ANZCTR - Registration

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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)

Condition category

Condition code

Anaesthesiology

Other anaesthesiology

Oral and Gastrointestinal

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]

Diagnosis / Prognosis

Comparator / control treatment

Spontaneous ventilation(SV)

Control group

Active

Outcomes

Primary outcome [1]

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]

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]

Age will be compared using the unpaired t-test.

Timepoint [2]

Measured at the beginning of surgery.

Primary outcome [3]

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]

Measured at the beginning of surgery.

Primary outcome [4]

Duration of anaesthesia will be compared using the unpaired t-test.

Timepoint [4]

Primary outcome [5]

Duration of surgery is a value in minutes and varies with the type of surgery and skill of the operator.

Timepoint [5]

Primary outcome [6]

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]

Secondary outcome [1]

No secondary outcomes

Timepoint [1]

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?

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

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

Funding & Sponsors

Funding source category [1]

Commercial sector/Industry

Name [1]

LMA PacMed

Address [1]

Country [1]

Australia

Primary sponsor type

Individual

Name

Dr Anil Sen Gupta

Address

Country

Secondary sponsor category [1]

None

Name [1]

Nil

Address [1]

Country [1]

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

Address

Country

Phone

Fax

Contact person for public queries

Name

Dr Anil Sen Gupta

Address

Department of Anaesthetics
Royal Prince Alfred Hospital
Missenden Rd
Camperdown NSW 2050

Country

Australia

Phone

+61 2 95158564

Fax

+61 2 95192455

ajsengupta@yahoo.com.au

Contact person for scientific queries

Name

Dr Anil Sen Gupta

Address

Department of Anaesthetics
Royal Prince Alfred Hospital
Missenden Rd
Camperdown NSW 2050

Country

Australia

Phone

+61 2 95158564

Fax

+61 2 95192455

ajsengupta@yahoo.com.au

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

No additional documents have been identified.

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