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Updated: Aug 12, 2026
08:22
In vitro Assessment of Myocardial Protection following Hypothermia-Preconditioning in a Human Cardiac Myocytes Model
Published on: October 27, 2020
The hydroxyl-hydrogen ion concentration ratio during hypothermia
Surgery, Gynecology & Obstetrics
|December 1, 1982
Summary
Temperature changes affect acid-base balance in vertebrates. Physicochemical constants maintain relative alkalinity and protein charge state in vitro, while in vivo regulation adjusts ventilation to maintain constant carbon dioxide content across temperatures.
Area of Science:
- Physiological chemistry
- Comparative physiology
- Biophysics
Background:
- Vertebrate extracellular and intracellular fluid acid-base balance is temperature-dependent.
- Key physicochemical factors include water dissociation, CO2 solubility, histidine imidazole dissociation, hydroxyl-hydrogen ion ratio, and protein charge.
- Understanding these factors is crucial for interpreting acid-base status across different temperatures.
Purpose of the Study:
- To review fundamental physicochemical characteristics of acid-base constituents in vertebrate fluids.
- To emphasize the impact of temperature on these characteristics.
- To explore implications for acid-base regulation in both poikilotherms and homeotherms.
Main Methods:
- Review of existing literature on physicochemical properties.
- Analysis of the interplay between temperature, dissociation constants, and gas solubility.
- Comparison of in vitro and in vivo acid-base responses.
- Examination of regulatory mechanisms in poikilotherms and humans under hypothermia.
Main Results:
- In vitro, the hydroxyl-hydrogen ion ratio and alpha-imidazole value remain constant with temperature changes due to parallel shifts in pN and pKIm and maintained CO2 content.
- In vivo, poikilotherms regulate PCO2 by adjusting ventilation (VA/VCO2) at different temperatures.
- Suppressed ventilatory and renal mechanisms in hypothermic humans mimic poikilotherm responses.
Conclusions:
- Acid-base status changes with temperature are governed by physical constants.
- In vivo regulation in poikilotherms ensures constant CO2 content.
- Clinical management of hypothermia requires controlled ventilation and pH monitoring.
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