Clinical trial NCT03494842: TENS for Suction Evacuation for Termination of 1st Trimester Pregnancies
Official title: A Doubled Blinded Randomised Controlled Trial of Conscious Sedation With Transcutaneous Nerve Stimulation for Pain Relief During Suction Evacuation for Termination of First Trimester Pregnancies
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Pregnancy, Abdominal
Termination of Pregnancy
Pain, Nerve
Keywords: TENS
pain relief
STOP
surgical abortion
Lead sponsor: Queen Mary Hospital, Hong Kong
Sponsor class: OTHER
First posted: 2018-04-11
Enrollment: 170
Sex: FEMALE
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: To study the effectiveness of the pain relief method of transcutaneous electrical nerve stimulation (TENS) for women who will undergo suction evacuation under conscious sedation for first trimester termination of pregnancy.

Detailed description: Suction evacuation is a minor gynecological procedure commonly performed at an outpatient setting for termination of pregnancy. Although it is a simple surgical procedure lasting 5-10 min and can be done under various methods of pain control, 78-97% of women still report at least moderate procedural pain, especially during injection of paracervical block, cervical dilation, suction aspiration and postoperatively with uterine cramping. In addition, those pharmacological analgesic methods are often associated with numerous adverse effects and cannot be applicable to all women.

The transcutaneous nerve stimulation (TENS) method is commonly used to treat labour pain. It is an inexpensive, quick, easy to use and noninvasive pain relief method. A recent study by Lison et al. on TENS for office hysteroscopy demonstrated a significant decrease in pain scores when compared to control and placebo groups.

The rationale of TENS lies in achieving pain reduction when electric stimulation alters the nociceptive transmission in the dorsal horn of the spinal cord; this means the electrode has to be adequately applied in the right receptive field of the body to achieve pain control. For the setting of TENS there is evidence supporting superior pain relief by random high frequencies TENS over fixed frequency. Increasing the pulse duration to above 250 microseconds also produces better analgesics effect.

In suction evacuation, the nerve roots of T10-L1 and S2-S4 becomes relevant as they correspond to the nerve supply to the whole uterus and cervix. Lison et al placed electrodes at these levels parallel to the spinal cord in their study and have instructed their subjects to increase the TENS intensity to the maximum nonpainful level, allowing further increase when their stimulus perception decrease as a result of nerve accommodation.

Its use in suction evacuation however, remains undetermined as there is no published study in this area.

Eligibility criteria: Inclusion Criteria:

* Chinese aged 18 years or above and mentally competent
* Up to 12 weeks gestation on the day of STOP
* Size of the uterus on pelvic examination compatible with estimated duration of pregnancy, or dating confirmed with ultrasound scan
* Normal general and gynecological examination

Exclusion Criteria:

* Skin damage or allergy at site of TENS pads application
* Previous experience with TENS
* History of pacemarker insertion
* History of severe respiratory or cardiac disease
* Severe and recurrent liver disease
* Allergic to lignocaine
* Myasthenia gravis
* Psychiatric conditions requiring medication
* Disorders that constitute contraindications to use of prostaglandins

Primary outcomes:
measure: To assess the change of 100-point visual analogue pain scale in 3 time points
timeFrame: Patient will be asked for the pain intensity by using the 100 mm linear VAS 5 minutes before receiving the active TENS/ placebo TENS before the start of suction evacuation, reassess 20 minutes later and 1 hour after operation.
Secondary outcomes:
measure: To assess the change of Anxiety level of the patients in 3 time points by using State-Trait Anxiety Inventory Questionnaire to record patient's anxiety level.
timeFrame: Patient will be asked for the anxiety level by using STAI 5 minutes before receiving the active TENS/ placebo TENS before the start of suction evacuation, reassess 20 minutes later and 1 hour after operation.
measure: To assess the difficulty of the operation
timeFrame: The surgeon will be asked to fill the assessment form right after the suction evacuation operation immediately.
Other outcomes:
Locations:
city: Hong Kong
country: Hong Kong
facility: Queen Mary Hospital
Study officials:
affiliation: Queen Mary Hospital, Hong Kong
name: Keedon Wong, MBBS
role: PRINCIPAL_INVESTIGATOR
References:
citation: Belanger E, Melzack R, Lauzon P. Pain of first-trimester abortion: a study of psychosocial and medical predictors. Pain. 1989 Mar;36(3):339-350. doi: 10.1016/0304-3959(89)90094-8.
citation: Wong CY, Ng EH, Ngai SW, Ho PC. A randomized, double blind, placebo-controlled study to investigate the use of conscious sedation in conjunction with paracervical block for reducing pain in termination of first trimester pregnancy by suction evacuation. Hum Reprod. 2002 May;17(5):1222-5. doi: 10.1093/humrep/17.5.1222.
citation: Lison JF, Amer-Cuenca JJ, Piquer-Marti S, Benavent-Caballer V, Bivia-Roig G, Marin-Buck A. Transcutaneous Nerve Stimulation for Pain Relief During Office Hysteroscopy: A Randomized Controlled Trial. Obstet Gynecol. 2017 Feb;129(2):363-370. doi: 10.1097/AOG.0000000000001842.
citation: Vance CG, Dailey DL, Rakel BA, Sluka KA. Using TENS for pain control: the state of the evidence. Pain Manag. 2014 May;4(3):197-209. doi: 10.2217/pmt.14.13.
citation: Sluka KA, Walsh D. Transcutaneous electrical nerve stimulation: basic science mechanisms and clinical effectiveness. J Pain. 2003 Apr;4(3):109-21. doi: 10.1054/jpai.2003.434.