The Use of Vasopressor Agents During Cardiopulmonary Resuscitation

Impact of catecholamines in cardiac arrest due to acute asphyxia--a study in piglets

BACKGROUND

Early intravenous epinephrine administration may help to achieve return of spontaneous circulation in cardiac arrest (CA). However, venous access can be challenging in small children. This study investigates the effect of intravenous and intramuscular epinephrine in treatment of asphyxial CA.

METHODS

Twenty-eight, 2-5-weeks-old, anesthetized piglets were asphyxiated by ventilation withdrawal. CA was untreated for 8 min, followed by 2 min of basic life support. Following this, epinephrine iv (10 μg·kg(-1) , group IV), epinephrine im (100 μg·kg(-1) , group IM), or normal saline (group NS) were administered. Further doses of epinephrine were given in group IV every 4 min, in group IM after 10 min if required. After twenty-two minutes of CA, iv epinephrine was given to all animals still in CA. Outcome measures were survival and epinephrine plasma concentrations.

RESULTS

Ten animals regained spontaneous circulation after 2 min of basic life support. Therefore, no drug treatment was administered (drop out). Resuscitation was effective in 2 pigs of group IM (n = 6), in 6 of group NS (n = 8) and in all of group IV (n = 4). Nonsurvivors had higher epinephrine (P < 0.01) and norepinephrine (P < 0.01) plasma concentrations prior to start of resuscitation. Median increase in epinephrine plasma concentration from T0 to T5 was 138, 134, and 29 nm in group IV, IM, and NS, respectively.

CONCLUSIONS

Intravenous and intramuscular administered epinephrine led to similar increase in plasma concentrations during resuscitation of asphyxial CA without hemodynamic or survival benefit. High endogenous epinephrine and norepinephrine plasma concentrations were negative predictors for survival.

Adrenaline increases blood-brain-barrier permeability after haemorrhagic cardiac arrest in immature pigs

BACKGROUND

Adrenaline (ADR) and vasopressin (VAS) are used as vasopressors during cardiopulmonary resuscitation. Data regarding their effects on blood-brain barrier (BBB) integrity and neuronal damage are lacking. We hypothesised that VAS given during cardiopulmonary resuscitation (CPR) after haemorrhagic circulatory arrest will preserve BBB integrity better than ADR.

METHODS

Twenty-one anaesthetised sexually immature male piglets (with a weight of 24.3 ± 1.3 kg) were bled 35% via femoral artery to a mean arterial blood pressure of 25 mmHg in the period of 15 min. Afterwards, the piglets were subjected to 8 min of untreated ventricular fibrillation followed by 15 min of open-chest CPR. At 9 min of circulatory arrest, piglets received amiodarone 1.0 mg/kg and hypertonic-hyperoncotic solution 4 ml/kg infusions for 20 min. At the same time, VAS 0.4 U/kg was given intravenously to the VAS group (n = 9) while the ADR group received ADR 20 μg/kg (n = 12). Internal defibrillation was attempted from 11 min of cardiac arrest to achieve restoration of spontaneous circulation. The experiment was terminated 3 h after resuscitation.

RESULTS

The intracranial pressure (ICP) in the post-resuscitation phase was significantly greater in ADR group than in VAS group. VAS group piglets exhibited a significantly smaller BBB disruption compared with ADR group. Cerebral pressure reactivity index showed that cerebral blood flow autoregulation was also better preserved in VAS group.

CONCLUSIONS

Resuscitation with ADR as compared with VAS after haemorrhagic circulatory arrest increased the ICP and impaired cerebrovascular autoregulation more profoundly, as well as exerted an increased BBB disruption though no significant difference in neuronal injury was observed.

Experimental cardiac arrest treatment with adrenaline, vasopressin, or placebo

BACKGROUND

The effect of vasoconstrictors in prolonged cardiopulmonary resuscitation (CPR) has not been fully clarified.

OBJECTIVES

To evaluate adrenaline and vasopressin pressure effect, and observe the return of spontaneous circulation (ROSC).

METHODS

A prospective, randomized, blinded, and placebo-controlled study. After seven minutes of untreated ventricular fibrillation, pigs received two minutes cycles of CPR. Defibrillation was attempted (4 J/kg) once at 9 minutes, and after every cycle if a shockable rhythm was present, after what CPR was immediately resumed. At 9 minutes and every five minutes intervals, 0.02 mg/kg (n = 12 pigs) adrenaline, or 0.4 U/kg (n = 12) vasopressin, or 0.2 mL/kg (n = 8) 0.9% saline solution was administered. CPR continued for 30 minutes or until the ROSC.

RESULTS

Coronary perfusion pressure increased to about 20 mmHg in the three groups. Following vasoconstrictors doses, pressure level reached 35 mmHg versus 15 mmHg with placebo (p < 0.001). Vasopressin effect remained at 15-20 mmHg after three doses versus zero with adrenaline or placebo. ROSC rate differed (p = 0.031) among adrenaline (10/12), vasopressin (6/12), and placebo (2/8). Time-to-ROSC did not differ (16 minutes), nor the number of doses previously received (one or two). There was no difference between vasoconstrictors, but against placebo, only adrenaline significantly increased the ROSC rate (p = 0.019).

CONCLUSION

The vasoconstrictors initial pressure effect was equivalent and vasopressin maintained a late effect at prolonged resuscitation. Nevertheless, when compared with placebo, only adrenaline significantly increased the ROSC rate.