Date Published

September 25, 2025

Updated For

ALS PCS Version 5.4

#SWORBHPTips

That's a Wrap!

Thank you for following along in this series! We hope it has been helpful and armed you with new knowledge to bring to these difficult resuscitation calls.

H's

  • Hypothermia
  • Hypo/Hyperkalemia
  • Hydrogen Ion
  • Hypoxia
  • Hypovolemia

T's

  • Toxins
  • Tension Pneumothorax
  • Tamponade
  • Thrombosis (Pulmonary)
  • Thrombosis (Cardiac)

Recap

  • The H's and Ts is an approach to address the nebulous "other known reversible causes of arrest not addressed" within the Primary Clinical Considerations of the Medical Cardiac Arrest medical directive 
  • Not all Hs and Ts require very early transport, depending on whether cause can be truly suspected and/or some can be treated/reversed by paramedics.

Important Themes

  • The direction to consider leaving early, aborting your high quality resuscitation needs to be balanced with the potential benefit of transporting for treatment of suspected reversible cause
    • THEREFORE, direction to leave early is only in place for when the suspected cause of arrest is suspected to be reversible, not able to be treated by paramedics AND the suspicion for reversible cause is VERY HIGH
    • For all other arrests, please utilize our excellent high-quality resuscitation per the Medical Cardiac Arrest Medical Directive
    • Remember that irrespective of consideration for reversible cause, if your resuscitation is not able to be optimized, to consider transport (ie. Cannot adequately ventilate)
  • Staying on scene with sub-optimal resuscitation will not benefit the patient
  • This direction was for Medical causes of arrest. Please follow the Trauma Medical Cardiac Arrest Medical Directive for management of traumatic VSA patients

When to Leave Early

Hypothermia

YES – if arrest thought to be FROM the cold

Toxins

YES - if non-opiate or opiate + non-opiate overdose

Hypokalemia

NO- unable to determine if present

Tension Pneumothorax

PCP: YES – if VERY HIGH clinical suspicion

ACP: No – Can treat on-scene

Hyperkalemia

PCP: YES – Leave early if VERY HIGH suspicion

ACP: NO – Can treat on-scene

Tamponade

NO - unable to determine if present

Hydrogen Ion

NO - Utilize standard resuscitation

Thrombosis (Pulmonary)

YES – only of INCREDIBLY HIGH suspicion

Hypoxia

NO - Can treat on scene*

Thrombosis (Cardiac)

Yes – only if pre-arrest 12-Lead ECG with STEMI along with symptoms of cardiac ischemia

Hypovolemia

YES - only if VERY HIGH suspicion 

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