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.