The primary analyses included all patients regardless of the reason for admission to the ICU. The secondary analyses excluded patients with hypotension, respiratory

inhibitor bulk failure or those who were intubated—conditions considered as strong indications for ICU admission. In the secondary analyses, the total hospital length of stay and ICU length of stay were analysed as continuous variables using Cox proportional hazard. Interval estimates of ORs for categories of the independent variable and identified covariates were generated. Effect measures were adjusted for the following covariates: Age. Gender. Charlson comorbidity index (CCI) based on a history of the following: acute myocardial infarction, congestive heart failure, peripheral vascular disease, cerebrovascular disease, dementia, chronic pulmonary disease, connective tissue disease, peptic ulcer disease, mild liver disease, moderate to severe liver disease, hemiplegia, moderate to severe renal disease, any tumour within the past 5 years, metastatic solid tumour, lymphoma, leukaemia, diabetes, diabetes with end organ damage and AIDS. Acute Physiology and Chronic Health Evaluation II (APACHE II) score on arrival at the MICU/HDU;

Recent (7 days) discharge from the hospital prior to current admission. Objective parameters on presentation at the ED including heart rate, respiratory rate, oxygen saturation, mean arterial pressure. Resuscitation efforts at the ED. Intubation at the ED. Admission at the MICU versus HDU. Results Baseline characteristics Table 1 presents the baseline characteristics of direct and indirect admissions. There were

706 patients admitted to the MICU/HDU within 24 h of presentation at the ED in 2009. Of these, more than two-thirds were admitted directly from the ED to the MICU/HDU with the rest having been admitted to the general wards before their subsequent transfer. Compared with indirect admissions, a significantly greater proportion of those directly admitted underwent resuscitation and intubation at the ED. However, those indirectly admitted were older, had more comorbidities and were significantly Batimastat more likely to be admitted to the MICU than the HDU. Time from ED presentation to MICU/HDU admission was more than four times longer for indirect admissions. Table 1 Baseline characteristics of patients directly and indirectly admitted to the ICU/MICU Clinical and laboratory findings of patients on arrival at the ED are presented in table 2. Aside from pneumonia, which was the most common diagnosis at the ED, chronic airway obstruction was among the five leading diagnoses for direct and indirect ICU admissions. Respiratory distress was the most common reason for admission to the ICU. Intubation, hypotension and severe acidosis were other common reasons for admission to the ICU for directly and indirectly admitted patients.