Isocapnic Hyperventilation - an Alternative Method

December 29, 2017 updated by: Katarina Hallén, Sahlgrenska University Hospital, Sweden

Isocapnic Hyperventilation for Enhancing Recovery After Inhalation Anaesthesia - an Alternative Method

Isocapnic hyperventilation (IHV) is a method that shortens time to extubation after inhalation anaesthesia by increasing airway carbon dioxide (CO2) during hyperventilation (HV). In two experimental studies (mechanical lung model and porcine model) and in a pilot study on patients undergoing sevoflurane anaesthesia for major ear-nose-throat (ENT) surgery, the investigators evaluated the feasibility of an alternative technique of IHV. By performing a prospective, randomised controlled study, the investigators want to further test this alternative method for IHV.

Study Overview

Status

Completed

Intervention / Treatment

Detailed Description

Isocapnic hyperventilation (IHV) provides an alternative method for weaning from inhalation anaesthesia which decreases the time to eye-opening, extubation and time spent in the PACU. The method is well known since at least 40-50 years and involves the maintenance of a stable CO2 level during hyperventilation, which increases the elimination of anaesthetic gas without producing hypocapnia. Studies have declared that the reduction in time to eye-opening is 50-60 % compared to a standard weaning procedure after inhalation anaesthesia.

There are several principally different ways to maintain the CO2 level during hyperventilation, where a number of technical solutions that add dead-space to the anaesthesia circuit and thereby produce rebreathing of CO2 during hyperventilation are the most studied methods so far. However, the original method of directly adding CO2 to the breathing circuit during hyperventilation could be considered in need of a re-evaluation, as modern anaesthesia delivery units and monitoring equipment to a great extent can eliminate the risk of hypercapnia, that was described with this procedure in the 1980ies.

An alternative IHV method is to directly infuse CO2 to the inspiratory limb of the breathing circuit through a mixing box while using mechanical hyperventilation by a standardised protocol. This technique was recently evaluated by the investigators, in a bench test, and in an in vivo model. Based on these studies, the CO2 dosage needed to achieve isocapnia during HV at various levels of alveolar ventilation, CO2 production and dead space was estimated and a gender- and weight-based nomogram for CO2 delivery during IHV was constructed. Furthermore, the investigators could show, in vivo, that the washout time of sevoflurane anaesthesia was one-third compared to normal ventilation. The feasibility of this IHV method was evaluated in a pilot study in humans, based on the results of our two previous experimental studies. To finalize the project the investigators now conduct a prospective randomized trial to evaluate the efficacy of the method, compared to a standard weaning procedure, after long-term sevoflurane anaesthesia.

Study Type

Interventional

Enrollment (Actual)

31

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • Gothenburg, Sweden, 41345
        • Sahlgrenska University Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Adult patients scheduled for major elective ear-nose-throat (ENT) surgery after informed consent was obtained during the pre-operative evaluation.

Exclusion Criteria:

  • Patients with severe pulmonary or circulatory disease

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Isocapnic hyperventilation
After end of surgery, hyperventilation and administration of a small, precalculated amount of CO2 into the breathing circuit will be performed.
Mechanical hyperventilation to enhance elimination of inahalation anesthetics. Administration of a precalculated flow of CO2 according to gender and weight into the inspiratory limb of the breathing circuit in order to avoid hypocapnia.
Other Names:
  • Normocapnic hyperventilation
No Intervention: Standard procedure
After end of surgery, patients will be subdued to a standard weaning procedure.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Time to extubation
Time Frame: 5-20 minutes
5-20 minutes
Time to eye-opening
Time Frame: 10-25 minutes
10-25 minutes
Time to discharge from OR
Time Frame: 15-40 minutes
15-40 minutes

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Postoperative recovery
Time Frame: 60 minutes
Postoperative quality of recovery (PQRS) scale
60 minutes
Time to eligible for discharge from post-anaesthesia care unit (PACU)
Time Frame: 1-6 hours
1-6 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 11, 2016

Primary Completion (Actual)

August 15, 2017

Study Completion (Actual)

August 15, 2017

Study Registration Dates

First Submitted

March 3, 2017

First Submitted That Met QC Criteria

March 3, 2017

First Posted (Actual)

March 8, 2017

Study Record Updates

Last Update Posted (Actual)

January 2, 2018

Last Update Submitted That Met QC Criteria

December 29, 2017

Last Verified

December 1, 2017

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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