Impact of Interscalene Nerve Block on Cerebral Perfusion During Surgery in the Beachchair Position

This study is currently recruiting participants. (see Contacts and Locations)
Verified June 2014 by Centre hospitalier de l'Université de Montréal (CHUM)
Sponsor:
Information provided by (Responsible Party):
Centre hospitalier de l'Université de Montréal (CHUM)
ClinicalTrials.gov Identifier:
NCT01983618
First received: November 7, 2013
Last updated: June 5, 2014
Last verified: June 2014
  Purpose

Beachchair position is used by many orthopaedic surgeons for shoulder surgery. Most patients undergoing surgery in this position have no complications. However, reported cases of postoperative neurological deficits have highlighted the risk of cerebral and spinal cord ischemia. The etiology of such complications remains unclear. The most plausible explanation for these events would be intraoperative hypotension followed by cerebral hypoperfusion.

General anesthesia is commonly used for shoulder surgery in conjunction with interscalene brachial plexus blockade. During the block, local anesthetic's spread is frequently observed leading to a block of sympathetic fibres. Since all nerves located in the head and neck area go through the stellate ganglion, its block will cause a sympathetic denervation and a decrease of the peripheral vascular resistance, thus increasing the circulation in cerebral blood vessels. In normal situations, there is a vasoconstriction of the cerebral blood vessels in response to a sympathetic stimulation and a vasodilation if sympathetic fibres are blocked.

Transcranial Doppler (TCD) is a non-invasive examination that provides a reliable evaluation of intracranial blood flow in real-time. It can help to detect sudden changes in perfusion and identify potential embolic events. Some studies using TCD have shown an increased ipsilateral cerebral blood flow (CBF) secondary to a reduced vascular tone associated with a stellate ganglion block. Others have shown a reduction of contralateral CBF that could theoretically increase the risk of ischemia in the affected area.

This study will assess the role of interscalene nerve blockade in the protection of cerebral ischemia and preservation of cerebral autoregulation. This study will also aim to identify changes in contralateral CBF.

The investigators hypothesize that:

  1. Interscalene nerve block will increase CBF
  2. Interscalene nerve block will not decrease contralateral CBF
  3. Cerebral autoregulation will be preserved under general anesthesia in conjunction with an interscalene nerve block in this setting.

Condition Intervention
Cerebral Ischemia
Procedure: Interscalene nerve block and catheter
Procedure: Interscalene catheter

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Single Blind (Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Impact of Interscalene Nerve Block on Cerebral Perfusion During Surgery in the Beachchair Position Under General Anesthesia

Further study details as provided by Centre hospitalier de l'Université de Montréal (CHUM):

Primary Outcome Measures:
  • Cerebral blood flow in the median cerebral artery [ Time Frame: From arrival in the operating theatre until the end of surgery. Patients will be followed for an average of 3 hours. ] [ Designated as safety issue: Yes ]
    Cerebral blood flow will be assessed using the transcranial Doppler. Because the bones of the skull block the transmission of ultrasound, region with thinner walls must be used for analyzing. For this reason, recording will be performed in the temporal region above the zygomatic arch.


Secondary Outcome Measures:
  • Arterial blood pressure [ Time Frame: From arrival in the operating theatre until the end of surgery. Patients will be followed for an average of 3 hours. ] [ Designated as safety issue: Yes ]
    Arterial blood pressure will be measured during each TCD.

  • Body temperature [ Time Frame: From induction of anesthesia until the end of surgery. Patients will be followed for an average of 2 hours. ] [ Designated as safety issue: Yes ]
    Body temperature will be recorded at every TCD performed following induction of general anesthesia.

  • End-tidal carbon dioxide [ Time Frame: From induction of anesthesia until the end of surgery. Patients will be followed for an average of 2 hours. ] [ Designated as safety issue: Yes ]
    End-tidal carbon dioxide will be recorded at every TCD performed following induction of general anesthesia.

  • Minimum alveolar concentration (MAC) of Desflurane [ Time Frame: From induction of anesthesia until the end of surgery. Patients will be followed for an average of 2 hours. ] [ Designated as safety issue: Yes ]
    Minimum alveolar concentration of Desflurane will be recorded at every TCD performed following induction of general anesthesia.


Estimated Enrollment: 25
Study Start Date: February 2014
Estimated Study Completion Date: December 2014
Estimated Primary Completion Date: December 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: Interscalene catheter
No block will be performed prior to surgery. An interscalene catheter will be inserted under ultrasound guidance by the anesthesiologist before the induction of anesthesia. Local anesthetics will only be administered once all TCD assessments are completed but prior to the end of surgery.
Procedure: Interscalene catheter
Experimental: Interscalene nerve block and catheter
The anesthesiologist will perform the interscalene nerve block and insert an interscalene catheter under ultrasound guidance before induction of anesthesia. A standardized mixture of bupivacaine, lidocaine and epinephrine will be administered prior to surgery.
Procedure: Interscalene nerve block and catheter

Detailed Description:

Prior to surgery, each patient will undergo a baseline bilateral TCD examination in supine position. If the Doppler's results are satisfactory, the patient will then be randomized and proceed to the next step. In case of inadequate results, the patient's participation to the study will be terminated.

The interscalene nerve block and the insertion of the interscalene catheter will be performed according to randomization. In the interscalene nerve block and catheter group, the attending anaesthesiologist will assess the success of the block and record the presence or absence of Horner's syndrome. The transcranial Doppler operator will be blinded to these observations. Following the insertion of the interscalene catheter, the patient will undergo a second bilateral TCD in supine position before induction of anesthesia.

The anesthetic technique and monitoring will be standardized. After the induction of anesthesia, a bilateral TCD will be performed with the patient in supine position. Another examination will be performed under general anesthesia immediately after and 30 minutes following the installation of the patient in the beachchair position. A last TCD will be performed after a reduction of end-tidal carbon dioxide at 30 mm Hg.

For each examination, the arterial blood pressure must be stabilized for at least 5 minutes before the Doppler can be initiated. Arterial blood pressure will be measured during each examination. Type, duration of surgery and beachchair position will be recorded. Vasopressor therapy will be noted. Body temperature, end-tidal carbon dioxide and minimum alveolar concentration of desflurane will be collected during each examination performed under general anesthesia.

  Eligibility

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Scheduled for shoulder surgery in the sitting position
  • Surgery of the shoulder and clavicular area, eligible to an interscalene nerve block
  • American Society of Anesthesiologists (ASA) physical status 1-3

Exclusion Criteria:

  • Carotid artery stenosis
  • History of stroke or other significant central nervous system lesion
  • Inadequate temporal window to perform transcranial Doppler
  • Contraindication to interscalene nerve block
  • Patient refusal
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01983618

Contacts
Contact: Sébastien Garneau, MD, FRCPC 514-890-8000 ext 26876 sebastien.garneau@umontreal.ca
Contact: François Girard, MD, FRCPC 514-890-8000 ext 26876 francois.girard.chum@ssss.gouv.qc.ca

Locations
Canada, Quebec
Centre Hospitalier de l'Université de Montréal (CHUM) Recruiting
Montreal, Quebec, Canada, H2L 4M1
Contact: Sébastien Garneau, MD, FRCPC    514-890-8000 ext 26876    sebastien.garneau@umontreal.ca   
Contact: Monique Ruel, RN, CCRP    514-890-8000 ext 24542    monique.m.ruel.chum@ssss.gouv.qc.ca   
Sub-Investigator: François Girard, MD, FRCPC         
Sub-Investigator: Luis Herrera, MD         
Sub-Investigator: Céline Odier, MD, FRCPC         
Sponsors and Collaborators
Centre hospitalier de l'Université de Montréal (CHUM)
Investigators
Principal Investigator: Sébastien Garneau, MD, FRCPC Centre hospitalier de l'Université de Montréal (CHUM)
  More Information

No publications provided

Responsible Party: Centre hospitalier de l'Université de Montréal (CHUM)
ClinicalTrials.gov Identifier: NCT01983618     History of Changes
Other Study ID Numbers: 13.226
Study First Received: November 7, 2013
Last Updated: June 5, 2014
Health Authority: Canada: Ethics Review Committee

Keywords provided by Centre hospitalier de l'Université de Montréal (CHUM):
Cerebral ischemia
Beachchair position
Interscalene nerve block

Additional relevant MeSH terms:
Cerebral Infarction
Brain Infarction
Brain Ischemia
Ischemia
Cerebrovascular Disorders
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Stroke
Vascular Diseases
Cardiovascular Diseases
Pathologic Processes

ClinicalTrials.gov processed this record on July 24, 2014