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Abstract
Please confirm that an ethics committee approval has been applied for or granted: Not relevant
Background and Aims Co-relation between USG measured epidural depth with actual depth together and BMI.
Methods 94 patients undergoing gynaecological procedures were recruited and study was done with supervision of professor from radiology.
Results Problem 1: Co-relation between measured depth (with the ultrasound) and the actual depth (with the needle) together with BMI- correlation can be identified by Scatter Matrix three variables (file attached as number 1) Correlations Needle depth USG BMI Needle depth 1 USG .668 1 BMI .643 .535 1 Also all the correlations are statistically significant at 95% level of confidence with reported p value <0.0001 Problem 2: Does BMI affect the needling A procedure of mediation analysis has been attempted which explains the casual relationship between two measuring methods that is being influenced by BMI. Underlying model ( image attached) Results: Direct and total effects Coeff s.e t Sig(two) c .6008 .0830 7.2395 .0000 a 3.2417 .4793 6.7634 .0000 b .0321 .0213 1.5085 .1363 c’ .4968 .1073 4.6309 .0000 Indirect effect (ab) and significance using normal distribution Value s.e LL95CI UL95CI Z Sig (two) Effect .1040 .0714 -.0359 .2439 1.4572 .1450 Bootstrap results for indirect effect (ab) Data Mean s.e LL95CI UL95CI Effect .1040 .1040 .0849 -.0557 .2967 Number of bootstrap re samples: 1000.
Number 1
Conclusions This is statistical significance (p value <0.001) of total effect with positive (0.6008). Though the effect size of BMI is of same direction (0.1040) it is not statistically significant as can be observed from the p-value >0.05 (0.1450).