Anesthesia, General, Patient Positioning, Respiratory Function Tests, Ventilation
Conditions
Keywords
Respiratory Function, Patient Positioning, anesthesia
Brief summary
General anesthesia has been demonstrated to have a negative impact on lung function. Both surgery and patient position influence the perioperative lung function. Laryngeal mask airway (LMA) has been proved to be safe and efficient to maintain the airways patent during general anesthesia. Pressure support ventilation (PSV) with LMA is routinely used in clinical practice. The aim of the present trial is to characterize perioperative changes in lung volume, ventilation inhomogeneity and respiratory mechanics in patients in the lithotomy position and spontaneously breathing through LMA with and without PSV.
Detailed description
This study is a randomized controlled trial. Participants for this study will be recruited from the Gynecological department of the University Hospitals of Geneva, scheduled for gynecological procedures in the lithotomy position under general anesthesia. A total of 40 patients will be enrolled and randomly assigned into 2 groups: Group SB (spontaneously breathing without PSV) and Group PSV (spontaneously breathing with PSV). Measurements of end-expiratory lung volume (EELV) and ventilation inhomogeneity will be performed in all patients with a nitrogen multiple breath washout method, before and 1 hour after surgery. Similarly, airway resistance (Rrs) and reactance (Xrs) will be measured at the same time by using the Forced Oscillation Technique. The primary endpoint: Perioperative changes in ventilation inhomogeneity (LCI) and respiratory mechanics (Rrs and Xrs) of patients, positioned in lithotomy and undergoing general anesthesia while breathing spontaneously through LMA with or without PSV. The secondary endpoints: Presence of respiratory complications, oxygen need in the recovery room, length of stay in the recovery room and in the hospital. Correlation between duration of positioning and surgery with lung function and volume measurements. Relevance: There are no studies that addressed the value of pressure support ventilation to overcome the potential changes in lung function following spontaneous ventilation across a LMA in the lithotomy position.
Interventions
PROCEDUREgeneral anesthesia across LMA
general anesthesia across LMA
PROCEDURESpontaneous breathing(SB)
general anesthesia across LMA under SB without PSV
PROCEDUREPressure Support Ventilation
general anesthesia across LMA under SB with PSV
Sponsors
Walid HABRE
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 50 Years
Healthy volunteers
No
Inclusion criteria
\- American Society of Anesthesiologists physical status (ASA) Ⅰ and Ⅱ grade, adult female patients, aged between 18 and 50 years scheduled for elective gynecological surgery in the lithotomy position.
Exclusion criteria
1. Age\<18 years and \>50 years old 2. ASA score of III-V 3. Patients with a potentially difficult airway (cervical spine disease, Mallampati classification III or IV or mouth opening of \<2.5 cm) 4. Risk of regurgitation/aspiration(previous upper gastrointestinal tract surgery, known or symptomatic hiatus hernia, oesophageal reflux, peptic ulceration or not fasted) 5. Respiratory diseases(bronchial asthma requiring therapy) 6. Patient refusal 7. Malignant hyperthermia history 8. Sore throat within 10 days 9. Body mass index (BMI) \>30 kg/m2 10. Cardiac disease associated with dyspnea more than New York Heart Association II 11. Severe psychiatric disorder.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Perioperative changes in ventilation inhomogeneity (LCI) | Through study completion, an average of 12 hours | LCI will be derived from the nitrogen multiple breath washout technique that will be applied before and after general anesthesia for gynecology in the lithotomy position with patients breathing spontaneously through a LMA with and without pressure support. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Alterations in end expiratory lung volume in ml/kg (EELV) | Through study completion, an average of 12 hours | EELV will be measured from the nitrogen multiple breath washout technique that will be applied before and after general anesthesia for gynecology in the lithotomy position with patients breathing spontaneously through a LMA with and without pressure support. |
| Changes in respiratory system compliance (Crs) | Through study completion, an average of 12 hours | Crs will be measured by the forced oscillation technique |
| Changes in airway resistance (Raw) | Through study completion, an average of 12 hours | Raw will be measured by the forced oscillation technique |
| Perioperative respiratory complications | Through study completion, an average of 12 hours | any respiratory complications (apnoea/ bradypnoea, bronchospasm, laryngospasm, oxygen desaturation \<90%/ hypoxemia, hypoventilation/ atelectasis, pulmonary embolism, cough and /or airway obstruction |
Countries
Switzerland
Outcome results
None listed