1.INTRODUCTION AND AIM
Providing effective ventilation of the unconscious patient during either
resuscitation or general anesthesia induction and wake-up period is an
essential skill in every specialty dealing with airway management.
Adequate mask ventilation has become an important focus in the difficult
airway algorithms’ various stages 1,2.
Determining risk factors for difficult mask ventilation (DMV)3 and providing preoxygenation 4before induction of anesthesia considering the possibility of DMV have
utmost importance in operation theaters, emergency and intensive care
units (ICU) 5.
Classic Face mask (CFM) ventilation is frequently applied also during
non-operating room anesthesia, in or out-of hospital cardiac arrests
etc. by auxiliary medical personnel and specialists not as familiar as
anesthesiologists 6.
It is emphasized that healthcare workers responsible for airway
management should be familiar with different devices and techniques that
may have advantages in certain situations 7.
Although mask ventilation is life-saving and important, this topic has
been given little coverage in the widespread scientific literature and
book chapters on airway management 8.
An important cause of difficult mask ventilation is gas leakage from
improper seal besides resistance of the airway to the gas inlet or
outlet 9.
Improper seal between the CFM and the patient’s face may occur because
of beard, facial anatomical deformity, toothlessness and etc.
Additionally facemasks somewhat increases dead space and may cause
insufficiency of tidal volume 10.
Practitioners commonly grasp the CFM with the thumb and index fingers in
the form of C and place the CFM on the face of the patient , while
raising the mandible with the other fingers in the form of E letter
although there are some alternative grips 11 (Figure
1).
Intraoral mask (IOM) is an alternative mask which is placed in the mouth
between the lips and teeth like a snorkel. Practitioners close the nose
with the tips of the thumb and index finger then with other finger grasp
and raise the mandible and close the mouth. IOM may have advantages in
situations as improper seal with the CFM. IOM also may have some
advantages for preoxygenization and can be used for non-invasive
ventilation 12-18 (Figure 2).
In this randomized observer blinded cross-over study we compared the IOM
and CFM (AMS) in terms of the effectiveness of ventilation and
practitioners’ anxiety/workload evaluation related to the masks.
Secondly we aimed to investigate the factors likely to cause and
incidence of DMV for two masks.