High Fresh Gas Flow After Intubation

High Fresh Gas Flow After Intubation - A Randomized Clinical Trial

Atelectasis is common during and after general anesthesia. Atelectasis develops early if preoxygenation with 100% oxygen is used and continuously used during induction until endotracheal intubation. The investigators hypothesize that a rapid anti-preoxygenation maneuver immediately after confirming a successful intubation, reduces the area of atelectasis as investigated by computed tomography compared to a standard procedure.

Study Overview

• Status: Completed
• Conditions: Atelectasis
• Intervention / Treatment: Procedure: Control group, conventional ventilatory settings; Procedure: High fresh gas flow, high minute ventilation

• Study Type: Interventional
• Enrollment (Actual): 24
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Sweden
  • Västmanland
    • Köping, Västmanland, Sweden, 731 30
      • Landstinget Västmanland

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Healthy patients, American Society of Anesthesiology (ASA) I-II
• Patients scheduled for orthopaedic day case surgery in general anaesthesia

Exclusion Criteria:

• ASA class III or higher
• Body Mass Index (BMI) 30 or higher
• Arterial oxygen saturation (SpO2) <94% breathing air
• Chronic Obstructive Pulmonary Disease (COPD)
• Ischemic heart disease
• Haemoglobin <100g/L
• Known or anticipated difficult airway and/or intubation
• Active smokers and ex-smokers with a history of more than 6 pack years
• Need for interscalene or supraclavicular regional anaesthesia with risk of phrenic nerve paralysis

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Control group, conventional ventilatory settings; Handling of the airway during induction and intubation is performed in a conventional manner. Initial ventilatory settings are also done in a conventional manner.	Procedure: Control group, conventional ventilatory settings; Handling of the airway during induction and intubation is performed in a conventional manner. Initial ventilatory settings are also done in a conventional manner. As soon as correct position of the endotracheal tube is confirmed, controlled ventilation is started with a tidal volume of 7 mL/kg ideal body weight, PEEP 6 or 8 cm H2O (8 if BMI >25) and a respiratory frequency of 10. The fresh gas flow is set to 1 Liter per minute with an oxygen mixture of 40%, aiming for an inspired FiO2 of 30-35%. Unless the patient´s SpO2 falls below 90%, the FiO2 remains unchanged throughout the procedure.
Active Comparator: High fresh gas flow, high minute ventilation; Handling of the airway during induction and intubation is performed in a conventional manner. Immediately after confirming a successful intubation the effect of preoxygenation is eliminated with an anti-preoxygenation maneuver.	Procedure: High fresh gas flow, high minute ventilation; Handling of the airway during induction and intubation is performed in a conventional manner. Immediately after confirming a successful intubation, the effect of preoxygenation is eliminated with a fresh gas flow of 10 L/min of air, delivered with volume controlled ventilation consisting of tidal volumes of approximately 15 ml/kg ideal body weight, a positive expiratory pressure of 10 cm H20 and a respiratory frequency of 10. As soon as the end tidal O2 reaches 25%, the ventilator settings are adjusted to normal values (same as in the control group), i.e. tidal volume 7 mL/kg ideal body weight, PEEP 6 or 8 cm H2O (8 if BMI >25). The mixture of oxygen in the fresh gas is increased to 40% and the fresh gas flow is set to 1 Liter per minute, aiming for an inspired FiO2 of 30-35%. Unless the patient´s SpO2 falls below 90%, the FiO2 remains unchanged throughout the procedure.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Atelectasis	The area of atelectasis in the lungs is assessed by computed tomography (CT) 10 mm above the dome of the right diaphragm and expressed in cm2 and as % of the total lung area in the particular scan.	Within 1-2 hours, just before emergence from anesthesia

Secondary Outcome Measures

Outcome Measure	Time Frame
Arterial blood gases	Within 2-3 hours perioperatively

Collaborators and Investigators

• Sponsor: Region Västmanland
• Investigators: Study Chair: Mats Enlund, MD, PhD, Landstinget i Värmland

Study record dates

Study Major Dates

• Study Start: September 1, 2014
• Primary Completion (Actual): May 1, 2015
• Study Completion (Actual): May 1, 2015

Study Registration Dates

• First Submitted: August 1, 2014
• First Submitted That Met QC Criteria: August 12, 2014
• First Posted (Estimate): August 13, 2014

Study Record Updates

• Last Update Posted (Estimate): May 13, 2015
• Last Update Submitted That Met QC Criteria: May 12, 2015
• Last Verified: May 1, 2015

More Information

Terms related to this study

• Keywords: Prevention; Anaesthesia; Atelectasis; Oxygenation; Fresh gas flow
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Pulmonary Atelectasis
• Other Study ID Numbers: Dnr 2012/335