Vent IQ
Comprehensive mechanical ventilation education for ICU nurses — vent modes, ABG interpretation, alarm management, weaning protocols, and VAP prevention.
| Parameter | Target | Rationale |
|---|---|---|
| Tidal Volume | 4–8 mL/kg IBW (6 mL/kg preferred in ARDS) | Prevents volutrauma |
| Plateau Pressure | ≤ 30 cmH₂O | Reduces barotrauma |
| Driving Pressure | ≤ 15 cmH₂O | Strongest mortality predictor in ARDS |
| PEEP | 5–20 cmH₂O (ARDSNet table) | Prevents atelectrauma |
| SpO₂ | 88–95% (conservative in ARDS) | Avoids hyperoxia toxicity |
| pH | 7.30–7.45 (permissive hypercapnia acceptable) | Allows lung protection priority |
Education Modules
Select a topic to explore ventilation concepts, physiology, clinical application, and nursing considerations.
ABG Interpreter
Systematic acid-base and oxygenation analysis with compensation assessment.
Step 1 — pH: Acidemic or Alkalemic?
pH <7.35 = acidemia | pH >7.45 = alkalemia | 7.35–7.45 = normal (may still have disorder)
Step 2 — Primary Disorder
Respiratory: PaCO₂ >45 = respiratory acidosis; <35 = respiratory alkalosis. Metabolic: HCO₃ <22 = metabolic acidosis; >26 = metabolic alkalosis.
Step 3 — Compensation
Metabolic acidosis: expected PaCO₂ = 1.5×HCO₃ + 8 (±2) — Winter's formula
Respiratory acidosis (acute): HCO₃ rises 1 per 10↑PaCO₂
Respiratory acidosis (chronic): HCO₃ rises 3.5 per 10↑PaCO₂
Step 4 — Oxygenation
PaO₂/FiO₂ ratio: >300 normal | 200–300 mild ARDS | 100–200 moderate ARDS | <100 severe ARDS
Ventilator Modes
Mechanism, indications, settings, and nursing considerations for each mode. Tap to expand.
Calculators
Evidence-based ventilator and respiratory calculations for bedside use.
Alarm Management
Common ventilator alarms, probable causes, and immediate nursing actions.
Weaning Protocol
Evidence-based daily spontaneous awakening trial (SAT) and spontaneous breathing trial (SBT) protocol.
| Criterion | SAT Safety Screen | SBT Safety Screen |
|---|---|---|
| Sedation / agitation | No active agitation, RASS ≤ +1 | Arousable, follows commands |
| Respiratory drive | Not required | RR < 35, no significant WOB |
| FiO₂ / PEEP | Not required | FiO₂ ≤ 50%, PEEP ≤ 8 cmH₂O |
| Hemodynamics | No active MI/seizure/↑ICP | No vasopressors or low-dose; MAP > 65 |
| Secretions | No excessive secretions | Able to cough; suction ≤ q2h |
| Neuromuscular blockade | Not receiving NMBA | No residual NMBA |
Morning SAT Trial
Hold all sedation and analgesics (unless contraindicated). Monitor for agitation (RASS >+2 for >5 min), respiratory distress, SpO₂ <88%, arrhythmia, or pain. Restart sedation at 50% dose if SAT fails.
SBT Safety Screen
Once patient is alert after SAT, apply SBT safety screen (table above). If criteria met, proceed. If not met, optimize and screen again next morning.
Conduct the SBT
Place on T-piece, CPAP 5 cmH₂O, or low-level PSV (≤5–8 cmH₂O) for 30–120 minutes. Monitor continuously. Document RR, SpO₂, HR, BP, mental status, and work of breathing throughout.
Assess SBT Tolerance
PASS: RR < 35, SpO₂ ≥ 88%, no significant accessory muscle use, no diaphoresis, no hemodynamic instability, no agitation after 30+ min. Notify provider for extubation assessment.
Pre-Extubation Assessment
Adequate cough and secretion management. Upper airway assessment (cuff leak test if appropriate). Mental status adequate to protect airway. Extubation equipment, suction, and post-extubation plan ready.
SBT Failure — Return to Support
If SBT fails, return to comfortable vent settings. Investigate cause (secretions, secretion clearance, fluid overload, cardiac dysfunction, diaphragmatic weakness). Restart sedation if needed. Repeat SAT/SBT next morning.
| Parameter | Failure Threshold |
|---|---|
| Respiratory rate | >35 breaths/min for >5 min |
| SpO₂ | <88% (or <90% per institutional policy) |
| Heart rate | >20% change from baseline or >140 bpm |
| Blood pressure | SBP <90 or >180 mmHg |
| Agitation/anxiety | Marked, sustained, unresponsive to reassurance |
| Diaphoresis | Significant, unexplained |
| Accessory muscle use | Marked paradoxical breathing or retractions |
| Mental status | Acute deterioration |
VAP Prevention Bundle
Evidence-based interventions to prevent ventilator-associated pneumonia in intubated ICU patients.
Head-of-Bed Elevation 30–45°
Continuous semi-recumbent positioning prevents microaspiration of subglottic secretions. Document HOB angle every 4 hours. Contraindications: hemodynamic instability, prone positioning, spinal precautions.
Daily SAT + SBT Readiness Screen
Every day of ventilation the patient does not need the vent is a day without VAP risk. Daily weaning assessment is both a weaning strategy and VAP prevention. Document pass/fail criteria.
Oral Care with Chlorhexidine
0.12% chlorhexidine gluconate oral rinse every 6–12 hours. Brush teeth every 12 hours. Suction oropharynx before oral care. Reduces oropharyngeal bacterial burden and aspiration risk. Document time and patient tolerance.
ETT Cuff Pressure Maintenance
Maintain ETT cuff pressure at 20–30 cmH₂O (ideally 25 cmH₂O). Check every shift and after repositioning or any airway manipulation. Inadequate cuff pressure allows microaspiration around the cuff.
Subglottic Secretion Drainage
Use ETTs with subglottic suction ports when available and intubation is anticipated >48–72 hours. Perform subglottic suctioning every 1–2 hours or as per unit protocol. Reduces early-onset VAP significantly.
Stress Ulcer Prophylaxis
Administer per protocol (PPI or H₂-blocker) to prevent GI bleeding. Maintain enteral nutrition when possible — provides mucosal protection and reduces bacterial overgrowth. Review indication daily; discontinue when no longer needed.
DVT Prophylaxis
Pharmacologic (LMWH or UFH) unless contraindicated; mechanical prophylaxis (SCDs) for all patients. Reduces PE risk and complications contributing to prolonged ventilation.
Hand Hygiene
Perform hand hygiene before and after all ETT/ventilator contact. Use gloves for suctioning; sterile technique for open suctioning. Ventilator circuits: change only when visibly soiled or malfunctioning (not on schedule).
VAP is diagnosed when a patient ventilated >48 hours develops new or worsening chest X-ray infiltrate plus ≥2 of:
- Fever >38.3°C or hypothermia <36°C
- Leukocytosis (>12,000) or leukopenia (<4,000)
- New purulent secretions or change in character
- Worsening oxygenation (↑FiO₂ or PEEP requirement)
Vent IQ Quiz
25-question comprehensive assessment covering vent modes, ABG interpretation, alarm response, and weaning.
25 questions covering all Vent IQ topics. Get immediate feedback with clinical rationale on each answer.
References
Evidence base for clinical content in Vent IQ.
Guidelines & Protocols
- ARDSNet Investigators. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. N Engl J Med. 2000;342(18):1301–1308.
- Fan E, et al. An Official ATS/ESICM/SCCM Clinical Practice Guideline: Mechanical Ventilation in Adult Patients with ARDS. Am J Respir Crit Care Med. 2017;195(9):1253–1263.
- Girard TD, et al. Efficacy and safety of a paired sedation and ventilator weaning protocol for mechanically ventilated patients in intensive care (Awakening and Breathing Controlled trial). Lancet. 2008;371(9607):126–134.
- Ely EW, et al. Effect on the duration of mechanical ventilation of identifying patients capable of breathing spontaneously. N Engl J Med. 1996;335(25):1864–1869.
- Boles JM, et al. Weaning from mechanical ventilation. Eur Respir J. 2007;29(5):1033–1056.
VAP Prevention
- Klompas M, et al. Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals: 2022 Update. Infect Control Hosp Epidemiol. 2022;43(6):687–713.
- Kollef MH. Prevention of hospital-associated pneumonia and ventilator-associated pneumonia. Crit Care Med. 2004;32(6):1396–1405.
Acid-Base Physiology
- Adrogue HJ, Madias NE. Management of life-threatening acid-base disorders. N Engl J Med. 1998;338(1):26–34.
- Morganroth ML. Six steps to acid-base analysis: clinical applications. J Crit Illn. 1990;5(5):460–469.
Ventilator Modes
- Branson RD, Chatburn RL. Controversies in the critical care setting: should adaptive pressure control modes replace volume control ventilation? Respir Care. 2007;52(4):478–488.
- Daoud EG. Airway pressure release ventilation. Ann Thorac Med. 2007;2(4):176–179.
- Chatburn RL, Mireles-Cabodevila E. Closed-loop control of mechanical ventilation: description and classification of targeting schemes. Respir Care. 2011;56(1):85–98.
Oxygenation & ARDS
- Guérin C, et al. Prone positioning in severe acute respiratory distress syndrome. N Engl J Med. 2013;368(23):2159–2168.
- Papazian L, et al. Neuromuscular blockers in early acute respiratory distress syndrome. N Engl J Med. 2010;363(12):1107–1116.
- ARDS Definition Task Force. Acute Respiratory Distress Syndrome: The Berlin Definition. JAMA. 2012;307(23):2526–2533.
Nursing Practice
- American Association of Critical-Care Nurses. AACN Practice Alert: Alarm Management. 2018.
- American Association of Critical-Care Nurses. AACN Practice Alert: Prevention of Aspiration in Adults. 2016.
Vent IQ is designed for educational purposes only. Clinical decisions must be made by qualified clinicians using patient-specific assessment and institutional protocols. Content is current as of 2025.
Waveform Interpreter
Annotated pressure-time, flow-time, and volume-time waveforms for normal patterns and common dyssynchrony findings. Tap a waveform to explore.
Every breath on the vent produces three simultaneous waveforms plotted against time. Reading them together tells you what the ventilator is doing, what the patient is doing, and whether they are working together.
- Pressure-Time: Airway pressure vs. time. Shape differs by mode — square top in VC, rounded peak in PC/PRVC. The area under the curve relates to mean airway pressure (MAP).
- Flow-Time: Gas flow (L/min) vs. time. Positive = inspiratory; negative = expiratory. Flow waveform is the most sensitive indicator of patient effort and dyssynchrony.
- Volume-Time: Cumulative tidal volume vs. time. Should return to baseline at end of expiration. Failure to return = incomplete exhalation (auto-PEEP risk).
Clinical Case Scenarios
Four branching patient scenarios with decision points and immediate clinical rationale. Work through each case as you would at the bedside.