Avtor/Urednik		Johnson, Bruce A; Weil, Max Harry; Tang, Wanchun; Noč, Marko; McKee, Dave; McCandless, David
Naslov		Mechanisms of myocardial hypercarbic acidosis during cardiac arrest
Tip		članek
Vir		J Appl Physiol
Vol. in št.		Letnik 78, št. 4
Leto izdaje		1995
Obseg		str. 1579-84
Jezik		eng
Abstrakt		During the global myocardial ischemia of cardiac arrest and during regional myocardial ischemia due to local impairment of coronary blood flow, intramyocardial carbon dioxide tensions (Pmco2) of ischemic myocardium increase to levels exceeding 400 Torr. The mechanism of such myocardial hypercarbic acidosis is as yet incompletely understood, specifically whether these increases in Pmco2 are due to increased oxidative metabolism, decreased CO2 removal, or buffering of metabolic acids. We therefore measured Pmco2 and the total CO2 content of rat hearts harvested before, during, and after resuscitation from cardiac arrest. Pmco2 significantly increased from an average of 63 to 209 Torr during a 4-min interval of untreated ventricular fibrillation. This was associated with concurrent decreases in intracellular pH from an average of 7.03 to 6.02 units. The total CO2 content of the myocardium simultaneously decreased from 17.0 to 16.5 mmol/kg. Accordingly, increases in Pmco2 and ŠH+Ć were observed in the absence of increases in the total CO2 content and therefore the calculated myocardial bicarbonate. These observations in the rat model implicate buffering of metabolic acids by bicarbonate rather than increases in CO2 production or decreases in CO2 removal as the predominant mechanism accounting for myocardial hypercarbia.
Deskriptorji		ACIDOSIS CARBON DIOXIDE HEART ARREST LACTATES MYOCARDIUM BLOOD FLOW VELOCITY CORONARY CIRCULATION DISEASE MODELS, ANIMAL HYDROGEN-ION CONCENTRATION HYPERBARIC OXYGENATION RATS RATS, SPRAGUE-DAWLEY