Christine P. McKenzie
Stanford University
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Featured researches published by Christine P. McKenzie.
International Journal of Obstetric Anesthesia | 2016
Christine P. McKenzie; B. Cobb; Edward T. Riley; Brendan Carvalho
INTRODUCTION The aim of this impact study was to compare the analgesic efficacy and side effect profile of programmed intermittent epidural boluses (PIEB)+patient-controlled epidural analgesia (PCEA) to continuous epidural infusion (CEI)+PCEA for maintenance labor analgesia after the introduction of PIEB at our institution. METHODS We conducted a retrospective analysis after replacing the background CEI with PIEB for our labor PCEA. Pre-change pump settings were CEI 12mL/h with PCEA (12mL bolus, lockout 15min); PIEB settings were a 9mL bolus every 45min with PCEA (10mL bolus, lockout 10min). We compared medical records of all women receiving epidural or combined spinal-epidural labor analgesia for vaginal delivery for two months before PIEB implementation to a two-month period of PIEB utilization following a five-month introductory familiarization period. The primary outcome was the proportion of women requiring rescue clinician boluses. RESULTS Fewer patients in the PIEB group required rescue clinician boluses compared to the CEI group (12% vs. 19%, P=0.012). Time to first rescue bolus request and total bolus dose were not different. Peak (median [IQR]) pain scores were 2[0-5] with CEI and 0[0-4] with PIEB. There was no difference in instrumental delivery rates. CONCLUSIONS Using PIEB compared to CEI as the background maintenance epidural analgesia method in conjunction with PCEA reduced the number of women requiring clinician rescue boluses while providing comparable labor analgesia. The findings of this clinical care impact study confirm the results of randomized controlled studies and suggest PIEB may be a preferable technique to CEI for the maintenance of labor analgesia.
Anesthesia & Analgesia | 2016
Brendan Carvalho; Ronald B. George; Benjamin Cobb; Christine P. McKenzie; Edward T. Riley
Programmed intermittent epidural bolus (PIEB) is an exciting new technology that has the potential to improve the maintenance of epidural labor analgesia. PIEB compared with a continuous epidural infusion (CEI) has the potential advantage of greater spread within the epidural space and therefore better sensory blockade. Studies have demonstrated a local anesthetic–sparing effect, fewer instrumental vaginal deliveries, less motor blockade, and improvements in maternal satisfaction with PIEB compared with CEI. However, the optimal PIEB regimen and pump settings remain unknown, and there are a number of logistical issues and practical considerations that should be considered when implementing PIEB. The PIEB bolus size and interval, PIEB start time delay period, and patient-controlled epidural analgesia bolus size and lockout time can influence the efficacy of PIEB used for epidural labor analgesia. Educating all members of the health care team is critical to the success of the technique. This review summarizes the role of PIEB for the maintenance of labor analgesia, outlines implementation strategies, suggests optimal settings, and presents potential limitations of the technique.
Regional Anesthesia and Pain Medicine | 2016
Christine P. McKenzie; Brendan Carvalho; Edward T. Riley
Abstract Intrathecal catheter devices using a catheter-over-needle design and softer flexible material have been introduced to clinical practice with the aim of reducing some of the complications such as postdural puncture headaches and paresthesias seen with previous versions of intrathecal catheters. We present a case series of 5 cesarean deliveries using the Wiley Spinal intrathecal system (Epimed, Johnstown, New York), which was recently approved by the US Food and Drug Administration. The intrathecal catheter system consists of a flexible 23-gauge intrathecal cannula over a 27-gauge pencil-point spinal needle. The placement of the intrathecal catheter was successful in all 5 cases; however, paresthesias in 3 cases and postdural puncture headaches in 2 cases complicated the placement and use of the device. Although the unique catheter-over-needle design facilitates the use of smaller-gauge spinal needles for dural puncture and larger-gauge catheters for medication administration, this case series using the Wiley Spinal suggests that paresthesias and postdural puncture headaches may still limit its widespread utilization. Future studies are needed to determine the true incidence of complications and to determine the role of continuous spinal anesthesia in the obstetric population.
Journal of Clinical Anesthesia | 2017
Christine P. McKenzie; Seden Akdagli; G. Abir; Brendan Carvalho
STUDY OBJECTIVE The primary aim was to evaluate institutional anesthetic techniques utilized for postpartum tubal ligation (PPTL). Secondarily, academic institutions were surveyed on their clinical practice for PPTL. DESIGN An institutional-specific retrospective review of patients with ICD-9 procedure codes for PPTL over a 2-year period was conducted. Obstetric anesthesia fellowship directors were surveyed on anesthetic management of PPTL. SETTING Labor and delivery unit. Internet survey. PATIENTS 202 PPTL procedures were reviewed. 47 institutions were surveyed; 26 responses were received. MEASUREMENTS Timing of PPTL, anesthetic management, postoperative pain and length of stay. MAIN RESULTS There was an epidural catheter reactivation failure rate of 26% (18/69 epidural catheter reactivation attempts). Time from epidural catheter insertion to PPTL was a significant factor associated with failure: median [IQR; range] time for successful versus failed epidural catheter reactivation was 17h [10-25; 3-55] and 28h [14-33; 5-42], respectively (P=0.028). Epidural catheter reactivation failure led to significantly longer times to provide surgical anesthesia than successful epidural catheter reactivation or primary spinal technique: median [IQR] 41min [33-54] versus 15min [12-21] and 19min [15-24], respectively (P<0.0001). Fifty-eight percent (15/26) of respondents routinely leave the labor epidural catheter in-situ if PPTL is planned. Sixty-five percent (17/26) and 7% (2/26) would not attempt to reactivate the epidural catheter for PPTL if >8h and >24h post-delivery, respectively. CONCLUSIONS Epidural catheter reactivation failure increases with longer intervals between catheter placement and PPTL. Failed epidural catheter reactivation increases anesthetic and operating room times. Our results and the significant variability in practice from our survey suggest recommendations on the timing and anesthetic management are needed to reduce unfulfilled PPTL procedures.
Obstetric Anesthesia Digest | 2017
Christine P. McKenzie; Benjamin Cobb; Edward T. Riley; Brendan Carvalho
Introduction: The aim of this impact study was to compare the analgesic efficacy and side effect profile of programmed intermittent epidural boluses (PIEB) + patient-controlled epidural analgesia (PCEA) to continuous epidural infusion (CEI) + PCEA for maintenance labor analgesia after the introduction of PIEB at our institution. Methods: We conducted a retrospective analysis after replacing the background CEI with PIEB for our labor PCEA. Pre-change pump settings were CEI 12 mL/h with PCEA (12 mL bolus, lockout 15 min); PIEB settings were a 9 mL bolus every 45 min with PCEA (10 mL bolus, lockout 10 min). We compared medical records of all women receiving epidural or combined spinal-epidural labor analgesia for vaginal delivery for two months before PIEB implementation to a two-month period of PIEB utilization following a five-month introductory familiarization period. The primary outcome was the proportion of women requiring rescue
Regional Anesthesia and Pain Medicine | 2016
Christine P. McKenzie; Brendan Carvalho; Edward T. Riley
with the results of our case series using the Wiley Spinal catheter-over-theneedle system. We are still strong advocates of intrathecal anesthesia and look forward to one day having a spinal catheter that is both efficacious and safe, with a low complication rate. Initially, we planned a multicenter trial with the Wiley spinal catheter and therefore began to use it for clinical care to gain experience prior to starting the study. However, after our experiencewith these 5 patients, we did not feel the product was ready for routine clinical care, and we cancelled our participation in the trial.
Anesthesia & Analgesia | 2017
Adrienne Duffield; Christine P. McKenzie; Brendan Carvalho; Victoria Yin; Yasser Y. El-Sayed; Edward T. Riley; Alexander J. Butwick
Obstetric Anesthesia Digest | 2017
A. Duffield; Christine P. McKenzie; Brendan Carvalho; V. Yin; Yasser Y. El-Sayed; Edward T. Riley; Alexander J. Butwick
Obstetric Anesthesia Digest | 2018
Christine P. McKenzie; Seden Akdagli; G. Abir; Brendan Carvalho
Obstetric Anesthesia Digest | 2017
Brendan Carvalho; Ronald B. George; Benjamin Cobb; Christine P. McKenzie; Edward T. Riley