Biomedical subjects

C Pruitt

Publications and source records attributed to C Pruitt.

7 recordsLinked to original sources

PubMed1997

Civilian colon trauma: factors that predict success by primary repair.

BACKGROUND: Primary repair has become the most common method of treatment for civilian injuries of the colon. However, colostomy may still be required in selected patients. AIMS: This study was undertaken to identify factors for the performance of colostomy in patients with colon injuries. METHODS: During a 60-month period, all penetrating injuries to the colon treated at Saint Louis University Hospital were evaluated. All patients underwent an operation within six hours of injury. Rectal injuries were excluded. RESULTS: One hundred thirty consecutive patients with injuries to the colon were identified. Primary repair was performed in 81 patients (62 percent). Fecal diversion was used in 49 patients (38 percent). No deaths occurred related to colon injury. Complications related to colon injury included wound infections in 22 patients (17 percent) and intra-abdominal complications in 16 patients (abscess, 14; fecal fistula, 1). Wound complications were most closely related to whether the skin was closed primarily or left open (22 vs. 8 percent). Intra-abdominal complications occurred in 7 percent of patients in whom the colon injury was closed primarily and in 20 percent of patients in whom a stoma was created (P > 0.05). Patients chosen for colostomy had significantly greater blood loss, more associated injuries, and higher scores on the Abdominal Trauma Index (ATI) and Colon Injury Scale (CIS) and were more likely to have gross contamination (P < 0.05). Stepwise regression analysis of 13 factors revealed that only gross contamination and ATI predicted the occurrence of intra-abdominal complications and that CIS most closely predicted either wound or intra-abdominal complications. Stratification of patients based on an ATI of > or =30 and a CIS of > or =4 revealed no difference in outcome between primary repair and colostomy in either the low-risk or high-risk groups. However, severity of injury was greater in patients treated with colostomy. CONCLUSIONS: Primary repair can be accomplished with low morbidity in the majority of civilians with penetrating injuries to the colon. Colostomy may be required in high-risk patients as defined by an ATI of > or =30 in association with a CIS of > or =4.

Adolescent↗

PubMed1996

Management of selected rectal injuries by primary repair.

BACKGROUND: Diversion of the fecal stream with or without primary repair has been the mainstay of therapy for rectal injuries. Because primary repair has replaced colostomy as the treatment of choice for most colon injuries, we reviewed our experience with primary repair of rectal injuries in order to determine if primary repair without diversion is a feasible option in selected patients. MATERIALS AND METHODS: All traumatic rectal injuries over the past 48 months were reviewed for mechanism of injury, diagnosis, treatment, and outcome. RESULTS: Thirty consecutive patients with extraperitoneal rectal injuries were identified. Six of the 30 patients underwent primary repair without diversion. Five were repaired transanally, and 1 was repaired at celiotomy. There was no morbidity related to the rectal repair in patients who underwent primary repair without diversion, and there were no deaths. CONCLUSIONS: Based on a small number of patients, these data suggest that primary repair of rectal injuries in selected patients may be feasible. Further prospective investigation is needed to determine which patients may be successfully treated in this fashion.

Adolescent↗

PubMed1994

The effects of beta-adrenergic stimulation on the frequency-dependent electrophysiologic actions of amiodarone and sematilide in humans.

BACKGROUND: The autonomic nervous system appears to play an important role in the development of clinical ventricular arrhythmias, and beta-adrenergic sympathetic stimulation may be important in modulating the electrophysiologic effects of class III antiarrhythmic agents. This study prospectively determined the effects of isoproterenol on the frequency-dependent actions of sematilide (a pure class III agent that selectively blocks the delayed rectifier potassium current) and amiodarone (a class III agent with a complex pharmacologic profile) on ventricular repolarization, refractoriness, and conduction. METHODS AND RESULTS: The frequency-dependent electrophysiologic effects of sematilide (n = 11) and amiodarone (n = 22) were determined at (1) drug-free baseline, (2) during steady-state (> 48 hours) dosing with sematilide (455 +/- 5 mg/d [mean +/- SEM]) or after 10.5 days of amiodarone loading (1618 +/- 32 mg/d), and (3) during isoproterenol administration (35 ng/kg per minute) to patients receiving sematilide or amiodarone. Electrophysiologic determinations were made at paced cycle lengths of 300 to 500 ms. The two groups were similar in all clinical characteristics. The ventricular action potential duration at 90% repolarization (APD90) was significantly prolonged by sematilide (mean increase, 7 +/- 1%, P < .01 by ANOVA) and amiodarone (mean increase, 12 +/- 1%, P < .001). However, while sematilide-induced APD90 prolongation was fully reversed to baseline values during isoproterenol infusion, the APD90 in patients receiving amiodarone remained significantly prolonged by a mean of 6 +/- 1% compared with baseline (P = .005). The reduction in the APD90 was frequency dependent for both agents, with a greater reduction at longer than shorter paced cycle lengths (P < .02). During isoproterenol infusion the right ventricular effective refractory period (RVERP) in patients receiving sematilide was significantly reduced to mean values of 8 +/- 2% below baseline (P < .05), whereas the RVERP in patients receiving amiodarone remained significantly prolonged by a mean of 7 +/- 1% above baseline values (P = .01). Sematilide and sematilide/isoproterenol had no effect on ventricular conduction. Amiodarone increased the QRS duration by 14 +/- 4% (paced cycle length, 500 ms) to 32 +/- 5% (paced cycle length, 300 ms) compared with baseline values. Isoproterenol attenuated amiodarone-induced QRS prolongation by a mean of 5 +/- 1% (P = .005), without frequency-dependent effects, consistent with isoproterenol-induced increases in the sodium current. During isoproterenol infusion there was a trend for the sustained VT cycle length to be reduced below baseline in patients receiving sematilide (275 +/- 16 versus 298 +/- 55 ms, P = .06), whereas it remained significantly prolonged compared with baseline in patients receiving amiodarone (327 +/- 17 versus 257 +/- 12 ms, P < .001). CONCLUSIONS: Isoproterenol fully reversed the effects of selective potassium channel block with sematilide on the APD90 and further reduced the RVERP to values significantly below baseline; it partially attenuated but did not fully reverse amiodarone-induced prolongation of the APD90 and RVERP, which remained significantly prolonged beyond baseline values. Isoproterenol exerted frequency-dependent effects in both patient groups on the APD90; it modestly attenuated amiodarone-induced conduction slowing without frequency-dependent actions; and the sustained VT cycle length remained significantly prolonged during isoproterenol administration to patients receiving amiodarone but not in those receiving sematilide. These findings may have important clinical implications regarding protection from arrhythmia development in patients receiving pure class III agents or amiodarone.

Action Potentials↗

PubMed1993

Frequency-dependent electrophysiologic effects of amiodarone in humans.

BACKGROUND: In general, antiarrhythmic agents that prolong the action potential duration (APD) have attenuated effects on repolarization at short cycle lengths (reverse frequency dependence), and this may limit their efficacy for controlling ventricular arrhythmias. The frequency-dependent effects of amiodarone on repolarization may differ from those of other antiarrhythmic agents and have not been determined in humans. METHODS AND RESULTS: The frequency-dependent effects of amiodarone on repolarization and conduction were determined during electrophysiologic study in 19 patients at drug-free baseline and after 11 days of amiodarone loading (1621 +/- 162 mg/d, group A) and in 15 additional patients after > or = 1 year of chronic amiodarone therapy (380 +/- 56 mg/d, group B). The two groups were similar in all clinical characteristics. The ventricular APD at 90% repolarization (APD90), right ventricular effective refractory period (VERP), and QRS duration were determined at paced cycle lengths of 300 to 600 milliseconds. In group A, amiodarone significantly (10% to 13%, P < .001) increased the APD90 at all paced cycle lengths by approximately 30 milliseconds compared with baseline. Similarly, there were no frequency-dependent effects on the percent increase in VERP. However, there was greater amiodarone-induced prolongation of the VERP magnitude at longer paced cycle lengths than at shorter cycle lengths (P = .04), although the VERP remained significantly prolonged at the shortest paced cycle length (300 milliseconds) by 33 +/- 22 milliseconds (16.9% increase from baseline, P < .001). Amiodarone significantly (P < .01) increased the QRS duration at paced cycle lengths < or = 500 milliseconds by a maximum of 28% compared with baseline measurements. The increase in ventricular conduction time was frequency dependent (P < .01), consistent with significant sodium channel blockade. The VERP/APD90 ratio (determined at twice diastolic threshold) was significantly prolonged by amiodarone (as compared with baseline) at cycle lengths > or = 400 milliseconds, indicative of both time- and voltage-dependent effects on refractoriness. The increase in induced sustained ventricular tachycardia cycle length in group A patients after amiodarone loading was significantly correlated with the increase in VERP (r = .68, P = .044) but not with increases in QRS duration or APD90. In addition, there were no significant differences in frequency-dependent effects of amiodarone between groups A and B. CONCLUSIONS: The frequency-dependent response of the electrophysiologic effects of amiodarone are similar after 11 days of loading or > or = 1 year of chronic therapy. Amiodarone does not exert frequency-dependent effects on ventricular repolarization; it prolongs refractoriness by both time- and voltage-dependent mechanisms and exerts frequency-dependent effects on ventricular conduction. The absence of amiodarone-induced reverse frequency-dependent effects on repolarization, together with its time-dependent effects on refractoriness may account in part for the high efficacy of the drug and its low propensity to cause torsade de pointes.

Amiodarone↗

PubMed1993

Antiarrhythmic effects of selective prolongation of refractoriness. Electrophysiologic actions of sematilide HCl in humans.

BACKGROUND: Recent data have suggested that antiarrhythmic agents that act largely by delaying conduction may not be as effective in controlling ventricular arrhythmias as those that prolong repolarization. Recently, numerous "pure" class III agents have been developed. METHODS AND RESULTS: The antiarrhythmic and electrophysiologic profiles of sematilide, a "pure" class III agent, were determined in 27 patients with clinical ventricular arrhythmias and inducible sustained ventricular tachycardia during electrophysiologic study. After treatment with oral sematilide (mean dose, 133 +/- 29 mg every 8 hours), the patients underwent repeat 24-hour ambulatory ECG monitoring and electrophysiologic study. The baseline sinus cycle length and QT, QTc, JT, and JTc intervals were significantly increased 8 to 17% by sematilide (P = .001 to .029). There were no changes in the PR or QRS intervals. Sematilide (at a paced cycle length of 600 ms) significantly increased the atrial effective refractory period (238 +/- 32 to 264 +/- 32 ms; 11 +/- 16% increase from baseline; P = .013), atrioventricular nodal effective refractory period (296 +/- 74 to 354 +/- 71 ms; 20 +/- 19%; P = .029), and right ventricular effective refractory period (252 +/- 25 to 281 +/- 30 ms; 12 +/- 8%; P < .001) but did not significantly change the PA or HV intervals, the corrected sinus node recovery time, or the Wenckebach cycle length. Determination of the frequency-dependent effects of sematilide (n = 10) on the right ventricular monophasic action potential duration (APD90) during ventricular pacing at cycle lengths of 600 to 300 ms revealed that the APD90 was significantly prolonged by sematilide during ventricular pacing at 600 to 350 ms (APD90 increase of 40 +/- 17, 27 +/- 21, 18 +/- 18, and 14 +/- 15 ms, respectively) but not at 300 ms (APD increase of 13 +/- 19 ms). Sematilide significantly prolonged the APD90 to a greater degree at longer than at shorter cycle lengths (P = .02). The ventricular effective refractory period had a similar reverse frequency-dependent relation as the APD90. Sematilide had no effect on the ventricular effective refractory period-to-APD90 ratio or on ventricular conduction. Sematilide suppressed the induction of sustained ventricular tachycardia in 41% of all patients exposed to sematilide. Prolongation of ventricular refractoriness was correlated with ventricular tachycardia suppression. The right ventricular effective refractory period (at 600 ms) increased by 38 +/- 14 ms in patients whose sustained ventricular tachycardia was suppressed by sematilide and by 19 +/- 18 ms in patients not suppressed (P = .015). One patient developed short runs of pause-dependent nonsustained ventricular tachycardia. Eight patients were placed on long-term sematilide therapy, and during a mean follow-up period of 7.0 +/- 7.5 months, two patients developed sudden cardiac death, and one additional patient had recurrent sustained ventricular tachycardia. CONCLUSIONS: The electrophysiologic profile of sematilide is consistent with selective block of outward potassium currents and associated isolated lengthening of the ventricular effective refractory period and APD; sematilide demonstrates a significant degree of reverse frequency-dependence of the ventricular APD and effective refractory period; and suppression of ventricular tachycardia inducibility by sematilide appears to be correlated with increases in the right ventricular effective refractory period.

Anti-Arrhythmia Agents↗

PubMed1987

Cardiac electrophysiologic effects of intravenous ketanserin in humans.

The hypotensive effects of ketanserin, a selective blocker of 5-hydroxytryptamine2, are well defined, but its electrophysiologic effects in humans are not. Intravenous ketanserin (0.15 mg/kg) was therefore given to 10 patients undergoing electrophysiologic evaluation, and data were obtained before and after drug administration. The mean ketanserin plasma level was 389 +/- 211 ng/ml. Ketanserin decreased systolic and diastolic blood pressure, but the change did not reach statistical significance. Ketanserin increased the QTc interval by 3% (p less than 0.01), without effect on QRS or the HV intervals. Ketanserin exerted no effect on ventricular effective refractory period (ERP) but decreased the atrial ERP by 6% (p less than 0.01); the decrease in atrioventricular (AV) nodal ERP and in the AV nodal Wenkebach cycle length did not reach statistical significance. The sinus node recovery time and intranodal conduction time were shortened significantly by ketanserin. The data indicate that ketanserin has a modest effect in prolonging ventricular repolarization without influencing the fast sodium channel. Its effect on atrial refractoriness and on sinus and AV-nodal function suggests a complex interaction with the autonomic nervous system in producing its net cardiac electrophysiologic actions.

Blood Pressure↗

PubMedDate not supplied

Transaneurysmal aortic balloon tamponade.

A method consisting of direct transaneurysmal insertion of a double lumen balloon catheter designed to gain control of the inflow into ruptured or difficult to dissect aneurysms is presented.

Aorta, Abdominal↗