<!-- Not Allowed Tag Filtered --><Backgrounds and hypothesis>
- Prescription opioids are routinely used to decrease postoperative pain after cesarean section. There are problems of misuse or overuse of opioid medications of postpartum women with cesarean section. There is no standard recommendation for pain management after the cesarean section. Prescription opioids are secreted into breast milk made from the blood of mothers who consume these medications, and their neonates exposed to these drugs can have a risk of adverse effects including infant sleepiness, neonatal apnea, irritability, and poor neonate adaptation syndrome. These effects are more pronounced, especially in premature and neonates with growth failure. 
- Recently the combined effect of local anesthetics and opiates has gained wide popularity because it reduces the amounts of opiates. On-Q Pain Management System (On-Q) is a kind of local analgesic device that delivers continuous local analgesia to the abdominal surgical wound. The effectiveness of On-Q for pain control in patients undergoing various kinds of surgeries was found. If the On-Q is used in the patient with the cesarean section, the benefit of local analgesics is added avoiding the exposure of opiates to neonate through breast milk. 
- As the hypothesis, the ON-Q can control the postoperative pain efficiently, and decrease the amount of opioid drugs for pain control.  

<!-- Not Allowed Tag Filtered --><Aims>
1. primary objective: the degree of controlling postoperative pain after the cesarean section 
2. secondary objective: adverse events, the requirement of additional pan killer, the amount of opiates. 

< Methods> 
1. Randomized study selection: Pregnant women who agreed to participate in this study were randomly assigned to the test group and the control group at a 1: 1 ratio after being assigned a registration number. Local anesthetics were injected into the test group through ON-Q, and saline was injected into the control group. A sealed envelope was produced using a randomized table created by the Excel program. The clinical trial begins by opening the envelope in the order of the number written on the outside of envelope. After being divided into a test group or a control group, the drug or saline is injected as determined in the envelope, and proceeded by blinding the clinical subjects.
2. In the test group, 200 cc of 0.75 % ropivacaine was injected into the On-Q pump, and 200 cc of saline was injected into the control group.
3. Local area pain control device (On-Q®) is provided by B-Brown Korea Co., Ltd. and is discarded when removed 2 days after surgery.
4. Installation of device: During the cesarean section, after the peritoneum layer is closed, a guide needle is inserted into the per-cutaneous puncture at a position 3-5 cm away from the surgical site. The medication or saline is continuously infused at 2-5 cc per hour into the wound and removed postoperative 2 days.
5. All subjects receive the patient-controlled analgesia (PCA) filled with fentanyl 1,000 mcg and antiemetics.
6. Assessment: Pain control degree, PCA usage, additional analgesic, and drug side effects were investigated 3 times (within 8 hours after surgery, 1 day after surgery, and 2 days after surgery).
7. Sample collection: An additional 2 cc of blood is sampled during the completed blood count test the next day after surgery and stored in a -70 degree freezer.
8. Measurement of fentanyl concentration in maternal blood: After the recruitment of study subjects is completed, stored blood samples are sent to a laboratory and the serum fentanyl concentration is measured using liquid-based tandem mass spectrometry (Korea Polymer testing and Research Institute, Department of Medical Engineering Kyunhee University).

Treatment

In the test group, 200 cc of ropivacaine 0.75% concentration was injected into the On-Q pump, and 200 cc of physiological saline was injected into the control group.

Arm Label

Target Number of Participant

Arm Type

Arm Description

In the test group, 200 cc of ropivacaine 0.75% concentration was injected into the On-Q pump.

Arm Label

Target Number of Participant

Arm Type

Arm Description

200 cc of physiological saline was injected into the On-Q pump in the control group.

Gender

Age

Description

1) women planning to get the cesarean section delivery
2) women who can read and understand the Korean.  
3) women without the exclusion criteria 
4) women giving informed consent

Exclusion criteria : 
1) A person who has allergic reaction to the bupivacaine
2) Drug addicts or alcoholics
3) A person with a history of mental illness 
4) Serum Creatinine > 2mg/dL

pain scaling score

within 8 hours after c/sec, the next day after operative day, post c/sec  2 day

fentanyl concentration

post operative day (POD1 day)

Sixty-nine patients (35 in the study and 34 in the control group) were analyzed. The mean
VAS scores were lower in the study group all three periods, with significance achieved at day 2 (2.74 ±
0.0.95 versus 3.41 ± 1.33, p=0.0287). The intravenous fentanyl consumptions were significantly lower
in the study group at all three periods. Total administration of additional non-opioid analgesics
including ketorolac, propacetamol, and pethidine was higher in the control group.