L cooler with attached extracorporeal pump) was filled with 37°C water containing a suspended 1 L saline bag (SB) wrapped in a cooling sleeve, creating a constant heat sink. (2) HIPECs were performed in a swine model. Inflow, outflow, and peritoneal temperatures were monitored as flow rates varied. (3) Flow rates and temperatures during 20 HIPECs were reviewed. RESULTS: Higher flow rates decreased time required to increase water bath (WB) and SB temperature to 43°C. With a constant heat sink, the minimum flow rate required to reach 43°C in the WB was 1.75 L/min. Higher flow rates lead to greater temperature gradients between the WB and SB. In the swine model, the minimum flow rate required to reach 43°C outflow was 2.5-3.0 L/min. Higher flows led to more rapid heating of the peritoneum and greater peritoneal/outflow temperature gradients. Increased flow during clinical HIPEC suggested improved peritoneal heating with lower average visceral temperatures. CONCLUSIONS: There is a minimum flow rate required to reach goal temperature during HIPEC. Flow rate is an important variable in achieving and maintaining goal temperatures during HIPEC.

Increased risk of mucinous neoplasm of the appendix in adults undergoing interval appendectomy.

IMPORTANCE: The role of interval appendectomy after conservative management of perforated appendicitis remains controversial. Determining the etiology of perforated appendicitis is one reason to perform interval appendectomies. OBJECTIVE: To determine whether adult patients undergoing interval appendectomy experience an increased rate of neoplasms. DESIGN: Retrospective study. SETTING: A single tertiary care institution. PARTICIPANTS: All patients 18 years or older who underwent appendectomy for presumed appendicitis from January 1, 2006, through December 31, 2010. EXPOSURES Appendectomy for presumed appendicitis. MAIN OUTCOMES AND MEASURES: Underlying neoplasm as the cause of presentation for presumed appendicitis. Demographic data, clinicopathologic characteristics, interval resection rate, and complication data were collected and analyzed. RESULTS: During the study period, 376 patients underwent appendectomies. Interval appendectomy was performed in 17 patients (4.5%). Neoplasms were identified in 14 patients (3.7%); 5 of those tumors occurred in patients who had undergone interval appendectomy (29.4%). Nine neoplasms were mucinous tumors (64.3%), including all neoplasms associated with interval appendectomies. The mean age of all patients with appendiceal tumors was 49 years (range, 35-74 years). CONCLUSIONS AND RELEVANCE: Mucinous neoplasms of the appendix were found in 5 of 17 patients (29.4%) undergoing interval appendectomy. Interval appendectomies should be considered in all adult patients, especially those 40 years or older, to determine the underlying cause of appendicitis. A multi-institutional study to determine the generalizability of these findings is warranted.