Lary A. Robinson

Intrapleural fibrinolytic treatment of multiloculated thoracic empyemas

Acute multiloculated thoracic empyemas incompletely drained by tube thoracostomy alone usually require operation. To avoid a thoracotomy yet treat this difficult problem, intrapleural fibrinolytic agents were employed. Between April 1, 1990, and April 1, 1993, 13 consecutive patients presenting with a fibrinopurulent empyema were demonstrated to have incomplete drainage. To facilitate drainage, streptokinase, 250,000 units in 100 mL 0.9% saline solution (3 patients), or urokinase, 100,000 units in 100 mL 0.9% saline solution (10 patients), was instilled daily into the chest tube, and the tube was clamped for 6 to 12 hours followed by suction. This routine was continued daily for a mean of 6.8 +/- 3.7 days (range, 1 to 14 days) until resolution of the pleural fluid collection was demonstrated by computed chest tomography and clinical indications. This regimen was completely successful in 10 of 13 patients (77%), who had resolution of the empyema, eventual withdrawal of chest tubes, and no recurrence. Two patients, both pediatric liver transplant patients, had an initial good response but eventually required decortication. One patient with a good radiographic response became increasingly febrile during streptokinase therapy and underwent a thoracotomy, but no significant undrained fluid was found. This patients continued fever was believed to be a streptokinase reaction. Urokinase was used subsequently. No treatment-related mortalities or complications occurred. Intrapleural fibrinolytic agents, especially urokinase, are safe, cost-effective means of facilitating complete chest tube drainage, thereby avoiding the morbidity of a major thoracotomy for 77% of a group of multiloculated empyema patients who traditionally would have required open surgical therapy.

Intrapleural doxycycline control of malignant pleural effusions

The intrapleural instillation of agents for pleural sclerosis has proved effective in preventing the reaccumulation of symptomatic malignant pleural effusions. Because manufacture of the most popular agent, tetracycline, was recently discontinued, a preliminary study was undertaken to evaluate an alternative agent, doxycycline, for treating symptomatic malignant pleural effusions. From November 1991 to September 1992, 21 patients with symptomatic malignant pleural effusions have undergone overnight chest tube drainage followed by intrapleural instillation of 10 mL 1% lidocaine and then doxycycline, 500 mg in 30 mL 0.9% saline solution. The chest tube was clamped 2 hours with patient repositioning every 15 minutes. Tubes were removed when drainage was less than 50 mL/8 h. Of surviving patients, a complete objective response at 1 month was obtained in 88% (15/17), who were free of a symptomatic or radiographic recurrence of the effusion. Complications included mild pain in 23% (5/21), moderate pain requiring analgesics in 19% (4/21), and mild fever in 5% (1/21). There were no treatment-related deaths. The mean time for chest tube removal was 1.7 +/- 0.7 days after the last treatment. Based on this preliminary study, we conclude that doxycycline is a highly effective agent for the palliative treatment of symptomatic malignant pleural effusions. Its safety profile and efficacy compare favorably with those of tetracycline and other agents used for pleural sclerosis.

Defibrillator twiddler's syndrome

Long-term complications of internal cardioverter defibrillators have generally involved inappropriate shocks or hardware malfunctions. The present case documents a new problem of internal cardioverter defibrillator lead disruption resulting from patient-induced rotation of the generator in its pocket, similar to the previously reported pacemaker twiddlers syndrome. However, unlike the usual early symptoms of pacemaker nonfunction, the first symptomatic manifestation of the defibrillator twiddlers syndrome may be an inappropriate internal cardioverter defibrillator discharge or more importantly, unrescued sudden death. Careful attention to patient complaints about the internal cardioverter defibrillator generator and being alert to subtle lead changes on chest radiographs may allow the clinician to recognize this syndrome before a major, possibly fatal event.

Valve replacement in the right side of the heart in children: long-term follow-up

Twenty-five patients (16 male, 9 female) underwent right-sided valve replacement (10 pulmonary valve replacement, 14 tricuspid valve replacement, 3 tricuspid plus pulmonary valve replacement, and 2 replacements of a single atrioventricular valve) at the University of Nebraska Medical Center from June 1977 to December 1986. Twenty-one patients (84%) are long-term survivors with 2,035 months follow-up (range, 41 to 143 months; mean, 96.9 months). Twenty-three Carpentier-Edwards bioprosthetic valves, one Ionescu-Shiley bioprosthetic valve, and nine St. Jude Medical valves were inserted. Follow-up of 17 patients with a Carpentier-Edwards valve ranged from 5 years 9 months to 11 years 9 months (mean, 8 years 11 months). To date there has been one reoperation after 3 years 4 months in this group. One patient who received an Ionescu-Shiley bioprosthesis required re-replacement at 20 months after operation. Three of 4 patients who received St. Jude mechanical valves and are long-term survivors have required replacement after 36 to 56 months. We conclude that the Carpentier-Edwards bioprosthetic valve is a viable option in the right side of the heart in the young age group when annular size is adequate to accommodate an appropriate bioprosthesis.

Benign mediastinal teratoma masquerading as a large multiloculated effusion

Benign mediastinal teratomas are uncommon germ cell tumors often discovered while still asymptomatic. Almost all arise in the anterosuperior mediastinal compartment, and most symptoms, when present, result from compression of adjacent structures. We report a case of a large teratoma arising from the anterior mediastinum that presented a confusing clinical picture of a multiloculated pleural effusion. It was successfully treated by surgical excision, with no long-term recurrence.

Options in managing the patient with high defibrillation thresholds

The desired defibrillation threshold (DFT) obtained during intraoperative testing of an implantable cardioverter defibrillator (ICD) should be 10 J lower than the maximal energy delivered by the ICD generator. Of the 206 patients undergoing ICD implantation since December 1986, 8 (3.9%) have had initial DFTs with less than the 10-J safety margin using the standard large patch-large patch configuration. Patches were implanted by left thoracotomy in 6 and sternotomy in 1, and 1 had implantation of a transvenous defibrillation lead and subcutaneous patch. Of note, 6 (75%) of the 8 patients with high DFTs had prior open heart operations, half were on a regimen of long-term amiodarone therapy, and the mean left ventricular mass index was quite large but not significantly greater than that of patients with low DFTs. Multiple techniques was tried to improve the DFTs in this group. Satisfactory DFTs were eventually obtained in 7 (88%); the threshold was lowered from a mean of 41.4 +/- 3.8 J to 26.9 +/- 8.8 J (p = 0.002). The most effective techniques were addition of a superior vena cava lead attached by a Y connector to one of the large patch leads in some patients and conversion to a biphasic-waveform generator in 2 others. Adding a third epicardial lead did not lower the DFTs. There were no major postoperative complications or deaths attributable to these supplemental procedures. Using these techniques, satisfactory DFTs were obtained in almost all patients with an ICD.(ABSTRACT TRUNCATED AT 250 WORDS)

Proenkephalin- A derived peptides do not modulate cardiovascular effects of epinephrine on the isolated rat atrial preparations

The catecholamines and the opioid peptides are found to be co-localized in the adrenomedullary chromaffin cells. They are co-secreted from the chromaffin granules in response to various stimuli. The stress-induced released of epinephrine is known to exert its effect on the cardiovascular system resulting in the changes in heart rate and blood pressure. However, the role of the co-released proenkephalin-A derived peptides has not been extensively characterized. Previous work from several investigators suggested that the peptides modulate cardiac functions of the catecholamines. There is considerable conflicting results among these reports. Results from the isolated rat atrial preparation indicated that enkephalins attenuated the increase in atrial rate induced by norepinephrine through restriction of the calcium fluxes. Nonetheless, others reported insensitivity of the enkephalins in similar or different test systems. We further re-examined these discrepancies using the isolated rat atrial preparation to investigate the opioid peptide modulatory effect on the cardiovascular changes induced by exogenous epinephrine. Alterations in rate and force of contraction resulting from epinephrine and the peptides were both studied in parallel. The opioid peptides used in this study were [Met5]-enkephalin (ME), [Leu5]-enkephalin (LE), FMRFamide, [Met5]-enkephalyl-Arg6-Phe7 (MEAP), peptide E, and the non-selective opioid agonist, etorphine. We report here that none of the opioid peptides were effective in alleviating or attenuating the increase in heart rate and developed tension caused by epinephrine. The peptides did not affect the basal beating rate nor the force of contraction. Thus, the present results clearly demonstrate the insensitivity of the enkephalins in modulating the cardiac effects of epinephrine. They further indirectly support the prejunctional synaptic nerve endings as the potential peripheral site of action of the peptides.