Beyond basic chest PT, advanced ICU management requires the ability to interpret ECGs, understand mechanical ventilation modes, and perform high-quality CPR. This guide focuses on high-yield exam topics.
1. ECG Interpretation Basics
A physiotherapist in the ICU must recognize life-threatening arrhythmias to determine if mobilization is safe.
[Image of normal sinus rhythm ECG strip]| Rhythm | Key Features on Graph | Physio Implication |
|---|---|---|
| Normal Sinus Rhythm (NSR) | Regular Rhythm. P wave present before every QRS. Rate 60-100 bpm. | Safe to treat. |
| Atrial Fibrillation (AFib) | "Irregularly Irregular" rhythm. No distinct P waves (wavy baseline). | Common in ICU. Caution required. Check resting HR; if >110 bpm, avoid intense PT. |
| Myocardial Infarction (STEMI) | ST-Segment Elevation (Tombstone appearance). T-wave inversion (Ischemia). | CONTRAINDICATED. Stop PT immediately. Medical emergency. |
2. Mechanical Ventilation: Modes & Settings
Understanding how the ventilator assists the patient helps in weaning and rehab.
A. SIMV (Synchronized Intermittent Mandatory Ventilation)
- Mechanism: The machine delivers a set number of breaths. However, if the patient takes a spontaneous breath, the machine synchronizes with it but does not assist that extra breath fully.
- Use: Common weaning mode. Exercises respiratory muscles.
B. CPAP (Continuous Positive Airway Pressure)
- Mechanism: Provides constant positive pressure throughout inspiration and expiration. No machine breaths are given; patient breathes on their own.
- Use: Final stage of weaning. Also used in Sleep Apnea. Keeps alveoli open (Recruitment).
C. PEEP (Positive End-Expiratory Pressure)
- Definition: A small amount of pressure (usually 5-10 cmH2O) kept in the lungs after exhalation to prevent alveoli from collapsing (atelectasis).
- Important: High PEEP (>10) indicates severe lung injury (e.g., ARDS). Caution with mobilization as disconnection causes rapid de-recruitment.
3. Oxygen Therapy Devices
[Image of oxygen mask types]| Device | Flow Rate / FiO2 | Indication |
|---|---|---|
| Nasal Cannula | 1-6 Liters/min (Low Flow) | Stable patients. Comfortable, allows eating/talking. |
| Venturi Mask | Delivers precise FiO2 (e.g., 24%, 35%, 60%) | COPD Patients. Prevents CO2 retention by controlling oxygen percentage strictly. |
| Bag Valve Mask (AMBU Bag) | 100% Oxygen (Manual) | Cardiac Arrest / Respiratory Failure. Used for manual ventilation during CPR or suctioning. |
4. CPR Guidelines (Latest AHA)
The American Heart Association (AHA) updates are critical for exams. The current sequence is C-A-B (Compression - Airway - Breathing).
Adult Basic Life Support (BLS) Summary
- Ratio: 30:2 (30 Compressions : 2 Breaths).
- Rate: 100 to 120 compressions/minute.
- Depth: At least 2 inches (5 cm) but not more than 2.4 inches (6 cm).
- Recoil: Allow full chest recoil after each compression.
- Interruption: Minimize interruptions (< 10 seconds).
Frequently Asked Questions (FAQs)
The Venturi Mask is preferred because COPD patients rely on a "Hypoxic Drive" to breathe. Giving uncontrolled high oxygen (via simple face mask) can depress their breathing. Venturi allows precise low-concentration delivery.
T-wave Inversion or ST-segment depression usually indicates ischemia (lack of oxygen). ST Elevation indicates Infarction (Tissue death).
PEEP keeps the airways popped open at the end of exhalation. This increases the Functional Residual Capacity (FRC) and improves oxygenation.
Exam Quiz: ICU & Cardio (10 MCQs)
Test your knowledge. Click the correct option to see the answer and reasoning.
1. Which ECG finding is characteristic of an acute ST-Elevation Myocardial Infarction (STEMI)?
ST-segment elevation indicates full-thickness damage to the heart muscle and is a medical emergency requiring immediate intervention.
2. In Atrial Fibrillation (AFib), the rhythm is described as:
AFib is characterized by chaotic electrical activity in the atria, leading to an "Irregularly irregular" ventricular response and absent P waves.
3. What is the recommended compression-to-breath ratio for adult CPR (single rescuer)?
AHA guidelines recommend 30 compressions followed by 2 breaths for adults to ensure adequate circulation and oxygenation.
4. Which ventilator mode allows the patient to breathe spontaneously but does NOT provide a set number of machine breaths?
CPAP provides pressure to keep airways open but relies entirely on the patient's own respiratory drive for the rate and depth of breathing.
5. Which oxygen device allows for the most precise delivery of FiO2 (Fraction of Inspired Oxygen)?
Venturi masks use adapters (color-coded) to mix oxygen with room air, delivering a fixed and precise percentage of oxygen, ideal for COPD.
6. The recommended depth of chest compressions in adult CPR is:
Compressions must be deep enough (at least 2 inches) to squeeze the heart against the spine and generate blood flow, but not too deep (>2.4 inches) to cause injury.
7. High PEEP (Positive End-Expiratory Pressure) is primarily used to prevent:
PEEP keeps alveoli open at the end of expiration, improving gas exchange and preventing atelectasis.
8. What is the recommended rate of chest compressions per minute?
A rate of 100-120 bpm is optimal. Too slow reduces flow; too fast prevents the heart from refilling with blood between compressions.
9. A Bag Valve Mask (Ambu Bag) attached to an oxygen source typically delivers how much oxygen?
When connected to a reservoir bag and high-flow oxygen source (15 L/min), an BVM delivers nearly 100% oxygen during resuscitation.
10. During SIMV mode, if a patient takes a spontaneous breath:
In SIMV, mandatory breaths are fully assisted, but spontaneous breaths between them are largely determined by the patient's own strength (though often with some pressure support).
References
- American Heart Association (AHA). (2020). Guidelines for CPR and ECC.
- Main, E., & Denehy, L. (2016). Cardiorespiratory Physiotherapy: Adults and Paediatrics. Elsevier.
- Hampton, J. R. (2013). The ECG Made Easy. Churchill Livingstone.
No comments:
Post a Comment