Prehospital use of minimally invasive direct cardiac massage (MID-CM): A pilot study

Background: Internal cardiac compressions are more efficient than closed chest compressions (CCC) in cardiac arrest (CA). Aim of the study: To evaluate the prehospital feasibility of performing a new method of minimally invasive direct cardiac massage (MID-CM® TheraCardia Inc.). Methods: Prospective non-randomized open study, after ethical committee approval. Inclusion of 18-85 years old patients in witnessed CA if BLS > 5 min and unsuccessful ACLS > 20 min after CA. The MID-CM is an atraumatic manual cardiac pumping system deployed in the thoracic cavity through a small incision. Evaluation of: ease of insertion and performing MID-CM, complications, end-tidal CO₂ (PETCO₂), non invasive arterial blood pressure (NIBP) and return of spontaneous circulation (ROSC). Values are mean ± SD (min-max). Results: Twenty-five patients included. Mean age 59 ± 16 years (26-85); BLS started at 8 ± 5 min (0-20), compressions started at 47 ± 10 min (29-74) after CA. Dissection and insertion was fast and easy (<1 min). Deployment of the MID-CM was difficult in two patients because of pericardium adhesions and cardiomegaly. In six patients compressions were more difficult because of a 'stone heart' phenomenon. Compressions were possible during ambulance transport of four patients. There was a good palpable carotid pulse in all patients receiving internal compressions. There was a trend in increase of PETCO₂ compared to CCC. NIBP could be measured during MID-CM compressions in 9 patients (systolic > 85 mmHg), never during CCC. Seven patients had a ROSC, but only four patients were admitted alive. There was no long term survival. One patient had a serious complication (heart rupture). Discussion: Prehospital use of MID-CM is possible, but it is not comparable to any other resuscitation technique. Training of medical teams is mandatory to obtain good skills and to avoid complications. Further studies are necessary to evaluate efficiency and survival compared to closed chest compressions.