Difficult Bag Mask Ventilation and Difficult Intubation in Children
Condition: Inadequate or Impaired Breathing Pattern or Ventilation; Difficult Intubation; Anesthesia; Adverse Effect
MeSH terms: Respiratory Aspiration
Study type: Observational

Summary: 
      Unanticipated difficult airway comprises of unexpected difficult bag mask ventilation or
      unforeseen difficult laryngoscopy. The incidence of difficult laryngoscopy or unanticipated
      difficult intubation in children was varied from 1.2 %to 4.77% depending on general or
      specific population and type of surgery. The known risk factors of difficult intubation in
      children were young age, associated syndrome or congenital abnormality and obstructive sleep
      apnea. Moreover, the predictors of difficult laryngoscopy by physical examination were
      associated with short interincisors distance, high frontal plane to chin distance, short
      thyromental distance and Cormack & Lehane classification 3 or 4. However, little knowledge is
      known regarding difficult bag mask ventilation in children. The incidence of difficult bag
      mask ventilation was 6.6% according to the single study. A few study reported the independent
      risk factor of difficult bag mask ventilation in children which were young age, obesity, use
      of neuromuscular blocking agent and airway surgery. In addition, the association between
      difficult bag mask ventilation and difficult intubation are still unknown. To understand more
      of difficult bag mask ventilation in children and factor-association may reduce incidence of
      morbidity and mortality by identifying difficult airway, preparing personnel and equipment
      tool in order to improve clinical outcome in pediatric anesthesia. The objectives of the
      study were to determine the predictors of difficult bag mask ventilation and the association
      with unexpected difficult intubation in children who came for elective surgery in tertiary
      care hospital of southern Thailand.
    

Detailed description: 
      Study protocol and anesthesia practice Patient's demographic and history of snoring or
      asthma/hyper-reactive airway were obtained by research assistant at preinduction period.
      Standard monitoring including non-invasive blood pressure, pulse oximetry,
      electrocardiography and capnography were applied to all patients before starting general
      anesthesia. All patients were received general anesthesia with oroendotracheal tube
      intubation. Induction techniques were either inhalation anesthetic agent by
      N2O-O2-sevoflurane or intravenous agent with 100% O2. Type of anesthetic circuit used (Circle
      or Jackson-Rees) was depending on anesthesiologist in charge. Patients head position were in
      neutral under small head ring to prevent head movement during induction. Maneuvers on bag
      mask ventilation such as application of CPAP with opening airway maneuvers, oropharyngeal
      airway or two person ventilations were recorded by research assistant at induction period.
      When positive pressure ventilation was difficult after the patients had been slept, the CPAP
      ≥5 cmH2O was applied incorporated with opening airway by head tilt/chin lip or jaw thrust
      until assisted spontaneous ventilation was successful. BMV was performed during induction
      with 100% O2. If performing BMV was possible, a non-depolarizing muscle relaxant was
      administered to facilitate the laryngoscopy procedure. If performing BMV was difficult, deep
      anesthesia using propofol, or a non-depolarizing muscle relaxant, or succinylcholine was
      given to facilitate the BMV procedure. The anesthesia personnel who handled the BMV also
      performed the first laryngoscopy. The laryngoscopists included anesthesia residents (more
      than 1-year experience), nurse anesthetists (at least 1-year training), and anesthesiologist
      attendants. Number of intubation attempts, Cormack-Lehane laryngoscopic view, intubation time
      in second and presence of desaturation (SpO2 < 95%) were recorded by research assistant at
      intubation period. There were many optioned used to aid successful intubation such as
      applying BURP maneuver, endotracheal tube with stylet used, change to smaller endotracheal
      tube size, change laryngoscope type or change to more experience laryngoscopists. Attending
      anesthesiologists take responsibility over anesthesia resident and nurse anesthetists for
      first or second failure of intubation attempts.

      Outcome of interest Primary outcomes were to determine the predictors of difficult bag mask
      ventilation. The difficult bag mask ventilation was defined as the occurrence at least 2
      following events which were requiring application of CPAP with opening airway maneuvers,
      requiring oropharyngeal airway or nasopharyngeal airway, requiring 2- person bag mask
      ventilation, unable to perform bag mask ventilation or presence of desaturation (SpO2 < 95%).

      Secondary outcome was to find out the association between difficult bag mask ventilation and
      unexpected difficult laryngoscopy/intubation.

      Difficult laryngoscopy was defined as the Cormack-Lehane laryngoscopic view grade 3 or 4.
      Difficult intubation was defined as the occurrence of at least two of the following: 1) at
      least three intubation attempts using a conventional laryngoscope blade, either Miller or
      Macintosh; 2) intubation time (the summation of all attempts from applying a laryngoscope to
      the endotracheal tube that passed the vocal cords) >300 seconds; and 3) the occurrence of
      desaturation (SpO2 <95%)The intubation time was defined as the time starting from applying
      laryngoscope to presence of positive capnography wave form. In case of fail intubation, the
      intubation time started from applying laryngoscope to remove laryngoscope from children's
      mouth. The total intubation time was the combined timing of each intubation attempts
    

Intervention name(s): DBMV
Intervention type(s): Other
Intervention description(s): the occurrence of at least two following events which were requiring application of CPAP with opening airway maneuvers, requiring oropharyngeal airway, requiring two-person bag mask ventilation, unable to perform bag mask ventilation or presence of desaturation (SpO2 < 95%).
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        We recruited children aged up to 9 years, ASA physical status of 1-3, who came for general
        anesthesia with oroendotracheal tube intubation (OETT) for elective surgery at
        Songklanajarind Hospital
      
Keywords: unexpected difficult bag mask ventilation; difficult intubation; predictors; pediatric anesthesia