Post-operative Emesis and Pain Outcomes After Cesarean Delivery

Overview

Approximately 20% women who undergo cesarean delivery would suffer from severe post-operative pain, which may further increase their risks from developing postpartum depression. Predictive factors such as pre-operative pain, age and anxiety could significantly contribute to post-operative nausea and vomiting (PONV) and pain in general surgery, however little information is available with regards to cesarean delivery. The investigators would investigate the risk factors of causing post-operative emesis after cesarean delivery, and to reaffirm that there is a positive correlation between pain on local anesthetic injection, presence of mechanical temporal summation (MTS) and post-Cesarean pain scores.

Full Title of Study: “Post-operative Emesis and Pain Outcomes After Cesarean Delivery (EPOC)”

Study Type

  • Study Type: Observational
  • Study Design
    • Time Perspective: Prospective
  • Study Primary Completion Date: December 31, 2020

Detailed Description

Approximately 1 in 5 women who undergo cesarean delivery would suffer from severe post-operative pain, which may further increase their risks from developing postpartum depression. Predictive factors such as pre-operative pain, age and anxiety could significantly contribute to post-operative nausea and vomiting (PONV) and pain in general surgery, however little information is available with regards to cesarean delivery. Previous studies demonstrated that pain scores upon local anesthetic injection is positively correlated to post-cesarean pain scores. Additionally, anxiety, anticipated post-operative pain score and anticipated medication need are also found to be promising risk factors to post-cesarean pain management.

The investigators would investigate the risk factors of causing post-operative emesis after cesarean delivery, and to reaffirm that there is a positive correlation between pain on local anesthetic injection, presence of mechanical temporal summation (MTS) and post-Cesarean pain scores. 200 parturients undergoing cesarean delivery and requiring regional anaesthesia will be recruited at KK Women's and Children's Hospital. Pain and anxiety assessment will be conducted via visual analogue scoring (VAS), MTS assessment and a series of questionnaires. After the delivery, all patients will be given appropriate analgesia, and the pain score at movement will be recorded. Secondary outcomes include pain scores at rest, analgesia consumption, time-to-first-rescue analgesia, opioid-related side effects, patient satisfaction and postpartum depression.

Interventions

  • Procedure: Mechanical Temporal Summation assessment
    • A 180 gram von Frey filament is applied on the subject’s forearm. Patient will then be asked to rate the pinprick pain score on a verbal rating scale, 0-100. Following this, 10 consecutive touches at random locations are applied with a 1 second interstimulus interval and within a 1 cm diameter circle. The patient will then be asked to rate the 10th pain score (0-100). The Mechanical Temporal Summation Score is obtained by the difference between the 11th pain score and the 1st pain score. If the score is greater than zero, the patient is implied to have presence of Mechanical Temporal Summation.
  • Other: Preoperative pain assessment
    • Patients will be asked to rate, using a 0-10mm visual analog scale (VAS), their surgical anxiety level (“On a scale of 0-100, with 0 being not anxious at all to 100 being extremely anxious, how anxious are you about your upcoming surgery?”), their anticipated pain (On a scale of 0-10, with 0 being no pain at all and 10 being pain as bad as you can imagine, how much pain do you anticipate experiencing after your upcoming surgery?”), and using a categorical scale, their anticipated pain medication need (“On a scale of 0 to 5, with 0 being none at all, 1 being much less than average, 2 being less than average, 3 being average, 4 being more than average, and 5 being much more than average, how much pain medication do you anticipate needing after your upcoming surgery?”).
  • Other: Questionnaires
    • Questionnaires including Hospital Anxiety and Depression Scale (HADS), EQ-5D-3L, Edinburgh Postnatal Depression Scale (EPDS), Pain Catastrophizing Scale (PCS), Central Sensitisation Inventory (CSI), pain survey and breastfeeding questionnaire will be administered to the patient.

Arms, Groups and Cohorts

  • Control
    • Questionnaires, Mechanical Temporal Summation assessment and preoperative pain assessment will be assigned to patient. Patients will be assigned to this group when they have a pain score of less than 3 (out of 10) at 6-10 post-delivery phone survey.
  • Postoperative pain
    • Questionnaires, Mechanical Temporal Summation assessment and preoperative pain assessment will be assigned to patient. Patients will be assigned to this group when they have a pain score of equal or more than 3 (out of 10) at 6-10 post-delivery phone survey.

Clinical Trial Outcome Measures

Primary Measures

  • Postsurgical pain scores in both groups: Numeric Rating Scale
    • Time Frame: 6 -10 weeks after delivery
    • Pain scores (Numeric Rating Scale 0-10) at 6-10 weeks follow-up evaluations. Zero being no pain, and 10 being the worst pain possible.

Secondary Measures

  • Pain vulnerability in both groups: Pain Catastrophizing Scale
    • Time Frame: 7 weeks (Upon recruitment until 5-14 days after delivery)
    • Assessment will be done via Pain Catastrophizing Scale (PCS) questionnaire before surgery. Pain catastrophizing refers to the negative thought processes patients have when they are exposed to pain or painful experiences. The PCS is a 13-item scale, with each item rated on a 5-point scale: 0 (Not at all) to 4 (all the time). It is broken into three subscales being magnification (0-12), rumination (0-16), and helplessness (0-24). A higher value in each subscale indicates a higher tendency to that subscale (worse outcome).
  • Mechanical Temporal Summation as measured by von Frey filament in both groups
    • Time Frame: 1 day (10 minutes)
    • Assessment will be done via Mechanical Temporal Summation assessment before surgery. A 180 gram von Frey filament is applied on the subject’s forearm. Patient will then be asked to rate the pinprick pain score on a verbal rating scale, 0-100. Following this, 10 consecutive touches at random locations are applied with a 1 second interstimulus interval and within a 1 cm diameter circle. The patient will then be asked to rate the 10th pain score (0-100). The Mechanical Temporal Summation Score is obtained by the difference between the 11th pain score and the 1st pain score. If the score is greater than zero, the patient is implied to have presence of Mechanical Temporal Summation.
  • Edinburgh Postnatal Depression Scale (EPDS) before and after delivery
    • Time Frame: 6 -10 weeks after delivery
    • Edinburgh Postnatal Depression Scale (EPDS) is a 10-item self reporting scale to evaluate the postnatal depression. Participants are asked to respond according to how they have felt in the past seven days. Each item is measured on a 4-point scale (0-3), with a total score in the range of 0 to 30. A higher total score indicates a greater degree of depressive symptoms. A score of 10 and above indicates clinically significant depressive symptoms.

Participating in This Clinical Trial

Inclusion Criteria

  • Pregnant and going to have caesarean delivery (36 weeks gestation or more; nulliparous and multiparous);
  • Healthy or have mild medical problems that are well-controlled (American Society of Anesthesiologists physical status 1-2).

Exclusion Criteria

  • History of intravenous drug or opioid abuse;
  • Previous history of chronic pain syndrome;
  • Emergency cesarean section;
  • Undergo general anaesthesia during cesarean delivery;
  • Non-English speaking.

Gender Eligibility: Female

Only female undergoing cesarean delivery in the institution will be recruited.

Minimum Age: 21 Years

Maximum Age: 50 Years

Investigator Details

  • Lead Sponsor
    • KK Women’s and Children’s Hospital
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Farida Ithnin, MB BCh BAO, Principal Investigator, KK Women’s and Children’s Hospital

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