Controlled sequential elevation of the head and thorax combined with active compression decompression cardiopulmonary resuscitation and an impedance threshold device improves neurological survival in a porcine model of cardiac arrest

Abstract

Aim of the study: Controlled sequential elevation of the head and thorax (CSE) during active compression decompression (ACD) cardiopulmonary resuscitation (CPR) with an impedance threshold device (ITD) has been shown to increase cerebral perfusion pressure and cerebral blood flow in previous animal studies as compared to the traditional supine position. The potential for this novel bundled treatment strategy to improve survival with intact neurological function is unknown.

Methods: Female farm pigs were sedated, intubated, and anesthetized. Central arterial and venous access were continuously monitored. Regional brain tissue perfusion (CerO₂) was also measured transcutaneous. Ventricular fibrillation (VF) was induced and untreated for 10 min. Pigs were randomized to (1) Conventional CPR (C-CPR) flat or (2) ACD + ITD CSE CPR that included 2 min of ACD + ITD with the head and heart first elevated 10 and 8 cm, and then gradual elevation over 2 min to 22 and 9 cm, respectively. After 19 min of CPR, pigs were defibrillated and recovered. A veterinarian blinded to the intervention assessed cerebral performance category (CPC) at 24 h. A neurologically intact outcome was defined as a CPC score of 1 or 2. Categorical outcomes were analyzed by Fisher's exact test and continuous outcomes with an unpaired student's t-test.

Results: In 16 animals, return of spontaneous circulation rate was 8/8 (100%) with ACD + ITD CSE and 3/8 (25%) for C-CPR (p = 0.026). For the primary outcome of neurologically intact survival, 6/8 (75%) pigs had a CPC score 1 or 2 with ACD + ITD CSE versus 1/8 (12.5%) with C-CPR (p = 0.04). Coronary perfusion pressure (mmHg, mean ± SD) was higher with CSE at 18 min (41 ± 24 versus 10 ± 5, p = 0.004). rSO₂ (%, mean ± SD) and ETCO₂ (mmHg, mean ± SD) values were higher at 18 min with CSE (32 ± 9 versus 17 ± 2, p = 0.01, and 55 mmHg ± 10 versus 21 mmHg ± 4, p < 0.001), respectively.

Conclusions: The novel bundled resuscitation approach of CSE with ACD + ITD CPR increased favorable neurological survival versus C-CPR in a swine model of cardiac arrest.

Keywords: Active compression–decompression CPR; Cardiac arrest; Cardiopulmonary resuscitation; Cerebral perfusion; Controlled sequential elevation; Head Up CPR; Head and thorax elevation; Impedance threshold device; Mechanical CPR.

Figure 1:

Diagram of the customized elevation device in the flat, lowest elevation and highest elevation

Figure 2:

Representative graphic depicting the study protocol.

Figure 3:

Representative histogram depicting the cerebral performance category (CPC) scores of each animal. CPC score is graded on a scale from 1 (No neurological impairment) to 5 (No ROSC/Dead before 24-hour assessment).

Figure 4:

Kaplan Meier survival curves for two animal groups 1) Active compression-decompression (ACD) CPR with an impedance threshold device (ITD) and controlled sequential elevation (CSE) 2) Conventional (C) CPR in the flat position.

Figure 5:

Hemodynamic and resuscitation parameter values recorded at baseline prior to induction of cardiac arrest, and during each minute of CPR, graphed over time.