Mask Ventilation & Fixing an Obstruction
Angela Mordecai, DNP, CRNA; Bailey Freeman, DNP, CRNA; Kristin Barkley, DNP, CRNA; and Brian Cornelius, DNP, CRNA
Quick Facts
Decision Algorithm
Preparation
Technique & Grips
Troubleshooting: Seal → Patency → Compliance
Special Populations & Situations
Complications & Prevention
Confirmation & Objective Grading
Documentation & Debrief
References
Decision Algorithm
Preparation
Technique & Grips
Troubleshooting: Seal → Patency → Compliance
Special Populations & Situations
Complications & Prevention
Confirmation & Objective Grading
Documentation & Debrief
References
Quick Facts
- Mask ventilation is both a primary oxygenation technique and a rescue technique when advanced devices fail.
- Risk for difficult mask ventilation climbs with age, male sex, obesity, facial hair, edentulism, Mallampati III–IV, snoring/OSA, limited jaw protrusion, larger neck circumference, and prior neck irradiation.
- Most failures are solvable by addressing three domains in order: seal → patency → compliance.
- Targets to remember: O₂ ~10 L/min (anesthesia circuit); APL open when awake then ~18–20 cmH₂O once apneic; deliver ~5–7 mL/kg with ≤20 cmH₂O peak pressure.
Decision Algorithm
- Start: Apply mask with O₂ flowing; choose correct size; align head-elevated sniffing when safe.
- One-hand C–E attempt (brief) → if any leak/poor chest rise, may add an oral airway.
- If no chest rise/inadequate ventilation, convert to two-hand technique with assistant squeezing the bag.
- Assess domains in this order, fixing each before moving on:
- Seal (mask fit/hand grip)
- Patency (chin lift/jaw thrust, OPA/NPA, suction, head rotation, CPAP, deepen anesthesia, consider NMB)
- Compliance (position head-up, treat bronchospasm, keep pressures ≤20, check equipment)
- Still inadequate? Insert a supraglottic airway or proceed to intubation per ASA difficult airway algorithm pathway.
Preparation
- Oxygen & APL: Turn fresh O₂ to ~10 L/min with APL open while awake. After LOC/apnea, partially close APL to ~18–20 cmH₂O to pressurize the circuit.
- Position: Head-elevated sniffing position (align external auditory meatus with sternal notch). Use shoulder/head elevation for obesity. Consider 10–20° head-up (reverse-Trendelenburg).
- Adjuncts ready: OPA/NPA (correct size), suction on and within reach, backup supraglottic airway available, difficult-airway plan briefed.
Technique & Grips
Breath Delivery Targets
- Slow 1-second inflations, ~5–7 mL/kg; keep peak pressure ≤20 cmH₂O to reduce gastric insufflation.
- Feel the bag refill on exhalation; avoid “hip squeeze.”
One-hand C–E (for straightforward cases)
- Thumb–index create a “C” to control the seal; ring–little fingers lift the mandible forming the “E.”
- Goal is to bring the face to the mask by lifting the mandible; avoid pressing the mask down onto soft tissue.
Two-hand Techniques (preferred with any difficulty)
- Thenar-eminence “clamp/vice” grip: All fingers under the angles of the mandible to perform strong jaw thrust; thenars/thumbs press mask for seal. Fine-tune by wrist ab/adduction.
- Bilateral C–E / Modified VE / Transverse mandibular: Variants that combine seal control with robust jaw thrust; choose the one you can sustain without fatigue.
Special Sealing Tactics
- Edentulous: Leave dentures in if safe; pack buccal spaces with gauze; place lower mask rim at lower-lip area; pull excess cheek tissue into your palms.
- Beard: Shave if time-critical; otherwise use occlusive film/dressing, saline-soaked gauze, or a small amount of gel lubricant to mat hair (note: can make the mask slippery).
- Head rotation: If persistent obstruction, a ~45° rotation may improve patency.
Troubleshooting: Seal → Patency → Compliance
Work the problem deliberately in this order. Most cases resolve before you reach step 3.
1) Seal Problems
- Clues: Collapsing bag, audible leak, poor chest rise, capnogram unstable or absent despite “easy” squeeze.
- Fixes: Recenter mask; select a better size; switch to two-hand grip; adjust wrist angle; apply edentulous/beard strategies; increase flows; remove external devices causing leak (e.g., nasogastric tube taped across cheek).
2) Patency Problems
- Clues: High delivered pressure with small Vt, thoracoabdominal “seesaw,” snoring/stridor, visible tongue collapse, soiled airway.
- Fixes:
- Open the airway: Chin lift → strong jaw thrust (two-hand), head rotation if helpful.
- Adjuncts: Insert OPA (size: incisors to angle of mandible) and/or add NPA
- Suction: Clear blood/vomit/secretions early and often.
- CPAP: Gentle continuous pressure can splint open the upper airway.
- Depth & NMB: Deepen anesthesia if “light.” Consider neuromuscular blockade to reduce pharyngeal collapse and chest wall rigidity; avoid paralysis in rare cases where diaphragmatic tone prevents large-airway collapse (e.g., tracheomalacia/mediastinal compression).
3) Compliance/Resistance Problems
- Clues: Obesity, bronchospasm (high pressures with wheeze), low lung compliance, gastric insufflation, circuit valve issues. Bag remains inflated but chest doesn’t move → think obstruction rather than leak.
- Fixes: Head-up to unload diaphragm; treat bronchospasm; keep pressures ≤20 cmH₂O; check circuit, valves, and APL setting; consider early supraglottic airway to bypass upper-airway factors.
Special Populations & Situations
- Obesity: Head-elevated position; early two-hand technique; consider CPAP; anticipate higher closing pressures; use larger NPA if needed.
- Pregnancy: Rapid desaturation; gentle MV between induction and intubation; left uterine displacement; avoid excessive pressure.
- Pediatrics: Larger tongue, cephalad larynx; use shoulder roll for neutral position. In infants with micrognathia, use two-person double C–E with jaw thrust; match rates to age if bagging.
- Edentulous/Bearded: Apply the sealing tactics above; anticipate need for early SAD if seal remains marginal.
- C-spine concerns: Favor jaw thrust and manual in-line stabilization; remove anterior collar portion if necessary to allow jaw thrust while protecting spine.
Complications & Prevention
- Gastric insufflation/aspiration: Keep pressures ≤20 cmH₂O; use adjuncts and positioning to lower required pressures.
- Tissue/dental/ocular injury: Keep fingers on bone, protect eyes, avoid prolonged focal mask pressure; mind loose teeth.
- Over-ventilation: Avoid rapid, large tidal volumes; aim 5–7 mL/kg with ~1-second inspiratory time.
- Equipment failure: If using a self-inflating bag, recognize valve malfunctions; with anesthesia circuits, verify APL/valves and leaks.
Confirmation & Objective Grading
- Capnography whenever ventilating: sustained ETCO₂ waveform confirms effective ventilation.
- Grading options you can document:
- Capnography-based A–D description (A = plateau; D = no ETCO₂).
- Descriptive ease scale (easy/awkward/difficult/impossible).
- Numerical difficulty scores (based on adjuncts used, pressures, Vt, number of operators).
- Clinical signs: Chest rise, bilateral breath sounds, fogging in circuit, SpO₂ trend, and “feel” of the collapsible bag.
Documentation & Debrief
- Note difficulty grade, techniques used (grip, adjuncts, two-person), settings (flows/APL), pressures/volumes if available, and response.
- Record patient factors (beard, edentulism, Mallampati, BMI, ROM, snoring/OSA) and complications (suspected gastric insufflation, eye/dental injury).
- Debrief what fixed the problem (e.g., head-up + OPA + clamp grip) to guide future anesthetics.
References
- Bradley WPL, Lyons C. Facemask ventilation. BJA Education. 2022;22(1):5–11.
- Baker P. Mask ventilation. F1000Res. 2018;7:F1000 Faculty Rev-1580. PMCID: PMC6206602.
- Yildiz TS, Solak M, Toker K. Incidence and risk factors of difficult mask ventilation. Can J Anesth. 2005;52(8):873–879.
- Avva U, Lata JM, Hendrix JM, Kiel J. Airway Management. StatPearls. Updated Jan 19, 2025.
- Simulation Two handout (program educational material): Airway evaluation, mask ventilation, and intubation.