Basaloid squamous cell carcinoma of the supraglottic larynx.

Basaloid squamous cell carcinoma (BSC) is regarded as a variant of squamous cell carcinoma, but displays distinct morphological and biological features as well as a different clinical course. The tumor is frequently seen in the head and neck and is preferentially located in the larynx, especially in supraglottic sites. Ten patients with BSC of the supraglottic larynx were treated from 1991 to 1995 at the Medical Faculty of the University of Istanbul. Results of treatment were compared retrospectively with a control group consisting of 44 patients with well-differentiated squamous cell carcinomas. Ages, localizations, stages and treatment procedures were similar. In both groups mean survival, nodal involvement and distant metastases were comparable although the local (laryngeal) recurrence rate in patients with early supraglottic (T2) disease in the BSC group after conservative partial surgery was distinct compared to the control group (P < 0.05). These results indicate that conservative surgery should be assessed with caution in patients with BSC, and postoperative irradiation be taken into consideration.

Acute pericardial distension in pigs: effect of fluid conductance on body surface electrocardiogram QRS size.

OBJECTIVES: Pericardial effusion has long been associated with low voltage of the surface electrocardiogram and its clinical utility is well known. The cause of this reduced QRS voltage has usually been attributed to short circuiting of the impulses by the pericardial fluid, but its precise mechanism has not been clearly elucidated. Therefore, we investigated this phenomenon by instilling various fluids with different resistances in increasing volumes into the pericardial space to finally produce acute cardiac tamponade. METHODS: Acute cardiac tamponade was produced 65 times in 25 closed chest pigs with a mean weight of 57(SEM 1.2) kg. A sufficient quantity (mean = 200 ml) of plasma, saline, blood, and blood with varying packed cell volume was introduced into the pericardial space in 60 ml increments to decrease systemic and pulmonary pressures to 50% of control to produce cardiac tamponade. At that point intrapericardial pressure had increased to 15-20 mm Hg. Resistivity values for the instilled fluids are 150 omega-cm for blood, 60 omega-cm for plasma, and 50 omega-cm for saline. RESULTS: Mean limb and precordial lead QRS voltage fell significantly, with no significant differences among these fluids. Electrocardiograph recordings from a unipolar electrode catheter in the right ventricle showed an increase in R wave voltage, but body surface recordings of stimuli introduced into the right atrium via a bipolar electrode catheter showed no amplitude change. CONCLUSIONS: In considering possibilities such as internal shunting of cardiac currents by intrapericardial fluid, distance of the heart from body surface electrodes, and change in cardiac position, the results are best explained by a reduction of cardiac volume and size during cardiac tamponade. This conclusion confirms Brody's hypothesis.

Plasma cocaine and tetracaine levels following application of topical anesthesia in a swine laceration model.

Standard TAC (0.5% tetracaine, 0.05% epinephrine, and 11.8% cocaine) solution is finding increased use as a topical anesthetic for lacerations. The extent of systemic absorption of TAC components and their resultant physiologic effects are unclear. Absorption of cocaine or tetracaine may result in serious toxicity. The investigators hypothesized that there are no measurable plasma cocaine or tetracaine levels after application of TAC in a swine laceration model. After an overnight fast 10 domestic swine underwent tracheostomy, mechanical ventilation, femoral venous, and arterial cannulation. Maintenance anesthesia with intermittent thiopental and pancuronium was provided to maintain stage III anesthesia. Heart rate (HR), arterial pressure (BP), plasma cocaine, and tetracaine levels were measured at intervals for 180 minutes. Five milliliters of TAC was applied for 15 minutes to a standardized facial laceration in experimental swine (n = 5). Randomly labeled plasma samples were placed in vials containing 2% sodium fluoride and 1% potassium oxalate, immediately refrigerated, and analyzed for cocaine and tetracaine using gas chromatography and mass spectroscopy. Significant changes in HR and mean BP, compared with baseline values, were analyzed using Dunnett's multiple range test. Plasma cocaine levels were measurable in all experimental swine after 10 minutes, while no tetracaine was detectable. No significant differences in HR or BP changes were observed between experimental and control subjects. Application of standard TAC solution results in measurable plasma cocaine levels, but not tetracaine. Further studies into anesthetic formulation, as well as timing and technique of application, are required before consensus on optimal emergency departmental use of topical anesthesia can be achieved.