Modifications of tissular oxygenation and systemic hemodynamics after the correction of hypocapnia induced by mechanical ventilation.
The modifications of systemic hemodynamics, oxygen transport and tissular oxygenation in mechanically-ventilated critical ARF (acute respiratory failure) patients, after the correction of its hypocapnia by addition of dead space (VD) are determined. The prospective and randomized study was carried out in a multidisciplinary ICU. Fifteen ARF patients were studied within the first 48 hours of evolution. All the patients were intubated and mechanically ventilated. Three stages were delimited: I) 30 min after the beginning of anesthesia; II) 30 min after adding 30 cm of VD; III) 30 min after replacing the previous VD with a VD of 60 cm. Similar steady states had been reached when the measurements were taken. Ventilation parameters and FiO2 were kept stable. In stage I the patients presented a pure respiratory alkalosis and, with respect to hemodynamics, a hyperdynamic situation. In stage II the acid-base balance was normalized with a continuation of the hyperdynamic situation and an increase in mixed venous oxygen tension and saturation (PvO2 and SvO2) (p < 0.001). Stage III was characterized by a pure hypercapnic acidosis and an increase in capillary wedge pressure (CWP) (p < 0.05), right atrial pressure (RAP) (p < 0.001) and cardiac output (Qt) (p < 0.001); simultaneously, the systemic vascular resistances (SVR) decreased (p < 0.01), the PvO2, SvO2 and oxygen delivery (DO2) increased (p < 0.001); oxygen utilization coefficient (OUC) decreased (p < 0.01). The results suggest that the variations in PvO2 and SvO2 are a direct consequence of the modifications in blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)
Boix
J H
JH
UCI, Hospital Gran Vía, Castellón, Spain.
Marin
J
J
Enrique
E
E
Monferrer
J
J
Bataller
A
A
Servera
E
E
D000208:Acute Disease; D000328:Adult; D000368:Aged; D005260:Female; D006439:Hemodynamics; D006801:Humans; D016857:Hypocapnia / Q000209:etiology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D010313:Partial Pressure; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000009:adverse effects*; D012126:Respiratory Dead Space; D012131:Respiratory Insufficiency / Q000097:blood / Q000628:therapy; D014655:Vascular Resistance
D010100:Oxygen