The relationship between body mass index (BMI) with the distance of the skin-epidural space in 3rd and 4th lumbar epidural anesthesia in nonobstetric surgery of Indonesian patients

Abstract

Skin to epidural space distance varies in an insertion of epidural needle which can greatly affect
the identification of the epidural space and epidural anesthesia complications. Therefore, a
careful prediction of skin to epidural space distance is needed in doing insertions. The purpose
of this study was to evaluate the relationship between body mass index (BMI) and the distance
of skin to the epidural space in the 3rd – 4th lumbar epidural anesthesia in nonobstetric surgery of
Indonesian patients. This was a prospective observational study with cross sectional design
involving patients of both sexes between the age 18-65 years with ASA physical status I-II who
underwent non obstetric surgery with 3rd-4th lumbar epidural anesthesia in Dr. Sardjito General
Hospital, Yogyakarta and in Satellite Hospital. Weight, height and BMI were considered as the
independent variables, whereas skin to epidural space distance was considered as dependent
variable. Data were collected and analyzed using multiple regression analysis continued using
Pearson’s correlation test to evaluate the relationship between BMI and skin to epidural space
distance. One hundred patients selected from October to December 2011 were evaluated in this
study. The mean of weight, height and BMI were 57.35±11.59 kg, 155.98±5.88 cm and
23.52±4.26 kg/m2, respectively. The mean of skin to epidural space distance of non obstetric
surgery of Indonesian patients was 40.89±9.95 mm. Multiple regression analysis showed that
BMI had a strongest relationship (r= 0.81; p<0.03) with skin to epidural space distance compared
to weight (r= 0.11; p=0.78) and height (r= 0.04; p<0.83). Further analysis using Pearson
correlation test showed that a significantly good correlation of BMI (r=0.92; p=0.001) and
body weight (r=0.87; p=0.001) with the skin to epidural space distance were observed. In
conclusion, BMI and body weight have a significant correlation with the skin to epidural space
distance in non obstetric surgery patient.