Abstract:
:Studies of the hemodynamic effects of nasal continuous positive airway pressure (n-CPAP) in normal subjects have had conflicting results. The largest study (n = 19) found no effect of up to 15 cm H2O on heart rate (HR), cardiac stroke volume (SV), or cardiac index. We hypothesized that n-CPAP, by increasing intrathoracic pressure, should decrease SV and cardiac output (CO) in a dose-dependent fashion in normal subjects. We also hypothesized that mouth position, i.e., open or closed, could affect intrathoracic pressure and thus SV and CO. Six normal subjects were tested with four levels of CPAP (5, 10, 15, and 20 cm H2O) under three mask conditions-face mask and nasal mask with the mouth open (mo) or with the mouth closed (mc). Noninvasive pulsed Doppler measurements of SV and HR were made under each condition. N-CPAP (mc) and face mask CPAP (f-CPAP) resulted in significant dose-dependent decreases of SV-24 +/- 5 ml (21%) and 33 +/- 5 ml (28%), respectively--from baseline to 20 cm H2O (p < 0.05). HR were unchanged and CO significantly decreased with n-CPAP(mc) and with f-CPAP, 1.6 +/- 0.38 L/min (23%) and 2.29 +/- 0.54 L/min (31%), respectively, from baseline to 20 cm H2O (p < 0.05). Esophageal pressure measurements verified increasing intrathoracic pressure with increasing levels of f-CPAP and n-CPAP (mc) but not with n-CPAP (mo). In conclusion, n-CPAP (mc) and f-CPAP resulted in significant and similar dose-dependent decreases in SV and CO.
journal_name
Am J Respir Crit Care Medauthors
Montner PK,Greene ER,Murata GH,Stark DM,Timms M,Chick TWdoi
10.1164/ajrccm.149.6.8004320subject
Has Abstractpub_date
1994-06-01 00:00:00pages
1614-8issue
6eissn
1073-449Xissn
1535-4970journal_volume
149pub_type
临床试验,杂志文章,随机对照试验abstract::The nasal mucosal is the first site of contact with inhaled antigens. However, the nature of local immune responses and the role of nasal-associated lymphoid tissue (NALT) in those responses have rarely been studied. To characterize the cells involved in mucosally derived immune responses, NALT and Peyer's patch (PP) ...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.156.4.97-03017
更新日期:1997-10-01 00:00:00
abstract::To investigate whether the magnitude of blood flow contributes to ventilator-induced lung injury, 14 sets of isolated rabbit lungs were randomized for perfusion at either 300 (Group A: n = 7) or 900 ml/ min (Group B: n = 7) while ventilated with 30 cm H2O peak static pressure. Control lungs (Group C: n = 7) were venti...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
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更新日期:1998-06-01 00:00:00
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journal_title:American journal of respiratory and critical care medicine
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journal_title:American journal of respiratory and critical care medicine
pub_type: 临床试验,杂志文章,随机对照试验
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更新日期:1994-06-01 00:00:00
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journal_title:American journal of respiratory and critical care medicine
pub_type: 临床试验,杂志文章
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更新日期:1996-11-01 00:00:00
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更新日期:1998-01-01 00:00:00