Relative-assessed psychological factors predict sedation requirement in critically ill patients.
OBJECTIVE
Sedation is frequently required in critically ill, mechanically ventilated patients. Sedation and analgesia requirements may vary substantially among patients. This study examined whether psychological factors predict amount of sedation requirements beyond the effects of other biomedical parameters.


METHODS
This study used a prospective correlative design in an eight-bed medical intensive care unit at a tertiary university hospital. Fifty-five adult patients requiring mechanical ventilation were included. We evaluated by questionnaires three psychological factors of patients--hostility, anxiety and desire for control (DC)--as completed by patients' relatives at entry to the intensive care unit. Daily doses of sedatives required were monitored. The primary outcome measurement was midazolam dose expressed in mg/kg/h.


RESULTS
There was a statistically significant correlation between psychological factors and midazolam dose (mg/kg/h): r values = 0.40 for anxiety, 0.43 for hostility, and 0.46 for DC. Age and pulmonary edema were inversely related to midazolam requirements, whereas smoking, chronic obstructive pulmonary disease, fentanyl dose, and therapeutic intervention scoring system were positively correlated with midazolam doses. In a multiple regression, DC accounted for an additional and significant 5.4% of the variance in midazolam after controlling statistically for the effects of the significant background and biomedical predictors. In the final regression equation, DC and fentanyl were the only significant factors associated with higher sedation requirement.


CONCLUSIONS
Premorbid psychological profile independently predicts sedation requirement in critically ill, mechanically ventilated patients. Early identification of such a profile may help in sedation management and patient care. The possible mechanisms and clinical implications are discussed.
Green
Tamar
T
Medical Intensive Care Unit, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University, Beer Sheva, Israel.
Gidron
Yori
Y
Friger
Michael
M
Almog
Yaniv
Y
D018806:APACHE; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000786:Anger; D017028:Caregivers / Q000523:psychology*; D016638:Critical Illness / Q000523:psychology* / Q000628:therapy*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage / Q000627:therapeutic use; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage* / Q000627:therapeutic use; D007362:Intensive Care Units; D007389:Internal-External Control; D008297:Male; D008874:Midazolam / Q000008:administration & dosage* / Q000627:therapeutic use; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000523:psychology / Q000628:therapy; D012121:Respiration, Artificial; D011795:Surveys and Questionnaires
D006993:Hypnotics and Sedatives; D008874:Midazolam; D005283:Fentanyl