Critical care clinics
-
Critical care clinics · Jul 2008
ReviewDiagnosis and management of obesity hypoventilation syndrome in the ICU.
Obesity hypoventilation syndrome (OHS) is characterized by obesity, daytime hypercapnia, and sleep-disordered breathing in the absence of other known causes of hypercapnia. Because of the global obesity epidemic and the high prevalence of obstructive sleep apnea in the general population, critical care physicians are likely to encounter patients who have acute-on-chronic respiratory failure attributable to OHS in their clinical practice. In this article we define the clinical characteristics of OHS, review its pathophysiology, and discuss the morbidity and mortality associated with OHS. Finally, we offer treatment strategies during ICU management using noninvasive positive pressure ventilation that may guide the physician in the care of these challenging patients.
-
Critical care clinics · Jul 2008
ReviewThe overlap syndrome: chronic obstructive pulmonary disease and obstructive sleep apnea.
The overlap syndrome defines the relationship between obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD), and is a commonly noted but poorly studied disorder. Individuals who have the overlap syndrome have been recognized to have greater risk for pulmonary hypertension, right heart failure, and hypercapnia than patients who have either disorder alone. ⋯ The interaction between these two diseases is unclear, however. Further clinical trials of the overlap syndrome are urgently needed.
-
Intensive care subjects the critically ill patient to a multitude of stressors caused by the severity of illness and the use of invasive treatment modalities and medications. The ICU environment contributes significant stress of its own related to noise, light, 24-hour patient care, and other factors that disturb sleep. ⋯ Some sleep disorder symptomatology may be confused with serious neurologic complications of critical illness and lead to inappropriate testing or treatment, particularly in the patient who has narcolepsy. Given the high prevalence of sleep disorders in the general population, it is essential that the ICU practitioner attain an adequate knowledge of sleep and its disorders.
-
Achieving restorative sleep in the ICU remains a challenge for most patients. Various environmental and nonenvironmental factors affect sleep patterns in the ICU. This article discusses the effects and relative importance of these factors on sleep patterns in the critical care setting. In addition, the implications of sleep pattern alteration on human physiology and homeostatic mechanisms are considered.
-
Critical care clinics · Jul 2008
Common sleep problems in ICU: heart failure and sleep-disordered breathing syndromes.
Ventilation during sleep is under tight metabolic control, and can be destabilized by upper airway obstruction leading to snoring or obstructive apneas, inadequate respiratory pump muscle activity leading to hypoventilation, and central control instability leading to changes in metabolic feedback and loop gain. These three physiologic disturbances can lead to obstructive sleep apnea hypopnea syndrome (OSAHS), hypoventilation syndromes, and periodic breathing. OSAHS places a strain on the cardiac output by virtue of hypoxemia, large negative intrathoracic pressures, and high swings in systemic blood pressure. Periodic breathing, also known as central sleep apnea with Cheyne-Stokes pattern of respiration, is likely to be a product of advanced heart failure.