CCLS (Comprehensive Cardiopulmonary Life Support) vs ACLS (Advanced Cardiovascular Life Support)

What is CCLS?

CCLS - Core Framework

The 5 Core Links

CCLS Algorithm - Key Steps

1. Assess safety of environment
2. Assess responsiveness - tap shoulders, call out
3. Call for help - activate Code Blue, get crash cart + defibrillator
4. Check breathing - look, listen, feel (≤10 seconds)
5. Start high-quality CPR: C-A-B sequence
   • Chest compressions: rate 100-120/min, depth ≥5 cm, full recoil, minimize interruptions
   • Airway: head-tilt/chin-lift or jaw thrust; use adjuncts (OPA/NPA)
   • Breathing: bag-mask ventilation 30:2 ratio until advanced airway placed
6. Defibrillate as soon as available (shockable rhythms: VF/pVT)
7. Advanced airway placement (ETT/LMA/supraglottic device) - once placed, continuous compressions + 10 breaths/min
8. Vascular access (IV/IO) and drugs: Adrenaline (epinephrine) 1 mg IV every 3-5 minutes; Amiodarone 300 mg for refractory VF/pVT
9. Identify and treat reversible causes (4H4T - Hypoxia, Hypovolaemia, Hypo/Hyperkalaemia, Hypothermia / Tension pneumothorax, Tamponade, Toxins, Thrombosis)
10. Post-resuscitation care: MAP >65 mmHg, targeted temperature management, ICU monitoring

Design Philosophy

• Simplified single unified algorithm covering BLS through ALS in one flow
• Designed for settings where the full crash cart/advanced team may take time to arrive
• Allows concurrent multitasking by a hospital team while maintaining algorithmic sequence
• Evidence base: international literature (AHA, ERC, ILCOR) adapted by Indian experts

ACLS (2025 AHA) - Updated Guidelines

Major 2025 ACLS Updates

• IV access is the first choice for drug administration in cardiac arrest
• IO (intraosseous) access is reasonable if IV attempts fail
• Establishes a clear priority sequence not explicitly stated in 2020 guidelines

• Emphasis on visible chest rise as the target for tidal volume
• Ventilation rate: 1 breath every 6 seconds (10/min) for respiratory arrest
• Trauma: jaw thrust preferred, but head-tilt/chin-lift permitted if jaw thrust fails

• Old (2020): Adults - abdominal thrusts first
• New (2025): 5 back blows → 5 abdominal thrusts (alternating cycles) for adults and children
• Infants: 5 back blows → 5 chest thrusts (unchanged)

• Higher first-shock energy (≥200 J) preferred for cardioversion of AF/atrial flutter
• End-tidal CO₂ (ETCO₂) alone should NOT be used to terminate resuscitation

• Naloxone may be reasonable in cardiac arrest with suspected opioid overdose, provided it does not interfere with standard CPR

• Hemodynamic stabilization targets refined
• Structured post-arrest recovery assessment now formally recommended: physical, cognitive, psychological, family/caregiver support

• Standard CPR technique applies - no modifications needed (supported by 2024 ILCOR review of 34 studies)

• Rules applied based on EMS scope (BLS, ALS, or universal TOR rule)
• ETCO₂ should not be used in isolation to end resuscitation

Head-to-Head Comparison: CCLS vs ACLS

Key Practical Distinctions

1. Single vs. Modular Algorithm: CCLS uses one continuous algorithm intentionally, so a hospital team member at any level can follow it start to finish. ACLS uses separate, modular algorithms for different arrest rhythms and situations.
2. Pre-arrest recognition (CCLS Link 1): CCLS explicitly makes pre-arrest recognition its first core link - this reflects an Indian context where early warning systems and rapid response teams may be less resourced. AHA 2025 also addresses this but it is not framed as a primary chain link.
3. Concurrent actions: CCLS explicitly states that while the algorithm is sequential, steps should be done simultaneously by available team members. This is a practical nod to variable team sizes.
4. Post-resuscitation: ACLS 2025 is significantly more detailed in post-cardiac arrest care (temperature management, hemodynamic targets, neurological assessment, rehabilitation planning). CCLS's MAP >65 mmHg target is a simplified version of this.
5. FBAO: 2025 ACLS now matches closer to what many other international guidelines recommend (back blows + abdominal thrusts), moving away from Heimlich-only approach.

Summary

Citation: Garg R, Ahmed SM, Kapoor MC et al. Comprehensive cardiopulmonary life support (CCLS) for cardiopulmonary resuscitation by trained paramedics and medics inside the hospital. Indian J Anaesth. 2017;61(11):857-868. PMID: 29217853

AHA Part 9: Adult Advanced Life Support: 2025 AHA Guidelines for CPR and ECC. Circulation. 2025;152(suppl 2). DOI: 10.1161/CIR.0000000000001376

Mini Fluid Challenge - Dynamic or Static?

Why It Is Dynamic - The Conceptual Framework

Static Parameters (unreliable predictors)

• Central venous pressure (CVP)
• Pulmonary capillary wedge pressure (PCWP)
• IVC diameter at rest
• End-diastolic ventricular volumes

Dynamic Parameters (superior predictors)

• Pulse pressure variation (PPV)
• Stroke volume variation (SVV)
• IVC distensibility/collapsibility index
• Passive leg raise (PLR) + CO measurement
• Mini fluid challenge + CO measurement ← this one
• End-expiratory/end-inspiratory occlusion tests
• Carotid peak velocity variation

The Mini Fluid Challenge - Specifics

"The most straightforward dynamic test of fluid responsiveness is a fluid challenge with measurement of CO before and after. Typically, a small bolus of approximately 100 to 250 mL of intravenous fluid is used."

• Miller's Anesthesia, 10e (p. 11911)

Why "Mini" Instead of a Standard Fluid Challenge (250-500 mL)?

Comparison Summary: Static vs Dynamic

Key Insight

• Miller's Anesthesia, 10e, p. 11911 (Fluid Responsiveness section)
• Miller's Anesthesia, 10e, p. 5067-5069 (Echocardiographic dynamic parameters)

Normal CVP and PCWP Values

CVP (Central Venous Pressure)

Practical standard: 2-8 mmHg (or 6-12 cm H₂O, since 1 mmHg ≈ 1.36 cm H₂O)

• < 2 mmHg → Low (hypovolaemia, vasodilation)
• 2-8 mmHg → Normal

• 8-12 mmHg → Elevated (right heart failure, fluid overload, tamponade, tension pneumothorax)

PCWP / PAWP (Pulmonary Capillary / Artery Wedge Pressure)

Practical standard: 6-12 mmHg

• < 6 mmHg → Low (hypovolaemia, RV failure)
• 6-12 mmHg → Normal
• 13-18 mmHg → Mildly elevated (volume overload)
• 18-22 mmHg → Moderately elevated, risk of pulmonary oedema

• 22 mmHg → Cardiogenic pulmonary oedema

Full PA Catheter Normal Values (for context)

Important Clinical Caveat

• Fischer's Mastery of Surgery, 8e, Table 6.5
• Tintinalli's Emergency Medicine (CVP section)
• Harrison's Principles of Internal Medicine, 22e (2025)

IVC Diameter and Fluid Responsiveness

IVC diameter alone = static parameter (a single snapshot of size) IVC collapsibility/distensibility index = dynamic parameter (measures respiratory variation)

1. Static Assessment - IVC Diameter Alone

ASE (American Society of Echocardiography) Guidelines - IVC Diameter and RAP Estimation

• IVC < 1.5 cm that collapses completely → very low RAP, almost certainly fluid responsive
• IVC > 2.5 cm with no collapse → high RAP, very unlikely to be fluid responsive

2. Dynamic Assessment - IVC Collapsibility Index (cIVC)

3. Dynamic Assessment - IVC Distensibility Index (dIVC)

Important Limitations of IVC for Fluid Responsiveness

• No spontaneous respiratory effort (for dIVC in ventilated patients)
• Tidal volume 8-12 mL/kg (low TV ventilation reduces IVC variability - unreliable with TV < 8 mL/kg)
• PEEP ≤ 5 cm H₂O (higher PEEP reduces accuracy)
• No cor pulmonale (RV dysfunction falsely elevates IVC diameter)
• No intra-abdominal hypertension (compresses IVC, gives false readings)
• Not reliable in atrial fibrillation or other arrhythmias

"Changes in IVC diameter during the respiratory cycle are not reliable indicators of RA pressure in patients on mechanical ventilation" (when using collapsibility index designed for spontaneous breathing)

• Textbook of Clinical Echocardiography

"dIVC has greater specificity than sensitivity" and "ΔIVC less accurate in more heterogeneous populations"

• Miller's Anesthesia, 10e

Summary Table

• Textbook of Clinical Echocardiography, Table 6.6
• Miller's Anesthesia, 10e, p. 5015-5016 & 5067
• Comprehensive Clinical Nephrology, 7e

Pleth Variability Index (PVI) - Dynamic or Static?

"The Pleth Variability Index (PVI), a dynamic and non-invasive indicator of fluid responsiveness..."

What is PVI? - The Mechanism

PVI Threshold for Fluid Responsiveness

How PVI Compares to Other Dynamic Parameters

Clinical Performance and Limitations

• Truly non-invasive - no arterial line needed
• Continuous, real-time, automated display (Masimo Radical-7)
• Goal-directed PVI-guided therapy significantly reduces total intraoperative fluid volume (-761 mL vs conventional management) without compromising haemodynamics
• Reduces crystalloid use (-655 mL) without worsening urine output or acid-base balance
• Shown to improve outcomes in major abdominal surgery

• Requires controlled mechanical ventilation - less reliable in spontaneously breathing patients
• Compromised by cardiac arrhythmias (beat-to-beat variation from arrhythmia confounds respiratory variation)
• Better accuracy for 500 mL fluid challenges than 250 mL (may miss small responses)
• Affected by vasomotor tone changes, peripheral vasoconstriction (hypothermia, vasopressors), and poor peripheral perfusion
• Less reliable with low tidal volumes (< 8 mL/kg) or high PEEP - same constraints as PPV/SVV
• Not validated in open chest, cor pulmonale, or right heart failure

Summary

• Miller's Anesthesia, 10e, p. 5461 (Photoplethysmography section)
• Felippe et al. J Clin Monit Comput. 2025 [PMID: 40778974] - Systematic Review & Meta-Analysis

Thermodilution Method of Measuring Cardiac Output

The Underlying Principle - Indicator Dilution

If a bolus of an indicator is rapidly and thoroughly mixed with a moving fluid upstream from a detector, the concentration of that indicator at the detector rises sharply then exponentially falls back to zero. The area under the time-concentration curve is a function of the volume of indicator injected and the flow rate of the moving stream.

• Larger indicator volume → greater area under curve
• Faster flow (higher CO) → smaller area under curve (indicator is diluted and swept away quickly)

The PAC (Swan-Ganz Catheter) - Anatomy Relevant to Thermodilution

Bolus Thermodilution - Step-by-Step

Step 1: Setup

• Confirm PAC is correctly positioned (proximal port in RA, thermistor in PA)
• Connect the thermistor to a bedside cardiac output computer
• Prepare 10 mL of injectate: iced saline (0°C) or room temperature normal saline / 5% dextrose
• Enter the computation constant into the CO computer (accounts for injectate volume, temperature, catheter dead space, catheter type)

Step 2: Injection

• Inject 10 mL rapidly (< 4 seconds) through the proximal (CVP/RA) port
• The cold bolus enters the right atrium, mixes with blood, flows through the right ventricle, and reaches the pulmonary artery

Step 3: Detection

• The thermistor at the PA catheter tip detects the downstream temperature drop as the cold bolus arrives
• It records a temperature-time curve: temperature falls sharply then gradually returns to baseline

Step 4: Calculation - The Stewart-Hamilton Equation

The Key Inverse Relationship:

• High CO → cold bolus swept past thermistor quickly → small area under curve → high Q_T calculated
• Low CO → cold bolus lingers → large area under curve → low Q_T calculated

Temperature-Time Curve Morphology

1. Rapid downstroke - sharp temperature drop on arrival of cold bolus
2. Smooth upstroke - gradual return to baseline as bolus washes out
3. Return to baseline - complete washout

• Prolonged/flat curve → low CO or tricuspid regurgitation (bolus recirculates)
• Irregular/jagged → arrhythmia, incomplete mixing
• Early return to baseline → intracardiac shunt (bolus bypasses normal pathway)

Cold vs Room Temperature Injectate

Practical Tips - Avoiding Errors

1. Average 2-3 measurements taken at random points in the respiratory cycle (respiratory variation affects pulmonary blood flow and temperature)
2. Inject within 4 seconds - slow injection smears the curve and overestimates CO
3. Avoid injection during rapid fluid infusion or electrocautery
4. Tends to overestimate CO at low values (systematic bias at CO < 2.5 L/min)
5. Tricuspid regurgitation causes recirculation of injectate → falsely high CO reading
6. Intracardiac shunts cause early indicator loss → inaccurate results

Continuous Thermodilution CO (CCO)

• Instead of cold bolus injection, it intermittently heats blood using a tiny electrical filament
• The thermistor downstream correlates heat input with temperature change
• Computer calculates continuous CO and updates the display every 30-60 seconds (averaged over 3-minute intervals)
• Agrees well with conventional bolus thermodilution
• Eliminates the need for repeated injectate injections and nursing workload

Transpulmonary Thermodilution (TPTD) - PiCCO Method

Summary Comparison Table

• Schwartz's Principles of Surgery, 11e (Measurement of Cardiac Output by Thermodilution, p. 469-470)
• Mulholland & Greenfield's Surgery, 7e (Cardiac Function section)
• Schwartz's Principles of Surgery (Transpulmonary Thermodilution section, p. 470)