The Relation Between Cardiac Function and Cerebral Blood Flow in Stroke Patients. 1. Effect of CO ₂ Inhalation

Abstract

The effects of CO 2 inhalation were determined on 23 stroke patients with and without hypertension who underwent clinical, cardiohemodynamic, cerebral blood flow (hemispheric mean and regional), cerebral metabolic rate and cerebral angiographical studies. Cardiac output, heart rate, systemic and pulmonary arterial blood pressures and cardiac work rose in essentially all patients during CO 2 inhalation, and fell to below baseline levels in approximately half of the patients studied after CO 2 , inhalation was discontinued. Baseline cardiac output was normal in normotensive stroke patients without cardiac dysfunction, but was low in hypertensive stroke patients. A statistically significant increase in cerebral blood flow occurred during CO 2 , inhalation, with an observed decrease in cerebrovascular resistance. The percentage increase in cerebral blood flow exceeded the increase in cardiac output. Since hypercarbia causes a rise in systemic and pulmonary arterial blood pressure, CO 2 inhalation should be used cautiously in patients with systemic or pulmonary hypertension. The rise in cardiac work during CO 2 inhalation could jeopardize patients with coronary heart disease and those with heart failure. Following cessation of CO 2 inhalation, blood pressure and cardiac output may fall below baseline levels, with a risk of posthypercapnic fall in cerebral blood flow. Occasionally, cardiac arrhythmia occurs during or following CO 2 inhalation.

Influence of Hypo- and Hypercapnia on Internal Carotid Artery Blood Flow after Arterial Reconstruction

“…This was also found in normal subjects and in patients with emphysema when PaCO, was increased (Fishman et al, 1960) and in stroke patients during hypercapnia (Cooper et al, 1970;Mc-Henry et al, 1972). This was also found in normal subjects and in patients with emphysema when PaCO, was increased (Fishman et al, 1960) and in stroke patients during hypercapnia (Cooper et al, 1970;Mc-Henry et al, 1972).…”

Perception of Cabin Air Quality among Drivers and Passengers

“…CO 2 is a potent stimulus of cerebral vasodilation and blood flow [10,27]. Early symptoms include a sense of "air hunger" or dyspnea and increased respiration and headaches.…”

“…A higher CO 2 concentration produces heart palpitations, confusion, severe dyspnea, vomiting, disorientation and hypertension [10,28]. CO 2 is also considered a potent stimulus of pulmonary minute ventilation [27]. Due to a low pH in the blood (which means a high level of acid), the respiratory center in the brain stimulates the respiratory muscles that increase ventilation [8].…”

“…[37]. Although there are few studies conducted on vehicles regarding carbon dioxide [5][6][7], the laboratory studies and those conducted in schools or in spacecrafts highlight alterations of the attention capacities and decision-making and academic performances [8,9,[11][12][13]27].…”

Experimental middle cerebral artery microsurgical embolectomy

“…Potential therapy modalities include microsurgical embolectomy- Chou (1963), Ya~argil et al (1970), Piscal (1973, Jacobson et al (1962), and Khodadad (]973) or revascularization -Crowell etal. (1973), hypothermia, pressor agents- Browne (1969) corticoids, Patten et al (1971) hyperventilation- Soloway et al (1968), Cooper et al (1970) and barbiturates-Smith et al (1974), but there are no clinical or experimental guidelines as to their use and timing at present.…”