Clinics
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Review
Cheyne-Stokes respiration in patients with congestive heart failure: causes and consequences.
Cheyne-Stokes respiration is a form of periodic breathing in which central apneas and hypopneas alternate with periods of hyperventilation, producing a waxing and waning pattern of tidal volume. This review focuses on the causes and consequences of Cheyne-Stokes respiration in patients with congestive heart failure, in whom the prevalence is strikingly high and ranges from 30% to 50%. Several factors have been implicated in the genesis of Cheyne-Stokes respiration, including low cardiac output and recurrent hypoxia. ⋯ Hyperventilation is associated with pulmonary congestion, and Cheyne-Stokes respiration is more prone to occur during sleep, when the respiratory system is mainly dependent on chemical control. It is associated with recurrent dips in oxygen saturation and arousals from sleep, with oscillations in blood pressure and heart rate, sympathetic activation and increased risk of ventricular tachycardia. Cheyne-Stokes respiration is an independent marker of poor prognosis and may participate in a vicious cycle, further stressing the failing heart.
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Comparative Study
Is the Advanced Trauma Life Support simulation exam more stressful for the surgeon than emergency department trauma care?
Stress affects surgeons both during training and during professional activity. ⋯ Heart rate and systolic arterial pressure were increased at the beginning and at the end of Advanced Trauma Life Support simulation and emergency room initial care. Diastolic arterial pressure was only increased at the end of the Advanced Trauma Life Support simulation. Comparing values obtained during the Advanced Trauma Life Support simulation with those obtained during emergency room initial care, heart rate and systolic arterial pressure were significantly higher during the Advanced Trauma Life Support simulation both at the beginning and end of the test events. However, diastolic arterial pressure was only significantly higher for Advanced Trauma Life Support simulation compared emergency room at the end of the procedures. These results suggest that the simulation in the practical exam portion of the Advanced Trauma Life Support course is more stressful for the resident surgeon than is the actual initial assessment and care of trauma patients in an emergency room.
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To evaluate the effects of red blood cell transfusion in patients with SIRS/sepsis who presented hemoglobin levels under 9.0 g/dL at intensive care unit admission, using two parameters of organ perfusion: mixed venous oxygen saturation and serum lactate levels. ⋯ Twenty-nine patients (17 male, 12 female) with ages of 61.9 +/- 15.1 (mean +/- SD) years (range, 21-85 years) and a mean APACHE II score of 12.5 +/- 3.75 (7-21) were transfused with a mean of 1.41 packed red cell units. A significant increase in hemoglobin levels was reached by blood transfusion, from 8.14 +/- 0.64 g/dL (pre-T) to 9.4 +/- 0.33 g/dL (post-T), with P <.001. However, this was not accompanied by a significant change in lactate levels, from 1.87 +/- 1.22 mmol/l (pre-T) to 1.56 +/- 0.28 mmol/l (post-T), with P =.28, or in mixed venous oxygen saturation, from 64.3 +/- 8.52% (pre-T) to 67.4 +/- 6.74% (post-T), with P = .13. The results were similar even in patients with hemoglobin levels under 8.0 g/dL (n = 9). These results suggest that red blood cell transfusions, in spite of leading to a significant increase in hemoglobin levels, are not associated with an improvement in tissue oxygenation in patients with SIRS/sepsis and hemoglobin levels < 9 g/dL.