Gillian Hilton

Non-invasive haemoglobin measurement in patients undergoing elective Caesarean section

BACKGROUND The ability to measure haemoglobin (Hb) real-time and non-invasively offers important clinical value in the assessment of acute changes in maternal Hb during the peripartum period. This study evaluates the Masimo Rainbow SET(®) Radical-7 Pulse CO-Oximeter in a pregnant population undergoing Caesarean section (CS). METHODS Fifty patients undergoing elective CS were enrolled in this prospective, controlled study and followed for 48 h after surgery. Non-invasive Masimo Hb (SpHb) values were compared with laboratory Hb values from venous blood samples drawn at baseline, immediately post-CS, and 24 h post-CS using the Bland-Altman plots. Longitudinal analysis of SpHb changes over time was performed using mixed-effects regression modelling. RESULTS For the comparison between SpHb and laboratory Hb, SpHb displayed a significant positive bias at baseline {1.22 g dl(-1) [95% confidence interval (CI): 0.89-1.54]} and at 24 h post-CS [1.36 g dl(-1) (95% CI: 1.04-1.68)]. The bias immediately post-CS was 0.14 g dl(-1) (95% CI: -0.18 to 0.46). The limits of agreement at baseline, immediately post-CS, and at 24 h post-CS were: -0.9 and 3.33, -2.35 and 2.56, and -0.55 and 3.27 g dl(-1), respectively. The mean decrease in SpHb from baseline to 48 h post-CS was ∼1 g dl(-1). CONCLUSIONS The variability in bias and limits of agreements of the Rainbow SET(®) Radical-7 Pulse CO-Oximeter SpHb may limit its clinical utility for assessing Hb concentration in patients undergoing elective CS. Modifications are needed in the calibration of the device to improve accuracy and precision in an obstetric setting. The study was registered at clinicaltrials.gov (NCT01108471) before participant enrolment: URL=http://clinicaltrials.gov/ct2/show/NCT01108471?term=butwick&rank=1.

Active Warming Utilizing Combined IV Fluid and Forced-Air Warming Decreases Hypothermia and Improves Maternal Comfort During Cesarean Delivery: A Randomized Control Trial.

BACKGROUND:The aim of this study was to apply both IV fluid and forced-air warming to decrease perioperative hypothermia in women undergoing cesarean delivery with spinal anesthesia. The authors hypothesize that combined-modality active warming (AW) would increase maternal temperature on arrival at the postanesthesia care unit (PACU) and decrease the incidence of maternal perioperative hypothermia (<36°C) compared with no AW. METHODS:Forty-six healthy women (n = 23 per group) undergoing scheduled cesarean delivery with spinal anesthesia (10–12 mg bupivacaine + 10 &mgr;g fentanyl) were enrolled in this double-blinded, randomized controlled trial. Women were randomly assigned to receive either AW (warmed IV fluid and lower body forced-air warmer) or no warming (NW; blankets only). SpotOnTM Monitoring System was used to measure core temperature intraoperatively and for 1 hour postoperatively. The primary outcome measure was maternal temperature on arrival at the PACU. Secondary outcome measures included incidence of maternal perioperative hypothermia (<36°C), incidence of shivering, thermal comfort scores (0–100 scale), Apgar scores, and umbilical cord blood gas analysis. RESULTS:Demographic, obstetric, and surgical data were similar between study groups. The AW group (35.9°C ± 0.5°C) had a significantly higher temperature on arrival at the PACU compared with the NW group (35.5°C ± 0.5°C, P = 0.006; 95% confidence interval of mean difference, 0.1°C–0.7°C). Fourteen (64%) women in the AW group and 20 (91%) in the NW group were hypothermic during the study period (P = 0.031). Median (interquartile range) thermal comfort scores were 100 (95–100) in the AW group and 90 (70–100) in the NW group (P = 0.008). There were no significant differences in the incidence of intraoperative shivering (22% in the AW and 45% in the NW groups; P = 0.11), Apgar scores, or umbilical vein blood gas values between the study groups. CONCLUSIONS:Fluid combined with forced-air warming is effective in decreasing the incidence of perioperative hypothermia and improving maternal thermal comfort. However, despite multimodal AW, the majority of women became hypothermic, and shivering was not prevented. The findings suggest that combined AW for cesarean delivery with spinal anesthesia is difficult, and only modest benefit should be expected.

Non-invasive measurement of hemoglobin during cesarean hysterectomy: a case series

Obstetric patients diagnosed with abnormal placentation (placenta accreta, increta or percreta) are at increased risk of major postpartum hemorrhage and cesarean hysterectomy. Obstetric anesthesiologists are primarily involved in intraoperative transfusion management in these cases. Hemoglobin assessment is invaluable for assisting transfusion decision-making during the acute period of obstetric hemorrhage. However, laboratory and point-of-care tests of hemoglobin concentration are time-dependent and intermittent, and do not provide a real-time assessment of change during the acute phase of blood loss. A new non-invasive hemoglobin monitor has been introduced recently, which provides real-time measurement of hemoglobin values (SpHb) using multi-wavelength pulse co-oximetry. We present a review of five patients with suspected abnormal placentation who received SpHb monitoring during cesarean hysterectomy at our institution. We discuss the potential clinical utility of non-invasive hemoglobin monitoring for pregnant patients at high risk of obstetric hemorrhage, and the potential role of SpHb in guiding transfusion therapy.

Checklists and multidisciplinary team performance during simulated obstetric hemorrhage

BACKGROUND Checklists can optimize team performance during medical crises. However, there has been limited examination of checklist use during obstetric crises. In this simulation study we exposed multidisciplinary teams to checklist training to evaluate checklist use and team performance during a severe postpartum hemorrhage. METHODS Fourteen multidisciplinary teams participated in a postpartum hemorrhage simulation occurring after vaginal delivery. Before participating, each team received checklist training. The primary study outcome was whether each team used the checklist during the simulation. Secondary outcomes were the times taken to activate our institution-specific massive transfusion protocol and commence red blood cell transfusion, and whether a designated checklist reader was used. RESULTS The majority of teams (12/14 (86%)) used the checklist. Red blood cell transfusion was administered by all teams. The median [IQR] times taken to activate the massive transfusion protocol and transfuse red blood cells were 5min 14s [3:23-6:43] and 14min 40s [12:56-17:28], respectively. A designated checklist reader was used by 7/12 (58%) teams that used the checklist. Among teams that used a checklist with versus without a designated reader, we observed no differences in the times to activate the massive transfusion protocol or to commence red blood cell transfusion (P>0.05). CONCLUSIONS Although checklist training was effective in promoting checklist use, multidisciplinary teams varied in their scope of checklist use during a postpartum hemorrhage simulation. Future studies are required to determine whether structured checklist training can result in more standardized checklist use during a postpartum hemorrhage.

Prospective longitudinal cohort questionnaire assessment of labouring women's preference both pre- and post-delivery for either reduced pain intensity for a longer duration or greater pain intensity for a shorter duration

BACKGROUND Assessments of labour pain focus on pain intensity, not on duration. We aimed to assess the importance labouring women apply to pain intensity and duration before labour and post-delivery. METHODS Forty healthy women scheduled for labour induction were enrolled in this institutional review board-approved, prospective cohort study. Participants completed a pain preference questionnaire before active labour and within 24-h of delivery. The questionnaire consisted of seven stem questions that evaluated preference for pain intensity or duration. The pain preference ratio was determined by dividing the percentage of women who preferred reduced pain intensity for longer duration by that of those who preferred greater pain intensity for shorter duration (estimate of the odds). The overall hypothetical pain burden was determined by multiplying intensity by time. All questions presented the same overall hypothetical pain burden. RESULTS Pain preference questionnaire scores demonstrated preference for low intensity pain for a longer duration rather than higher intensity for a shorter duration, both pre-labour (P<0.001) and post-delivery (P<0.001): the null median imputed as 3 of 6 (i.e. no preference for pain intensity over pain duration). This preference for pain duration over intensity was greater post-delivery compared with before labour (P=0.03). There was a significant correlation (r=0.83; P=0.04) between the pain preference ratio vs overall hypothetical pain burden before labour but not after delivery (r=0.28; P=0.59). CONCLUSIONS In this preliminary labour assessment, women preferred lower pain intensity at the cost of longer pain duration. This suggests that pain intensity is the primary driver of hypothetical pain burden-a preference reinforced post-delivery.

The impact of breastfeeding on postpartum pain after vaginal and cesarean delivery

STUDY OBJECTIVE Oxytocin may play a role in pain modulation. The analgesic effects of breastfeeding with its associated endogenous oxytocin release have not been well investigated. To determine the impact of breastfeeding on incisional, perineal, and cramping pain after cesarean and vaginal delivery. DESIGN Institutional review board-approved prospective observational study. SETTING Labor and delivery and maternity wards. PATIENTS Healthy (American Society of Anesthesiology physical statuses 1 and 2) multiparous women who had cesarean (n = 40) and vaginal (n = 43) deliveries of singleton term infants and who were breastfeeding were enrolled. INTERVENTIONS Women completed diaries to record incisional, perineal, or cramping pain scores 5 minutes before, during, and 5 minutes after breastfeeding. MEASUREMENTS Demographic, obstetric, and neonatal variables, as well as analgesic use, were recorded. MAIN RESULTS There was no difference in incisional pain before, during, and after breastfeeding in women post-cesarean delivery. Cramping pain was significantly increased during, as compared with before or after breastfeeding in both the vaginal (P < .001) and cesarean (P < .001) delivery cohorts. CONCLUSIONS There was no analgesic effect on incisional pain during breastfeeding, indicating that endogenous oxytocin associated with breastfeeding may not play a significant role in postpartum cesarean wound pain modulation. Breastfeeding increased cramping pain after vaginal and cesarean delivery. The increase in cramping pain is most likely due to the breastfeeding-associated oxytocin surge increasing uterine tone.

Simulation Study Assessing Healthcare Provider's Knowledge of Pre-Eclampsia and Eclampsia in a Tertiary Referral Center.

Introduction The aim of the study was to assess knowledge of labor and delivery healthcare providers at a tertiary referral center in the management of pre-eclampsia and eclampsia. Methods Thirteen multidisciplinary teams participated in this institutional review board–exempt study. Each group encountered the same scenario that involved a pre-eclamptic parturient who progressed to eclampsia. The participants were unaware of the scenario topic before the drill and that key interventions would be recorded and timed. Seven of 13 groups were randomized to have a cognitive aid available. Results Twelve of 13 groups attempted to lower the blood pressure; however, only 7 of 12 groups used the correct first-line antihypertensive medication as per the American College of Obstetricians and Gynecologists’ guidelines. All groups requested and administered the correct bolus dose of magnesium (4–6 g intravenously). Only 2 of 13 groups took appropriate action to lower the blood pressure to a “safe range” before induction of general anesthesia, and 4 of the 13 anesthesiologists made drug modifications for induction of anesthesia. None of the 7 groups randomized to have a cognitive aid used it. Conclusions Our results show widespread magnesium sulfate utilization; however, the use of antihypertensive medication is not universally administered in compliance with current guidelines. The importance of blood pressure management to reduce maternal morbidity and mortality in the setting of pre-eclampsia needs to be emphasized. Interestingly, availability of a cognitive aid did not ensure its utilization in this scenario. Findings suggest that for cognitive aids to be effectively used, it is essential that staff has been trained and become familiar with them before an emergent event.

Kinked Perifix FX Springwound epidural catheters

To the Editor, We recently experienced problems with post-insertion kinking of a newer epidural catheter, Perifix FX Springwound (B. Braun Medical Inc., Bethlehem, PA, USA), in three labouring parturients. The open-tip uniport version of the 19-G Perifix FX Springwound catheter is the standard epidural catheter used in labour and delivery at our institution. A labour epidural was placed without difficulty in two non-obese parturients in the sitting position. In both cases, the epidural space was identified using a saline loss of resistance technique on a single pass. The catheter threaded easily and was withdrawn to the appropriate skin depth to leave 5 cm of catheter within the epidural space. The catheter was taped to the patients’ backs, and following negative aspiration, attempts were made to administer an initial dose of 0.125% bupivacaine 5 mL. There was immediate resistance in both instances. The visible parts of the catheters were examined for kinks but none were found. The catheter connectors were changed, but there was still resistance to injection despite using several syringes of differing sizes. Since no reversible cause was found, the catheters were withdrawn. On inspection, a kink was identified close to the distal end of each catheter. New catheters of the same type were placed successfully in both patients. In a third incident, it was not possible to inject local anesthetic with a 20 mL syringe following uncomplicated catheter placement; however, administration of the dose was possible with a 5 mL syringe. Due to remaining high resistance, the epidural infusion pump would not deliver correctly and it alarmed continuously. Since the patient was not keen to have the epidural replaced, she received intermittent local anesthetic boluses to maintain analgesia during her labour and delivery. She had an effective block from the epidural catheter placement, confirming that the distal end was in the epidural space. As in the other two cases documented above, upon removal of the catheter, a kinked segment could be identified close to the distal end. Upon visible inspection of two of the catheters, kinks were visible at 32 mm and 35 mm from the distal end. Microscopic examination of these two catheters revealed that the metal supporting coil had been bent irreversibly (Figure). With the catheters in the unkinked position, it was possible to flush them easily without resistance, thus patency was not an issue. The angle of approach during each catheter placement was approximately perpendicular to the skin; therefore, there is no reason to presume that the catheters were forced into a sharply angled upward direction that caused them to kink. Previously, we have used the closed-tip multiport version of the Perifix FX Springwound catheters, which were also prone to kinking on occasion. We had assumed they were prone to kinking at one of the catheter ports; however, after withdrawing the catheters and their distal ends, they were observed to kink at the portal sites of structural weakness. In response, we switched to use of the open-tip version to avoid catheter kinking. With the softer wire-reinforced tubing, it has been shown that open-tip and multiport catheters functioned equally well. Eckmann analyzed bending stiffness of six epidural catheters and determined that the bending stiffness of the coil-reinforced catheter group was significantly less than that of the styletted, clear nylon, radiopaque nylon, and polyurethane catheters. The superior bending flexibility of the wire-reinforced catheters G. Hilton, MBChB (&) C. G. Jette, MD Y.-B. Ouyang, PhD E. T. Riley, MD Stanford University School of Medicine, Stanford, CA, USA e-mail: ghilton@stanford.edu

On-Time Scheduled Cesarean Delivery Start Time Process-Improvement Initiative

INTRODUCTION: Cesarean deliveries comprise approximately 30% of all births, many of which are scheduled. Given the labile nature of labor and delivery units, scheduled cesarean deliveries are often delayed. Our aim was to improve on-time scheduled cesarean delivery start times. METHODS: A multidisciplinary team (obstetrician–gynecologist, nursing, anesthesia, and hospital administration) met to review scheduled cesarean delivery data, identify logistic barriers to on-time starts, and develop a plan to improve cesarean delivery start times. After identifying possible barriers to on-time starts, the following process was instituted: planned preoperative visit 1–2 days before scheduled cesarean delivery, mandatory submission of History & Physical and consent forms by the time of the preoperative visit, and initial preparation of the first scheduled patient for cesaren delivery by nighttime nursing before morning change of shift. The process launched on March 1, 2013. Data from scheduled cesarean deliveries 6 months before and 3 months after the initiative were reviewed and analyzed. RESULTS: Of 1,298 total cesarean deliveries, 423 were scheduled, defined as cesarean delivery scheduled at least 24 hours in advance (300 before and 123 after the initiative). Sixty-four of 300 scheduled cesarean deliveries (21.3%) were on time before compared with 67 of 123 (54.5%) after the initiative began (P<.001). Among delayed cases, there was no difference in the average delay time between those before and after the initiative (55.7 compared with 54.4 minutes P=.93); however, 50.7% of cases were either on time or delayed by 15 minutes or less before the initiative compared with 69.9% of cases after (P<.001). CONCLUSIONS: A multidisciplinary initiative significantly increased scheduled cesarean delivery on-time start times.

Noninvasive Measurement of Hemoglobin During Cesarean Hysterectomy: A Case Series

Obstetric patients with abnormal placentation are at increased risk for major postpartum hemorrhage and cesarean hysterectomy. Transfusion therapy is often part of the management for these patients. The use of real-time noninvasive hemoglobin (Hgb) measurement may be beneficial because laboratory and point-of-care tests of Hgb concentration are time-dependent and intermittent and do not provide a real-time assessment of changes during the acute phase of bleeding. A new noninvasive Hgb monitor provides real-time measurement of hemoglobin values (SpHb) using multiwavelength pulse cooximetry. This case series presents 5 patients with suspected abnormal placentation who had SpHb monitoring during cesarean hysterectomy. The 5 patients had preoperative diagnoses of placenta accreta and underwent cesarean hysterectomy. SpHb was continuously monitored and data were downloaded from the cooximeter. All patients had a radial arterial line and wide-bore intravenous cannulas placed before surgery. All relevant anesthetic and surgical data and SpHb and laboratory values for venous and arterial Hgb were collected and reviewed. Patient 1 was a 36-year-old patient who received combined spinal-epidural (CSE) anesthesia with hyperbaric bupivacaine, fentanyl, and morphine. Massive hemorrhage occurred at the site of placental adherence, and a hysterectomy was performed. Intraoperatively the patient developed respiratory distress from pulmonary edema requiring rapid-sequence induction of general anesthesia. After intubation, she was treated with furosemide. On postoperative day 1, she was successfully extubated and transferred to the postpartum unit with no postoperative complications. Patient 2 had a complete placenta previa and underwent emergency cesarean section after presenting with vaginal bleeding at 32 weeks gestation. Manual removal of the placenta was not attempted after delivery of the infant because of presumed placenta percreta. A hysterectomy was performed, and she had no postoperative complications. Patient 3 had CSE anesthesia and after hysterotomy and delivery, she underwent hysterectomy for presumed placenta accreta. She was hemodynamically stable during surgery and did not require conversion to general anesthesia. Patient 4 had an urgent cesarean delivery at 31 weeks gestation because of premature rupture of membranes. She received CSE anesthesia. An attempt to deliver the placenta indicated there was no clear plane between the placenta and uterus. Because of uncontrolled bleeding, hysterectomy was performed. She was hemodynamically stable during the perioperative period and had no postoperative complications. The fifth patient had CSE anesthesia. After hysterotomy and delivery of the infant, the presence of placenta percreta was confirmed and the obstetrician performed a hysterectomy. She was hemodynamically stable throughout the perioperative period and had no postoperative complications. All patients had at least 2L of total estimated blood loss and 4 patients received red blood cell transfusions; they also required freshfrozen plasma and platelet transfusions. A total of 17 arterial blood samples were obtained from the 5 patients for laboratory Hgb determinations. The SpHb value at the approximated time of blood sampling was also determined and compared with the laboratory Hgb values. The SpHb values were higher than laboratory Hgb values in 16 of 17 samples. The median difference between SpHb and laboratory Hgb values was 2 g/dL. The median SpHb at 10.4 g/dL was significantly higher than the median laboratory Hgb value of 8.7 g/dL. The correlation between SpHb and laboratory Hgb values was R=0.90 (P<0.001). Although the correlation between the laboratory and cooximeter values was significant, the device overestimated SpHb values. A formal prospective study assessing SpHb changes in patients undergoing elective cesarean delivery is underway currently to assess device accuracy and precision. The differences in the SpHb and laboratory Hgb values could be attributed to the retrospective collection of data, which did not provide the exact timing of laboratory blood sampling. Rapid fluid shifts and acute blood loss could have affected the pulsatile index, which impacts the accuracy of SpHb values. However, for all but one sample the index was >0.75, indicating a reliable signal. More scientific testing of this device is necessary to assess SpHb changes during the peripartum and postpartum periods and to determine its reliability in measuring Hgb, especially during periods of severe blood loss.