A Comparison of the Face Mask and Oral Mask Ventilation After Nasal Surgery
Condition: Nasal Septum Deviation
Study type: Interventional
Phase: Phase 4

Summary: 
      Difficult mask ventilation is usually studied in relation to airway management and difficult
      intubation and mostly during the induction period of anesthesia.

      According to the closed claim reports tracheal extubation and recovery of anesthesia is
      associated with brain damage or death.

      Difficult mask ventilation can also be a problem during the emergence phase of anesthesia
      after extubation. Especially after nasal surgery the use of nasal tampon and casts can
      resemble upper airway obstruction and facial deformity and cause difficult mask ventilation.

      The effectiveness of ventilation is affected by the design of the mask. Leaks may develop due
      to the inability to obtain a tight seal.

      The use of an oral mask for ventilation in patients with nasal tumors and after rhinoplasty
      for patients with a nasal cast has been reported. This suggests that oral mask ventilation,
      rather than face mask ventilation, should be considered after nasal surgery.

      The aim of this prospective randomized study is to compare the face mask and oral mask
      ventilation after nasal surgery in terms of the mask ventilation classification, airway
      pressure, minute ventilation and tidal volume.

      Our hypothesis is that ventilation with oral mask would provide better airway pressures,
      superior mask-ventilation classification and higher tidal volumes compared to face mask
      ventilation in patients with obstructed nasal pasage (nasal packing and/or cast) after nasal
      surgery'.
    

Detailed description: 
      American Society of Anesthesiologists (ASA) physical class I or II, adult patients aging
      19-45 yr, scheduled for nasal surgery will be recruited.

      Patient characteristics will be recorded; age, gender ASA physical status, height, weight.
      Simple randomization will be accomplished with a computer-generated sequence of numbers and
      sealed envelopes will be used to allocate patients into 2 treatment sequences, Sequence O:
      oral mask ventilation followed by face mask ventilation and Sequence FM: face mask
      ventilation followed by oral mask ventilation.

      Patients will be premedicated with midazolam. Ringer's lactate infusion at 15 mL•kg-1•h-1
      will be initiated. Standard monitors will be established including neuromuscular
      monitorization and the Bispectral index monitor (BIS).

      The patients head will be placed in the neutral position on a positioning pad Anesthesia will
      be induced with propofol 2 ml kg and fentanyl 50 mcg. Anesthesia will be maintained with
      oxygen in nitrous oxide and sevoflurane. The patient was ventilated trough an face mask. The
      appropriate size mask with the best fit will be selected and the mask size will be noted. Gas
      flow will be 4 L min. During the induction period the mask ventilation grade of the patients
      will be determined (Grade 0: ventilation by mask not attempted, Grade 1: ventilated by mask,
      Grade 2: ventilated by mask with oral airway or other adjuvant, Grade 3: difficult mask
      ventilation (inadequate, unstable, or requiring two practitioners), Grade 4: unable to mask
      ventilate (Han's grading scale)) and patients with Grade ≥ 2 will be excluded from the study.
      Muscle relaxation and intubation will be facilitated with rocuronium 0.6 mg kg-1. At the end
      of surgery trachea will be extubated when TOF 0.9 is obtained and the patient is spontaneous
      breathing, meanwhile inhalation anesthesia will be continued (BIS 50-70). After extubation,
      spontaneous ventilation will be assisted with mask ventilation. Mask ventilation will be
      applied according to sequence allocation and the mask ventilation grades with each mask
      technique will be determined with the same grading system. Spontaneous ventilation will be
      assisted with mask ventilation.

      The face mask will be applied with the one handed EC-clamp technique. The mask will be placed
      over the bridge of the nose and mouth and a chin-lift, head tilt maneuver will be used. The
      oral mask; size 1 or 2 child's mask will be placed only over the mouth and the one handed
      EC-clamp technique with the chin-lift, head tilt maneuver will be used again. The masks will
      be changed after three consecutive measurements for each mask technique and the crossover
      time will be short.

      The respiratory parameters will be measured with the monitor contained in the Drager Primus
      anesthesia machine. The observer providing mask ventilation is experienced in mask
      ventilation and will be blinded to the monitor display. All patients will be ventilated by
      the same observer. Data will be recorded by independent residents. The mask ventilation
      classification will be recorded. mean airway pressure (Pmean), maximum airway pressure
      (Ppeak) , tidal volume (TV), expired tidal volume (TVe) minute volume leak (MVleak) and
      minute volume (MV) will be recorded during spontaneous ventilation. Volatile anesthesia will
      be ceased after observing that the patients are calm and not coughing and the respiratory
      measures will be evaluated thereafter. The APL (airway pressure release) valve will be closed
      during the evaluation of mask ventilation. Sufficient chest movement, mask leak, gastric
      insufflations will be assessed. Indicators for difficult mask ventilation are defined as; TV<
      4 ml kg, inadequate chest movements, the need for an oropharyngeal airway, two handed mask
      ventilation, need to increase the gas flow, gastric insufflations, need to ventilate with two
      operators.

      It was planned to enroll 30 patients in this study. After performing a pilot study we
      calculated that 10 patients in each group was sufficient to detect a difference between
      groups concerning tidal volume with 0.95 power and 0.05 alfa error. We decided to enroll 24
      patients in the study due to possible drop outs.
    

Intervention name(s): Face Mask; Oral Mask
Intervention type(s): Device; Device
Intervention description(s): Patients will be ventilated trough a face mask first and trough a oral mask thereafter; Patients will be ventilated trough an oral mask first and trough a face mask thereafter
Other intervention name(s): Adult anesthesia face mask; Rusch reusable anatomical black rubber adult face mask; Pediatric anesthesia face mask; Rusch reusable anatomical black rubber pediatric mask
Intervention MeSH terms: Anesthetics
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary purpose: Treatment
Keywords: Difficult mask ventilation; extubation; nasal surgery