David Hung-Tsang Yen

The clinical experience of acute cyanide poisoning.

The authors reviewed the clinical manifestations, complications, and the prognosis affected by Lilly Cyanide Antidote in 21 victims of acute cyanide poisoning over a 10-year period. The clinical signs and symptoms in cyanide poisoning are variable. Among 21 cases, loss of consciousness (15), metabolic acidosis (14), and cardiopulmonary failure (9) were the three leading manifestations of cyanide intoxication. Anoxic encephalopathy (6) was not uncommon in the severely intoxicated victims. Diabetes insipidus (1) or clinical signs and symptoms mimicking diabetes insipidus (3) may be an ominous sign to encephalopathy victims. The major cause of fatal cyanide poisoning is the intentional ingestion of cyanide compounds as part of a suicide attempt. Decrease of arteriovenous difference of O2 partial pressure may be a clue for the suspicion of cyanide intoxication. Although the authors cannot show a statistically significant difference (P = .47) for the Lilly cyanide antidote kit in terms of improving the survival rate for victims of cyanide poisoning, the antidote kit was always mandatory in our study in the cases of severely intoxicated victims who survived. Early diagnosis, prompt, intensive therapy with antidote, and supportive care are still the golden rules for the treatment of acute cyanide poisoning, whether in the ED or on the scene.

Spectral analysis of systemic arterial pressure and heart rate signals of patients with acute respiratory failure induced by severe organophosphate poisoning.

ObjectiveSpectral analysis of systemic arterial pressure (BP) and heart rate (HR) signals may be an alternative prognostic tool for predicting patient outcome in the intensive care unit (ICU). We evaluated the applicability of the same analysis in the emergency department for predicting mortality in patients with acute respiratory failure induced by severe organophosphate poisoning. DesignProspective collection of data from 14 emergency service patients. SettingEmergency service at a large, university-affiliated medical center. PatientsConsecutive patients who, after attempting suicide by ingesting organophosphates, were admitted to the ICU of the emergency service with acute respiratory failure and remained for ≥2 days InterventionsNone. Measurements and Main ResultsDemographic and survival data and day 1 Acute Physiology and Chronic Health Evaluation (APACHE) II and Glasgow Coma Scale scores were recorded. Continuous, on-line, real-time spectral analysis of BP and HR signals was carried out during the first 12 hrs after admission. We then computed the total sum of power density during this period of the low-frequency (0.04–0.15 Hz) and very low-frequency (0.004–0.04 Hz) components in the BP and HR spectra, along with the averaged values of mean BP and HR. Eight patients who recovered exhibited vigorous power in the low-frequency and very low-frequency components of their BP and HR signals. There was a significant reduction in the power density of those four spectral components in three patients who eventually died. Three patients discharged in a vegetative state manifested significantly reduced power in the low-frequency component in their BP spectra, with maintained power in the other three spectral components. APACHE II and Glasgow Coma Scale scores of the recovered patients were discernibly different from those of patients who eventually died or who became vegetative. None of the 14 patients showed appreciable differences in mean BP, mean HR, erythrocyte or plasma cholinesterase concentration, or atropine requirement during the first 24 hrs. ConclusionThe low-frequency and very low-frequency components of BP and HR signals may be a sensitive alternative index for early prediction of mortality in patients with acute respiratory failure induced by severe organophosphate poisoning.

Seroprevalence of Antibodies to Pandemic (H1N1) 2009 Influenza Virus Among Hospital Staff in a Medical Center in Taiwan

Background: The pandemic (H1N1) 2009 influenza emerged in April 2009 and spread rapidly and broadly all over the world. In addition to specific antiviral agents, massive vaccination is thought to be the most effective way of controlling the transmission. To understand the prevaccination status of certain risk groups, this study compared the baseline sero‐prevalence of antibodies to the pandemic (H1N1) 2009 influenza virus among hospital staff with different contact risks and that of the general population. Methods: A total of 295 serum samples from hospital staff and 244 control serum samples from people who came for physical check‐up (control group) were collected between October 2009 and November 2009 before the massive vaccination campaign. The hospital staff was divided into first‐line risk personnel (group 1) and second‐line risk personnel (group 2) according to their potential contact risks. Hemagglutination‐inhibition (HI) tests were conducted to determine the individual serological status. The seropositive rate (SPR, defined as the proportion with HI titer ≥ 1:40) of antibodies to H1N1 influenza virus and its geometric mean titer (GMT) were calculated and compared among the different groups. Results: The mean ages and sex ratio (% male) of the hospital staff and control groups were 36.9 ± 10.6 years and 52.0 ± 12.6 years, and 24.4% and 57.6%, respectively. The SPR of the antibodies to H1N1 influenza virus of the hospital staff was significantly higher than that of the control group (20.0% vs. 2.9%, p < 0.001). Furthermore, the SPR antibodies to H1N1 influenza virus of group 1 were significantly higher than that of group 2 (30.8% vs. 12.6%, p < 0.001). However, the GMT of antibodies to H1N1 influenza virus of the hospital staff was not significantly different from that of the control group (p = 0.925). Conclusion: The SPR of antibodies against the pandemic (H1N1) 2009 virus in the hospital staff was higher than that in the general population, reflecting a higher contact risk. Prevaccination surveillance of the immune status of different risk groups may help to prioritize which groups should be vaccinated first.

Renal abscess: Early diagnosis and treatment

The purpose of this study was to identify initial clinical characteristics that can lead to early diagnosis of renal abscess in the emergency department and predict poor prognosis. A retrospective review of 88 renal abscess patients, from April 1979 through January 1996, was conducted. Patients were categorized into two groups. In group 1, renal abscess was diagnosed by an emergency physician, whereas in group 2 renal abscess was not diagnosed by an emergency physician. Clinical characteristics included demographic data, predisposing medical problems, duration of illness before diagnosis, time spent in hospital diagnosis, initial signs and symptoms, laboratory tests, and radiology studies that may have been useful in the early diagnostic regimes. Clinical factors were also analyzed for their value in predicting poor prognosis. The mean age of 88 patients with renal abscess was 59.8 years. The most common predisposing disorder was diabetes mellitus, followed by renal calculi and ureteral obstruction. The duration of diagnosis by emergency physicians was shorter for group 1 patients (1.2 +/- .4 v group 2, 2.8 +/- 2.9 days; P < .01) and the blood urea nitrogen level was higher in group 1 (55.7 +/- 42.2 mg/dL, v group 2, 33.5 +/- 33.5 mg/dL; P = .02). In the early diagnosis of renal abscess, emergency physicians should focus on patients who have predisposing disorders, ie, diabetes mellitus, renal stones, immunosuppression, longer duration of symptoms of urinary tract infection, and renal failure, who should promptly be investigated with ultrasound in the emergency department. The cure rate after treatment with routine antibiotics plus percutaneous drainage was 64%. This therapy is recommended for initial treatment. Poor prognosis is associated with elderly patients with lethargy and with elevation of the serum blood urea nitrogen level.

Elderly use of the ED in an Asian metropolis.

To compare emergency department (ED) use by elderly patients (age 65 yrs or older) with that by younger adult patients (age 15-64 yrs), a prospective consecutive chart review study was conducted from August 1, 1995 through May 31, 1996 in eight designated hospitals in Taipei city (which has 2.6 million residents, 8.4% of whom are 65 yrs or older). Patient age, sex, mode of arrival, living status, triage category, advanced life support (ALS) eligibility, referral, confinement to bed, intensive care unit (ICU) admission, impression, trauma mechanism, and disposition were recorded and compared between the two groups. Of 27,765 adult emergency patients studied during the 10 months, 24% were elderly. The elderly were more likely to be ambulance cases, of high acuity and ALS eligibility, living alone, bed-ridden, and ICU cases (19.4% v 10.5%, 14.8% v 5.5%, 14.7% v 4.3%, 9.7% v 4.1%, 16% v 1.1%, and 4.0 v 1.1%, respectively). The three leading illnesses in the elderly were cerebral vascular accident (6.6%), cancer (5.6%), and cardiovascular disease (5.6%), and the two most common trauma mechanisms were trip (fall from the same level surface) (57.2%) and traffic accident (20.7%). Twenty-seven percent and 22.7% of elderly were disposed to admission and observation, respectively, compared with the 10.9% and 11.4% of the younger patients. Elderly patients have significantly different and more severe presentations to the ED compared with younger adults.

Clinical Factors and Outcomes in Patients with Acute Mesenteric Ischemia in the Emergency Department

Background: The purpose of this study was to determine the initial clinical characteristics of acute mesenteric ischemia and identify variables associated with adverse outcomes in the emergency department (ED). Methods: The charts of 124 consecutive patients with surgically and pathologically identified acute mesenteric ischemia from September 1990 to September 2000 were reviewed retrospectively to obtain data about demographics, initial clinical presentations, predisposing diseases, previous medications, laboratory tests, and common findings on computed tomography scans with contrast. Only patients admitted through the ED and treated on medical or surgical wards were enrolled. Results: Mean patient age was 71.1 years (range, 25‐100 years). The overall mortality rate was 50%. There were no significant differences in gender, underlying disease, previous medication, initial signs and symptoms, and causes of mesenteric infarction, between survivors and non‐survivors. Univariate analysis demonstrated that older age, bandemia, hepatic and renal impairment, hyperamylasemia, metabolic acidosis, hypoxia, intramural pneumatosis, and septic syndrome, were more frequent in patients who died than in those who survived (p < 0.05). Logistic regression identified the following variables as independent predictors of death: old age (odds ratio, OR, 1.077; 95% confidence interval, CI, 1.013, 1.146; p = 0.02); bandemia (OR, 3.894; 95% CI, 1.160, 13.074; p = 0.03); elevated serum aspartate aminotransferase (AST; OR, 4.532; 95% CI, 1.274, 16.122; p = 0.02); increased blood urea nitrogen (BUN; OR, 7.219; 95% CI, 1.166, 44.696; p = 0.03); and metabolic acidosis (OR, 6.604; 95% CI, 1.804, 24.171; p < 0.01). Conclusion: A high index of suspicion and aggressive diagnostic imaging can facilitate early diagnosis and improve outcomes for patients with acute mesenteric ischemia. Risk stratification showed that elderly patients with metabolic acidosis, bandemia, or elevated AST and BUN had a poor prognosis. Greater therapeutic intervention is advocated to reduce mortality in high‐risk patients with acute mesenteric ischemia.

Coenzyme Q10 confers cardiovascular protection against acute mevinphos intoxication by ameliorating bioenergetic failure and hypoxia in the rostral ventrolateral medulla of the rat

Coenzyme Q10 (CoQ10, ubiquinone) is a highly mobile electron carrier in the mitochondrial respiratory chain that also acts as an antioxidant. We evaluated the cardiovascular protective efficacy of CoQ10 at the rostral ventrolateral medulla (RVLM), a medullary site where sympathetic vasomotor tone originates and where the organophosphate poison mevinphos (Mev) acts to elicit cardiovascular intoxication. Experiments were carried out in adult male Sprague-Dawley rats that were maintained under propofol anesthesia. Microinjection bilaterally of Mev (10 nmol) into the RVLM induced progressive hypotension and minor bradycardia, alongside significant depression of the activity of NADH cytochrome c reductase (enzyme marker for Complexes I and III) or cytochrome c oxidase (enzyme marker for Complex IV) in the mitochondrial respiratory chain, reduction in ATP concentration, or tissue hypoxia in the RVLM. On the other hand, the activity of succinate cytochrome c reductase (enzyme marker for Complexes II and III) remained unaltered. The Mev-induced hypotension, bioenergetic failure, or hypoxia was significantly reversed when CoQ10 (4 μg) was coadministered bilaterally into the RVLM with the organophosphate poison. We conclude that CoQ10 confers cardiovascular protection against acute Mev intoxication by acting on the RVLM, whose neuronal activity is intimately related to the “life-and-death” process. We also showed that amelioration of the selective dysfunction of respiratory enzyme Complexes I and IV in the mitochondrial respiratory chain, the reduced ATP level, and the induced tissue hypoxia in the RVLM are among some of the underlying mechanisms for the elicited protection.

Spectral changes in systemic arterial pressure signals during acute mevinphos intoxication in the rat.

We investigated the cardiovascular consequences of acute intoxication by the organophosphate poison, mevinphos (Mev), and delineated the underlying mechanism. Based on on-line power spectral analysis of systemic arterial pressure (SAP) signals in rats anesthetized and maintained by propofol, we identified two distinct phases after intravenous administration of Mev (160 or 320 microg/kg). Phase I was characterized by transient hypertension and mild tachycardia, concurrent with an increase in the very high-frequency (BVHF; 5-9 Hz), high-frequency (BHF; 0.8-2.4 Hz), low-frequency (BLF; 0.25-0.8 Hz),and very low-frequency (BVLF; 0-0.25 Hz) components of SAP signals. Phase II exhibited significant hypotension, a reversal of the BVHF and BVLF power to control levels, and further reduction in the power density of both BHF and BLF components to below baseline. Microinjection of Mev (2 microg) into the bilateral nucleus reticularis ventrolateralis (NRVL), the medullary origin of sympathetic neurogenic vasomotor tone, essentially duplicated those phasic cardiovascular changes. Similarly, sympathoexcitatory NRVL neurons exhibited respectively an elevation and a decline in their spontaneous activities during Phase I and Phase II Mev intoxication. We conclude that the progressive accumulation of acetylcholine over time induced by a direct inhibition of Mev on cholinesterase in the NRVL may be responsible for the phasic changes in cardiovascular events over the course of acute Mev intoxication. Whereas the initial amount of acetylcholine is excitatory to NRVL neurons, overstimulation by the amassed acetylcholine results instead of an inhibitory action.

D-dimer in patients with suspected acute mesenteric ischemia.

OBJECTIVES The aims of this study were to assess the diagnostic value of D-dimer in patients with suspected acute mesenteric ischemia (AMI) and to evaluate the correlation between D-dimer levels and the severity of bowel necrosis. METHODS A prospective, noninterventional study of 67 patients with clinical suspicion of AMI was performed. Measurement of D-dimer levels was performed using a latex turbidimetric method. RESULTS Acute mesenteric ischemia was diagnosed in 23 patients (34.3%) and non-AMI in 44 patients (65.7%). Median D-dimer levels on admission were 6.24 microg fibrinogen equivalent units (FEU)/mL (range, 0.96-53.48 microg FEU/mL) in patients with AMI and 3.45 microg FEU/mL (range, 0.50-44.69 microg FEU/mL) in non-AMI patients (P = .064). D-dimer had poor discriminative value to differentiate the presence from the absence of AMI with an area under the receiver operating characteristic curve of 0.64 (95% confidence interval, 0.50-0.78). A serum D-dimer cutoff value of 1.0 microg FEU/mL had a sensitivity of 96%, a specificity of 18%, a positive likelihood ratio of 1.17, and a negative likelihood ratio of 0.24. Among patients with AMI verified at operation, 8 had resectable bowl necrosis and 9 had unresectable bowel necrosis. There was no difference in serum D-dimer levels between resectable and unresectable bowel necrosis (P = .665). CONCLUSIONS Detection of serum D-dimer could not help to differentiate patient with AMI from those with non-AMI. We did not find a correlation between serum D-dimer levels and the severity of AMI. However, measurement of D-dimer levels can be of value for a small decrease in the likelihood of AMI, when the result is low.

Arterial oxygen desaturation during emergent nonsedated upper gastrointestinal endoscopy in the emergency department

A prospective study was conducted to see whether emergent esophagogastroduodenoscopy (EGD) in patients with active upper gastrointestinal (GI) bleeding is associated with more oxygen desaturation than nonemergent EGD. Emergent EGD was performed in the study patients with active upper GI bleeding. Nonemergent EGD was performed in the control patients. Determination of oxygen saturation (Sao2) was measured by pulse oximeter. A decrease in Sao2 of > 4% was more frequent in the study patients (26%, 13 of 50) than in controls (6%, 3 of 50) (P < .01). During EGD, mean oxygen saturation decreased significantly in both groups of patients. After EGD, mean oxygen saturation did not recover toward the pre-endoscopy insertion level in the study group (P < .01). A linear association was found that oxygen desaturation = 5.46 + 0.15 (status) -0.06 (baseline oxygen saturation). Emergent EGD for active upper GI bleeding in the emergency department tends to be associated with more frequent significant oxygen desaturation than nonemergent EGD. Continuous oxygen supplementation and oxygen saturation monitoring may be used during emergent nonsedated EGD in the emergency department.