Every disease process demands a different ventilation strategy. Select a condition to see its pathophysiology, goals, recommended settings and the mistakes that cause harm.
Stiff Lungs — Low Compliance + Shunt
Low compliance with intrapulmonary shunt. The lung is stiff, and the units that are ventilated are not perfused — so oxygenation fails while the small volume of lung that remains open is easily over-distended.
ARDS is a syndrome rather than a single disease — it is the lung's final common response to a direct insult (pneumonia, aspiration, pulmonary contusion, smoke inhalation) or an indirect one (sepsis, major trauma, pancreatitis, massive transfusion). Sepsis and pneumonia account for most cases. Onset is typically 6–72 hours after the trigger, which is why a septic patient who looks well at 6 a.m. can be in respiratory failure by the afternoon.
Injury to the alveolar-capillary membrane lets protein-rich fluid leak into the airspaces, so the alveoli fill with edema and collapse. Surfactant is diluted and destroyed, and what lung remains is stiff and heterogeneous — some units over-distended, others collapsed and consolidated. Blood keeps perfusing the flooded units without picking up oxygen (shunt), which is why turning the FiO2 up barely moves the saturation and why recruitment, not oxygen, is the answer.
Mode: A/C-VC; pressure control if plateau pressure limits the volume
PEEP titration by FiO2
| FiO2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | 1.0 |
|---|---|---|---|---|---|---|---|---|
| Lower PEEP | 5 | 5–8 | 8–10 | 10 | 10–14 | 14 | 14–18 | 18–24 |
| Higher PEEP | 5–14 | 14–16 | 16–20 | 20 | 20 | 22 | 22 | 22–24 |
Monitoring the relationship between these two values is critical for a quick diagnosis:
| Scenario | PIP | Pplat | Pta (PIP − Pplat) | Primary issue |
|---|---|---|---|---|
| Tension pneumothorax | ↑ | ↑ | Normal < 5 cmH₂O | Compliance problem (lung / chest stiffness) |
| “Pipe” issues — mucus, tube kink, restricted airways | ↑ | Normal | ↑ > 5 cmH₂O | Resistance (airway blockage) |
Clinical note: If you see high airway pressures combined with sudden hypotension and a shifted trachea, this suggests a tension pneumothorax requiring immediate needle decompression.
The physiology in these cards is drawn from the sources below. Start with the mechanism if a strategy is not yet making sense — Rhesus Medicine and Ninja Nerd for the pathophysiology, EMCrit and PulmCrit for the critical care, FOAMfrat and The Resus Room for how it works on the road.
Every IBCC chapter in one list — the fastest route to the physiology behind any of these cases.
Why the pressure that actually distends the lung predicts mortality better than tidal volume alone.
An opinionated read of what neuromuscular blockade does and does not buy you in a stiff lung.
The evidence for low tidal volumes, walked through for the emergency department rather than the ICU.
Why lung protection starts on the first breath you deliver, not once the patient reaches a bed upstairs.
Type 1 and type 2 respiratory failure, modes and how to optimise a patient's own breathing before tubing them. The free episode, not the members' course page.
One page that separates a resistance problem from a compliance problem using PIP and Pplat.
Definition, pathophysiology and the whole treatment ladder on a single sheet.
When to use NIV, when not to, which interface and which mode — the decision the COPD and edema cases turn on.
How to read an oxygenation problem properly instead of guessing from the saturation.
Indications, insertion sites, ultrasound and the pitfalls — the procedure the tension case grades you on.
COPD, asthma and the rest of the respiratory conditions drawn out plainly, for when the mechanism is the gap.
Weight-based pediatric dosing, equipment sizing and ventilation rates — the reference behind the pediatric targets.
When a mechanism is easier to see than to read, watch it — each one opens on YouTube at the video itself.
Pathophysiology, causes and ventilator management — including ventilator-induced lung injury.
Taking control of the ventilator instead of chasing its numbers.
Pressure, PEEP and the patient who will not oxygenate.