AUTHORS: R. Prasad, M.D., F. Spielman, M.D., D. Mayer, M.D.
AFFILIATION: Department of Anesthesiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7010
Introduction. Epidural anesthesia is an excellent technique to control the pain of labor and delivery. Unfortunately, accidental dural puncture is a complication that can result in a severe, devastating headache. Traditional wisdom assumes that obese patients, inexperience or fatigue of the anesthesiologist contribute to this complication. Our study is the first to investigate which factor(s) are responsible for involuntary dural puncture.
Methods. After approval from the institutional committee on patient rights, we reviewed hospital and anesthetic records of all obstetric patients during the period October 1991 through September 1996 who had an accidental dural puncture while attempting to place an epidural catheter to provide analgesia for labor and delivery. We identified these patients employing our quality assurance records. The control group was established by matching each study patient with a randomly selected patient who successfully received epidural analgesia within six days of that study patient. The following data were recorded on all patients: age, height, weight, body surface area (BSA), the number of months of experience of the anesthesiology resident, degree of cervical dilation at the time of the epidural placement, interspace used, number of attempts with the epidural needle, position of the patient (lateral or sitting), and time of day. Statistical analysis was performed employing t-tests or Chi-square analysis as appropriate. A p-value of less than 0.05 was considered significant.
Results. 192 hospital records were reviewed (96 study, 96 control). No statistically significant difference between either group was found except for the number of attempts with the epidural needle. Success with the first attempt occurred in 71% of the control group, while it took three or more attempts to place the catheter in 53% of the study group (Table 1). The number of attempts could not be determined in 16 patients (13 study, 3 control).
| NO. ATTEMPTS | STUDY | CONTROL | TOTAL |
| 1 | 8 (10%) | 66 (71%) | 74 |
| 2 | 31 (37%) | 16 (17%) | 47 |
| 3 or more | 44 (53%) | 11 (12%) | 55 |
| Total | 83 (100%) | 93 (100%) |
Discussion. Our data suggest that fatigue, inexperience, and large
BSA do not contribute to accidental dural puncture. The only risk factor
that we have identified is multiple attempts to locate the epidural space.
For unknown reasons it appears that, for some parturients, identification
of the epidural space is difficult. We suggest that when unable to succeed
with the first attempt, subsequent passes of the epidural needle should
be made only after reassessing patient position, movement, and anatomy,
and with extreme diligence.