Ventilator Modes & Control
In this mode, rate, ventilatory pattern, and PaCO2 are controlled, eliminating work of breathing only if the patient makes no efforts. Name the mode and one key disadvantage.
What is Controlled Mechanical Ventilation (CMV/continuous mandatory ventilation)? Disadvantage: poorly tolerated; patient efforts cause asynchrony and ↑ work of breathing; may require heavy sedation/paralysis.
List two likely causes of a persistent high-pressure alarm and the first bedside action to stabilize the patient.
Causes: mucus plug, biting ETT, kinked tubing, water in circuit. First action: assess patient and provide manual ventilation (bag) if unstable while calling RT.
Why should FiO2 be kept as low as possible, particularly when exceeding 60%?
To reduce oxygen toxicity risk; >60% FiO2 increases toxicity risk.
How does prone positioning redistribute ventilation to improve oxygenation in ARDS?
Proning improves dorsal alveolar recruitment and more even VT distribution by decreasing chest wall compliance anteriorly and mobilizing secretions.
When escalating ventilatory support, which interprofessional partner should be called immediately, and what should you do for the patient while waiting?
Respiratory therapy; bag the patient while waiting and assess.
A patient on A/C begins initiating frequent spontaneous breaths. Describe one risk and one strategy to reduce patient–ventilator asynchrony.
patient–ventilator asynchrony/dyssynchrony and ↑ work of breathing. Strategy: adjust trigger/sensitivity, ensure adequate sedation, consider mode/backup rate adjustments.
Low minute volume alarm triggers. Give two likely causes and your immediate safety step before troubleshooting the ventilator.
Causes: apnea on CPAP, circuit disconnection. Immediate step: bag the patient and call RT before troubleshooting.
Name two core elements of pulmonary hygiene/infection prevention to reduce VAP risk in ventilated patients.
Hand hygiene and diligent mouth care; also HOB elevation, infection prevention for lines and Foley, pulmonary hygiene.
List two contraindications to proning and one team-based logistical concern that must be planned for in advance.
Contraindications: hemodynamic instability, dysrhythmias, recent thoracic/abdominal surgery. Team concern: access to lines/drains and ability to handle emergencies/communication.
During high-pressure alarms that cannot be rapidly corrected, what is the manual ventilation approach and why is it prioritized?
Manual bagging with 100% oxygen; prioritizes oxygenation/ventilation when the ventilator is unsafe/unresolved.
IMV is added to modern ventilators for what primary purpose, and how does it change patient workload compared to CMV?
What is IMV to allow spontaneous breaths between mandatory breaths, reducing total ventilator workload but increasing patient work compared with CMV?
A high-pressure alarm occurs in a biting, agitated patient. Identify the immediate airway-protective device and explain how it prevents further tube damage.
What is a bite block (or oral airway)? It prevents occluding/compressing the ETT and tube damage from teeth.
If PaCO2 is trending high and tidal volume should be maintained, which ventilator change is most appropriate, and why?
Increase respiratory rate to lower PaCO2 while keeping VT constant.
State the hemodynamic effect of PEEP on venous return and the downstream impact on CO and BP.
PEEP increases intrathoracic pressure, decreasing venous return, which can reduce CO and systemic BP.
Describe how PEEP can precipitate hypotension and the initial fluid strategy to counter this while avoiding pulmonary edema.
PEEP may cause hypotension via ↓ venous return; initiate cautious fluid bolus if indicated while reassessing lungs to avoid edema.
You need to prioritize PaCO2 control without allowing variable tidal volumes. Which mode type best fits this goal, and why?
A fully controlled mandatory mode (e.g., CMV within A/C framework) because it fixes rate and tidal volume to tightly control PaCO2.
Your circuit has visible water condensation and rising peak pressures. Explain the mechanism for the alarm and the fix.
Condensation increases resistance/occlusion in circuit causing high pressures; drain water/clear circuit safely.
Mouth care frequency to prevent VAP per your slides—and the rationale.
Mouth care every 2 hours; rationale: reduces oral bacterial load and VAP risk.
Explain why both over-resuscitation and under-resuscitation are harmful in ARDS, and name one monitoring metric used to balance fluids.
Too much fluid worsens pulmonary edema; too little fluid reduces perfusion and risks MODS. Monitor hemodynamics and hourly urine output.
In an ARDS patient with rising PEEP needs and falling urine output, what two assessments guide next steps?
Hemodynamic monitoring (MAP, CV signs) and hourly urine output to assess perfusion/volume status.
Heavy sedation or neuromuscular blockade may be required in which mode and for what specific physiologic reason related to asynchrony?
CMV/mandatory ventilation; rationale: prevents patient efforts that cause asynchrony when the ventilator is fully controlling rate/VT, necessitating deep sedation/NMB to eliminate effort.
Differentiate how decreased compliance vs increased resistance will present in alarms/pressures and name one bedside clue for each.
Decreased compliance: higher peak and plateau pressures; stiff lungs; clues include ARDS, bilateral infiltrates. Increased resistance: high peak with near-normal plateau; clues include bronchospasm, kinks, secretions, biting.
Provide a stepwise strategy to reduce FiO2 while maintaining oxygenation, naming the non-FiO2 setting you would adjust first and why.
Increase PEEP to improve alveolar recruitment and oxygenation, allowing FiO2 down-titration while maintaining SpO2/PaO2.
Outline the coordinated team steps to prone a critically ill patient safely, including emergency access considerations.
Pre-brief roles; secure airway/lines; protect pressure points/eyes; coordinate turn; confirm ETT placement/vent settings post-turn; ensure access to drains/wounds; plan for emergent supination.
Provide a brief algorithm for alarm response that prioritizes patient safety, team activation, and systematic troubleshooting.
Algorithm: 1) Assess patient first (airway, breathing, SpO2). 2) If unstable, disconnect and bag; call RT. 3) Check circuit: connections, water, kinks. 4) Check airway: bite block, suction for mucus plug. 5) Reassess compliance vs resistance patterns. 6) Restore safe ventilation and document.