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Trial registered on ANZCTR


Registration number
ACTRN12614000627651
Ethics application status
Approved
Date submitted
8/06/2014
Date registered
13/06/2014
Date last updated
13/06/2014
Type of registration
Prospectively registered

Titles & IDs
Public title
Comparative efficacy of the CMAC and KingVision videolaryngoscope to conventional direct laryngoscopy in patients with predicted difficult airways
Scientific title
A comparison of intubation difficulty scale (IDS) scores between conventional direct laryngoscopy with the Macintosh blade, to that achieved by the CMAC and KingVision videolaryngoscope in 75 patients at increased risk for difficult tracheal intubation: a randomised, single blind, controlled clinical trial
Secondary ID [1] 284647 0
nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Performance of airway devices 291963 0
Paralyzed and intubated patients for surgery with predictors of a difficult airway 291964 0
Condition category
Condition code
Anaesthesiology 292314 292314 0 0
Anaesthetics

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
After induction of a standard general anaesthetic, and 3 min after administration of a neuromuscular blocking agent, patients underwent indirect laryngoscopy and intubation with the CMAC (Macintosh-shaped reusable videolaryngoscope with separate video screen) or KingVision (channelled disposable videolaryngoscope with built-in video screen atop its handle).
Intervention code [1] 289532 0
Treatment: Devices
Comparator / control treatment
After induction of a standard general anaesthetic and 3 min after administration of a neuromuscular blocking agent, patients underwent conventional direct laryngoscopy and intubation with the classic Macintosh laryngoscope, which does not feature a video screen.
Control group
Active

Outcomes
Primary outcome [1] 292305 0
The intubation difficulty score (IDS) [the sum of 7 variables: number of intubation attempts, operators, use of alternative intubation techniques, glottic exposure, magnitude of lifting force required during laryngoscopy,need for external laryngeal pressure , and position of the vocal cords at intubation ]
Timepoint [1] 292305 0
Assessed at point of intubation of patient's trachea.
Secondary outcome [1] 308683 0
Time to successful tracheal intubation. This is the interval from insertion of the laryngoscope blade into the mouth to when the tracheal tube cuff is inflated after successful intubation.
Timepoint [1] 308683 0
After the laryngoscope has been inserted into the participant's mouth
Secondary outcome [2] 308684 0
Ease of blade and tracheal tube insertion (subjectively assessed from 0:easy, to 100:difficult)
Timepoint [2] 308684 0
At point of intubation of patient's trachea
Secondary outcome [3] 308685 0
The quality of the view (subjectively assessed from 0: good, 100: bad)
Timepoint [3] 308685 0
At point of intubation of patient's trachea
Secondary outcome [4] 308686 0
Successful intubation on first attempt
Timepoint [4] 308686 0
When the laryngoscope has been inserted into the participant's mouth.
Secondary outcome [5] 308689 0
Complications associated with tracheal intubation eg. desaturation (SpO2 <95%), oesophageal intubation, laryngo-pharyngeal morbidity ie. visible lip or dental injury, mucosal injury ( blood on laryngoscope blade).
Timepoint [5] 308689 0
At point of intubation of patient's trachea. An independent observer not involved in the trial assessed these outcomes.

Eligibility
Key inclusion criteria
Patients with at least two of the following characteristics indicative of an increased risk for difficult tracheal intubation: (i) Mallampati classification 3 or 4 (ii) thyromental distance less than and equal to 6cm, (iii) inter-incisor distance less than and equal to 4cm, who are scheduled for gynaecological, breast or plastic reconstructive surgery.All patients with a previously documented difficult tracheal intubation were also eligible for inclusion.
Minimum age
22 Years
Maximum age
90 Years
Gender
Females
Can healthy volunteers participate?
No
Key exclusion criteria
We excluded patients who were ASA physical status IV, at high risk of regurgitation or aspiration.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Eligible participants were interviewed and invited to participate. Sealed, opaque envelopes concealed the group allocation
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
A computer generated random number table
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


Intervention assignment
Parallel
Other design features
Phase
Phase 4
Type of endpoint(s)
Efficacy
Statistical methods / analysis
The primary end-point was IDS scores. Sample size calculation was based on data from previous work comparing intubating characteristics of the Macintosh, Pentax Airway Scope and Glidescope videolaryngoscopes in predicted difficult intubations. On the basis of prior studies in this population, the expected mean IDS score was at least 4, representing moderately difficult intubating conditions, in patients undergoing tracheal intubation with the Macintosh laryngoscope. A 50% reduction in the mean IDS score eg.IDS score of < 2 in patients intubated with videolaryngoscopes was deemed clinically significant. Given an expected standard deviation (SD) of 2.25 from prior studies, at alpha=0.05 and beta =0.2, 24 patients per group would be required. We therefore recruited 25 patients per group.

Data are reported as mean (SD), medians [range] and incidences (both absolute and percentage). The normal distribution of data was tested using the Kolmogorov-Smirnov test. One-way ANOVA analysis was used to assess parametric data including intubation times and haemodynamic parameters. Data for the IDS score, the number of intubation attempts, and the numbers of optimization manoeuvres were analysed using ANOVA or
Kruskal–Wallis ANOVA on ranks as appropriate. When significant differences were encountered, post-hoc pair wise comparison was performed using Bonferroni’s correction. Non-parametric data were evaluated for differences among the groups using a Kruskal-Wallis test. Other categorical and dichotomous variables such as ASA status, Mallampati, preoperative airway parameters like thyromental and inter-incisor distance, cervical spine mobility, Cormack and Lehane grades, differences in number of intubation attempts, use of optimisation manouvres, use of additional adjuncts and airway complications were analyzed using Chi -square tests. All statistical analyses were performed using SPSS 20.0 (SPSS, IBM Chicago, IL). P <0.05 was considered significant.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment outside Australia
Country [1] 6107 0
Singapore
State/province [1] 6107 0

Funding & Sponsors
Funding source category [1] 289375 0
Self funded/Unfunded
Name [1] 289375 0
Dr Wendy H.L. Teoh
Address [1] 289375 0
KK Women’s and Children’s Hospital,
100 Bukit Timah Road, Singapore 229899
Country [1] 289375 0
Singapore
Primary sponsor type
Individual
Name
Dr Wendy H.L. Teoh
Address
KK Women’s and Children’s Hospital,
100 Bukit Timah Road, Singapore 229899
Country
Singapore
Secondary sponsor category [1] 288060 0
None
Name [1] 288060 0
Address [1] 288060 0
Country [1] 288060 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 291139 0
Singhealth Centralised Institutional Review Board D
Ethics committee address [1] 291139 0
Singapore Health Services Pte Ltd,
31 Third Hospital Avenue,
#03-03 Bowyer Block C,
Singapore 168753.
Ethics committee country [1] 291139 0
Singapore
Date submitted for ethics approval [1] 291139 0
Approval date [1] 291139 0
22/05/2014
Ethics approval number [1] 291139 0
CIRB 2014-303-D

Summary
Brief summary
This trial compares intubation characteristics of using
conventional direct Macintosh laryngoscopy vs. the CMac and KingVision videolaryngoscope to intubate the tracheas of 75 patients with difficult airways.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 48610 0
Dr Wendy H.L Teoh
Address 48610 0
Department of Women’s Anaesthesia,
KK Women’s and Children’s Hospital,
100 Bukit Timah Road.
Singapore 229899.
Country 48610 0
Singapore
Phone 48610 0
+65- 63941081
Fax 48610 0
+65- 62912661
Email 48610 0
teohwendy@yahoo.com
Contact person for public queries
Name 48611 0
Dr Wendy H.L Teoh
Address 48611 0
Department of Women’s Anaesthesia, KK Women’s and Children’s Hospital,
100 Bukit Timah Road. Singapore 229899.
Country 48611 0
Singapore
Phone 48611 0
+65- 63941081
Fax 48611 0
+65- 62912661
Email 48611 0
teohwendy@yahoo.com
Contact person for scientific queries
Name 48612 0
Dr Wendy H.L Teoh
Address 48612 0
Department of Women’s Anaesthesia, KK Women’s and Children’s Hospital,
100 Bukit Timah Road. Singapore 229899.
Country 48612 0
Singapore
Phone 48612 0
+65- 63941081
Fax 48612 0
+65- 62912661
Email 48612 0
teohwendy@yahoo.com

No information has been provided regarding IPD availability
Summary results
No Results