Unusual response to continuous positive pressure ventilation

1976 ◽  
Vol 2 (2) ◽  
pp. 75-76 ◽  
Author(s):  
Guillermo A. Raimondi ◽  
Alejandro C. Raimondi ◽  
María L. Marchissio
Keyword(s):  
Positive Pressure Ventilation ◽  
Positive Pressure ◽  
Continuous Positive Pressure

Combination of constant-flow and continuous positive-pressure ventilation in canine pulmonary edema

1989 ◽  
Vol 67 (2) ◽  
pp. 817-823 ◽  
Author(s):  
J. I. Sznajder ◽  
C. J. Becker ◽  
G. P. Crawford ◽  
L. D. Wood
Keyword(s):  
Pulmonary Edema ◽  
Positive Pressure Ventilation ◽  
Alveolar Ventilation ◽  
Positive Pressure ◽  
Constant Flow ◽  
Positive End Expiratory Pressure ◽  
Ventilatory Mode ◽  
Continuous Positive Pressure ◽  
Bronchoscopic Guidance ◽  
Normal Lungs

Constant-flow ventilation (CFV) maintains alveolar ventilation without tidal excursion in dogs with normal lungs, but this ventilatory mode requires high CFV and bronchoscopic guidance for effective subcarinal placement of two inflow catheters. We designed a circuit that combines CFV with continuous positive-pressure ventilation (CPPV; CFV-CPPV), which negates the need for bronchoscopic positioning of CFV cannula, and tested this system in seven dogs having oleic acid-induced pulmonary edema. Addition of positive end-expiratory pressure (PEEP, 10 cmH2O) reduced venous admixture from 44 +/- 17 to 10.4 +/- 5.4% and kept arterial CO2 tension (PaCO2) normal. With the innovative CFV-CPPV circuit at the same PEEP and respiratory rate (RR), we were able to reduce tidal volume (VT) from 437 +/- 28 to 184 +/- 18 ml (P less than 0.001) and elastic end-inspiratory pressures (PEI) from 25.6 +/- 4.6 to 17.7 +/- 2.8 cmH2O (P less than 0.001) without adverse effects on cardiac output or pulmonary exchange of O2 or CO2; indeed, PaCO2 remained at 35 +/- 4 Torr even though CFV was delivered above the carina and at lower (1.6 l.kg-1.min-1) flows than usually required to maintain eucapnia during CFV alone. At the same PEEP and RR, reduction of VT in the CPPV mode without CFV resulted in CO2 retention (PaCO2 59 +/- 8 Torr). We conclude that CFV-CPPV allows CFV to effectively mix alveolar and dead spaces by a small bulk flow bypassing the zone of increased resistance to gas mixing, thereby allowing reduction of the CFV rate, VT, and PEI for adequate gas exchange.

scholarly journals Redistribution of Alveolar Pressure During Continuous Positive Pressure Ventilation with End Inspiratorg Pause

1996 ◽  
Vol 3 (3) ◽  
pp. 203-208
Author(s):  
Shun Satoh ◽  
Takashi Horinouchi ◽  
Atsushi Kaise ◽  
Shu Matsukawa ◽  
Yasuhiko Hashimoto ◽  
...  
Keyword(s):  
Positive Pressure Ventilation ◽  
Positive Pressure ◽  
Alveolar Pressure ◽  
Continuous Positive Pressure

Effects of continuous positive-pressure ventilation in experimental pulmonary edema

1976 ◽  
Vol 40 (4) ◽  
pp. 568-574 ◽  
Author(s):  
P. C. Hopewell ◽  
J. F. Murray
Keyword(s):  
Pulmonary Edema ◽  
Left Atrial ◽  
Positive Pressure Ventilation ◽  
Colloid Osmotic Pressure ◽  
Intermittent Positive Pressure Ventilation ◽  
Water Volume ◽  
Positive Pressure ◽  
Positive End Expiratory Pressure ◽  
Continuous Positive Pressure ◽  
Double Isotope

We compared the effects of continuous positive-pressure ventilation (CPPV), using 10 cmH2O positive end-expiratory pressure (PEEP), with intermittent positive-pressure ventilation (IPPV), on pulmonary extravascular water volume (PEWV) and lung function in dogs with pulmonary edema caused by elevated left atrial pressure and decreased colloid osmotic pressure. The PEWV was measured by gravimetric and double-isotope indicator dilution methods. Animals with high (22–33 mmHg), moderately elevated (12–20 mmHg), and normal (3–11 mmHg) left atrial pressures (Pla) were studied. The PEWV by both methods was significantly increased in the high and moderate Pla groups, the former greater than the latter (P less than 0.05). There was no difference in the PEWV between animals receiving CPPV and those receiving IPPV in both the high and moderately elevated Pla groups. However, in animals with high Pla, the Pao2 was significantly better maintained and the inflation pressure required to deliver a tidal volume of 12 ml/kg was significantly less with the use of CPPV than with IPPV. We conclude that in pulmonary edema associated with high Pla, PEEP does not reduce PEWV but does improve pulmonary function.

Cricothyroid muscle activity during sleep in normal adult humans

1994 ◽  
Vol 76 (6) ◽  
pp. 2326-2332 ◽  
Author(s):  
S. T. Kuna ◽  
J. S. Smickley ◽  
C. R. Vanoye ◽  
T. H. McMillan
Keyword(s):  
Eye Movement ◽  
Rem Sleep ◽  
Positive Pressure Ventilation ◽  
Nrem Sleep ◽  
Normal Adult ◽  
Positive Pressure ◽  
Rapid Eye Movement ◽  
Adult Humans ◽  
Inspiratory Activity ◽  
Continuous Positive Pressure

Previous investigators reported that cricothyroid (CT) muscle usually exhibits phasic inspiratory activity in normal adult humans during wakefulness. The purpose of this study was to determine respiratory-related CT activity in normal adult humans during sleep. Nighttime polysomnograms were performed in 16 subjects. Hooked-wire electrodes were percutaneously implanted in CT with 21-gauge needle-catheter unit that allowed artifact-free monopolar recordings during electrode placement. During wakefulness, CT was usually phasically active on inspiration, with tonic activity throughout the respiratory cycle. Phasic inspiratory activity was present throughout sleep in all subjects, even those without respiratory-related CT activity during wakefulness. Compared with non-rapid-eye-movement (NREM) sleep, phasic CT activity uniformly increased in rapid-eye-movement (REM) sleep. No differences were apparent in height of phasic CT activity between phasic and tonic REM sleep. Application of nasal continuous positive pressure in stage 3/4 NREM sleep was associated with a decrease in phasic CT activity. Passively induced hypocapnia with positive-pressure ventilation via a nose mask in stage 3/4 NREM sleep was associated with a disappearance of phasic CT activity. Cessation of positive-pressure ventilation under hypocapnic conditions frequently resulted in apnea. Phasic CT activity remained absent during apnea but reappeared coincident with or soon after resumption of spontaneous respiration. In summary, CT′s phasic inspiratory activity and respiratory-related response to various stimuli during sleep were very similar to those of posterior cricoarytenoid muscle, the principal vocal cord abductor.

Continuous positive-pressure ventilation does not alter ventricular pressure-volume relationship

1981 ◽  
Vol 240 (6) ◽  
pp. H821-H826 ◽  
Author(s):  
J. E. Fewell ◽  
D. R. Abendschein ◽  
C. J. Carlson ◽  
E. Rapaport ◽  
J. F. Murray
Keyword(s):  
Mechanical Properties ◽  
Positive Pressure Ventilation ◽  
Venous Return ◽  
Intermittent Positive Pressure Ventilation ◽  
Left Ventricular ◽  
Positive Pressure ◽  
Volume Relationship ◽  
Pressure Volume Relationship ◽  
The Right ◽  
Continuous Positive Pressure

To determine whether alterations in the mechanical properties (i.e., stiffening) of the right and left ventricles contribute to the decrease in right and left ventricular end-diastolic volumes during continuous positive-pressure ventilation (CPPV), we studied six dogs anesthetized with chloralose urethane and ventilated with a volume ventilator. We varied ventricular volumes by withdrawing or infusing blood. Pressure-volume curves, constructed by plotting transmural ventricular end-diastolic pressures against ventricular end-diastolic volumes, did not change during CPPV (12 cmH2O positive end-expiratory pressure) compared to intermittent positive-pressure ventilation (IPPV, 0 cmH2O end-expiratory pressure). We conclude that decreased ventricular end-diastolic volumes during CPPV result primarily from a decrease in venous return. Alterations in the mechanical properties of the ventricles do not play a significant role in this response.

Continuous Positive-Pressure Ventilation in Acute Respiratory Failure

1970 ◽  
Vol 283 (26) ◽  
pp. 1430-1436 ◽  
Author(s):  
Anil Kumar ◽  
Konrad J. Falke ◽  
Bennie Geffin ◽  
Carolyn F. Aldredge ◽  
Myron B. Laver ◽  
...  
Keyword(s):  
Respiratory Failure ◽  
Acute Respiratory Failure ◽  
Positive Pressure Ventilation ◽  
Positive Pressure ◽  
Continuous Positive Pressure
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