To remain healthy, the tissues in the human body require constant and adequate delivery of blood and oxygen, known as tissue perfusion and oxygenation. When tissues are deprived of oxygen—a condition termed “hypoperfusion”—tissue hypoxia occurs and, if unattended, will lead to organ failure.
In critically ill or injured patients, tissue perfusion and oxygenation are essential in maintaining organ vitality and limiting the risk of multiple organ dysfunction syndrome (MODS) resulting from tissue hypoxia.
Patients with early warnings of failing tissue perfusion have better chances of recovery when treatment can be started promptly.1.2 Clinicians need quick and reliable tools for prompt assessment and optimal management of perfusion.
Tissue pCO2—an abbreviation of “partial pressure of carbon dioxide”—indicates the amount of carbon dioxide gas dissolved in the blood. As an early indicator of tissue hypoperfusion, monitoring tissue pCO2 can provide life-saving information.
Splanchnic Circulation and Multiple Organ Dysfunction Syndrome (MODS)
Tissue hypoperfusion followed by hypercapnia appears early in splanchnic (visceral) circulation, even though hypoperfusion may not be readily apparent to the care provider. Without early detection of hypoperfusion, the patient’s risk of MODS increases.
From Hypoperfusion to Organ Failure
A cascade of physiologic events within the gastric mucosa can result in grave damage to body organs. When hypoperfusion compromises intestinal mucosa, ischemia and gastric hypercapnia follow. These two clinical states can spur release of bacteria and inflammatory substances into the splanchnic circulation, leading to sepsis, MODS, and even death.
Gastric Carbon Dioxide: An Early Marker of Organ Hypoperfusion
Fortunately, there is an early marker of potential hypoperfusion: elevated partial pressure of carbon dioxide (pCO2) in the tissues of the gastrointestinal system.
Elevated gastric pCO2 can signal hypoperfusion, ischemia, and development and progression of MODS-before other hemodynamic measurements identify patient decline.
ExoStat Medical has developed an easy-to-use device that measures pCO2 in oral mucosa. Studies have shown that oral mucosal pC02 correlates well with gastric pCO2 from tonometry.345 Unlike tonometry and blood lactate measurements, POMCO2 is simple, noninvasive, and quick to measure. Know on the spot whether a patient’s oral mucosal pCO2 is within normal limits.
Tissue Hypoperfusion and Hypercapnia
In a study of healthy subjects, the range of normal POMCO2 was 43.5-63.5 mmHg6 Patients with elevations above this range have been associated with poorer outcomes.7 Knowing POMCO2 may provide an early warning of tissue hypoxia and pending MODS in patients.
1 Gutierrez G, et ai.Lancet 1992; 339: 195-199.
2 Marik PE. Chest 1993; 104:225-229.
3 Marik PE. Chest 2001 ; 120:923-927.
4 Rackow E, et a l. Chest 2001; 120:1633-1638.
5 Povoas H, et al. Chest 2000; 118:11 27-1132.
6 From a study of 41 healthy volunteers, the normal value was a mean of 53.5 with a standard deviation of 5 mmHg. Two standard deviations about the mean yield a normal range of 43.5-63.5 mmHg. Data on file at ExoStat Medical.
7 Weil MH, et al. Crit Care Med 1999; 27:1225-1229.