scholarly journals How Do We Monitor Oxygenation during the Management of PPHN? Alveolar, Arterial, Mixed Venous Oxygen Tension or Peripheral Saturation?

Children ◽  
2020 ◽  
Vol 7 (10) ◽  
pp. 180
Author(s):  
Praveen Chandrasekharan ◽  
Munmun Rawat ◽  
Satyan Lakshminrusimha
Keyword(s):  
Oxygen Tension ◽  
Oxygen Delivery ◽  
Randomized Clinical Trials ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Venous Catheter ◽  
Supplemental Oxygen ◽  
Target Range ◽  
Randomized Controlled Studies ◽  
Pulmonary Vasodilator ◽  
Mixed Venous

Oxygen is a pulmonary vasodilator and plays an important role in mediating circulatory transition from fetal to postnatal period. Oxygen tension (PO2) in the alveolus (PAO2) and pulmonary artery (PaO2) are the main factors that influence hypoxic pulmonary vasoconstriction (HPV). Inability to achieve adequate pulmonary vasodilation at birth leads to persistent pulmonary hypertension of the newborn (PPHN). Supplemental oxygen therapy is the mainstay of PPHN management. However, optimal monitoring and targeting of oxygenation to achieve low pulmonary vascular resistance (PVR) and optimizing oxygen delivery to vital organs remains unknown. Noninvasive pulse oximetry measures peripheral saturations (SpO2) and a target range of 91–95% are recommended during acute PPHN management. However, for a given SpO2, there is wide variability in arterial PaO2, especially with variations in hemoglobin type (HbF or HbA due to transfusions), pH and body temperature. This review evaluates the role of alveolar, preductal, postductal, mixed venous PO2, and SpO2 in the management of PPHN. Translational and clinical studies suggest maintaining a PaO2 of 50–80 mmHg decreases PVR and augments pulmonary vasodilator management. Nevertheless, there are no randomized clinical trials evaluating outcomes in PPHN targeting SpO2 or PO2. Also, most critically ill patients have umbilical arterial catheters and postductal PaO2 may not be an accurate assessment of oxygen delivery to vital organs or factors influencing HPV. The mixed venous oxygen tension from umbilical venous catheter blood gas may assess pulmonary arterial PO2 and potentially predict HPV. It is crucial to conduct randomized controlled studies with different PO2/SpO2 target ranges for the management of PPHN and compare outcomes.

scholarly journals How Do We Monitor Oxygenation During The Management of PPHN? Alveolar, Arterial or Mixed Oxygen Tension or Peripheral Saturation?

2020 ◽  
Author(s):  
Praveen Chandrasekharan ◽  
Munmun Rawat ◽  
Satyan Lakshminrusimha
Keyword(s):  
Oxygen Tension ◽  
Oxygen Delivery ◽  
Randomized Clinical Trials ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Randomized Controlled Studies ◽  
Pulmonary Vasodilator ◽  
Pulmonary Arterial ◽  
Arterial Po2 ◽  
Mixed Venous

Oxygen is a pulmonary vasodilator and plays an important role in mediating circulatory transition from fetal and postnatal period. Alveolar oxygen tension (PAO2) and pulmonary arterial PO2 are the main factors that influence hypoxic pulmonary vasoconstriction (HPV). Inability to achieve adequate pulmonary vasodilation at birth leads to persistent pulmonary hypertension of the newborn (PPHN). Supplemental oxygen is the mainstay of PPHN management. However, optimal monitoring of oxygenation to achieve low pulmonary vascular resistance (PVR) and optimize oxygen delivery to vital organs is not known. Noninvasive pulse oximetry measures peripheral saturations (SpO2) and ranges 91-95% are recommended during acute PPHN management. However, for a given SpO2, there is wide variability in arterial oxygen tension, especially with variations in hemoglobin type (transfusions), pH and body temperature. This review evaluates the role of alveolar, preductal, postductal, and mixed venous oxygen tension and SpO2 in the management of PPHN. Translation and clinical studies suggest maintaining an arterial oxygen tension of 50-80 mmHg to help decrease PVR and optimize pulmonary vasodilator management. Nevertheless, there are no randomized clinical trials evaluating outcomes in PPHN based on targeting SpO2 or PO2. However, most critically ill patients have umbilical arterial catheters and postductal arterial oxygenation may not be an accurate assessment of oxygen delivery to vital organs or factors influencing HPV. The mixed venous oxygen tension from umbilical venous catheter blood gas may assess pulmonary arterial PO2 and potentially predict HPV. It is crucial to conduct randomized controlled studies with different PO2/SpO2 ranges and compare outcomes in PPHN.

Effects of lung hyperinflation and presence of positive end-expiratory pressure on arterial and tissue oxygenation during endotracheal suctioning

1993 ◽  
Vol 2 (4) ◽  
pp. 317-325 ◽  
Author(s):  
D McIntosh ◽  
MM Baun ◽  
J Rogge
Keyword(s):  
Oxygen Tension ◽  
Oxygen Delivery ◽  
Tissue Oxygenation ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Positive End Expiratory Pressure ◽  
Oxygen Extraction Ratio ◽  
Endotracheal Suctioning ◽  
Mixed Venous

PURPOSE: To explore the effects of endotracheal suctioning on mixed venous oxygen tension and other measures of arterial and tissue oxygenation, to determine if these would be clinically useful outcome measures of endotracheal suctioning. BACKGROUND: Measuring arterial oxygenation only as an outcome of endotracheal suctioning can be misleading in that it may appear adequate in the presence of marked decreases in mixed venous oxygen tension, a good indicator of the adequacy of tissue oxygenation. METHODS: Eighteen instrumented and oleic acid-injured animal models of acute respiratory failure undergoing closed-system endotracheal suctioning were studied according to a 2 x 2 factorial design to measure the effects of oxygen inflations at tidal volume or 135% of tidal volume either in the presence or absence of positive end-expiratory pressure. RESULTS: Using multivariate analysis of variance for repeated measures, protocol by time effects for mixed venous oxygen tension, arterial oxygen saturation, arterial oxygen tension, oxygen delivery and oxygen extraction ratio were statistically significant. Changes in mixed venous oxygen tension and arterial oxygen saturation were parallel. CONCLUSIONS: Continuous measurement of mixed venous oxygen tension allows the calculation of oxygen delivery and oxygen extraction ratio, which provide a better estimation of the effects of endotracheal suctioning on tissue oxygenation than arterial oxygen tension alone.

PAO2 and PVO2 interaction on hypoxic pulmonary vasoconstriction

1982 ◽  
Vol 53 (1) ◽  
pp. 134-139 ◽  
Author(s):  
R. D. Pease ◽  
J. L. Benumof ◽  
F. R. Trousdale
Keyword(s):  
Oxygen Tension ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Small Compartment ◽  
Pulmonary Vasoconstriction ◽  
Lung Compartment ◽  
Anesthetized Dogs ◽  
Fraction Of Inspired Oxygen ◽  
Alveolar Oxygen ◽  
Inspired Oxygen ◽  
Mixed Venous

We sought to determine why large lung compartment hypoxic pulmonary vasoconstriction fails to redistribute blood flow at a low fraction of inspired oxygen (FIO2) level (0.06) when the remaining small lung compartment is ventilated with room air. In 10 pentobarbital-anesthetized dogs, we decreased large compartment FIO2 from 1.0 to 0.06 while the small compartment FIO2 was constant at 0.21, 0.3, 0.5, or 1.0. When small compartment FIO2 was 0.21 and 0.3, large compartment FIO2 decreases from 1.0 to 0.15–0.10 caused a disproportionate increase in large compartment pulmonary vascular resistance (PVR) and further large compartment FIO2 decreases from 0.15–0.10 to 0.06 caused a decrease in large compartment PVR while small compartment PVR continued to increase. When small compartment FIO2 was 0.5, large compartment FIO2 decreases caused an increase and then no change in large compartment PVR, while small compartment PVR remained constant. When small compartment FIO2 was 1.0, all large compartment FIO2 decreases caused increases in large compartment PVR, while small compartment PVR remained constant. When small compartment FIO2 was 0.21 and 0.3, small compartment alveolar oxygen tension (PAO2) and PVR were always inversely related. When small compartment FIO2 was 0.21, 0.3, and 0.5, large compartment PVR either decreased or remained constant whenever mixed venous oxygen tension (PVO2) was less than 30–32 Torr and large compartment PAO2 was less than 50–60 Torr. We conclude that both small compartment hypoxic pulmonary vasoconstriction and primarily failure of large compartment hypoxic pulmonary vasoconstriction occurred when large compartment FIO2 was low (0.06) and small compartment FIO2 was 0.21 or 0.3.

Hypoxic Pulmonary Vasoconstriction in Nonventilated Lung Areas Contributes to Differences in Hemodynamic and Gas Exchange Responses to Inhalation of Nitric Oxide 

1997 ◽  
Vol 86 (6) ◽  
pp. 1254-1261 ◽  
Author(s):  
Albert Benzing ◽  
Georg Mols ◽  
Thomas Brieschal ◽  
Klaus Geiger
Keyword(s):  
Nitric Oxide ◽  
Gas Exchange ◽  
Oxygen Tension ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Arterial Oxygen ◽  
Mixed Venous Blood ◽  
Respiratory Response ◽  
Pulmonary Vasoconstriction ◽  
Wide Range ◽  
Mixed Venous

Background Enhancement of hypoxic pulmonary vasoconstriction (HPV) in nonventilated lung areas by almitrine increases the respiratory response to inhaled nitric oxide (NO) in patients with acute respiratory distress syndrome (ARDS). Therefore the authors hypothesized that inhibition of HPV in nonventilated lung areas decreases the respiratory effects of NO. Methods Eleven patients with severe ARDS treated by venovenous extracorporeal lung assist were studied. Patients' lungs were ventilated at a fraction of inspired oxygen (F[I(O2)]) of 1.0. By varying extracorporeal blood flow, mixed venous oxygen tension (P[O2]; partial oxygen pressure in mixed venous blood [PV(O2)]) was adjusted randomly to four levels (means, 47, 54, 64 and 84 mmHg). Extracorporeal gas flow was adjusted to prevent changes in mixed venous carbon dioxide tension [PV(CO2)]). Hemodynamic and gas exchange variables were measured at each level before, during, and after 15 ppm NO. Results Increasing PV(O2) from 47 to 84 mmHg resulted in a progressive decrease in lung perfusion pressure (PAP-PAWP; P < 0.05) and pulmnonary vascular resistance index (PVRI; P < 0.05) and in an increase in intrapulmonary shunt (Q[S]/Q[T]; P < 0.05). PV(CO2) and cardiac index did not change. Whereas the NO-induced reduction in PAP-PAWP was smaller at high PV(O2), NO-induced decrease in Q(S)/Q(T) was independent of baseline PV(O2). In response to NO, arterial P(O2) increased more and arterial oxygen saturation increased less at high compared with low PV(O2). Conclusion In patients with ARDS, HPV in nonventilated lung areas modifies the hemodynamic and respiratory response to NO. The stronger the HPV in nonventilated lung areas the more pronounced is the NO-induced decrease in PAP-PAWP. In contrast, the NO-induced decrease in Q(S)/Q(T) is independent of PV(O2) over a wide range of PV(O2) levels. The effect of NO on the arterial oxygen tension varies with the level of PV(O2) by virtue of its location on the oxygen dissociation curve.

Automated control of oxygen titration in preterm infants on non-invasive respiratory support

2021 ◽  
pp. fetalneonatal-2020-321538
Author(s):  
Peter A Dargaville ◽  
Andrew P Marshall ◽  
Oliver J Ladlow ◽  
Charlotte Bannink ◽  
Rohan Jayakar ◽  
...  
Keyword(s):  
Preterm Infants ◽  
Neonatal Intensive Care ◽  
Supplemental Oxygen ◽  
Respiratory Support ◽  
Target Range ◽  
Manual Control ◽  
Oxygen Control ◽  
Automated Control ◽  
Non Invasive ◽  
Automated Oxygen Control

ObjectiveTo evaluate the performance of a rapidly responsive adaptive algorithm (VDL1.1) for automated oxygen control in preterm infants with respiratory insufficiency.DesignInterventional cross-over study of a 24-hour period of automated oxygen control compared with aggregated data from two flanking periods of manual control (12 hours each).SettingNeonatal intensive care unit.ParticipantsPreterm infants receiving non-invasive respiratory support and supplemental oxygen; median birth gestation 27 weeks (IQR 26–28) and postnatal age 17 (12–23) days.InterventionAutomated oxygen titration with the VDL1.1 algorithm, with the incoming SpO2 signal derived from a standard oximetry probe, and the computed inspired oxygen concentration (FiO2) adjustments actuated by a motorised blender. The desired SpO2 range was 90%–94%, with bedside clinicians able to make corrective manual FiO2 adjustments at all times.Main outcome measuresTarget range (TR) time (SpO2 90%–94% or 90%–100% if in air), periods of SpO2 deviation, number of manual FiO2 adjustments and oxygen requirement were compared between automated and manual control periods.ResultsIn 60 cross-over studies in 35 infants, automated oxygen titration resulted in greater TR time (manual 58 (51–64)% vs automated 81 (72–85)%, p<0.001), less time at both extremes of oxygenation and considerably fewer prolonged hypoxaemic and hyperoxaemic episodes. The algorithm functioned effectively in every infant. Manual FiO2 adjustments were infrequent during automated control (0.11 adjustments/hour), and oxygen requirements were similar (manual 28 (25–32)% and automated 26 (24–32)%, p=0.13).ConclusionThe VDL1.1 algorithm was safe and effective in SpO2 targeting in preterm infants on non-invasive respiratory support.Trial registration numberACTRN12616000300471.

scholarly journals Caries Removal by Chemomechanical (Carisolv™) vs. Rotary Drill: A Systematic Review

2015 ◽  
Vol 9 (1) ◽  
pp. 462-472 ◽  
Author(s):  
Viral P. Maru ◽  
B.S. Shakuntala ◽  
C. Nagarathna
Keyword(s):  
Clinical Trials ◽  
Patient Preference ◽  
Pain Perception ◽  
Randomized Clinical Trials ◽  
Meta Analysis ◽  
Random Effect ◽  
Search Results ◽  
Randomized Controlled Studies ◽  
Caries Removal ◽  
Time Required

Background:Chemomechanical caries removal is an effective alternative to the traditional rotary drilling method. The advantages of chemomechanical techniques in terms of the need for anesthesia, pain perception and patient preference are systematically reviewed and a meta-analysis of the time required for caries removal is reported.Method: Randomized controlled studies of comparison of chemomechanical techniques with conventional rotary drill were selected from a systematic search of standard biomedical databases, including the PubMed and Cochrane clinical trials. Non-repeated search results were screened for relevance and risk of bias assessment, followed by methodology assessment. Statistical models were applied to the outcome parameters - time required, pain perception, need of anesthesia and patient preference - extracted from the studies.Results: Out of the 111 non-repeated search results, 26 studies receiving a low bias score were selected for the review, and 16 randomized clinical trials of rotary and Carisolv techniques were considered for meta-analysis. Meta-analysis by fixed effect as well as random effect models indicate that Carisolv takes more time (3.65 ± 0.05 and 4.09 ± 0.29 min) than rotary drill (8.65 ± 0.09 and 8.97 ± 0.66 min) method. Advantages of reduced pain (14.67 for Carisolvvs.6.76 for rotary drill), need for anesthesia (1.59%vs.10.52%) outweigh the longer time requirement and make it the preferred (18.68%vs.4.69%) method.Conclusion: Chemomechanical techniques stand out as a minimally invasive and preferred method based on the meta-analyses. Evaluation of pain experienced using robust methods is needed to strengthen the evidence for their use.

scholarly journals Automatic Oxygen Delivery System for Premature Babies

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Thao P. Do ◽  
Lindsey J. Eubank ◽  
Devin S. Coulter ◽  
John M. Freihaut ◽  
Carlos E. Guevara ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Oxygen Concentration ◽  
Delivery System ◽  
Pulse Oximeter ◽  
Oxygen Delivery ◽  
Supplemental Oxygen ◽  
Saturation Level ◽  
Blood Oxygen ◽  
Blood Oxygen Saturation ◽  
Oxygen Saturation Level

When an infant is born prematurely, there are a number of health risks. Among these are underdeveloped lungs, which can lead to abnormal gas exchange of oxygen or hypoxemia. Hypoxemia is treated through oxygen therapy, which involves the delivery of supplemental oxygen to the patient but there are risks associated with this method. Risks include retinopathy, which can cause eye damage when oxygen concentration is too high, and brain damage, when the concentration is too low [1]. Supplemental oxygen concentration must be controlled rigorously. Currently healthcare staff monitors infants’ blood oxygen saturation level using a pulse oximeter. They manually adjust the oxygen concentration using an air-oxygen blender. Inconsistent manual adjustments can produce excessive fluctuations and cause the actual oxygen saturation level to deviate from the target value. Precision and accuracy are compromised. This project develops an automatic oxygen delivery system that regulates the supplemental oxygen concentration to obtain a target blood oxygen saturation level. A microprocessor uses a LABVIEW® program to analyze pulse oximeter and analyzer readings and control electronic valves in a redesigned air-oxygen blender. A user panel receives a target saturation level, displays patient data, and signals alarms when necessary. The prototype construction and testing began February 2010.

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