Ventilation Strategy Reduces Postoperative Atelectasis

Sponsor

Region Västmanland (Other)

Overall Status

Withdrawn

CT.gov ID

NCT01911923

Collaborator

(none)

Enrollment

Location

Arms

Duration (Months)

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Atelectasis is common during and after general anesthesia. The investigators hypothesized that a ventilation strategy with a combination of 1) continuous positive airway pressure (CPAP) or positive end-expiratory pressure (PEEP) and 2) a reduced end-expiratory oxygen fraction (FETO2) before commencing mask ventilation with CPAP after extubation would reduce the area of postoperative atelectasis.

Condition or Disease	Intervention/Treatment	Phase
Pulmonary Atelectasis	Procedure: No CPAP/PEEP and 100 % oxygen Procedure: CPAP/PEEP and 30 % oxygen	N/A

Detailed Description

During general anesthesia, the combination of reduced functional residual capacity (FRC), high inspiratory oxygen fraction (FIO2), and airway closure are the main factors implicated in the atelectasis, shunt and shunt-like effects that account for the majority of the impaired oxygenation seen during general anesthesia.

Previous studies have shown that formation of atelectasis during preoxygenation and induction of anesthesia can be avoided by adding a continuous positive airway pressure (CPAP) followed by a positive end-expiratory pressure (PEEP).During emergence from anesthesia, high concentrations of oxygen predispose to atelectasis formation. Even a recruitment maneuver, followed by ventilation with 100% oxygen with a PEEP/CPAP of 10 cm H2O until extubation, failed to improve postoperative oxygenation compared with that achieved with zero end-expiratory pressure (ZEEP).This failure may have been caused by the presence of lung regions with high oxygen concentrations.

The investigators hypothesized that by inducing and discontinuing anesthesia during CPAP/PEEP and deliberately reducing FIO2 after extubation, postoperative atelectasis would be reduced compared with standard protocols. To test our hypothesis, the investigators studied 1) a control group with no CPAP/PEEP and a FIO2 of 1.0 while breathing spontaneously after extubation, and 2) an intervention group that was on CPAP/PEEP of 6 cmH2O from induction to extubation and that received an FIO2 of 1.0 until extubation and then an FIO2 of 0.3 via a facemask while on CPAP after extubation.

Study Design

Study Type:

Interventional

Actual Enrollment :

0 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Double (Participant, Outcomes Assessor)

Primary Purpose:

Treatment

Official Title:

Reduction in Postoperative Atelectasis by Continuous Positive Airway Pressure and Low Oxygen Concentration After Endotracheal Extubation.

Study Start Date :

Aug 1, 2013

Anticipated Primary Completion Date :

Nov 1, 2013

Anticipated Study Completion Date :

Nov 1, 2013

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: No CPAP/PEEP and 100 % oxygen This is the control group	Procedure: No CPAP/PEEP and 100 % oxygen This is the control group and 100 % oxygen will be used during induction of and emergence from anesthesia, no enhanced level of CPAP/PEEP is implemented. During controlled ventilation ventilation mode is volume controlled.
Experimental: CPAP/PEEP and 30 % oxygen This is the intervention group	Procedure: CPAP/PEEP and 30 % oxygen During all phases of anesthesia CPAP/PEEP will be used together with 100 % oxygen during induction of as well during emergence from anesthesia until after extubation when 30 % oxygen will be used.

Arm

Intervention/Treatment

Active Comparator: No CPAP/PEEP and 100 % oxygen

This is the control group

Procedure: No CPAP/PEEP and 100 % oxygen

This is the control group and 100 % oxygen will be used during induction of and emergence from anesthesia, no enhanced level of CPAP/PEEP is implemented. During controlled ventilation ventilation mode is volume controlled.

Experimental: CPAP/PEEP and 30 % oxygen

This is the intervention group

Procedure: CPAP/PEEP and 30 % oxygen

During all phases of anesthesia CPAP/PEEP will be used together with 100 % oxygen during induction of as well during emergence from anesthesia until after extubation when 30 % oxygen will be used.

Outcome Measures

Primary Outcome Measures

Area of atelectasis [30 minutes]
The area of atelectasis is investigated by computed tomography of the lungs postoperatively

Secondary Outcome Measures

Peripheral oxygen saturation (SpO2) [2 hours]
SpO2 is assessed immediately after extubation and then continuously postoperatively

Eligibility Criteria

Criteria

Ages Eligible for Study:

20 Years to 75 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Adult patients up to 75 years of age.
American Society of Anesthesiologists (ASA) physical status class I-III.
Be able to climb two flight of stairs without stopping.
SpO2 of ≥ 94% when breathing air in the supine position.
A body mass index (BMI, weight in kilograms divided by the square of the height in meters) of < 31.

Exclusion Criteria:

Patients with chronic obstructive pulmonary disease.
Smokers.
Ex smokers if smoked more than 5 pack years.
Overt heart failure
Known or predicted difficult intubation.

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Västmanlands sjukhus Köping	Köping	Västmanland	Sweden	721 89

Sponsors and Collaborators

Region Västmanland

Investigators

Principal Investigator: Lennart Edmark, Md, Landstinget Vastmaland

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

Responsible Party:

Lennart Edmark, M.D., Region Västmanland

ClinicalTrials.gov Identifier:

NCT01911923

Other Study ID Numbers:

Dnr 2008 / 251

First Posted:

Jul 30, 2013

Last Update Posted:

Aug 26, 2014

Last Verified:

Aug 1, 2014

Additional relevant MeSH terms:

Pulmonary Atelectasis

Study Results

No Results Posted as of Aug 26, 2014