To Compare Videolaryngoscope Against Direct Laryngoscope for Intubation When Powered Air Purifying Respirator is Worn
Condition: Coronavirus Infection; Ventilatory Failure; Anesthesia Intubation Complication
MeSH terms: Coronavirus Infections; Hypoventilation
Study type: Interventional

Summary: 
      Various guidelines for endotracheal intubation (insertion of breathing tube for mechanical
      ventilation) of Coronavirus Disease 2019 (COVID-19) patients recommend the use of
      videolaryngoscope (medical device used for intubation that has a camera to visualize the
      vocal cords between which the breathing tube will pass) over direct laryngoscope
      (conventionally-used medical device for intubation that depends on anesthetist's direct
      visualization of vocal cords). The reasons for this recommendation are to maximize the
      distance between the medical personnel and the patient's face during intubation to decrease
      the risk of viral particles transmission and to improve intubation success.

      For patients infected with COVID-19, Powered Air Purifying Respirator (PAPR) is recommended
      as an alternative to N95 masks during aerosol-generating procedures such as intubation
      because N95 masks may not fully protect medical personnel from viral transmission during
      intubation.

      There is no evidence to suggest that videolaryngoscope (VL) is superior to direct
      laryngoscope (DL) for intubation when PAPR is donned.

      The purpose of this study is to determine if McGrath VL is superior to DL for intubation when
      the anesthetist is wearing a PAPR. The investigators' hypothesis is that McGrath VL will
      decrease the time to intubation by 20 seconds and more compared to DL when PAPR is donned.
      The investigators also hope to learn if there is any difference in the difficulties
      encountered between the use of VL and DL.
    

Detailed description: 
      Background:

      17% of patients with Coronavirus Disease 2019 (COVID-19) may require endotracheal intubation
      for mechanical ventilation due to respiratory failure.

      Various guidelines for endotracheal intubation of COVID-19 patients recommend the use of
      videolaryngoscope (VL) over direct laryngoscope (DL). The reasons for this recommendation are
      to firstly, maximize the distance between the medical personnel and the patient's face during
      intubation in order to decrease the risk of viral particles transmission and secondly, to
      improve intubation success.

      There is a lack of evidence to show that VL can decrease the risk of contact with aerosol
      generated during intubation. Matthew T.V. Chan et al have shown that aerosol may be generated
      up to 45cm away from the patient's face during intubation. In the investigators' own trial
      run of an experimental set-up to study the difference in intubation between VL and DL when
      PAPR is worn, the investigators found that it is not possible to maintain a distance of at
      least 45cm during the intubation process because of the need to visualize the entry of the
      laryngoscope blade into the patient's mouth in order to prevent injury to the oral
      structures. The investigators' study is congruent with a recent study that reports the mean
      distance from the patient's mouth to anesthetist's mouth was 35.6cm using VL and 16.4cm using
      DL.

      In routine intubations, VL is recommended over DL for endotracheal intubation as it may
      provide a higher success and faster speed of intubation compared to DL. For patients infected
      with COVID-19, PAPR is recommended as an alternative to N95 masks during aerosol-generating
      procedures such as intubation because N95 masks may not fully protect medical personnel from
      viral transmission during intubation. There is currently no evidence to suggest that VL is
      superior to DL for intubation when PAPR is donned.

      Proposed Study Design:

      This study will be a randomized controlled trial. Informed consent to take part in the study
      will be taken from patients who are planned for elective surgery requiring endotracheal
      intubation and also from a group of anesthetists in the department.

      Prior to a consented patient turning up for the operation, randomization will be done to
      determine who from the selected group of anesthetists will be doing the intubation. The
      randomly selected anesthetist will wear the PAPR and intubate the patient using either a DL
      or McGrath VL that the anesthetist is randomized to.

      Hypothesis and Objectives:

      The hypothesis is that McGrath VL will decrease the time to intubation (TTI) by 20 seconds
      and more compared to DL when PAPR is donned. The investigators will also study the secondary
      outcomes between McGrath VL and DL which are first attempt success percentage, use of
      adjuncts, success or failure at intubation using initial laryngoscope that the anesthetists
      is randomized to, intubation difficulty scale (IDS), closest distance from patient's mouth to
      anesthetist's mouth during intubation, adverse events and inability to intubate despite all
      efforts by the anesthetist.

      Sample size calculation:

      The primary outcome of this study is the difference in time to complete intubation between DL
      and VL with hooded PAPR. In a previous study reported by Dong et al in 2013, 21 the median
      (IQR) time to complete tracheal intubation with suited VL was 18.2 (22.1 - 15.1 = 7.0)
      seconds, whereas that for suited DL was 26.4 (35.2 - 23.1 = 12.1) seconds.

      For a normal distribution, the IQR which covers the middle 50% of the whole distribution is
      approximately equal to mean +/- 0.6 standard deviation (SD), or equivalently 1.2 SD. If time
      to complete intubation is normally distributed, the SD for suited VL and suited DL are
      approximately 5.8 and 10.1 seconds, respectively. To be conservative in calculating the
      sample size, the larger SD of 10.1 seconds for suited DL is used. Moreover, the distribution
      of time to complete intubation is unlikely normal but skewed, an inflated SD is assumed to
      compensate for the violation of normal distribution. Hence, a SD of 18 seconds is used.

      The minimal clinically important difference (MCID) for time to complete intubation in
      comparing different laryngoscopes is not defined in the literature. MCIDs ranging between 10
      and 20 seconds to compare intubation times using different laryngoscopes are commonly used,
      in this study a difference of 20 seconds is assumed. Therefore, to detect a difference of at
      least 20 seconds between the suited DL and suited VL groups, targeting a power of 80% and a
      2-sided type I error of 5%, a sample size of 14 patients is required for each group (that is
      a total of 28 patients for the study).

      The investigators will attempt to recruit 50 patients at the Pre-operative Evaluation Clinic
      (PEC) to account for a possible drop-out rate of 40% (either from patient refusal to take
      part in the study on the day of operation or from other unforeseen reasons why
      earlier-recruited patients will not be taking part in the study).

      The investigators will recruit 10 anesthetists from the Division to increase the chance that
      the randomly selected anesthetist is available on the day of operation for a patient who has
      consented for the study.

      Statistical analysis:

      Data will be analyzed with an intention-to-treat analysis. To study the difference in TTI
      between McGrath VL and DL, the investigators will compare the mean or median time of for
      intubation with McGrath VL against DL using Mann-Whitney U test or Independent Samples T-test
      depending on the normality of the distribution.

      To study the difference in the first-attempt success rate, use of adjuncts at first attempt,
      use of adjuncts at subsequent attempts, success or failure at intubation using initial
      laryngoscope randomized to, adverse events (oxygen desaturation to less than 88%, oro-dental
      injuries) and inability to intubate despite all measures between McGrath VL and DL,
      Chi-square test will be used. The investigators will compare the mean or median IDS for
      McGrath VL against that for DL and the mean or median of the closest distance between the
      patient's mouth and the anesthetist's mouth during intubation for McGrath VL against that for
      DL using Mann-Whitney U test or Independent Samples T-test depending on the normality of the
      distribution.

      Quality assurance plan:

      All data will be monitored and reviewed by the PI or Co-investigators. Training will be given
      to the clinical research coordinator for data extraction and entry to the case report forms
      for analysis will be verified by a second person from the study team. Records for all
      participants, including case report forms, all source documentation (containing evidence to
      study eligibility, history and physical findings, laboratory data, results of consultations,
      etc.) as well as Centralized Institutional Review Board (CIRB) records and other regulatory
      documentation will be retained by the PI and be accessible for inspection and copying by
      authorized authorities. The research data will be kept in the secure location within the
      departmental office for 7 years before being destroyed.

      Safety monitoring:

      Serious adverse event (SAE) in relation to human biomedical research, means any untoward
      medical occurrence as a result of any human biomedical research which:

        -  results in or contributes to death

        -  is life-threatening

        -  requires in-patient hospitalization or prolongation of existing hospitalization

        -  results in or contributes to persistent or significant disability/incapacity or

        -  results in or contributes to a congenital anomaly/birth defect

        -  results in such other events as may be prescribed Adverse event (AE) in relation to
           human biomedical research means any untoward medical occurrence as a result of any human
           biomedical research which is NOT serious. Adverse event can be any unfavorable and
           unintended sign (including an abnormal laboratory finding), symptom, or disease
           possibly/ probably/ definitely associated with the participant in the human biomedical
           research.

      Only related SAEs (definitely/ probably/ possibly) will be reported to CIRB. Related means
      there is a reasonable possibility that the event may have been caused by participation in the
      research.

      The investigator is responsible for informing CIRB after first knowledge that the case
      qualifies for reporting. Follow-up information will be actively sought and submitted as it
      becomes available.

      Related AEs will not be reported to CIRB. However, the investigator is responsible to keep
      record of such AEs cases at the Study Site File.

      Safety analyses and interim analyses will be done after 14 patients have completed the study
      to determine the incidence of adverse events. If there are more than 3 patients with adverse
      events, the investigators will review the safety of the study and decide if there is need to
      improve on the study design or terminate the study prematurely.
    

Intervention name(s): McGrath videolaryngoscope; Direct laryngoscope
Intervention type(s): Device; Device
Intervention description(s): A brand of a commonly-used videolaryngoscope which has a camera at the end of the laryngoscope to visualize the vocal cords; Classic direct laryngoscope that depends on visualization of the vocal cords by the operator
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Randomized controlled trial. Prior to a consented patient turning up for his/her operation, randomization will be done to determine who from the selected group of anesthetists will be doing the intubation. The randomly selected anesthetist will wear the PAPR and intubate the patient using either a DL or McGrath VL that he/she is randomized to.
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Intubation; Direct laryngoscope; Video laryngoscope; Personal protective equipment; Powered Air Purifying Respirator; Coronavirus Disease 2019