scholarly journals Therapeutic hypercapnia for prevention of secondary ischemia after severe subarachnoid hemorrhage: physiological responses to continuous hypercapnia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christian Stetter ◽  
Franziska Weidner ◽  
Nadine Lilla ◽  
Judith Weiland ◽  
Ekkehard Kunze ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Cardiac Output ◽  
Subarachnoid Hemorrhage ◽  
Partial Pressure ◽  
Rebound Effect ◽  
Target Range ◽  
Tissue Oxygen Saturation ◽  
Arterial Partial Pressure ◽  
Optimum Duration ◽  
Arterial Blood

AbstractTemporary hypercapnia has been shown to increase cerebral blood flow (CBF) and might be used as a therapeutical tool in patients with severe subarachnoid hemorrhage (SAH). It was the aim of this study was to investigate the optimum duration of hypercapnia. This point is assumed to be the time at which buffer systems become active, cause an adaptation to changes of the arterial partial pressure of carbon dioxide (PaCO2) and annihilate a possible therapeutic effect. In this prospective interventional study in a neurosurgical ICU the arterial partial pressure of carbon dioxide (PaCO2) was increased to a target range of 55 mmHg for 120 min by modification of the respiratory minute volume (RMV) one time a day between day 4 and 14 in 12 mechanically ventilated poor-grade SAH-patients. Arterial blood gases were measured every 15 min. CBF and brain tissue oxygen saturation (StiO2) were the primary and secondary end points. Intracranial pressure (ICP) was controlled by an external ventricular drainage. Under continuous hypercapnia (PaCO2 of 53.17 ± 5.07), CBF was significantly elevated between 15 and 120 min after the start of hypercapnia. During the course of the trial intervention, cardiac output also increased significantly. To assess the direct effect of hypercapnia on brain perfusion, the increase of CBF was corrected by the parallel increase of cardiac output. The maximum direct CBF enhancing effect of hypercapnia of 32% was noted at 45 min after the start of hypercapnia. Thereafter, the CBF enhancing slowly declined. No relevant adverse effects were observed. CBF and StiO2 reproducibly increased by controlled hypercapnia in all patients. After 45 min, the curve of CBF enhancement showed an inflection point when corrected by cardiac output. It is concluded that 45 min might be the optimum duration for a therapeutic use and may provide an optimal balance between the benefits of hypercapnia and risks of a negative rebound effect after return to normal ventilation parameters.Trial registration: The study was approved by the institutional ethics committee (AZ 230/14) and registered at ClinicalTrials.gov (Trial-ID: NCT01799525). Registered 01/01/2015.

scholarly journals Dose Optimization Study of Therapeutic Hypercapnia for Prevention of Secondary Ischemia After Severe Subarachnoid Hemorrhage

2021 ◽  
Author(s):  
Christian Stetter ◽  
Franziska Weidner ◽  
Nadine Lilla ◽  
Judith Weiland ◽  
Ekkehard Kunze ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Subarachnoid Hemorrhage ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Rebound Effect ◽  
Comparative Trial ◽  
Target Range ◽  
Tissue Oxygen Saturation ◽  
Enhancing Effect ◽  
Poor Grade ◽  
Arterial Blood

Abstract BackgroundAim of this study was to investigate the time point at which the cerebral blood flow (CBF) enhancing effect of controlled hypercapnia in patients with severe aneurysmal subarachnoid hemorrhage (SAH) starts to extenuate. This point is assumed to be the time at which buffer systems become active and annihilate a possible therapeutic effect. MethodsIn this prospective interventional study in a neurosurgical ICU the arterial partial pressure of carbon dioxide (PaCO2) was increased to a target range of 50 - 55 mmHg for 120 minutes by modification of the respiratory minute volume (RMV) one time a day between day 4 and 14 in 12 mechanically ventilated poor-grade SAH-patients. Arterial blood gases were measured every 15 minutes. CBF and brain tissue oxygen saturation (StiO2) were the primary and secondary end points. Intracranial pressure (ICP) was controlled by an external ventricular drainage. ResultsUnder continuous hypercapnia (PaCO2 of 53.17 ± 5.07), CBF was significantly elevated between 15 and 120 minutes after the start of hypercapnia. During the course of the trial intervention, cardiac output also increased significantly. To assess the direct effect of hypercapnia on brain perfusion, the increase of CBF was corrected by the parallel increase of cardiac output. The maximum direct CBF enhancing effect of hypercapnia of 31% was noted at 45 minutes after the start of hypercapnia. Thereafter, the CBF enhancing slowly declined. No relevant adverse effects were observed. Conclusion CBF and StiO2 reproducibly increased by controlled hypercapnia in all patients. After 45 minutes, the curve of CBF enhancement showed an inflection point when corrected by cardiac output. Temporary hypercapnia of 45 minutes is, thus, likely to be the optimum duration for a therapeutic use and for a controlled comparative trial. Longer intervals bear the risk of a negative rebound effect after return to normal ventilation parameters and may be counterproductive inducing ischemia in a state of critical perfusion after SAH. Trial registrationThe study was approved by the institutional ethics committee (AZ 230/14) and registered at ClinicalTrials.gov (Trial-ID: NCT01799525). Registered 01 January 2015. Retrospectively registered.

scholarly journals Observation on the Nursing Effect of Prone Position Ventilation Applied to Children with Respiratory Failure

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Aili Peng ◽  
Litao Guo ◽  
Jing Xu ◽  
Jingrong Fan
Keyword(s):  
Carbon Dioxide ◽  
Respiratory Failure ◽  
Partial Pressure ◽  
Prone Position ◽  
Pediatric Patients ◽  
Oxygenation Index ◽  
Control Group ◽  
Arterial Partial Pressure ◽  
Arterial Blood ◽  
Experimental Group

Objective — To compare the effects of two prone position ventilation methods on children with respiratory failure, to obtain a safer and more effective way to guide clinical nursing work. Methods — 48 cases of children who were admitted to the intensive care unit of our hospital from February 2018 to August 2019 and applied mechanical ventilation were divided into groups based on a random number table. The odd numbers were included in the experimental group (continuous prone position ventilation group, the duration of continuous prone position exceeded 12 hours, a total of 25 cases). The even numbers were included in the control group (intermittent prone position ventilation group, prone position for 3 hours at a time, alternating with supine position and lateral position, total prone position duration 12 hours, a total of 23 cases). Oxygenation index (OI), PH value, arterial partial pressure of carbon dioxide (PCO2), arterial partial pressure of oxygen (PO2) at 24h, 48h, 72h of the two groups of children, as well as their ventilator use time and ICU hospital stay were compared. Results — Continuous prone position ventilation and intermittent prone position ventilation have no statistical significance on arterial blood carbon dioxide partial pressure (PaCO2), arterial blood oxygen partial pressure (PaO2), ventilator duration, ICU length of stay in children with respiratory failure (P>0.05), but with the increase of the total length of the prone position, when reaching more than 36 hours, the trend of oxygenation index (OI) of the experimental group and the control group can be seen to decline.  Conclusion — In this study, by comparing the effects of two prone position ventilation modes, it was found that intermittent prone position ventilation and continuous prone position ventilation had no difference in the treatment of children with respiratory failure. When children are treated in continuous prone and intermittent prone positions, the total prone position can last up to 36 hours, which can effectively improve the clinical treatment effect. In view of the characteristics of pediatric patients and the difficulty in nursing critically ill patients with tracheal intubation, it is recommended that pediatric patients can use intermittent prone ventilation to complete treatment when the cumulative time in the prone position reaches more than 36 hours.

scholarly journals Observations on some cardiopulmonary effects of midazolam, xylazine and a midazolam / ketamine combination in the goat

1999 ◽  
Vol 70 (3) ◽  
Author(s):  
G.F. Stegmann
Keyword(s):  
Carbon Dioxide ◽  
Blood Pressure ◽  
Partial Pressure ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Minute Volume ◽  
Partial Pressure Of Oxygen ◽  
Arterial Partial Pressure ◽  
Arterial Blood ◽  
Change In Mean

Xylazine, midazolam and a midazolam / ketamine combination were administered to 6 goats in a randomised 3-way block design. All goats received all treatments with at least a 7-day interval between treatments. Statistically significant (P < 0.05) changes were observed in some of the measured cardiopulmonary variables for xylazine and midazolam/ ketamine. Xylazine administration resulted in statistically significant decreases in minute volume, arterial partial pressure of oxygen, heart rate andmeanarterial blood pressure. The increase in arterial partial pressure of carbon dioxide was not statistically significant. For the midazolam / ketamine combination, the decrease in tidal volume was statistically significant, but not the decrease in minute volume and increase in arterial partial pressure of carbon dioxide. The decrease in the arterial partial pressure of oxygen was also statistically significant. The mean arterial blood pressure for the combination was statistically significantly higher compared to xylazine. The changes in cardiopulmonary variables after midazolam administration were not statistically significant, such as tidal and minute volume, arterial partial pressure of oxygen and carbon dioxide. However, clinically significant effects such as hypoventilation and hypoxia were observed after its administration. The change in mean arterial blood pressure was minimal.

scholarly journals Second-generation laryngeal mask airway as an alternative to endotracheal tube during prolonged laparoscopic abdominal surgery: a comparative analysis of intraoperative gas exchanges

2021 ◽  
Author(s):  
S Park ◽  
JE Lee ◽  
GS Choi ◽  
JM Kim ◽  
JS Ko ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Laryngeal Mask Airway ◽  
Abdominal Surgery ◽  
Partial Pressure ◽  
Endotracheal Tube ◽  
Second Generation ◽  
Laryngeal Mask ◽  
Arterial Partial Pressure ◽  
Prolonged Surgery

Introduction: Despite several advantages over endotracheal tube (ETT), laryngeal mask airway (LMA), which is used in emergencies under difficult airway maintenance conditions, is rarely utilized in prolonged surgery. We compared the variables representing intraoperative gas exchange with second-generation LMA and ETT during prolonged laparoscopic abdominal surgery. Methods: Prolonged surgery was defined as a surgery lasting more than 2 h. In total, 394 patients who underwent laparoscopic liver resection via either second-generation LMA or ETT were retrospectively analysed. Parameters including end-tidal pressure of carbon dioxide (ETCO2), tidal volume (TV), respiratory rate (RR), peak inspiratory pressure (PIP), arterial partial pressure of carbon dioxide (PaCO2), pH, and ratio of arterial partial pressure of oxygen to fractional inspired oxygen (PFR) during surgery were compared between the two groups. In addition, the incidence of postoperative pulmonary complications (PPC) including pulmonary aspiration was also compared. Results: The values of ETCO2, TV, RR and PIP during pneumoperitoneum were comparable between the two groups. Although PaCO2 at 2 h after induction was higher in patients with LMA (40.5 vs. 38.5 mmHg, p < 0.001), the pH and PFR values of the two groups were comparable. The incidence of PPC was not different. Conclusion: During prolonged laparoscopic abdominal surgery, the second-generation LMA facilitates adequate intraoperative gas exchange and represents an alternative to ETT.

Feasıbılıty of Transcutaneous Method for Carbon Dıoxıde Monıtorıng in an Intensive Care Unıt

2022 ◽  
Vol 18 ◽  
Author(s):  
Nazlıhan Boyacı ◽  
Sariyya Mammadova ◽  
Nurgül Naurizbay ◽  
Merve Güleryüz ◽  
Kamil İnci ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Intensive Care Unit ◽  
Intensive Care ◽  
Partial Pressure ◽  
Blood Gas ◽  
Peripheral Oxygen Saturation ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Randomized Controlled Studies ◽  
Significant Difference

Background: Transcutaneous partial pressure of carbon dioxide (PtCO2) monitorization provides a continuous and non-invasive measurement of partial pressure of carbon dioxide (pCO2). In addition, peripheral oxygen saturation (SpO2) can also be measured and followed by this method. However, data regarding the correlation between PtCO2 and arterial pCO2 (PaCO2) measurements acquired from peripheric arterial blood gas is controversial. Objective: We aimed to determine the reliability of PtCO2 with PaCO2 based on its advantages, like non-invasiveness and continuous applicability. Methods: Thirty-five adult patients with hypercapnic respiratory failure admitted to our tertiary medical intensive care unit (ICU) were included. Then we compared PtCO2 and PaCO2 and both SpO2 measurements simultaneously. Thirty measurements from the deltoid zone and 26 measurements from the cheek zone were applied. Results: PtCO2 could not be measured from the deltoid region in 5 (14%) patients. SpO2 and pulse rate could not be detected at 8 (26.7%) of the deltoid zone measurements. Correlation coefficients between PtCO2 and PaCO2 from deltoid and the cheek region were r: 0,915 and r: 0,946 (p = 0,0001). In comparison with the Bland-Altman test, difference in deltoid measurements was -1,38 ± 1,18 mmHg (p = 0.252) and in cheek measurements it was -5,12 ± 0,92 mmHg (p = 0,0001). There was no statistically significant difference between SpO2 measurements in each region. Conclusion: Our results suggest that PtCO2 and SpO2 measurements from the deltoid region are reliable compared to the arterial blood gas analysis in hypercapnic ICU patients. More randomized controlled studies investigating the effects of different measurement areas, hemodynamic parameters, and hemoglobin levels are needed.

GAS EXCHANGES AND BLOOD GAS CONCENTRATIONS IN THE FORG RANA RIDIBUNDA

1974 ◽  
Vol 60 (3) ◽  
pp. 901-908
Author(s):  
M. G. EMíLIO
Keyword(s):  
Carbon Dioxide ◽  
Partial Pressure ◽  
Ph Value ◽  
Total Concentration ◽  
Blood Gas ◽  
Gas Exchanges ◽  
Arterial Blood ◽  
Low Levels ◽  
Time Courses ◽  
Metabolic Carbon

1. The respiratory exchanges through the lungs and skin of frogs and the time courses of blood gas concentrations were studied during emergence and diving periods. 2. Most of the total oxygen uptake is carried out through the lungs. The partial pressure of oxygen in arterial blood falls to very low levels a few minutes after diving, showing that the cutaneous respiratory surface cannot compensate for the lack of lung respiration. 3. Most of the metabolic carbon dioxide is disposed of through the skin. Although the skin output is maintained through diving periods, there is an important rise in the partial pressure of carbon dioxide in blood following submergence. However, the total concentration of CO2 in the blood decreases, as does the blood pH value. 4. This phenomenon is probably the result of a metabolic acidosis due to the switching on of anaerobic processes during diving periods.

Gas Exchange

2017 ◽  
Author(s):  
John W. Kreit
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Partial Pressure ◽  
Capillary Blood ◽  
Pressure Gradients ◽  
Arterial Blood ◽  
Pulmonary Capillary ◽  
Partial Pressures ◽  
Pulmonary Capillary Blood ◽  
And Diffusion

Gas Exchange explains how four processes—delivery of oxygen, excretion of carbon dioxide, matching of ventilation and perfusion, and diffusion—allow the respiratory system to maintain normal partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) in the arterial blood. Partial pressure is important because O2 and CO2 molecules diffuse between alveolar gas and pulmonary capillary blood and between systemic capillary blood and the tissues along their partial pressure gradients, and diffusion continues until the partial pressures are equal. Ventilation is an essential part of gas exchange because it delivers O2, eliminates CO2, and determines ventilation–perfusion ratios. This chapter also explains how and why abnormalities in each of these processes may reduce PaO2, increase PaCO2, or both.

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