Timothy R. Wolfe

Massive dextromethorphan ingestion and abuse

The case of a 23-year-old man who was acutely intoxicated on dextromethorphan and who was chronically addicted to the drug is described. He consumed the highest daily dose for the longest duration yet reported in the worlds English-language medical literature. Toxicity, abuse potential, and therapy of dextromethorphan intoxication are discussed.

Terminal 40-ms frontal plane QRS axis as a marker for tricyclic antidepressant overdose

Tricyclic antidepressant (TCA) poisoning has been reported to cause a right-axis deviation of 130 degrees to 270 degrees in the terminal 40-ms frontal plane QRS axis (T40-ms axis) of the ECG. This retrospective cohort study was designed to determine if the T40-ms axis could discriminate TCA-toxic patients from other overdose patients and whether a correlation exists between TCA plasma concentration and T40-ms axis rotation. Only symptomatic overdose patients with plasma and urine drug screens and an ECG obtained within two hours of each other were included in the study. Patients were divided into two groups: TCA overdose patients (TCA OD, n = 48) and nonTCA overdose patients (nonTCA OD, n = 30). The mean T40-ms axis was significantly more rightward in the TCA OD group compared with the nonTCA OD group (179 +/- 74 vs 86 +/- 87, P less than .001). A TCA OD patient was 8.6 times more likely to have a T40-ms axis of more than 120 degrees than was a nonTCA OD patient (odds ratio, 8.6; 95% confidence interval, 2.7 to 29.1). Eight of the TCA poisoned patients (17%) did not demonstrate a T40-ms axis between 120 degrees and 270 degrees. Receiver operating characteristics demonstrated that the T40-ms axis was a better indicator of TCA toxicity than the QRS interval (P less than .05). A T40-ms axis of 120 degrees or more was 83% sensitive and 63% specific for TCA overdose. A correlation between plasma TCA concentration and T40-ms axis deviation was not found (r = .04).(ABSTRACT TRUNCATED AT 250 WORDS)

SYNCOPE AS AN EMERGENCY DEPARTMENT PRESENTATION OF PULMONARY EMBOLISM

Pulmonary embolism presenting as an isolated syncopal spell can be a difficult clinical correlation to make. We present three cases of pulmonary embolism-induced syncope and review the pathophysiology and diagnostic considerations in this setting. Pulmonary embolism should be considered in the differential diagnosis of every syncopal event that presents to the emergency department, even in the face of cardiac dysrhythmias and normal pulse oximetry values.

The comparative risks of bacterial contamination between a venturi atomizer and a positive displacement atomizer.

Introduction This laboratory study determined the incidence of internal contamination of Venturi principle atomizers and positive displacement atomizers exposed to high external concentrations of Staphylococcal aureus (Staph). Methods Atomizer device nozzle tips were immersed into a Staph solution and 1 ml of spray was atomized via compressed wall air (Venturi) or hydraulic pump (positive displacement). The Venturi nozzle was then wiped with 70% isopropyl alcohol while the disposable positive displacement nozzle was replaced. After 30 minutes, 1 ml of atomized fluid was collected and cultured and the process was repeated. After sixteen uses the fluid remaining in the bottles was cultured. The Venturi atomizer also was subjected to a single use trial to determine the location of device contamination. Results Venturi atomizers sprays grew Staph in every case (144/144), while positive displacement atomizer sprays never grew contaminants (0/144; p < 0.0001). At the end of 16 uses, 7/9 of Venturi atomizers had Staph within their medication reservoirs while none (0/9; p = 0.002) existed in the positive displacement atomizers. After a single use of the Venturi atomizer, the medication reservoir, the air lumen and the medication lumen of the nozzle were all contaminated with Staph. Conclusions External bacterial contamination of the atomizer nozzle tip results in internal bacterial contamination of Venturi devices in as little as one use but not of positive displacement devices. These results warrant further investigation to determine whether a risk of cross-contamination exists in a clinical setting.

A comparison of infusion volumes in the measurement of intra-abdominal pressure

Bladder pressure measurement through a foley catheter is the current standard in monitoring for intraabdominal hypertension (IAH) and abdominal compartment syndrome (ACS). Accurate pressure transduction requires a continuous fluid column with a small volume of transducing medium at the tip of the catheter. Infusing excessive fluid volume can falsely elevate the measured intra-abdominal pressure (IAP) due to bladder overdistention and can lead to intrinsic muscular contraction. This effect can be seen with volumes as low as 60 mL. Recent expert consensus has recommended 25 mL as the maximal infusion volume; however, 50 mL is the most commonly cited volume of infusion in the literature. The purpose of this analysis was to determine the variance between IAP values using a range of volume infusions between 10 and 60 mL. Eighteen adult, surgical intensive care unit (SICU) patients who were undergoing IAP measurement for IAH or clinically indicated monitoring were enrolled in a prospective, nontreatment study. Intra-abdominal pressure measurements were obtained with stepwise increases of injectate volume from 10 to 60 mL (in 10 mL increments). Bland-Altman analyses and receiver operating characteristic (ROC) curves were used for analysis. After analysis accounting for data correlation within patients, means and standard deviations were generated for differences between 50 mL and 10, 20, 30, 40, and 60 mL bladder infusion volumes. Bland-Altman analyses showed good agreement between measurements and no significant difference in variance (mean ≤1.35 mm Hg) between volume comparisons. The ROC curve generated for each test volume using a diagnostic pressure value for IAH (!12 mm Hg) showed that a value between 11 and 12 mm Hg gave the best combination of sensitivity and specificity for all test volumes. In SICU patients, with a clinical indication for IAP monitoring, bladder infusion volumes between 10 mL and 60 mL provide consistent IAP measurements.

Evaluation of an electronic esophageal detector device in patients with morbid obesity and pulmonary failure

Objective. Undetected esophageal intubation can result in permanent injury or death. Clinical confirmation of tube location may be misleading. Adjunctive methods should be used to supplement clinical judgment. Unfortunately, end-tidal carbon dioxide may misidentify properly placed tracheal tubes in low perfusion situations, while esophageal detector devices (EDDs) may misidentify properly placed tracheal tubes in situations where little airway dead space exists (morbid obesity, pulmonary failure). This study evaluated a modified EDD (the electronic esophageal detector device, or EEDD) designed to eliminate the problem of misidentified tracheal intubations. Methods. Intubated morbidly obese or pulmonary failure patients were eligible for study entry. All endotracheal tubes (ETTs) were confirmed to be tracheal by waveform capnography and clinical judgment prior to study entry. Following consent, all patients were attached to the EEDD and a “measurement” was made to determine the “location” of their ETTs. Probability of misidentifying a tracheal intubation in these high-risk populations was calculated using a log-normal distribution method. Results. Twenty-seven morbidly obese patients and 37 pulmonary failure patients were entered. The EEDD correctly identified all tracheal intubations in these patients, giving a false-negative rate of zero. The probability of misidentifying a tracheal intubation in the combined group was 0.06%. Conclusion. This study demonstrates that the EEDD reliably identifies tracheal intubations in situations where standard EDDs may fail. However, future studies must determine the reliability of this device for identification of esophageal intubations and the reliability of this device in the less controlled emergency department and prehospital settings.

Ruptured renal angiomyolipoma presenting as renal colic

The case of a patient with acute onset of flank pain and hematuria is presented. Initial therapy was directed toward relief of pain believed to be caused by renal colic. It was not until the patient developed atypical features that the true diagnosis, ruptured renal angiomyolipoma, was discovered. The case and discussion emphasize the need to carefully consider a complete differential diagnosis when evaluating patients with flank pain and hematuria who have atypical clinical features or an atypical course.