The Science Journal of the American Association for Respiratory Care

1996 OPEN FORUM Abstracts

REDUCTION IN NEURAL RESPIRATORY DRIVE TO REDUCE VENTILATOR WEANING FAILURES USING BIOFEEDBACK

JE Holliday PhD, R Haake DO, M Range RRT. St Louis Regional Medical Center, St Louis MO.

We previously showed that biofeedback reduced weaning failures and time on the ventilator by 12 days (Am Rev Respir Dis 1990;141:121-140). We hypothesized that the underlying mechanism related to the effects of biofeedback was the reduction of high neural respiratory drive (P 100> 4.5 cm H_{2}O). A biofeedback instrument, "Computerized Diaphragmatic Breathing Retraining (CDBR)" (RFb Technologies, Deerfield Beach FL) was used to test the hypothesis. In order to determine if biofeedback could reduce neural respiratory drive, we studied 9 [5 males & 4 females with mean age 56.22 ± 3.38 (mean ± SE) yrs] hard-to-wean ventilator patients (on ventilator longer than 7 days) who could respond to verbal commands, 20 minutes of T-tube with O_{2} saturation of at least 90%, and be off all sedative type drugs for 4 hours. Patients rebreathed 7% CO_{2}/93% O_{2} for 2.5 min of baseline & 2.5 min of CDBR biofeedback. For the CDBR session compared to baseline there was a significant shift to the right in the end-tidal CO_{2} (PETCO_{2}) response curve. At maximum PETCO_{2} (70 mm Hg) the reduction in P100 = -2.904 ± 3.05 cm H_{2}O p < 0.01, EEG = -9.3 ± 3.55 c/s p < 0.05, minute ventilation (Vi) = -2.15 ± 2.99 L/min. p < 0.05, mean inspiratory flow (Vt/Ti) = -102.8 ± 99.5 p < 0.05 mL/s & respiration rate (RR) = -1.7 ± 1.44 br/min. p < 0.05. The results showed that CDBR feedback significantly reduced neural respiratory drive. To study reduction in neural respiratory drive during weaning, 6 internal medicine ventilator patients were selected over a period of one year with P100 > 4.5 cm H_{2}O, who were willing to sign the informed consent & had failed their initial weaning trial (could not tolerate T-tube longer than 15 min after 24.8 ± 1.04 mean ventilator days) because of high RR (mean RR = 40br/min) reflecting their high mean P100 = 7.15 ± 1.02. They were then given between one (3 Pts) and three 30 min CDBR sessions over a period of 1-2 days. At the end of CDBR feedback the mean P100 was 4.28 ± 1.04 cm H_{2}O, which was a significant reduction (p < 0.01), the mean RR = 32 br/min & no failed weaning trials resulting in 1.91 ± 0.49 mean days from start of CDBR till extubation. The above results support the hypothesis that biofeedback does reduce neural respiratory drive & appears to reduce weaning failures.

Reference: OF-96-030

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