The impact of a transversus abdominis plane block including clonidine vs. intrathecal morphine on nausea and vomiting after caesarean section: A randomised controlled trial.

BACKGROUND: Intrathecal morphine (ITM) is a widely used technique for postcaesarean section analgesia but entails a high risk of postoperative nausea and vomiting (PONV). The transversus abdominis plane (TAP) block is an alternative. OBJECTIVE: We tested the hypothesis that a TAP block including clonidine reduces the incidence of PONV after caesarean section when compared with ITM. DESIGN: A randomised, controlled, double-blinded study. SETTING: Geneva University Hospitals, Switzerland, from October 2013 to February 2017. PATIENTS: A total of 182 patients undergoing elective caesarean section were studied. Reasons for noninclusion were complicated pregnancy, contraindication to spinal anaesthesia or TAP block, extreme weight or height, allergy to any medication or previous median abdominal incision. INTERVENTIONS: Patients were allocated randomly to one of two groups (quadruple blinded): 100 µg of morphine added to the spinal local anaesthetic or a bilateral TAP block with 20 ml of ropivacaine 0.375% + 75 µg of clonidine on each side. MAIN OUTCOME MEASURES: The primary outcome measure was the total number of patients presenting with PONV at 24 h. Secondary aims were to compare other adverse effects (pruritus, respiratory depression, hypotension, bradycardia, sedation), analgesic efficacy and the quality of postoperative recovery. RESULTS: At 24 h, there was no significant difference between ITM and TAP groups in the total number of patients presenting with PONV: 17/92 patients (18.5%, 95% confidence interval 11.1 to 27.9) and 27/88 patients (30.7%, 95% confidence interval 21.3 to 41.4) in TAP and ITM groups, respectively (P = 0.065). Pain scores at 6 h and cumulative morphine consumption at 24 h were lower in the ITM group (P < 0.0001 for morphine consumption at 24 h). The incidence of hypotension was higher in the TAP group (54.3 vs. 29.2%, P = 0.0006). Maternal satisfaction was high and not different between groups. CONCLUSION: A TAP block with clonidine and local anaesthetic does not reduce significantly the incidence of PONV compared with ITM. We confirm the superiority of ITM on acute postcaesarean section analgesia compared with a TAP block, even with clonidine as an adjunct. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01931215.

Development of a Simple Preoperative Risk Score for Persistent Pain After Breast Cancer Surgery: A Prospective Observational Cohort Study.

OBJECTIVES: Persistent postoperative pain is reported by 30% to 50% of patients following breast cancer surgery. Studies testing preventive measures, however, have so far failed to produce consistent positive results. If preventive measures could be targeted to a subgroup of patients at high risk of persistent pain, positive results would be more likely. Our aim was to develop a simple risk score predicting persistent pain after breast cancer surgery. MATERIALS AND METHODS: In a prospective observational cohort study, we tested the predictive ability of a 4 simple items score for persistent pain in 200 patients scheduled for breast cancer surgery. A multivariable logistic regression model was created for the outcome of clinically important pain at 4 months. RESULTS: On the basis of literature review and univariable analysis of our data, 4 parameters were selected: preoperative pain at the surgical site, history of depression, age below 50 years and expected pain of high intensity (>6/10). Points for the score are based on the coefficients of the logistic regression model. A total score ≥2 points/5 predicts a risk of developing clinically important pain at 4 months >30%, with an area under the curve-receiver operating characteristic of 0.81. DISCUSSION: We studied known risk factors for persistent pain in patients scheduled for breast cancer surgery and constructed a preoperative risk score simple enough to select high-risk patients in future prevention studies.

Prediction of Acute Postoperative Pain Following Breast Cancer Surgery Using the Pain Sensitivity Questionnaire: A Cohort Study.

OBJECTIVES: Previous studies have indicated that preoperative pain sensitivity correlates with postoperative pain intensity, and thus may be used to predict severe postoperative pain. Self-rating of pain sensitivity using the "Pain Sensitivity Questionnaire (PSQ)" may be an adjunct to these measures. METHODS: We tested the predictive ability of the PSQ as well as experimental parameters of pain sensitivity and other known risk factors for acute pain in 198 patients scheduled for breast cancer surgery. A multivariable logistic regression model was created for the binary outcome "maximum pain >3 during the first 24 hours postoperatively." RESULTS: The PSQ score proved to be an independent risk factor for at least moderate pain during the first 24 hours after surgery. Univariate analysis yielded in addition younger age, type of surgery (mastectomy vs. breast-conserving surgery), axillary dissection, expected pain, and the anxiety scores of the State-Trait Anxiety Inventory, as well as the score of the Beck Depression Inventory as risk factors. Of the experimental parameters of pain sensitivity, only the pain intensity elicited by a hot water bath was a predictor of at least moderate postoperative pain. Multivariable analysis led to a parsimonious model including only PSQ, the State-Trait Anxiety Inventory state score with a cutoff of ≥30, age with a cutoff of <55, mastectomy (vs. breast-conserving surgery), and axillary dissection. DISCUSSION: Results need to be validated in a larger cohort and for other types of surgery, but use of the simple PSQ may help to identify patients at risk of intense acute postoperative pain.