Recruiting

Renin-Angiotensin System Blockade

Sponsor:

London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's

Code:

NCT01715584

Conditions

Hypertension

Eligibility Criteria

Sex: All

Age: 40+

Healthy Volunteers: Not accepted

Interventions

Sevoflurane/oxygen/air/nitrous oxide

Study Details

Brief summary:

It is controversial whether or not patients whose Renin Angiotensin System is blocked for the treatment of hypertension suffer increased risk when undergoing surgery and anaesthesia.

The investigators wish to test the hypothesis: Blockade of the Renin Angiotensin System causes altered dose response under general anaesthesia in a dose dependant manner. The investigators wish to look for altered responses across the usual anaesthetic dosing range as measured by blood pressure and heart responses.

Conditions

Hypertension

Study ID

NCT01715584

Start date

Jul, 2012

Status verified date

Aug, 2017

Completion date

Dec 31, 2019

Anticipated

Primary completion date

Dec 31, 2019

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 40+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • age over 40
  • composite head and neck tumor resection
  • treated hypertension
  • hypertension medications taken on morning of surgery (except diuretics)

Exclusion Criteria:

  • patient refusal
  • age less than 40 or over 80 years
  • combined surgical procedures
  • emergency surgery
  • Left ventricular ejection fraction less than 50 per cent
  • calculated creatinine clearance less than 60 mL per minute

Study Design

Enrollment

80 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

other: Angiotensin Converting Enzyme Exposed

Sevoflurane/oxygen/air/nitrous oxide

Hypertensive patients exposed to Angiotensin Converting Enzyme Inhibitors (ACE Inhibitors)will make up this arm.

Preoperative Exposure to any of the following Angiotensin Converting Enzyme Inhibitors Enalapril (Vasotec/Renitec) Ramipril (Altace/Prilace/Ramace/Ramiwin/Triatec/Tritace) Quinapril (Accupril) Perindopril (Coversyl/Aceon) Lisinopril (Listril/Lopril/Novatec/Prinivil/Zestril) Benazepril (Lotensin) Imidapril (Tanatril) Zofenopril (Zofecard) Trandolapril (Mavik/Odrik/Gopten) Fosinopril (Fositen/Monopril)

other: Angiotensin Receptor Blocker Exposed

Sevoflurane/oxygen/air/nitrous oxide

Hypertensive patients exposed to Angiotensin Receptor Blocking Agents (ARBs).

Preoperative Exposure to any of the following Angiotensin II Receptor Blocking Agents Losartan(Cozaar) Candesartan (Atacand) Valsartan (Diovan) Irbesartan (Avapro) Telmisartan (Micardis) Eprosartan (Teveten) Olemisartan (Benicar) Azilsartan (Edarbi)

other: Non ACE/ARB Exposed

Sevoflurane/oxygen/air/nitrous oxide

Hypertensive patients not exposed to angiotensin converting enzyme inhibitors or Angiotensin receptor blocking agents will be put into this arm.

Interventions

Sevoflurane/oxygen/air/nitrous oxide

Patients in each arm will be randomized to receive either: 50 per cent oxygen, air, and sevoflurane or 50% nitrous oxide, oxygen and sevoflurane. They will then cross over to the other gas mixture. The depth of each the anesthetic will be varied from 0.8 MAC (minimum alveolar concentration) to 1.6 MAC in 0.2 MAC steps. Hemodyamic variables will be measured at each anesthetic concentration (average of five measurements). Time will be allowed for anesthetic agent equilibration. Paralysis and analgesia using rocuronium and fentanyl will be provided to ensure patients do not move at low (less than 1.0 MAC. It is estimated the time for the cross over experiment will be approximately six hours.

Primary outcome measure

  • Systemic Vascular Resistance Index (SVRI) [ Time Frame: approximately every 5 minutes for 6 hours ]

Central Contacts and Locations

Central contacts

Craig J Railton, MD PhD FRCPC

519 685 8500Craig.Railton@lhsc.on.ca

Locations

London Health Sciences Centre - Victoria Campus

Recruiting

London, Ontario, Canada, N6A 5W9

Contacts

Craig J Railton, MD, PhD

519 685 8500Craig.Railton@lhsc.on.ca

Principal Investigator:

Craig J Railton, MD, PhD

More Information

Sponsor

London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's

Last update posted

Aug 23, 2017

Last verified

Aug, 2017

Keywords

  • Hypertension
  • Sevoflurane
  • Inhaled Anesthetic
  • Angiotensin Converting Enzyme Inhibitor
  • Angiotensin II Receptor Blocking Agent

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's on 2017-08-23.