RESUMO
Objective Heart failure (HF) is associated with intermittent hypoxia, and the effects of this hypoxia on the cardiovascular system are not well understood. This study was performed to compare the effects of acute hypoxia (10% oxygen) between patients with and without HF. Methods Fourteen patients with chronic HF and 17 matched control subjects were enrolled. Carotid artery changes were examined during the first period of hypoxia, and brachial artery changes were examined during the second period of hypoxia. Data were collected at baseline and after 2 and 4 minutes of hypoxia. Norepinephrine, epinephrine, dopamine, and renin were measured at baseline and after 4 minutes hypoxia. Results The carotid blood flow, carotid systolic diameter, and carotid diastolic diameter increased and the carotid resistance decreased in patients with HF. Hypoxia did not change the carotid compliance, distensibility, brachial artery blood flow and diameter, or concentrations of sympathomimetic amines in patients with HF, but hypoxia increased the norepinephrine level in the control group. Hypoxia increased minute ventilation and decreased the oxygen saturation and end-tidal carbon dioxide concentration in both groups. Conclusion Hypoxia-induced changes in the carotid artery suggest an intensification of compensatory mechanisms for preservation of cerebral blood flow in patients with HF.
Assuntos
Artérias Carótidas/fisiopatologia , Circulação Cerebrovascular/fisiologia , Cérebro/irrigação sanguínea , Insuficiência Cardíaca/fisiopatologia , Hipóxia/fisiopatologia , Adulto , Idoso , Artéria Braquial/fisiopatologia , Cérebro/fisiopatologia , Feminino , Insuficiência Cardíaca/sangue , Insuficiência Cardíaca/complicações , Hemodinâmica , Humanos , Hipóxia/sangue , Hipóxia/etiologia , Masculino , Pessoa de Meia-Idade , Oxigênio/sangueRESUMO
OBJECTIVE: This case report describes an unusual presentation of right upper lobe atelectasis associated with refractory hypoxemia to conventional alveolar recruitment maneuvers in a patient soon after coronary artery bypass grafting surgery. METHOD: Case-report. RESULTS: The alveolar recruitment with PEEP = 40 cm H2O improved the patient's atelectasis and hypoxemia. CONCLUSION: In the present report, the unusual alveolar recruitment maneuver with PEEP 40 cm H2O showed to be safe and efficient to reverse refractory hypoxemia and uncommon atelectasis in a patient after cardiac surgery.