Comparison of 'whoosh' and modified 'swoosh' test for identification of the caudal epidural space in children.
BACKGROUND
Caudal analgesia is widely used in pediatric anesthesia practice. The 'whoosh' test which uses air to identify the epidural space, has been recommended as a guide for successful needle placement. However, the use of air may be associated with an incidence of neurological complications. The 'swoosh' test avoids the injection of air and was originally performed using injection of a local anesthetic solution. A comparison was made between the 'whoosh' test and a modified 'swoosh' test using saline to identify the caudal epidural space in children.


METHODS
We studied 60 children of either sex in the age group of 2-8 years undergoing inguinal herniotomy. During insertion of the caudal block, a stethoscope was placed over the lower lumbar spine to note the presence or absence of 'whoosh' or 'swoosh', by an independent observer who was blinded to the injection of 1 ml of air or saline which was given simultaneously by the operator into the caudal space. The operator's clinical impression of successful insertion of the needle was also recorded and correlated with the presence or absence of 'whoosh' or 'swoosh'. In addition, the need for supplemental intraoperative analgesia was noted.


RESULTS
Overall success rate of caudal block using the 'whoosh' and modified 'swoosh' tests was found to be 96.6% and 93.3%, respectively as judged by the lack of supplementary perioperative analgesia. The sensitivity, specificity and positive predictive value of the 'whoosh' test and clinical predictors of caudal placement was found to be 100% whereas the modified 'swoosh' test had a sensitivity of 93%, specificity of 50% and a positive predictive value of 96%. However, statistically there was no significant difference between the clinical predictors, 'whoosh' and the modified 'swoosh' test for identification of the caudal epidural space.


CONCLUSIONS
The modified 'swoosh' test is as reliable as the 'whoosh' test and we recommend it for identification of the caudal epidural space in children as it avoids injection of air into the caudal space.
Talwar
Vandana
V
Department of Anaesthesia and Intensive Care, VMMC and Safdarjang Hospital, New Delhi, India. vandtal@yahoo.com
Tyagi
Rohit
R
Mullick
Parul
P
Gogia
Anoop Raj
AR
D000388:Air; D000763:Anesthesia, Caudal / Q000379:methods*; D001314:Auscultation / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D004824:Epidural Space; D005260:Female; D006552:Hernia, Inguinal / Q000601:surgery; D006801:Humans; D008297:Male; D009339:Needles; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000008:administration & dosage
D012965:Sodium Chloride