Effect of the initiation of noninvasive bi-level positive airway pressure on haemodynamic stability

Abstract

Noninvasive ventilation using noninvasive bilevel positive airway pressure (Bi-PAP) has been shown to be an effective means of improving oxygenation and respiratory status in patients with obstructive pulmonary disease (COPD) and acute congestive heart failure (CHF). However, it is uncertain what effects this positive airway pressure has on the haemodynamic condition of these patients. This study examines the acute changes in basic circulatory parameters with the initiation of Bi-PAP. Noninvasive measurements of the heart rate, systolic and diastolic arterial pressure, cardiac index, total peripheral resistance, ventricular ejection time, and total diastolic time were determined by impedance cardiography before and after the institution of Bi-PAP (pressures 15/5) in a group of healthy volunteers. In a collateral study, the same measurements were made in COPD patients in whom Bi-PAP was initiated for therapeutic reasons. Changes in the haemodynamic parameters were analysed using a paired t-test (p < 0.05). In the 12 healthy volunteers studied there were no significant differences in any of the haemodynamic parameters measured (average cardiac index: 2.75 +/- 0.78) over a period of 15 minutes after the placement of Bi-PAP. Similar results for most haemodynamic parameters were found in the 7 COPD patients with imminent respiratory failure (average respiratory rate 24.8 +/- 3.2) when Bi-PAP was utilized with the exception of significant but small increases in the cardiac index, stroke volume and oxygen saturation (p<0.05). While Bi-PAP is frequently used in the treatment of patients with acute respiratory failure, little is known about its effect on haemodynamics. This study suggests that the effects of the initiation of Bi-PAP on the general circulation and cardiac output may be of minor relevance.

Noninvasive Assisted Pressure-Controlled Ventilation: As Effective as Pressure Support Ventilation in Chronic Obstructive Pulmonary Disease?

“…In accordance with the results of several studies published previously [2,3,4,5,6,7,8,9,10,11,12, 16, 17], we observed significant improvements in breathing patterns after NIV. These improvements were probably due to the reduction in RR and increase in V T which led to an enhancement in alveolar ventilation and V E as reported in the study by Diaz et al [13].…”

“…We hypothesized that if we could use APCV for NIV and set the T insp to the maximum of 1 s, we probably would achieve a better patient-ventilator synchrony, leading to an effective CO 2 elimination despite mask leaks. On the other hand, the effect of IMV in producing deleterious changes in cardiac functions and hemodynamics was previously well established, but whether NIV (neither PSV nor APCV) similarly affects cardiac functions or not still remains controversial [12,13,14]. …”

Complications of non-invasive ventilation techniques: a comprehensive qualitative review of randomized trials

“…90 -96 In stable COPD patients, pressure-support ventilation (PSV) (PS of 10 -20 cm H 2 O over PEEP of 5 cm H 2 O) decreases CO without changing arterial AP or heart rate. 97 In COPD patients with severe hypercapnic ARF, PSV (i.e. PS of 12 cm H 2 O over PEEP 3 cm H 2 O) through a full face mask decreases CO by 10-13%.…”

Early emergency management of acute decompensated heart failure

“…The pressure provided by Bi-PAP to the alveoli was thought to reverse the pulmonary edema. More recent evidence suggests that this is a well tolerated intervention that improves hemodynamics in these patients [43,44]. More recent evidence suggests that this is a well tolerated intervention that improves hemodynamics in these patients [43,44].…”