Related Experiment Video
Updated: Aug 11, 2026
07:51
Standardized Hemorrhagic Shock Induction Guided by Cerebral Oximetry and Extended Hemodynamic Monitoring in Pigs
Published on: May 21, 2019
End-tidal CO2 pressure determinants during hemorrhagic shock
A Dubin1, G Murias, E Estenssoro
1Cátedra de Farmacología, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Argentina. adee@infovia.com.ar
Intensive Care Medicine
|February 24, 2001
Summary
End-tidal CO2 (PETCO2) decreases significantly with reduced cardiac output (CO) during hemorrhagic shock. This drop in PETCO2 may indicate reduced CO2 production when oxygen delivery is insufficient.
Area of Science:
- Physiology
- Critical Care Medicine
- Cardiovascular Research
Background:
- Hemorrhagic shock significantly impacts cardiorespiratory function.
- End-tidal CO2 (PETCO2) is a non-invasive monitor reflecting ventilation, perfusion, and metabolism.
- Understanding PETCO2 dynamics in shock is crucial for patient management.
Purpose of the Study:
- To investigate the relationship between PETCO2 and its physiological determinants, cardiac output (CO) and carbon dioxide production (VCO2).
- To analyze these relationships in a canine model of hemorrhagic shock under controlled ventilation.
Main Methods:
- Prospective, observational study involving six mechanically ventilated dogs undergoing progressive hemorrhage.
- Continuous monitoring of PETCO2, pulmonary artery blood flow (CO), arterial oxygen saturation (SaO2), oxygen consumption (VO2), and VCO2.
- Calculation of oxygen delivery (DO2) and analysis of critical DO2 points.
Main Results:
- PETCO2 showed a strong logarithmic correlation with CO (median r2 = 0.90), with greater decreases at lower flow rates.
- PETCO2 exhibited a linear correlation with VCO2 (median r2 = 0.77).
- Critical DO2 for PETCO2 and VO2 were not significantly different.
Conclusions:
- The study confirms the strong relationship between PETCO2 and CO during hemorrhagic shock.
- The pronounced decrease in PETCO2 at low CO levels may reflect reduced CO2 production during oxygen supply dependency.
Related Concept Videos
01:17Assessment of Diffusion and Perfusion
Understanding and evaluating diffusion and perfusion is critical in assessing a patient's respiratory and circulatory health. These processes play key roles in maintaining the body's internal environment, ensuring that tissues receive adequate oxygen while waste products are efficiently removed.
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this principle...
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this principle...
01:17Measurement of Blood Pressure
Assessing blood pressure is a standard procedure executed in virtually all medical environments. The method utilized today was established over a hundred years ago by an innovative Russian doctor, Dr. Nikolai Korotkoff. The soft ticking noise, known as Korotkoff sounds, heard while taking blood pressure readings results from turbulent blood flow within the vessels. The apparatus required for this procedure includes a sphygmomanometer, a blood pressure cuff attached to a gauge, and a stethoscope.
01:24Blood Pressure Imbalances and Circulatory Shock
Disorders affecting blood volume, vascular tone, or vascular function can disrupt vascular homeostasis, including conditions like hypertension, hemorrhage, and shock.
Blood Pressure: Hypertension and Hypotension
Normal blood pressure is 120/80 mm Hg. Elevated blood pressure is 120-129/under 80 mm Hg. Hypertension, warranting treatment at 130/80 mm Hg, is often asymptomatic and can lead to severe cardiovascular events, aneurysms, peripheral arterial disease, chronic renal disease, or cardiac...
Blood Pressure: Hypertension and Hypotension
Normal blood pressure is 120/80 mm Hg. Elevated blood pressure is 120-129/under 80 mm Hg. Hypertension, warranting treatment at 130/80 mm Hg, is often asymptomatic and can lead to severe cardiovascular events, aneurysms, peripheral arterial disease, chronic renal disease, or cardiac...
01:31Chemical Factors Affecting Respiration Centers
Chemical factors such as changing CO2, O2, and H+ levels in arterial blood play a critical role in influencing respiration depth and rates. These variations are detected by chemoreceptors—specialized sensors located in two primary body areas. Central chemoreceptors are found throughout the brain stem, including the ventrolateral medulla, while peripheral chemoreceptors are located in the aortic arch and carotid arteries.
CO2 has a potent influence on respiration and is strictly regulated. Under...
CO2 has a potent influence on respiration and is strictly regulated. Under...
01:21Acute Respiratory Failure-II
Type I Respiratory Failure, or hypoxemic respiratory failure, occurs when the partial pressure of oxygen (PaO2) in arterial blood falls below 60 mmHg while breathing room air without a corresponding increase in arterial carbon dioxide levels (PaCO2). This condition highlights a significant impairment in the lungs' capacity to oxygenate the blood.
The underlying physiological abnormalities that contribute to hypoxemic respiratory failure include:
The underlying physiological abnormalities that contribute to hypoxemic respiratory failure include:
01:29Hemorrhagic Stroke ll: Pathophysiology
A hemorrhagic stroke develops when a cerebral blood vessel ruptures, allowing blood to escape into the surrounding brain tissue, as in intracerebral hemorrhage (ICH), or into the subarachnoid space, as in subarachnoid hemorrhage (SAH). Because the skull is a rigid compartment, the sudden presence of extravascular blood rapidly increases intracranial pressure and compresses adjacent neural structures, leading to immediate tissue injury and impaired cerebral perfusion.Mass Effect and Primary...