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Trial registered on ANZCTR


Registration number
ACTRN12606000225516
Ethics application status
Not yet submitted
Date submitted
21/05/2006
Date registered
5/06/2006
Date last updated
5/06/2006
Type of registration
Prospectively registered

Titles & IDs
Public title
Does the design of the Proseal reduce the incidence of gastro-oesophageal reflux?
Scientific title
Comparison of the incidence of gastro-oesophageal reflux with the ProSeal laryngeal mask airway in spontaneous ventilating verses controlled ventilating patients undergoing general anaesthesia for elective surgery.
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Gastro-oesophageal Reflux (GOR) 1203 0
Condition category
Condition code
Anaesthesiology 1287 1287 0 0
Other anaesthesiology
Oral and Gastrointestinal 1288 1288 0 0

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The laryngeal mask airway (LMA) is used for management of the airway during general anaesthesia. A limiting factor with the use of the laryngeal mask airway (LMA) is the lack of airway protection from regurgitated gastric contents.
The ProSeal laryngeal mask airway (PLMA) has a double cuff design resulting in a higher airway seal pressure and an independent drain tube that opens at the upper oesophageal sphincter. The higher airway seal pressure allows the administration of Intermittent positive pressure ventilation (IPPV) without gas leakage. We propose to insert a pH catheter into the oesophagus via the independent drainage tube of the ProSeal laryngeal mask airway (PLMA) to look for changes in pH indicating gastro oesophageal reflux (GOR) during general anaesthesia.
Patients presenting for elective surgery which does not require paralysis or tracheal intubation will be invited to participate in the study.
Forty patients will be randomly assigned to one of two groups, spontaneous ventilation(SV) or intermittent positive pressure ventilation (IPPV).
The pH catheter will remain insitu for the duration of the surgery. At the completion of the case the patient will be woken and the pH catheter and ProSeal laryngeal mask airway (PLMA) removed.
Intervention code [1] 1061 0
Diagnosis / Prognosis
Comparator / control treatment
Spontaneous ventilation(SV)
Control group
Active

Outcomes
Primary outcome [1] 1748 0
A gastro oesophageal reflux (GOR) episode is defined as a decrease in pH to less than 4.

A Zinetics 24ME multi-use pH catheter will be advanced through the drainage port of the Proseal laryngeal mask airway (PLMA). The electrode will be advanced into the stomach which will be confirmed by pH levels of less the 3. It will then be slowly withdrawn to the gastro-oesophageal junction, the site being indicated by an abrupt increase in the pH recorded to levels above 5. It will then be withdrawn a further 4-5cm to be positioned at the mid-oesophagus.

The probe will be connected to a Digitrapper 100 pH monitoring device which records oesophageal pH every 4 seconds.

At the completion of the case the patient will be woken and the pH catheter and ProSeal laryngeal mask airway (PLMA) removed.
Timepoint [1] 1748 0
Oesophageal pH will be measured throughout the duration of the surgery, every 4 seconds, from the point of insertion of the probe at the beginning of the case until the removal of the probe at the completion of the surgery.
Primary outcome [2] 1749 0
Age will be compared using the unpaired t-test.
Timepoint [2] 1749 0
Measured at the beginning of surgery.
Primary outcome [3] 1750 0
Body Mass Index (BMI) will be compared using the unpaired t-test.

BMI is a measure of persons height scaled to their weight. BMI = weight in kilograms divided by height in meters squared.
Timepoint [3] 1750 0
Measured at the beginning of surgery.
Primary outcome [4] 1751 0
Duration of anaesthesia will be compared using the unpaired t-test.
Timepoint [4] 1751 0
Primary outcome [5] 1752 0
Duration of surgery is a value in minutes and varies with the type of surgery and skill of the operator.
Timepoint [5] 1752 0
Primary outcome [6] 1753 0
A gastro oesophageal reflux (GOR) episode is defined as a decrease in pH to less than 4. pH will be sampled every 4 seconds for the duration of the case. Therefore a pH measure of less than 4 during the case = an episode of reflux.

The incidence of reflux will be analysed using Fisher’s exact test. Using a predicted incidence of gastro oesophageal reflux (GOR) of 30% and 5% in the intermittent positive pressure ventilation (IPPV) and spontaneous breathing patients respectively, power analysis suggests that a sample size of 30 patients for each group will be adequate to have an 80% chance of detecting a statistically significant difference. A p value of less than 0.05 will be taken as statistically significant.
Timepoint [6] 1753 0
Secondary outcome [1] 3102 0
No secondary outcomes
Timepoint [1] 3102 0

Eligibility
Key inclusion criteria
Patients presenting for elective surgery.- Male and female- Healthy or only mild systemic illness (American Society of Anesthesiologists [ASA] grade I or II).
Minimum age
18 Years
Maximum age
Not stated
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Unable or decline to give consent- Patient in prone position for surgery- Body mass index > 30kg.m-3- Pre-existing pH or gastric anatomical problemso History of GORo Receiving medications that might effect pH or motilityo Previous upper gastro intestinal surgeryo Hiatus hernia.

Study design
Purpose of the study
Diagnosis
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Coin-tossing
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Type of endpoint/s
Safety
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
20/06/2006
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
60
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 1414 0
Commercial sector/Industry
Name [1] 1414 0
LMA PacMed
Country [1] 1414 0
Australia
Primary sponsor type
Individual
Name
Dr Anil Sen Gupta
Address
Country
Secondary sponsor category [1] 1240 0
None
Name [1] 1240 0
Nil
Address [1] 1240 0
Country [1] 1240 0

Ethics approval
Ethics application status
Not yet submitted

Summary
Brief summary
On arrival to the anaesthetic room patients will have non-invasive monitoring established and a venous access line placed under local anaesthesia prior to induction of general anaesthesia. Following pre-oxygenation of the patient, induction of anaesthesia will be carried out by the anaesthetist in charge of the case. Intravenous fentanyl (2mcg.kg-1), followed by an induction dose of propofol (1-3mg.kg-1) will be given. The patients allocated to the IPPV group will be given intravenous rocuronium (0.6mg.kg-1). Once an adequate depth of anaesthesia has been reached a ProSeal laryngeal mask airway (PLMA) will be inserted as per the manufactures recommended technique. Anaesthesia will be maintained on 2% sevoflurane in 0.5 litre.min-1 oxygen and 1 litre.min-1 nitrous oxide for both spontaneous breathing and intermittent positive pressure ventilation (IPPV) patients. Intermittent positive pressure ventilation (IPPV) will be delivered with a tidal volume of 10ml.kg-1 and a respiratory rate of 8-14 breaths per minute.
A Zinetics 24ME multi-use pH catheter with external reference electrode will then be advanced through the drainage port of the ProSeal laryngeal mask airway (PLMA). The electrode will be advanced into the stomach which will be confirmed by pH levels of less the 3. It will then be slowly withdrawn to the gastro-oesophageal junction, the site being indicated by an abrupt increase in the pH recorded to levels above 5. It will then be withdrawn a further 4-5cm to be positioned at the mid-oesophagus.
At the completion of the case the patient will be woken and the pH catheter and ProSeal laryngeal mask airway (PLMA) removed.
The investigator will be blinded to all pH measurements following the insertion of the catheter.
The recording will be subsequently transferred to a computer to be analysed with Polygram 98 Diagnostic Workstation software by an investigator blinded to the anaesthetic technique.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 35253 0
Address 35253 0
Country 35253 0
Phone 35253 0
Fax 35253 0
Email 35253 0
Contact person for public queries
Name 10250 0
Dr Anil Sen Gupta
Address 10250 0
Department of Anaesthetics
Royal Prince Alfred Hospital
Missenden Rd
Camperdown NSW 2050
Country 10250 0
Australia
Phone 10250 0
+61 2 95158564
Fax 10250 0
+61 2 95192455
Email 10250 0
[email protected]
Contact person for scientific queries
Name 1178 0
Dr Anil Sen Gupta
Address 1178 0
Department of Anaesthetics
Royal Prince Alfred Hospital
Missenden Rd
Camperdown NSW 2050
Country 1178 0
Australia
Phone 1178 0
+61 2 95158564
Fax 1178 0
+61 2 95192455
Email 1178 0
[email protected]

No information has been provided regarding IPD availability


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
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