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

Study Overview
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Brief Summary
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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

Detailed Description
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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.

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

Conditions
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Pain, Postoperative, Hypertensive Disease

Intervention / Treatment
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* Other: SBP 20-30% over baseline
* Other: SBP 20-30% under baseline


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: SBP 20-30% under baseline<br>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. | Other: SBP 20-30% over baseline<br>* Patients were assigned to receive a phenylephrine infusion in order to maintain systolic blood pressure (SBP) 20% to 30% over the baseline. The upper limit of systolic blood pressure is 165 mmHg.<br>|
| Other: SBP 20-30% over baseline<br>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. | Other: SBP 20-30% under baseline<br>* Patients were assigned to receive a phenylephrine infusion in order to maintain systolic blood pressure (SBP) 20% to 30% below the baseline. The lower limit of systolic blood pressure is 75 mmHg<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Morphine requirement post laparoscopic cholecystectomy | Measure of morphine consumption during the first 24 postoperative hours in patients undergoing laparoscopic cholecystectomy. | First 24 hours postoperative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effects of acute hypertension in pain scores |  | First 24 hours postoperative | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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analgesia, postoperative;, analgesics opioid;, hyperalgesia;, remifentanil;, hypertension.