title: Physiological changes during low- and high-intensity noninvasive ventilation.
abstract: In a physiological randomised cross-over study performed in stable hypercapnic chronic obstructive disease patients, we assessed the short-term effects of two settings of noninvasive ventilation. One setting was aimed at maximally reducing arterial carbon dioxide tension (P(a,CO(2))) (high-intensity (Hi) noninvasive positive pressure ventilation (NPPV)): mean ± SD 27.6 ± 2.1 cmH(2)O of inspiratory positive airway pressure, 4 ± 0 cmH(2)O of expiratory positive airway pressure and respiratory rate of 22 breaths · min(-1). The other was performed according to the usual parameters used in earlier studies (low-intensity (Li)-NPPV): 17.7 ± 1.6 cmH(2)O of inspiratory positive airway pressure, 4 ± 0 cmH(2)O of expiratory positive airway pressure and respiratory rate of 12 breaths · min(-1). Both modes of ventilation significantly improved gas exchange compared with spontaneous breathing (SB), but to a greater extent using Hi-NPPV (P(a,CO(2)) 59.3 ± 7.5, 55.2 ± 6.9 and 49.4 ± 7.8 mmHg for SB, Li-NPPV and Hi-NPPV, respectively). Similarly, Hi-NPPV induced a greater reduction in the pressure-time product of the diaphragm per minute from 323 ± 149 cmH(2)O · s · min(-1) during SB to 132 ± 139 cmH(2)O · s · min(-1) during Li-NPPV and 40 ± 69 cmH(2)O · s · min(-1) during Hi-NPPV, while in nine out of 15 patients, it completely abolished SB activity. Hi-NPPV also induced a marked reduction in cardiac output (CO) measured noninvasively with a Finometer PRO (Finapres Medical Systems BV, Amsterdam, the Netherlands) compared with Li-NPPV. We conclude that while Hi-NPPV is more effective than Li-NPPV in improving gas exchange and in reducing inspiratory effort, it induces a marked reduction in CO, which needs to be considered when Hi-NPPV is applied to patients with pre-existing cardiac disease.
authors: Dept of Pulmonology, Semmelweis University, Budapest, Hungary.
authors: J
authors: J
authors: Lukácsovits
authors: A
authors: A
authors: Carlucci
authors: N
authors: N
authors: Hill
authors: P
authors: P
authors: Ceriana
authors: L
authors: L
authors: Pisani
authors: A
authors: A
authors: Schreiber
authors: P
authors: P
authors: Pierucci
authors: G
authors: G
authors: Losonczy
authors: S
authors: S
authors: Nava
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002245:Carbon Dioxide / Q000097:blood; D018592:Cross-Over Studies; D004417:Dyspnea / Q000503:physiopathology / Q000628:therapy; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011175:Positive-Pressure Respiration / Q000009:adverse effects / Q000379:methods*; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000628:therapy*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D015656:Respiratory Mechanics / Q000502:physiology; D056152:Respiratory Rate / Q000502:physiology; D016896:Treatment Outcome
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen