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.

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.

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.

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.

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.

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.

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.

Analgesic efficacy using loss of resistance to air vs. saline in combined spinal epidural technique for labour analgesia

Identification of the epidural space is often performed using the loss of resistance technique to either air or saline. We sought to investigate if the medium used affected the quality of analgesia obtained by parturients who received labour epidurals. We conducted a retrospective audit of labour epidurals performed on nulliparous parturients in our institution from May 2003 to March 2005. All epidural catheters were inserted by senior obstetric anaesthetists using a combined spinal epidural technique. The following information was recorded: parturients' demographic data, loss of resistance technique used, type and amount of local anaesthetic solution administered, complications encountered during procedure, pre-block and post-block pain scores, incidence of breakthrough pain requiring supplemental medication and post-block side-effects. Data from 2848 patients were collected and analysed; 56% of patients made up the saline group and 44% the air group. Patients in both groups had similar demographic profiles and similar incidences of complications and post-block side-effects. However patients in the air group had a higher incidence of recurrent breakthrough pain P = 0.023). We also identified three other factors that were associated with an increased incidence of recurrent breakthrough pain; administration of pre-block oxytocin, sitting position of the parturient during the procedure and the use of intrathecal bupivacaine for induction of analgesia. Our findings suggest that a loss of resistance to air is associated with a higher incidence of recurrent breakthrough pain among parturients who received combined spinal epidural analgesia for labour than a loss of resistance to saline.

Comparison of 2% Lignocaine with Adrenaline and Fentanyl, 0.75% Ropivacaine and 0.5% Levobupivacaine for Extension of Epidural Analgesia for Urgent Caesarean Section after Low Dose Epidural Infusion during Labour

Low dose local anaesthetic and fentanyl epidural solutions are commonly ‘topped-up’ for urgent caesarean section. However, the block characteristics associated with newer local anaesthetics such as ropivacaine 0.75% and levobupivacaine 0.5% have not been fully determined. In a randomised double-blinded controlled clinical trial, we compared 2% lignocaine with adrenaline and fentanyl (LAF), 0.75% ropivacaine and 0.5% levobupivacaine for extension of low dose epidural analgesia for urgent caesarean section in 90 Asian parturients.

There was no significant difference in the median, interquartile range, time to T4 loss of sensation to cold between LAF (9.5, 7.0 to 13.3 minutes), 0.75% ropivacaine (10.0, 7.0 to 15.0 minutes) and 0.5% levobupivacaine (10.0, 7.0 to 15.0 minutes). No woman required conversion to general anaesthesia. The supplementation rate did not differ between groups. Levobupivacaine provided a longer duration of sensory block compared to LAF, but a similar duration to 0.75% ropivacaine.

Under the conditions of this study there was no significant difference in time to surgical readiness (defined as loss of sensation to cold to T4) between LAF, 0.75% ropivacaine and 0.5% levobupivacaine groups. Ropivacaine and levobupivacaine are suitable alternatives for extending epidural analgesia for urgent caesarean section.

Ergometrine Administration for Postpartum Haemorrhage in an Undiagnosed Pre-Eclamptic

We report a case of a parturient who was well antenatally but presented with oliguria following delivery. The possibility of postpartum preeclampsia was obscured by simultaneous postpartum haemorrhage. Ergometrine was given and she suffered an eclamptic seizure shortly after. We discuss the diagnostic difficulties presented by simultaneous presentation of postpartum preeclampsia and haemorrhage and the likelihood that ergometrine precipitated eclampsia in a patient at risk. While ergometrine is an effective drug for the management of uterine atony, its potential role in precipitating eclampsia must be considered.

Automated regular boluses for epidural analgesia: a comparison with continuous infusion

BACKGROUND

Intermittent epidural bolus dosing is a method of drug delivery that can prolong the duration of labour analgesia induced by a combined spinal epidural (CSE). In this randomized, double-blinded study, we compared the analgesic efficacy of two drug delivery systems: regular intermittent epidural boluses and continuous epidural infusion and assessed the incidence of breakthrough pain after CSE.

METHODS

With the approval of the Hospital Ethics Committee, we recruited 60 parturients into this randomized controlled trial. A CSE was performed with intrathecal fentanyl 25 mug in all patients. The parturients were then randomly allocated into two groups. The infusion group received a continuous epidural infusion of levobupivacaine 0.1% with fentanyl 2 microg/mL at a rate of 10 mL/h. The bolus group received 5-mL epidural boluses every half hour. The sample size was computed to detect a 40% reduction in the rate of breakthrough pain.

RESULTS

The bolus group had a lower incidence of breakthrough pain than the infusion group (10% vs. 37%, P < 0.05). The bolus group also had significantly higher satisfaction scores for labour analgesia: 97+/-8 (mean+/-SD) vs. 89+/-7 (P < 0.05).

CONCLUSION

Automated regular bolus delivery of epidural analgesia when compared with continuous infusion decreased the incidence of breakthrough pain and increased maternal satisfaction. In a busy obstetric unit, this may also serve to decrease the anesthetists' workload.

Rates of caesarean section and instrumental vaginal delivery in nulliparous women after low concentration epidural infusions or opioid analgesia: systematic review

OBJECTIVE

To compare the effects of low concentration epidural infusions of bupivacaine with parenteral opioid analgesia on rates of caesarean section and instrumental vaginal delivery in nulliparous women.

DATA SOURCES

Medline, Embase, the Cochrane controlled trials register, and handsearching of the International Journal of Obstetric Anesthesia.

STUDY SELECTION

Randomised controlled trials comparing low concentration epidural infusions with parenteral opioids.

DATA SYNTHESIS

Seven trials fulfilled the inclusion criteria for meta-analysis. Epidural analgesia does not seem to be associated with an increased risk of caesarean section (odds ratio 1.03, 95% confidence interval 0.71 to 1.48) but may be associated with an increased risk of instrumental vaginal delivery (2.11, 0.95 to 4.65). Epidural analgesia was associated with a longer second stage of labour (weighted mean difference 15.2 minutes, 2.1 to 28.2 minutes). More women randomised to receive epidural analgesia had adequate pain relief, with fewer changing to parenteral opioids than vice versa (odds ratio 0.1, 0.05 to 0.22).

CONCLUSIONS

Epidural analgesia using low concentration infusions of bupivacaine is unlikely to increase the risk of caesarean section but may increase the risk of instrumental vaginal delivery. Although women receiving epidural analgesia had a longer second stage of labour, they had better pain relief.

The effect of 10 degrees head-up tilt in the right lateral position on the systemic blood pressure after subarachnoid block for Caesarean section

Forty women presenting for elective Caesarean section under spinal anaesthesia were randomly assigned to have anaesthesia induced in the right lateral position either in the horizontal position or with 10 degrees head-up tilt. Hyperbaric bupivacaine 2 ml 0.5% with 0.1 mg of morphine was injected intrathecally before the parturients were placed in the supine position with 15 degrees left lateral tilt. Blood pressure and heart rate were monitored every minute and the sensory level (loss of sharp sensation to pinprick) was monitored every 3 min until clamping of the umbilical cord. Ephedrine 6 mg was given every minute that the systolic blood pressure decreased below 90 mmHg. The mean systolic blood pressure during the first 5 min after induction of spinal anaesthesia was lower in the control group compared to the tilted group (99 mmHg vs. 109 mmHg; p = 0.043). The upper limit of block was higher in the control group compared to the tilted group (p = 0.002). The use of 10 degrees head-up tilt resulted in a reduced incidence of hypotension initially and less extensive sensory block.