Adrenaline, cardiac arrest, and evidence based medicine

Does the topical use of epinephrine for sinus floor augmentation affect systemic hemodynamics?

PURPOSE

Although epinephrine is one of the most commonly used vasoconstrictor in association with local anesthesia in dentistry, systemic effects of topical admission of epinephrine for sinus augmentation have not been investigated yet. The purpose of this study was to reveal the safety of epinephrine as a topical vasoconstrictor in sinus augmentation procedures.

PATIENTS AND METHODS

Forty-three healthy patients who require sinus floor augmentation for dental implant placement were included in this study. Patients were divided into 2 groups according to the application of either epinephrine-soaked cottonoid or saline-soaked cottonoid for sinus floor augmentation, and heart rate, systolic, and diastolic pressures were evaluated and compared before, during, and after the procedure.

RESULTS

Although there were changes in heart rate, systolic, and diastolic blood pressures, no statistical significance was observed for neither heart rate nor systolic and diastolic blood pressures (P > 0.05).

CONCLUSIONS

This study showed that the topical use of 1/100,000 epinephrine ensures efficacy by helping the clinician to elevate the sinus membrane and keeps the changes in systemic hemodynamics within safe limitations.

Analysis of prehospital care for cardiac arrest in an urban setting in Japan

BACKGROUND

In Japan, the management of prehospital care for cardiopulmonary arrest (CPA) has recently changed.

STUDY OBJECTIVES

The characteristics of prehospital care for CPA were analyzed to identify predictors of prehospital return of spontaneous circulation (PROSC) and good recovery.

METHODS

The characteristics of prehospital management of 713 out-of-hospital CPA patients in the First Western District of Saitama Prefecture, Japan, were retrospectively analyzed.

RESULTS

Overall, PROSC rate was 9.5% (n = 68), and 2.2% of patients (n = 16) made a good recovery. Significant positive predictors of PROSC were: duration from the first call to hospital arrival, witnessed collapse, ventricular fibrillation at scene, and epinephrine administration. Establishment of supraglottic airway was a significant negative predictor of PROSC. Significant positive predictors of good recovery were younger age, ventricular fibrillation at scene, and PROSC. Changes to the life support protocol based on 2005 guidelines did not affect the outcome.

CONCLUSIONS

Epinephrine was effective in increasing PROSC; however, it did not improve recovery of such patients. The findings also suggest that out-of-hospital care providers should not try to establish a supraglottic airway.

Epinephrine Increases Mortality after Brief Asphyxial Cardiac Arrest in an In Vivo Rat Model

Epinephrine may be detrimental in cardiac arrest. In this laboratory study we sought to characterize the effect of epinephrine and concomitant calcium channel blockade on postresuscitation myocardial performance after brief asphyxial cardiac arrest. Anesthesized rats were disconnected from mechanical ventilation, resulting in cardiac arrest. Resuscitation was attempted after 1 min with mechanical ventilation, oxygen, chest compressions, and IV medication. In experimental series 1 and 2, animals were allocated to 10 or 30 microg/kg epinephrine or 0.9% saline. In series 3, animals received 30 microg/kg of epinephrine and were randomized to 0.1 mg/kg of verapamil or to 0.9% saline. In series 1 and 3, left ventricular function was assessed using transthoracic echocardiography. In series 2, left atrial pressure was measured. Epinephrine was associated with increased mortality (0/8 [0%] in controls, 4/12 [33.3%] in 10 microg/kg animals, and 16/22 [72.8%] in 30 microg/kg animals; P < 0.05), hypertension (P < 0.001), tachycardia (P = 0.004), early transient left atrial hypertension, and dose-related reduction in left ventricular end diastolic diameter (P < 0.05). Verapamil prevented mortality associated with large-dose epinephrine (0% versus 100%) and attenuated early diastolic dysfunction and postresuscitation hypertension (P = 0.001) without systolic dysfunction. Epinephrine appears to be harmful in the setting of brief cardiac arrest after asphyxia.

The roles of alpha- and beta-adrenoceptor stimulation in myocardial ischaemia

beta-Adrenoceptor (AR) ligands have been the mainstay of cardiovascular therapy for decades, with beta-AR antagonist being used for hypertension, angina and myocardial infarction and adrenaline in use for cardiopulmonary resuscitation for nearly 100 years. Ischaemia of the heart through coronary artery occlusion causes cell injury and death through necrosis and apoptosis. Reperfusion of the ischaemic myocardium results in cardiac dysfunction and infarction. Stimulation of alpha- and beta-ARs in the ischaemic heart have variable and inconsistent effects depending on when the agonist is applied. This review describes the different effects of stimulation of the three established beta-AR subtypes (beta(1)-, beta(2)- and beta(3)-ARs) either before ischaemia (preconditioning) or during ischaemia and reperfusion of the heart (postconditioning). Brief periods of ischaemia preceding a major ischaemic episode can have a protective effect against post-ischaemia-reperfusion damage, known as ischaemic preconditioning. This review considers the role of endogenous catecholamines released during preconditioning and the nature of the adrenoceptor subtypes that mediate these effects. The clinical significance of this to the use of beta-AR antagonists is considered. The transduction pathways and effects on apoptosis of the cardioprotective and deleterious effects of AR activation are considered. This commentary reviews the literature and attempts to bring together a unified synopsis of the effects of adrenoceptor stimulation in myocardial ischaemia and the potential clinical relevance.

Adrenaline administration during cardiopulmonary resuscitation: poor adherence to clinical guidelines

BACKGROUND

Adrenaline does not appear to improve the outcome after cardiac arrest in clinical trials in spite of beneficial effects in experimental studies. The objective of this study was to determine whether adrenaline was administered in accordance with advanced cardiac life support (ACLS) guidelines during adult cardiopulmonary resuscitation (CPR).

METHODS

From 15 January to 31 December 2000, all patients at Uppsala University Hospital in whom CPR was attempted were registered prospectively. The duration of CPR was documented in the register and the total dose of adrenaline was retrieved retrospectively from patient records. From these data the average interval between adrenaline doses was calculated.

RESULTS

Data for evaluation of the between-dose interval of adrenaline was available in 53 of 107 registered cardiac arrests. In 68% (36/53) the average between-dose interval was longer than the 3-5 min recommended in the guidelines, and 8% (4/53) received no adrenaline. The median interval between adrenaline doses during CPR was 6.5 min (25th-75th percentile: 5.1-10.4). Adherence to guidelines was lower in out-of-hospital cardiac arrest than in in-hospital cardiac arrest (P = 0.01).

CONCLUSIONS

In the majority of cases adrenaline did not appear to be administered according to current ACLS guidelines.

Cerebral ischaemia in experimental cardiopulmonary resuscitation--comparison of epinephrine and aortic occlusion

The apparent inability of epinephrine to improve outcome after cardiopulmonary resuscitation (CPR) could be caused by direct negative effects on the cerebral circulation. Constant aortic occlusion with a balloon catheter could be an alternative way to improve coronary and cerebral perfusion during CPR. The objective of the present study was to compare the effects of standard-dose epinephrine with balloon occlusion of the descending aorta on cortical cerebral blood flow augmentation during CPR. Ventricular fibrillation was induced in 24 anaesthetised piglets. A non-intervention interval of 9 min was followed by open-chest CPR. The animals were randomised to receive repeated intravenous bolus doses of epinephrine 20 microg/kg or balloon occlusion of the descending aorta. Focal cortical cerebral blood flow was measured continuously using laser-Doppler flowmetry. Balloon occlusion of the aorta resulted in a significantly higher mean cortical cerebral blood flow and a lower cerebral oxygen extraction ratio than epinephrine during CPR. After restoration of spontaneous circulation the cerebral perfusion appeared compromised to the same extent in both groups, with lower blood flow compared to baseline, high cerebral oxygen extraction and cerebral tissue acidosis. No difference in cerebral cortical vascular resistance between the two groups could be detected. It is concluded that aortic balloon occlusion was superior to epinephrine in cerebral blood flow augmentation during resuscitation and did not generate adverse effects on cerebral blood flow, oxygenation or tissue pH after restoration of spontaneous circulation. No evidence of cerebral vasoconstriction induced by standard-dose epinephrine was found.

Differences in the pharmacodynamics of epinephrine and vasopressin during and after experimental cardiopulmonary resuscitation

Vasopressin has been investigated as a possible alternative to epinephrine during cardiopulmonary resuscitation (CPR). We tested the hypothesis that vasopressin, in comparison with epinephrine, would improve cerebral blood flow and metabolism during CPR as well as after restoration of spontaneous circulation (ROSC). A total of 22 anaesthetised piglets were subjected to 5 min of ventricular fibrillation followed by 8 min of closed-chest CPR. The piglets were randomly allocated to receive repeated boluses of either 45 microg/kg epinephrine or 0.4 U/kg vasopressin IV. Haemodynamic parameters, cerebral cortical blood flow and cerebral tissue pH and PCO(2) were continuously monitored during CPR and up to 4 h after ROSC. Cerebral oxygen extraction ratio was calculated. Cerebral cortical blood flow increased transiently after each bolus of epinephrine, while only the first bolus of vasopressin resulted in a sustained increase. The peak in cerebral cortical blood flow was reached approximately 30 s later with vasopressin. During the initial 5 min following ROSC, cerebral cortical blood flow was greater in the vasopressin group. In conclusion, there is a difference between epinephrine and vasopressin in the time from injection to maximal clinical response and the duration of their effect, but their overall effects on blood pressures and cerebral perfusion do not differ significantly during CPR. In contrast, vasopressin results in a greater cerebral cortical blood flow during a transient period after ROSC.

High dose versus standard dose epinephrine in cardiac arrest - a meta-analysis

In the management of cardiac arrest there is ongoing controversy concerning the optimal dose of epinephrine. To obtain the best available evidence regarding the current optimal dose, we performed a meta-analysis. We searched the Medline database online and reviewed citations in relevant articles to identify studies that met preset inclusion criteria (prospective, randomized, double-blind). Five trials were identified. The pooled odds ratio for return of spontaneous circulation favours the experimental dose. The pooled odds ratio for hospital discharge failed to demonstrate a statistically significant beneficial effect of high and/or escalating doses of epinephrine in comparison with standard dose of epinephrine. The possibility that patients who have already sustained irreversible neurologic injury will be resuscitated carries potential adverse social and economic implications.

Paramedic activities, drug administration and survival from out of hospital cardiac arrest

OBJECTIVE

To examine the impact of administration of cardioactive drugs on the outcome from out of hospital cardiac arrest.

DESIGN

Longitudinal observational cohort study with historical controls before and after the introduction of drug use in cardiac arrest by paramedics.

SUBJECTS

Adult patients who had sustained an out of hospital cardiac arrest of cardiac aetiology and were treated by paramedics.

SETTING

Edinburgh, Scotland.

OUTCOME MEASURES

Return of spontaneous circulation, admission to and discharge from hospital.

RESULTS

There was no significant difference in the demographics between Period 1 (prior to drug administration) and Period 2 (after). There was no difference in outcome between Period 1 and Period 2 for all three parameters, return of spontaneous output 30.1 versus 35%, admission to hospital 18.9 versus 24.5% and discharge 5.8 versus 6.5%. If the presenting rhythm of VF/pulseless VT alone was considered survival to hospital discharge was 12.1% in Period 1 and 10.3% in Period 2.

CONCLUSION

The addition of cardioactive drug administration to the treatment of out of hospital cardiac arrest does not improve survival.

Paramedics, technicians, and survival from out of hospital cardiac arrest

OBJECTIVE

To test the hypothesis that limited paramedic advanced life support skills afford no advantage in survival from cardiac arrest when compared with non-paramedic ambulance crews equipped with defibrillators in an urban environment; and to investigate whether separate response units delayed on scene times.

METHODS

A prospective, observational study was conducted over 17 consecutive months on all adult patients brought to the accident and emergency (A&E) department of Glasgow Royal Infirmary having suffered an out of hospital cardiac arrest of cardiac aetiology. The main interventions were bystander cardiopulmonary resuscitation (CPR) and limited advance life support skills.

MAIN OUTCOME MEASURES

Return of spontaneous circulation, survival to admission, and discharge.

RESULTS

Of 240 patients brought to the A&E department, 19 had no clear record of whether a paramedic was or was not involved and so were excluded. There was no difference in survival between the two groups, although a trend to admission favoured non-paramedics. Paramedics spent much longer at the scene (P < 0.0001). Witnessed arrests (P = 0.01), early bystander CPR (P = 0.12), shockable rhythms (P = 0.003), and defibrillation (P < 0.0001) were associated with better survival. Intubation and at scene times were not associated with better survival. Delayed second response units did not prolong at scene times.

CONCLUSIONS

The interventions of greatest benefit in out of hospital cardiac arrest are basic life support and defibrillation. Additional skills are of questionable benefit and may detract from those of greatest benefit.