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NCT Number: NCT02548416

Peroperative Use of Positive End-expiratory Pressure Prevents Formation of Atelectasis as Studied by Computerised Tomography at End of Surgery

Atelectasis is common during and after general anaesthesia and a number of interventions have been suggested in order to prevent their formation. The use of Positive End Expiratory Pressure (PEEP) during general anaesthesia has in recent years been questioned.

The investigators hypothesize that the use of PEEP as a single intervention improves oxygenation and prevents atelectasis as investigated by computed tomography compared to a control group with zero PEEP.

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Key information

Conditions

Atelectasis Lung Diseases Pulmonary Atelectasis Respiratory Tract Diseases

Age range

40 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Region Västmanland

Köping, Sweden

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy subjects, American Society of Anesthesiology (ASA) I-II.
  • Patients scheduled for non-abdominal day case surgery under general anaesthesia.

Exclusion criteria

  • ASA class III or higher.
  • Body Mass Index (BMI) 30 or higher.
  • Arterial oxygen saturation (SpO2) <96% breathing air.
  • Chronic Obstructive Pulmonary Disease (COPD).
  • Ischaemic heart disease.
  • Known or anticipated difficult airway.
  • Active smokers and ex-smokers with a history of more than 6 pack years.
  • Need for interscalene or supraclavicular plexus block for postoperative pain relief (risk of phrenic nerve paralysis).

Treatment and study plan

positive end-expiratory pressure

Procedure

Induction of anaesthesia is performed in a conventional manner using a target controlled infusion of propofol and remifentanil. Intubation of the trachea is facilitated by rocuronium.

As soon as correct position of the endotracheal tube is confirmed, controlled ventilation is started with a tidal volume of 7 mL/kg body weight and a respiratory frequency of 10. The fresh gas flow is set to 1 litre/min with an oxygen mixture of 40%, aiming for an inspired oxygen fraction (FiO2) of 30-35%. Positive end-expiratory pressure is set to 6 or 8 cm H20 (8 if BMI>25) in the intervention group.

Unless the patient´s SpO2 falls below 90%, the FiO2 remains unchanged throughout the procedure.

Control group, zero PEEP

Procedure

Induction of anaesthesia is performed in a conventional manner using a target controlled infusion of propofol and remifentanil. Intubation of the trachea is facilitated by rocuronium. As soon as correct position of the endotracheal tube is confirmed, controlled ventilation is started with a tidal volume of 7 mL/kg body weight and a respiratory frequency of 10. The fresh gas flow is set to 1 litre/min with an oxygen mixture of 40%, aiming for an inspired oxygen fraction (FiO2) of 30-35%. Zero PEEP is used.

Unless the patient´s SpO2 falls below 90%, the FiO2 remains unchanged throughout the procedure.

Primary outcomes

  1. Area of atelectasis expressed as centimeter^2

    Time frame: Within 1-2 hours, just before emergence from anesthesia.The outcome measure (atelectasis) will be investigated at just one point i.e. end of surgery but before emergence from anaesthesia.

    The area of atelectasis in the lungs is assessed by computed tomography (CT) 5-10 mm above the dome of the right diaphragm and expressed in centimeter^2 and as a percentage of the total lung area in the particular scan.

  2. Measurement of aeras with different aeration in the particular CT scan.

    Time frame: Within 1-2 hours, just before emergence from anesthesia.The outcome measure (atelectasis) will be investigated at just one point i.e. end of surgery but before emergence from anaesthesia.

    The areas of different aeration are assessed by computed tomography (CT) 5-10 mm above the dome of the right diaphragm and expressed in centimeter^2 and as a percentage of the total lung area in the particular scan.

Secondary outcomes

  1. Oxygenation, oxygen tension in arterial blood expressed in kilo Pascal (kPa)

    Time frame: Within 1-2 hours, just before emergence from anesthesia. At end of surgery but before emergence from anaesthesia, at the same time as the lungs are investigated by computed tomography.

    Arterial blood gas samples will be drawn and analyzed at the same time as the computed tomography scan will be undertaken.

  2. Oxygenation, oxygen tension in arterial blood expressed in kilo Pascal (kPa)

    Time frame: Within 2 hours perioperatively, 15 minutes after extubation.

    Arterial blood gas samples will be drawn and analyzed 15 minutes after emergence from anesthesia and extubation.

Sponsors and collaborators

Lead sponsor

Region Västmanland

Other

Registry information

Important dates

Study start
2015
Primary completion
2016
Study completion
2016
First posted
Sep 14, 2015
Registry last updated
Nov 21, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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