scholarly journals Tidal Ventilation with Dynamic Peep at Birth, But Not a Sustained Inflation, Improves Surfactant Function in Preterm Lambs

2018 ◽  
Vol 54 ◽  
pp. 49-50
Keyword(s):  
Tidal Ventilation ◽  
Sustained Inflation

scholarly journals An individualized approach to sustained inflation duration at birth improves outcomes in newborn preterm lambs

2015 ◽  
Vol 309 (10) ◽  
pp. L1138-L1149 ◽  
Author(s):  
David G. Tingay ◽  
Anna Lavizzari ◽  
Cornelis E. E. Zonneveld ◽  
Anushi Rajapaksa ◽  
Emanuela Zannin ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Lung Injury ◽  
Positive Pressure Ventilation ◽  
Lung Mechanics ◽  
Positive Pressure ◽  
Impedance Tomography ◽  
Tidal Ventilation ◽  
Sustained Inflation ◽  
Volume Response ◽  
The Impact

A sustained first inflation (SI) at birth may aid lung liquid clearance and aeration, but the impact of SI duration relative to the volume-response of the lung is poorly understood. We compared three SI strategies: 1) variable duration defined by attaining volume equilibrium using real-time electrical impedance tomography (EIT; SIplat); 2) 30 s beyond equilibrium (SIlong); 3) short 30-s SI (SI30); and 4) positive pressure ventilation without SI (no-SI) on spatiotemporal aeration and ventilation (EIT), gas exchange, lung mechanics, and regional early markers of injury in preterm lambs. Fifty-nine fetal-instrumented lambs were ventilated for 60 min after applying the allocated first inflation strategy. At study completion molecular and histological markers of lung injury were analyzed. The time to SI volume equilibrium, and resultant volume, were highly variable; mean (SD) 55 (34) s, coefficient of variability 59%. SIplat and SIlong resulted in better lung mechanics, gas exchange and lower ventilator settings than both no-SI and SI30. At 60 min, alveolar-arterial difference in oxygen was a mean (95% confidence interval) 130 (13, 249) higher in SI30 vs. SIlong group (two-way ANOVA). These differences were due to better spatiotemporal aeration and tidal ventilation, although all groups showed redistribution of aeration towards the nondependent lung by 60 min. Histological lung injury scores mirrored spatiotemporal change in aeration and were greatest in SI30 group ( P < 0.01, Kruskal-Wallis test). An individualized volume-response approach to SI was effective in optimizing aeration, homogeneous tidal ventilation, and respiratory outcomes, while an inadequate SI duration had no benefit over positive pressure ventilation alone.

scholarly journals Sustained Inflation Reduces Pulmonary Blood Flow during Resuscitation with an Intact Cord

Children ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 353
Author(s):  
Jayasree Nair ◽  
Lauren Davidson ◽  
Sylvia Gugino ◽  
Carmon Koenigsknecht ◽  
Justin Helman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Perinatal Asphyxia ◽  
Arterial Blood Flow ◽  
Positive Pressure ◽  
Optimal Timing ◽  
Delayed Cord Clamping ◽  
Arterial Blood ◽  
Cord Clamping ◽  
Sustained Inflation ◽  
Near Term

The optimal timing of cord clamping in asphyxia is not known. Our aims were to determine the effect of ventilation (sustained inflation–SI vs. positive pressure ventilation–V) with early (ECC) or delayed cord clamping (DCC) in asphyxiated near-term lambs. We hypothesized that SI with DCC improves gas exchange and hemodynamics in near-term lambs with asphyxial bradycardia. A total of 28 lambs were asphyxiated to a mean blood pressure of 22 mmHg. Lambs were randomized based on the timing of cord clamping (ECC—immediate, DCC—60 s) and mode of initial ventilation into five groups: ECC + V, ECC + SI, DCC, DCC + V and DCC + SI. The magnitude of placental transfusion was assessed using biotinylated RBC. Though an asphyxial bradycardia model, 2–3 lambs in each group were arrested. There was no difference in primary outcomes, the time to reach baseline carotid blood flow (CBF), HR ≥ 100 bpm or MBP ≥ 40 mmHg. SI reduced pulmonary (PBF) and umbilical venous (UV) blood flow without affecting CBF or umbilical arterial blood flow. A significant reduction in PBF with SI persisted for a few minutes after birth. In our model of perinatal asphyxia, an initial SI breath increased airway pressure, and reduced PBF and UV return with an intact cord. Further clinical studies evaluating the timing of cord clamping and ventilation strategy in asphyxiated infants are warranted.

Ventilatory responses to CO2 and lung inflation in tonic versus phasic REM sleep

1979 ◽  
Vol 47 (6) ◽  
pp. 1304-1310 ◽  
Author(s):  
C. E. Sullivan ◽  
E. Murphy ◽  
L. F. Kozar ◽  
E. A. Phillipson
Keyword(s):  
Eye Movements ◽  
Rem Sleep ◽  
Slow Wave Sleep ◽  
Minute Volume ◽  
Sleep State ◽  
Lung Inflation ◽  
Ventilatory Responses ◽  
Sustained Inflation ◽  
Per Se ◽  
Phasic Rem Sleep

Ventilatory responses to CO2 and to lung inflation were compared in four dogs during tonic and phasic segments of rapid-eye-movement (REM) sleep. Phasic REM sleep (P-REM) was identified by the presence of bursts of rapid eye movements, visible muscle twitchings, and frequent phasic discharges in the nuchal electromyogram. These features were absent during tonic REM sleep (T-REM). During P-REM the response of minute volume of ventilation (VI) to progressive hypercapnia (0.58 +/- 0.19 (l/min)/Torr, mean +/- SE) was significantly less than in slow-wave sleep (SWS) (1.40 +/- 0.14; P less than 0.05). In contrast, during T-REM the response (1.48 +/- 0.19) was similar to that in SWS. Similarly, during P-REM the duration of apnea (5.9 +/- 1.5 s) elicited by sustained inflation of the lungs with 1.0 liter of air, was significantly shorter than in SWS (25.8 +/- 0.8); in contrast, during T-REM the duration of apnea (17.8 +/- 3.6) was similar to that in SWS. The results indicate that previously described decreases in VI responses to CO2 and apneic responses to lung inflation during P-REM, compared to SWS, are related to the phasic phenomena of REM sleep, rather than to the REM sleep state per se.

scholarly journals Asphyxiated Female and Male Newborn Piglets Have Similar Outcomes With Different Cardiopulmonary Resuscitation Interventions

2020 ◽  
Vol 8 ◽  
Author(s):  
Seung Yeon Kim ◽  
Gyu-Hong Shim ◽  
Megan O'Reilly ◽  
Po-Yin Cheung ◽  
Tze-Fun Lee ◽  
...  
Keyword(s):  
Cardiopulmonary Resuscitation ◽  
Cerebral Oxygenation ◽  
Secondary Analysis ◽  
Spontaneous Circulation ◽  
Male And Female ◽  
Newborn Piglets ◽  
Sustained Inflation ◽  
Significant Difference ◽  
Tissue Homogenates ◽  
Males And Females

Background: Male newborns have a greater risk of poor cardiovascular and respiratory outcomes compared to females. The mechanisms associated with the “male disadvantage” remains unclear. We have previously shown no difference between male and female newborn piglets during hypoxia, asphyxia, resuscitation, and post-resuscitation recovery. However, it is unknown if there are differences in resuscitation outcomes between males and females during different cardiopulmonary resuscitation techniques.Intervention and Measurements: Secondary analysis of 184 term newborn mixed breed duroc piglets (1–3 days of age, weighing 2.0 (0.2) kg) from seven different studies, which were exposed to 30–50 min of normocapnic hypoxia followed by asphyxia until asystole. This was followed by cardiopulmonary resuscitation. For the analysis, piglets were divided into male and female groups, as well as resuscitation technique groups (sustained inflation, 3:1 compression-to-ventilation ratio, or asynchronous ventilations during chest compressions). Cardiac function, carotid blood flow, and cerebral oxygenation were continuously recorded throughout the experiment.Main results: Regardless of resuscitation technique, there was no significant difference between males and females in the number achieving return of spontaneous circulation (ROSC) [95/123 (77%) vs. 48/61 (79%)], the time to achieve ROSC [112 (80–185) s vs. 110 (77–186) s], and the 4-h survival rate [81/95 (85%) vs. 40/48 (83%)]. Levels of the injury markers interleukin (IL)−1ß, IL-6, IL-8, and tumor necrosis factor-α in frontoparietal cortex tissue homogenates were similar between males and females.Conclusions: Regardless of resuscitation technique, there was no significant effect of sex on resuscitation outcome, survival, and hemodynamic recovery in asphyxiated newborn piglets.

Sustained Inflation for Lung Aeration After Birth

NeoReviews ◽  
2016 ◽  
Vol 17 (1) ◽  
pp. e8-e17 ◽  
Author(s):  
E. E. Foglia ◽  
H. Kirpalani
Keyword(s):  
Lung Aeration ◽  
Sustained Inflation

Erratum to "A reconciliation of continuous and tidal ventilation gas exchange models"

1997 ◽  
Vol 109 (2) ◽  
pp. 195
Author(s):  
M.C. Sainsbury ◽  
A. Lorenzi ◽  
E.M. Williams ◽  
C.E.W. Hahn
Keyword(s):  
Gas Exchange ◽  
Tidal Ventilation

scholarly journals Revisiting atelectasis in lung units with low ventilation/perfusion ratios

2019 ◽  
Vol 126 (3) ◽  
pp. 782-786 ◽  
Author(s):  
James P. Butler ◽  
Atul Malhotra ◽  
Stephen H. Loring
Keyword(s):  
Gas Exchange ◽  
Convective Transport ◽  
Oxygen Absorption ◽  
Test Unit ◽  
Case Scenario ◽  
Worst Case ◽  
Effect Change ◽  
Pressure Drops ◽  
Tidal Ventilation ◽  
Airway Caliber

Patients on high inspired O2 concentrations are at risk of atelectasis, a problem that has been quantitatively assessed using analysis of ratio of ventilation to perfusion (V̇a/Q̇) equations. This approach ignores the potential of the elastic properties of the lung to support gas exchange through “apneic” oxygenation in units with no tidal ventilation, and is based on an error in the conservation of mass equations. To fill this gap, we correct the error and compare the pressure drops associated with apneic gas exchange with the pressure differences that can be supported by lung recoil. We analyze a worst case scenario: a small test unit in the Weibel model A tree structure with zero tidal ventilation, 100% inspired O2, the rest of the lung being normally ventilated tidally. We first computed the gas flux to the (unventilated) test unit and estimated the associated pressure drops. We then computed the difference in local gas pressure relative to the surrounding lung that would cause the unit to collapse. We compared these two, and finally computed the degree of airway narrowing that would effect change from the stable (apneic gas exchange) regime to the unstable regime leading to collapse. We find that except under extreme conditions of loss of airway caliber exceeding roughly 90%, lung recoil is sufficient to maintain oxygenation through convective transport alone. We further argue that the fundamental V̇a/Q̇ equations are invalid in these circumstances, and that the issue of atelectasis in low V̇a/Q̇ will require modifications to account for this additional mode of gas exchange. NEW & NOTEWORTHY Breathing high concentrations of oxygen increases the likelihood of atelectasis because of oxygen absorption, which is thought to be inevitable in regions with relatively low ventilation/perfusion ratios. However, airspaces of the lung resist collapse because of the forces of interdependence, and can, with low or even zero active tidal ventilation, draw in an inspiratory flow of oxygen sufficient to replace the oxygen consumed, thus preventing collapse of airspaces served by all but the most narrowed airways.

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