Sleep in Critically III Chemically Paralyzed Patients Requiring Mechanical Ventilation: Severity of Illness
A nonsignificant trend (p = 0.07) of increasing severity of illness (APACHE II), greatest in the CS/NMBA group relative to the IS group, was noted. The LIS was significantly higher in the CS and CS/NMBA groups (p < 0.001) than in the IS group. The LIS in the CS/NMBA group was 50% greater than in the CS group (p < 0.016; Table 1). There was no significant difference between the groups regarding length of stay in the ICU prior to the day of study, and no correlation existed between length of stay and sleep data. Use of vasopressor drugs was greatest in the CS/NMBA group, of whom 50% required hemodynamic support.
Mode of mechanical ventilation varied between the groups. None of our patients were receiving assist-control ventilation. Pressure support (PS) ventilation was used throughout the entire 24-h period in only 2 of the 18 patients: 1 patient in the IS group and 1 patient in the CS group. comments
Volume control using synchronized intermittent mandatory ventilation (SIMV) was used in five patients in the IS group (of whom four were changed during the 24 period to PS mode), four patients in the CS group, and three patients in the CS/NMBA group. Pressure control/ intermittent mandatory ventilation (IMV) mode was used in three patients in the CS/NMBA group and one patient in the CS group. Patients receiving pressure control ventilation required vasopressor therapy and had higher APACHE II scores.
Blood cultures were obtained in 17 patients (none in the patient with amyotrophic lateral sclerosis), but results were positive (fungus) in only 1 patient. Tracheal aspirate or BAL findings were positive in seven patients, and open lung biopsy was positive in one patient. Total positive culture results were distributed among the groups as follows: three patients, five patients, and one patient in the IS, CS, and CS/NMBA groups, respectively. Total bilirubin was elevated in one patient in the IS group (3.2 mg/dL) and one patient (3.4 mg/dL) in the CS/NMBA group (data not shown). Renal insufficiency, defined as a serum creatinine level > 2 mg/dL, was present in three patients receiving IS and in only one patient (2.2 mg/dL) in the CS group.
Category: Respiratory Symptoms
Tags: ICU, mechanical ventilation, polysomnography, sleep