Evaluation of surgical performance with standard rigid and flexible-tip laparoscopes.

BACKGROUND: Flexible-tip laparoscopes have recently been introduced into clinical practice, with the goal of improving surgeon performance during complex laparoscopic procedures. We used objective and subjective performance parameters to compare standard rigid 0 degrees and 30 degrees lens laparoscopes two flexible-tip laparoscopes in an in vitro model. METHODS: Twenty-nine subjects with varied levels of surgical experience performed complex laparoscopic tasks in three different models simulating (a) prostate dissection from the rectum, (b) cystic duct clipping, and (c) distal posterior rectum dissection. Each task was performed using two Storz rigid laparoscopes (0 degrees and 30 degrees) and two flexible-tip laparoscopes, the Olympus LTF-V3 and the Fujinon EL2-TF310. The sequence of application of the two flexible-tip laparoscopes was randomized. In each case, an experienced laparoscopic camera driver controlled the field of vision. Time to complete each task, operative precision, and subjective surgeon rating scores were compared. Statistical analysis was performed with analysis of variance (ANOVA) and a two-sided fisher's exact test. RESULTS: In all three models, the flexible laparoscopes offered no advantage in terms of procedure time, surgical precision, or subjective surgeon rating score when compared with the 30 degrees lens rigid laparoscope. The 30 degrees rigid lens laparoscope and the two flexible-tip laparoscopes were superior to the 0 degrees lens rigid laparoscope for all parameters evaluated, with the exception of subjective rating in the cystic duct model and procedure time in the colorectal model. CONCLUSION: In this in vitro experimental model, the flexible-tip laparoscopes found to have no advantage over the standard rigid 30 degrees lens laparoscope. These models were validated, as the 0 degrees lens rigid laparoscope was surpassed by the 30 degrees lens rigid laparoscope and the flexible-tip laparoscopes. Both flexible-tip laparoscopes produced similar results and excellent image quality, but some experience is required before their smooth application can be achieved.

Encephalopathy and peripheral neuropathy following diethylene glycol ingestion.

The authors report a 24-year-old man who developed encephalopathy and rapid quadriplegia following ingestion of a solution containing diethylene glycol (DEG). As quadriparesis evolved, motor response amplitudes were markedly reduced with preserved conduction velocities. Studies during clinical recovery revealed marked motor conduction velocity slowing and prolonged distal latencies. These data indicate that DEG intoxication may cause a primary acute axonal sensorimotor polyneuropathy with demyelinating physiology during recovery.

Results of laparoscopic Heller-Toupet operation for achalasia.

BACKGROUND: Laparoscopic myotomy has become the preferred treatment for achalasia. Controversy persists on the need for fundoplication and/or its type; when used, most series have utilized the Dor fundoplication. We report a large series of laparoscopic Heller-Toupet procedures. METHODS: All patients operated for achalasia were entered into a prospective database. Pre and postoperative esophageal symptoms, satisfaction scores, and SF-36 variables were compared. Surgical failures were defined as recurrent or persistent dysphagia leading to secondary treatment. Data are expressed as mean +/- S.D. RESULTS: One hundred consecutive cases were analyzed (61 men, 39 women, age 47 +/- 17 yr). Heller-Toupet was performed in 94, whereas six patients had a Dor fundoplication because of mucosal perforation (three) or technical difficulties performing a posterior wrap (three). Operative time was 148 +/- 21 min. There were 13 intraoperative adverse events managed laparoscopically, and no conversions. Minor postoperative complications were noted in two cases, whereas there were no major complications or deaths. Mean hospital stay was 1.2 +/- 0.5 days, (range 1-4). Follow-up was complete in 92% at 26 +/- 17 months. Failures leading to further treatment occurred in 4%. All symptom scores were significantly improved (p < 0.0001). Solid dysphagia score went from 6.4 to 1.0 postoperatively; regurgitation score went from 4.5 to 0.2 (combined frequency and severity, range 0-8). Postoperative global esophageal symptoms scale revealed improvement in 97%, and all domains of the SF-36 were improved. CONCLUSIONS: Although the best surgical approach to achalasia is yet to be determined, laparoscopic Heller-Toupet operation in experienced hands is a safe and effective procedure with low rates of morbidity and failure and high patient satisfaction.

Aldicarb poisoning by an illicit rodenticide imported into the United States: Tres Pasitos.

OBJECTIVE: Although intentional and unintentional rodenticide poisoning is common, most readily available agents are of relatively low acute toxicity. A four-year long epidemic of severe toxicity from rodenticide exposure continues among patients predominantly of Dominican descent living in New York City. This study characterizes the ongoing epidemic of acute cholinesterase inhibitor poisoning due to an illicit rodenticide and identifies its etiology. METHODS: A prospectively collected case series of poisoned patients referred to the New York City Poison Control Center. The main outcome measures include the clinical characteristics upon presentation, antidotal and other therapeutic requirements, and patient outcome. Product analysis was performed with paper chromatography, gas chromatography/mass spectrometry, and high-performance liquid chromatography. A murine model assessing both clinical effect and cholinesterase activity was also performed. RESULTS: Thirty-five patients were referred following exposure to Tres Pasitos. Patients developed signs of cholinergic hyperactivity and many required high doses of atropine (>10 mg) to control these symptoms. The source was identified as a rodenticidal compound sold illicitly in local groceries primarily within the Dominican community. Murine cholinesterase activity fell significantly following exposure to the rodenticide. High-performance liquid chromatography identified aldicarb, an extremely potent carbamate-type cholinesterase inhibitor, not licensed for rodenticidal use in this country. CONCLUSION: Illicit sale of undocumented compounds poses a substantial public health threat. Despite several public health interventions, the epidemic continues.

Speed skills: measuring the visual speed analyzing properties of primate MT neurons.

Knowing the direction and speed of moving objects is often critical for survival. However, it is poorly understood how cortical neurons process the speed of image movement. Here we tested MT neurons using moving sine-wave gratings of different spatial and temporal frequencies, and mapped out the neurons' spatiotemporal frequency response profiles. The maps typically had oriented ridges of peak sensitivity as expected for speed-tuned neurons. The preferred speed estimate, derived from the orientation of the maps, corresponded well to the preferred speed when moving bars were presented. Thus, our data demonstrate that MT neurons are truly sensitive to the object speed. These findings indicate that MT is not only a key structure in the analysis of direction of motion and depth perception, but also in the analysis of object speed.

Twenty-foot fall averts fatality from massive hydrogen sulfide exposure.

Hydrogen sulfide is a colorless irritant and asphyxiant gas with a noxious odor of "rotten eggs." Acute hydrogen sulfide exposure may cause, depending on the level and duration of toxicity, symptoms ranging from mild mucous membrane irritation to permanent neurologic impairment and cardiopulmonary arrest. We present a case of an oil refinery worker exposed to a typically fatal concentration of hydrogen sulfide gas (>1000 ppm) while working on top of a 20-foot ladder. The "knockdown" effect of exposure to high concentrations of hydrogen sulfide caused him to lose consciousness and fall from the top of the ladder. He was transported to the Emergency Department as a major trauma victim. Ironically, this 20-foot fall saved his life and possibly those of the rescuers by immediately removing him from the source of the hydrogen sulfide. Treatment of hazardous materials incidents and the pathophysiology and treatment options for hydrogen sulfide poisoning are discussed.

Drug screening versus history in detection of substance use in ED psychiatric patients.

Because self-reporting of substance use may not be reliable, physicians rely on drug screening. We tested the hypothesis that drug screening alone is sufficient to detect substance use in ED psychiatric patients. We prospectively evaluated patients receiving psychiatric consultation over 6 months ending in April 1998 in an urban medical/psychiatric ED with 42,000 annual visits. After informed consent, patients underwent a structured interview by trained research associates who queried regarding substance use in the past 3 days. This self-report was compared with urine drug screen results for 11 substances of abuse. Standard descriptive statistical techniques were used. Kappa statistics were used to assess concordance between history and drug screens. Two hundred eighteen patients participated, 124 had a urine drug screen obtained. Patients with and without urine drug screens were similar with respect to age (34.9 versus 34.9 years, P =.3) and psychiatric diagnosis (P =.24). Overall, there was only fair concordance between history and drug screens (kappa = 0.46). History alone detected substance use in 70 patients (57%); drug screening alone detected substance use in 77 patients (62%). The combination of history and drug screening more often detected substance use than either alone (90 pts (73%); P <.05 for both comparisons). Depending on the particular drug, there was wide variation in concordance between history and drug screen (kappa's varied from 0.07 for ethanol to 0. 79 for cocaine). History was better than drug screening for ethanol use (40 versus 10 patients), and THC (28 versus 15 pts). Drug testing alone was never significantly better than history. Although self-reporting of substance use is not reliable, reliance on drug screening alone is also flawed. Optimal identification of drug use in emergency department psychiatric patients requires both history and drug screening.

Chronic salicylism resulting in noncardiogenic pulmonary edema requiring hemodialysis.

Salicylate intoxication is frequently overlooked as a cause of noncardiogenic pulmonary edema and altered mental status in adult patients. We describe a 42-year-old woman who presented with two episodes of recurrent noncardiogenic pulmonary edema requiring intubation. The first admission to hospital triggered an extensive initial workup that did not indicate a cause for the pulmonary edema. At the second presentation, recognition of the clinical syndrome in the emergency department led to the correct diagnosis of salicylate intoxication. The patient was successfully treated with hemodialysis and urinary alkalinization, leading to rapid resolution of pulmonary edema and extubation. Several aspects of the clinical presentation suggest that the patient suffers from chronic salicylism, probably complicated by episodic superimposed acute intoxication, a condition often misdiagnosed or diagnosed late in the course of disease, contributing to substantial morbidity and mortality in these patients. Maintenance of a high index of suspicion and rapid institution of appropriate therapy including hemodialysis once the diagnosis is established is an important determinant of outcome in this serious but underdiagnosed disorder.

Randomized, double-blind, placebo-controlled trial of diazepam, nitroglycerin, or both for treatment of patients with potential cocaine-associated acute coronary syndromes.

INTRODUCTION: To the authors' knowledge, treatment of patients with cocaine-associated acute coronary syndromes has not been rigorously investigated in symptomatic patients. OBJECTIVE: To perform a randomized double-blind trial of diazepam, nitroglycerin, or both for treatment of patients with potential cocaine-associated acute coronary syndromes. METHODS: Patients with potential cocaine-associated acute coronary syndromes were randomized to treatment with either diazepam, nitroglycerin, or both every 5 minutes or until symptom resolution. Outcomes were chest pain resolution (measured by visual analog scale), and changes in blood pressure, pulse rate, cardiac output (L/min), cardiac index (L/min/m2), stroke volume (mL/beat), and stroke index (mL/beat/m2) over the 15-minute treatment period. To adjust for seven outcomes using the Bonferroni correction, alpha was set at 0.007. RESULTS: Forty patients were enrolled (diazepam, 12; nitroglycerin, 13; both, 15). Patients had a mean age (+/-SD) of 35.4 (+/-7.5) years; 75% were male. They presented a mean of 5 hours and 37 minutes after cocaine use. Baseline demographics, cocaine use patterns, chest pain characteristics, and initial electrocardiograms were similar for all groups. Chest pain severity improved similarly in the three groups [-33.3 mm (+/-8.0); -30.7 mm (+/-7.1); -33.0 mm (+/-7.9); p = 0.6]. The stroke index decreased during the 15-minute treatment period for all groups (diazepam, -8.7 (+/-3.3); nitroglycerin, -3.1 +/- 2.8; both, -1.8 (+/-3.1) mL/beat/m2; p = 0.03). After adjustment for differences between baseline hemodynamic and cardiac profiles and multiple comparisons, there was no difference in any response to therapy over time for the different treatments. CONCLUSIONS: For treatment of patients with potential cocaine-associated acute coronary syndromes, chest pain resolutions and changes in cardiac performance are not different in patients treated with diazepam or nitroglycerin. In this study, the use of both agents did not offer any advantage over either agent alone.

Cardiac and hemodynamic assessment of patients with cocaine-associated chest pain syndromes.

BACKGROUND: Animal and human experimental studies have yielded conflicted data regarding the effects of cocaine on cardiovascular function. We studied the cardiac and hemodynamic profiles in emergency department chest pain patients following recent cocaine use. METHODS: After obtaining informed consent, emergency department patients who presented with a chief complaint of chest pain and cocaine use within 24 hours of arrival were prospectively enrolled. All patients underwent a structured 40-item history and physical examination and were placed on the IQ Noninvasive Hemodynamic Surveillance System (Renaissance Technology, Inc., Newton, PA), a validated transthoracic cardiac output monitor. The principal measurements obtained included cardiac output, cardiac index, and stroke volume. Data were analyzed with standard descriptive techniques. RESULTS: Twenty-seven patients were enrolled (median age, 37 years [range, 23-54]; 74% male). Patients used a mean of $200 worth of cocaine, usually crack (67%). Patients had a history of tobacco use (82%), prior myocardial infarction (33%), and prior cocaine-associated chest pain (67%). The median (interquartile range; IQR) for the hemodynamic parameters were: mean arterial blood pressure 92 mm Hg (IQR 85-100); heart rate 83/min (IQR 72-98); cardiac output 6.9 L/min (IQR 5.1-7.2); cardiac index 3.2 L/min/m2 (IQR 2.4-4.0); stroke volume 78 mL/beat (IQR 64-93). CONCLUSION: Most emergency department patients with cocaine-associated chest pain have normal cardiac profiles at the time of presentation. The negative inotropic effects of high doses of cocaine observed in animal models do not appear to be present in patients who develop chest pain after using recreational doses of cocaine.

A sighting of orbital pseudotumor.

A 39-year-old woman developed bilateral proptosis, photophobia, and pain with extraocular movements over the course of 5 days. Her findings initially were ocular pain and photophobia which progressed to periorbital edema and nasal discharge ultimately resulting in proptosis with vertical globe displacement and decreased visual acuity. She was diagnosed with corneal abrasion and sinusitis respectively during two initial emergency department visits. On her third visit to the emergency department within 4 days, she developed acute visual deficits. The patient was subsequently diagnosed with orbital pseudotumor after computed tomography scan revealed inflammation of orbital structures bilaterally.

Herbal and alternative medicine.

An extensive range of herbal and dietary supplements is now available, and use of these products by ED patients is fairly common. Emergency physicians should be familiar with some of the products used more frequently for common complaints. Emergency personnel also should be vigilant for toxic syndromes resulting from ingestion of certain of these products and be wary of possible toxicity from any of these supplements owing to their minimal quality control and absence of FDA regulation.

A descriptive study of an epidemic of poisoning caused by heroin adulterated with scopolamine.

OBJECTIVE: Adulterants, contaminants, and diluents are all examples of additives to street drugs. Some of these additives may be pharmacologically active; however, it is unusual for them to cause toxic side effects. In the spring of 1995, a new form of heroin appeared in New York City, spreading to other East Coast cities, that was adulterated with scopolamine. It caused severe anticholinergic toxicity in heroin users with patients often presenting to emergency departments in great numbers. This is a report of the demographics and clinical characteristics of the epidemic. METHODS: A combination of prospective and retrospective data collection from the New York City, New Jersey, Delaware Valley, and Maryland Poison Centers. The primary measurements were age, sex, route of drug use, vital signs, signs and symptoms, disposition, and treatment. RESULTS: Of the 370 cases reported to the participating poison centers, 129 were excluded from the final analysis because of insufficient data. Of the patients who used this product, 55% presented with signs and symptoms of heroin toxicity but then became severely agitated with anticholinergic symptoms when naloxone was used to reverse respiratory depression. Nasal insufflation was the route of administration in 34% of the cases. Seizures were rare (3%). Ninety percent required admission, and half were admitted to a critical care unit. CONCLUSIONS: Adulteration of street drugs can lead to toxic epidemics. Poison centers are essential for identification of these trends and are the primary source of information on diagnosis and treatment.

Predictive properties of a qualitative urine acetaminophen screen in patients with self-poisoning.

OBJECTIVE: Screening for acetaminophen toxicity is recommended in almost all cases of self poisoning. We compared a qualitative urine acetaminophen screen to the quantitative serum acetaminophen to test the hypothesis that a negative urine acetaminophen screen would be predictive of a negative serum acetaminophen level. METHODS: All adults with intentional ingestions evaluated in our Emergency Department during 1995 were retrospectively identified based on Emergency Department International Classification of Disease--9th edition codes. Laboratory data from each patient including serum and urine toxicologic assays were examined. Predictive properties of urine acetaminophen screens for serum acetaminophen were evaluated. RESULTS: A total of 88 patients were identified who had both a serum acetaminophen and a urine acetaminophen performed. The sensitivity of the urine acetaminophen screen was 100% (95% CI 72-100%) and the specificity was 87% (95% CI 80-95%). All patients with negative urine acetaminophen screens had negative serum acetaminophen levels (negative predictive value 100%; 95% CI 96-100%). Accuracy of the urine acetaminophen screen was 89%. CONCLUSION: A negative urine acetaminophen screen was highly predictive of negative serum acetaminophen levels. It is possible that negative urine acetaminophen screens may obviate the need for 4-hour quantitative serum levels. Further validation in a prospective study is needed.

Flow cytometric DNA analysis of early stage adenocarcinoma of the cervix.

OBJECTIVE: The aim of this study was to determine the utility of DNA flow cytometry as a prognostic indicator for risk of recurrence and overall survival in patients with early stage adenocarcinomas of the uterine cervix. METHODS: DNA flow cytometry was performed to determine ploidy, DNA index, and proliferative index in 66 women with stage IB and IIA pure mucinous adenocarcinomas of the cervix treated by primary surgical therapy with radical hysterectomy and pelvic lymphadenectomy. Fifty-seven of 66 (86.3%) tissue samples were analyzable. Three sections were obtained from paraffin-embedded tissue blocks containing primary tumor. Flow cytometric results, along with other known prognostic variables for risk for recurrent disease and survival, were analyzed using the Cox regression proportional hazards model and survival curves generated by the Kaplan-Meier method. RESULTS: Of 57 interpretable samples, DNA ploidy patterns were 18 (27%) diploid, 8 (12%) tetraploid, and 31 (47%) aneuploid. Thirteen of 66 patients (20%) experienced recurrence with a median time to recurrence of 1.6 years. No significant correlation was noted between DNA ploidy and risk of recurrence (P = 0.429). Multivariate analysis confirmed that positive metastatic lymph nodes were associated with risk of recurrence (P < 0.001). In node-negative patients, a high proliferative index (S% + G(2)M% > 20%), measured as a continuous variable, was the only significant factor for tumor recurrence (P = 0.002). CONCLUSION: DNA ploidy does not predict a patient's risk for tumor recurrence; however, a high proliferative index value warrants further investigation as a potential prognostic indicator for risk of recurrent disease in patients with adenocarcinoma of the uterine cervix.

Flow-cytometric DNA analysis of early stage adenocarcinoma of the cervix.

OBJECTIVE: The purpose of this study was to determine the utility of DNA flow cytometry as a prognostic indicator for risk of recurrence and overall survival in patients with early stage adenocarcinomas of the uterine cervix. METHODS: DNA flow cytometry was performed to determine ploidy, DNA index, and proliferative index in 66 women with stages IB and IIA pure mucinous adenocarcinomas of the cervix treated by primary surgical therapy with radical hysterectomy and pelvic lymphadenectomy. Fifty-seven of 66 (86.3%) tissue samples were analyzable. Three sections were obtained from paraffin-embedded tissue blocks containing primary tumor. Flow-cytometric results, along with other known prognostic variables for risk for recurrent disease and survival, were analyzed using Cox regression proportional hazards model, and survival curves were generated by the Kaplan-Meier method. RESULTS: Of 57 interpretable samples, DNA ploidy patterns were 18 (27%) diploid, 8 (12%) tetraploid, and 31 (47%) aneuploid. Thirteen of 66 patients (20%) experienced recurrence with a median time to recurrence of 1.6 years. No significant correlation was noted between DNA ploidy and risk of recurrence (P = 0.429). Multivariate analysis confirmed that positive metastatic lymph nodes were associated with risk of recurrence (P < 0.001). In node-negative patients, a high proliferative index (S% + G(2)M% > 20%), measured as a continuous variable, was the only significant factor for tumor recurrence (P = 0.002). CONCLUSION: DNA ploidy does not predict a patient's risk for tumor recurrence; however, a high proliferative index value warrants further investigation as a potential prognostic indicator for risk of recurrent disease in patients with adenocarcinoma of the uterine cervix.

Laboratory confirmation of scopolamine co-intoxication in patients using tainted heroin.

BACKGROUND: First described in 1995, at least 325 patients with a history of heroin use have since required emergency medical evaluation in several eastern US cities, because of an anticholinergic toxidrome following use of heroin. This co-intoxication has been alleged to result from an atropine-like compound. We report the clinical findings and laboratory analysis of one of several individuals who presented to our Emergency Department during this epidemic. CASE REPORT: A 23-year-old male was one of 3 patients brought to the Emergency Department due to agitated behavior after insufflating heroin. Following physical and chemical restraint, vital signs were pulse 134 bpm, BP 160/90 mm Hg, RR 24/min, and T 37.3 degrees C. Physical examination was remarkable for dilated pupils 8-9 mm without nystagmus, along with dry mouth, decreased bowel sounds, and flushed dry skin. A bladder catheter was placed and 500 mL of urine was obtained. Electrocardiogram revealed sinus tachycardia only. Additional sedation was required for 12 hours until normal mental status returned. A small sample of the "heroin" used was obtained and analyzed. Scopolamine was confirmed by gas chromatography-mass spectrometry. Further evidence of scopolamine intoxication was supported by identifying scopolamine in the urine of this patient. CONCLUSION: Gas chromatography-mass spectrometry revealed scopolamine to be the cause of anticholinergic findings in a patient following use of tainted heroin. It is unclear whether scopolamine is an adulterant or contaminant in this heroin. Patients with anticholinergic findings following use of heroin may be co-intoxicated with scopolamine.

Emulating the visual receptive-field properties of MST neurons with a template model of heading estimation.

We have proposed previously a computational neural-network model by which the complex patterns of retinal image motion generated during locomotion (optic flow) can be processed by specialized detectors acting as templates for specific instances of self-motion. The detectors in this template model respond to global optic flow by sampling image motion over a large portion of the visual field through networks of local motion sensors with properties similar to those of neurons found in the middle temporal (MT) area of primate extrastriate visual cortex. These detectors, arranged within cortical-like maps, were designed to extract self-translation (heading) and self-rotation, as well as the scene layout (relative distances) ahead of a moving observer. We then postulated that heading from optic flow is directly encoded by individual neurons acting as heading detectors within the medial superior temporal (MST) area. Others have questioned whether individual MST neurons can perform this function because some of their receptive-field properties seem inconsistent with this role. To resolve this issue, we systematically compared MST responses with those of detectors from two different configurations of the model under matched stimulus conditions. We found that the characteristic physiological properties of MST neurons can be explained by the template model. We conclude that MST neurons are well suited to support self-motion estimation via a direct encoding of heading and that the template model provides an explicit set of testable hypotheses that can guide future exploration of MST and adjacent areas within the superior temporal sulcus.