Elsevier

Respiratory Medicine

Volume 96, Issue 8, August 2002, Pages 572-579
Respiratory Medicine

Regular Article
Normocapnia during nIPPV in chronic hypercapnic COPD reduces subsequent spontaneous PaCO2

https://doi.org/10.1053/rmed.2002.1326Get rights and content
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Abstract

Hypercapnia has been accepted during nasal intermittent positive pressure ventilation (nIPPV) and during subsequent spontaneous breathing in patients with chronic hypercapnic respiratory failure (HRF) due to COPD. We tested the hypothesis that nIPPV aimed at normalizing P aCO2 will reduce P aCO2 during subsequent spontaneous breathing. For that purpose 14 consecutive inpatients (age 61.4±9.9 years) with chronic HRF due to COPD were established on passive pressure-controlled nIPPV in a stepwise approach. Assisted ventilation with supplemental oxygen to reach normoxemia was started followed by passive ventilation with a stepwise increment in the inspiratory pressure and finally by a stepwise increase in the respiratory rate to establish normocapnia. Baseline pulmonary function parameters were: FEV1 0.97±0.43 l, P aCO2 59.5±8.4 mmHg, P aO2 49.9±7.8 mmHg, HCO3 35.6±5.2 mmol/l, pH 7.39±0.04. Normoxemia as well as normocapnia was thus established by decreasing P aCO2 by 19.5±7.0 mmHg during nIPPV within 8.8±3.8 days (P<0.001) (inspiratory pressure 29.8±3.8 mmHg, respiratory rate 22.9±1.9 BPM). Spontaneous P aCO2 measured 4 h after cessation of nIPPV decreased to 46.0±5.5 mmHg (P<0.001), and HCO3 decreased to 27.2±3.0 mmol/l (P<0.001). At 6 months of follow-up, 11 patients continued nIPPV with stable blood gases and with a decrease of P 0.1/P lmax from 9.4±4.3% to 5.9±2.0% (P<0.005). In conclusion, normalization of P aCO2 by passive nIPPV in patients with HRF due to COPD is possible and leads to a significant reduction of P aCO2 during subsequent spontaneous breathing and is associated with improved parameters of respiratory muscle function.

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Correspondence should be addressed to: Wolfram Windisch, Department of Pneumology, University Hospital Freiburg, Killianstraße 5, D- 79106 Freiburg, Germany. Fax: +49 761 270 3704; E-mail: [email protected]