PeRLS 2025 (ASA): What's New in Perioperative Resuscitation Guidelines

Key Takeaways#

Ventilation, compressions, and "compression time"

• Ventilation during cardiac arrest: ventilate at 10-12 breaths/min and avoid hyperventilation (>16 breaths/min).
• Cardiac arrest in prone position: start CPR in the prone position, without turning to supine, to reduce delays.
• POCUS/echo during CPR: can be used, as long as the pause in compressions is ≤10 s.

Doses and escalation in critical perioperative scenarios

• Perioperative bradycardia: atropine with different doses depending on the scenario.

  • 0.5 mg IV for significant bradycardia (HR < 40 bpm or HR < 50 bpm with hypotension).
  • 1.0 mg IV when imminent/emergent arrest is suspected, with rapid escalation.
  • Note: do not use atropine in established arrest (follow ACLS).

• Anaphylaxis: epinephrine with defined initial dose and rapid escalation.

  • Epinephrine IV 0.05 to 0.1 mg or 0.2 to 0.5 mg IM, with rapid escalation (e.g., doubling).

• High neuraxial block with "imminent arrest": early atropine 1 mg IV and epinephrine 100-200 mcg IV, with dedicated algorithm.

Toxicities and specific conditions with operational standardization

• LAST: 20% lipid emulsion formalized and "modified ACLS", including bolus/infusion, maximum dose, and adjustments in vasopressors and antiarrhythmics.
• Malignant hyperthermia: dantrolene with loading dose and checklist, with recommendation of dantrolene 2.5 mg/kg IV and systematization of associated interventions.

Hemorrhage and trauma

• Arrest in trauma setting with suspected hemorrhage: target permissive BP until hemostasis.

  • Consider permissive hypotension (MAP ~50 or SBP ~70 mmHg) until bleeding is controlled.
  • Prioritize reversible causes in traumatic arrest.

Why PeRLS 2025 matters in the operating room#

Perioperative cardiac arrest remains a rare event, but with potentially catastrophic outcomes. The guideline reports an approximate incidence of 2 to 13 per 10,000 anesthetics and mortality to discharge that can vary widely (~32 to 75%), depending on context.

The distinguishing feature of the operating room is that many causes are recognizable and reversible within minutes, from hypoxia due to airway issues to pharmacological toxicities and acute hemorrhage, but the window is short.

The PeRLS 2025 update, published in the December 2025 edition of Anesthesiology, is described as the third iteration conducted with structured methodology (PICO questions, recommendations, and algorithm updates).

Below, we provide a direct summary of the changes/updates made explicit in 2025. Remember that this post does not replace the need to read the complete document, which includes all full flowcharts.

What the 2025 version brings#

Hypovolemia: volume responsiveness-guided resuscitation

Suggests using dynamic indices (e.g., PPV) to guide fluids during hypotension in adults.

Important to be aware of limitations: RV failure, open chest, intra-abdominal hypertension, and arrhythmias.

Ventilation during cardiac arrest: warning against hyperventilation

Suggests ventilating at 10-12 breaths/min and avoiding hyperventilation (>16 breaths/min) during arrest.

Perioperative bradycardia: atropine with different doses for each scenario

• 0.5 mg IV for significant bradycardia (HR < 40 bpm or HR < 50 bpm with hypotension).
• 1.0 mg IV when imminent/emergent arrest is suspected, with rapid escalation.

Note: do not use atropine in established arrest (follow ACLS).

Anaphylaxis: IV epinephrine with defined initial dose and rapid escalation

Recommends epinephrine IV 0.05 to 0.1 mg or 0.2 to 0.5 mg IM with rapid escalation (e.g., doubling).

LAST: 20% lipid emulsion formalized + "modified ACLS"

Recommends 20% lipid emulsion and describes bolus/infusion and maximum dose, along with adjustments in vasopressors and antiarrhythmics.

Malignant hyperthermia: dantrolene with loading dose and checklist

Recommends dantrolene 2.5 mg/kg IV and systematizes associated interventions.

Arrest in trauma setting with suspected hemorrhage: permissive BP target until hemostasis

Suggests permissive hypotension (MAP ~50 or SBP ~70 mmHg) until bleeding is controlled.

And emphasizes prioritization of reversible causes in traumatic arrest.

High neuraxial block: early atropine/epinephrine when "imminent arrest"

Suggests atropine 1 mg IV and epinephrine 100-200 mcg IV in this context, with dedicated algorithm.

Cardiac arrest in prone position: start CPR in prone position

Suggests starting compressions without turning to supine, to reduce delays.

POCUS/echo during CPR: allowed, but without "stealing time" from compression

Use permitted, as long as the pause in compressions is ≤10 s.

Table 1: 2025 Changes#

Rapid diagnosis in the perioperative period: "9H + 9T" (main causes of cardiac arrest)#

The guideline organizes reversible perioperative causes into 9 Hs and 9 Ts, with operating room examples.

Reviewing the algorithms#

1) Perioperative bradycardia

Practical approach (per guideline):

Immediate actions

• 100% O₂
• Check ventilation/ETCO₂
• Hemodynamics
• Anesthetic depth and vagal/surgical triggers
• Relevant perioperative causes

Atropine when severe/unstable

• 0.5 mg IV for significant bradycardia (HR < 40 bpm or HR < 50 bpm with hypotension)
• 1.0 mg IV when imminent arrest is suspected, with rapid escalation.

Safety point

• Atropine not recommended in established arrest (follow ACLS).

Escalation

• Consider pacing when available (the text discusses potential superiority in certain scenarios) and follow algorithm progression.

Table 2: Atropine in perioperative bradycardia (PeRLS 2025)

2) Perioperative tachycardia

The algorithm is structured as:

First filter

• Hemodynamic instability: priority is synchronized cardioversion.
• If pulseless: move to cardiac arrest algorithm.

If not unstable

• Investigate perioperative causes and classify by:

  • Narrow vs wide QRS
  • Regular vs irregular Guiding therapy per the ACLS flowchart.

3) Perioperative anaphylaxis

The guideline emphasizes variability in clinical presentations and the possibility of rapid deterioration.

The algorithm is divided into three blocks:

Pre-arrest (severe reaction/shock)

• Discontinue agent

• Call for help

• 100% O₂

• Volume (crystalloid ~20 ml/kg as needed)

• Epinephrine in escalating doses:

  • Initially IV 0.05 to 0.1 mg or 0.2 to 0.5 mg IM
  • Repeated doses of 0.1 to 0.3 every 3 to 5 min
  • Possibility of continuous infusion (0.05 to 0.3 μg·kg⁻¹·min⁻¹)

• If hypotension persists: another vasopressor may be added (norepinephrine or vasopressin).

Adjuncts

• H1 antagonist: diphenhydramine 50 mg IV
• H2 antagonist: famotidine 20 mg IV
• Corticosteroid: hydrocortisone 50 to 150 mg or methylprednisolone 1 to 2 mg/kg
• Bronchodilator
• Glucagon if on beta-blocker

Cardiac arrest

• CPR
• Epinephrine 1 mg every 3-5 min
• Remaining ACLS steps

After stabilization

• Collect histamine/tryptase (timing)
• ICU monitoring for 24h after severe event

4) LAST: Local anesthetic systemic toxicity

Pre-arrest

• Discontinue local anesthetic
• Call for help
• 100% O₂
• Avoid hyperventilation
• Treat seizures with benzodiazepines
• Avoid large dose of propofol in cardiovascular instability
• Notify ECMO team

20% Lipid emulsion (core of algorithm)

• Bolus 1.5 ml/kg (2-3 min) then

• Infusion 0.25 ml·kg⁻¹·min⁻¹

• Maintain until stable and for 10 min after stabilization

• If instability persists:

  • Repeat bolus
  • Double continuous infusion if necessary

• Maximum dose approximately 10-12 ml/kg (lean body mass)

• Administer 10 mcg epinephrine boluses if SBP < 90 mmHg

• Consider bicarbonate if pH < 7.2 or hyperkalemia

If cardiac arrest

• CPR and ACLS with listed modifications:

  • Reduced epinephrine doses 0.1 to 0.3 mg
  • Avoid vasopressin, beta-blocker, calcium channel blocker, lidocaine
  • Prefer amiodarone
  • Consider ECMO if available

Table 3: LAST with 20% lipid emulsion and modified ACLS

5) Hemorrhage and arrest in trauma setting

The guideline emphasizes that in arrest in trauma setting it may be necessary to prioritize correction of reversible causes (such as hemorrhage, tension pneumothorax, tamponade), and that compressions may have relatively lower priority in some described scenarios.

2025 Recommendation

• In adults with suspected hemorrhage, consider permissive hypotension (MAP ~50 or SBP ~70 mmHg) until bleeding control, as long as there are no contraindications (such as TBI).

Tranexamic acid

• Regimen: 1 g over 10 min + 1 g over 8 h
• Greatest effectiveness when administered within the first 3 hours and "no later than 4 hours" after trauma.

6) High neuraxial block

Pre-arrest (initial management)

• Assess bradycardia, hypotension, and neuromuscular weakness
• Discontinue anesthetic infusion or sedation
• Administer 100% O₂
• Intubate if respiratory distress or hypoxemia
• Treat bradycardia with atropine 1 mg IV or administer epinephrine 100-200 mcg IV
• Consider transcutaneous or transvenous pacing for all symptomatic patients

During cardiac arrest

• Start CPR
• Administer atropine 1 mg IV
• Administer epinephrine 1 mg IV if no response

Post-arrest (subsequent management)

• Consider starting epinephrine infusion in the range of 0.05 to 0.1 mcg·kg⁻¹·min⁻¹

7) Malignant hyperthermia

Signs supporting suspicion

• Hypercapnia with abrupt ETCO₂ rise
• Tachycardia
• Tachypnea in non-paralyzed patients
• Muscle rigidity/masseter spasm
• Hyperthermia

Pre-arrest (initial management)

Ventilation/anesthesia

• Discontinue volatile anesthetics and switch to IV anesthetic (if necessary)
• Stop the procedure when feasible
• Disconnect from ventilator and manually ventilate with separate O₂ source
• Switch to "clean" dedicated ventilator, transport ventilator, or ICU ventilator (if available)
• Target ETCO₂ 50-60 mmHg

Medication (specific treatment)

• Administer dantrolene (sodium) 2.5 mg/kg IV through the largest available venous access

• Repeat dantrolene bolus, titrating to symptom resolution

  • The table indicates suggested upper limit of 10 mg/kg, but up to 30 mg/kg may be needed

• Avoid calcium antagonists

Temperature control

• Apply ice packs to groin, axillae, and neck
• Use cooling devices (if available) for target temperature management
• Consider cold gastric lavage via NGT or cold peritoneal lavage when feasible
• Stop cooling upon reaching 38°C to avoid "overshoot"

Hyperkalemia

• Administer calcium chloride 10 mg/kg IV
• Insulin 0.1 U/kg
• D50W 50 ml in adults or 1 ml/kg in pediatrics
• Repeat as needed

Metabolic acidosis

• Administer bicarbonate (HCO₃) 100 mEq in adults and titrate to pH 7.2

Myoglobinuria with oliguria

• Insert urinary catheter
• Increase fluid resuscitation rate
• Initiate invasive pressure monitoring when feasible
• Consider HCO₃ to neutralize urinary pH
• Consider IV mannitol

Disseminated intravascular coagulation

• Institute supportive measures

Specialized support

• Contact MH support/hotline

Post-crisis/post-event (subsequent management)

• Monitor for recrudescence for 72 hours
• Maintain dantrolene 1 mg/kg every 6 hours for at least 24 hours
• Treat and cool as needed

After resolution:

• Consider in vitro contracture test (muscle biopsy with caffeine-halothane)
• Consider molecular genetic testing for mutation analysis in family members (the table records sensitivity of 25%)

8) Management of shock from left ventricular dysfunction (acute left heart failure in perioperative period)

Hemodynamic profile

• Shock refractory to volume with low pulse pressure variation (low PPV)

Management principles

• Correct hypovolemia before starting drugs: in patients with compromised LV function, the guideline states that hypovolemia must be treated before any pharmacological therapy.
• If patient is hypotensive and euvolemic/hypervolemic: prioritize agents that increase inotropy, listed in the text as dobutamine, epinephrine, milrinone, and norepinephrine.
• If systemic vascular resistance is elevated and patient tolerates BP reduction: use afterload-reducing agents, cited as nicardipine or hydralazine.
• Reduce ventricular stretch when necessary: the guideline mentions that diuretics may be needed to reduce ventricular distension/stretch.
• Significant diastolic dysfunction: frequently treat with lusitropic agent, cited as milrinone; the text describes that lusitropic agents improve relaxation, promote better filling, increased stroke volume and cardiac output.
• If no response and recovery potential exists: consider mechanical circulatory support, including intra-aortic balloon pump, ventricular assist devices, and extracorporeal support/ECMO.

9) Management of shock from right ventricular dysfunction (acute right heart failure in perioperative period)

Highlighted perioperative mechanism May occur due to acute increase in RV afterload: venous air embolism, fat embolism, cement, amniotic material, or thromboembolism.

The guideline adds that in approximately 5% of cases, acute thromboembolism causes cardiac arrest, most frequently in PEA.

Management principles

• Volume should be used judiciously: the guideline emphasizes that not all RV failure requires volume to "increase preload".
• If RV dysfunction is related to fluid excess: consider diuretics to reduce ventricular work and favor forward flow to the LV.
• Reduce RV afterload: use inhaled pulmonary vasodilators (nitric oxide and epoprostenol) to reduce pulmonary vascular resistance and thus reduce RV afterload.
• Increase RV contractility: use inotropes (dobutamine or epinephrine).
• Maintain systemic perfusion: use systemic arterial vasoconstrictors to maintain MAP and vital organ perfusion.
• Vasopressin (highlighted characteristic): is described as a vasopressor that selectively causes vasoconstriction in systemic circulation and spares pulmonary circulation.
• Refractory to medical management: consider ECMO or RV assist device.

10) Management of thromboembolism/pulmonary embolism

Assessment (when to suspect)

• Significant hemodynamic instability in high-risk cases
• Tachycardia and sudden ETCO₂ drop
• Consider echocardiography (TTE/TEE) to support diagnosis

Initial management: pre-arrest

• Stop gas insufflation and flood surgical field
• Administer 100% O₂
• Intubate if respiratory distress or hypoxemia
• Positioning: Trendelenburg (head down) and rotation to left lateral decubitus
• Maintain blood pressure with IV fluids, vasopressors, and β-adrenergic agents
• Consider transfer to hyperbaric chamber if immediately available in case of gas embolism

If progresses to cardiac arrest

• Start CPR and consider extracorporeal circulation or emergent thrombectomy

Subsequent management (after initial stabilization)

• Consider the right ventricular shock algorithm as reference for hemodynamic management

Cardiac arrest in prone position: reducing delay to compressions#

A very pragmatic point in this edition: in arrest with patient in prone position, the guideline suggests starting CPR in prone, rather than delaying compressions to turn patient to supine.

The text notes limitations (for example, cardioversion/defibrillation may be less effective in prone), but the central message is to reduce delay to compressions.

Ventilation during CPR: 10-12 breaths/min and avoid hyperventilation#

The 2025 update suggests ventilating at 10-12 breaths/min and avoiding >16 breaths/min during arrest.

The highlighted rationale is physiological and operational: hyperventilation favors auto-PEEP, reduces venous return, and may impair ROSC; the guideline still recognizes situational exceptions (e.g., specific conditions cited in the text), but the baseline guidance remains.

Ultrasound/Echo during CPR: can help, but pause must be short#

The guideline permits use of POCUS/echo as a diagnostic tool during CPR, as long as the pause in compressions is limited to 10 seconds.

Reversible causes that ultrasound can identify during cardiac arrest:

• Esophageal intubation
• Abdominal bleeding
• Pneumothorax
• Pulmonary embolism
• Tamponade

In addition to differentiating true asystole from fine VF.

Final message#

The PeRLS 2025 guideline organizes perioperative resuscitation as a set of rapid decisions, anchored in reversible causes characteristic of the operating room, and formalizes operational recommendations with standardized language and dedicated algorithms.

It is required reading for every anesthesiologist. If you need to remember any recommendation, just consult Anestcopilot!