The association between epidural labour analgesia and postpartum depression: a randomised controlled trial.

There is conflicting evidence regarding the association between epidural labour analgesia and risk of postpartum depression. Most previous studies were observational trials with limited ability to account for confounders. We aimed to determine if epidural analgesia was associated with a significant change in the incidence of postpartum depression in this randomised controlled trial. We enrolled women aged 21-50 years old with a singleton fetus ≥ 36 weeks gestation. Patients were advised regarding available labour analgesic modalities during enrolment (epidural block; intramuscular pethidine; nitrous oxide; or intravenous remifentanil). On request for analgesia, patients were offered the modality that they had been allocated randomly to first. Blinded investigators recorded patient and obstetric characteristics within 24 h of delivery and assessed for postpartum depression at 6-10 weeks following delivery using the Edinburgh Postnatal Depression Scale (score ≥ 13 considered positive for postpartum depression). The modified intention-to-treat population consisted of all patients who received any form of labour analgesia, while per-protocol consisted of patients who received their randomised modality as their first form of labour analgesia. Of 881 parturients allocated randomly (epidural n = 441, non-epidural n = 440), we analysed 773 (epidural n = 389, non-epidural n = 384); 62 (15.9%) of women allocated to epidural group developed postpartum depression compared with 65 (16.9%) women allocate to the non-epidural group. There were no significant differences in the incidence of postpartum depression between the two groups (adjusted risk difference (95%CI) 1.6 (-3.0-6.3%), p = 0.49). Similar results were obtained with per-protocol analysis (adjusted risk difference (95%CI) -1.0 (-8.3-6.3%), p = 0.79). We found no significant difference in the risk of postpartum depression between patients who received epidural labour analgesia and those who utilised non-epidural analgesic modalities.

Risk factors for persistent pain after breast cancer surgery: a multicentre prospective cohort study.

Identifying factors associated with persistent pain after breast cancer surgery may facilitate risk stratification and individualised management. Single-population studies have limited generalisability as socio-economic and genetic factors contribute to persistent pain development. Therefore, this prospective multicentre cohort study aimed to develop a predictive model from a sample of Asian and American women. We enrolled women undergoing elective breast cancer surgery at KK Women's and Children's Hospital and Duke University Medical Center. Pre-operative patient and clinical characteristics and EQ-5D-3L health status were recorded. Pain catastrophising scale; central sensitisation inventory; coping strategies questionnaire-revised; brief symptom inventory-18; perceived stress scale; mechanical temporal summation; and pressure-pain threshold assessments were performed. Persistent pain was defined as pain score ≥ 3 or pain affecting activities of daily living 4 months after surgery. Univariate associations were generated using generalised estimating equations. Enrolment site was forced into the multivariable model, and risk factors with p < 0.2 in univariate analyses were considered for backwards selection. Of 210 patients, 135 (64.3%) developed persistent pain. The multivariable model attained AUC = 0.807, with five independent associations: age (OR 0.85 95%CI 0.74-0.98 per 5 years); diabetes (OR 4.68, 95%CI 1.03-21.22); pre-operative pain score at sites other than the breast (OR 1.48, 95%CI 1.11-1.96); previous mastitis (OR 4.90, 95%CI 1.31-18.34); and perceived stress scale (OR 1.35, 95%CI 1.01-1.80 per 5 points), after adjusting for: enrolment site; pre-operative pain score at the breast; pre-operative overall pain score at rest; postoperative non-steroidal anti-inflammatory drug use; and pain catastrophising scale. Future research should validate this model and evaluate pre-emptive interventions to reduce persistent pain risk.

Prediction of breakthrough pain during labour neuraxial analgesia: comparison of machine learning and multivariable regression approaches.

INTRODUCTION: Risk-prediction models for breakthrough pain facilitate interventions to forestall inadequate labour analgesia, but limited work has used machine learning to identify predictive factors. We compared the performance of machine learning and regression techniques in identifying parturients at increased risk of breakthrough pain during labour epidural analgesia. METHODS: A single-centre retrospective study involved parturients receiving patient-controlled epidural analgesia. The primary outcome was breakthrough pain. We randomly selected 80% of the cohort (training cohort) to develop three prediction models using random forest, XGBoost, and logistic regression, followed by validation against the remaining 20% of the cohort (validation cohort). Area-under-the-receiver operating characteristic curve (AUC), sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were used to assess model performance. RESULTS: Data from 20 716 parturients were analysed. The incidence of breakthrough pain was 14.2%. Of 31 candidate variables, random forest, XGBoost and logistic regression models included 30, 23, and 15 variables, respectively. Unintended venous puncture, post-neuraxial analgesia highest pain score, number of dinoprostone suppositories, neuraxial technique, number of neuraxial attempts, depth to epidural space, body mass index, pre-neuraxial analgesia oxytocin infusion rate, maternal age, pre-neuraxial analgesia cervical dilation, anaesthesiologist rank, and multiparity, were identified in all three models. All three models performed similarly, with AUC 0.763-0.772, sensitivity 67.0-69.4%, specificity 70.9-76.2%, PPV 28.3-31.8%, and NPV 93.3-93.5%. CONCLUSIONS: Machine learning did not improve the prediction of breakthrough pain compared with multivariable regression. Larger population-wide studies are needed to improve predictive ability.

Association of renin-angiotensin-aldosterone system genetic polymorphisms with maternal hypotension during spinal anaesthesia for caesarean delivery: a retrospective cohort study.

BACKGROUND: Unless prevented, hypotension occurs in up to 80% of normotensive women undergoing spinal anaesthesia for caesarean delivery. Renin-angiotensin-aldosterone system genetic polymorphisms have been associated with hypertensive disease, but few studies investigated effects on blood pressure regulation under spinal anaesthesia. We postulated that these polymorphisms increased vasodilation and maternal hypotension during spinal anaesthesia. METHODS: A retrospective secondary analysis of data from four prospective trials with similar inclusion/exclusion criteria evaluating phenylephrine/ephedrine delivery systems during spinal anaesthesia for elective caesarean delivery. Angiotensin type-1 receptor (AT1R) (A1166C), angiotensin-converting enzyme (ACE) (I/D), and aldosterone synthase CYP11B2 (C344T) polymorphisms were identified from stored specimens. The associations between the polymorphisms and hypotension (systolic blood pressure <80% of baseline), and vasopressor use, were determined by univariable and multivariable regression. RESULTS: Of 556 patients, 378 (68.0%) had hypotension. The AC/CC genotypes of AT1R (A1166C) were associated with hypotension by univariable analysis (OR 2.70, 95% CI 1.38 to 5.28, P=0.004]) and multivariable analysis (OR 3.65, [95% CI 1.68 to 7.94, P=0.004]) after adjustment for age, race, intravenous fluid volume, and block height. No difference in vasopressor use or adverse maternal or fetal outcomes were noted. Baseline characteristics were similar, with the exception of higher baseline blood pressure, block height, and intravenous fluid volume in the hypotensive group. There was no significant association between ACE and CYP11B2 polymorphisms and hypotension. CONCLUSION: AC/CC genotypes of AT1R (A1166C) polymorphism were associated with maternal hypotension under spinal anaesthesia for caesarean delivery. An association with cardiovascular indices and high-risk parturients should be examined.

A case series of vital signs-controlled, patient-assisted intravenous analgesia (VPIA) using remifentanil for labour and delivery.

Intravenous remifentanil patient-controlled analgesia can be used during labour as an alternative to epidural analgesia. Adverse effects of opioids, including hypoxia and bradycardia, may lead to maternal morbidity and mortality. We devised an interactive feedback system based on a clinical proportional algorithm, to continuously monitor for adverse effects to enhance safety and better titrate analgesia. This vital signs-controlled, patient-assisted intravenous analgesia with remifentanil used a prototype delivery system linked to a pulse oximeter that evaluated maternal oxygen saturation and heart rate continuously. With this system, we detected oxygen saturation < 95% for more than 60 s in 15 of 29 subjects (52%); and heart rate < 60 min-1 for more than 60 s in 7 of 29 subjects (24%) during use. The system automatically responded appropriately by reducing the dosages and temporarily halting remifentanil administration, thus averting further hypoxia and bradycardia.

Closed-loop double-vasopressor automated system vs manual bolus vasopressor to treat hypotension during spinal anaesthesia for caesarean section: a randomised controlled trial.

Hypotension necessitating vasopressor administration occurs commonly during caesarean section under spinal anaesthesia. We developed a novel vasopressor delivery system that automatically administers phenylephrine or ephedrine based on continuous non-invasive arterial pressure monitoring. A phenylephrine bolus of 50 µg was given at 30-s intervals when systolic blood pressure fell < 90% of baseline; an ephedrine bolus of 4 mg was given instead if systolic pressure fell < 90% of baseline together with a heart rate < 60 beats.min(-1). The control group used manual boluses of either phenylephrine 100 µg or ephedrine 8 mg, administered at 1-min intervals based on the same thresholds for systolic pressure and heart rate. This randomised, controlled, double-blinded trial involved 213 healthy women who underwent elective caesarean delivery under spinal anaesthesia using 11 mg hyperbaric bupivacaine with 15 µg fentanyl and 100 µg morphine. The automated vasopressor group had better systolic pressure control, with 37/106 (34.9%) having any beat-to-beat systolic pressure reading < 80% of baseline compared with 63/107 (58.9%) in the control group (p < 0.001). There was no difference in the incidence of reactive hypertension, defined as systolic pressure > 120% of baseline, with 8/106 (7.5%) in the automated vasopressor group vs 14/107 (13.1%) in the control group, or total dose of vasopressors. The automated vasopressor group had lower median absolute performance error of 8.5% vs control of 9.8% (p = 0.013), and reduced incidence of nausea (1/106 (0.9%) vs 11/107 (10.3%), p = 0.005). Neonatal umbilical cord pH, umbilical lactate and Apgar scores were similar. Hence, our system afforded better control of maternal blood pressure and reduced nausea with no increase in reactive hypertension when compared with manual boluses.

Ruptured uterine artery pseudoaneurysm: an overlooked cause of late postpartum haemorrhage.

We report an exceptional case of secondary postpartum hemorrhage (PPH) twenty days after cesarean delivery, resulting from a ruptured uterine artery pseudoaneurysm (UAP). The diagnosis was initially confounded by a septic shock necessitating inotropic support in the intensive care unit. Intense vaginal bleeding occurred eleven days after uterine curettage. Doppler ultrasound showed an anechoic focus in the inferior part of the uterus with turbulent flow. Bilateral internal iliac artery angiograms revealed a left uterine artery pseudoaneurysm that was successfully embolized. UAP is a rare cause of unexplained PPH that requires a high index of suspicion for diagnosis. This first report in the anesthesia literature serves to focus our awareness on its possible occurrence, and gives track to its management. Pitfalls in UAP diagnostic are highlighted (delayed presentation, possibility of spontaneous hemostasis, and lack of typical findings on colour Doppler sonography in hypotensive patients). These pitfalls may further be confounded by a concomitant sepsis. Angiography and selective uterine artery embolization is the treatment of choice.

Closed-loop double-vasopressor automated system to treat hypotension during spinal anaesthesia for caesarean section: a preliminary study.

Hypotension occurs in most caesarean sections under spinal anaesthesia, necessitating vasopressor administration. However, the optimal dosing regimen remains unclear. We have developed a novel vasopressor delivery system that automatically administers phenylephrine or ephedrine based on continuous non-invasive blood pressure monitoring. This prospective cohort study recruited 55 healthy women under standardised spinal anaesthesia with 2.2 ml hyperbaric bupivacaine 0.5%, 15 µg fentanyl and 100 µg morphine. A 50-µg phenylephrine bolus was given at 1-min intervals when systolic blood pressure fell below 90% of baseline, and a 4-mg ephedrine bolus was given when hypotension developed with bradycardia (heart rate <60 beats.min(-1) ). Systolic blood pressure was within 20% of baseline in 88% of all measurements. Six patients (11%) had one or more measurements above 120% of baseline (1% of all measurements), whereas 36 (65%) had at least one reading below 80% of baseline (11% of total measurements). The system maintained systolic blood pressure at a mean (SD) of -9.1 (7.0)% below baseline, with 5.4 (2.5)% fluctuation. Two patients (4%) experienced pre-delivery nausea. All 5-min Apgar scores were 9.

Comparison of the LMA Supreme vs the i-gel in paralysed patients undergoing gynaecological laparoscopic surgery with controlled ventilation.

We compared the efficacy of the inflatable cuff of the LMA Supreme against the non-inflatable i-gel cuff in providing an adequate seal for laparoscopic surgery in the Trendelenburg position in 100 female patients. There was no difference in our primary outcome, oropharyngeal leak pressure, between the LMA Supreme and the i-gel (mean (SD) 26.4 (5.1) vs 25.0 (5.7) cmH(2) O, respectively; p = 0.18). Forty-seven (94%) LMA Supremes and 48 (96%) i-gels were successfully inserted on the first attempt, with similar ease, and comparable times to the first capnograph trace (mean (SD) 14.3 (4.7) s for the LMA Supreme vs 15.4 (8.2) s for the i-gel; p = 0.4). Gastric tube insertion was easier and achieved more quickly with the LMA Supreme vs the i-gel (9.0 (2.5) s vs 15.1 (7.3) s, respectively; p < 0.001). After creation of the pneumoperitoneum, there was a smaller difference between expired and inspired tidal volumes with the LMA Supreme (21.5 (15.2) ml) than with the i-gel (31.2 (23.5) ml; p = 0.009). There was blood on removal of two LMA Supremes and one i-gel. Four patients in the LMA Supreme group and one patient in the i-gel group experienced mild postoperative sore throat.

Comparison of three videolaryngoscopes: Pentax Airway Scope, C-MAC, Glidescope vs the Macintosh laryngoscope for tracheal intubation.

We compared the intubating characteristics of the Pentax Airway Scope, the C-MAC and the Glidescope with those of the Macintosh laryngoscope in 400 patients without predictors of difficult intubation. We found shorter intubation times with the Airway Scope (mean (SD) 20.6 (11.5) s) compared with the C-MAC (31.9 (17.6) s) and Glidescope (31.2 (15.0) s), p < 0.001. The median (IQR [range]) score for ease of intubation was significantly lower (better) with the Airway Scope (0 (0-8.75 [0-60])) than with the C-MAC (10 (0-20 [0-90])) or Glidescope (0 (0-20 [0-80])), p < 0.001. Ease of blade insertion in the C-MAC (0 (0-0 [0-30])) was superior to that of the Airway Scope (0 (0-0 [0-70])), Macintosh (0 (0-0 [0-80])) or Glidescope (0 (0-10 [0-60])), p = 0.006. More patients had a grade 1 laryngeal view with the Airway Scope (97%) compared with the C-MAC (87%), Glidescope (78%), or Macintosh (58%), p < 0.001. There were no grade 3 laryngeal views with the Airway Scope. The three videolaryngoscopes had comparable first attempt successful intubation rates: 95% for the Airway Scope, 93% for the C-MAC and 91% for the Glidescope.

A randomised controlled trial of hyperbaric bupivacaine with opioids, injected as either a mixture or sequentially, for spinal anaesthesia for caesarean section.

It is common practice to mix opioids with hyperbaric bupivacaine in a single syringe before intrathecal injection of the mixture. Mixing these drugs may alter the density of the hyperbaric solution, affecting the spread of local anaesthetic and opioid. Forty-eight women having elective caesarean section under spinal anaesthesia were recruited to this double-blind, randomised trial. Group M (n=24) received 2 ml of 0.5% hyperbaric bupivacaine plus morphine 100 microg plus fentanyl 15 microg, mixed in a syringe prior to administration. Group S (n=24) received 2 ml of 0.5% bupivacaine through one syringe, followed by morphine 100 microg plus fentanyl 15 microg through a separate syringe. All patients received patient-controlled intravenous morphine for 24 hours postoperatively. Block characteristics, postoperative pain scores and morphine use were noted. The patients in Group M had higher levels of sensory block to cold than those in Group S (median T2 vs. T3) (P = 0.003). Five patients in Group M and none in Group S had a block to cold > or = T1 (P = 0.02). There was no difference between groups in the incidence of hypotension, need for vasopressor or side-effects. Morphine consumption was significantly higher in group M (13.3 +/- 11.2 vs. 6.2 +/- 7.2 mg, P = 0.015). Mixing of fentanyl and morphine with hyperbaric bupivacaine results in a higher level of sensory block than sequential administration of bupivacaine then opioid and may be associated with higher postoperative opioid requirement.

The use of ProSeal laryngeal mask airway in caesarean section--experience in 3000 cases.

Rapid sequence induction is currently the recommended technique in general anaesthesia for caesarean section. However, the usefulness of the ProSeal laryngeal mask airway as a rescue airway in the event of difficult or failed intubation has been recognised in numerous case reports. In this study, we report the experience of the use of the ProSeal laryngeal mask in 3000 elective caesarean sections in a single centre, using a method of insertion that allows a rapid establishment of a patent airway together with gastric drainage.

A prospective, randomised, cross-over trial comparing the EndoFlex and standard tracheal tubes in patients with predicted easy intubation.

We aimed to determine if using the EndoFlex tracheal tube on the first intubation attempt provided improved placement times and intubation success compared with a standard-type tracheal tube in 50 patients undergoing gynaecological surgery in a prospective, randomised, cross-over trial. We found that using the EndoFlex resulted in shorter intubation times (mean (SD) 14.8 (9.7) vs 30.1 (30.5) s), easier intubation (VAS, median (range) 10 (0-70) vs 20 (0-100)), and an increased rate of successful insertion at the first attempt; all p < 0.001. Flexing the distal tip of the EndoFlex was used in 18 patients. There were reductions in the use of external laryngeal pressure, advancement of laryngoscope blade and increased lifting force when intubating with the EndoFlex. Furthermore, patients with a grade 2 (19/50) or 3 (6/50) laryngoscopic view had shorter intubation times, easier intubation and reduced insertion attempts with the EndoFlex. The EndoFlex is a satisfactory alternative to a standard-type tracheal tube, even with an anterior larynx.

Randomised comparison of Pentax AirwayScope and Glidescope for tracheal intubation in patients with normal airway anatomy.

SUMMARY: We compared intubating characteristics of the Pentax AirwayScope and Glidescope in a randomised controlled trial involving 140 patients. We found significantly shorter intubation times with mean (SD) 21.3 (12.3) vs 30.2 (13.2) s, lower intubating difficulty scores 4.4 (10.4) vs 12.8 (16.3) p < 0.001, and better grade 1 laryngeal views with the Pentax AirwayScope (95.7 vs 81.4%, p = 0.015). Significantly more optimisation manoeuvres were needed to successfully intubate with the Glidescope, with significant inability to align the tip of the tracheal tube with the glottic opening with the Glidescope in 9 (13%) vs no patients, p = 0.013. There was more mucosal bleeding (4 (5.7%) vs 1 (1.4%), p = 0.366), more lip bleeding (3 (4.3%) vs 1 (1.4%), p = 0.620) and significantly more postoperative sorethroat, 13 (18.6%) vs 0, p < 0.001 associated with the Glidescope.

Incidence and risk factors for chronic pain after caesarean section under spinal anaesthesia.

This study investigated the incidence and risk factors associated with chronic pain after elective caesarean section under spinal anaesthesia in an Asian population. A prospective cohort study was conducted among subjects who underwent elective caesarean section under spinal anaesthesia, with morphine patient-controlled analgesia administered for 24 hours postoperatively. Perioperative, surgical and obstetric factors were investigated prospectively. Phone surveys were conducted to identify risk factors associated with chronic pain. A total of 857 subjects completed both the perioperative study and phone survey. The incidence of wound scar pain for three months after surgery was 9.2% (79). Of the 51 subjects with persistent pain at the time of subsequent survey, 9.8% (n = 5) had constant pain, 9.8% (n = 5) had daily pain and 23.5% (n = 12) had pain intermittently, at an interval of days. The independent risk factors for development of chronic pain were higher pain scores recalled in the immediate postoperative period (odds ratio [OR, 95% confidence interval] 1.348 [1.219 to 1.490], P = 0.0001), pain present elsewhere (OR 2.471 [1.485 to 4.112], P = 0.001) and non-private insurance status (OR 1.679 [1.034 to 2.727], P = 0.036). The two most common sites of pain other than wound pain were back pain (n = 316) and migraine (n = 87).

Comparison of the single-use LMA supreme with the reusable ProSeal LMA for anaesthesia in gynaecological laparoscopic surgery.

The Laryngeal Mask Airway Supreme (LMAS) is a new, single-use laryngeal mask airway with gastric access. We conducted a randomised controlled study comparing the LMAS with the reusable ProSeal Laryngeal Mask Airway (PLMA) in 70 patients undergoing general anaesthesia with paralysis for gynaecological laparoscopic surgery. Our primary outcome measure was the oropharynegal leak pressure. We also compared the two devices for ease of insertion, adequacy of ventilation and incidence of complications. Both devices had similar rates of successful insertion at the first attempt (LMAS 94% vs PLMA 91%). There was no difference in the time to establish an effective airway (LMAS 25 +/- 22 vs PLMA 24 +/- 9 seconds), although gastric tube insertion was faster for the LMAS (5 +/- 1 vs 7 +/- 3 seconds, P < 0.001). The mean oropharyngeal leak pressure in the LMAS was significantly lower than in the PLMA (27.9 +/- 4.7 vs 31.7 +/- 6.3 cmH2O, P = 0.007). This was consistent with a lower maximum tidal volume achieved with the LMAS (481 +/- 76 vs 515 +/- 63 ml, P = 0.044). We found that after 60 minutes the cuff pressure was significantly higher in the PLMA (110 +/- 21 vs 57 +/- 8 cmH2O, P < 0.001). There was no difference in the ability to provide adequate ventilation and oxygenation during anaesthesia. Complication rates were similar We conclude that the oropharyngeal leak pressure and the maximum achievable tidal volume are lower with the LMAS than with the PLMA.

An observational prospective cohort study of incidence and characteristics of failed spinal anaesthesia for caesarean section.

BACKGROUND: A prospective cohort study was performed in 800 parturients undergoing elective caesarean section under spinal anaesthesia from May 2005 to April 2006 in a large maternity hospital in Singapore, in order to determine the incidence of and risk factors for total and partial failure of spinal anaesthesia. METHODS: A routine single-shot spinal technique using intrathecal 0.5% heavy bupivacaine 2.0 mL (10 mg) and morphine 100 microg was administered with a 27-gauge Whitacre spinal needle via a 20-gauge introducer. Demographic, surgical and anaesthetic data were collected to determine risk factors for failure of spinal anaesthesia. RESULTS: Incidence of total failure requiring conversion to general anaesthesia was 0.5% (4 cases) in which three cases had inadequate block (loss of sensation to cold less than T6) and one case had no sensory block. Thirty-three parturients (4.1%) required intravenous fentanyl and seven (0.9%) required Entonox for intraoperative analgesic supplementation. Postpartum sterilization (P<0.001) was an independent risk factor for partial failure requiring intravenous fentanyl and Entonox. CONCLUSION: Spinal anaesthesia using bupivacaine 10 mg with morphine 100 microg produces reliable anaesthesia for elective caesarean section. Postpartum sterilization involves exteriorisation of the uterus with additional surgical manipulation and hence may necessitate analgesic supplementation. The initial use of a combined spinal-epidural technique or the addition of intrathecal fentanyl or clonidine or an increased dose of local anaesthetic may be considered to decrease the incidence of intraoperative pain.

Tracheal intubating conditions using propofol and remifentanil target-controlled infusion: a comparison of remifentanil EC50 for Glidescope and Macintosh.

BACKGROUND AND OBJECTIVE: The combination remifentanil-propofol was used for tracheal intubation without muscle relaxant in patients with anticipated difficult airway. Using a target-controlled infusion, we compared the remifentanil concentrations required for intubation with the Macintosh laryngoscope and the Glidescope, at a constant plasma concentration of propofol without muscle relaxant. METHODS: Sixty ASA I or II patients were randomly assigned to either the Macintosh or Glidescope group (30 per group). A target-controlled infusion of propofol was used to maintain a predetermined effect-site concentration of 3 microg ml. The target concentration of remifentanil for each patient in a group was determined by the response of the previous patient, using increments or decrements of 0.5 ng ml. Intubation was attempted at 4 min following induction to allow for equilibration between the blood and the effect site. The intubation response was graded as successful or failure by the Helbo-Hansen scoring system. The median effective concentration of remifentanil for tracheal intubation was determined using the probit regression model. RESULTS: The median effective concentration of remifentanil required for intubation with the Macintosh laryngoscope was 4.41 ng ml (3.13-5.27; 95% confidence interval) and that of the Glidescope was 5.45 ng ml (4.45-6.45; 95% confidence interval; P = 0.083). There was no difference in the total intubation scores. No patients showed signs of muscle rigidity. Arterial pressures or heart rate did not differ between the groups. CONCLUSION: There is no strong evidence that the target remifentanil concentrations required for adequate intubating conditions differed according to the technique used for intubation in the nonparalysed patient. We did not detect any major complications using this technique for either method.

Comparison of computer-integrated patient-controlled epidural analgesia and patient-controlled epidural analgesia with a basal infusion for labour and delivery.

Computer-integrated patient-controlled epidural analgesia (CIPCEA) is a novel epidural drug delivery system. It automatically adjusts the background infusion based on the individual parturient's need for analgesia as labour progresses. In this randomised controlled trial, we compared the local anaesthetic consumption by parturients using either CIPCEA or patient-controlled epidural analgesia with a moderate basal infusion (PCEABI) of 5 ml/hour. We recruited 60 parturients after receiving ethics committee approval. Group CIPCEA (n = 30) received a similar patient-controlled epidural analgesia regimen but the computer integration titrated the background infusion to 5, 10 or 15 ml/hour if the patient required respectively one, two or three demand boluses in the previous hour. The background infusion was decreased by 5 ml/hour if there was no demand in the previous hour. Group PCEABI received patient-controlled epidural analgesia with a basal infusion of 5 ml/hour. The sample size was calculated to show equivalence in local anaesthetic use. The time-weighted consumption of local anaesthetic was similar in both groups (mean difference 0.3 mg/hour 95% confidence interval: -1.8, 1.3, P = 0.755). The CIPCEA group had higher maternal satisfaction scores: mean (SD) 94.8 (6.32) vs. 85.5 (9.41), P = 0.0001. The CIPCEA group had a higher infusion rate during the second stage of labour (mean (SD) 7.0 (4.1) ml/hour vs. 4.5 (1.5) ml/hour P = 0.008), but did not have a longer duration of this stage. There were no differences between the groups in obstetric or foetal outcomes or side-effect profiles. The CIPCEA system has similar time-weighted, hourly consumption of local anaesthetic to PCEABI and may increase patient satisfaction.