James Dougherty

Current status of plasmapheresis in toxicology

Although the elimination of specific toxins by the removal of all plasma constituents is a crude approach, further refinements of the technique should permit safer and more selective detoxification in the future. Currently the mainstay of treatment of intoxicated patients remains careful, aggressive, supportive care. Plasmapheresis should be considered as yet an unproven, hazardous form of therapy for the treatment of intoxication. Its main role should be confined to a research setting in which investigators attempt to develop more advanced and potentially useful apheresis techniques. Membrane plasmapheresis with subsequent on-line treatment of the plasma by sorbent may remove specific plasma solutes. The plasma may be perfused back to the patient without the need to use replacement fluids, thus avoiding many of the side effects of conventional exchange. Bile acids have been removed by circulating plasma over charcoal-coated glass beads, and several toxic substances were shown to be absorbed by perfusion over amberlite resin columns. Another productive area for future research includes the use of plasma exchange therapy for the treatment of acute endogenous intoxications. Recent examples include the treatment of severe preeclampsia, extensive rhabdomyolysis, and life-threatening bleeding in a hemophiliac with inhibitors to clotting factors. Although plasmapheresis in the management of intoxications is still an experimental technique, it may open the door to the treatment of previously intractable syndromes, both medical and toxicologic.

Radial artery cannulation guided by Doppler ultrasound

A technique to enhance difficult percutaneous radial artery cannulations using Doppler ultrasound is described. A series of 12 patients (nine hypotensive and three normotensive patients with poorly palpable or absent radial pulses) was assembled and the radial arteries were cannulated using standard intravenous catheters and a hand-held Doppler ultrasound device. Localization and cannulation of the arteries was facilitated by noting the characteristic sounds using the Doppler. Eleven of the 12 patients had successful cannulation of the radial artery. In one case the artery was localized but the catheter could not be advanced. No complications were encountered. It was concluded that the use of a common Doppler ultrasound on selected patients with poor peripheral pulses may facilitate percutaneous radial artery cannulations and minimize the number of catheter punctures before successful placement.

Tagamet®-induced acute dystonia

A 20-year-old woman presented with an apparent acute dystonic reaction after only five doses of cimetidine (Tagamet). The patient was on no other medications with the exception of oral contraceptives. Emergency administration of IV diphenhydramine HCL brought rapid reversal of this acute dystonic reaction without any neurological sequelae. To our knowledge, this is the first reported case of an acute dystonic reaction associated with cimetidine.

Transcutaneous Pacing in a Hypothermic-Dog Model

STUDY OBJECTIVE To evaluate the hemodynamic response to transcutaneous pacing (TCP) during rewarming from hypothermia. METHODS We conducted a prospective, controlled laboratory investigation using 20 mongrel dogs. The animals were anesthetized, intubated, and mechanically ventilated. Arterial pressure, core temperature, and cardiac rhythm were continuously monitored. All dogs were cooled to a core temperature of 27 degrees C; experimental animals were then subjected to TCP with active rewarming, and control animals underwent sham transcutaneous pacing and rewarmed in the same manner. Serial hemodynamic measurements, time to rewarming, and cardiac isoenzyme concentrations were analyzed. RESULTS Rewarming was accomplished significantly faster in the paced group (171.5 +/- 31.5 minutes) than in the control group (254 +/- 55.9 minutes, P < .05). After rewarming, the mean cardiac index in the paced dogs returned to 84% of baseline, compared with 63% of baseline in the nonpaced group (P < .05). None of the paced animals demonstrated significant hemodynamic deterioration, potentially lethal arrhythmias, or other evidence of myocardial injury. CONCLUSION TCP is safe, effective and easily implemented in dogs. In this small series of dogs, TCP restored and maintained hemodynamic stability and allowed the hypothermic animals to rewarm in half the time required by their nonpaced counterparts.

Cerebrospinal fluid cultures and analysis

Prompt and accurate diagnosis of acute central nervous system infections is of vital importance to the emergency physician. With the advent of modern antimicrobial therapy, the nearly uniformly fatal outcome of untreated bacterial meningitis can be reduced substantially. Proper test selection is crucial in arriving at a correct and timely diagnosis. A variety of tests are currently available for evaluation of the patient with an acute central nervous system infection. We review the current state of the art in central nervous system testing. Cost considerations and an algorithm for efficient selection of appropriate tests are presented.

Core temperature monitoring of firefighters during hazardous materials training sessions.

OBJECTIVE To determine core temperature (Tc) elevations in hazardous materials (HazMat) technicians wearing level-A fully encapsulated, chemically resistive suits (FECRSs) during training scenarios. DESIGN Cross-sectional, observational feasibility study with Institutional Review Board approval. SETTING HazMat training scenarios held during the summer of 1994. Weather conditions included both rainy and sunny days, with a mean ambient temperature of 75.8 degrees F (24.3 degrees C) (range 69-83 degrees F [20.6-28.3 degrees C). PARTICIPANTS Nine male firefighters participating in training scenarios in the Midwestern United States. INTERVENTIONS Each volunteer swallowed a capsule containing a Tc sensor developed by the National Aeronautics and Space Administration. The capsule continuously monitored Tc and stored data in an ambulatory recorder worn under the level-A FECRS during training. RESULTS Mean age of the volunteers was 34 years, mean weight was 92.6 kg, and average baseline Tc was 36.7 degrees C (97.1 degrees F) (range 35.3-38.2 degrees C [95.5-100 degrees F]). Time in the FECRS averaged 25.4 minutes (range 14-35 minutes). All subjects demonstrated increased Tc while in the suit; the mean Tc increase was 0.8 degree C (1.4 degrees F) (range 0.2-1.3 degrees C [0.4-2.3 degrees F]). The Tc continued to increase during wet decontamination procedures and after suit removal. Mean heat storage values (delta Tcx LBMx 3.47 kJ) were calculated, and found to be moderately elevated to 3.6 kJ/kg (range 2.1-4.6 kJ/kg). CONCLUSION These observations support the validity and significance of implementing prophylactic measures for firefighters using protective clothing. Simple protective measures include enforced time limitations, hydration, and efforts to minimize heat buildup by avoiding both direct sunlight and unnecessary time encapsulated in the suit.

Use of rib belts in acute rib fractures

The current treatment for uncomplicated rib fractures is the exclusion of associated injuries followed by symptomatic treatment with analgesics. Encouragement of deep breathing is also recommended to avoid secondary or delayed pulmonary complications. The use of circumferential rib belts in treating patients with acute rib fractures has been discouraged because of possible complications from restricted ventilation. A review of the literature revealed no previous clinical studies to support this view. We designed and conducted a controlled, prospective, randomized pilot study to determine if there was any increased morbidity associated with the use of rib belts in the treatment of patients with acute rib fractures. Twenty-five adult patients with radiographically proven acute rib fractures were randomized into two groups. The first group was treated with analgesics and a standard circumferential rib belt (Zimmer Universal Rib Belt). The second group was treated with oral analgesics alone. Patients were contacted by telephone three days after the initial injury and then reexamined 14 days postinjury. Rates of pain resolution, compliance, and delayed complications were determined. Rib belts were not found to significantly reduce the severity of pain. Four complications (one case of bloody pleural effusion requiring hospitalization, two cases of asymptomatic discoid atelectasis, and one case of allergic contact dermatitis) were identified, all occurring in the group of patients receiving rib belts. This pilot study indicates that while rib belts are widely accepted by patients for control of pain, they appear to be associated with an increased incidence of complications. Clinical studies with larger sample sizes will be needed to confirm these findings.