scholarly journals The Effect of Sustained Positive Airway Pressure on Derived Cardiac Output in Children

1994 ◽  
Vol 22 (1) ◽  
pp. 30-34 ◽  
Author(s):  
J. B. Clough ◽  
A. W. Duncan ◽  
P. D. Sly

It is well established that the improvement in gas exchange that occurs with positive pressure ventilation may come at the expense of a decrease in cardiac output and oxygen delivery. Clinical observation suggests that children and infants may be more resistant than adults to the falls in cardiac output induced by positive airway pressure. The aims of this study were to quantify the effect of a sustained increase in intrathoracic pressure on cardiac output and stroke volume, and to determine whether this change is age-related. Twenty-eight children undergoing general anaesthesia were studied. Cardiac output was derived using pulsed wave Doppler techniques at four different levels of sustained positive airway pressure, and stroke volume was calculated. The relationship between airway pressure and both cardiac output and stroke volume was examined using a general linear model which included age as a continuous variable. Cardiac output decreased with increasing levels of sustained positive airway pressure (P=0.001). The fall in SV for a given airway pressure increased with increasing age (P=0.02). The mechanisms responsible for the increase of the magnitude of the fall in stroke volume with age remain to be elucidated.

2006 ◽  
Vol 15 (6) ◽  
pp. 580-593 ◽  
Author(s):  
Susan K. Frazier ◽  
Kathleen S. Stone ◽  
Debra Moser ◽  
Rebecca Schlanger ◽  
Carolyn Carle ◽  
...  

• Background Cardiac dysfunction can prevent successful discontinuation of mechanical ventilation. Critically ill patients may have undetected cardiac disease, and cardiac dysfunction can be produced or exacerbated by underlying pathophysiology. • Objective To describe and compare hemodynamic function and cardiac rhythm during baseline mechanical ventilation with function and rhythm during a trial of continuous positive airway pressure in medical intensive care patients. • Methods A convenience sample of 43 patients (53% men; mean age 51.1 years) who required mechanical ventilation were recruited for this pilot study. Cardiac output, stroke volume, arterial blood pressure, heart rate, cardiac rhythm, and plasma catecholamine levels were measured during mechanical ventilation and during a trial of continuous positive airway pressure. • Results One third of the patients had difficulty discontinuing mechanical ventilation. Successful patients had significantly increased cardiac output and stroke volume without changes in heart rate or arterial pressure during the trial of continuous positive airway pressure. Unsuccessful patients had no significant changes in cardiac output, stroke volume, or heart rate but had a significant increase in mean arterial pressure. The 2 groups of patients also had different patterns in ectopy. Concurrently, catecholamine concentrations decreased in the successful patients and significantly increased in the unsuccessful patients during the trial. • Conclusions Patterns of cardiac function and plasma catecholamine levels differed between patients who did or did not achieve spontaneous ventilation with a trial of continuous positive airway pressure. Cardiac function must be systematically considered before and during the return to spontaneous ventilation to optimize the likelihood of success.


Author(s):  
Bayane Sabsabi ◽  
Ava Harrison ◽  
Laura Banfield ◽  
Amit Mukerji

Objective The study aimed to systematically review and analyze the impact of nasal intermittent positive pressure ventilation (NIPPV) versus continuous positive airway pressure (CPAP) on apnea of prematurity (AOP) in preterm neonates. Study Design In this systematic review and meta-analysis, experimental studies enrolling preterm infants comparing NIPPV (synchronized, nonsynchronized, and bi-level) and CPAP (all types) were searched in multiple databases and screened for the assessment of AOP. Primary outcome was AOP frequency per hour (as defined by authors of included studies). Results Out of 4,980 articles identified, 18 studies were included with eight studies contributing to the primary outcome. All studies had a high risk of bias, with significant heterogeneity in definition and measurement of AOP. There was no difference in AOPs per hour between NIPPV versus CPAP (weighted mean difference = −0.19; 95% confidence interval [CI]: −0.76 to 0.37; eight studies, 456 patients). However, in a post hoc analysis evaluating the presence of any AOP (over varying time periods), the pooled odds ratio (OR) was lower with NIPPV (OR: 0.46; 95% CI: 0.32–0.67; 10 studies, 872 patients). Conclusion NIPPV was not associated with decrease in AOP frequency, although demonstrated lower odds of developing any AOP. However, definite recommendations cannot be made based on the quality of the published evidence. Key Points


2018 ◽  
Vol 37 (1) ◽  
pp. 24-32
Author(s):  
Jennifer M. Guay ◽  
Dru Carvi ◽  
Deborah A. Raines ◽  
Wendy A. Luce

Respiratory distress continues to be a major cause of neonatal morbidity. Current neonatal practice recommends the use of nasal continuous positive airway pressure (nCPAP) in the immediate resuscitation and continued support of neonates of all gestations with clinical manifestations of respiratory distress. Despite the many short- and long-term benefits of nCPAP, many neonatal care units have met resistance in its routine use. Although there have been numerous recent publications investigating the use and outcomes of various modes of nCPAP delivery, surfactant administration, mechanical ventilation, and other forms of noninvasive respiratory support (high-flow nasal cannula, nasal intermittent positive pressure ventilation), there has been a relative lack of publications addressing the practical bedside care of infants managed on nCPAP. Effective use of nCPAP requires a coordinated interprofessional team approach, ongoing assessment of the neonate, troubleshooting the nCPAP circuit, and parent education.


2008 ◽  
Vol 104 (5) ◽  
pp. 1402-1409 ◽  
Author(s):  
Kathy L. Ryan ◽  
William H. Cooke ◽  
Caroline A. Rickards ◽  
Keith G. Lurie ◽  
Victor A. Convertino

Inspiratory resistance induced by breathing through an impedance threshold device (ITD) reduces intrathoracic pressure and increases stroke volume (SV) in supine normovolemic humans. We hypothesized that breathing through an ITD would also be associated with a protection of SV and a subsequent increase in the tolerance to progressive central hypovolemia. Eight volunteers (5 men, 3 women) were instrumented to record ECG and beat-by-beat arterial pressure and SV (Finometer). Tolerance to progressive lower body negative pressure (LBNP) was assessed while subjects breathed against either 0 (sham ITD) or −7 cmH2O inspiratory resistance (active ITD); experiments were performed on separate days. Because the active ITD increased LBNP tolerance time from 2,014 ± 106 to 2,259 ± 138 s ( P = 0.006), data were analyzed (time and frequency domains) under both conditions at the time at which cardiovascular collapse occurred during the sham experiment to determine the mechanisms underlying this protective effect. At this time point, arterial blood pressure, SV, and cardiac output were higher ( P ≤ 0.005) when breathing on the active ITD rather than the sham ITD, whereas indirect indicators of autonomic activity (low- and high-frequency oscillations of the R-to-R interval) were not altered. ITD breathing did not alter the transfer function between systolic arterial pressure and R-to-R interval, indicating that integrated baroreflex sensitivity was similar between the two conditions. These data show that breathing against inspiratory resistance increases tolerance to progressive central hypovolemia by better maintaining SV, cardiac output, and arterial blood pressures via primarily mechanical rather than neural mechanisms.


2009 ◽  
Vol 4 (2) ◽  
pp. 41-45
Author(s):  
AKM Mosharraf Hossain ◽  
Mostofa Midhat Pasha

Obstructive sleep apnea (OSA) is the most common form of sleep-disordered breathing, affecting 5-15% of the population. It is characterized by intermittent episodes of partial or complete obstruction of the upper airway during sleep that disrupts normal ventilation and sleep architecture, and is typically associated with excessive daytime sleepiness, snoring, and witnessed apneas. Patients with obstructive sleep apnea present risk to the general public safety by causing 8-fold increase in vehicle accidents, and they may themselves also suffer from the physiologic consequences of OSA; these include hypertension, coronary artery disease, stroke, congestive heart failure, pulmonary hypertension, and cardiac arrhythmias. Of these possible cardiovascular consequences, the association between OSA and hypertension has been found to be the most convincing. Although the exact mechanism has not been understood, there is some evidence that OSA is associated with frequent apneas causing mechanical effects on intrathoracic pressure, cardiac function, and intermittent hypoxemia, which may in turn cause endothelial dysfunction and increase in sympathetic drive. Therapy with continuous positive airway pressure has been demonstrated to improve cardiopulmonary hemodynamics in patients with OSA and may reverse the endothelial cell dysfunction. Limited availability of diagnostic measures and unawareness of physicians, many patients with OSA remain undiagnosed. Awareness and timely initiation of an effective treatment may prevent potential deleterious cardiovascular effects of OSA. Key words: Obstructive Sleep apnea, Hypertension, Atherosclerosis, Continuous positive airway pressure.   doi:10.3329/uhj.v4i2.2075 University Heart Journal Vol. 4 No. 2 July 2008 p.41-45


1992 ◽  
Vol 145 (2_pt_1) ◽  
pp. 377-382 ◽  
Author(s):  
T. Douglas Bradley ◽  
Richard M. Holloway ◽  
Peter R. McLaughlin ◽  
Bette L. Ross ◽  
Janice Walters ◽  
...  

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