Effect of Acute Arterial Hypertension on Morphine's Requirements and Postsurgical Pain.

Pontificia Universidad Catolica de Chile

Status and phase: Completed; Phase 4

Conditions: Hypertensive Disease; Pain, Postoperative

Treatments: Other: SBP 20-30% over baseline; Other: SBP 20-30% under baseline

Study type: Interventional

Funder types: Other

Identifiers

NCT01897155

RIH_AP-UC-2012

Details and patient eligibility

About

The purpose of this randomized clinical trial is to evaluate the effect of acute arterial hypertension maintained during surgery on morphine's requirements in patients undergoing laparoscopic cholecystectomy

Full description

The high arterial blood pressure has been correlated with an increase in pain threshold in animal and humans. One of the explanations to this phenomenon is a baroreceptor activity and vasopressin release at the level of spinal cord dorsal horn and hypothalamus.

As far as we know, there is only one study about the effect of chronic hypertension on postoperative pain and none with acute hypertension. We therefore decided to conduct a randomized controlled trial to evaluate the effect of acute hypertension on postoperative morphine's requirements.

Enrollment: 50 patients

Sex: All

Ages: 20 to 60 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• American Society of Anesthesiology patient classification status(ASA) I-II
• Between 20 and 60 years of age
• Programed for elective laparoscopic cholecystectomy

Exclusion criteria

• History of arterial hypertension
• Baseline blood pressure over 139/89
• Use of opioids and any analgesic drug during the last 24 hours before surgery
• Chronic use of nonsteroidal antiinflammatory
• BMI > 34.9
• History of drug or alcohol abuse
• Use of medications that interfere in the central nervous system
• Adverse reactions to the drugs used in the study
• Pregnancy

Trial design

Primary purpose: Supportive Care

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

---

50 participants in 2 patient groups

SBP 20-30% under baseline

Other group

Description:

Induction of anesthesia was performed with remifentanil, pentothal 3 mg/kg and atracurium 0.5 mg/Kg. Anaesthesia was maintained with remifentanil (0.4 ug/Kg/min) and isoflurane adjusted to bispectral index (40-60). Patients received a phenylephrine infusion to maintain systolic blood pressure (SBP) 20% to 30% under baseline. The lower limit of SBP was 75 mmHg. In the recovery room, morphine was administered routinely at doses of 3 mg IV every 15 minutes until pain was less than 4 estimated by visual analog scale (VAS). VAS and pain threshold with von Frey filaments were assessed at 2, 6, 12 and 24 postoperative hours. All patients, received ketorolac 30 mg IV every 8 hours and intravenous morphine administered by patient controlled analgesia system (PCA) during the first 24 hours.

Treatment:

Other: SBP 20-30% over baseline

SBP 20-30% over baseline

Other group

Description:

Induction of anesthesia was performed with remifentanil, pentothal 3 mg/kg and atracurium 0.5 mg/Kg. Anaesthesia was maintained with remifentanil (0.4 ug/Kg/min) and isoflurane adjusted to bispectral index(40-60). Patients received a phenylephrine infusion in order to maintain systolic blood pressure (SBP) 20% to 30% over baseline. The upper limit of SBP was 165 mmHg. In the recovery room, morphine was administered routinely at doses of 3 mg IV every 15 minutes until pain was less than 4 estimated by visual analog scale (VAS). VAS and pain threshold with von Frey filaments were assessed at 2, 6, 12 and 24 postoperative hours. All patients, received ketorolac 30 mg IV every 8 hours and intravenous morphine administered by patient controlled analgesia system (PCA) during the first 24 hours.

Treatment:

Other: SBP 20-30% under baseline