see also: [[APLS]], [[Neonatal life support|neoresus]], [[Cardiac arrest]] and [[Cardiac arrest#post-arrest care|ROSC care]]
# ALS algorithm
![[Pasted image 20230824214637.png]]
# Hs and Ts
> [!warning] Reversable causes of ACS
> **mnemonic**:: ABCDEHTTT
>
> **A, B** - Hypoxia (resp arrest (eg opiate OD), tension pneumo, PE)
>
> **C** - Cardiac (MI, tamponade, hypovolemia)
>
> **D** - hypoglycemia/hyperglycemia (“DEFG”), temperature (hypothermia)
>
> **E** - Electrolytes (hyper/hypo K)
>
> **H** - Hydrogen ions (acidosis)
>
> **T, T,T** - Trauma, Toxins/tablets
| Hs | Ts |
| --------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- |
| - hypovolaemia<br>- hypoxia<br>- Hydrogen ion<br>- Hyper/hypo-K<br>- hypothermia<br>- hypoglycaemia | - tamponade<br>- tension pneumothorax<br>- thrombosis (coronary or PE)<br>- toxins<br>- trauma |
# CPR effectiveness
**CPR:**
rate: 100-120/min
1/3 depth of chest
**ETCO2:**
- correlated with coronary perfusion pressure and survival from cardiac arrest
- 10-20 mmHg : good quality
- \>20 at 20 min suggests good prognosis
- < 10 at 20 min suggests poor prognosis
**Ventilation:**
while intubated, ventilate at 6-10 breaths/min
**hyperventilation in ALS is harmful** because:
- ↑ intrathoracic pressure impedes *venous return* and *coronary blood flow*
- increases impendance to defibrillation
- potential for barotrauma
# special considerations for cardiac arrest and ALS in pregnancy
see also: [[Airway#Pregnant Airway|Pregnant Airway]], [[Pregnant trauma#Pregnancy effect on resus|Pregnancy effect on resus]], [[Cardiac arrest#pregnancy|Cardiac Arrest → pregnancy]]
in addition to Hs and Ts need to consider
- do we need a [[Resuscitative Hysterotomy]]?
- [[amniotic fluid embolism]]
- [[Pre-eclampsia|Eclampsia]]
- eg hypertensive disorder of pregnancy
- seizure with hypoxia → cardiac arrest
- haemorrhage from liver rupture
- haemorrhage from uterine rupture or [[antepartum haemorrhage|Placenta praevia or placental abruption]]
## modifications to BLS
- left lateral tilt
- biaxillary defib pads (or AP pad under breast instead of over it)
- prepare for emergency perimortem c-section
## specific resus considerations in pregnancy
**airway**
- increased risk of aspiration
- difficult intubation
- decreased FRC makes resp decompensation more rapid, airway access more urgent
**breathing**
- O2 consumption increases
- need to place chest drains higher
**circulation**
- venous return impaired by gravid uterus
- placental arteries more sensitive to catecholamines, will constrict when you give large boluses of adrenaline
- trans-thoracic echocardiography during CPR will be difficult