Postmortem detection of isopropanol in ketoacidosis

Isopropanol (IPA) detected in deaths because of diabetic ketoacidosis (DKA) or alcoholic ketoacidosis (AKA) may cause concern for IPA poisoning. This study addressed this concern in a 15-year retrospective review of 260 deaths in which concentrations of acetone and IPA, as well as their ratios, were compared in DKA (175 cases), AKA (79 cases), and IPA intoxication (six cases). The results demonstrated the frequency of detecting IPA in ketoacidosis when there was no evidence of IPA ingestion. IPA was detectable in 77% of DKA cases with quantifiable concentrations averaging 15.1 ± 13.0 mg/dL; 52% of AKA cases with quantifiable concentrations averaging 18.5 ± 22.1 mg/dL; and in cases of IPA intoxication, averaging 326 ± 260 mg/dL. There was weak correlation of IPA production with postmortem interval in DKA only (r = -0.48). Although IPA concentrations were much higher with ingestion, potentially toxic concentrations were achievable in DKA without known ingestion.     

Subnuclear renal tubular vacuoles in alcohol use disorder

Subnuclear vacuoles in the proximal renal tubules have been reported as a histologic sign of ketoacidosis. Originally described in diabetic ketoacidosis, renal vacuoles can be found in other ketogenic states such as alcoholic ketoacidosis (AKA), starvation, and hypothermia, underpinned by deranged fatty acid metabolism. A retrospective analysis of 133 deaths associated with alcohol use disorder (AUD) examined at autopsy between 2017 and 2020 was undertaken. This study aimed to determine the prevalence of subnuclear vacuoles in deaths of those with AUD and their specificity for deaths from AKA, and to elucidate what demographic, biochemical, and pathologic findings are associated with subnuclear vacuoles. In each case, vitreous humor biochemistry including electrolytes, glucose, and beta-hydroxybutyrate (BHB) was analyzed alongside postmortem hemoglobin A1c and renal and liver histology. Renal histology was graded for the presence of vacuoles as absent (0), scanty (1), or easily identifiable (2). Liver histology was graded for steatosis and for fibrosis if Masson trichrome staining was available. Vacuoles were commonly seen in the deaths of those with AUD. They were seen in deaths due to AKA but were not specific to that cause of death. With vacuoles present, lower vitreous sodium (139 vs. 142 mmol/L; p = 0.005), higher vitreous BHB (1.50 vs. 1.39 mmol/L; p = 0.04), severe hepatic steatosis, and severe hepatic fibrosis were seen, compared with those without renal vacuoles.     

Utility of Postmortem Vitreous Beta-Hydroxybutyrate Testing for Distinguishing Sudden from Prolonged Deaths and for Diagnosing Ketoacidosis

A retrospective, cross-sectional analysis of vitreous beta-hydroxybutyrate (BHB) on 967 forensic cases over a two-year period was conducted. Cases were sorted into six categories of death: (i) sudden traumatic/non-natural (ST), (ii) sudden natural (SN), (iii) prolonged traumatic/non-natural (PT), (iv) prolonged natural (PN), (v) diabetic ketoacidosis (DKA), and (vi) alcoholic ketoacidosis (AKA). The mean BHB for all cases was 1.67 mmol/L (17.4 mg/dL; range: 0.11–18.02 mmol/L). The numbers of DKA, AKA, PN, PT, SN, and ST deaths were 21, 5, 155, 258, 275, and 253, respectively. Their mean vitreous BHBs were as follows: 11.04 mmol/L (DKA), 8.88 mmol/L (AKA), 1.56 mmol/L (PN), 1.55 mmol/L (PT), 1.26 mmol/L (SN), and 1.38 mmol/L (ST). There was a statistically significant difference between the mean BHBs of the PN and SN death groups (p < 0.001), as well as between those of the PT and ST death groups (p = 0.004). Given the overlapping ranges seen between the prolonged and sudden death groups, the identified differences did not hold clinical significance. In addition, we sought to determine a threshold value for vitreous BHB to definitely diagnose cases of ketoacidosis. BHB threshold concentrations between 2.5 and 5 mmol/L produced sensitivities >92% and specificities >96%. A receiver operator characteristic curve found 3.43 mmol/L to be the optimal cutoff value, demonstrating a specificity of 98.3% and a sensitivity of 96.2%.     

Postmortem oxycodone and hydrocodone blood concentrations

There is limited data on postmortem oxycodone concentrations, consisting of three published reports with a total of 11 cases, many of which were polypharmacy cases. This report presents the results of a review of autopsy and coroner's reports from 10 counties for the years 2000 and 2001 to locate cases with oxycodone or hydrocodone exposure as a leading cause of death. Eighty-eight cases were located. Twenty-four deaths were attributed to oxycodone alone. Mean and median postmortem oxycodone blood concentrations were 1.23 mg/L and 0.43 mg/L, respectively. The range was 0.12 to 8.0 mg/L, with 13 cases (54%) < or = 0.5 mg/L. Seventeen deaths were attributed to hydrocodone alone. Mean and median postmortem hydrocodone blood concentrations were 0.53 mg/L and 0.40 mg/L, respectively. The range was 0.12 to 1.6 mg/L, with 11 cases (65%) < or = 0.5 mg/L. There were seven cases where the cause of death was attributed to the effects of a combination of hydrocodone and oxycodone. Mean oxycodone and hydrocodone blood concentrations were 0.34 mg/L and 0.14 mg/L, respectively. Forty cases involved polysubstance overdoses with significant involvement of other drugs and ethanol. Mean oxycodone and hydrocodone blood concentrations were 0.18 mg/L and 0.29 mg/L, respectively. The list of other substances involved was extensive but included ethanol, amitriptyline, methadone, codeine, propoxyphene, and acetaminophen. The findings of this study report oxycodone values associated with a fatality at blood concentrations lower than previously reported. This may represent enhanced information because of the larger sample group. Hydrocodone values associated with a fatality were similar to previously published values.     

The relationship of methanol and formate concentrations in fatalities where methanol is detected

An automated headspace gas chromatography method was developed for the determination of formate (formic acid) in postmortem specimens, based on the in situ sulfuric acid-methanol methylation of formic acid to methyl formate. Diisopropyl ether was used as an internal standard. The method was applied to over 150 postmortem cases where methanol was detected. Of the 153 cases presented, 107 deaths were attributed to acute methanol toxicity. In the vast majority of the remaining 46 deaths, the methanol was determined to be present as a postmortem or perimortem artifact, or was otherwise incidental to the cause of death. Of the 76 victims who were found dead and blood was collected by the medical examiner, all but one had a postmortem blood formate concentration greater than 0.50 g/L (mean 0.85 g/L; n = 74). The sole exception involved suicidal ingestion of methanol where the blood methanol concentration was 7.9 g/L (790 mg/100 mL) and blood formate 0.12 g/L. In 97% (72/74) of the cases where blood was available, the blood formate was between 0.60 and 1.40 g/L. In 31 of the 153 cases, the victim was hospitalized and blood obtained on admission or soon after was analyzed for methanol and formate during the subsequent death investigation; the vast majority (27/30) had antemortem blood formate concentrations greater than 0.50 g/L. Cases with samples taken prior to death with blood formate concentrations less than 0.5 g/L can readily be explained by active treatment such as dialysis. The blood formate method has also been useful in confirming probable perimortem or postmortem contamination of one of more fluids or tissues with methanol (e.g., windshield washer fluid or embalming fluid), where methanol ingestion was unlikely.     

Investigation of markers to indicate and distinguish death due to alcoholic ketoacidosis, diabetic ketoacidosis and hyperosmolar hyperglycemic state using post-mortem samples

Data from 191 post-mortem cases where post-mortem blood beta-hydroxybutyrate (βHB) and acetone concentrations and vitreous humor glucose concentrations (where available) had been measured were retrospectively investigated to determine the markers required to identify and distinguish between Alcoholic Ketoacidosis (AKA), Diabetic Ketoacidosis (DKA) and Hyperosmolar Hyperglycemic State (HHS). Blood βHB concentrations above 250 μg/mL were considered significant and it was shown to be the preferred marker of ketoacidosis. All cases with significant βHB detected also had acetone present (greater than 2mg/dL) demonstrating that acetone can be used as a marker to identify ketoacidosis and can be used to indicate when βHB measurement is necessary. Vitreous humor glucose concentrations above 6.9 mmol/L were considered high and indicative of hyperglycemia prior to death. Vitreous humor glucose concentrations can be used to distinguish between DKA and ketoacidosis from other causes and to identify deaths due to HHS. The data showed that ketoacidosis can occur without a history of alcoholism or diabetes. Many diabetics are undiagnosed for many years. Therefore, DKA or HHS should be considered in sudden or unexplained deaths and glucose should be routinely measured especially in cases with risk factors for diabetes including obesity, old age, a history of mental health problems or treatment with atypical antipsychotic drugs including clozapine, olanzapine, quetiapine and risperidone.     

Morbus Fahr--considerations on a case of sudden death

This paper presents 21 cases related to cyanide intoxication by oral ingestion. Cyanide concentrations in biological specimens are especially different from the type of postmortem specimens, and very important in interpreting the cause of death in postmortem forensic toxicology. Besides the detection of cyanide in autopsy specimens, the autopsy findings were unremarkable. Biological samples (0.2mL or equal to less than 10μg of cyanide) were analyzed colorimetrically for cyanide. In a series of 21 cyanide fatalities, the concentration ranges (mean±SD) of cyanide in heart blood, peripheral blood and gastric contents were 0.1-248.6mg/L (38.1±56.6mg/L), 0.3-212.4mg/L (17.1±45.1mg/L) and 2.0-6398.0mg/kg (859.0±1486.2mg/kg), respectively. The ranges of the heart/peripheral blood concentration ratio and gastric contents/peripheral blood concentration ratio were 0.3-10.6 (mean 3.4) and 3.4-402.4 (mean 86.0), respectively. From the difference of cyanide concentration and the concentration ratio of cyanide in different types of postmortem specimens, the possibility of the postmortem redistribution of cyanide and death by oral ingestion of cyanide could be confirmed. We reported cyanide fatal cases along with a review of literature.     

The routine use of C-reactive protein in forensic investigations

In clinical medicine, C-reactive protein (CRP) is extensively used as a general marker for immune system activation, and post-mortem applicability has been established [M.Q. Fujita, B.L. Zhu, K. Ishida, L. Quan, S. Oritani, H. Maeda, Serum C-reactive protein levels in postmortem blood-an analysis with special reference to the cause of death and survival time, Forensic Sci. Int. 130 (2002) 160-166; L. Uhlin-Hansen, C-reactive protein (CRP), a comparison of pre- and post-mortem blood levels, Forensic Sci. Int. 124 (2001) 32-35]. We have analysed the routine use of CRP in non-selected cases. Scarcity of blood available for analysis is a common problem in forensic investigation, and in response to this we have developed a method using liver as a source. In 50 consecutive autopsy cases, we have evaluated method, validated results and discussed their interpretation. In three cases the analysis was not possible. For each of the remaining cases (n=47) we have analysed whole blood, serum and/or liver samples. 57% (n=25) had serum CRP > 10 mg/L. Serum levels were higher than in whole blood or liver. CRP levels in serum and whole blood samples were stable in more than one month after death, making storage for later analysis possible. Liver levels peaked at one week, but after one month putrefaction was obvious. CRP levels were independent of the post-mortem interval. The use of liver as a source has not yet been described in literature. Our results in liver samples correlate well with plasma results, and liver is a good post-mortem alternative when blood is not available. We conclude that CRP measurements are easy, viable and inexpensive in a forensic setting, and that the number of cases with CRP elevation is high in a non-selected forensic material. In cases of doubt, marked elevation of CRP is an indicator of natural mode of death, and in cases of trauma, it indicates vital reaction. It can be used as a pre-autopsy screening, leading to a more extensive search for diseases not easily diagnosed, such as sepsis or ketoacidosis.     

Biochemical measurements of glucose metabolism in relation to cause of death and postmortem effects

This study was performed to examine the relationship between postmortem biochemical values and cause of death. The follow samples were taken from 399 corpses: cerebrospinal fluid (CSF; n = 376, suboccipital), blood (n = 158, femoral vein), and urine (n = 101, at autopsy). (See Table 1 for causes of death) All samples were stored at -80 degrees C. A further 100 samples of blood were later taken and stored at +4 degrees C before testing. Biochemical determinations made were: glucose in CSF, blood, and urine (hexokinase method); lactate (LDH/GPT) and free acetone (HS-gas chromatography) in CSF; hemoglobin A1 in blood (microcolumn technique). In 34 cases fatal diabetic coma was considered verified by morphological and chemical findings. One hundred cases of sudden cardiac death were chosen as the main control group. In 32 of the 34 cases defined above, the value of the formula of Traub (glucose + lactate in CSF) exceeded 415 mg/dl. It is not influenced significantly by hyperglycemia or hyperlactatemia due to factors other than diabetes (i.e., carbon monoxide, asphyxia). After death the value rose till the 30th hpm, then remained stable for at least 1 week. Fatal coma was defined as the ketoacidotic form if free acetone in CSF ranged above 21 mg/l. In these cases, CSF glucose and free acetone correlated positively. Hemoglobin A1 remained stable after death. Its amount was independent from postmortem blood glucose, postmortem interval and total hemoglobin. Furthermore, the manner of storage (-80 degrees or +4 degrees C) had no significant influence on its values. In 29 of 34 cases of fatal coma, Hb A1 exceeded 12.1%. Analysis of urine glucose showed elevated levels (over 500 mg/dl) in diabetic comas. On conclusion, fatal diabetic coma seems indicated as the cause of death if measured values of postmortem biochemistry exceed the following limits: CSF-Traub 415 mg/dl, free acetone (CSF) 21 mg/l; Hb A1 12.1%; urine glucose 500 mg/dl. Most important are the Traub formula and hemoglobin A1. Usually, in fatal coma both values are elevated. If both of them are normal, diabetic coma can nearly be excluded. Combined evaluation of all values is absolutely necessary. Morphology must also always be taken into account. Consequently, a diagnosis of fatal coma can be obtained by a process of elimination.     

Postmortem vitreous humor beta-hydroxybutyrate: its utility for the postmortem interpretation of diabetes mellitus

Ketoacidotic coma is one of the most serious complications arising from diabetes mellitus, especially type I, and may be the cause of sudden death especially in diabetes type I. Since beta-hydroxybutyrate (beta-OHB) serum concentrations might provide more information on the severity of ketoacidosis, the aim of this study was to evaluate the concentrations of beta-OHB in vitreous humor and its correlation with other biochemical parameters during postmortem examination. We intended to ascertain the sensitivity and the specificity of these markers for diagnosing diabetes mellitus and the presence of ketoacidosis. This study involved 453 cadavers with a mean age of 57.6 years (S.D. 20.7) and a mean postmortem interval of 17.8 h (S.D. 9.6, range 2-61 h). Cases were assigned to two diagnostic groups according to the antemortem diagnosis of diabetes mellitus, based on the patients' medical records. In vitreous humor statistically significant differences were found in biochemical marker concentrations between the two diagnostic groups, the highest values being obtained in the group of subjects with a previous diagnosis of diabetes mellitus. The measurement of beta-OHB in vitreous humor may be a useful alternative to using blood during postmortem analysis. The presence of high levels of beta-OHB may help interpret the cause of death in diabetics when the autopsy result is negative.     

Fatality from olanzapine induced hyperglycemia

A case history of a 31-year-old male schizophrenic patient is presented. The man was treated with olanzapine for three weeks before he died. After one week on a 10 mg daily dose of olanzapine, his fasting blood glucose was elevated to 11.3 mmol/L (203 mg/dL). In order to treat more aggressively his psychosis, the olanzapine dose was raised to 20 mg daily resulting in his fasting blood glucose climbing to 15.8 mmol/l (284 mg/dL). On the days preceding his death, he became progressively weaker, and developed polydipsia with polyuria. He had no personal or family history of diabetes mellitus and he was on no other medication at the time of his death. Postmortem blood, vitreous humor, and urine glucose concentrations were 53 mmol/L (954 mg/dL), 49 mmol/L (882 mg/dL), and 329 mmol/L (5922 mg/dL), respectively. Drug screen on urine and blood indicated only a small amount or olanzapine and no alcohols. Peripheral blood olanzapine concentration was within therapeutic limits, 45 ng/mL. Analysis of vitreous humor and urine revealed severe dehydration with small amounts of ketones. Death was attributed to hyperosmolar nonketotic diabetic coma, and olanzapine was felt most likely to be the cause. Another atypical neuroleptic, clozapine, has also been associated with the development and exacerbation of diabetes mellitus or diabetic ketoacidosis. We recommend including vitreous glucose and beta-hydroxybutyrate analysis as part of postmortem toxicology work up when the drug screen reveals the presence of either olanzapine or clozapine.     

Serum concentrations of cardiac troponin T in sudden death

Ischemic heart disease is the most common cause of sudden death of natural causes in most western countries. By autopsy, there may be no gross or histologic evidence of acute myocardial damage unless the patient survived for several hours following the event. Cardiac troponin in serum has become the recommended biochemical marker for myocardial injury in the clinical setting. We performed a prospective study on 102 autopsied subjects at the Central Hospital of Rogaland, Stavanger, Norway. Femoral blood was sampled for subsequent analysis of cardiac troponin T (cTnT). In the subjects with morphologic evidence of recent myocardial injury (n = 34), the mean serum cTnT level was 1.95 microg/L compared with 0.16 microg/L in the subjects with a noncardiac cause of death (n = 35) and 0.61 microg/L in the group with probable sudden cardiac death without morphologic signs of acute myocardial injury (n = 33). The observed differences in mean serum cTnT levels between the groups were statistically significant (P < 0.0001). These data suggest that elevated postmortem serum concentration of cTnT reflects ongoing myocardial damage and may support a diagnosis of cardiac-related death in cases associated with sparse or inconclusive morphologic findings postmortem.     

Postmortem Distribution of 3‐Beta‐Hydroxybutyrate

The concentrations of 3‐beta‐hydroxybutyrate (3HB) in femoral blood, urine, vitreous humor as well as pericardial and cerebrospinal fluids were retrospectively examined in a series of medico‐legal autopsies, which included cases of diabetic ketoacidosis, hypothermia fatalities without ethanol in blood, bodies presenting mild decompositional changes, and sudden deaths in chronic alcoholics. Similar increases in 3HB concentrations were observed in blood, vitreous, and pericardial fluid, irrespective of the cause of death, suggesting that pericardial fluid and vitreous can both be used as alternatives to blood for postmortem 3HB determination. Urine 3HB levels were higher than blood values in most cases. Cerebrospinal fluid 3HB levels were generally lower than concentrations in blood and proved to be diagnostic of underlying metabolic disturbances only when significant increases occurred.     

Postmortem differential diagnostics of diabetic and alcoholic ketoacidosis

It was shown that ketoacidosis may be an immediate cause of death in subjects suffering chronic alcoholic intoxication. The authors present a list of biochemical studies and parameters that can be used for differential diagnosis between diabetic and alcoholic ketoacidosis.     

Septic Ketoacidosis—A Potentially Lethal Entity with Renal Tubular Epithelial Vacuolization

Fatal ketoacidosis due to diabetes mellitus, alcoholism, and starvation may produce characteristic basal vacuolization of renal tubular epithelial cells (RTEC). Septic ketoacidosis has recently been recognized clinically as a distinct condition in which septicemia can lead to elevation of ketones and various anions unrelated to diabetes mellitus, alcoholism, or caloric deprivation. We report four lethal cases with significantly elevated vitreous ketones secondary to sepsis and/or severe localized infection in individuals with no history of diabetes mellitus, alcoholism, or starvation. Three of four cases exhibited typical basal vacuolization of RTEC. We suggest that septic ketoacidosis is an appropriate cause of death in the forensic setting where sepsis or severe localized infection is found with significant ketoacidosis (β‐hydroxybutyrate > 5 mmol/L)—in the absence of diabetes mellitus, alcoholism, starvation, or other states associated with accelerated ketogenesis. The finding of basal vacuolization of RTEC in such cases provides morphological support for the underlying metabolic derangement.     

Fentanyl concentrations in 23 postmortem cases from the hennepin county medical examiner's office

The purpose of this study was to compare blood fentanyl concentrations in fentanyl-related deaths with fentanyl concentrations found incidentally at autopsy, as well as with fentanyl concentrations found in hospitalized patients receiving fentanyl. Between the years 1997 to 2005, 23 fentanyl-positive postmortem cases were identified. Nineteen of 23 (82.6%) cases were deemed to be drug overdoses. Fentanyl alone was responsible for 8 of the 19 (42.1%) overdose deaths. Mean and median fentanyl concentrations were 36 (SD 38) microg/L and 22 microg/L, respectively, range 5-120 microg/L. Seven of the cases were accidental, one undetermined. The remaining 11 of the 19 (57.9%) cases were mixed drug overdoses. Fentanyl concentrations in these cases were 31 (SD 46) microg/L, range 5-152 microg/L. All of the mixed drug overdoses were determined to be accidental. Four cases where fentanyl was considered an incidental postmortem finding were determined to be natural deaths. In hospitalized inpatients (n = 11) receiving fentanyl 2 of the patients receiving fentanyl for chronic pain for more than 3 months had concentrations of 8.5 microg/L and 9.9 microg/L. The other nine inpatient concentrations were less than 4 microg/L. In conclusion, blood fentanyl concentrations found in cases where fentanyl alone was determined to be the cause of death were similar to cases where fentanyl was part of a mixed drug overdose. There was also considerable overlap between fentanyl concentrations in fentanyl-related overdose deaths compared to hospitalized patients being treated for chronic pain. Fentanyl concentrations in postmortem cases must be interpreted in the context of the deceased's past medical history and autopsy findings.     

Basal Vacuolization in Renal Tubular Epithelial Cells at Autopsy and Their Relation to Ketoacidosis

Basal vacuolization of renal tubular epithelial cells is a useful postmortem marker for ketoacidosis. To investigate its incidence and relationship to the severity of ketoacidosis, 158 autopsy cases with elevated β‐hydroxybutyrate (>1 mmol/L) over a 7‐year‐period were retrospectively reviewed. Sixty‐eight cases (43%) exhibited basal vacuolizations (vitreous β‐hydroxybutyrate: 1.16–29.35 mmol/L, mean 10.28 mmol/L), and 90 cases (57%) did not (vitreous β‐hydroxybutyrate: 1.03–13.7 mmol/L, mean 2.84 mmol/L). Quantitative analysis revealed on average a fourfold elevation in β‐hydroxybutyrate in cases with basal vacuolizations compared to those without; 10.3% of cases with β‐hydroxybutyrate concentrations between 1.01 and 2.00 mmol/L had basal vacuolizations, and this incidence increased to 33.3% with concentrations between 4.01 and 6.00 mmol/L. A marked increase in incidence to >70% was observed with concentrations >6.00 mmol/L, and basal vacuoles were invariably present (100%) with concentrations >14.01 mmol/L. This study demonstrates that basal vacuolizations are a sensitive marker for significant ketoacidosis and reaffirms its use as an indicator for likely cases of fatal ketoacidosis at autopsy.     

Tissue distribution of tramadol and metabolites in an overdose fatality

Tramadol (Ultram) is a centrally acting, synthetic analgesic agent. Although it has some affinity for the opiate receptors, tramadol is believed to exert its analgesic effect by inhibiting the re-uptake of norepinephrine and serotonin. There are several published cases of tramadol's involvement in drug-related deaths and impairment. Reports of deaths involving tramadol alone with associated tissue concentrations are rare. This report documents a case in which tramadol overdose was identified as the cause of death. The following tramadol concentrations were found in various tissues: blood, 20 mg/L; urine, 110.2 mg/L; liver, 68.9 mg/kg; and kidney, 37.5 mg/kg. Tissue distributions of the two primary metabolites, N-desmethyl and O-desmethyl tramadol, are also reported. In each tissue or fluid except urine, the tramadol concentration was greater than either metabolite, consistent with other reports of drug-impaired drivers and postmortem cases. The O-desmethyl metabolite concentration was greater than the N-desmethyl metabolite concentration in all tissues; this is in contrast to other postmortem reports, in which the majority of cases report concentrations of O-desmethyl as less than those of N-desmethyl. This may be useful as an indicator of time lapse between ingestion and death.     

The role of environmental factors in the causation of sudden death in infants: two cases of sudden unexpected death in two unrelated infants who were cared for by the same babysitter

We report two cases of sudden unexpected death in two unrelated African American female infants, 2 months and 4 months old. Both infants were attended to by the same babysitter in the same apartment and died 39 days apart in the same bed and in the same bedroom. The autopsy of the first infant revealed sudden unexplained death in an infant. Toxicologic analysis for carbon monoxide (CO) was not performed because it was not suspected. When the second infant died, investigation into the ambient air quality within the apartment revealed high levels of CO emanating from a poorly ventilated and defective hot water heater, which was located across a hallway from the bedroom where the two babies died. CO saturation levels in the postmortem blood samples of the two babies were elevated and were similar (13% and 14%). Nicotine and cotinine were not detected in the blood sample of the two infants. Cherry-red livor mortis was absent. Acute CO intoxication was determined to be the underlying cause of these two unexpected deaths. These two cases underscore the need to integrate ambient air analysis and postmortem CO analysis as routine components of the comprehensive death investigation of infants who die suddenly and unexpectedly.