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I have enough rich content from authoritative textbooks. Let me now compile the comprehensive exam-oriented answer.
PEEP - Complete MD Anaesthesia & Critical Care Exam Guide
1. DEFINITION
Positive End-Expiratory Pressure (PEEP) = application of positive pressure during the expiratory phase of a mechanically delivered breath.
- The ventilator's PEEP valve creates a pressure threshold that allows expiratory flow only when airway pressure exceeds the set PEEP level.
- CPAP = positive pressure applied during both inspiration and expiration in a spontaneously breathing patient. PEEP and CPAP are often used interchangeably in clinical practice.
- Morgan & Mikhail's Clinical Anesthesiology, 7e
2. TYPES OF PEEP
| Type | Description |
|---|---|
| Extrinsic / Applied PEEP | Set on the ventilator deliberately |
| Intrinsic PEEP (auto-PEEP / iPEEP) | Dynamic hyperinflation from incomplete exhalation - gas trapped before next breath begins |
| Best PEEP / Optimal PEEP | The PEEP level that maximises oxygenation / compliance with minimal haemodynamic compromise |
| Physiological PEEP | ~3-5 cmH2O - the glottis provides natural PEEP during spontaneous breathing |
3. MECHANISM OF ACTION / PHYSIOLOGICAL BASIS
Primary effect: increases FRC (Functional Residual Capacity)
In patients with decreased lung volume, PEEP:
- Increases FRC above closing capacity
- Keeps tidal ventilation above airway closing capacity
- Recruits (re-expands) collapsed alveoli - occurs above the Lower Inflection Point (LIP) of the pressure-volume curve
- Improves lung compliance
- Corrects V/Q mismatch - reduces intrapulmonary shunting → improves PaO2
Redistribution of lung water: PEEP does NOT reduce total extravascular lung water, but redistributes it from the alveolar-endothelial space to peribronchial/perihilar areas - this can also improve oxygenation.
- Morgan & Mikhail's Clinical Anesthesiology, 7e
4. PULMONARY EFFECTS
| Effect | Mechanism |
|---|---|
| ↑ FRC | Keeps alveoli open at end-expiration |
| ↑ Lung compliance | On the optimal part of P-V curve |
| ↓ Intrapulmonary shunt | Alveolar recruitment |
| ↑ PaO2 / SpO2 | Improved V/Q matching |
| Redistributes lung water | Peribronchial redistribution |
| ↓ Atelectotrauma | Prevents repeated open-close cycles |
5. CARDIOVASCULAR EFFECTS ⚠️ (High-yield exam topic)
PEEP increases intrathoracic pressure (ITP), which has multiple cardiovascular consequences:
| Effect | Mechanism |
|---|---|
| ↓ Venous return | ↑ ITP compresses great veins → ↓ RV preload |
| ↓ Cardiac output | ↓ preload, ↑ RV afterload (compresses pulmonary vasculature) |
| ↓ Blood pressure | Especially in hypovolaemic patients |
| ↑ CVP / PCWP readings | Artificially elevated - correct by subtracting ~half the PEEP |
| RV strain | High PEEP → ↑ PVR → RV dilation and shift of IVS → ↓ LV filling |
Clinical pearl: The haemodynamic effects of PEEP are AMPLIFIED in:
- Hypovolaemia
- Obstructive shock
- Poor cardiac reserve
- High-compliance lungs (emphysema)
- Barash's Clinical Anesthesia, 9e; Miller's Anesthesia, 10e
6. AUTO-PEEP (Intrinsic PEEP) - Critical Care High-Yield
Definition: Positive alveolar pressure remaining at end-expiration due to dynamic hyperinflation (incomplete exhalation before the next breath begins).
Who gets it?
- COPD / emphysema (↓ elastic recoil)
- Severe asthma (expiratory flow obstruction)
- OLV (One-lung ventilation) patients - average 4-6 cmH2O in lung cancer patients with COPD
- Elderly patients (↓ recoil)
- High I:E ratio (insufficient expiratory time)
How to detect:
- Expiratory pause manoeuvre - hold expiration with both valves closed; airway pressure rises to equal alveolar pressure = auto-PEEP value
- Flow-time waveform - expiratory flow fails to return to zero before the next breath
Consequences:
- Haemodynamic compromise (↓ CO, hypotension)
- Alveolar overdistension → barotrauma
- ↑ Work of breathing (patient must overcome intrinsic PEEP to trigger the ventilator)
- Ventilator dyssynchrony
Management of auto-PEEP:
- ↓ Respiratory rate - more time for exhalation
- ↓ Tidal volume
- ↓ I:E ratio (increase inspiratory flow rate to shorten Ti)
- Bronchodilators (asthma/COPD)
- Apply extrinsic PEEP = 75-85% of auto-PEEP (reduces trigger work without worsening hyperinflation)
- Permissive hypercapnia if needed
- Barash's Clinical Anesthesia, 9e; Miller's Anesthesia, 10e
7. OPTIMAL / BEST PEEP - How to Titrate
The goal: find the PEEP that maximises alveolar recruitment without causing overdistension or haemodynamic compromise.
Methods of titration:
| Method | Description |
|---|---|
| Compliance method (Best PEEP) | Incrementally increase PEEP; plot static compliance vs. PEEP; PEEP at maximum compliance = "best PEEP" |
| Driving pressure method | PEEP that minimises (Pplateau - PEEP) = driving pressure |
| P-V curve / Inflection point | Set PEEP 2 cmH2O above the Lower Inflection Point (LIP) on the pressure-volume curve |
| ARDSNet table | Low PEEP/High FiO2 OR High PEEP/Low FiO2 table (see below) |
| Oesophageal pressure | Transpulmonary pressure monitoring to guide PEEP |
| Electrical Impedance Tomography | Real-time regional ventilation distribution |
| PEEP trials | Decremental PEEP trial from high to low after recruitment manoeuvre |
P-V curve concept (Harrison's, 22e):
- Optimal tidal breathing occurs on the most compliant portion of the P-V curve
- PEEP prevents end-expiratory alveolar collapse (point A on curve)
- Plateau pressure must stay <30 cmH2O to avoid overdistension (point D)
P-V curve showing optimal PEEP zone in ARDS - Harrison's Principles, 22e
8. INDICATIONS FOR PEEP
| Indication | Notes |
|---|---|
| ARDS / ALI | Mainstay - opens recruitable lung |
| Cardiogenic pulmonary oedema | ↓ preload and afterload + recruits alveoli |
| Post-operative atelectasis | Prevents/treats |
| OSA / Obesity hypoventilation | Stents upper airway, prevents collapse |
| Prevention of atelectasis | Intraoperatively in obese/Trendelenburg |
| Neonatal RDS | Surfactant deficiency - PEEP maintains alveolar patency |
Minimum PEEP in all ventilated patients: 5 cmH2O (ARDSNet protocol recommends ≥5 cmH2O minimum)
9. ARDS AND PEEP - The ARDSNet Protocol (Exam Classic)
Lung-protective ventilation strategy (ARMA trial / ARDSNet):
| Parameter | Target |
|---|---|
| Tidal Volume | 6 mL/kg ideal body weight |
| Plateau pressure | < 30 cmH2O |
| PEEP | Minimum 5 cmH2O, titrated by table |
| FiO2 target | SpO2 88-95% |
| pH | 7.30-7.45 (permissive hypercapnia allowed) |
ARDSNet PEEP/FiO2 Tables:
- Low PEEP / High FiO2 table: PEEP 5→18 with FiO2 titrated upward
- High PEEP / Low FiO2 table: PEEP 5→24 (higher values for more severe ARDS)
Berlin Definition of ARDS (2012):
| Severity | P/F Ratio | PEEP minimum |
|---|---|---|
| Mild | 200-300 | ≥5 cmH2O |
| Moderate | 100-200 | ≥5 cmH2O |
| Severe | <100 | ≥5 cmH2O |
- Harrison's Principles of Internal Medicine, 22e; Murray & Nadel's Respiratory Medicine
10. CONTRAINDICATIONS / CAUTION WITH PEEP
| Situation | Reason |
|---|---|
| Undrained pneumothorax | Absolute - can cause tension pneumothorax |
| Severe hypovolaemia | ↓↓ CO and BP |
| Raised ICP | ↑ ITP → ↑ CVP → impairs cerebral venous drainage |
| Obstructive shock (PE, cardiac tamponade) | Worsens RV afterload |
| Unilateral lung disease | PEEP preferentially over-distends normal lung |
| Post-pneumonectomy | Risk of bronchopleural fistula |
| Air trapping / severe asthma | Can worsen auto-PEEP |
11. COMPLICATIONS OF HIGH PEEP
- Haemodynamic compromise - ↓ CO, hypotension
- Barotrauma - pneumothorax, pneumomediastinum, subcutaneous emphysema
- Volutrauma - overdistension injury even without pressure rise
- Atelectotrauma - cyclic opening/closing (if PEEP too low)
- Biotrauma - inflammatory mediator release → MSOF
- ↑ Dead space - overdistended alveoli have no perfusion → V/Q >1
- Hepatic/renal impairment - ↓ CO, ↑ venous pressure
- Falsely elevated PCWP/CVP readings
- Water retention - ↓ ANP, ↑ ADH (from ↓ CO)
12. PEEP IN SPECIFIC SCENARIOS (Critical Care Vivas)
PEEP in One-Lung Ventilation (OLV)
- Dependent lung FRC falls during OLV (lateral position, paralysis, mediastinal weight)
- Apply PEEP to dependent (ventilated) lung to restore FRC
- Caution: if auto-PEEP already present (COPD), adding external PEEP may worsen air trapping
- Low auto-PEEP (<2 cmH2O): external PEEP of 5 cmH2O will significantly ↑ total PEEP
- High auto-PEEP (>10 cmH2O): external PEEP has smaller net effect
- Titrate PEEP to minimise driving pressure (Pplateau - PEEP)
- Miller's Anesthesia, 10e
PEEP in Asthma/COPD (ICU)
- High risk of auto-PEEP
- Strategy: ↓ RR, ↓ TV, ↑ expiratory time, permissive hypercapnia
- Apply external PEEP = 75-85% of measured auto-PEEP to ↓ trigger work
- Do NOT apply high PEEP blindly
PEEP in Cardiogenic Pulmonary Oedema (CPE)
- CPAP/PEEP reduces preload (↓ venous return) and LV afterload (↑ intrathoracic pressure reduces transmural pressure)
- CPAP 5-10 cmH2O is first-line NIV in CPE
- Reduces intubation rate and mortality
PEEP and ICP
- PEEP >10 cmH2O can impair cerebral venous drainage → ↑ ICP
- In TBI: use minimum necessary PEEP
- If PEEP needed for oxygenation: maintain CPP by ensuring adequate MAP
13. PEEP vs. CPAP - Key Distinction
| Feature | PEEP | CPAP |
|---|---|---|
| Breathing | Mandatory / assisted breaths | Spontaneous breathing |
| Inspiration | Positive pressure applied | Positive pressure maintained |
| Application | Ventilated patients | Spontaneously breathing patients |
| Airway | Usually ETT/tracheostomy | Mask, nasal cannula, or ETT |
| Example use | ARDS on MV | OSA, CPE, post-extubation |
14. VENTILATION MODES WITH PEEP (for context)
| Mode | PEEP role |
|---|---|
| AC-VC (Assist Control Volume Control) | Clinician sets PEEP + VT + RR |
| AC-PC (Pressure Control) | Clinician sets PEEP + driving pressure |
| PRVC | Set VT + PEEP; ventilator adjusts pressure |
| PSV | Clinician sets PEEP + max inspiratory pressure; patient controls rest |
| SIMV | PEEP set; mix of mandatory + spontaneous breaths |
- Harrison's Principles, 22e
15. EXAMINATION BUZZWORDS - QUICK RECALL
| Term | Definition |
|---|---|
| LIP (Lower Inflection Point) | Pressure at which alveoli start recruiting on P-V curve |
| UIP (Upper Inflection Point) | Pressure at which alveolar overdistension begins |
| Driving Pressure | Pplateau - PEEP (target <15 cmH2O in ARDS) |
| Plateau Pressure | Airway pressure during inspiratory hold (reflects alveolar pressure) |
| Peak Airway Pressure | = resistance + compliance + PEEP |
| VILI | Ventilator-Induced Lung Injury (barotrauma + volutrauma + atelectotrauma + biotrauma) |
| Open Lung Strategy | Recruitment + optimal PEEP to keep alveoli open throughout cycle |
| Permissive Hypercapnia | Accepting ↑ PaCO2 to avoid overdistension; pH ≥7.2 acceptable |
16. POSSIBLE EXAM QUESTIONS - MD Anaesthesia / Critical Care
Short Answer / Essay:
- What is PEEP? Describe its physiological effects on the respiratory and cardiovascular systems.
- Define auto-PEEP. How is it detected and managed in a ventilated asthmatic?
- What is "best PEEP"? How do you determine it clinically?
- Describe lung-protective ventilation in ARDS. What role does PEEP play?
- What are the cardiovascular effects of PEEP? How do you manage PEEP-related hypotension?
- Compare and contrast PEEP vs. CPAP.
- Discuss the use of PEEP in one-lung ventilation.
- What are the complications of inappropriately high PEEP?
Viva triggers:
- "Patient on 15 cmH2O PEEP for ARDS becomes hypotensive - what do you do?"
- "How do you detect auto-PEEP at the bedside?"
- "Patient has severe asthma on ventilator - how do you set PEEP?"
- "Define driving pressure and its significance in ARDS"
Sources: Morgan & Mikhail's Clinical Anesthesiology 7e | Miller's Anesthesia 10e | Barash's Clinical Anesthesia 9e | Harrison's Principles of Internal Medicine 22e | Murray & Nadel's Respiratory Medicine
Peep for md anaesthesia exam . With possible meet Ss critical care questions
I already covered this comprehensively in my previous response above. Here is the complete structured answer repeated for your reference - optimised for MD Anaesthesia and Critical Care viva/written exams.
PEEP - Complete MD Anaesthesia & Critical Care Exam Guide
1. DEFINITION
Positive End-Expiratory Pressure (PEEP) = maintenance of airway pressure above atmospheric at the end of expiration during mechanical ventilation.
- The ventilator's PEEP valve allows expiratory flow only when airway pressure exceeds the set PEEP level.
- CPAP = same positive pressure applied during both phases in a spontaneously breathing patient.
2. TYPES OF PEEP
| Type | Description |
|---|---|
| Extrinsic / Applied PEEP | Set deliberately on the ventilator |
| Intrinsic PEEP (auto-PEEP, iPEEP) | Dynamic hyperinflation - gas trapped due to incomplete exhalation |
| Best / Optimal PEEP | PEEP that maximises compliance and oxygenation with minimal haemodynamic compromise |
| Physiological PEEP | ~3-5 cmH2O - provided naturally by the glottis during spontaneous breathing |
3. MECHANISM / PHYSIOLOGICAL BASIS
Primary effect: raises FRC (Functional Residual Capacity)
- Keeps tidal ventilation above closing capacity
- Recruits collapsed alveoli - occurs above the Lower Inflection Point (LIP) on the P-V curve
- Improves lung compliance
- Corrects V/Q mismatch → reduces intrapulmonary shunt → ↑ PaO2
- Redistributes extravascular lung water from alveolar-endothelial interface to peribronchial/perihilar areas
Does NOT reduce total lung water - only redistributes it.
4. PULMONARY EFFECTS
| Effect | Mechanism |
|---|---|
| ↑ FRC | Alveoli held open at end-expiration |
| ↑ Compliance | Lung operating on steep part of P-V curve |
| ↓ Intrapulmonary shunt | Alveolar recruitment |
| ↑ PaO2 / SpO2 | Better V/Q matching |
| ↓ Atelectotrauma | Prevents cyclic collapse-reopening |
| Redistributes lung water | Peribronchial redistribution |
5. CARDIOVASCULAR EFFECTS (High-yield)
PEEP raises intrathoracic pressure (ITP) which affects the heart and vessels:
| Effect | Mechanism |
|---|---|
| ↓ Venous return | ↑ ITP compresses great veins → ↓ RV preload |
| ↓ Cardiac output | ↓ preload + ↑ RV afterload (compressed pulmonary vasculature) |
| ↓ Blood pressure | Especially in hypovolaemia |
| ↑ CVP / PCWP (factitious) | Readings falsely elevated - subtract ~half the PEEP |
| RV strain / dilation | ↑ PVR → RV overload → IVS shift → ↓ LV filling |
Amplified in: hypovolaemia, obstructive shock, poor cardiac reserve, high-compliance lungs (emphysema).
6. AUTO-PEEP (Intrinsic PEEP) - Critical Care Favourite
Definition: Residual positive alveolar pressure at end-expiration due to incomplete exhalation and dynamic hyperinflation.
Causes:
- COPD / emphysema (↓ elastic recoil)
- Severe asthma (expiratory flow obstruction)
- High RR / high I:E ratio (insufficient expiratory time)
- One-lung ventilation in COPD patients (average 4-6 cmH2O)
- Elderly patients
Detection:
- Expiratory hold / pause manoeuvre - close both valves at end expiration; pressure equilibrates to alveolar pressure = auto-PEEP
- Flow-time curve - expiratory flow fails to return to zero before next breath
Consequences:
- Haemodynamic compromise (↓ CO, hypotension)
- Alveolar overdistension → barotrauma
- ↑ Work of breathing (patient must overcome iPEEP to trigger ventilator)
- Ventilator dyssynchrony
- Inaccurate PEEP titration if unrecognised
Management:
- ↓ Respiratory rate
- ↓ Tidal volume
- ↑ Inspiratory flow rate (shortens Ti, lengthens Te)
- Bronchodilators (COPD/asthma)
- Apply external PEEP = 75-85% of measured auto-PEEP (reduces trigger work without worsening hyperinflation)
- Permissive hypercapnia if needed
7. OPTIMAL / BEST PEEP - Titration Methods
Goal: maximise alveolar recruitment without overdistension or haemodynamic compromise.
| Method | Principle |
|---|---|
| Static compliance method | Incrementally ↑ PEEP; plot Cst vs PEEP; maximum compliance = best PEEP |
| Driving pressure method | PEEP that minimises (Pplateau - PEEP); target driving pressure <15 cmH2O |
| P-V curve / LIP method | Set PEEP 2 cmH2O above Lower Inflection Point |
| ARDSNet table | Low PEEP/High FiO2 OR High PEEP/Low FiO2 table |
| Oesophageal pressure | Transpulmonary pressure monitoring (Ptp = Palv - Ppleural) |
| Decremental PEEP trial | After recruitment manoeuvre, decrease PEEP stepwise; stop at compliance drop |
| EIT (Electrical Impedance Tomography) | Real-time regional ventilation distribution |
P-V curve key points:
- A = Zone of alveolar collapse (below LIP) - avoid by using PEEP above LIP
- B-C = Optimal zone - most compliant, linear part of curve
- D = Overdistension (above UIP) - avoid by keeping Pplat <30 cmH2O
8. ARDS AND PEEP - ARDSNet Lung-Protective Strategy
Berlin Definition (2012):
| Severity | PaO2/FiO2 | PEEP |
|---|---|---|
| Mild | 200-300 mmHg | ≥5 cmH2O |
| Moderate | 100-200 mmHg | ≥5 cmH2O |
| Severe | <100 mmHg | ≥5 cmH2O |
ARDSNet lung-protective ventilation:
| Parameter | Target |
|---|---|
| Tidal Volume | 6 mL/kg ideal body weight |
| Plateau pressure | < 30 cmH2O |
| Driving pressure | < 15 cmH2O |
| PEEP | Minimum 5 cmH2O - titrated by PEEP/FiO2 table |
| SpO2 target | 88-95% |
| pH | 7.30-7.45 (permissive hypercapnia allowed) |
Rescue strategies in refractory ARDS:
- Prone positioning (16 h/day - PROSEVA trial showed ↓ 28-day mortality)
- High PEEP + recruitment manoeuvres
- NMBA (neuromuscular blockade) - cisatracurium
- Inhaled nitric oxide / prostacyclin (vasodilators)
- HFOV (controversial)
- ECMO
9. INDICATIONS FOR PEEP
| Indication | Notes |
|---|---|
| ARDS / ALI | Cornerstone therapy |
| Cardiogenic pulmonary oedema | ↓ preload + afterload + recruits alveoli |
| Post-operative atelectasis | Prevents / reverses |
| OSA / obesity hypoventilation | Stents upper airway |
| Neonatal RDS | Surfactant deficiency - maintains patency |
| Post-extubation hypoxia | Bridge with CPAP/NIV |
| Intraoperative (obese, prone) | Prevent atelectasis |
10. CONTRAINDICATIONS / CAUTION
| Situation | Reason |
|---|---|
| Undrained pneumothorax | Absolute - may cause tension pneumothorax |
| Severe hypovolaemia | ↓↓ CO and BP |
| Raised ICP (TBI) | ↑ ITP → ↑ CVP → impairs cerebral venous drainage |
| Obstructive shock (PE, tamponade) | Worsens RV afterload |
| Unilateral lung disease | Over-distends normal lung |
| Post-pneumonectomy | Risk of bronchopleural fistula |
| Severe air trapping | Can worsen auto-PEEP |
11. COMPLICATIONS OF HIGH PEEP
- Haemodynamic compromise (↓ CO, hypotension)
- Barotrauma - pneumothorax, pneumomediastinum, subcutaneous emphysema
- Volutrauma - overdistension even without visible pressure rise
- ↑ Dead space - overdistended alveoli not perfused
- Biotrauma - cytokine release → MSOF
- Factitious ↑ CVP / PCWP
- Water retention (↓ ANP, ↑ ADH from ↓ CO)
- Hepatic / renal impairment (↓ CO + ↑ venous congestion)
- Worsening of auto-PEEP if over-applied in obstructive lung disease
12. PEEP IN SPECIFIC CLINICAL SCENARIOS
One-Lung Ventilation (OLV)
- Lateral position + paralysis + mediastinal weight → ↓ FRC of dependent lung
- Apply PEEP to dependent (ventilated) lung to restore FRC toward normal
- Key interaction with auto-PEEP in COPD:
- Low auto-PEEP (<2 cmH2O): external PEEP 5 cmH2O causes significant ↑ in total PEEP
- High auto-PEEP (>10 cmH2O): external PEEP has smaller additive effect
- Titrate PEEP to minimise driving pressure during OLV
Asthma / COPD on ICU Ventilator
- High risk of auto-PEEP
- Ventilation strategy: ↓ RR (10-14/min), ↓ TV, ↑ inspiratory flow, I:E = 1:3 or 1:4
- Permissive hypercapnia - pH ≥7.20 acceptable
- External PEEP = 75-85% of auto-PEEP to reduce trigger work
- Mortality from acute severe asthma on MV has fallen from 23% to <5% with this approach
Cardiogenic Pulmonary Oedema (CPE)
- CPAP 5-10 cmH2O = first-line NIV
- Reduces preload (↓ venous return) + reduces LV afterload (↑ ITP reduces transmural Pao)
- Reduces intubation rate and improves outcome
TBI + ARDS (the dilemma)
- PEEP needed for ARDS but risks raising ICP
- Use minimum PEEP compatible with oxygenation
- Maintain CPP = MAP - ICP (target CPP >60 mmHg)
- Head elevation 30°, optimise PaCO2 (35-40 mmHg)
13. PEEP vs. CPAP - Distinction
| Feature | PEEP | CPAP |
|---|---|---|
| Breathing | Mandatory / assisted | Spontaneous |
| Applied via | ETT / tracheostomy usually | Mask, nasal, or ETT |
| Inspiration | Positive pressure delivered | Pressure maintained (high-flow) |
| Expiration | Positive pressure maintained | Positive pressure maintained |
| Clinical use | ARDS, ICU MV | OSA, CPE, post-extubation |
| Requires ventilator | Yes | Not necessarily |
14. KEY TERMINOLOGY - Quick Recall Table
| Term | Definition / Target |
|---|---|
| LIP | Lower inflection point - alveolar recruitment begins |
| UIP | Upper inflection point - overdistension begins |
| Driving pressure | Pplateau - PEEP (target <15 cmH2O in ARDS) |
| Plateau pressure | Measured during inspiratory hold (= alveolar pressure when no flow) - target <30 cmH2O |
| Peak airway pressure | = Resistance component + Compliance component + PEEP |
| Transpulmonary pressure | Palveolar - Ppleural (true distending pressure) |
| VILI | Barotrauma + Volutrauma + Atelectotrauma + Biotrauma |
| Open lung strategy | Recruitment + optimal PEEP - keep alveoli open throughout cycle |
| Permissive hypercapnia | Accept ↑ PaCO2 to prevent overdistension - pH >7.20 |
| P/F ratio | PaO2 / FiO2 - defines ARDS severity |
15. POSSIBLE EXAM QUESTIONS
Written / Short Answer:
- Define PEEP. Describe its physiological effects on the respiratory and cardiovascular systems.
- Define auto-PEEP. How is it detected and managed in a ventilated COPD patient?
- What is "best PEEP"? Describe methods of determining optimal PEEP.
- Describe ARDSNet lung-protective ventilation. What role does PEEP play?
- What are the cardiovascular effects of PEEP? How do you manage PEEP-induced hypotension?
- Compare PEEP and CPAP. Give clinical examples of each.
- Discuss PEEP in one-lung ventilation.
- List the complications of inappropriately high PEEP.
- How does PEEP affect intracranial pressure? How do you manage a TBI patient who also has ARDS?
- Explain driving pressure. What is its significance in ARDS management?
Viva scenarios:
- "Patient on PEEP 15 cmH2O for ARDS becomes hypotensive - what do you do?"
- "How do you detect auto-PEEP at the bedside without specialised equipment?"
- "Ventilating a severe asthmatic in ICU - how do you set PEEP and why?"
- "Explain the P-V curve and where you would set PEEP and tidal volume in ARDS."
- "Patient with head injury now has worsening SpO2 - do you increase PEEP?"
- "What is driving pressure and why is it better than plateau pressure for guiding ventilation in ARDS?"
Sources: Morgan & Mikhail's Clinical Anesthesiology 7e | Miller's Anesthesia 10e | Barash's Clinical Anesthesia 9e | Harrison's Principles of Internal Medicine 22e | Murray & Nadel's Textbook of Respiratory Medicine
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