Download Comparison of Tibial Intraosseous, Sternal Intraosseous

Comparison of Tibial Intraosseous, Sternal
Intraosseous, and Intravenous Routes of
Administration on Pharmacokinetics of
Epinephrine During Cardiac Arrest: A Pilot Study
James Burgert, CRNA, MSNA
Brian Gegel, CRNA, MSN
LTC Michael Loughren, CRNA, PhD, ANC, USA
Thomas Ceremuga, CRNA, PhD, LTC(ret), ANC, USA
Manish Desai, MD
LTC Michael Schlicher, RN, PhD, ANC, USA
COL Joseph O’Sullivan, CRNA, PhD, ANC, USA
COL Paul Lewis, RN, PhD, ANC, USA
Don Johnson, RN, PhD, Col(ret), USAFR, NC
The purpose of this study was to determine and compare the maximum concentration (Cmax) and time
to maximum concentration (Tmax) of epinephrine
administered via tibial intraosseous (IO), sternal IO,
and intravenous (IV) routes in a porcine model of
cardiac arrest during cardiopulmonary resuscitation.
Five pigs each were randomly assigned to 3 groups:
tibial IO, sternal IO, and IV. Cardiac arrest was induced
with IV potassium chloride. After 2 minutes, cardiopulmonary resuscitation was initiated. Epinephrine
was administered to each animal, and serial blood
samples were collected over the next 3 minutes.
Enzyme-linked immunosorbent assay was used to
determine the epinephrine concentration. Multivariate
analysis of variance helped determine if there were
C
ardiac arrest remains one of the leading causes
of mortality, with more than 900 occurrences
daily in the United States.1,2 When a patient
experiences cardiac arrest, it is critical to
rapidly establish vascular access to administer
lifesaving drugs. Given that the patient is in a state of
cardiovascular compromise, vascular access procedures
become difficult and time-consuming. The difficulty and
delay in establishing vascular access may be magnified
during mass casualty scenarios or a situation such as when
multiple limbs are traumatically amputated in the same
patient. These factors can contribute to excessive delay in
obtaining vascular access, with resultant loss of life.
Although there are limited data, the American Heart
Association, American Academy of Pediatrics, and the
American College of Surgeons recommend that if intravenous (IV) access cannot be attained, drugs should
be administered by the intraosseous (IO) route. In both
statistically significant differences between groups.
There were significant differences in Cmax between
the sternal IO and IV (P = .009) and tibial IO and IV (P
= .03) groups but no significant difference between
tibial and sternal IO groups (P = .75). Significant differences existed in Tmax between the tibial IO and IV
(P = .04) and between tibial IO and sternal IO (P = .02)
groups but no difference between the sternal IO and
IV groups (P= .56). Intravenous administration of 1 mg
of epinephrine resulted in a serum concentration 5.87
and 2.86 times greater than for the tibial and sternal
routes, respectively.
Keywords: Advanced Cardiac Life Support, cardiac
arrest, epinephrine, intraosseous.
civilian and military medicine, IO infusion is an accepted
practice. The technique is taught in both adult and pediatric Advanced Trauma Life Support and Advanced
Life Support provider courses. Additionally, IO infusion
is used in special operations medicine by all military
branches. The IO method possesses the advantages of
ease and speed of placement, allowing rapid access to
the circulatory system. Furthermore, IO allows the safe
administration of fluids and drugs with the potential for
bioequivalence with IV-administered drugs.3 However, it
has not been determined if the anatomic location of the
IO device has an impact on drug bioavailability. Nor has
it been determined if there are differences between the IO
and IV concentrations of epinephrine when administered
during cardiac arrest.
The purpose of this study was to compare and determine the maximum concentration (Cmax) and time
to maximum concentration (Tmax) of epinephrine ad-
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ministered via tibial IO, sternal IO, and IV routes in a
porcine model of cardiac arrest during cardiopulmonary
resuscitation (CPR). The research questions that guided
the study were as follows:
1.Are there statistically significant differences in the
Cmax of epinephrine in the heart when the drug is administered via tibial IO, sternal IO, and IV routes in a
cardiac arrest scenario during CPR?
2.Are there statistically significant differences in the
Tmax of epinephrine in the heart when the drug is administered via tibial IO, sternal IO, and IV routes in a
cardiac arrest scenario during CPR?
Physiologic and pharmacodynamic effects of fluids
and medications administered through the IO route have
been studied and documented for decades. Studies have
compared the pharmacokinetics of medications administered via the IO route compared with the IV route.4-8
Tobias and Nichols5 reported the use of succinylcholine
using the tibial IO route in a pediatric patient and found
that with a dose of 1 mg/kg, adequate intubating conditions were obtained in 45 seconds.
The results from several animal studies suggest the
IO route is equivalent to the IV route for a wide variety
of medications. Jaimovich et al6 compared IO and IV
administration of an anticonvulsant in a porcine model.
In another study, Jaimovich and colleagues7 evaluated
IO vs IV administration of antibiotics. Brickman et al8
compared the 2 approaches in the administration of diazepam and phenobarbital in dogs. Similarly, Cameron and
associates9 compared the times between IO and IV injection using a radionucleotide technique in normovolemic
and hypovolemic canines. Goldstein et al10 examined the
pharmacokinetics of ampicillin administered by IV and IO
in kittens. Other authors investigated the effect of route of
administration on the pharmacokinetics of amikacin administered by IV and IO routes in 3- and 5-day-old foals.11
Chastagner et al12 examined antibiotic administration
via a permanent IO device in swine. In all of the aforementioned studies, there were no statistically significant
differences between the 2 routes of administration.
Dubick and colleagues13 evaluated hemodynamic
variables and electrolyte concentrations in euvolemic
swine infused with a bolus of 4 mL/kg of 6% hetastarch
via the sternal IO or IV route. Furthermore, they looked
for evidence of histologic abnormality in the sternum
and lung tissue. There were virtually identical responses
in hemodynamic variables, plasma volume expansion,
changes in plasma protein concentrations, hematocrit,
and plasma electrolytes when evaluated during the initial
120 minutes after infusion. No histologic changes or
emboli were found during necropsy. Similarly, rapid restoration of hemodynamic values was reported in hemorrhaged, conscious sheep after 6% hetastarch infusion via
a sternal IO device.14 Other investigators have reported
the effectiveness of IO infusion of hypertonic saline in
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resuscitating animals from hemorrhagic hypotension.15,16
Spivey et al17 investigated the administration of sodium
bicarbonate infusion via the IO route and stated that the
IO route is equivalent to peripheral IV.
To date, only one study in human subjects has compared the pharmacokinetics of drugs administered by the
2 routes. Von Hoff and colleagues18 found no statistically
significant differences between IO and IV administration
of morphine sulfate in adults. The authors emphasized
that the major limitation of this study was that they
evaluated only morphine sulfate and the findings may
not apply to other classes of drugs. Another limitation
they indicated was that the IO administration of morphine might not be generalized to IO administration of
medications in emergency situations or through other IO
devices designed for emergency use. They recommended
future studies of other drugs and other IO devices.
Specifically, those medications used in emergencies must
be investigated.
There are limited studies evaluating drug delivery
during cardiac arrest. Recent studies by Hoskins et al19
compared IO and IV routes of administration during CPR
after cardiac arrest. These studies showed that tibial IO
delivery was slower than but as effective as IV delivery
and that humeral head IO delivery was as effective as
either IV or sternal IO. In these studies, labeled epinephrine was found to be equivalent between the IO and IV
routes based on the appearance of tracers in central circulation. However, these studies did not quantify the Cmax
and Tmax of epinephrine in the circulation, as we did in
the current study.
Materials and Methods
This study was a prospective, experimental mixed
(between and within subjects) design. Computergenerated numbers were used to randomly assign 15
Yorkshire-cross swine weighing between 50 and 70 kg to
3 groups: tibial IO (n = 5), sternal IO (n = 5), or peripheral IV (n = 5). The swine were purchased from the same
vendor, were of equal size, were the same sex, and came
from the same lot number to minimize variability. Male
swine were used to avoid potential hormonal effects.
The swine were fed a standard diet and observed for
3 days to ensure a good state of health. The subjects had
nothing by mouth after midnight the day before the experiment. Buprenorphine (0.01 mg/kg) was administered
intramuscularly 30 minutes before anesthetic induction
for preemptive analgesia. Each animal was sedated, anesthetized, and mechanically ventilated 30 minutes before
instrumentation. Anesthesia was induced with an intramuscular injection (5 mg/kg) of tiletamine hydrochloride/
zolazepam hydrochloride (a mixed drug consisting of a
dissociative similar to ketamine and a benzodiazepine)
and inhaled 4% to 5% isoflurane. Following endotracheal
intubation, the isoflurane concentration was reduced
AANA Journal  August 2012  Vol. 80, No. 4  Special Research Edition S7
to a maintenance dose of 2% to 3% for the remainder
of the experiment. The animals were ventilated at a
tidal volume of 8 to 10 mL/kg and a respiratory rate of
10/min to 14/min (Fabius GS anesthesia machine, Dräger
Medical Systems, Telford, Pennsylvania). The swine were
monitored continuously during the entire experiment
for heart rate, arterial blood pressure, oxygen saturation, end-tidal carbon dioxide, and temperature (using
an Infinity Delta XL monitor, Dräger Medical Systems,
Telford, Pennsylvania). Peripheral IV access was placed
in the left ear of all subjects. Normal saline (NS, 0.9%)
was administered at 100 mL/h to maintain patency.
Normothermia was maintained in each animal by the
use of a forced-air warming blanket (Bair Hugger Model
505, Arizant Inc, Eden Prairie, Minnesota) to sustain
body temperature greater than 36.0°C. An 8.5F, 10-cm
central venous catheter (Cordis, Arrow International Inc,
Reading, Pennsylvania) was inserted in the right subclavian vein of all animals using the modified Seldinger
technique, for the purpose of blood specimen collection
from the right atrium.
Animals in the tibial IO group had a 2.5-cm IO
needle (EZ-IO AD, Vidacare Inc, San Antonio, Texas)
placed in the proximal medial aspect of the left tibia.
Animals in the sternal IO group had the same model of
2.5-cm needle placed in the upper sternum. Placement
confirmation in both IO groups consisted of aspiration
of bone marrow and rapid infusion of 10 mL of 0.9%
NS according to the manufacturer’s recommendation.
Sternal IO needle placement was guided by live fluoroscopy (GE OEC 9600, Salt Lake City, Utah) because of
the unique segmented anatomy of the porcine sternum.
Fluoroscopy prevented insertion of the IO needle in a
poorly perfused cartilaginous region of the sternum or
into the mediastinum. Fluoroscopy is unnecessary in
humans, as the sternum ossifies following embryologic
development. Following sternal IO device placement,
we injected iohexol contrast solution (GE Healthcare
Inc, Princeton, New Jersey), 300 mg/mL, through the IO
needle using an injector (Mark V ProVis, Medrad Inc,
Indianola, Pennsylvania) to confirm successful access to
the circulation. The animals were allowed to stabilize for
15 minutes following IO device placement.
After stabilization, we induced cardiac arrest with IV
potassium chloride, 20 mg/kg, and flushed with 10 mL
of 0.9% NS. The electrocardiographic waveform was observed, and asystole was confirmed in 2 leads before discontinuation of anesthesia. A stopwatch was used to time
an elapse of 2 minutes following confirmation of asystole.
After the 2-minute period, external chest compressions
were delivered by a continuous-compression mechanical CPR device (Thumper Model 1007CC, Michigan
Instruments Inc, Grand Rapids, Michigan). This device
compressed the sternum at a predetermined depth of
3.8 cm (1.5 in) and at a rate of 100/min according to
American Heart Association guidelines.20 It was used to
ensure the rate and depth of compressions delivered were
consistent over time and were reproducible from animal
to animal. Manual ventilations were delivered via the anesthesia circuit at a ratio of 2:30 compressions.
After 1 minute of CPR, a baseline blood specimen
was collected via the large-diameter central venous catheter, followed by a 10-mL 0.9% NS flush in all groups.
Epinephrine at a dose of 1 mg was rapidly administered
by IV, tibial IO, or sternal IO push, followed by 10 mL
of 0.9% NS. Blood specimens were collected via the
central venous catheter every 30 seconds following administration of epinephrine for 3 minutes, for a total of
7 specimens including the baseline, as timed by a stopwatch. Before each specimen collection, the researchers
aspirated and discarded 5 mL of blood and fluid from the
catheter to avoid dilution of the specimen. External chest
compressions were continued in each animal throughout
the 3-minute specimen collection. Adequacy of compressions was confirmed by palpation of femoral pulse
and the presence of an arterial blood pressure waveform
measured on the vital signs monitor. All blood samples
were collected in labeled heparinized tubes and were immediately centrifuged. The concentration of epinephrine
in plasma was determined by use of enzyme-linked immunosorbent assay (ELISA).
Results
The minimum number of animals was used to obtain a
statistically valid result. The determination of effect size
for this experiment was based on previous work.19 Using
the data reported in those studies, it was calculated that
the treatment group had a moderate effect size of 0.6.
Using statistical power analysis software (G*Power 3.00
for Windows), an effect size of 0.6, a power of 0.80,
2-sided testing, and an α of 0.05, we determined that a
sample size of 5 swine per group would be needed for
the study.
A multivariate analysis of variance (MANOVA) was
used to determine if there were significant differences in
the groups. A Wilks Λ indicated there were significant
differences between the groups (P = .01). A Tukey post
hoc analysis was used to determine where the significance was. Pigs of similar size and weight were used in
all 3 groups; there were no significant differences in the
weights of the pigs by group (P > .05). It was anticipated
that the stress of anesthesia, instrumentation, and CPR
would generate the release of endogenous epinephrine.
The amount of endogenous epinephrine secreted should
be relatively the same in all groups. To validate this assumption, we compared the baseline concentration of
epinephrine across the 3 groups. There were no significant differences in the baseline data (P > .05).
The Cmax was compared across the 3 groups (Figure
1). The Cmax for the tibial IO group ranged from 1,038
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160
20,000
140
120
100
Tmax (s)
Cmax (ng/mL)
15,000
10,000
80
60
40
5,000
20
0
Tibial IO
Sternal IO
IV
Figure 1. Mean Maximum Concentration of Epinephrine Administered via 3 Routes in a Porcine Model of
Cardiac Arrest During Cardiopulmonary Resuscitation
Abbreviations: Cmax, mean maximum concentration; IO, intraosseous; IV, intravenous.
to 5,260 ng/mL, with a mean (±SD) of 3,371 ± 1,561
ng/mL, the Cmax for the sternal IO group ranged from
3,314 to 18,617 ng/mL (mean, 6,924 ± 6,551), and the
Cmax for the IV group ranged from 8,579 to 38,768
ng/mL (mean, 19,810 ± 12,323). There were significant differences in Cmax between the sternal IO and
IV groups (P = .009) and tibial IO and IV groups (P =
.03) but no significant difference between the tibial and
sternal IO groups (P = .75). The IV administration of
1 mg of epinephrine resulted in a serum concentration
5.87 and 2.86 times greater than for the tibial and sternal
routes of administration, respectively.
The Tmax was also compared across the 3 groups
(Figure 2). The Tmax for the tibial IO group ranged from
150 to 180 seconds (mean, 156 ± 13 seconds); for the
sternal IO group, from 30 to 120 seconds (mean, 60 ± 42
seconds); and for the IV group, from 30 to 180 seconds
(mean, 78 ± 69 seconds). There were significant differences in Tmax between the tibial IO and IV (P = .04) and
between the tibial IO and sternal IO (P = .02) groups but
no difference between the sternal IO and IV groups (P =
.56).
Discussion
Previous studies have clearly demonstrated the efficacy
and equivalence of IO drug delivery in both normovolemic and hypovolemic states. However, this study
suggests that during cardiac arrest with ongoing CPR,
the Cmax of epinephrine is higher when administered
through a peripheral IV compared with both tibial and
sternal IO routes. This may be a result of impaired bone
marrow perfusion during cardiac arrest. There may also
be a relationship between the anatomical location of the
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0
Tibial IO
Sternal IO
IV
Figure 2. Mean Time to Maximum Concentration of
Epinephrine Administered via 3 Routes in a Porcine
Model of Cardiac Arrest During Cardiopulmonary
Resuscitation
Abbreviations: Tmax, mean time to maximum concentration; IO,
intraosseous; IV, intravenous.
IO device and serum drug concentrations; the more distal
the IO infusion site is from the sampling site, the longer
concentrations of drug take to rise. Another possible explanation is a local vasoconstrictive effect of epinephrine
in the bone marrow circulation impairing drug delivery
to the systemic circulation. Epinephrine delivery may
differ substantially from other drugs that have not yet
been studied in a cardiac arrest scenario.
The Advanced Cardiac Life Support (ACLS) recommendation for the endotracheal administration of epinephrine is 2 to 2.5 times the IV dose. The Pediatric
Advanced Life Support (PALS) recommendation for endotracheal epinephrine is 10 times the IV dose. Whereas
no studies were used to establish these dosage guidelines,
it has been demonstrated that equivalent doses of endotracheal epinephrine are less effective than IV epinephrine.21 However, the current guidelines for administration of epinephrine are the same for both the IO and IV
routes. The findings of this study suggest that higher
doses of epinephrine may be needed when administered
via the IO route to patients in cardiac arrest, compared
with the IV route.
The time to peak concentration was similar in the IV
and sternal IO groups, but it was significantly delayed in
the tibial IO group. Hoskins and colleagues19 also demonstrated a delay in delivery from the tibial IO compared
with other IO sites.
At this time, we do not recommend changing the guidelines of administering 1 mg of epinephrine by the IO route
because of the limitations of this pilot study. Specifically,
the sample size was small, there was wide variability within the groups, and specimen collection from the
AANA Journal  August 2012  Vol. 80, No. 4  Special Research Edition S9
venous side may not be ideal. Furthermore, although
the ELISA method of evaluating the Tmax and Cmax is
appropriate for this study, the use of high-performance
liquid chromatography with tandem mass spectrometry–mass spectrometry (HPLC-MS/MS) is considered to
be more accurate and precise. Indeed, HPLC-MS/MS is
considered to be the gold standard method of measuring
serum epinephrine levels. Future studies should include a
larger sample size; collection of blood specimens from the
arterial circulation, preferably at the aortic outlet; use of
larger volume saline flush following epinephrine administration; and the use of HPLC-MS/MS for analyses.
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AUTHORS
James Burgert, CRNA, MSNA, is a staff nurse anesthetist and clinical
instructor, Brooke Army Medical Center, Fort Sam Houston, Texas; an
adjunct assistant professor of nursing at Northeastern University, Boston,
Massachusetts; and a doctoral student at Texas Wesleyan University, Fort
Worth, Texas. Email: [email protected].
Brian Gegel, CRNA, MSN, was, at the time of the study, assistant
program director, Phase II Clinical Site for US Army Graduate Program in
Anesthesia Nursing, Fort Sam Houston. He is currently an independent
contractor of anesthesia services in private practice, an adjunct assistant
professor of nursing at Northeastern University, Boston, and a doctoral
student at Texas Wesleyan University.
LTC Michael Loughren, CRNA, PhD, ANC, USA, was, at the time of
the study, deputy director, US Army Graduate Program in Anesthesia
Nursing, Fort Sam Houston. He is currently chief nurse anesthetist at
Madigan Army Medical Center, Fort Lewis, Washington.
Thomas Ceremuga, CRNA, PhD, LTC(ret), ANC, USA, is assistant
director of research, US Army Graduate Program in Anesthesia Nursing,
Fort Sam Houston.
Manish Desai, MD, was, at the time of the study, a pediatric critical care
medicine fellow, University of Texas Health Science Center, San Antonio,
Texas. He is currently a pediatric intensivist at Scott and White Healthcare,
Temple, Texas, and an assistant professor of pediatrics at the Texas A&M
Health Science Center College of Medicine, College Station, Texas.
LTC Michael Schlicher, RN, PhD, ANC, USA, was, at the time of the
study, the assistant director of nursing research at Brooke Army Medical
Center, Fort Sam Houston. He is currently the director of nursing research
at Tripler Army Medical Center, Honolulu, Hawaii.
COL Joseph O’Sullivan, CRNA, PhD, ANC, USA, is director, US Army
Graduate Program in Anesthesia Nursing, Fort Sam Houston.
COL Paul Lewis, RN, PhD, ANC, USA, was, at the time of the study,
director of nursing research, Brooke Army Medical Center, Fort Sam
Houston. He is currently an assistant professor of nursing in the Graduate
School of Nursing at the Uniformed Services University of the Health Sciences, Bethesda, Maryland.
Don Johnson, RN, PhD, Col(ret), USAFR, NC, is director of research,
US Army Graduate Program in Anesthesia Nursing, Fort Sam Houston.
ACKNOWLEDGMENT
This study was funded by a grant from the American Association of Nurse
Anesthetists Foundation, Park Ridge, Illinois.
DISCLAIMER
The views expressed in this research paper are those of the authors and do
not necessarily reflect the official policy or position of the Department of
the Army, Department of Defense or the US Government. Title 17 U.S.C.
105 provides that “Copyright protection under this title is not available for
any work of the United States Government.” Title 17 U.S.C. 101 defines a
United States Government work as a work prepared by a military service
member or employee of the United States Government as part of that
person’s official duties.
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