Background Extubation failure-associated factors haven't been investigated in elderly patients. We hypothesized that psoas cross-sectional area, an emerging indicator of frailty, can be a predictor of extubation outcomes.
Methods This retrospective study analyzed data from patients admitted between January and April 2016 at the intensive care unit (ICU) of the Tokyo Medical University Hospital. Patients were considered eligible if aged ≥65 years, required intubation at the emergency room, and were admitted to ICU for <24 h. Overall, 39 ICU patients were eligible and categorized into two groups: extubation success (n = 24) and extubation failure (n = 15) groups. The psoas cross-sectional area was measured at the third lumbar level on computer tomography images. Regions of interest were drawn freehand to outline the left and right psoas by an emergency physician. The average left and right psoas cross-sectional areas, used as the patient’s psoas cross-sectional area, were calculated. Psoas Muscle Index (PMI) was defined as the psoas cross-sectional area/height 2 . Primary outcome was to evaluate differences between the psoas cross-sectional area and f(PMI) between the groups, if any. Secondary outcome was to derive cut-off values using ROC curves.
Results Both groups were comparable in terms of demographic characteristics. Psoas cross-sectional area (success group, 1776.5 ± 498.2 mm 2 , failure group, 1391.2 ± 589.4 mm 2 ; p = 0.022) and PMI (success group, 1089 ± 270.7 mm 2 /m 2 , failure group, 889 ± 338.5 mm 2 /m 2 ; p = 0.032) were significantly greater in the success group than in the failure group. ROC curve of the psoas cross-sectional area and PMI were used to calculate sensitivity and speciﬁcity. ROC AUC was 0.74 for psoas cross-sectional area, and at a cut-off of 1260 points, the sensitivity, speciﬁcity, and positive and negative predictive values were 95.8%, 60.0%, 79.3%, and 90.0%, respectively. ROC AUC for PMI was 0.73, and at a cut-off of 812 points, the sensitivity, speciﬁcity, and positive and negative predictive values were 95.8%, 46.7%, 74.2%, and 87.5%, respectively.
Conclusions The psoas cross-sectional area and PMI can predict extubation outcomes in elderly intensive care patients.