Bag-mask ventilation and the power of preoxygenation Crystal Lam, MS 4 John A. Burns School of Medicine Oct. 4, 2015

Bag mask ventilation In non-emergency situations, provides adequate ventilation and oxygenation to give the clinician time to pursue a controlled and well-planned approach to definitive airway management, such as endotracheal intubation

Preoxygenation 100% oxygen before induction of anesthesia is standard practice Delays onset of arterial hypoxemia during apnea (time to desaturation)

Depends on three things Patent airway – Use airway maneuvers and adjuncts Adequate mask seal Proper ventilation

1. Patent airway Head tilt, chin lift Jaw thrust maneuver Oropharyngeal airway Nasopharyngeal airway

2. Mask placement Cover: – Bridge of the nose – 2 malar eminences – Mandibular alveolar ridge Single-handed Two handed Problems with seal - troubleshooting – Facial hair – may need KY jelly or removal – False teeth reinsertion or cheeks expanded with gauze – Lower lip placement, lower end of mask positioned between lower lip and alveolar ridge reduce median air leak by 95% – Improper mask size

3. Proper ventilation Tidal volume – 8-10cc/kg – Excess TV might increase pressure  open gasroesophageal sphincter  risk of aspiration Respiratory rate Squeeze bag steadily over one full second – Do not squeeze explosively May utilize cricoid pressure

Methods 3 mins of tidal breathing 8 deep breaths within 60s

Other methods… 3 breaths in 60s? – Inferior in time for Hb to desaturate to arterial oxygen saturation (95%) – PaO2 was lower at the end compared to other methods

Plausible causes Differences in oxygen carriage by blood – Respiratory alkalosis induced by 8 breaths in 60s might increase oxygen carriage by blood Interaction of preoxygenation methods with cardiac output

Difficult mask ventilation 5% of cases 2/5 criteria increase risk of difficult intubation – Age older than 55 – BMI > 26 – Lack of teeth – Beard – h/o snoring Helps predict the risk of difficult airway  better management, to decrease morbidity and mortality from failed ventilation Next, airway management…

References Langeron, O., Masso, E., Huraux, C., Guggiari, M.,Bianchi, A., Coriat, P., Riou, B. (2000). Prediction of Difficult mask ventilation. Anesthesiology, 92: Pandit, J. J., Phil, D., Duncan, T., Robbins, P.A. (2003). Total Oxygen Uptake with Two Maximal Breathing Techniques and the Tidal Volume Breathing Technique: A Physiologic Study of Preoxygenation. Anesthesioogy, 99: Wittels, Kathleen (2015). Basic airway management in adults. Up to date. management-in- adults?source=machineLearning&search=mask+ventilation &selectedTitle=1~150&sectionRank=1&anchor=H12#H12 management-in- adults?source=machineLearning&search=mask+ventilation &selectedTitle=1~150&sectionRank=1&anchor=H12#H12

Thank you for your time and attention!