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Effects of Spontaneous Breathing Activity on Atelectasis Formation During General Anaesthesia (SBAFGA)

Primary Purpose

Atelectasis

Status
Completed
Phase
Not Applicable
Locations
Germany
Study Type
Interventional
Intervention
Spontaneous Breathing
Pressure Controlled Ventilation
Pressure Support Ventilation
Sponsored by
Technische Universität Dresden
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional supportive care trial for Atelectasis focused on measuring Ventilation, General Anesthesia, electrical impedance tomography, pressure support, spontaneous breathing, laryngeal mask, Patients who are scheduled for elective knee or ankle surgery

Eligibility Criteria

18 Years - 65 Years (Adult, Older Adult)All SexesDoes not accept healthy volunteers

Inclusion Criteria:

  • Patients (age 18-65) scheduled for elective knee or ankle surgery under general anaesthesia with an LMA with an expected duration of at least 60 minutes.

Exclusion Criteria:

  • Pregnancy,
  • Pulmonary diseases (e.g. Asthma, COPD),
  • Implanted pacemaker or AICD,
  • Inability to communicate or understand the risks of the study,
  • Contraindications for an LMA (e.g. obesity, reflux),
  • Deformities of the thorax,
  • Failure to place an LMA.

Sites / Locations

  • University Hospital Carl-Gustav-Carus

Arms of the Study

Arm 1

Arm 2

Arm 3

Arm Type

Other

Other

Other

Arm Label

Spontaneous Breathing

Pressure controlled ventilation

Pressure Support Ventilation

Arm Description

Patients will be breathing spontaneously during anesthesia

Patients in the PPV group will be ventilated by pressure control (tidal volume 8-10 ml/kg, frequency 10-14, I:E 1:1, no PEEP, target CO2 4.5 kPa).

The patients in the PSV group will breathing spontaneously on the ventilator with assistance by inspiratory support pressure. The support pressure will be adjusted to achieve a tidal volume of 8-10 ml/kg.

Outcomes

Primary Outcome Measures

Regional ventilation at the end of anaesthesia and at discharge from PACU compared to baseline values obtained before induction

Secondary Outcome Measures

Differences in spirometry values, oxygenation in the PACU (measured as SpO2 at room air), breathing effort

Full Information

First Posted
February 22, 2010
Last Updated
October 28, 2010
Sponsor
Technische Universität Dresden
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1. Study Identification

Unique Protocol Identification Number
NCT01073917
Brief Title
Effects of Spontaneous Breathing Activity on Atelectasis Formation During General Anaesthesia
Acronym
SBAFGA
Official Title
Effects of Spontaneous Breathing Activity on Atelectasis Formation During General Anaesthesia: A Randomized Clinical Trial
Study Type
Interventional

2. Study Status

Record Verification Date
October 2010
Overall Recruitment Status
Completed
Study Start Date
March 2010 (undefined)
Primary Completion Date
October 2010 (Actual)
Study Completion Date
October 2010 (Actual)

3. Sponsor/Collaborators

Name of the Sponsor
Technische Universität Dresden

4. Oversight

Data Monitoring Committee
No

5. Study Description

Brief Summary
Atelectasis and redistribution of ventilation towards non-dependent lung zones are a common side effects of general anesthesia. Spontaneous breathing activity (SBA) during mechanical ventilation may avoid or reduce atelectasis, improving arterial oxygenation; however, it is unclear whether these effects play a significant role during general anesthesia in patients with healthy lungs. Earlier studies on ventilation during general anesthesia had to rely on computed tomography (CT) findings. Recent advances in lung imaging technology allow to assess the regional aeration of the lungs continuously and non-invasive by electrical impedance technology (EIT). In this work, we will use the EIT to assess ventilation changes from the time before induction of anesthesia until discharge from the post-anesthesia care unit. Our main focus is the difference caused by pure positive pressure ventilation (PCV) and assisted spontaneous breathing (pressure support ventilation, PSV). Our findings would improve our understanding of the physiology of the lungs during general anesthesia and would help to improve the standards of respiratory care during anesthesia
Detailed Description
Atelectasis formation is a common phenomenon during general anaesthesia, occurring in almost 90% of patients (Lundquist, Hedenstierna et al. 1995). In patients in supine position, atelectasis of dorsal lung zones is usually accompanied by redistribution of ventilation towards ventral areas (Hedenstierna 2003; Victorino, Borges et al. 2004).The main mechanisms which contribute to the formation of atelectasis are compression (e.g. in obese patients or during laparoscopic surgery), absorption (e.g. when high concentrations of inspired oxygen are used) and reduced surfactant action(Magnusson and Spahn 2003). Atelectasis impairs oxygenation by reducing the functional residual capacity and by causing right-to-left-shunts. Consecutively, hypoxemia after extubation is common in daily practice: 20% of patients in a study experienced desaturations below 92% (Mathes, Conaway et al. 2001), and the risk is even higher in patients with risk-factors such as obesity or thoraco-abdominal procedures (Russell and Graybeal 1993; Xue, Li et al. 1999). Hypoxemic events prolong the stay in PACU, cause more ICU admissions and increase the incidence of cardiac complications (Rosenberg, Rasmussen et al. 1990; Gill, Wright et al. 1992). Several measures to prevent or treat atelectasis in ventilated patients have been investigated, such as PEEP (Brismar, Hedenstierna et al. 1985; Tokics, Hedenstierna et al. 1987; Neumann, Rothen et al. 1999), recruitment maneuvers (Neumann, Rothen et al. 1999) and spontaneous breathing during mechanical ventilation (Putensen, Rasanen et al. 1994; Putensen, Mutz et al. 1999). The laryngeal mask airway (LMA) is ideally suited for spontaneous breathing during general anaesthesia because of its low resistance. A large survey found that more than half of the routine cases with an LMA are performed under spontaneous ventilation (Verghese and Brimacombe 1996), while positive pressure ventilation is equally acceptable. With regard to the prevention of atelectasis, spontaneous ventilation could be advantageous. Most works on atelectasis formation during general anaesthesia used CT. Although CT is a gold standard for quantification of lung aeration, it can only provide data on single time points and is not suitable for measurements during routine cases. In recent years, the electrical impedance tomography (EIT) has evolved into a versatile tool, which allows detailed insights into ventilation and perfusion conditions of the lung (Bodenstein, David et al. 2009). EIT allows continuous assessment of lung aeration, is non-invasive and can easily be used as a research and monitoring tool during routine cases. We hypothesize that compared with positive pressure ventilation (PPV), pressure support ventilation (PSV) during general anaesthesia reduces the extent of redistribution as detected by EIT during and after the procedure.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Atelectasis
Keywords
Ventilation, General Anesthesia, electrical impedance tomography, pressure support, spontaneous breathing, laryngeal mask, Patients who are scheduled for elective knee or ankle surgery

7. Study Design

Primary Purpose
Supportive Care
Study Phase
Not Applicable
Interventional Study Model
Parallel Assignment
Masking
Participant
Allocation
Randomized
Enrollment
30 (Anticipated)

8. Arms, Groups, and Interventions

Arm Title
Spontaneous Breathing
Arm Type
Other
Arm Description
Patients will be breathing spontaneously during anesthesia
Arm Title
Pressure controlled ventilation
Arm Type
Other
Arm Description
Patients in the PPV group will be ventilated by pressure control (tidal volume 8-10 ml/kg, frequency 10-14, I:E 1:1, no PEEP, target CO2 4.5 kPa).
Arm Title
Pressure Support Ventilation
Arm Type
Other
Arm Description
The patients in the PSV group will breathing spontaneously on the ventilator with assistance by inspiratory support pressure. The support pressure will be adjusted to achieve a tidal volume of 8-10 ml/kg.
Intervention Type
Other
Intervention Name(s)
Spontaneous Breathing
Intervention Type
Other
Intervention Name(s)
Pressure Controlled Ventilation
Intervention Type
Other
Intervention Name(s)
Pressure Support Ventilation
Primary Outcome Measure Information:
Title
Regional ventilation at the end of anaesthesia and at discharge from PACU compared to baseline values obtained before induction
Time Frame
Before, during and after anesthesia
Secondary Outcome Measure Information:
Title
Differences in spirometry values, oxygenation in the PACU (measured as SpO2 at room air), breathing effort
Time Frame
Before, during and after anesthesia

10. Eligibility

Sex
All
Minimum Age & Unit of Time
18 Years
Maximum Age & Unit of Time
65 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
Inclusion Criteria: Patients (age 18-65) scheduled for elective knee or ankle surgery under general anaesthesia with an LMA with an expected duration of at least 60 minutes. Exclusion Criteria: Pregnancy, Pulmonary diseases (e.g. Asthma, COPD), Implanted pacemaker or AICD, Inability to communicate or understand the risks of the study, Contraindications for an LMA (e.g. obesity, reflux), Deformities of the thorax, Failure to place an LMA.
Facility Information:
Facility Name
University Hospital Carl-Gustav-Carus
City
Dresden
State/Province
Saxonia
ZIP/Postal Code
01307
Country
Germany

12. IPD Sharing Statement

Links:
URL
http://anaesthesie-dresden.de/
Description
Department of Anesthesia and Intensive Care Medicine, University Hospital Dresden, Germany

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Effects of Spontaneous Breathing Activity on Atelectasis Formation During General Anaesthesia

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