Cost-effectiveness and efficacy of an on-site homograft heart-valve bank.

OBJECTIVE: To compare the performance and cost-effectiveness of cryopreserved homograft cardiac valves prepared on site to valves prepared commercially. DESIGN: A review of all patients who received homograft heart valves between January 1990 and December 1993, with cost-effectiveness analysis. Follow-up ranged from 1 to 37 months (mean 12 months). SETTING: Tertiary-care adult and pediatric hospitals. PATIENTS: All consecutive patients receiving homograft heart valves in either the aortic or right ventricular outflow tract (RVOT) position since on-site preparation of cryopreserved cardiac valves began in 1990. Forty-three patients received 47 homograft valve replacements: 18 in the aortic position and 29 in the RVOT position. No patients were lost to follow-up. MAIN OUTCOME MEASURES: Valve function as assessed by patient survival, actuarial freedom from reoperation and Doppler echocardiographic assessment of transvalvar gradients and valvar insufficiency. Cost-effectiveness as assessed by a formal evaluation of on-site costs compared with current prices for commercially prepared valves. RESULTS: There were four operative deaths but no late deaths. Four valves were removed. Freedom from reoperation at 3 years was 100% for aortic valve replacement and 85% for RVOT reconstruction. Echocardiographic follow-up of 34 of the remaining 39 patients showed mild or no insufficiency in 24 valves, moderate insufficiency in 8 valves and severe, but not clinically significant, insufficiency in 2 valves. The cost of on-site preparation of the valves was $1363 compared with $5040 for the commercially prepared valves, a cost saving for the group of $172,819. CONCLUSION: On-site preparation is an effective method of preparing cryopreserved cardiac valves and permits significant cost savings.

A simplified protocol for banking bone from surgical donors requiring a 90-day quarantine and an HIV-1 antibody test.

The banking of femoral heads from patients who undergo total hip arthroplasty provides a valuable resource for orthopedic surgery. Quality assurance of the banked bone used in clinical procedures requires documented policies for screening, procuring, storing and distributing. Potential donors are screened at the time of donation for malignant disease, possible communicable disease, sepsis and high-risk life-styles. After negative culture results are confirmed and appropriate documentation has been completed, the bone is frozen at -70 degrees C. A quarantine period of 90 days follows. The donor is followed up 90 days or more postoperatively. At that time written consent is obtained for donation of the recovered tissue to the bone bank and for serology testing for human immunodeficiency virus (HIV-1) antibody, hepatitis B surface antigen (HBsAG), hepatitis B core antibody (HBcAb) and syphilis, and the donor is rescreened for contraindications. This protocol meets or exceeds all existing standards. The combination of obtaining consent and serology testing at 90 days streamlines the logistics of banking bone from surgical donors.

Respiratory drive during sudden cold water immersion.

Sudden decreases in cutaneous temperature induce an immediate ventilatory response, which has been termed the inspiratory or 'gasp' reflex. This respiratory response has been implicated as a contributing factor to cold water immersion drowning. In the present study, five subjects wearing either shorts or a variety of thermal protective apparel were immersed on separate occasions in 10 degrees C water. The observed peak mean skin temperature cooling rates (dTs/dt) for the different conditions varied from 6.9 +/- 2.1 degrees C/min for the shorts condition to 1.8 +/- 0.3 degrees C/min for a helicopter pilot suit made of cotton ventile material. During the immersion, recordings were made of respiratory drive, as indicated by the mouth occlusion pressure at 100 msec following the onset of inspiration (P0.1). The respiratory drive, an indicator of central inspiratory activity, correlated well with peak dTs/dt. The slope P0.1/(dTs/dt) was subject dependent and did not appear to be related to body composition. The substantial intersubject variability in the respiratory response is suggested to result from differences in the central integration of thermoafferent information. It is concluded that the inspiratory reflex is the result of cutaneous thermoreceptor activity.