The Influence of Body-mass Index on the Outcome of Spinal Anesthesia for Total Knee Replacement Arthroplasty

The Influence of Body-mass Index on the Outcome of Spinal Anesthesia for Total Knee Replacement Arthroplasty

In these prospective observational study, the investigators are trying to evaluate (1) the influence of body-mass index on spinal anesthetic outcome and (2) the determinants on spinal anesthetic outcome by logistic regression analysis.

Although the spread of spinal anesthetic drug is unpredictable, patients factors (age, gender, height,weight, body-mass index), spinal anatomy, anesthetic drug dose, and lumbosacral cerebrospinal fluid volume are known to be the determinants of sensory block level. Among these determinants, the influence of body-mass index (BMI) on spinal anesthesia is controversial, and there is no specific guideline showing the relative priority of these determinants.

Therefore, in these prospective observational study, the investigators are trying to evaluate (1) the influence of body-mass index on spinal anesthetic outcome and (2) the relative influence of these determinants on spinal anesthetic outcome by logistic regression analysis.

Inclusion Criteria:

• Patients who are undergoing spinal anesthesia in Samsung Medical Center during study period
• American Society of Anesthesiologist Physical Status classification I ~ III

Exclusion Criteria:

• Bupivacaine allergy
• medical history of spinal surgery
• Diabetic neuropathy
• active infection at the lumbosacral area
• other contraindication of spinal anesthesia