POST: Comparison of Macintosh Laryngoscope vs Video Laryngoscope in Patients Intubated by Anaesthesia Trainee
Condition: Sore Throat
MeSH terms: Pharyngitis
Study type: Interventional

Summary: 
      OBJECTIVES The objective of this study is to compare the frequency of POST in patients
      intubated by trainee anaesthetist using Video LaryngoscopeTM(VDL) versus Conventional
      Macintosh Laryngoscope (CL) at a tertiary care hospital in Karachi, Pakistan

      OPERATIONAL DEFINITIONS

        1. Sore Throat: A sore throat is pain, scratchiness or irritation of the throat usually
           from irritation or inflammation of the throat (pharynx)(11).

           The visual analogue scale (0-10) will be used to evaluate the severity of sore throat

        2. Trainee Anesthetist: Anesthesia residents level I and II having experience of more than
           six months. They will have to achieve the initial competence of doing intubation under
           direct supervision and need to be familiar with conventional as well as VDL technique.

      HYPOTHESIS:

      NULL HYPOTHESIS: There is no difference in the frequency of POST in patients intubated by
      trainee anaesthetists using VDLTM versus conventional Macintosh laryngoscope.

      ALTERNATE HYPOTHESIS: There is a difference in the frequency of POST in patients intubated by
      trainee anaesthetists using VDLTM versus conventional Macintosh laryngoscope.
    

Detailed description: 
      MATERIAL AND METHODS

      SETTING: The study will be conducted at main Operating Room, Department of Anaesthesiology,
      Aga Khan University Hospital Karachi.

      DURATION OF STUDY: This study will be conducted for a period of one year or till the
      completion of sample size after approval of synopsis by ERC and CPSP.

      SAMPLE SIZE:

      W.H.O software is used to calculate sample size (See Annexure 1) Frequency of POST in VDL
      group = 28% (7) Frequency of POST in CL Group =54% (7) Power of the test = 80% Type I error=
      5% Sample size in each group =55 (Total sample size 110)

      STUDY DESIGN:

      Randomized Control Trial (Observer Blinded)

      SAMPLING TECHNIQUE:

      Non probability consecutive sampling

      DATA COLLECTION: After approval from Ethical Review Committee potential patients will be
      screened in the ward. After eligibility, the consent will be administered by the study
      investigators. If patient agree to participate and signed the consent, he/she will be
      enrolled in the study. Selected patients will be randomly allocated by a computer-generated
      number, either into conventional laryngoscopy (CL) group or video laryngoscopy (VDL) group
      through sealed envelopes. All patients will be managed with general anaesthesia requiring
      control mode ventilation and intubation. The direct supervision of consultant anesthetist
      involved in the study protocol would be there for every case. After instituting routine
      American society of Anaesthesiologist (ASA) recommended monitoring standards, induction of
      anaesthesia would be done by the consultant anaesthetistwith Propofol 1.5-2 mg/Kg, Nalbuphine
      0.1 milligram per Kg and Atracurium 0.5 mg/Kg. The readiness of intubating conditions will be
      judged by orbicular oculi response of train of four stimuli. Patient would be considered
      ready to intubate when there will be no response to the neuromuscular stimuli. The head of
      the patient will be placed in sniffing position with under head pillow to facilitate the
      sniffing position.Selection of VDL or ML will be done as per consecutive sampling. Patient in
      Macintosh laryngoscopy group (MLG) are going to be intubated by trainee anaesthetist as
      defined by operational definition with laryngoscope size 3 or 4 blade as per the decision.
      Similarly the patient in (VLG) will be intubated by trainee anaesthetist as defined earlier
      with laryngoscope size 3 or 4 as per decided plan. Intubation will be done by trainee
      anaesthetist using appropriate size of endotracheal tube (ETT).The size 7-7.5 mm ID would be
      used for adult females, while male patients will require size 8-8.5 mm ID of ETT. All ETT
      tubes will be lubricated with water-based gel (Aplicare Lubricating Jelly) before intubation.
      Number of attempts of Laryngoscopy will be noted along with the time taken if less than or
      greater than 30 seconds also if any alteration like bougie was used. The inflation of the
      cuff would be guided by any obvious leak as measured by the APL bag valve pressure of 20 mm
      Hg. Later on inflation of cuff pressure would also be confirmed by pressure manometer. The
      cuff pressure between 20-25 mm Hg is said to be adequate. The intubation time including the
      number of intubation attempts or any other maneuver used to aid the intubation will be noted
      down. Orogastric tube lubricated by water based gel (Aplicare Lubricating Jelly) will be
      passed in all patients. Number of attempt in passing Orogastric Tube or if the aid of Magill
      forceps used will be noted.All patients would be positioned supine initially and then head up
      (reverse trandelenberg), as per surgeons preference which is usual for laparoscopic general
      surgical procedures Anesthesia will be maintained with Isoflurane in mixture of O2/Air. Dual
      antiemetic prophylaxis that is dexamethasone 0.1 mg/Kg at start and Ondansteron 0.1 mg/Kg at
      the end would be used for every patient. Endotracheal tube cuff pressurewill be regularly
      checked at 30 mins interval. Patient will be excluded if the duration of surgery exceeds one
      hundred and fifty minutes. Patient will be reversed from anaesthesia when fully recovered
      from paralytic effect of Atracurium. This again will be judge by twitch monitoring. All
      patients will be extubated as guided by the subjective and objective criteria of extubation.
      Reversal of neuromuscular paralysis will again be assessed by twitch response to train of
      four stimuli at orbicularis oculi muscle. Patient would be given reversal once all four
      twitches would be there. Patient would be observed for postoperative sore throat at 1, 12 and
      24 hours post operatively by the primary investigator who is blinded to the group allocation.
      The visual analogue scale (0-10) will be used to evaluate the severity of sore throat. The
      definite measurement of POST will be taken at 24 hours.

      ADVERSE EVENTS MANAGEMENT In investigators opinion, there would be no adverse event related
      to the trial protocol. However, if any event either serious or non-serious happened then will
      be reported to the ERC and other relevant entities are per institutional guidelines.

      DATA ANALYSIS: All statistical analysis will be performed using statistical packages for
      social science version 19 (SPSS Inc., Chicago, IL). Mean and standard deviation will be
      computed for age, weight, height, BMI. Frequency and percentage will be computed for gender,
      mallampatti grade, Type of Laryngoscope, Alteration of airway management at intubation,
      Cormack &Lehane intubation grade, Number of attempts of Laryngoscopy and sore throat (at 1
      hr., 12 and 24 hrs.). Both groups will be compared by Chi-square test for frequency of POST
      between both groups, P value ≤0.05 will be considered significant.

      Stratification analysis will be performed to observe effect of confounding variables like
      age, BMI, gender, mallampatti grade, Type of Laryngoscope, Alteration of airway management at
      intubation, Cormack & Lehane intubation grade, duration of intubation and number of attempts
      of Laryngoscopy. After stratification Chi-square test will be applied to compare POST between
      groups. p≤0.05 will be considered significant

      DATA MANAGEMENT AND STORAGE Data will be stored in lock and key and no one will access other
      than study investigators. Electronic data would be password protected. Data will be stored
      for 15 years as per GCP and other regulatory guidelines. Data will be frequently monitored by
      PI for quality checks and queries will be resolved timely basis.
    

Intervention name(s): Video Laryngocope; Macintosh Conventional Laryngocope
Intervention type(s): Device; Device
Intervention description(s): VDL used for VDL arm; Used for Conventional laryngocope arm
Other intervention name(s): Conventional Laryngocope
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Randomized Control Trial (Observer Blinded)
Masking: Double (Participant, Investigator)
Primary purpose: Prevention
Keywords: Video Laryngoscope; Macintosh Laryngocsope; VDL; Karl Storz Video Laryngoscope; Intubation; Post Operative Sore Throat; Anaesthesia Trainee