Relationship between cardiac output and the end-trial carbon dioxide tension

doi:10.1016/S0196-0644(05)81512-4

Annals of Emergency Medicine

Volume 19, Issue 10, October 1990, Pages 1104-1106

https://doi.org/10.1016/S0196-0644(05)81512-4 Get rights and content

Study objective:

To further define the relationship between cardiac output (CO) and end-tidal carbon dioxide tension (ETCO₂) at various levels of systemic flow.

Design:

Prospective, controlled laboratory investigation.

Setting:

Animal laboratory.

Type of participants:

Fourteen anesthetized, intubated sheep weighing 23 to 47 kg.

Interventions:

One hundred seventy-two simultaneous measurements of thermodilution CO and ETCO₂ were made during controlled arterial hemorrhage. After a 30-minute baseline control period, CO was sampled from approximately 0.6 to more than 8.0 L/min during a 60- to 90-minute period of controlled hemorrhage.

Measurements:

Thermodilution CO; arterial pressure using fluid-filled plastic 14-gauge catheters; ETCO₂ using an infrared analyzer.

Main results:

A plot of CO versus ETCO₂ suggested that the relationship was logarithmic rather than linear. Linear regression showed that ETCO₂ was significantly related (r = .91; P < .001) to a logarithmic transformation of the CO.

Conclusions:

The relationship between CO and ETCO₂ is logarithmic. Decreased presentation of CO₂ to the lungs is the major, rate-limiting determinant of the ETCO₂ during low flow. As the CO increases during resuscitation from shock or cardiac arrest, respiration becomes the rate-limiting controller of the ETCO₂ (after the tissue washout of CO₂ has occured). Under such conditions, the ETCO₂ provides useful information about the adequacy of ventilation provided that there is little ventilation/perfusion mismatch.

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Cited by (137)

Wolf Creek XVII Part 6: Physiology-Guided CPR
2024, Resuscitation Plus
Physiology-guided cardiopulmonary resuscitation (CPR) offers the potential to optimize resuscitation and enable early prognosis.
Physiology-Guided CPR was one of six focus topic for the Wolf Creek XVII Conference held on June 14–17, 2023 in Ann Arbor, Michigan, USA. International thought leaders and scientists in the field of cardiac arrest resuscitation from academia and industry were invited. Participants submitted via online survey knowledge gaps, barriers to translation and research priorities for each focus topic. Expert panels used the survey results and their own perspectives and insights to create and present a preliminary unranked list for each category, which was then debated, revised and ranked by all attendees to identify the top 5 for each category.
Top knowledge gaps include identifying optimal strategies for the evaluation of physiology-guided CPR and the optimal values for existing patients using patient outcomes. The main barriers to translation are the limited usability outside of critical care environments and the training and equipment required for monitoring. The top research priorities are the development of clinically feasible and reliable methods to continuously and non-invasively monitor physiology during CPR and prospective human studies proving targeting parameters during CPR improves outcomes.
Physiology-guided CPR has the potential to provide individualized resuscitation and move away from a one-size-fits-all approach. Current understanding is limited, and clinical trials are lacking. Future developments need to consider the clinical application and applicability of measurement to all healthcare settings. Therefore, clinical trials using physiology-guided CPR for individualisation of resuscitation efforts are needed.
End-tidal carbon dioxide after sodium bicarbonate infusion during mechanical ventilation or ongoing cardiopulmonary resuscitation
2024, American Journal of Emergency Medicine
End-tidal CO₂ is used to monitor the ventilation status or hemodynamic efficacy during mechanical ventilation or cardiopulmonary resuscitation (CPR), and it may be affected by various factors including sodium bicarbonate administration. This study investigated changes in end-tidal CO2 after sodium bicarbonate administration.
This single-center, prospective observational study included adult patients who received sodium bicarbonate during mechanical ventilation or CPR. End-tidal CO₂ elevation was defined as an increase of ≥20% from the baseline end-tidal CO₂ value. The time to initial increase (lag time, T_lag), time to peak (T_peak), and duration of the end-tidal CO₂ rise (T_duration) were compared between the patients with spontaneous circulation (SC group) and those with ongoing resuscitation (CPR group).
Thirty-three patients, (SC group, n = 25; CPR group, n = 8), were included. Compared with the baseline value, the median values of peak end-tidal CO₂ after sodium bicarbonate injection increased by 100% (from 21 to 41 mmHg) in all patients, 89.5% (from 21 to 39 mmHg) in the SC group, and 160.2% (from 15 to 41 mmHg) in the CPR group. The median T_lag was 17 s (IQR: 12–21) and the median T_peak was 35 s (IQR: 27–52). The median T_duration was 420 s (IQR: 90–639). The median T_lag, T_peak, and T_duration were not significantly different between the groups. T_duration was associated with the amount of sodium bicarbonate for SC group (correlation coefficient: 0.531, p = 0.006).
The administration of sodium bicarbonate may lead to a substantial increase in end-tidal CO₂ for several minutes in patients with spontaneous circulation and in patients with ongoing CPR. After intravenous administration of sodium bicarbonate, the use of end-tidal CO₂ pressure as a physiological indicator may be limited.
Capnography for Monitoring of the Critically Ill Patient
2022, Clinics in Chest Medicine
End-tidal carbon dioxide (ETCO<inf>2</inf>) and ventricular fibrillation amplitude spectral area (AMSA) for shock outcome prediction in out-of-hospital cardiac arrest. Are they two sides of the same coin?
2021, Resuscitation
Citation Excerpt :
Based on that there is the need for non–invasive parameters able to monitor the quality of CPR during resuscitation. End-tidal carbon dioxide (ETCO2), which provides a non-invasive assessment of coronary and myocardial perfusion during CPR, has been widely demonstrated to be directly related to the quality of CPR8–15 and its use is currently recommended by international guidelines.16,17 Moreover, our groups have recently shown that the values of ETCO2 before defibrillation predict the effectiveness of the shock.18,19
Ventricular fibrillation amplitude spectral area (AMSA) and end-tidal carbon dioxide (ETCO₂) are predictors of shock success, understood as restoration of an organized rhythm, and return of spontaneous circulation (ROSC). However, little is known about their combined use. We aimed to assess the prediction accuracy when combined, and to clarify if they are correlated in out of hospital cardiac arrest' victims.
Records acquired by external defibrillators in out-of-hospital cardiac arrest patients of the Lombardia Cardiac Arrest registry were processed. The 1-min pre-shock ETCO₂ median value (METCO₂) was computed from the capnogram and AMSA (2–48 mV.Hz range) computed applying the Fast Fourier Transform to a 2-second pre-shock filtered ECG interval (0.5−30 Hz). Support Vector Machine (SVM) predictive models based on METCO₂, AMSA and their combination were fit; results were given as the area under the curve (AUC) of the receiver operating characteristic (ROC) curves.
We considered 112 patients with 391 shocks delivered. METCO₂ and AMSA were predictors of shock success [AUC (IQR) of the ROC curve: 0.59 (0.56−0.62); 0.68 (0.65−0.72), respectively] and of ROSC [0.56 (0.53−0.59); 0.74 (0.71−0.78),]. Their combination in a SVM model increased the accuracy for predicting shock success [AUC (IQR) of the ROC curve: 0.71 (0.68−0.75)] and ROSC [0.77 (0.73−0.8)]. AMSA and METCO₂ were significantly correlated only in patients who achieved ROSC (rho = 0.33 p = 0.03).
AMSA and ETCO₂ predict shock success and ROSC after every shock, and their predictive power increases if combined. Notably, they were correlated only in patients who achieved ROSC.
Utility of changes in end-tidal carbon dioxide after volume expansion to assess fluid responsiveness in the operating room: a prospective observational study
2020, British Journal of Anaesthesia
From a physiological viewpoint, changes in end-tidal carbon dioxide (EtCO₂) could be a simple, noninvasive, and inexpensive way to monitor changes in cardiac index. This study aimed to assess the utility of changes in EtCO₂ as a marker of fluid responsiveness after volume expansion in the operating room.
A prospective observational study was conducted in a tertiary university teaching hospital, from August 2018 to February 2019. A total of 109 non-consecutive, mechanically ventilated adults undergoing neurosurgery in the supine position with cardiac output monitors were included. Patients with major respiratory disease, arrhythmia, or heart failure were excluded. Volume expansion with 250 ml of saline 0.9% was performed over 10 min to maximise cardiac output during surgery, according to current guidelines. A positive fluid challenge was defined as an increase in stroke volume index of more than 10% from baseline. Changes in stroke volume index (monitored using pulse contour analysis) and EtCO₂ were recorded before and after infusion.
A total of 242 fluid challenges in 114 patients were performed, of which 26.9% were positive. Changes in EtCO₂ > 1.1% induced by infusions had utility for identifying fluid responsiveness, with a sensitivity of 62.9% (95% confidence interval [CI], 62.5–63.3%) and a specificity of 77.8% (95% CI, 77.6–78.1%). The area under the receiver operating characteristic curve for changes in EtCO₂ after volume expansion was 0.683 (95% CI, 0.680–0.686).
Changes in EtCO₂ induced by rapid infusion of 250 ml saline 0.9% lacked accuracy for identifying fluid responsiveness in mechanically ventilated patients in the operating room.
NCT03635307.
Tracheal intubation in patients with cardiac arrest: Should we focus on success rate of intubation rather than the outcome of resuscitation?
2019, Resuscitation

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Laboratory investigationRelationship between cardiac output and the end-trial carbon dioxide tension

Study objective:

Design:

Setting:

Type of participants:

Interventions:

Measurements:

Main results:

Conclusions:

Resuscitation

Am J Emerg Med

J Am Coll Cardiol

Ann Emerg Med

Am J Cardiol

Cardiac output and end tidal carbon dioxide

Crit Care Med

The clinical value of end-tidal carbon dioxide monitoring during cardiopulmonary resuscitation

JAMA

Laboratory investigation
Relationship between cardiac output and the end-trial carbon dioxide tension