Cipani et al 2019 - Blood flow maintenance by CPR

Question 1

Summarise Cipani et al 2019

Answer 1

Published in Journal of the Intensive Care Society

Systematic review looking into the various theories of blood flow generation during chest compressions

Cardiac pump
Thoracic pump
Lung pump
Left atrial pump
Respiratory pump

Analysis of mechanical CPR device
- Mechanical piston
- Load-distributing band
- Active ACD

Main take homes:
- No one model fits every patient
- No benefit of mechanical over manual CPR but may be useful where there are barriers to adequate manual CPR

Question 2

Outline the cardiac pump theory

Answer 2

Heart compressed between sterum and spine
Diastolic phase where intraventricular pressure reduces - suction

Question 3

Outline the thoracic pump theory

Answer 3

Increased intrathoracic pressure during compressions forces the blood from thoracic vessels into the circulation

Question 4

Outline the lung pump theory

Answer 4

Chest compressions cause a rise in intrathoracic pressure is transmitted to all structures

Inlet - pulmonary valve
Compression chamber - lungs, left side of the heart
Outlet - aortic valve

Question 5

Outline the left atrial pump theory

Answer 5

Concept of ‘‘left atrial pump’’, based on the evidence of simultaneous forward flow through an open mitral valve and backward pulmonary venous flow.

Question 6

Outline the respiratory pump theory

Answer 6

Generated by negative pressure due to chest recoil

Question 7

Outline the mechanical CPR options

Answer 7

Mechanical piston
- Based on cardiac pump theory
- Plunger placed over the sternum
- No active mechanic decompression
- No benefit over manual CPR

Load-distributing band
- Based on thoracic pump theory
- No difference over manual CPR

Active ACD
- Thoracic pump but coupled with negative intrathoracic pressure
- Suction cup performs active decompression
- Some manual devices but harder work than standard CPR
- LUCAS
- Still no benefit, unless used with ITD