Factors associated with time to laparoscopic cholecystectomy for acute cholecystitis

Table 4 Hierarchical linear models for effect of pre-operative imaging studies on time to surgery

Model	Estimate mean (h)	Standard error	95% CI	P value4
Unadjusted				< 0.01
All studies done	125.0	36.8	51.4-198.6
US only	23.6	6.6	10.4-36.8
US and HIDA	25.2	15.0	0.0-55.2
CT only	37.0	11.7	13.7-60.3
CT and MRCP	192.0	36.8	118.4-265.6
CT and HIDA	59.2	15.0	29.1-89.2
CT and US	54.9	10.6	33.7-76.2
US, CT and HIDA	56.7	21.3	14.2-99.2
Adjusted for patient demographics1				< 0.01
All studies done	128.3	36.6	55.1-201.6
US only	24.7	6.6	11.4-38.0
US and HIDA	26.2	14.9	0.0-56.0
CT only	38.3	11.5	15.3-61.3
CT and MRCP	179.5	37.5	104.5-254.4
CT and HIDA	58.2	15.0	28.2-88.3
CT and US	52.4	10.6	31.3-73.5
US, CT and HIDA	53.9	21.8	10.3-97.4
Adjusted for demographics and co-morbidity				< 0.01
All studies done	130.6	35.4	59.9-201.4
US only	23.1	6.5	10.2-36.0
US and HIDA	29.7	14.4	0.9-58.6
CT only	39.4	11.1	17.1-61.6
CT and MRCP	169.6	36.4	96.8-242.5
CT and HIDA	58.0	14.5	29.0-87.0
CT and US	55.2	10.3	34.6-75.7
US, CT and HIDA	52.2	21.0	10.1-94.3
Adjusted for demographics, co-morbidity and physical signs2				< 0.01
All studies done	121.0	36.4	48.1-193.2
US only	20.4	6.5	7.5-33.3
US and HIDA	29.7	14.3	1.2-58.3
CT only	41.3	11.1	19.1-63.6
CT and MRCP	186.3	36.5	113.1-359.5
CT and HIDA	60.3	15.2	29.9-90.7
CT and US	58.4	10.6	37.0-79.7
US, CT and HIDA	53.5	21.3	10.9-96.0
Adjusted for demographics, co-morbidity, physical signs and admission service3				< 0.01
All studies done	94.7	36.4	21.8-167.5
US only	23.3	6.3	10.7-35.9
US and HIDA	33.9	13.7	6.4-61.4
CT only	42.3	10.6	21.0-63.7
CT and MRCP	195.4	35.1	125.1-256.8
CT and HIDA	55.5	14.64	26.2-84.9
CT and US	52.7	10.42	31.8-73.6
US, CT and HIDA	49.9	20.36	9.1-90.7

US: Ultrasound; HIDA: Nuclear Hepatobiliary Scan; MRCP: Magnetic resonance cholangiopancreatography.

¹Age and sex;

²Murphy's sign, leukocytosis, and fever;

³Surgical and medical services;

⁴Measure the differences in means (for more than two means, P < 0.05 indicates that at least one pair of means is statistically significantly different).