OPEN-CHEST CARDIAC MASSAGE WITHOUT MAJOR THORACOTOMY - METABOLIC INDICATORS OF COROLLARY AND CEREBRAL PERFUSION

Objective: to compare the coronary and cerebral perfusion achieved usi ng a novel method of minimally-invasive, direct cardiac massage to tha t obtained using bimanual, open-chest cardiac massage. Design: prospec tive, controlled animal study with repeated measures. Setting: univers ity research laboratory. Subjects: large domestic swine. Interventions : aortic, coronary sinus, jugular venous and pulmonary artery catheter s were placed. Following an equilibration period, ventricular fibrilla tion was induced. After 4 min of untreated ventricular fibrillation, a nimals underwent bimanual, open-chest cardiac massage (N = 6) or minim ally-invasive, direct cardiac massage using a novel device for direct cardiac compression (N = 6). Adrenaline was administered at a dose of 1 mg intravenously every 5 min. Measurements: systemic metabolic param eters, (arterial P-O2, P-CO2 and lactate concentration) and coronary s inus and jugular venous metabolic parameters (pH, PVO2, SVO2, PVCO2 an d lactate concentration) were measured and calculated (coronary sinus/ jugular-arterial SVO2, coronary sinus/jugular-arterial P-CO2 and lacta te differences) at baseline and at 10, 20 and 30 min following inducti on of ventricular fibrillation. Animals were euthanised after 30 min w ith no attempt at defibrillation. Main Results: oxygen tension and oxy gen saturation of coronary sinus blood declined significantly during t he experimental period, but no differences were noted between treatmen t groups. The coronary sinus-arterial oxygen saturation difference inc reased during the study with no significant differences between groups . Coronary sinus P-CO2 and the coronary sinus-arterial P-CO2 differenc e increased significantly in both experimental groups during cardiac m assage. No inter-group differences were noted. A similar relationship was noted in coronary sinus lactate values. The coronary sinus-arteria l lactate difference displayed a positive balance at all intervals wit h no differences noted between group values. The oxygen tension and ox ygen saturation of jugular venous blood, were reduced from baseline le vels with both treatments. The jugular-arterial oxygen saturation diff erence increased in both groups compared to baseline values. Between g roup values were significantly different only at the 20 min interval. Both the jugular venous P-CO2 and the jugular-arterial P-CO2 gradient were elevated at all intervals, but no inter-group differences were no ted. Jugular venous lactate concentration rose steadily with time in b oth groups. No significant increase in the jugular-arterial lactate gr adient was noted at any time point. Conclusions: minimally-invasive, d irect cardiac massage provides coronary and cerebral perfusion similar to that achieved using standard open-chest cardiac massage. This meth od may provide a more effective substitute for standard, closed-chest cardiac massage in cases of refractory cardiac arrest. (C) 1997 Elsevi er Science Ireland Ltd.