Preoxygenation With Positive Inspiratory Pressure During Induction of Anesthesia (PREOX)

Randomized Controlled Trial on Preoxygenation Through Spontaneous Breathing or Non Invasive Positive Pressure Ventilation With and Without Positive End Expiratory Pressure

Adults patients scheduled for elective surgery were randomly allocated to receive preoxygenation with spontaneous breathing, positive pressure ventilation (positive inspiratory pressure: 12 cmH2O) without PEEP, and with PEEP (positive inspiratory pressure: 12 cmH2O, PEEP: 6 cmH2O). Preoxygenation time was measured from face mask positioning to FEO2=90% (FEO2 : expired fraction of O2). After endotracheal tube placement the time until SpO2=93% (SpO2 : peripheral oxygen saturation) was measured during monitored apnoea. Patient's discomfort was recorded (visual analogue scale).

Study Overview

• Status: Completed
• Conditions: Anesthesia
• Intervention / Treatment: Other: PPV : positive pressure ventilation; Other: PEEP : PPV + PEEP

Detailed Description

Inclusion criteria : age older 18 years, American Society of Anesthesiologists physical status I and II, and scheduled surgery with general anaesthesia and oro-tracheal intubation.

Exclusion criteria : rapid sequence induction, anticipated difficult mask ventilation (2 or more factors among age > 55 years, body mass index > 26 kg m-2, beard, history of snoring, lack of teeth), anticipated difficult intubation (history of difficult intubation, Mallampati class 3 and 4, thyromental distance < 60 mm, interincisor distance < 35 mm, limited cervical spine movement), and refusal to participate to the study and to sign informed consent.

Preoperative data recorded : age, height, weight, ASA physical status, and history of asthma, current smoking (ex-smokers were considered after a 3 month period without smoking), number of pack-years, sign inform consent The day of surgery, randomly allocation (random number table, block sizes of 15) to one of the 3 preoxygenation methods: spontaneous breathing, noninvasive positive inspiratory pressure ventilation (PPV) at 12 centimeters of water (cmH2O) without PEEP or with PEEP at 6 cmH2O (PEEP).

Intravenous line placement and standard monitoring. Preoxygenated through a face mask firmly applied and connected to the anaesthesia machine delivering a fresh gas flow of 12 l min-1. The circle breathing system was previously flushed with the O2 bypass during 30 s before mask placement. The inspired O2 concentration was set at 100%, the inspiratory trigger sensitivity was set at -2 l min-1, the adjustable pressure limiting valve was opened, and maximal airway pressure was limited at 18 cmH2O. Inspired and expired fraction of O2 and carbon dioxide (CO2) were continuously measured. End of the preoxygenation defined by FEO2=90%, intravenous anaesthesia was performed with propofol (2.5 mg kg-1 followed by a continuous administration at 8 mg kg-1 h-1 continuous infusion of propofol to target a bispectral index between 40 and 50), alfentanil 40 microg kg-1, and succinylcholine 1 mg kg-1. No face mask ventilation was provided before orotracheal intubation which was performed at the end of muscles fasciculation. The correct position of the tube (tracheal position above carina) was immediately checked using fiberoptic visualisation and was mandatory before atracurium 0.5 mg kg-1 administration. If tube misplacement occurred, the patient was excluded from the study in order to perform standard care. The time until SpO2 reached 93% was measured. The SpO2 and FEO2 were recorded every 10 s during the preoxygenation phase. The SpO2 was recorded every 10 s during the apnea phase.

Just before leaving the post-anaesthesia care unit, the patient was asked to evaluate the preoxygenation method with the following questions: How do you evaluate the preoxygenation phase on the scale (cursor placed on a 100 mm visual analogue scale) between very comfortable (0 mm) to very uncomfortable (100 mm)? Do you want to have the same preoxygenation method for further anaesthesia (yes/no)? Primary endpoint : time for preoxygenation (average 180 s) calculated from face mask positioning to FEO2=90%.

Secondary endpoints: duration of apnoea from tracheal tube positioning to SpO2 = 93% (average 5 to 10 min), and patient's comfort evaluated on a 0 to 100 mm visual analogue scale.

• Study Type: Interventional
• Enrollment (Actual): 150
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• American Society of Anesthesiologists (ASA) physical status I and II
• Scheduled surgery with general anaesthesia and oro-tracheal intubation

Exclusion Criteria:

• rapid sequence induction
• anticipated difficult mask ventilation
• anticipated difficult intubation
• refusal to participate to the study and to sign informed consent

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: spontaneous breathing (SB); preoxygenation through a face mask firmly applied and connected to the anaesthesia machine delivering a fresh gas flow of 12 l min-1. The inspired O2 concentration was set at 100%. End of preoxygenation FEO2=90%
Experimental: positive pressure ventilation (PPV); PPV : positive pressure ventilation : preoxygenation with noninvasive positive inspiratory pressure ventilation (12 cmH2O) without PEEP. Preoxygenation through a face mask firmly applied and connected to the anaesthesia machine - non invasive inspiratory ventilation mode - inspiratory trigger sensitivity was set at -2 l min-1, the adjustable pressure limiting valve was opened, and maximal airway pressure was limited at 18 cmH2O - PEEP=0 cmH2O End of preoxygenation FEO2=90%	Other: PPV : positive pressure ventilation; Inspiratory pressure support ventilation (12 cmH2O) without PEEP
Experimental: PPV + PEEP; PEEP : PPV + PEEP : preoxygenation with noninvasive positive inspiratory pressure ventilation (12 cmH2O) with PEEP at 6 cmH2O. Preoxygenation through a face mask firmly applied and connected to the anaesthesia machine - non invasive inspiratory ventilation mode - inspiratory trigger sensitivity was set at -2 l min-1, the adjustable pressure limiting valve was opened, and maximal airway pressure was limited at 18 cmH2O - PEEP=6 cmH2O End of preoxygenation FEO2=90%	Other: PEEP : PPV + PEEP; Inspiratory pressure support ventilation (12 cmH2O) with PEEP (6 cmH2O)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time for Preoxygenationfrom Face Mask Positioning to FEO2=90%	Time measured form face mask positioning until FEO2 reached 90% on the gas monitor	up to 5 min

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time Until SpO2=93%	time until SpO2=93% after endotracheal tube placement has been confirmed	up to 10 min
Discomfort of the Preoxygenation Phase Self Reported by the Patient	discomfort of the preoxygenation phase evaluated on a visual analogue scale (0 no discomfort - 100 maximal discomfort) just before PACU leaving	Before PACU leaving

Collaborators and Investigators

• Sponsor: University Hospital, Caen

Publications and helpful links

General Publications

• Hanouz JL, Lammens S, Tasle M, Lesage A, Gerard JL, Plaud B. Preoxygenation by spontaneous breathing or noninvasive positive pressure ventilation with and without positive end-expiratory pressure: A randomised controlled trial. Eur J Anaesthesiol. 2015 Dec;32(12):881-7. doi: 10.1097/EJA.0000000000000297.

Study record dates

Study Major Dates

• Study Start: October 1, 2006
• Primary Completion (Actual): October 1, 2007
• Study Completion (Actual): January 1, 2008

Study Registration Dates

• First Submitted: December 1, 2014
• First Submitted That Met QC Criteria: December 8, 2014
• First Posted (Estimate): December 10, 2014

Study Record Updates

• Last Update Posted (Estimate): April 14, 2016
• Last Update Submitted That Met QC Criteria: March 17, 2016
• Last Verified: March 1, 2016

More Information

Terms related to this study

• Other Study ID Numbers: 2005-39