scholarly journals Bidirectional Ductal Shunting and Preductal to Postductal Oxygenation Gradient in Persistent Pulmonary Hypertension of the Newborn

Children ◽  
2020 ◽  
Vol 7 (9) ◽  
pp. 137
Author(s):  
Amy Lesneski ◽  
Morgan Hardie ◽  
William Ferrier ◽  
Satyan Lakshminrusimha ◽  
Payam Vali
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Pulmonary Blood Flow ◽  
Ductus Arteriosus ◽  
Arterial Oxygen Tension ◽  
Persistent Pulmonary Hypertension ◽  
Arterial Oxygen ◽  
Meconium Aspiration ◽  
Arterial Blood Gas ◽  
Arterial Blood

Background: The aim was to evaluate the relationship between the direction of the patent ductus arteriosus (PDA) shunt and the pre- and postductal gradient for arterial blood gas (ABG) parameters in a lamb model of meconium aspiration syndrome (MAS) with persistent pulmonary hypertension of the newborn (PPHN). Methods: PPHN was induced by intermittent umbilical cord occlusion and the aspiration of meconium through the tracheal tube. After delivery, 13 lambs were ventilated and simultaneous 129 pairs of pre- and postductal ABG were drawn (right carotid and umbilical artery, respectively) while recording the PDA and the carotid and pulmonary blood flow. Results: Meconium aspiration resulted in hypoxemia. The bidirectional ductal shunt had a lower postductal partial arterial oxygen tension ([PaO2] with lower PaO2/FiO2 ratio—97 ± 36 vs. 130 ± 65 mmHg) and left pulmonary flow (81 ± 52 vs. 133 ± 82 mL/kg/min). However, 56% of the samples with a bidirectional shunt had a pre- and postductal saturation gradient of < 3%. Conclusions: The presence of a bidirectional ductal shunt is associated with hypoxemia and low pulmonary blood flow. The absence of a pre- and postductal saturation difference is frequently observed with bidirectional right-to-left shunting through the PDA, and does not exclude a diagnosis of PPHN in this model.

scholarly journals Randomized Trial of Oxygen Saturation Targets during and after Resuscitation and Reversal of Ductal Flow in an Ovine Model of Meconium Aspiration and Pulmonary Hypertension

Children ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 594
Author(s):  
Amy L. Lesneski ◽  
Payam Vali ◽  
Morgan E. Hardie ◽  
Satyan Lakshminrusimha ◽  
Deepika Sankaran
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Oxygen Saturation ◽  
Ductus Arteriosus ◽  
Neonatal Resuscitation ◽  
Meconium Aspiration Syndrome ◽  
Ovine Model ◽  
Neurodevelopmental Outcomes ◽  
Meconium Aspiration ◽  
Blood Flows

Neonatal resuscitation (NRP) guidelines suggest targeting 85–95% preductal SpO2 by 10 min after birth. Optimal oxygen saturation (SpO2) targets during resuscitation and in the post-resuscitation management of neonatal meconium aspiration syndrome (MAS) with persistent pulmonary hypertension (PPHN) remains uncertain. Our objective was to compare the time to reversal of ductal flow from fetal pattern (right-to-left), to left-to-right, and to evaluate pulmonary (QPA), carotid (QCA)and ductal (QDA) blood flows between standard (85–94%) and high (95–99%) SpO2 targets during and after resuscitation. Twelve lambs asphyxiated by endotracheal meconium instillation and cord occlusion to induce MAS and PPHN were resuscitated per NRP guidelines and were randomized to either standard (85–94%) or high (95–99%) SpO2 targets. Out of twelve lambs with MAS and PPHN, six each were randomized to standard and high SpO2 targets. Median [interquartile range] time to change in direction of blood flow across the ductus arteriosus from right-to-left, to left-to-right was significantly shorter with high SpO2 target (7.4 (4.4–10.8) min) compared to standard SpO2 target (31.5 (21–66.2) min, p = 0.03). QPA was significantly higher during the first 10 min after birth with higher SpO2 target. At 60 min after birth, the QPA, QCA and QDA were not different between the groups. To conclude, targeting SpO2 of 95–99% during and after resuscitation may hasten reversal of ductal flow in lambs with MAS and PPHN and transiently increase QPA but no differences were observed at 60 min. Clinical studies comparing low and high SpO2 targets assessing hemodynamics and neurodevelopmental outcomes are warranted.

Effect of Intraoperative PEEP Application on Colonic Anastomoses Healing: An Experimental Animal Study

2016 ◽  
Vol 101 (1-2) ◽  
pp. 24-34 ◽  
Author(s):  
Mehmet Akif Turkoglu ◽  
Erdal Birol Bostancı ◽  
Hasan Bilgili ◽  
Yıldız Turkoglu ◽  
Ümit Karadeniz ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Healing Process ◽  
Peep Level ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Colonic Anastomoses ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Bursting Pressures ◽  
Group 2

This study aimed to assess the effect of intraoperative positive end–expiratory pressure (PEEP) intervention on the healing of colonic anastomoses in rabbits. A total of 32 New Zealand type male rabbits were divided into 2 groups of 16 animals each. Following ventilation with tracheostomy, colonic resection and anastomosis were performed in both groups. Although 10 cm of H2O PEEP level was applied in group 1 (PEEP), group 2 [zero end-expiratory pressure (ZEEP)] was ventilated without PEEP throughout the surgery. Half of both the PEEP and ZEEP group animals were killed on the third postoperative day, whereas the remaining half were killed on the seventh. Anastomotic bursting pressures, the tissue concentrations in hydroxyproline, and histologic assessments were performed. Intraoperative oxygen saturation and postoperative arterial blood gas parameters were also compared. On the first postoperative day, both arterial oxygen tension (PO2) and oxygen saturation (SO2) in the PEEP group were significantly higher than in the ZEEP group. On the seventh postoperative day, the bursting pressures of the anastomoses were significantly higher in the PEEP group; however, the hydroxyproline content was significantly lower in the PEEP group than in the ZEEP group. At day 7, the PEEP group was significantly associated with increased neoangiogenesis compared with the ZEEP group. The anastomotic healing process is positively influenced by the intraoperative PEEP application.

Development of pulmonary vascular response to oxygen

1988 ◽  
Vol 254 (3) ◽  
pp. H542-H546 ◽  
Author(s):  
F. C. Morin ◽  
E. A. Egan ◽  
W. Ferguson ◽  
C. E. Lundgren
Keyword(s):  
Blood Flow ◽  
Right Ventricular ◽  
Oxygen Tension ◽  
Pulmonary Circulation ◽  
Pulmonary Blood Flow ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Absolute Pressure ◽  
Fetal Lamb ◽  
Near Term

The ability of the pulmonary circulation of the fetal lamb to respond to a rise in oxygen tension was studied from 94 to 146 days of gestation. The unanesthetized ewe breathed room air at normal atmospheric pressure, followed by 100% oxygen at three atmospheres absolute pressure in a hyperbaric chamber. In eleven near-term lambs (132 to 146 days of gestation), fetal arterial oxygen tension (PaO2) increased from 25 +/- 1 to 55 +/- 6 Torr (mean +/- SE), which increased the proportion of right ventricular output distributed to the fetal lungs from 8 +/- 1 to 59 +/- 5%. In five very immature lambs (94 to 101 days of gestation), fetal PaO2 increased from 27 +/- 1 to 174 +/- 70 Torr, but the proportion of right ventricular output distributed to the lung did not change, 8 +/- 1 to 9 +/- 1%. In five of the near-term lambs, pulmonary blood flow was measured. It increased from 34 +/- 3 to 298 +/- 35 ml.kg fetal wt-1.min-1, an 8.8-fold increase. We conclude that the pulmonary circulation of the fetal lamb does not respond to an increase in oxygen tension before 101 days of gestation; however, near term an increase in oxygen tension alone can induce the entire increase in pulmonary blood flow that normally occurs after the onset of breathing at birth.

EFFECT OF THE PATENT DUCTUS ARTERIOSUS ON THE PULMONARY BLOOD FLOW, BLOOD VOLUME, HEART RATE, BLOOD PRESSURE, ARTERIAL BLOOD GASES AND pH

PEDIATRICS ◽  
1950 ◽  
Vol 6 (4) ◽  
pp. 557-572
Author(s):  
DONALD E. CASSELS ◽  
MINERVA MORSE ◽  
W. E. ADAMS
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Patent Ductus Arteriosus ◽  
Blood Volume ◽  
Pulmonary Blood Flow ◽  
Ductus Arteriosus ◽  
Blood Gases ◽  
Arterial Blood Gases ◽  
Arterial Blood ◽  
Patent Ductus

The effect of the patent ductus arteriosus on the circulation and on the arterial blood gases and pHs has been studied. The pulmonary blood flow diminished 19.6 to 61.8% following ligation in 12 cases examined. The blood volume diminished following closure of the ductus in most cases. Likewise, the heart rate lessened and the pulse pressure was lower after surgery. Arterial oxygen saturation was low preoperatively in some cases and in most instances postoperatively, and this low value sometimes persisted. Some aspects of the data presented have been discussed in detail.

Hypoxemia and pulmonary gas exchange during hemodialysis

1981 ◽  
Vol 50 (2) ◽  
pp. 259-264 ◽  
Author(s):  
R. W. Patterson ◽  
A. R. Nissenson ◽  
J. Miller ◽  
R. T. Smith ◽  
R. G. Narins ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Oxygen Tension ◽  
Minute Ventilation ◽  
Arterial Oxygen Tension ◽  
Pulmonary Gas Exchange ◽  
Arterial Oxygen ◽  
Exchange Relationships ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Alveolar Oxygen

With measured values of arterial blood gas tensions, of expired respiratory gas fractions, and volume of the expired ventilation, the determinants of alveolar oxygen tension (PAO2) were used to evaluate their influence on the development of the arterial hypoxemia that occurs in spontaneously breathing patients undergoing hemodialysis using an acetate dialysate. Dialysis produced no significant changes in the alveolar-arterial O2 tension gradient (AaDO2). The extracorporeal dialyzer removed an average of 30 ml.m-2.min-1 of CO2. Accordingly the pulmonary gas exchange ratio (R) dropped from a mean predialysis value of 0.81 to 0.62 (P less than 0.001). The arterial CO2 tension remained constant throughout, whereas the minute ventilation, both total (P less than 0.01) and alveolar (P less than 0.01), decreased during dialysis. This decrease in ventilation accounts for more than 80% of the fall in PAO2. During dialysis there was a decrease (P less than 0.001) in arterial oxygen tension (PaO2), which varied among the individuals from 9 to 23% of control. During the postdialysis hour PaO2 returns to control values concomitant with increase in ventilation. The quantitative gas exchange relationships among R, alveolar ventilation, and AaDO2 predict the PaO2 values actually measured.

Pulmonary effects of intravenous atropine induce ventilation perfusion mismatch

2014 ◽  
Vol 92 (5) ◽  
pp. 399-404 ◽  
Author(s):  
Romolo J. Gaspari ◽  
David Paydarfar
Keyword(s):  
Blood Flow ◽  
Gas Exchange ◽  
Pulmonary Blood Flow ◽  
Gas Analysis ◽  
Pulmonary Gas Exchange ◽  
Blood Gas ◽  
Arterial Blood Gas ◽  
Anticholinergic Medications ◽  
Arterial Blood ◽  
Intravenous Atropine

Atropine is used for a number of medical conditions, predominantly for its cardiovascular effects. Cholinergic nerves that innervate pulmonary smooth muscle, glands, and vasculature may be affected by anticholinergic medications. We hypothesized that atropine causes alterations in pulmonary gas exchange. We conducted a prospective interventional study with detailed physiologic recordings in anesthetized, spontaneously breathing rats (n = 8). Animals breathing a normoxic gas mixture titrated to a partial arterial pressure of oxygen of 110–120 were exposed to an escalating dose of intravenous atropine (0.001, 0.01, 0.1, 5.0, and 20.0 mg/kg body mass). Arterial blood gas measurements were recorded every 2 min (×5) at baseline, and following each of the 5 doses of atropine. In addition, the animals regional pulmonary blood flow was measured using neutron-activated microspheres. Oxygenation decreased immediately following intravenous administration of atropine, despite a small increase in the volume of inspired air with no change in respiratory rate. Arterial blood gas analysis showed an increase in pulmonary dysfunction, characterized by a widening of the alveolar–arteriole gradient (p < 0.003 all groups except for the lowest dose of atropine). The microsphere data demonstrates an abrupt and marked heterogeneity of pulmonary blood flow following atropine treatment. In conclusion, atropine was found to decrease pulmonary gas exchange in a dose-dependent fashion in this rat model.

Comparison of pulmonary function in isoflurane anaesthetized ventilated sheep (Ovis aries) following administration of intravenous xylazine versus medetomidine

2021 ◽  
pp. 002367722098336
Author(s):  
Anthea L Raisis ◽  
Giselle L Hosgood ◽  
Nicholas Crawford ◽  
Sabine Kästner ◽  
Gabrielle C Musk ◽  
...  
Keyword(s):  
Pulmonary Function ◽  
Structural Changes ◽  
Arterial Oxygen Tension ◽  
Blood Gas Analysis ◽  
Gas Analysis ◽  
Ovis Aries ◽  
Arterial Oxygen ◽  
Mixed Effect ◽  
Arterial Blood Gas ◽  
Arterial Blood

Alpha2 receptor agonists (alpha2-agonists) are useful sedative and analgesic agents in sheep, but have adverse pulmonary effects, which are reportedly similar between different alpha2-agonists. This randomized crossover study compared pulmonary function after intravenous administration of an alpha2-agonist, either xylazine or an equipotent dose of medetomidine in 34 female sheep anaesthetized twice. Pulmonary function was assessed using spirometry, volumetric capnography, arterial blood gas analysis 1 min prior to, and 5 and 10 min after administration of the allocated alpha 2 agonist drug. Pulmonary structural changes were subsequently assessed using computed tomography (CT). Tachypnoea or hypoxaemia prompted reversal with atipamezole and exclusion of data. Data were analysed for a fixed effect of drug using a mixed effect linear model with significance set at p < 0.05. Ten sheep administered xylazine required atipamezole while none of sheep receiving medetomidine did. Xylazine produced significantly higher respiratory frequency, airway pressures, airway resistance and arterial carbon dioxide (CO2), and lower dynamic compliance, tidal volume, CO2 elimination and end tidal CO2 tension and arterial oxygen tension than medetomidine. This was associated with a significantly lower % of aerated tissue and higher % poorly and non-aerated tissue in CT images of sheep receiving xylazine versus medetomidine. In conclusion, xylazine administration produced marked decreases in pulmonary function, in ventilated isoflurane anaesthetized sheep, when compared to an equipotent dose of medetomidine when administered as an intravenous bolus supporting the use of medetomidine when alpha2-agonists are required.

Achieving optimal pulmonary blood flow in the first-stage of palliation in early infancy for complex cardiac defects with hypoplastic left ventricles

1995 ◽  
Vol 5 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Tetsuya Kitagawa ◽  
Itsuo Katoh ◽  
Yoshiaki Fukumura ◽  
Masanori Yoshizumi ◽  
Yutaka Masuda ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Arterial Oxygen Tension ◽  
Postoperative Mortality ◽  
Arterial Oxygen ◽  
Optimal Size ◽  
Mean Airway Pressure ◽  
Rigid Model ◽  
Pulmonary Arterial ◽  
Left Heart Syndrome

AbstractThe aim of the study was to determine the optimal size and technique for construction of the systemic-to-pulmonary arterial shunt which will provide suitable pulmonary blood flow in first-stage Norwood palliation for hypoplastic left heart syndrome in neonates. Our clinical experience suggested that an arterial oxygen tension of about 30 mm Hg immediately after cardiopulmonary bypass, with the patients being ventilated at the lowest possible mean airway pressure with an FiO2of 1.0, provided a suitable pulmonary-to-systemic flow ratio. We also aimed to clarify the characteristics of pulmonary blood flow in accordance with the size of the shunt and the change in the pulmonary vascular resistance in a simplified rigid model of the Norwood procedure. A hole of2.0 mm diameter proved adequate to provide a suitable pulmonary blood flow of 200−300 mlx002F;min in the presence of a pressure gradient of 20−40 mm Hg between the systemic and pulmonary circulations in neonates weighing 3 kg. A short central shunt with a prosthesis of4 mm in diameter produced an excessive flow of pulmonary blood. Our data suggest that using a smaller shunt than that commonly used is necessary to decrease the early and intermediate postoperative mortality. A prosthesis of 3.0 or 3.5 mm in diameter arising from the brachiocephalic artery would be acceptable and can be recommended for first-stage Norwood palliation in small infants, especially in view of the operative difficulties encountered in taking down the shunt at the time of subsequent operations.

Matching and mismatching ventilation and perfusion in the lung

1996 ◽  
Vol 16 (3) ◽  
pp. 23-27 ◽  
Author(s):  
RS Misasi ◽  
JL Keyes
Keyword(s):  
Blood Flow ◽  
Regional Differences ◽  
Pulmonary Blood Flow ◽  
Healthy Adults ◽  
Gas Composition ◽  
Blood Gas ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Different Types ◽  
Ventilation And Perfusion

Arterial blood-gas composition is determined by ventilation, pulmonary blood flow, and by how ventilation is matched to blood flow in the lungs. In healthy adults there are regional differences in both ventilation and blood flow in the lungs and the distribution of blood flow tends to parallel that of ventilation. Ventilation and blood flow can become mismatched in a variety of disease processes that affect the lungs. Mismatching of ventilation and perfusion causes decreased PaO2, may change PaCO2, and increases AaDO2 difference. Many different types of interventions are frequently necessary to treat mismatching of ventilation and perfusion.

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