Effect of ventilation on acid-base balance and oxygenation in low blood-flow states

Idris, Ahamed H.; Staples, Edward D.; Oʼbrien, Daniel J.; Melker, Richard J.; Rush, William; Duca, Kevin D. Del; Falk, Jay L.

doi:10.1097/00003246-199411000-00019

Cited by 12 publications

(18 citation statements)

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“…Situations of lowered cardiac output have been shown to exhibit increased A-V difference in CO 2 [ 41 - 43 ] as well as increased venous PCO 2 [ 41 , 42 ] due to a combination of arterial hypocapnia and venous hypercapnia. This is a result of slower blood flow causing accumulation of CO 2 [ 44 ]. Reduced cardiac output causes a state of hypoperfusion, lowering O 2 delivery to tissue demonstrated by PO 2 and SO 2 reduction.…”

Section: Resultsmentioning

confidence: 99%

Using a human cardiovascular-respiratory model to characterize cardiac tamponade and pulsus paradoxus

Ramachandran

Luo

Tony

et al. 2009

Theor Biol Med Model

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Background: Cardiac tamponade is a condition whereby fluid accumulation in the pericardial sac surrounding the heart causes elevation and equilibration of pericardial and cardiac chamber pressures, reduced cardiac output, changes in hemodynamics, partial chamber collapse, pulsus paradoxus, and arterio-venous acid-base disparity. Our large-scale model of the human cardiovascular-respiratory system (H-CRS) is employed to study mechanisms underlying cardiac tamponade and pulsus paradoxus. The model integrates hemodynamics, whole-body gas exchange, and autonomic nervous system control to simulate pressure, volume, and blood flow.

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Section: Resultsmentioning

confidence: 99%

Using a human cardiovascular-respiratory model to characterize cardiac tamponade and pulsus paradoxus

Ramachandran

Luo

Tony

et al. 2009

Theor Biol Med Model

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“…A sudden, large rise of EtCO 2 occurs at ROSC (LOE 3 and 6) , . Although EtCO 2 is also affected by ventilation parameters, the linear relationship of EtCO 2 and cardiac output was consistently observed in porcine CPA models (LOE 6) , . This has also been demonstrated in a number of human case studies (LOE 6), in which EtCO 2 also inversely correlated to systemic oxygen extraction ratio, which served as an indicator of tissue oxygen delivery , .…”

Section: Summary Of the Evidencementioning

confidence: 66%

RECOVER evidence and knowledge gap analysis on veterinary CPR. Part 5: Monitoring

Brainard

Boller

Fletcher

2012

J Vet Emergen Crit Care

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Objective -To systematically examine the evidence on patient monitoring before, during, and following veterinary CPR and to identify scientific knowledge gaps. Design -Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence and quality, and development of consensus on conclusions for application of the concepts to clinical practice. Relevant questions were answered on a worksheet template and reviewed by the Reassessment Campaign on Veterinary Resuscitation (RECOVER) monitoring domain members, by the RECOVER committee and opened for comments by veterinary professionals for 3 months. Setting -Academia, referral practice, and general practice. Results -Eighteen worksheets evaluated monitoring practices relevant for diagnosing cardiopulmonary arrest (CPA), monitoring CPR efforts, identifying return of spontaneous circulation (ROSC), and post-ROSC monitoring. Conclusions -Although veterinary clinical trials are lacking, experimental literature using canine models and human clinical trials provided relevant data. The major conclusions from this analysis of the literature highlight the utility of end-tidal carbon dioxide (EtCO 2 ) monitoring to identify ROSC and possibly to evaluate quality of CPR. In addition, recommendations for ECG analysis during CPR were addressed. Unless the patient is instrumented at the time of CPA, other monitoring devices (eg, Doppler flow probe) are likely not useful for diagnosis of CPA, and the possibility of pulseless electrical activity makes ECG inappropriate as a sole diagnostic tool. Optimal monitoring of the intra-and postcardiac arrest patient remains to be determined in clinical veterinary medicine, and further evaluation of the prognostic and prescriptive utility of EtCO 2 monitoring will provide material for future studies in veterinary CPR. Crit Care 2012; 22(S1): 65-84) (J Vet Emerg

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“…Regarding the MV as a powerful determinant of the PaCO 2 level [16,17], we included weight-corrected MV in the multivariable regression analysis. Nevertheless, weight-corrected MV did not predict intraoperative hypocapnia in neurosurgical patients.…”

Section: Discussionmentioning

confidence: 99%

Risk Factors for Intraoperative Hypocapnia in Pediatric Neurosurgical Patients: A Retrospective Cohort Study

et al. 2018

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Background: Hypocapnia has been associated with an increased risk and adverse outcomes in the injured brain. This study aimed to identify risk factors of intraoperative hypocapnia in pediatric neurosurgical patients when tidal volumes and respiratory rates were determined based on their weight and age, respectively. Methods: Electronic medical records of pediatric patients (≤18 years) who underwent neurosurgery from December 2014 to January 2016 were retrospectively reviewed. Minute ventilation was fixed according to each patient's weight and age. Hypocapnia was defined as arterial partial pressure of carbon dioxide <35 mm Hg from intraoperative arterial blood gas analysis. Patients were divided into hypocapnia and nonhypocapnia groups. Risk factors for intraoperative hypocapnia were found using univariable and multivariable logistic regression analyses. Results: Of the 333 pediatric patients analyzed, 101 (30%) and 232 (70%) were included in the hypocapnia and nonhypocapnia groups, respectively. There was no difference in the minute ventilation between the two groups. The hypocapnia group had more patients taking valproate (8.9 vs. 2.2%; p = 0.008; OR, 4.441; 95% CI, 1.449-13.61) and carbonic anhydrase inhibitors (7.9 vs. 2.2%; p = 0.018; OR, 3.905; 95% CI, 1.245-12.25). An operation for hydrocephalus was more commonly performed in the hypocapnia group (26.7 vs. 15.9%; p = 0.017; OR, 1.923; 95% CI, 1.094-3.379). In the multivariable regression analysis, valproate (OR, 3.939; 95% CI, 1.250-12.41; p = 0.019), carbonic anhydrase inhibitor (OR, 3.345; 95% CI, 1.029-10.88; p = 0.045), and operation for hydrocephalus (OR, 1.838; 95% CI, 1.032-3.272; p = 0.039) were independent risk factors for intraoperative hypocapnia. Conclusions: Pediatric patients taking valproate and carbonic anhydrase inhibitors and who were scheduled for surgery of hydrocephalus were at risk of developing intraoperative hypocapnia during neurosurgery, a finding warning the surgeon that a conventional ventilatory strategy would endanger these patients.

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Effect of ventilation on acid-base balance and oxygenation in low blood-flow states

Cited by 12 publications

References 0 publications

Using a human cardiovascular-respiratory model to characterize cardiac tamponade and pulsus paradoxus

Using a human cardiovascular-respiratory model to characterize cardiac tamponade and pulsus paradoxus

RECOVER evidence and knowledge gap analysis on veterinary CPR. Part 5: Monitoring

Risk Factors for Intraoperative Hypocapnia in Pediatric Neurosurgical Patients: A Retrospective Cohort Study

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