Association of pain catastrophizing with labor pain and analgesia consumption in obstetrical patients.

INTRODUCTION: Pain catastrophizing is an exaggerated negative orientation to painful stimuli which in obstetric patients is associated with fear of overwhelming labor pain and negative pain-related outcomes. This study aimed to quantitatively examine the association of pain catastrophizing with maternal labor pain outcomes. METHODS: We conducted a prospective observational study of women admitted for a vaginal trial of labor. Subjects completed the 13-item Pain Catastrophizing scale (PCS) questionnaire (scored 0 to 52, higher scores representing greater catastrophizing). Pain was assessed at baseline and at request for neuraxial labor analgesia. Labor and postpartum pain intensity was assessed as the average area under the pain intensity by time curve. Pain at request for analgesia, labor pain, postpartum pain, analgesic consumption, and quality of recovery was compared between high (PCS ≥ 17) and low catastrophizing groups. RESULTS: Data from 138/157 (88%) subjects were included in the analysis. Median (IQR) pain scores at request for analgesia were 9 (8,10) and 8 (6,9), a difference of 1 (95% CI 0 to 2.5, P = 0.008) in high-catastrophizing and in low-catastrophizing groups, respectively. Adjusted pain during labor, postpartum pain and opioid analgesic use were not significantly different. High-catastrophizers reported less comfort, ability to mobilize and less control during hospitalization. Post-discharge there were no differences in pain or analgesic use. CONCLUSION: We did not observe greater labor or post-delivery pain or increased analgesic use in high-catastrophizing parturients. High catastrophizers reported greater pain when requesting analgesia, which is consistent with the role of catastrophizing in intensifying the experience of pain.

A survey of United States obstetric anesthesiologists' perceived value of obstetric anesthesiology fellowship.

INTRODUCTION: Subspecialty training in obstetric anesthesiology is associated with improved patient outcomes and reduced anesthesia-related morbidity and mortality. Despite this, the demand for fellowship-trained obstetric anesthesiologists far exceeds the supply. This survey study aimed to evaluate the perceived value of obstetric anesthesiology subspecialty training on career trajectory, job satisfaction, quality of life, and job autonomy. METHODS: After Institutional Review Board approval, we conducted a cross-sectional study of fellowship-trained obstetric anesthesiologists in the United States of America. In March and April 2022, program directors of obstetric anesthesiology fellowships distributed an electronic survey link containing 29 multiple-choice questions to their program alumni. Survey content included respondent demographic characteristics, practice models, career information, and perceived value of an obstetric anesthesiology fellowship. RESULTS: We surveyed 217/502 (43%) fellowship-trained obstetric anesthesiologists with a response rate of 158/217 (73%). Most worked in urban, academic, and level IV perinatal health centers. The majority believed an obstetric anesthesiology fellowship was "extremely beneficial" (77%), enhanced quality of life (84%), improved the quality of patient care (99%), and was influential in helping obtain their first post-training job (86%). The perceived value of the fellowship included an enhanced career trajectory, a sense of purpose, improved job satisfaction, a sense of work community, lower burnout, involvement in maternal health initiatives, increased mentorship, and departmental leadership. CONCLUSION: In this survey study, fellowship-trained obstetric anesthesiologists perceived a positive impact of fellowship training on career trajectory, job protection and autonomy, quality of life, and job satisfaction. This information may be meaningful to trainees considering pursuing a fellowship and a career in obstetric anesthesiology.

Effect of companion presence on maternal satisfaction during neuraxial catheter placement for labor analgesia: a randomized clinical trial.

BACKGROUND: Neuraxial labor analgesia is frequently achieved after placing an epidural catheter under sterile conditions. There is no consensus on the risk versus benefit of allowing a parturient's companion to remain during the procedure. We sought to assess the effect of the presence of a companion on maternal satisfaction and anxiety during neuraxial catheter placement for labor analgesia. METHODS: Healthy nulliparous parturients planning to receive neuraxial labor analgesia after admission to labor, and who had a companion with them at the time of interview, were randomized to having a companion present or not present in the labor and delivery room during neuraxial catheter placement. Participants completed questionnaires to assess maternal anxiety, pain catastrophizing and health literacy. Satisfaction was scored on 5-point Likert scale (1- highly dissatisfied, 2- dissatisfied, 3- neutral, 4- satisfied, 5- highly satisfied). RESULTS: A total of 143 participants completed the study. The Wilcoxon-Mann-Whitney odds ratio for a random pair of satisfaction scores for a woman with her companion present compared with companion not present was 1.93 (95% CI 1.30 to 2.81, P=0.001). Anxiety scores were decreased following the procedure (P=0.39) in both groups. Eighty-nine percent of women randomized to companion not present would have preferred to have a companion present (P <0.001) compared with only one with their companion present who would have preferred her companion to be not present (P=0.99). CONCLUSION: Maternal satisfaction can be improved with the presence of a companion in the labor and delivery room at the time of neuraxial catheter placement for labor analgesia.

Anesthetic management of parturients with Arnold Chiari malformation-I: a multicenter retrospective study.

BACKGROUND: Consensus regarding the safest mode of delivery and anesthetic management for parturients with Arnold Chiari malformation-I (ACM-I) remains controversial. This study assessed their anesthetic management and reported anesthetic complications during hospitalization for delivery. METHODS: This was a multicenter, retrospective, cohort study of patients with ACM-I undergoing vaginal or cesarean delivery. Data were obtained from the electronic databases of four United States academic institutions using International Classification of Diseases (ICD) codes from 2007-2017 at three sites and 2004-2017 at one site. The primary outcome was anesthetic complications. RESULTS: Data were analyzed for 185 deliveries in 148 patients. Diagnosis of ACM-I was made prior to delivery in 147 (80%) cases. Pre-delivery neurosurgical consultation for management of ACM-I was performed in 53 (36%) patients. Pre-existing symptoms were recorded for 89 (48%) of the deliveries. Vaginal deliveries occurred in 80 (43%) cases, and 62 women (78%) received neuraxial labor analgesia. Cesarean delivery was performed in 105 (57%) cases, of which 70 women (67%) had neuraxial anesthesia and 34 (32%) received general anesthesia. Post-dural puncture headache was reported in three (2%) patients who had neuraxial anesthesia, and in two (12%) patients with syringomyelia. There was one (3%) reported case of aspiration pneumonia with general anesthesia. CONCLUSIONS: The findings suggest that anesthetic complications occur infrequently in patients with ACM-I regardless of the anesthetic management. Although institutional preference in anesthetic and obstetric care appears to drive patient management, the findings suggest that an individualized approach has favorable outcomes in this population.

Neuraxial labor analgesia is not an independent predictor of perineal lacerations after vaginal delivery of patients with intrauterine fetal demise.

INTRODUCTION: The role of neuraxial labor analgesia in perineal trauma following live births is controversial, and no studies have assessed the association in women delivering an intrauterine fetal demise. We evaluated the relationship between neuraxial labor analgesia and perineal laceration in these patients. METHODS: This was a retrospective case-control study of women with a diagnosis of fetal death after 20weeks of gestation, a vaginal delivery, and an Apgar score of 0 at delivery, during the period from January 2007 through December 2015. The presence of a perineal laceration and its severity, graded from grade I to IV based on the 2014 American College of Obstetricians and Gynecologists guidelines, was recorded. RESULTS: A total of 329/422 (78%) patients received neuraxial, and 93/422 (22%) non-neuraxial, labor analgesia. A perineal laceration occurred in 23% in the neuraxial versus 10% in the non-neuraxial analgesia group, a difference of 13% (95% CI of difference 4% to 20%, P=0.005). After adjusting for confounder bias, greater birthweight (OR 4.22, 95% CI 3.00 to 5.92, P<0.001) and lower parity (OR 0.44, 95% CI 0.24 to 0.82, P=0.009), but not neuraxial analgesia (OR 1.29, 95% CI 0.47 to 3.57, P=0.61) were independent predictors of perineal laceration. The maintenance concentration of bupivacaine did not affect the rate of perineal injury. CONCLUSIONS: Neuraxial labor analgesia does not appear to be an independent risk for a perineal laceration in patients with intrauterine fetal demise. Our data suggests that the use of neuraxial analgesia should not raise concern about increased rates of perineal injury.

Maternal sedation during scheduled versus unscheduled cesarean delivery: implications for skin-to-skin contact.

BACKGROUND: Early maternal skin-to-skin contact confers numerous benefits to the newborn, but maternal sedation during cesarean delivery could have safety implications for early skin-to-skin contact in the operating room. We compared patient-reported and observer-assessed levels of sedation during unscheduled and scheduled cesarean deliveries. METHODS: Laboring women undergoing unscheduled cesarean delivery with epidural anesthesia, and scheduled cesarean delivery with spinal anesthesia were enrolled. Sedation levels, measured using patient-reported (1=least sedated to 10=most sedated) and observer-assessed (0=most sedated to 5=least sedated) scales, were evaluated at baseline and 15, 30, 45, and 60min following a T4 sensory level. The primary outcomes were patient-reported sedation at 45min and the areas under the sedation curves. RESULTS: Patient-reported levels of sedation were greater at 45min in laboring women undergoing unscheduled (median 7.5, IQR 5-9) versus scheduled cesarean delivery (median 4, IQR 3-6) (difference in medians 3.5, 99% CI 0 to 5). Observer-assessed sedation was not different between groups. The area under the time curve for patient-reported sedation was greater in the unscheduled group, median difference 162 score min (95% CI 52 to 255). The area under the time curve for observer-assessed sedation was greater in the unscheduled group, median difference 26 score min (99% CI 0 to 41). Times to skin-to-skin contact and breastfeeding were not different. CONCLUSIONS: Women undergoing unscheduled cesarean deliveries are more sedated than women undergoing scheduled cesarean deliveries. Skin-to-skin protocols for cesarean deliveries must consider maternal sedation and anesthesiologists should use sedating medications judiciously.

Virtual airway simulation to improve dexterity among novices performing fibreoptic intubation.

We developed a virtual reality software application (iLarynx) using built-in accelerometer properties of the iPhone(®) or iPad(®) (Apple Inc., Cupertino, CA, USA) that mimics hand movements for the performance of fibreoptic skills. Twenty novice medical students were randomly assigned to virtual airway training with the iLarynx software or no additional training. Eight out of the 10 subjects in the standard training group had at least one failed (> 120 s) attempt compared with two out of the 10 participants in the iLarynx group (p = 0.01). There were a total of 24 failed attempts in the standard training group and four in the iLarynx group (p < 0.005). Cusum analysis demonstrated continued group improvement in the iLarynx, but not in the standard training group. Virtual airway simulation using freely available software on a smartphone/tablet device improves dexterity among novices performing upper airway endoscopy.

Palliation of abdominal aortic aneurysms in the endovascular era.

OBJECTIVES: To establish outcome of patients with abdominal aortic aneurysm (AAA) deemed unfit for repair. DESIGN: Retrospective non-randomised study. MATERIALS AND METHODS: Identification of males with >5.5 cm or females with >5.0 cm AAA turned down for elective repair between 01/01/2006-24/07/2009 from a prospective database. Comorbidities, reasons for non-intervention, aneurysm size, survival, use of CPEX (cardio-pulmonary exercise) testing and cause of death were analysed. Although well-established at the time, patients unfit for open operation were not considered for endovascular repair. RESULTS: Seventy two patients were unsuitable for AAA repair. Aneurysm size ranged from 5.3 cm to 12 cm. Functional status, comorbidity and patient preference determined decision to palliate. Sixty percent of patients were alive at study close. Aneurysm rupture was cause of death in 46%. CPEX testing was performed in 54%, whose mortality was 28%, vs. 54% in the non-CPEX group (P < 0.05). Median survival of patients with 5.1-6.0 cm AAA was 44 months and 11% died of rupture. Between 6.1 and 7.0 cm median survival was 26 months and 20% died of rupture. However, with >7 cm aneurysms, survival was 6 months and 43% ruptured. CONCLUSION: Under half the deaths in our comorbid cohort were due to rupture. However, decision to palliate may be revisited as risk-benefit ratio changes with aneurysm expansion.

Systemic metoclopramide to prevent postoperative nausea and vomiting: a meta-analysis without Fujii's studies.

Previous evidence suggested that 10 mg systemic metoclopramide is not effective to prevent postoperative nausea and/or vomiting (PONV) in patients receiving general anaesthesia. However, the evidence included data with questioned validity by the author Yoshitaka Fujii. The objective of the current study was to examine the effect of a systemic dose of 10 mg metoclopramide to prevent PONV. This quantitative systematic review was performed according to the PRISMA guidelines. A wide search was performed to identify randomized clinical trials that evaluated systemic 10 mg metoclopramide as a prophylactic agent to reduce PONV. Meta-analysis was performed using a random-effect model. Thirty trials evaluating the effect of 10 mg systemic metoclopramide in 3328 subjects on PONV outcomes were included. Metoclopramide reduced the incidence of 24 h PONV compared with control, odds ratio (OR) [95% confidence interval (CI)] of 0.58 (0.43-0.78), number needed to treat (NNT)=7.8. When evaluated as separate outcomes, metoclopramide also decreased the incidence of nausea over 24 h, OR (95% CI) of 0.51 (0.38-0.68), NNT=7.1, and vomiting over 24 h, OR (95% CI) of 0.51 (0.40-0.66), NNT=8.3. A post hoc analysis examining three studies with questioned validity performed by the author Yoshitaka Fujii that would meet criteria for inclusion in the current study did not demonstrate a significant benefit of metoclopramide compared with control on the incidence of 24 h PONV. Our findings suggest that metoclopramide 10 mg i.v. is effective to prevent PONV in patients having surgical procedures under general anaesthesia. Metoclopramide seems to be a reasonable agent to prevent PONV.

The effect of intravenous magnesium therapy on the duration of intrathecal fentanyl labor analgesia.

BACKGROUND: Magnesium has been reported to augment the analgesic effects of opioids when co-administered into the cerebrospinal fluid. The purpose of this study was to determine the influence of intravenous magnesium therapy administered for preeclampsia on the duration of intrathecal fentanyl analgesia for labor. METHODS: Thirty-four nulliparous parturients having labor induced for preeclampsia and receiving intravenous magnesium therapy were recruited. Thirty-four nulliparous patients having labor induced for elective or medical reasons were recruited as controls. At request for analgesia, baseline serum magnesium levels were obtained and combined spinal-epidural analgesia was initiated with intrathecal fentanyl 25µg. Before injection of fentanyl, a sample of cerebrospinal fluid was obtained for magnesium assay. An epidural catheter was sited but no additional medications were administered until the second request for analgesia. The primary outcome was duration of intrathecal fentanyl analgesia. RESULTS: There was no difference in the median duration of analgesia between the magnesium [79min (95% CI 76 to 82)] and control groups [69min (95% CI 56 to 82)] (difference between medians: 10min (95% CI -4 to 21min; P=0.16). There was neither a relationship between the serum and cerebrospinal fluid magnesium concentrations nor the cerebrospinal magnesium concentration and duration of intrathecal fentanyl analgesia. CONCLUSIONS: Intravenous magnesium therapy at doses typically used for seizure prophylaxis in preeclampsia did not influence the duration of intrathecal fentanyl labor analgesia. However, this study may have been underpowered to detect a difference and future study is warranted.

The association between allogeneic perioperative blood transfusion on tumour recurrence and survival in patients with advanced ovarian cancer.

OBJECTIVE: To evaluate the association between perioperative blood transfusion on the recurrence and survival of patient with advanced ovarian cancer. BACKGROUND: Cytoreductive surgery for ovarian cancer can be an extensive procedure often requiring allogeneic blood transfusions. Blood transfusions can have detrimental effects on immune function which can lead to a decrease in the organism ability to detect and destroy metastasis. METHODS: The study was a retrospective cohort investigation. Patients with advanced ovarian cancer (stage III) undergoing cytoreductive surgery were stratified by the need for perioperative blood transfusion. Allogeneic transfusions were non-leucodepleted. Primary outcome included time to recurrence and survival. Data were extracted from the gynaecology oncology database at Northwestern University. Times to event outcomes were evaluated by constructing Kaplan-Meyer curves and Cox regression. RESULTS: The charts of 136 subjects were evaluated. Seventy-six received blood transfusion. Median [95% confidence interval (CI)] time to recurrence for the non-transfusion group was longer, i.e. 17 (6-27) months, compared to 11 (8-14) months for the transfused group (P = 0.03). Median (95% CI) survival following surgery was longer in the non-transfused group, i.e. 58 (43-73) months, compared to 36 (28-44) months for the transfused group (P = 0.04). Cox regression showed that transfused subjects had shorter median times to recurrence and mortality after adjusting for age and tumour grade. CONCLUSIONS: There is an association between ovarian cancer recurrence and allogeneic perioperative blood transfusion in patients with advanced ovarian cancer undergoing cytoreductive surgery. These findings may have important implications in the perioperative management of those patients.

Determination of residual antiplatelet activity of clopidogrel before neuraxial injections.

BACKGROUND: Guidelines recommend discontinuation of clopidogrel for 7 days before a neuraxial injection, while other directives suggest that 5 days might be adequate. We examined the time course of antiplatelet activity after clopidogrel discontinuation in patients undergoing epidural injections. METHODS: Thirteen patients were studied at baseline, 3, 5, and 7 days after discontinuation of clopidogrel. P(2)Y(12) determinations were performed using the VerifyNow(®) assay (Accumetrics, San Diego, CA, USA), and clot closure times with stimulation by collagen/epinephrine and collagen/adenosine diphosphate using the PFA-100(®) (Platelet Function Analyzer, Siemens Diagnostics, Deerfield, IL, USA). Repeated-measures ANOVA was used to evaluate P(2)Y(12) platelet reaction units, PFA-100 closure times, and per cent P(2)Y(12) inhibition values. Wilcoxon's signed-rank test was used to compare the frequencies of ≥30%, 11-29%, and ≤10% platelet inhibition between the baseline and subsequent sampling points after discontinuation of clopidogrel. RESULTS: On day 3 after clopidogrel discontinuation, two subjects had ≥30%, seven subjects had 11-29%, and four subjects had ≤10% platelet inhibition; the corresponding numbers were 0, 3, and 10 subjects on day 5 (P=0.04). There were no differences between the ≥30%, 11-29%, and <10% platelet inhibition groups between days 5 and 7 (0, 0, and 13 subjects, P=1.0). PFA-ADP closure times were normal throughout the study period except in one patient. CONCLUSIONS: These findings support the recommendation that discontinuation of clopidogrel for 5 days allows >70% of platelet function and might be adequate before a neuraxial injection is performed.

Dose ranging study on the effect of preoperative dexamethasone on postoperative quality of recovery and opioid consumption after ambulatory gynaecological surgery.

BACKGROUND: Glucocorticoids are commonly administered before ambulatory surgery, although their effects on quality of recovery are not well characterized. The purpose of this study was to evaluate the dose-dependent effects of dexamethasone on patient recovery using the Quality of Recovery 40 questionnaire (QoR-40) after ambulatory surgery. METHODS: This prospective, double-blind trial studied 106 female subjects undergoing outpatient gynaecological laparoscopy. Subjects were randomized to receive saline, dexamethasone 0.05 mg kg(-1) or dexamethasone 0.1 mg kg(-1) before induction. The primary outcome was global QoR-40 at 24 h. Postoperative pain, analgesic consumption, side-effects, and discharge time were also evaluated. RESULTS: Global median (IQR) QoR-40 after dexamethasone 0.1 mg kg(-1) 193 (192-195) was greater than dexamethasone 0.05 mg kg(-1) 179 (175-185) (P=0.004) or saline, 171 (160-182) (P<0.005). Median (IQR) morphine equivalents administered before discharge were 2.7 (0-6.3) mg after dexamethasone 0.1 mg kg(-1) compared with 5.3 (2.4-8.8) mg and 5.3 (2.7-7.8) mg after dexamethasone 0.05 mg kg(-1) and saline (P=0.02). Time to meet discharge criteria was 30 min shorter after dexamethasone 0.1 mg kg(-1) compared with saline (P=0.005). At 24 h, subjects receiving dexamethasone 0.1 mg kg(-1) had consumed less opioid analgesics, reported less sore throat, muscle pain, confusion, difficulty in falling asleep, and nausea compared with dexamethasone 0.05 mg kg(-1) and saline. CONCLUSIONS: Dexamethasone demonstrated dose-dependent effects on quality of recovery. Dexamethasone 0.1 mg kg(-1) reduced opioid consumption compared with dexamethasone 0.05 mg kg(-1), which may be beneficial for improving recovery after ambulatory gynaecological surgery.

Low-dose ketamine with multimodal postcesarean delivery analgesia: a randomized controlled trial.

BACKGROUND: Ketamine at subanesthetic doses has analgesic properties that have been shown to reduce postoperative pain and morphine consumption. We hypothesized that intravenous ketamine 10mg administered during spinal anesthesia for cesarean delivery, in addition to intrathecal morphine and intravenous ketorolac, would decrease the incidence of breakthrough pain and need for supplemental postoperative analgesia. METHODS: Using a randomized double-blind placebo-controlled design, healthy women scheduled for cesarean delivery receiving hyperbaric spinal bupivacaine, fentanyl and morphine were randomized to intravenous ketamine 10mg or saline following delivery. Postoperative analgesia included scheduled ketorolac and acetaminophen/hydrocodone tablets as needed for breakthrough pain. The primary outcome was the incidence of breakthrough pain in the first 24h. Secondary outcomes included the number of acetaminophen/hydrocodone tablets administered and numeric rating scale for pain (0-10). RESULTS: Group characteristics did not differ. There was no difference in the incidence of breakthrough pain (ketamine 75% VS. saline 74%, P=0.86). There was no difference in 24-h or 72-h use of supplemental acetaminophen/hydrocodone tablets between groups. Pain scores in the first 24h were similar, but lower in the ketamine compared to the saline group 2weeks postpartum (difference -0.6, 95% CI -1.1 to -0.9). CONCLUSIONS: We found no additional postoperative analgesic benefit of low-dose ketamine during cesarean delivery in patients who received intrathecal morphine and intravenous ketorolac. Subjects who received ketamine reported lower pain scores 2weeks postpartum.

The Berlin Questionnaire for assessment of sleep disordered breathing risk in parturients and non-pregnant women.

BACKGROUND: Pregnancy is associated with alteration in sleep patterns and quality. We wished to investigate whether pregnant women have a higher likelihood of a positive Berlin Questionnaire than non-pregnant women. METHODS: Pregnant women ages 18-45 years (n=4074) presenting for delivery, and non-pregnant women ages 18-45 years (n=490) presenting for outpatient surgery provided demographic information and completed the Berlin Questionnaire evaluating self-reported snoring and daytime sleepiness. For the pregnant patients, the infant's birth weight and Apgar scores were also recorded. RESULTS: Of the 1439 patients with a positive Berlin Questionnaire, 96 were in the non-pregnant control population versus 1343 in the pregnant population (20% vs. 33%, respectively, P<0.001; odds ratio 2.0 [95% CI: 1.6-2.5]). There was a positive correlation between infant weight and a positive Berlin Questionnaire. The incidence of preeclampsia was greater (odds ratio 3.9) in the pregnant patients with a positive Berlin Questionnaire as compared with the parturients with a negative Berlin Questionnaire (odds ratio 1.1). CONCLUSION: Parturients are more likely to have a positive Berlin Questionnaire than non-pregnant women. This may indicate an increased likelihood of sleep disordered breathing.

Detection of hypoventilation during deep sedation in patients undergoing ambulatory gynaecological hysteroscopy: a comparison between transcutaneous and nasal end-tidal carbon dioxide measurements.

BACKGROUND: Transcutaneous measurement of carbon dioxide (Tc(co(2))) provides a non-invasive estimation of arterial carbon dioxide (Pa(co(2))). Nasal capnography (Pe'(co(2))) is used to assess ventilation during monitored anaesthesia care (MAC) with sedation since it can readily detect apnoea. We compared the agreement between Tc(co(2)) and Pe'(co(2)) with Pa(co(2)) and the ability to detect hypercarbia in patients under deep sedation. METHODS: Forty healthy female subjects receiving deep sedation for hysteroscopy were studied. A Tc(co(2)) (TOSCA 500, Radiometer, Inc., Westlake, OH, USA) electrode was applied to the earlobe and Pe'(co(2)) capnography was monitored using nasal side-stream sampling. All subjects received oxygen (3 litre min(-1)). Subjects were evaluated at intervals using a modified Ramsay sedation score until they reached a score >or=5. Arterial blood gas values were compared with Tc(co(2)) and Pe'(co(2)) values. Bland-Altman, linear regression, and receiver operator characteristics analysis were performed. RESULTS: The mean (sd) absolute difference between the Tc(co(2)), Pe'(co(2)), and the Pa(co(2)) were 0.43 (0.35) and 1.06 (0.8) kPa, respectively (P=0.002). Tc(co(2)) demonstrated a mean bias (2 sd) of 0.23 (0.07-0.4) kPa with Pa(co(2)) compared with -0.93 (-1.24 to -0.63) kPa for Pe'(co(2)). One minute before blood sampling, the sensitivity of the Tc(co(2)) monitor for detecting Pa(co(2)) >6.65 kPa was greater than for Pe'(co(2)) (66.7% vs 33.3%, P<0.01). CONCLUSIONS: Tc(co(2)) demonstrated better agreement with Pa(co(2)) than Pe'(co(2)) for patients under MAC with deep sedation. Tc(co(2)) monitoring was more sensitive for detection of Pa(co(2)) >6.65 kPa than Pe'(co(2)).

Observational study of the effect of mu-opioid receptor genetic polymorphism on intrathecal opioid labor analgesia and post-cesarean delivery analgesia.

BACKGROUND: The purpose of this two-part prospective observational and blinded trial was to determine whether the single nucleotide polymorphism of the mu-opioid receptor gene (OPRM1:c.304A>G) modifies (1) the duration of intrathecal fentanyl labor analgesia and (2) supplemental analgesic requirements after intrathecal morphine analgesia following cesarean delivery. METHODS: Labor analgesia was initiated with intrathecal fentanyl 25 microg. Patients undergoing primary cesarean delivery under spinal anesthesia received intrathecal morphine 150 microg. The primary outcome variables were duration of intrathecal fentanyl analgesia in the labor study and the requirement for supplemental systemic analgesia in the cesarean study. Outcomes were compared between 304A homozygotes (group A) and 304A>G heterozygotes and 304G homozygotes (group G). RESULTS: The labor study included 190 participants and the post-cesarean study included 103 participants; 24% subjects carried the 304A>G allele. The median (95% CI) duration of intrathecal fentanyl analgesia was 70 min (62, 78) in group A and 63 min (50, 76) in group G (P = 0.54). There was no difference in the amount of supplemental oral morphine equivalents required to treat breakthrough pain within 72 h after intrathecal morphine between groups A and G (median [IQR] 68 mg (37, 97) and 75 mg (37, 90) respectively, P = 0.99) or in the duration of intrathecal morphine analgesia (P = 0.84). The incidence of pruritus was greater in group A. CONCLUSIONS: Using the two outcome parameters duration of analgesia and treatment for breakthrough pain, we did not find a simple association between intrathecal opioid analgesia and OPRM1 304A/G polymorphism.