Endotracheal epinephrine is unreliable

Effects of Endotracheal Epinephrine on Pharmacokinetics and Survival in a Swine Pediatric Cardiac Arrest Model

OBJECTIVES

The aim of this study was to compare the endotracheal tube (ET) and intravenous (IV) administration of epinephrine relative to concentration maximum, time to maximum concentration, mean concentration over time (MC), area under the curve, odds, and time to return of spontaneous circulation (ROSC) in a normovolemic pediatric cardiac arrest model.

METHODS

Male swine weighing 24-37 kg were assigned to 4 groups: ET (n = 8), IV (n = 7), cardiopulmonary resuscitation (CPR) + defibrillation (CPR + Defib) (n = 5), and CPR only (n = 3). Swine were placed arrest for 2 minutes, and then CPR was initiated for 2 minutes. Epinephrine (0.1 mg/kg) for the ET group or 0.01 mg/kg for the IV was administered every 4 minutes or until ROSC. Defibrillation started at 3 minutes and continued every 2 minutes for 30 minutes or until ROSC for all groups except the CPR-only group. Blood samples were collected over a period of 5 minutes.

RESULTS

The MC of plasma epinephrine for the IV group was significantly higher at the 30- and 60-second time points (P = 0.001). The ET group had a significantly higher MC of epinephrine at the 180- and 240-second time points (P < 0.05). The concentration maximum of plasma epinephrine was significantly lower for the ET group (195 ± 32 ng/mL) than for the IV group (428 ± 38 ng/mL) (P = 0.01). The time to maximum concentration was significantly longer for the ET group (145 ± 26 seconds) than for the IV group (42 ± 16 seconds) (P = 0.01). No significant difference existed in area under the curve between the 2 groups (P = 0.62). The odds of ROSC were 7.7 times greater for the ET versus IV group. Time to ROSC was not significantly different among the IV, ET, and CPR + Defib groups (P = 0.31).

CONCLUSIONS

Based on the results of this study, the ET route of administration should be considered a first-line intervention.

Endotracheal Administered Epinephrine Is Effective in Return of Spontaneous Circulation Within a Pediatric Swine Hypovolemic Cardiac Arrest Model

OBJECTIVE

Early administration of epinephrine increases the incidence of return of spontaneous circulation (ROSC) and improves outcomes among pediatric cardiac arrest victims. Rapid endotracheal (ET) intubation can facilitate early administration of epinephrine to pediatric victims. To date, no studies have evaluated the use of ET epinephrine in a pediatric hypovolemic cardiac arrest model to determine the incidence of ROSC.

METHODS

This prospective, experimental study evaluated the pharmacokinetics and/or incidence of ROSC following ET administered epinephrine and compared it to these experimental groups: intravenous (IV) administered epinephrine, cardiopulmonary resuscitation only (CPR), and CPR + defibrillation (CPR + Defib).

RESULTS

Endotracheal administered epinephrine, at the Pediatric Advanced Life Support (PALS) recommended dose, was not significantly different than IV administered epinephrine in maximum plasma concentrations, time to maximum plasma concentration, area under the curve, or ROSC, or mean plasma concentrations at various time points (P > 0.05). The odds of ROSC in the ET group were 2.4 times greater than the IV group. The onset to ROSC in the ET group was significantly shorter than the IV group (P < 0.0001).

CONCLUSIONS

These data support that ET epinephrine administration remains an alternative to IV administered epinephrine and faster at restoring ROSC among pediatric hypovolemic cardiac arrest victims in the acute setting when an endotracheal tube is present. Although further research is required to determine long-term outcomes of high-dose ET epinephrine administration, these data reinforce the therapeutic potential of ET administration of epinephrine to restore ROSC before IV access.

Pharmacokinetic effects of endotracheal, intraosseous, and intravenous epinephrine in a swine model of traumatic cardiac arrest

INTRODUCTION

Limited prospective data exist regarding epinephrine's controversial role in managing traumatic cardiac arrest (TCA). This study compared the maximum concentration (Cmax), time to maximum concentration (Tmax), plasma concentration over time, return of spontaneous circulation (ROSC), time to ROSC, and odds of ROSC of epinephrine administered by the endotracheal (ETT), intraosseous (IO), and intravenous (IV) routes in a swine TCA model.

METHODS

Forty-nine Yorkshire-cross swine were assigned to seven groups: ETT, tibial IO (TIO), sternal IO (SIO), humeral IO (HIO), IV, CPR with defibrillation (CPRD), and CPR only. Swine were exsanguinated 31% of their blood volume and cardiac arrest induced. Chest compressions began 2 min post-arrest. At 4 min post-arrest, 1 mg epinephrine was administered, and blood specimens collected over 4 min. Resuscitation continued until ROSC or 30 min elapsed.

RESULTS

The Cmax of IV epinephrine was significantly higher than the TIO group (P = 0.049). No other differences in Cmax, Tmax, ROSC, and time to ROSC existed between the epinephrine groups (P > 0.05). Epinephrine levels were detectable in two of seven ETT swine. No significant difference in ROSC existed between the epinephrine groups and CPRD group (P > 0.05). Significant differences in ROSC existed between all groups and the CPR only group (P < 0.05). No significant differences in odds of ROSC were noted.

CONCLUSIONS

The pharmacokinetics of IV, HIO, and SIO epinephrine were comparable. Endotracheal epinephrine absorption was highly variable and unreliable compared to IV and IO epinephrine. Epinephrine appeared to have a lesser role than volume replacement in resuscitating TCA.

[Intraosseous infusion in the pediatric emergency medical service. Analysis of emergency medical missions 1990-2009]

BACKGROUND

Timely establishment of venous access in infants and toddlers during emergency medical care can be a particularly challenging task. Alternative routes for drug and fluid administration, such as endobronchial, intramuscular, central venous or venous cut-down do not offer reliable solutions. Intraosseous infusion (IOI) has become established as an effective alternative intravascular access for rapid and efficient drug delivery. IOI was introduced in our local emergency medical service (EMS) in 1993 and was assigned a high priority in international guidelines for pediatric emergency medical care in 2000 and 2005. The aim of this study was to review the impact of the introduction of IOI on drug administration routes during prehospital emergency treatment of critically ill or severely injured pediatric patients (NACA index V-VII) in our tertiary medical care centre over a period of 20 years.

METHODS

Pediatric prehospital emergency medical protocols from 1990 to 2009 were analyzed with respect to the administration routes for fluids and medications in severely injured or critically ill children with NACA severity scores V-VII. The frequency and mode of vascular access during prehospital treatment including IOI, endobronchial administration, central venous catheterization (CVC) and intramuscular administration as well as prehospital treatment and transportation without vascular access were analyzed. Two groups were compared: the introduction phase of IOI between 1990 and 1999 and the phase of growing IOI routine after introducing guidelines and regular staff IOI technique training between 2000 and 2009. Demographic data and drug administration routes in the two different time periods were analyzed using the Mann-Whitney-u test and t-test or χ(2)-test, respectively. A p-value <0.05 was regarded as significant.

RESULTS

A total of 5,279 pediatric prehospital emergency charts were analyzed and 401 patients (7.6%) were scored as NACA V-VII. At the emergency scene 299 patients (75%) received a peripheral intravenous access, 3 (0.7%) a central venous line access, 77 (19%) an intraosseous needle and in 22 (5.4%) no vascular or intraosseous access was used during the course of prehospital treatment (NACA VII - 13 patients, NACA VI - 2 patients, NACA V - 7 patients). Of the NACA VII patients 3 were transported under continuous cardiopulmonary resuscitation without vascular access. After 2002 all patients with NACA index VII were treated with vascular or intraosseous access. In 48 patients (12%) at least initial medication was given by the endobronchial or alternative route but within the last 3 years endobronchial drug administration was no longer reported. Thus, in 124 critically ill patients (31%) routine peripheral venous access could not be established initially or until the end of treatment (77 times IOI, 22 times no access over the course of treatment, 3 times CVC and 22 times initial endobronchial followed by peripheral venous access). Over the reviewed period the use of IOI increased significantly (p<0.001), while the incidence of lacking vascular access (p<0.05) and alternative drug administration routes (p<0.001) continuously decreased.

CONCLUSION

The IOI technique has not only been assigned a high priority in the guidelines for pediatric emergency care of critically ill children with difficult or failed venous access but has also significantly influenced current prehospital care. The introduction of the IOI technique in our prehospital pediatric emergency system has markedly reduced the number of critically ill or severely injured pediatric patients without vascular access or with less reliable alternative administration routes in the last 20 years.

Part 10: Pediatric basic and advanced life support: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

Note From the Writing Group: Throughout this article, the reader will notice combinations of superscripted letters and numbers (eg, “Family Presence During ResuscitationPeds-003”). These callouts are hyperlinked to evidence-based worksheets, which were used in the development of this article. An appendix of worksheets, applicable to this article, is located at the end of the text. The worksheets are available in PDF format and are open access.

The role of resuscitation drugs and placental transfusion in the delivery room management of newborn infants

Medications are used rarely in newborn resuscitations and are probably justifiable in less than 0.1% of births. Doses used are mainly extrapolated from animal and adult data. Despite this, the drugs used, their order and route of administration have all been sources of controversy for many years. There have been polarised views, often focusing upon adrenaline and sodium bicarbonate and more recently new drugs such as vasopressin have been suggested, once again extrapolating from adult experience. This article examines the sparse data behind the use of any medication at birth and the poor outcome data available. The appropriate decline in the indiscriminate use of volume expansion is considered and balanced by the increasing evidence in favour of delayed clamping of the umbilical cord. Focusing on the basic steps of resuscitation, improving the quality of their application and avoiding relative hypovolaemia, must improve the quality of outcome data. The place of medications in newborn resuscitation should be regarded as experimental and still requires evidence to justify their use especially in premature babies.

Use and efficacy of endotracheal versus intravenous epinephrine during neonatal cardiopulmonary resuscitation in the delivery room

OBJECTIVE

Given the paucity of information regarding endotracheal epinephrine for newborn resuscitation, the objectives of this study were: (1) to determine the frequency of endotracheal epinephrine use in newborns in the delivery room, and (2) to determine whether the previously recommended dose of 0.01 to 0.03 mg/kg of endotracheal epinephrine is effective in establishing a return of spontaneous circulation.

PATIENTS AND METHODS

A retrospective review was conducted for all neonates who received > or = 1 dose of epinephrine in the delivery room between January 1999 and December 2004. Infants who received > or = 1 dose of endotracheal epinephrine in the delivery room during resuscitation were included in the study population whether or not they survived to be admitted to the NICU. Exclusion criteria included lethal congenital anomalies, delivery outside the hospital, and missing medical charts.

RESULTS

Of 93,656 infants, 52 neonates (0.06%) received epinephrine in the delivery room, 5 of whom met exclusion criteria. Of the remaining 47 infants, 44 (94%) received the first dose via the endotracheal tube. Only 14 (32%) of 44 achieved return of spontaneous circulation after endotracheal tube administration of epinephrine. Of the 30 remaining infants, 23 (77%) had return of spontaneous circulation with intravenous epinephrine after initially failing endotracheal tube epinephrine. There were no differences in clinical characteristics between newborns who responded to endotracheal tube versus intravenous epinephrine except for a lower blood glucose on NICU admission (52 vs 113 mg%).

CONCLUSIONS

Endotracheal epinephrine is frequently used when intensive resuscitation is required in the delivery room. The previously recommended endotracheal epinephrine dose of 0.01 to 0.03 mg/kg is often ineffective. Higher endotracheal doses will likely be needed to improve efficacy. A prospective study is needed to determine the best endotracheal epinephrine dosing regimen. Until such information is available, intravenous administration should be the preferred route of delivery.

Endotracheal delivery of medications during neonatal resuscitation

If the endotracheal route is to be used for administration of epinephrine, the limited available evidence suggests that the currently recommended dose of 0.01 mg/kg is likely to be too low to be effective. Given the paucity of high-quality clinical data regarding endotracheal epinephrine, the intravenous route should be used as soon as venous access is established. Given the complete lack of clinical data in newborns, endotracheal administration of naloxone is not recommended.

Endobronchial adrenaline: should it be reconsidered? Dose response and haemodynamic effect in dogs

BACKGROUND

Tracheal drug administration is a route for drug delivery during cardiopulmonary resuscitation when intravenous access is not immediately available. However, tracheal adrenaline (epinephrine) injection has been recently shown to be associated with detrimental decrease in blood pressure. This was attributed to exaggerated early beta2 mediated effects unopposed by alpha-adrenergic vasoconstriction. We hypothesized that endobronchial adrenaline administration is associated with better drug absorption, which may abolish the deleterious drop of blood pressure associated with tracheal drug administration.

OBJECTIVE

To determine haemodynamic variables after endobronchial adrenaline administration in a non-arrest canine model.

DESIGN

Prospective, randomized, laboratory study.

METHODS

Adrenaline (0.02, 0.05, 0.1 mg/kg) diluted with normal saline was injected into the bronchial tree of five anaesthetized dogs. Injection of 10-ml saline served as control. Heart rate, blood pressure and arterial blood gases were monitored for 60 min after drug instillation. The protocol was repeated after 1 week.

RESULTS

Adrenaline at a dose of 0.02 mg/kg produced only a minor initial decrease in diastolic (from 90 +/- 5 to 78 +/- 3 mmHg, P=0.05), and mean blood pressure (from 107 +/- 4 to 100 +/- 3 mmHg, P=0.05), in all dogs. This effect lasted less then 30 s following the drug administration. In contrast, higher adrenaline doses (0.05 and 0.1 mg/kg) produced an immediate increase in diastolic (from 90 +/- 5 to 120 +/- 7 mmHg; and from 90 +/- 5 to 170 +/- 6 mmHg, respectively), and mean blood pressure (from 107 +/- 4 to 155 +/- 10 mmHg; and from 107 +/- 4 to 219 +/- 6 mmHg, respectively). All adrenaline doses resulted in an immediate increase in systolic blood pressure and pulse. Endobronchial administration of saline (control) affected none of the haemodynamic variables.

CONCLUSIONS

In a non-arrest model, endobronchial adrenaline administration, as opposed to the effect of tracheal adrenaline, produced only a minor decrease in diastolic and mean blood pressure. We suggest that endobronchial adrenaline administration should be investigated further in a CPR low-flow model when maintaining adequate diastolic pressure may be crucial for survival.

Should vasopressin replace adrenaline for endotracheal drug administration?

OBJECTIVE

Arginine vasopressin was established recently as a drug of choice in the treatment of cardiac arrest and in retractable ventricular fibrillation; however, the hemodynamic effect of vasopressin following endotracheal drug administration has not been fully elucidated. We compared the effects of endotracheally administered vasopressin vs. adrenaline on hemodynamic variables in a canine model, and we investigated whether vasopressin produces the same deleterious immediate blood pressure decrease as did endotracheal adrenaline in the canine model.

DESIGN

Prospective controlled study.

SETTING

Animal laboratory in Tel-Aviv University, Israel.

SUBJECTS

Five adult mongrel dogs weighing 6.5-20 kg.

INTERVENTIONS

Dogs were anesthetized; each dog was intubated orally, and both femoral arteries were cannulated for the measurement of arterial pressure and for sampling blood gases. Each dog was studied four times, 1 wk apart, by using the same protocol for injection and anesthesia: endotracheal placebo (10 mL NaCl 0.9%,), endotracheal vasopressin (1 units/kg), endobronchial adrenaline (0.1 mg/kg), and endotracheal adrenaline (0.1 mg/kg). Following placebo, vasopressin, and adrenaline instillation, five forced manual ventilations were delivered with an Ambu bag. Each dog was its own control.

MEASUREMENTS AND MAIN RESULTS

Following placebo or drug administration, heart electrocardiography and arterial pressures were continuously monitored with a polygraph recorder for 1 hr. Endotracheal vasopressin produced an immediate increase of diastolic blood pressure (from 83 +/- 10 mm Hg [baseline] to 110 +/- 5 mm Hg at 1 min postinjection). This response lasted >1 hr. In contrast, both endotracheal and endobronchial administration of adrenaline produced an early and significant (p <.05) decrease in diastolic and mean blood pressures. The diastolic blood pressure increase from 85 +/- 10 mm Hg to 110 +/- 10 mm Hg took an ill-afforded 55 secs following endotracheal adrenaline. Diastolic blood pressure was significantly (p <.05) higher following vasopressin compared with adrenaline administration in both routes.

CONCLUSIONS

Vasopressin accomplishes its hemodynamic effect, particularly on diastolic blood pressure, more rapidly, vigorously, and protractedly and to a significant degree compared with both endotracheal and endobronchial adrenaline. Evaluation of the effects of endotracheal vasopressin in a closed chest cardiopulmonary resuscitation model is recommended.

Epinephrine for the resuscitation of apparently stillborn or extremely bradycardic newborn infants

BACKGROUND

Epinephrine is a cardiac stimulant with complex effects on the heart and blood vessels. It has been used for decades in all age groups to treat cardiac arrest and bradycardia. Despite formal guidelines for the use of epinephrine in neonatal resuscitation, the evidence for these recommendations has not yet been rigorously scrutinised. While it is understood that this evidence is in large part derived from animal models and the adult human population, the contribution from work in the neonatal population remains unclear. In particular, it remains to be determined if any randomised studies in neonates have helped to establish if the administration of epinephrine in the context of apparent stillbirth or extreme bradycardia might influence mortality and morbidity.

PRIMARY OBJECTIVE

~bullet~To determine if the administration of epinephrine to apparently stillborn and extremely bradycardic newborns reduces mortality and morbidity Secondary objectives: ~bullet~To determine the effect of intravenous versus endotracheal administration on mortality and morbidity ~bullet~To determine the effect of high dose versus standard dose epinephrine on mortality and morbidity, where high dose is defined as any dose greater than the current recommended standard dose of 0.1 to 0.3ml/kg of a 1:10,000 solution of epinephrine ~bullet~To determine whether the effect of epinephrine on mortality and morbidity varies with gestational age, i.e. term (greater than or equal to 37 weeks) versus pre-term (less than 37 weeks)

SEARCH STRATEGY

Searches were made of Medline from 1966 to December 2002, CINAHL (from 1982), Current Contents (from 1988), EMBASE, and the Cochrane Controlled Trials Register (2002, issue 4). Bibliographies of conference proceedings were reviewed and unpublished studies were sought by hand searching the conference proceedings of the Society for Pediatric Research and the European Society for Pediatric Research from 1993 to 2002.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of newborns, both pre-term and term, receiving epinephrine for unexpected apparent stillbirth or extreme bradycardia.

DATA COLLECTION AND ANALYSIS

No studies were found meeting the criteria for inclusion in this review

MAIN RESULTS

No studies were found meeting the criteria for inclusion in this review.

REVIEWER'S CONCLUSIONS

We found no randomised, controlled trials evaluating the administration of epinephrine to the apparently stillborn or extremely bradycardic newborn infant. Similarly, we found no randomised, controlled trials which addressed the issues of optimum dosage and route of administration of epinephrine. Current recommendations for the use of epinephrine in newborn infants are based only on evidence derived from animal models and the human adult literature. Randomised trials in neonates are urgently required to determine the role of epinephrine in this population.

Endotracheal epinephrine: a call for larger doses

Endotracheal administration of epinephrine 0.02 mg/kg (twice the IV dose) is recommended when IV access is unavailable during cardiopulmonary resuscitation. The standard IV dose has been considered too small for the endotracheal route by causing a detrimental decrease of arterial blood pressure (BP), presumably mediated by the beta-adrenergic receptor unopposed by alpha adrenergic vasoconstriction. We conducted a prospective, randomized, laboratory comparison of increasing doses of endotracheal epinephrine to ascertain the yet undetermined optimal dose of endotracheal epinephrine that would increase BP. After injecting normal saline (control), saline-diluted epinephrine (0.02, 0.035, 0.1, 0.2, and 0.3 mg/kg) was injected into the endotracheal tube of five anesthetized dogs at least 1 wk apart. Arterial blood samples for blood gases were collected before and at 14 time points up to 60 min after the drug administration. Heart rate and arterial BP were continuously monitored with a polygraph recorder. Only the 0.3 mg/kg dose successfully caused an increase in BP, observed 2 min after administration, and lasting for 10 min. An early decrease in BP was obviated only at a dose equivalent to 10-fold the currently recommended one.

IMPLICATIONS

We conducted a prospective, randomized, laboratory comparison of increasing doses of endotracheal epinephrine to ascertain the yet undetermined optimal dose of endotracheal epinephrine that would increase arterial blood pressure (BP). A decrease in BP was obviated only at a dose equivalent to 10-fold the currently recommended one. Clinical studies using larger doses of endotracheal epinephrine and their use as first-line therapy in cardiac arrest are warranted.

Comparison of epinephrine with vasopressin on bone marrow blood flow in an animal model of hypovolemic shock and subsequent cardiac arrest

OBJECTIVE

The intraosseous route is an emergency alternative for the administration of drugs and fluids if vascular access cannot be established. However, in hemorrhagic shock or after vasopressors are given during resuscitation, bone marrow blood flow may be decreased, thus impairing absorption of intraosseously administered drugs. In this study, we evaluated the effects of vasopressin vs. high-dose epinephrine in hemorrhagic shock and cardiac arrest on bone marrow blood flow.

DESIGN

Prospective, randomized laboratory investigation that used an established porcine model for measurement of hemodynamic variables and organ blood flow.

SETTING

University hospital laboratory.

SUBJECTS

Fourteen pigs weighing 30 +/- 3 kg.

INTERVENTIONS

Radiolabeled microspheres were injected to measure bone marrow blood flow during a prearrest control period and during hypovolemic shock produced by rapid hemorrhage of 35% of the estimated blood volume. In the second part of the study, ventricular fibrillation was induced; after 4 mins of untreated cardiac arrest and 4 mins of standard cardiopulmonary resuscitation, a bolus dose of either 200 microg/kg epinephrine (n = 6) or 0.8 units/kg vasopressin (n = 6) was administered. Defibrillation was attempted 2.5 mins after drug administration, and blood flow was assessed again at 5 and 30 mins after successful resuscitation.

MEASUREMENTS AND MAIN RESULTS

Mean +/- sem bone marrow blood flow decreased significantly during induction of hemorrhagic shock from 14.4 +/- 4.1 to 3.7 +/- 1.8 mL.100 g-1.min-1 in the vasopressin group and from 18.2 +/- 4.0 to 5.2 +/- 1.0 mL.100 g-1.min-1 in the epinephrine group (p =.025 in both groups). Five minutes after return of spontaneous circulation, mean +/- sem bone marrow blood flow was 3.4 +/- 1.1 mL.100 g-1.min-1 after vasopressin and 0.1 +/- 0.03 mL.100 g-1.min-1 after epinephrine (p =.004 for vasopressin vs. epinephrine). At the same time, bone vascular resistance was significantly (p =.004) higher in the epinephrine group when compared with vasopressin (1455 +/- 392 vs. 43 +/- 19 mm Hg. mL-1.100 g.min, respectively).

CONCLUSIONS

Bone blood flow responds actively to both the physiologic stress response of hemorrhagic shock and vasopressors given during resuscitation after hypovolemic cardiac arrest. In this regard, bone marrow blood flow after successful resuscitation was nearly absent after high-dose epinephrine but was maintained after high-dose vasopressin. These findings emphasize the need for pressurized intraosseous infusion techniques, because bone marrow blood flow may not be predictable during hemorrhagic shock and drug therapy.

Is endotracheal adrenaline deleterious because of the beta adrenergic effect?

IV adrenaline increases coronary and cerebral perfusion pressures during cardiopulmonary resuscitation. We recently showed that endotracheal adrenaline can decrease blood pressure (BP), a detrimental effect presumably mediated by the beta 2-adrenergic receptor unopposed by alpha-adrenergic vasoconstriction. This prospective, randomized, laboratory comparison of endotracheal adrenaline (0.05 mg/kg diluted with normal saline to 10 mL total volume) with or without nonselective beta-blocker (propranolol) pretreatment was conducted in an attempt to clarify the mechanism of this BP decrease. Five mongrel dogs were given 0.05 mg/kg endotracheal adrenaline (diluted) or 0.05 mg/kg endotracheal adrenaline followed by an IV propranolol (0.1 mg/kg) pretreatment. Each dog served as its own control (10 mL of normal saline administered endotracheally) and received each regimen at least one week apart. Endotracheal adrenaline given after the propranolol pretreatment produced an increase in systolic, diastolic, and mean arterial BPs, from 165/110 mm Hg (mean 128 mm Hg) to 177.5/125 mm Hg (mean 142.5 mm Hg), respectively, as opposed to the hypotensive effect of isolated endotracheal adrenaline (P < 0.03). Thus, endotracheal adrenaline was associated with predominantly beta-adrenergic-mediated effects, causing hypotension via peripheral vasodilatation unopposed by alpha-adrenergic vasoconstriction. The search for the optimal dose of endotracheal adrenaline should be aimed at achieving the higher alpha-adrenergic vasoconstrictive threshold.

Medications during resuscitation -- what is the evidence?

Medication use during neonatal resuscitation is uncommon. The infrequent use of resuscitation medications has impeded rigorous investigations to determine the most effective agents and/or dosing regimens. The medications most commonly used during delivery room resuscitation include epinephrine, sodium bicarbonate, naloxone hydrochloride and volume expanders. The available evidence for each of these medications is reviewed in this article.

Pediatric resuscitation outside the operating room

Protocols regarding the treatment of cardiac arrest of the pediatric patient outside the operating room are continually being reviewed as knowledge regarding the pathophysiology of cardiac arrest and the pharmacologic properties of resuscitative drugs has progressed. The indications for treatment of cardiac arrest by the various resuscitative drugs, and techniques for obtaining access for the administration of these drugs are discussed.

Corpus cavernosum as an alternative means of intravenous access in the emergency setting

BACKGROUND

The present study was designed to investigate the feasibility of using the corpus cavernosum as an alternative means of intravenous access in the emergency setting.

METHODS

The feasibility of achieving the infusion flow rates was first ascertained using direct intracavernous infusion of normal saline. The effect of atropine and adrenaline when given via this route was then studied. Hypovolaemic shock was then induced in dogs who were then actively resuscitated via this route using normal saline, Haemaccel and whole blood.

RESULTS

Infusion flow rates were achieved for normal saline of 32.3, 50.3 and 67.3 mL per min at 100, 200 and 300 mmHg pressure, respectively. The peak effects of atropine and adrenaline via this route were seen at approximately 1 min after injection. Resuscitation using this method was uniformly successful in all dogs via the corpus cavernosum, with all reaching or exceeding their premorbid central venous pressure (CVP), and approaching or reaching their premorbid mean arterial pressure (MAP). In comparison the control dog's CVP and MAP did not rise during the period of observation after it was bled.

CONCLUSIONS

The corpus cavernosum is a practical alternative means of intravenous access in the emergency setting in the dog model.

Comparison of intravenous and endotracheal epinephrine during cardiopulmonary resuscitation in newborn piglets

OBJECTIVE

To compare the efficacy of intravenous and endotracheal epinephrine administration, and intravenous administration above and below the diaphragm, during cardiopulmonary resuscitation in newborn piglets.

DESIGN

Prospective, randomized, experimental laboratory protocol.

SETTING

Perinatal cardiovascular research laboratory at a university school of medicine.

SUBJECTS

Forty newborn piglets (Sus domesticus).

INTERVENTIONS

After cardiac arrest by ventricular fibrillation, cardiopulmonary resuscitation was begun. Radiolabeled epinephrine or placebo (0.9% sodium chloride) was administered into the right atrium, femoral vein, or endotracheal tube. Chest compressions and ventilation were continued for 10 mins.

MEASUREMENTS AND MAIN RESULTS

After epinephrine or placebo administration, samples were obtained from the systemic arterial circulation for measurement of radioisotope activity and plasma epinephrine concentrations. Mean carotid arterial blood pressure, right atrial, and inferior vena caval pressures were measured continuously. Epinephrine administration via the right atrium and femoral vein resulted in significant increases in plasma epinephrine concentration, percent of radioisotope recovery, and mean carotid arterial blood pressure, whereas endotracheal epinephrine administration did not. Placebo administered into the femoral vein resulted in a significant increase in percent radioisotope recovery, but not in plasma epinephrine concentration or carotid arterial blood pressure. Endotracheal administration of placebo did not result in significant increases in plasma epinephrine concentration, percent radioisotope recovery, or carotid arterial blood pressure. There were no significant differences between right atrial or inferior vena caval pressures among the groups.

CONCLUSIONS

During cardiopulmonary resuscitation in newborn piglets, intravenous administration of epinephrine is more efficacious than endotracheal administration. Furthermore, efficacy is similar between femoral venous and right atrial administration.

The time required to perform different methods for endotracheal drug administration during CPR

We compared the times necessary to perform different endotracheal drug application techniques during CPR. In a simulated CPR situation with a mannequin 28 paramedics and seven emergency physicians performed different drug instillation techniques in a randomized manner: direct injection into the upper end of the endotracheal tube (group tube), via a suction catheter placed into the bronchial system (group suction catheter), via a flexible venous catheter placed into the bronchial system (group venous catheter), using an EDGAR tube (an endotracheal tube with an injection channel within the wall of the tube (group EDGAR). We measured the time necessary to prepare the drug solution and compared the time necessary to prepare and perform each instillation method and the time the ventilation was interrupted. Comparison between groups was performed by the Kruskal-Wallis test. It took significantly longer to perform the more complicated techniques using suction catheters (26; 18 54 s) and venous catheters (30; 22-50 s) compared to the other two groups (median; min-max) (p < 0.05). No differences concerning the application time were found between the group tube (7; 5 14 s) and group EDGAR (8; 5-13 s). The time of interruption of chest compression's and ventilation: group suction tube (11; 5-19 s) and group catheter (12; 6-18 s) was significant longer than in group tube (5; 2-9 s) (p < 0.05). In group EDGAR the connection ventilator-tube remained intact due to its concept of drug application. The use of special devices such as suction catheters or venous catheters for endotracheal instillation during CPR results in significantly longer preparation and instillation times with a longer interruption of the oxygen supply and chest compression's.

Plasma catecholamine levels following tracheal and intravenous epinephrine administration in swine

We compared plasma epinephrine levels after three different tracheal epinephrine application techniques and intravenous injection in male and female anesthetized and paralyzed domestic pigs. Epinephrine was administered intravenously (10 microg/kg) (group i.v.) or tracheally (100 microg/kg) either by direct injection into the upper end of the tracheal tube (group Tube), via a suction tube placed into the bronchial system (group Catheter) or using an EDGAR tube (group EDGAR), each group: n = 8. Arterial plasma samples were drawn before and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7 and 10 min after epinephrine administration. Plasma concentrations of epinephrine were measured with high pressure liquid chromatography using electrochemical detection. Analysis was performed by regression analysis for correlated data. Total plasma epinephrine concentrations showed a significant increase within 0.5 min in all groups. However, peak plasma epinephrine levels in group i.v. were significantly higher than in tracheal groups, while no differences between tracheal groups over the time were found. We conclude that in swine with spontaneous circulation tracheal instillation techniques using special devices such as suction tubes or EDGAR tubes result in onset and peak plasma epinephrine levels equivalent to those after direct injection into the upper end of the tracheal tube.

Hemodynamic effects of tracheal and intravenous adrenaline in infants with congenital heart anomalies

BACKGROUND

If intravenous access cannot be accomplished during cardiopulmonary resuscitation in children, tracheal administration of 100 micrograms/kg of adrenaline (ten times greater than the intravenous dose) is recommended.

METHODS

In a randomized crossover study we recoreded the hemodynamic effect of a low dose of intravenous adrenaline and a ten times greater tracheal dose. While anesthetized for open heart surgery, fourteen infants received one dose of adrenaline intravenously (0.3 microgram/kg) and the other tracheally (3 micrograms/kg).

RESULTS

During the first 5 minutes after administration mean arterial pressure (MAP) and heart rate (HR) increased after both intravenous and tracheal administration (P < 0.001). The maximum increase in MAP was 28% (17-68%, median and range) after intravenous injection and 20% (6-69%, P < 0.05 when compared to intravenous injection) after tracheal instillation. In four infants, MAP increased less than 10% after tracheal instillation. The maximum increases in MAP and HR occurred 1 min (1-2 min) after intravenous injection and 3 min (2-4 min) after tracheal instillation (P < 0.001).

CONCLUSION

Tracheal administration 3 micrograms/kg adrenaline increased mean arterial blood pressure in infants with congenital cardiac anomalies, but the increase occurred later and was less consistent than after 0.3 microgram/kg of adrenaline given intravenously.

The use of high doses of adrenaline in paediatric cardiac resuscitation

Adrenaline has been used in cardiac resuscitation for many years, yet until recently its mechanism of action and optimal dosage remained poorly investigated or understood. Recent guidelines suggest the use of higher doses of adrenaline at an early stage in paediatric resuscitation. This paper examines the use of adrenaline in paediatric resuscitation and studies the arguments in favour of using higher doses than previously accepted.

Haemodynamic effects of tracheally administered adrenaline in anaesthetised patients

Ten patients undergoing arterial surgery in the leg received a combined general anaesthetic, which included muscle relaxation and intubation of the trachea, and a regional anaesthetic using a lumbar extradural catheter. The radial arterial pressure was measured. Adrenaline 0.1 micrograms.kg-1 was administered intravenously and the heart rate, arterial pressure and oxygen saturation were recorded every 15 s for 10 min. Adrenaline in 5 ml of saline was given into the trachea at 10 min intervals. The first was saline only, and successive injections contained 0.5 micrograms.kg-1, 1 microgram.kg-1, 2 micrograms.kg-1, and 3 micrograms.kg-1 of adrenaline. The mean maximum rise in systolic arterial pressure after adrenaline given intravenously was 30 (SD 11) mmHg, and 15 (SD 16) mmHg after the maximum dose of adrenaline given into the trachea (p < 0.05). The mean systolic arterial pressure was significantly increased between 45 s and 4.5 min after the adrenaline given intravenously, and 2 min after adrenaline given into the trachea. Of seven patients who received adrenaline 3 micrograms.kg-1 into the trachea, six had no noticeable effect and in the other patient, the increase in arterial pressure was less than 90% of the maximum rise after the adrenaline. We conclude that adrenaline given into the trachea is unreliable in humans with very large doses necessary in some patients to produce a clinically useful haemodynamic effect.

Mastering pediatric cardiopulmonary resuscitation

Premature and unexpected death, especially in children, is tragic and very unacceptable. Effective treatments for sudden death of pediatric patients continue to emerge. Modern cardiopulmonary resuscitation function began with the widespread introduction of closed-chest cardiac massage in 1960; however, despite 35 years of research and refinement, more than 90% of children who receive cardiopulmonary resuscitation do not survive. This article summarizes and expands on current treatment concepts for pediatric sudden death. Emphasis is placed on procedures and techniques that likely are accessible in most medical centers caring for critically ill and injured children.

Emergency alternatives to intravenous access. Intraosseous, intratracheal, sublingual, and other-site drug administration

Difficulties and delays in establishing intravenous access are not uncommon in emergency situations in pediatrics. Alternatives to venous cannulation exist, including intraosseous access, intratracheal drug administration, sublingual and intralingual injection, the intrapenile route, and intracardiac injection. Each of these emergency alternatives to intravenous access is discussed from the historical, technical, utilitarian, and risk-benefit aspects. It is concluded that the intraosseous effective alternative to intravenous access in emergency situations.

Cardiopulmonary resuscitation of the newborn. An update

The abrupt transition from intrauterine to extrauterine life represents a series of profound physiologic changes. This process puts the baby at risk for asphyxia. At birth, the newborn is, therefore, more frequently in need of resuscitation than at any other age. This article reviews the rationale for the sequence and process of neonatal resuscitation, emphasizing recent changes in recommendations.

Epinephrine absorption following endotracheal administration: effects of hypoxia-induced low pulmonary blood flow

To investigate the effects of hypoxia-induced decreased pulmonary blood flow on the trans-pulmonary absorption of epinephrine, we measured pulmonary blood flow and arterial plasma tritium counts per minute following endotracheal [3H]epinephrine administration in six chronically instrumented newborn lambs. The lambs were ventilated alternately with room air and with an hypoxic gas mixture sufficient to decrease pulmonary blood flow to approximately 50% of baseline values. Using this model, we found that hypoxia-induced low pulmonary blood flow did not lead to lower concentrations of epinephrine following endotracheal administration, but rather higher concentrations (P < 0.03). In all six lambs, counts per minute of tritium were higher following administration during low pulmonary blood flow. There was a negative correlation between pulmonary blood flow and arterial plasma tritium counts per minute (r = -0.64, P < 0.03). We conclude that trans-pulmonary absorption of epinephrine is not decreased during times of hypoxia-induced low pulmonary blood flow. These data lend support to the clinical practice of intratracheal epinephrine administration during neonatal resuscitation.

Medications in neonatal resuscitation

Medication usage in neonatal resuscitation has been largely extrapolated from adult resuscitation guidelines. Compared to older children and adults, newborn infants have major anatomical and physiological differences which affect their need for and response to medications during resuscitation. This article discusses some of these differences, highlights the discussion of the Emergency Cardiac Care Panel for Neonatal Pharmacology, lists the recommendations of the panel to the Emergency Cardiac Care Committee, and discusses areas of future research in neonatal resuscitation.

Pediatric resuscitation pharmacology. Members of the Medications in Pediatric Resuscitation Panel

The goal of resuscitation pharmacology is to restart the heart as quickly as possible while preserving vital organ function during chest compression. Unfortunately, the application of advanced life support to pediatric cardiac arrest patients is often unsuccessful. The goal of this paper is to review the scientific rationale and educational considerations used to derive the guidelines for medication use in the pediatric patient during CPR. The first step in drug delivery during CPR is to achieve vascular access. The endotracheal route and intraosseous route may be used, although the former is not reliable. To maximize endotracheal drug effect, a larger dose should be instilled into the airway as deeply as possible. Any vascular access, including intraosseous, is preferable to endotracheal drug administration. Although other alpha-adrenergic agents are theoretically superior, epinephrine remains the drug of choice in pediatric resuscitation. The previously recommended dose, however, may be inadequate; a dose 10 to 20 times larger (100-200 micrograms/kg) should be considered, particularly if the standard dose is ineffective. Lacking convincing data, the indications and dose for calcium are unchanged. Similarly, there are no data advocating a change in the indications or dose for lidocaine, bretylium, or atropine. The treatment of arrest-induced acidosis remains controversial. The mainstay of therapy consists of efforts to maximize oxygenation and tissue perfusion. Bicarbonate is not a first-line drug; its use should be considered when the patient fails to respond to advanced life support efforts, including the administration of high-dose epinephrine. Bicarbonate may be helpful in the postresuscitation setting, but its use should not supplant efforts to maximize tissue perfusion. Adenosine is an effective and generally safe medication for the treatment of supraventricular tachycardia in infants and children. Therefore, its indications, dose, and toxicities should be included in the new guidelines. Finally, a summary of research initiatives are included, including a call for the development of a multi-institutional pediatric clinical resuscitation research group. Large numbers of patients must be enrolled in a standardized manner to better evaluate the benefits and adverse effects of various therapies. This includes the use of high-dose epinephrine, calcium, bicarbonate, and other buffer agents such as Carbicarb and THAM. Animal models simulating the etiology and pathophysiology of pediatric arrest also are needed. In both clinical and animal studies, neurologic outcome and long-term survival should be assessed rather than simply the rate of restoration of spontaneous circulation.

Haemodynamic effects of tracheal compared with intravenous adrenaline

If intravenous access is not available during cardiopulmonary resuscitation, tracheal administration of adrenaline 0.02 mg/kg, twice the intravenous dose, is recommended. In a randomised crossover study we investigated the haemodynamic effects of low doses of tracheal versus intravenous adrenaline. 12 anaesthetised patients having a hip replaced received one dose of adrenaline intravenously (0.1 microgram/kg) and the other tracheally (0.5 microgram/kg). There was a mean increase in systolic arterial pressure of 40.5 mm Hg (range 16-81) after the intravenous injection, with little effect on heart rate. Tracheal adrenaline had no effect on arterial pressure or heart rate. Thus low doses of tracheal adrenaline have no haemodynamic effects. We believe that the recommended tracheal dose of twice the intravenous dose is likely to be ineffective for the treatment of cardiac arrest. Animal studies suggest that a tracheal dose at least ten times the intravenous dose is required.