Determination of Etomidate in Human 

Postmortem Fluids and Tissues

Robert D. Johnson

Russell J. Lewis

Civil Aerospace Medical Institute

Federal Aviation Administration

Oklahoma City, OK 73125

February 2009

Final Report

DOT/FAA/AM-09/3

Office of Aerospace Medicine

Washington, DC 20591
NOTICE

This document is disseminated under the sponsorship 

of the U.S. Department of Transportation in the interest 

of information exchange. The United States Government 

assumes no liability for the contents thereof.

___________

This publication and all Office of Aerospace Medicine 

technical reports are available in full-text from the Civil 

Aerospace Medical Institute’s publications Web site: 

www.faa.gov/library/reports/medical/oamtechreports/index.cfm


Technical Report Documentation Page 

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. 

DOT/FAA/AM-09/3 

4. Title and Subtitle 5. Report Date 

Determination of etomidate in human postmortem fluids and tissues February 2009 

6. Performing Organization Code 

 

7. Author(s) 8. Performing Organization Report No. 

Johnson RD, Lewis RJ 

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) 

FAA Civil Aerospace Medical Institute 

P.O. Box 25082 11. Contract or Grant No. 

Oklahoma City, OK 73125 

12. Sponsoring Agency name and Address 13. Type of Report and Period Covered 

Office of Aerospace Medicine 

Federal Aviation Administration 

800 Independence Ave., S.W. 

Washington, DC 20591 14. Sponsoring Agency Code 

15. Supplemental Notes 

Work was accomplished under approved task AM- B-05-TOX-204. 

16. Abstract 

Following an aviation accident, biological specimens from the operator of the aircraft are submitted to the 

Federal Aviation Administration’s Civil Aerospace Medical Institute for toxicological analysis. During the 

course of medical treatment following an aviation accident, pilots who later died as a result of their injuries 

may have been administered etomidate as an intravenous anesthetic. Our laboratory has developed a sensitive 

method for the identification and quantitation of etomidate in the biological specimens received from these 

pilots. Furthermore, we have evaluated the distribution of this compound in various postmortem tissues and 

fluids from 3 fatal aviation accident cases. When available, 10 specimen types were analyzed for each case, 

including blood, urine, vitreous humor, liver, kidney, skeletal muscle, lung, spleen, heart muscle, and brain. 

Specimens were extracted using solid-phase base extraction and analyzed by GC/MS. Deuterated etomidate 

was not available as an internal standard, so to eliminate any possible matrix effects during extraction all 

quantitative values in specimens other than blood were determined through standard addition. Blood 

etomidate concentrations in these three cases ranged from 12 to 41 ng/mL. Distribution coefficients for 

etomidate were determined for each of the specimen types analyzed. These coefficients are expressed relative 

to the blood concentration in that case. To our knowledge, this is the first report presenting the distribution 

of etomidate in humans at therapeutic concentrations. 

 

17. Key Words 18. Distribution Statement 

 

 

Forensic Toxicology, Etomidate, Distribution, 

Postmortem, Aircraft Accident Investigation 

Document is available to the public through the 

Defense Technical Information Center, Ft. 

Belvior, VA 22060; and the National Technical 

Information Service, Springfield, VA 22161 

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price 

Unclassified Unclassified 11 

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized 

iii

Contents

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Materials and Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Chemicals and Reagents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Gas Chromatographic/Mass Spectroscopic Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Sample Selection and Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Calibrator and Control Preparation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Sample Preparation and Extraction Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Extraction Efficiency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Results and Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Method Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Postmortem Concentrations of Etomidate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Determination of Etomidate in

Human Postmortem Fluids and Tissues

Introduction

Etomidate, [R-(+)-ethyl-1(phenylethyl)-1-H imidazole-5-carboxylate], is an intravenous anesthetic agent

first approved for use in the United States in 1983 and

marketed under the trade name Amidate®.

1 Prior to the

introductionofetomidate,themedical community lacked

an ideal agent for the induction of unconsciousness before certain medical procedures. This compound causes

rapid hypnosis in patients and may be used repeatedly

without tolerance.

1,2

Etomidate is rapidly absorbed following intravenous

administration. Peak plasma concentrations typically

occur within 4 minutes of introduction, and the half-life

has been reported to range from 2 to 11 hours.

3 Etomidate is extensively metabolized by hydrolysis in both

the plasma and in the liver to an inactive carboxylic acid

metabolite.

1,3,4 The chemical structure of etomidate can

be seen in Figure 1. The internal standard, SERTIS, was

used for all etomidate analysis. SERTIS, n-methyl-4-(4-

bromophenyl)-1,2,3,4,-tetrahydro-1-napthylamine, is a

generic internal standard used by our laboratory when

no deuterated analog is available. SERTIS is not sold for

humanconsumption,so there isno risk ofthis compound

being present in human specimens. 

Frequently,pilots involved inaviationaccidentssurvive

and are treated surgically in an effort to save their lives. 

However, these pilots do not always survive surgery. If

death occurs following medical treatment, postmortem

specimens are shipped to our laboratory for analysis. 

Thesespecimens aresubsequently found positivefor the

compounds used bymedical personnel during life-saving

procedures. Etomidate is onesuch compound. There are

relatively few published reports describing the analysis of

etomidate, and only 1 of these publications describes the

analysis by GC/MS.

5-9 Furthermore, scientific information concerning the distribution of etomidate in human

specimens is not available. This manuscript presents the

quantitation and distribution of etomidate in postmortem human specimens, including urine, vitreous humor,

skeletal muscle, liver, kidney, lung, spleen, brain, and

heart muscle. 

Materials and Methods

Chemicals and Reagents

All aqueous solutions were prepared using double

deionized water (DDW), which was obtained using a

Milli-QTplus Ultra-Pure Reagent Water System (Millipore®, Continental Water Systems, El Paso, TX). All

chemicals described below were purchased in the highest

possiblepurity andusedwithout any furtherpurification. 

Etomidate was purchased from Bedford Labs (Bedford

Laboratories, Bedford, OH) and received as a 2 mg/mL

standard in 35% v:v propylene glycol. The internal standard, SERTIS,was obtainedfromPfizer(PfizerInc.,New

York,NY). Methanol, acetonitrile, ammoniumhydroxide,

acetic acid,ethyl acetate,sodiumfluoride, and potassium

phosphatemonobasicwere purchased fromFisher Scientific (Fisher ScientificCo., Pittsburgh, PA). The pH of all

N

N

O

O

 Br

H

N

 Etomidate SERTIS

Figure 1. Chemical structures of etomidate and SERTIS. 
solutions was measured using a Corning model 430 pH

meter (Corning Life Sciences, Acton, MA) connected to

a Corning 3-in-1 model pH electrode.

Gas Chromatographic/Mass Spectroscopic Conditions

All analyses were performed using a bench-top gas

chromatograph/mass spectrometer (GC/MS), which

consisted of a Hewlett Packard (HP) 6890 series GC,

interfaced with a HP 5973 quadrupole MS (Agilent

Technologies Inc., Santa Clara, CA). The MS was tuned

onadailybasisusingperfluorotributylamine. Theelectron

multiplier voltagewas set at 106 eVabovethetune value. 

Chromatographic separationwas achieved using aVarian

FactorFour crosslinked 100% methyl siloxane capillary

column 12mx 0.2mm i.d., 0.33 μmfilmthickness(Var-

ianCo., HarborCity,CA.). Helium wasemployed as the

carrier gas and used at a flow rate of 1.0 mL/min. The

GC/MS transferline and sourcetemperatureswereset to

280°C and 250°C, respectively. An HP 6890 autosampler was used to inject 1 μL of extract into the GC/MS. 

The GC was equipped with a split/splitless injection

port operated at 250°C in the splitless mode with the

purgetime of 0.5 min. The oven temperature profile was

established as follows: 70°C – 290°C at 30°C/min and a

final hold time of 2.67 min, resulting in a total run time

of 10 min. Initially, neat standards ofeach compound (1

μL of a 100 ng/μL solution) were injected individually

and analyzed using the full scan mode of the GC/MS,

which scanned from 50 to 600 AMU. Thefull scan mass

spectra from these 2 compounds can be seen in Figures

2 and 3. Quantitation and qualifier ions foreach analyte

werethenselectedbasedonbothabundance andmass-tochargeratio (m/z). To increasereproducibility and reduce

interference, high-mass ionswereselectedwhen possible. 

The ions chosen for each respective analyte can be seen

in Table 1. Upon selection of unique ions, the MS was

run in selected ion monitoring (SIM) mode with a dwell

time of 30 msec for each recorded ion.

Sample Selection and Storage

Asearch oftheCAMI database identified 3 etomidatepositive fatalities from separate civil aviation accidents

fromtheprevious3yearsthathadamajorityofthedesired

biologicaltissues andfluids(blood,urine, vitreoushumor,

liver, kidney,muscle, lung,spleen, heart, and brain) availablefor analysis. In all cases, bloodwasstored at-20°C in

tubes containing1.00%(w/v)sodiumfluoride/potassium

oxalate until analysis. All other specimens were stored at

-20°C, with no added preservative, until analysis. 

Calibrator and Control Preparation

A calibration curve for etomidate was prepared by serial dilution, utilizing bovine whole blood as the diluent. 

Controls were also prepared using bovine whole blood as

the diluent. Calibrators were prepared from 1 stock standardsolution,while controlswerepreparedfroma second

separatestock solutionwith a differentmanufacturer’slot

number. A calibration curve was prepared at concentrations ranging from 0.39 – 800 ng/mL. A minimum of 7

calibrators were used to construct the calibration curve. 

Controls were prepared at concentrations of 80 and 320

ng/mL and extracted, with each batch of unknowns to

verify the accuracy of the calibration curve. The internal

standard solution was prepared at a concentration of 400

ng/mL in DDW by dilution from the stock standard of

this compound.

Quantitation of blood specimens was achieved via an

internal standard calibration procedure. Response ratios

for etomidate were determined for every blood sample

analyzed. The response ratio was calculated by dividing

the area of the analyte peak by the area of the internal

standardpeak. Calibrationcurveswerederivedbyplotting

a linearregressionofthe analyte/internalstandardresponse

ratio versus the analyte concentration foreach respective

calibrator. Standard addition was used to determine the

concentration ofetomidate in every specimen type other

than blood. This was necessary due to the possible matrix effects associated with the extraction of an internal

standard that is not a deuterated analog ofthe compound

of interest. Thestandard addition procedure used in this

work has been described extensively elsewhere.

10 Briefly,

a specimen was divided in half, 1 half was spiked with

a precisely known amount of etomidate, the other half

was not altered. Internalstandardwas added to each tube

and the 2 halves were analyzed. After analysis, the ratio

of the etomidate concentration in the unspiked sample

compared to the spiked sample allowed us to derive the

concentration in the original specimen.

Sample Preparation and Extraction Procedure

Postmortemspecimens, calibrators, and controlswere

extracted in thefollowingmanner. Tissuespecimenswere

homogenizedusinganOmni post-mountedhomogenizer

(Omni Int., Marietta, GA). The generator used with this

homogenizer had a diameter of 30 mm and rotated at

22,000 rpm. Tissues were homogenized following a 1:2

dilution with 1.00% NaF in DDW. Three mL aliquots

of postmortem fluids, calibrators, controls, and 3.00 g

aliquots of each tissue homogenate (1.0 g tissue) and

each standard addition sample were transferred to individual 16 x 150 mm screw-top tubes. To each specimen,

calibrator, and control, 1.00 mL of the internal standard

(400 ng) was added. Samples were vortexed briefly and

allowed to stand at room temperature for 10 min. Nine

mL ice-cold acetonitrile was added to each sample. The

mixture was then placed on a rotary mixing wheel and
Table 1. Ions utilized for the quantitation of fluoxetine etomidate. 

Compound Ions utilized for quantitation (m/z)

*

Etomidate 105, 244, 199 

SERTIS 286, 284, 314 

* Ions in bold used for quantitation, other ions used as qualifiers. 

40 60 80 100 120 140 160 180 200 220 240 260

0

 500000 

1000000 

1500000 

2000000 

2500000 

3000000 

3500000 

m/z--> 

Abundance 

105

244 

77

95

199

40 51 67 115 128 143 155 172 183 215 229 258

Figure 2. Full scan mass spectra of etomidate. 

40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 0

100000 

300000 

500000 

700000 

900000 

1100000 

1300000 

1500000 

1700000 

m/z--> 

Abundance 

286 

205 

159 272 178 

104 129 

89 116 144 191 258 314 

42 63 77

235

Figure 3. Full scan mass spectra of SERTIS. 
mixed at 15 rpm for 15 min. Centrifugation at 820×g

for 5 min removed cellular debris and proteins. Follow-

ing centrifugation, the supernatant was transferred to

clean 16 x 125 mm culture tubes and evaporated in a

TurboVap ConcentrationWorkstationat40°C(Caliper

Life Sciences, Hopkinton, MA) under a stream of dry

nitrogen to a volume of approximately 1 mL. Following

acetonitrileevaporation,4.00mL0.10Mphosphate buffer, pH 6.00,was added to each sample. Theextractswere

transferred to Bond EluteCertify® solid-phaseextraction

(SPE) columnsobtainedfromVarian(VarianCo.,Harbor

City, CA.), which had been pre-conditioned with 2.00

mL methanol, followed by 2.00 mL 0.10 M phosphate

buffer, pH 6.00. Care was taken not to dry the column

prior to adding the extract. Column flow rates of 1-2

mL/min were maintained in each SPE step using a Var-

ian 24 port Cerex SPE processor (Varian Co., Harbor

City, CA.) with a nitrogen pressure of 3 psi. Once each

sample had passed through its respective column, the

columns were washed with 1.00 mL of 1.00 M acetic

acid and then dried completely with 25 psi nitrogen for

5 min. The columns were again washed with 6.00 mL. 

Following the methanol wash, the columns were again

dried completely with 25 psi nitrogen for 5 min. The

analytes were eluted off the columns with 3.00 mL of

2% ammonium hydroxide in ethyl acetate, which was

preparedfreshdaily. Eluentswereevaporatedtodryness in

aTurboVap set at 40°C under a stream of dry nitrogen. 

Once dry, the contents of each tube were reconstituted

in 50 μL ofethyl acetate and transferred to GC/MS vials

for analysis.

Extraction Efficiency

The method used for the determination of analyte

recoveryhaspreviouslybeenreported.

11Brieflydescribed,

2 groups of controls, X and Y, prepared using negative

whole blood, were extracted in the same manner as describedabove. GroupXwasspikedwithapreciselyknown

concentrationofetomidatepriorto SPEextraction,while

group Y was spiked with the same precisely known concentration ofetomidatefollowing SPE extraction. Upon

analysis,the averageresponsefactor obtained fromgroup

X was divided by the average response factor obtained

from group Y to yield the percent recovery value (100 *

(X/Y) = % recovery) for etomidate.

Results and Discussion

Method Validation

The procedure described herein, which utilizes SPE

and GC/MS for the detection of etomidate, is rapid, reproducible, and sensitive. Analyte peakswere completely

resolved, andeachprovidedquantitation ionswithunique

m/z, so no interference was observed. Retention times

for etomidate and SERTIS were typically 4.75 and 6.10

min, respectively. No analyte suffered interference from

endogenous/exogenous matrix components. Standard

addition was used for specimen types other than blood

whileusing abloodcalibrationcurve,thereby eliminating

any matrix effect concerns.

The full-scan mass spectra of etomidate and SERTIS

provided numerous high mass ions; these spectra can be

seen in Figures 2-3. Quantitation and qualifier ions for

eachcompoundareshown inTable1. Acceptabilitycriteria

employedfor analyte identificationandquantitationwere

as follows: 1) ion ratios for a given analyte, measured as

the peak area of a qualifier ion divided by the peak area

of the quantitation ion, were required to be within ±

20% of the average of the ion ratios for calibrators used

to construct the calibration curve; 2)each ion monitored

was required to have a minimum signal-to-noise ratio

(S/N) of 10; and 3) the analyte was required to have a

retention time within ± 2.00% of the average retention

time for calibrators used to construct the calibration

curve. Analytes not meeting these criteria were reported

as either negative or inconclusive.

The linear dynamic range (LDR), limit of detection

(LOD), and limit of quantitation (LOQ) for etomidate

were determined using whole blood as the matrix. The

LDR was determined to be 0.78 – 400 ng/mL. The

correlation coefficient for the calibration curve used to

evaluate the LDR was 0.998 when employing a weight-

ing factor of 1/X. The injection of an ethyl acetate blank

following the 400 ng/mL calibrator showed no carryover

contamination. Subsequently, ethyl acetate blanks were

utilized between each postmortem specimen throughout

the sample sequence to verify that no sample-to-sample

contamination had occurred. The LOD was defined as

the lowest etomidate concentration detectable that met

the above-discussed identification criteria. The LOQwas

defined as thelowestetomidate concentration detectable

thatnotonlymet all identificationcriteriadiscussedabove

but also had an experimentally determined concentration within ± 20% of its prepared value. The LOD for

etomidate was determined to be 0.39 ng/mL, while the

LOQ was determined to be 0.78 ng/mL.

Theextractionefficiency foretomidatewasdetermined

at two different concentrations. The recovery of etomidate at 50 ng/mL was determined to be 79%, while the

recovery at 400 ng/mL was 91%. Recovery values above

75% are exceptional when considering the simplicity of

the extraction and the use of whole blood as the matrix

for these experiments.

Intra-day and inter-day accuracy and precision were

examined for this extraction procedure. Accuracy was

measured astherelativeerror between theexperimentally
determinedandpreparedconcentrationsof awhole-blood

control. Precision was measured as the relative standard

deviation (RSD) of the experimentally determined concentrations of a group of whole blood controls. Pools of

controls were created at 80 ng/mL and 320 ng/mL in

volumes large enough to be used for the entire accuracy

and precision investigation. These controls were stored

at 4°C for the duration of this study. For the intra-day

accuracy and precision experiment, a calibration curve

was extracted, along with 5 replicates of each control

concentration. As shown in Table 2, etomidate at both

concentrations yielded relative errors within 5% of the

target concentration. Furthermore, the RSD associated

with this experiment was found to be 2% at each concentration. These results demonstrate the exceptional

accuracy and precision of this method.

Inter-day accuracy and precisionwereevaluated by extracting5replicatesofeachofthe2control concentrations

on Days 2, 4, and 7. The quantitative values determined

on each of these days were derived from the calibration

curves originally prepared onDay 1. Theresults obtained

after storage of each control lot at 4°C for 2, 4, and 7

days can be seen in Table 2. Etomidate concentrations

determined over this 7-day period showed no significant

difference from those obtained on Day 1. The RSDs

for etomidate were less than 5% on Days 2, 4, and 7. 

Even though no apparent decrease in concentration was

observed over the 7-day storage period at 4°C, as a good

laboratory practice,werecommend prompttoxicological

analysis once a postmortem specimen has been thawed

and preparing a new calibration curve at the beginning

of each new analysis.

Postmortem Concentrations of Etomidate

Blood concentrations found in these 3 cases ranged

from 12 to 41 ng/mL. Therapeutic levels of etomidate

in plasma rangefrom 220 to 410 ng/mL.

3The published

plasma/whole blood ratio is 0.62. Therefore,therapeutic

blood concentrationsforetomidate inwhole blood range

from 354 to 661 ng/mL. Blood concentrations in these

cases were all found to be below therapeutic levels. The

concentration of etomidate in each postmortem specimen from these 3 cases can be seen in Table 3. With a

volume of distribution of 2-7 L/kg,1 etomidate was expected to be found at higher concentrations in the tissue

specimens analyzed. As can be seen in Table 3, this was

the case. It appears that etomidate is rapidly distributed

following administration. It has also been found that

this compound is extremely lipid soluble.

12 Therefore,

brain concentrations are expected to be relatively high. 

The following mean concentrations of etomidate were

found: blood 25 ng/mL, urine 9 ng/mL, vitreous humor

3 ng/mL, liver 128 ng/g, lung 40 ng/g, kidney 150 ng/g,

spleen 119 ng/g, muscle 61 ng/g, brain 128 ng/g, and

heart 119 ng/g. The individual concentrationsfrom each

case can be seen in Table 3. The distribution coefficients

for etomidate, expressed as specimen/blood ratios, are

summarized in Table 4. The distribution coefficients

for etomidate were determined to be: urine 0.4 ± 0.1,

vitreous humor 0.17 ± 0.08, liver 4 ± 1, lung 1.6 ± 0.5,

kidney 5 ± 1, spleen 4 ± 1, muscle 3 ± 1, brain 5 ± 1,

and heart 6 ± 2. As can be seen in Table 3, etomidate

distribution coefficients for urine, bile, vitreous humor,

muscle, kidney, lung, spleen, brain, liver, and heart had

coefficient of variation (CV) values between 20 and 47%. 

It is widely accepted that basic drugs with large volumes

of distribution can undergo postmortem redistribution. 

This redistribution may account for some of the larger

CV values observed.

Table 2. Intra-day accuracy and precision for 

repeated determinations over 7 days.*

Etomidate 

Day 1 

Target Conc. 80 320 

Mean SD 79 2 333 8 

Relative Error -1% +4% 

R.S.D. 2% 2% 

Day 2 

Target Conc. 80 320 

Mean SD 73 2 315 7 

Relative Error -9% -2% 

R.S.D. 3% 2% 

Day 4 

Target Conc. 80 320 

Mean SD 80 1 334 4 

Relative Error 0% +4% 

R.S.D. 1% 1% 

Day 7 

Target Conc. 80 320 

Mean SD 82 2 335 7 

Relative Error +3% +5% 

R.S.D. 2% 2% 

 *n=5 at each concentration for each day; controls 

were run on days 1, 2, 4, and 7.
There are no widely accepted criteria for what constitutes a reliable distribution coefficient; however, with

certain drugs it may be possible, with caution, to use a

tissue or fluid distribution coefficient to crudely estimate

a blood concentration in cases where blood is not available, if the distribution coefficient has a CV of < 25%. 

Our laboratory receives blood in only approximately

70% of the cases that we analyze. Therefore, the results

obtained from the limited number of cases (n=3) in this

study suggestthatetomidate concentrationsfound inliver,

kidney, brain, and spleen could be used with caution to

estimate blood etomidate concentrationsthat areslightly

below therapeutic levels. We acknowledge that a study

involving a greater number of samples from a larger pool

of cases needs to be completed to more definitively verify

theseresults. However, based on these findings one could

cautiously estimate a range for postmortem etomidate

concentrations in blood.

Table 3. Etomidate concentrations obtained from 3 pilot fatalities.*

Case Blood Urine VH Liver Lung Kidney Spleen Muscle Brain Heart 

1 12 6 3 29 12 48 32 33 49 83 

2 21 — 2 92 46 152 79 87 132 167 

3 41 11 — 262 63 251 246 63 202 108 

* All concentrations shown in units of ng/mL or ng/g

—Specimen type not available for analysis 

Table 4. Postmortem etomidate-positive specimen distribution coefficients. 

Urine/

Blood

VH/

Blood

Liver/ 

Blood

Lung/

Blood

Kidney/ 

Blood

Spleen/ 

Blood

Muscle/ 

Blood

Brain/

Blood

Heart/

Blood

n 2 2 3 3 3 3 3 3 3 

Mean 0.4 0.17 4 1.6 5 4 3 5 6 

s.d. 0.1 0.08 1 0.5 1 1 1 1 2 

CV 25 47 25 31 20 25 33 20 33 

Conclusion

In thisstudy, ourlaboratory developed and validated a

novelmethod fortheextraction and analysis ofetomidate

inhumanbiologicalspecimens. Theresultsobtainedfrom

these cases suggest that etomidate is readily absorbed by

all tissues and fluids in the body. Although etomidate

distribution varied among individuals, there wereseveral

specimentypesthatshowedrelatively consistentdistributioncoefficients. Liver, kidney,brain, andspleeneachhad

a CV of less than 25% (n=3). The relatively small CV

associated with these distribution coefficients suggests

thatthesespecimensmay be usedwith extreme cautionto

obtainanapproximatebloodconcentrationforetomidate

when blood is not available for analysis.
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