THE EFFECTS OF POSTOPERATIVE FORCED-AIR REWARMING ON SUBCUTANEOUS TISSUE OXYGEN TENSION AND WOUND HEALING IN HYPOTHERMIC ABDOMINAL SURGICAL PATIENTS.
Contributors: University of California, San Francisco.
Published: 1994
Number of pages: 98
Subjects: Health Sciences, Nursing.; Health Sciences, Medicine and Surgery.
Description: Perioperative hypothermia is common because of cold exposure and anesthesia-inhibited thermoregulation. Hypothermia decreases subcutaneous tissue oxygen tension (PsqO$\sb2).$ Low PsqO$\sb2$ correlates with a high risk of wound infection and impaired healing. It was hypothesized that, compared to passive rewarming with blankets (standard care), hypothermic postoperative abdominal surgical patients actively rewarmed with forced-air would have significantly greater PsqO$\sb2,$ subcutaneous temperature (sqT), skin-surface temperatures, thermal comfort, and collagen deposition, despite comparable core temperatures.

Patients with intraoperative core temperature $\le$35$\sp\circ$C were randomized to standard care (C, n = 7) or forced-air wanner (FA, n = 10). PsqO$\sb2$ was measured in a silicon tube implanted subcutaneously in the arm. Measurements were made with the patients breathing 60% inspired oxygen for six hours after arrival in the post anesthesia care unit, and on postoperative day (POD) 1 and 2. Collagen deposition was measured by subcutaneously placed expanded polytetrafluoroethylene (ePTFE) implants removed on POD 7.

Mean $\pm$ SD PsqO$\sb2$ (mmHg) was greater in FA vs C at 2h (71 $\pm$ 41 vs 47 $\pm$ 20), 5h (85 $\pm$ 25 vs 59 $\pm$ 35), and 6h (93 $\pm$ 36 vs 65 $\pm$ 41), although this did not reach statistical significance. PsqO$\sb2$ was significantly greater (p = 0.009) in FA vs C on POD 1 (121 $\pm$ 37 vs 55 $\pm$ 23), but not on POD 2 (93 $\pm$ 40 vs 72 $\pm$ 34). Core temperatures were comparable. Skin-surface temperatures, sqT, and thermal comfort scores were significantly greater for FA vs C. Collagen deposition at POD 7 was higher in FA, but did not reach significance (FA 4.63 $\pm$ 4.8 vs C 2.57 $\pm$ 1.2, mcg/cm).

Postoperative forced-air rewarming increases PsqO$\sb2,$ sqT, skin-surface temperatures and thermal comfort more rapidly, and to a greater extent, than standard care. PsqO$\sb2$ and sqT, which reflect wound perfusion, remained greater for at least 24 h after active rewarming ceased, implying a sustained treatment effect. High PsqO$\sb2$ protects against wound infection. Thus, rapid postoperative rewarming may improve clinical outcomes.
Notes: Source: Dissertation Abstracts International, Volume: 55-09, Section: B, page: 3825.

Thesis (D.N.S.)--UNIVERSITY OF CALIFORNIA, SAN FRANCISCO, 1994.

School code: 0034.