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Table 7 Effect estimates from the model of length of stay in the CMP unit (n = 1225)

From: Case mix, outcome and activity for obstetric admissions to adult, general critical care units: a secondary analysis of the ICNARC Case Mix Programme Database

Variable Multiplicative effect on LOS (95% CI) P
Type of condition*   
   Haemorrhage 1.00 <0.001
   Hypertensive 1.44 (1.29–1.61)  
Age (per 10-year increase) 1.06 (0.98–1.14) 0.165
Surgical status*   
   Surgical (admission from theatre) 1.00 0.036
   Nonsurgical 1.12 (1.01–1.24)  
Past medical history presenta 1.04 (0.65–1.64) 0.883
Highest temperature (per 1°C increase)* 1.13 (1.06–1.20) <0.001
SBP (per 10 mmHg deviation from normal)* 1.09 (1.05–1.13) <0.001
Highest heart rate (per 10 beats/min increase)* 1.09 (1.06–1.12) <0.001
Highest respiratory rate (per 10 breaths/min) increase 0.98 (0.91–1.06) 0.664
PaO2/FiO2 ratio (per 100 mmHg decrease)* 1.14 (1.09–1.19) <0.001
Lowest pH (per 0.1 decrease)* 1.14 (1.06–1.23) <0.001
Lowest sodium (per 5 mmol/l decrease)* 0.90 (0.84–0.97) 0.006
Potassium (per 1 mmol/l deviation from normal) 1.12 (0.94–1.33) 0.190
Highest creatinine (per 100 μmol/l increase)* 1.32 (1.20–1.45) <0.001
Highest urea (per 5 mmol/l increase) 1.02 (0.94–1.11) 0.662
Lowest WBC (per 5 × 109/l decrease)* 1.12 (1.06–1.17) <0.001
Lowest platelet count (per 50 × 109/l decrease) 1.01 (0.97–1.05) 0.563
GCS (per 1 point decrease) 1.01 (0.99–1.03) 0.370
  1. aEvidence of any of a pre-specified list of severe conditions in the past medical history as defined in Acute Physiology and Chronic Health Evaluation (APACHE) II. CI, confidence interval; CPM, Case Mix Programme; GCS, Glasgow Coma Scale; LOS, length of stay; PaO2/FiO2, arterial oxygen tension; fractional inspired oxygen; SBP, systolic blood pressure; WBC, white blood count. *P < 0.05.