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Biomedical subjects

S A Syverud

Publications and source records attributed to S A Syverud.

At least 19 recordsLinked to original sources

Consideration for primary angioplasty: impact on the door-to-drug time in AMI patients ultimately treated with thrombolytic agent.

The objective of this study was to determine if consideration for percutaneous transluminal coronary angioplasty (PTCA) delays administration of thrombolytic therapy in acute myocardial infarction (AMI) patients. Retrospective medical record review of patients ultimately diagnosed with AMI who presented to the ED with chest pain and ST segment elevation on the electrocardiogram; these patients also received acute reperfusion therapy (PTCA or thrombolytic agent). AMI was diagnosed by abnormal elevations in the creatinine phosphokinase MB fraction. The study period covered 2 years (July 1, 1994 to June 30, 1996) in a university hospital ED with an annual volume of 60,000 patient-visits. The use of reperfusion therapies, time intervals, and times of presentation were recorded. Patients were divided into two groups based on cardiac catheterization laboratory (CATH) availability: (group I, CATH currently in operation, Monday to Friday, 7 am to 7 pm and group II, CATH currently not in-operation, all other times). Fifty-two patients with AMI met entry criteria. Patients were treated with thrombolytic therapy in 25 cases; PTCA in 27 cases. Patients received thrombolytic agents within statistically equivalent time intervals regardless of the period of presentation; time to thrombolytic therapy for group I patients was 38 +/- 16 minutes compared with 36 +/- 26 minutes for group II patients (P =. 891). A trend toward significance was noted in the use of PTCA compared with thrombolytic agent; Group I patients were more often treated with PTCA (19) compared with group II patients (11, P =.067). Patients were more rapidly treated with PTCA during CATH operation; the mean time to PTCA for group I patients was 73.5 minutes compared with PTCA for group II patients with 107.8 minutes (P =.033). The consideration for PTCA did not significantly delay the administration of thrombolytic therapy at the study site institution. PTCA was initiated more rapidly in patients presenting with AMI during hours of CATH operation.

Angioplasty, Balloon, Coronary↗

Failure of a new double glove hole detection system in the Emergency Department.

The purpose of this study was to evaluate the performance of a new double glove hole detection system in the Emergency Department. First, the frequency of holes in both gloves of the double glove hole detection system was determined using a watertight test method. Second, the frequency of glove puncture was determined first by searching for the optical color change that occurs with the ingress of fluid in the double glove hole detection system. These same gloves were then removed and also checked for holes by the watertight test method. After removal from the package, no holes were detected in the two gloves of the system using the watertight test method. In 50 consecutive patients, there was no color change in the inner glove indicating glove puncture. When these same gloves were then tested with the watertight test method, 14 of the 50 double glove hole detection systems failed; all 14 outer gloves were punctured, and three of the inner gloves had holes without demonstrable injury to the skin. This double glove hole detection system is not a reliable system to detect holes in relatively dry clinical settings because the ingress of fluid by capillary action between the gloves is necessary to cause a color change in the inner glove that signals the presence of a hole.

Arthroplasty↗

Future planning.

Explore the source record for details and available documents.

Academic Medical Centers↗

Case conference: complete heart block in a young man.

A previously healthy 32-year-old man presented to the ED in complete heart block. Ischemic, infectious, and inflammatory conditions were considered in the differential diagnosis. Management options for complete heart block, the etiology of heart block in young adults, and treatment guidelines are reviewed.

Adult↗

Prehospital transcutaneous cardiac pacing for symptomatic bradycardia.

We studied patients with symptomatic bradycardia to determine the importance of presenting hemodynamic status and prehospital transcutaneous cardiac pacing (TCP) upon patient survival. Of 51 patients with witnessed cardiovascular decompensation and initial bradycardia, 27 (53%) received TCP. There were no significant differences between the paced patients and those without TCP for mean times from collapse until cardiopulmonary resuscitation, paramedic arrival and a paceable rhythm, or from paramedic arrival until a paceable rhythm. Overall, emergency department arrival with a palpable pulse (26% in paced vs 13% in nonpaced group; P = 0.20) and survival to hospital discharge (15% in paced vs 0% nonpaced group; P = 0.07) tended to be better for the paced group. No patient without a palpable pulse on paramedic arrival survived to leave the hospital. Of patients with a palpable pulse upon paramedic arrival, survival to hospital discharge was greater for the paced group (80% in paced vs 0% in nonpaced group; P = 0.024). TCP appears to be most beneficial in those patients with bradycardia who have a palpable pulse when first seen.

Aged↗

Closed thoracic cavity lavage in the treatment of severe hypothermia in human beings.

Life-threatening hypothermia can be treated by active and passive rewarming techniques, the treatment of choice being partial cardiopulmonary bypass. The use of closed thoracic cavity lavage has been evaluated in animals, but no formal presentations in human beings have been reported. We report two cases in which rapid rewarming in severe hypothermia was accomplished when cardiopulmonary bypass was not available.

Adult↗

A continuous hemorrhage model of fatal hemorrhagic shock in swine.

We studied the effect of bleed rate on survival time and hemodynamics in a continuous hemorrhage model of fatal hemorrhagic shock in lightly anesthetized swine. Fasted immature swine (12-16 kg) were sedated with intramuscular (i.m.) ketamine, endotracheally intubated, anesthetized with halothane (0.75%), nitrous oxide, and oxygen, and then prepared for experimentation by placement of a pulmonary artery thermodilution catheter, femoral arterial and venous catheters, and by splenectomy. After instrumentation, halothane was discontinued and sedation was maintained with nitrous oxide and intravenous lorazepam. Thirty minutes later, the animals were bled continuously at 1.0 ml/kg per min (n = 8, Group I) or 1.25 ml/kg per min (n = 8, Group II) by a roller pump connected to the femoral arterial catheter. Hemodynamic parameters were recorded every 15 min until death occurred. Mean survival time was 50.2 +/- 3.0 min in Group I and 39.8 +/- 3.2 min in Group II (P less than 0.001). There was a stepwise decrease in blood pressure and cardiac index consistent with progressive hemorrhagic shock. This model results in reproducible survival times with small standard deviations. Although the animals are lightly anesthetized and the experiments are performed acutely, the hemodynamic responses and survival times observed are similar to those reported in previous studies of chronically instrumented, unanesthetized swine. This model may be more practical than unanesthetized, chronically instrumented swine models for evaluating the effects of various interventions on survival time and hemodynamics in acute hemorrhagic shock.

Animals↗

Intravenous fluid therapy in the prehospital management of hemorrhagic shock: improved outcome with hypertonic saline/6% Dextran 70 in a swine model.

The small quantities of 7.5% hypertonic saline (HTS) in 6% Dextran 70 (DEX 70; Travenol Laboratories, Deerfield, IL) required to produce marked improvement in tissue perfusion may make it an ideal solution for the prehospital management of hypotensive trauma patients. This study shows that the initial treatment of porcine hemorrhagic shock with 7.5% HTS/6% DEX 70 results in significantly improved hemodynamics and higher survival rates than those seen in animals treated with normal saline. These results are very encouraging and dictate the need for evaluation in human trials.

Animals↗

Early versus late fluid resuscitation: lack of effect in porcine hemorrhagic shock.

The benefit of IV fluid therapy in the prehospital management of hemorrhagic shock is unproven. We used a reproducible, lightly anesthetized model of porcine continuous hemorrhage to evaluate the usefulness of pre-hospital IV fluid therapy. Incorporated into the model were time delays associated with ambulance request and dispatch, patient evaluation and treatment, and transport to the hospital in the average urban prehospital care system. Treatment occurred concurrently with hemorrhage. Twenty-eight immature swine (15 to 20 kg) were bled at a rate of 1.25 mL/kg/min. Animals in the prehospital IV group (n = 14) received fluid resuscitation at 1 mL/kg/min beginning 20 minutes after initiation of hemorrhage; those in the in-hospital IV group (n = 14) received fluid at a rate of 3 mL/kg/min beginning 35 minutes after hemorrhage. Both groups received blood and saline at 3 mL/kg/min 45 minutes after hemorrhage began, and both groups had hemorrhage controlled 25 minutes after simulated hospital arrival. Survival was 57% in both groups, and there were no statistically significant differences seen in measured hemodynamic or biochemical parameters. We conclude that early administration of IV normal saline has no effect on hemodynamics or survival in this porcine hemorrhagic shock model simulating an urban prehospital care system.

Animals↗

Prehospital use of neuromuscular blocking agents in a helicopter ambulance program.

We prospectively studied the use of succinylcholine chloride and pancuronium bromide by the physician/nurse flight team of our hospital-based helicopter ambulance service. Patients who received these agents at the scene of an accident (prehospital group, n = 39) were compared with patients who were paralyzed by the flight team in the emergency department of transferring hospitals (control group, n = 35). By protocol, succinylcholine was used primarily for endotracheal intubation and pancuronium for prolonged paralysis after endotracheal intubation. Seventy-four patients received one or both agents. Overall, 61 of 74 patients had intracranial pathology as their primary diagnosis (82%). Endotracheal intubation was the primary indication for paralysis in the majority of patients (67 of 74), although intracranial pressure control, ventilation, agitation control, and seizure control were frequent secondary indications. Prior intubation attempts had failed in 40 of 74 patients (54%). After paralysis, intubation was successful in 68 of 71 patients (96%). Serious complications (ie, dysrhythmia requiring drug therapy) occurred in three patients but resolved with appropriate therapy in each case. Minor complications (ie, dysrhythmia not requiring drug therapy, histamine flush, infiltrated IV line) occurred in 18 patients. There was no significant difference in successful intubation or complication rate between the prehospital and control group. Paralysis allowed airway stabilization in a significant number of critically ill patients who could not otherwise be endotracheally intubated, with a lower incidence of complications than has been previously reported for ED patients. These results suggest that neuromuscular blocking agents can be used safely and effectively at accident scenes by a physician/nurse team.

Adolescent↗

Succinylcholine-assisted intubations in prehospital care.

Although endotracheal intubation is considered the optimal technique for airway management in critically ill patients, performance of this task in the prehospital setting is at times difficult due to increased masseter muscle tone, vocal cord spasm, or patient combativeness. Use of short-acting paralyzing agents by paramedics to facilitate intubation in these situations is an uncommon practice. We report the recent experience of an emergency medical service system that has used succinylcholine (SUX) for more than ten years. We reviewed prehospital patient intubations for two years; 215 patients were intubated by paramedics without the use of SUX and 95 patients were intubated with the use of SUX. The patient group intubated with SUX was characterized by a greater percentage of women (48% vs 35%; P less than .05), a higher mean Glasgow Coma Scale score (8.6 vs 3.4), fewer intubations for cardiac arrest (3% vs 81%), and more hospital survivors (58% vs 24%; P less than .005). The groups were not different with respect to mean age or frequency of trauma. Paramedics chose to use SUX in 69% of nonarrested patients requiring intubation. SUX-assisted intubation was used most often for the indications of airway protection and respiratory distress. Review of hospital records showed no difference between the groups for frequency of either aspiration pneumonia or mechanical ventilation in patients surviving to hospital admission. No patient receiving SUX required emergency cricothyrotomy, nor was esophageal intubation noted in either group. Succinylcholine-assisted intubation was used safely and selectively by the paramedics in this EMS system to permit airway control and ventilation of patients with more difficult intubations.

Adolescent↗

The effect of ethanol on survival time in hemorrhagic shock in an unanesthetized swine model.

Controversy exists as to whether ethanol intoxication causes exaggerated hypotension or increased mortality during hemorrhagic shock. Previous studies have used anesthetized animals. This limits data interpretation as anesthetic agents, particularly pentobarbital, have well-documented effects on hemodynamics and the response to hemorrhage. We studied the effects of moderate ethanol intoxication on blood pressure and survival time during fatal hemorrhagic shock in unanesthetized swine. Immature female swine weighing 15 to 20 kg were splenectomized and instrumented with chronic indwelling aortic catheters, right atrial catheters, and gastrostomy tubes. Four to seven days later the unanesthetized animals underwent hemorrhagic shock. Thirty minutes prior to the start of hemorrhage, the experimental group (n = 8) received 3 mL/kg of 100% ethanol mixed as a 1:3 solution with water through a gastrostomy tube. The control group (n = 8) received an equal amount of water. The distal aortic catheter was connected to a roller pump and blood was removed at a rate of 1 mL/kg/min until the animal died. Arterial pressure, heart rate, lactate ethanol and glucose levels, hematocrit, and arterial blood gases were measured in both groups at baseline and every 15 minutes thereafter. A mean ethanol level of 1,500 to 1,700 micrograms/mL was produced in the experimental group from baseline through 60 minutes. Data were analyzed using Student's two-tailed t test, and analysis of variance for repeated measures. There was no significant difference in survival time between the control (63.1 +/- 2.8 min) and ethanol (59.9 +/- 5.9 min) groups. Systolic blood pressure was significantly lower in the ethanol group after 15 minutes of hemorrhage (81 +/- 22 to 59 +/- 14 mm Hg, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Hemodynamic and metabolic effects of ethanol in canine hemorrhagic shock.

Ethanol has been reported to cause myocardial suppression, exaggerated hypotension, and increased mortality in various animal models of hemorrhagic shock. Previous studies have not used a fixed-volume graded hemorrhage model and have not monitored cardiac output or metabolic parameters such as serum glucose and lactate levels. We studied hemodynamic and metabolic changes after administration of ethanol in a 50% graded hemorrhage model in conditioned, anesthetized beagles after orogastric ethanol loading. The hemorrhage was done over a 60-min period followed by a 90-min stabilization period. The ethanol group (n = 6) had significantly higher heart rates during the stabilization period. Mean arterial pressures (MAP) were lower in the ethanol group during the stabilization period. The change from baseline MAP 30 min after hemorrhage was -31% in the control group and -53% in the ethanol group (P less than .05 using Wilcoxon ranked sum test). Serum glucose and lactate levels were higher in the ethanol group. These results indicate that ethanol impairs hemodynamics and alters glucose and lactate metabolism in dogs in the fixed-volume graded hemorrhage model. The effect of these changes on morbidity and mortality remains to be determined.

Animals↗

Effects of dichloroacetate in spinal stroke in the rabbit.

High levels of brain lactate may contribute to cellular death and dysfunction in acute cerebral ischemia. Although sodium dichloroacetate (DCA) has been shown to lower brain lactate in incomplete cerebral ischemia, functional outcome has not been assessed with DCA. We examined the effects of DCA treatment on functional neurologic outcome using a previously developed model for "spinal stroke" in the rabbit. Thirty male New Zealand white rabbits weighing 1.3-2.8 kg were studied. After anesthesia with 15-40 mg/kg pentobarbital IV, a laparotomy was performed and the aorta exposed. A metal clamp was placed on the aorta just distal to the left renal artery for 20 minutes and then removed. The abdominal wound was closed in two layers. Animals then received either 2cc normal saline (n = 15) or 300 mg/kg DCA in 2cc normal saline (n = 15) over 10 minutes. The animals were returned to their cages when awake and were examined at 24 hours, 48 hours, and 72 hours for neurologic assessment. The exams were performed by a blinded examiner who was unaware of the treatment given. A three point ambulatory score (0 = can't walk, 1 = walk but not hop, 2 = hopping) and a two point activity score (0 = inactive, 1 = active) were used. At 24 hours, 67% of the DCA-treated animals were actively moving about compared to only 27% of the controls (P = 0.03; Fisher Exact Test). Ten of fifteen control animals were unable to walk, while only five of fifteen DCA-treated animals were unable to walk (P = 0.07). Sixty percent of the DCA animals were able to hop compared to 27% of controls (P = 0.06). These results suggest that DCA can reduce morbidity from spinal cord ischemia in the rabbit.

Acetates↗

Naloxone does not improve hemodynamics following graded hemorrhage in a canine model.

Two recent studies have demonstrated no improvement in hemodynamic parameters or survival following naloxone administration in hemorrhagic shock. This finding is in contrast to those of earlier studies, which consistently demonstrated a beneficial effect. The current study evaluated naloxone's ability to improve hemodynamics when administered following a fixed-volume hemorrhage, during a period of partial hemodynamic compensation. Thirteen conditioned beagles were anesthetized with pentobarbital (25 mg/kg intravenously), endotracheally intubated, and instrumented with a femoral arterial line and a pulmonary artery thermodilution catheter. Animals were then subjected to an estimated 50% graded hemorrhage (45 ml/kg) over one hour. Following hemorrhage, animals were observed for 90 minutes, then reinfused with shed blood over 30 minutes, and finally observed for an additional 60 minutes. Six animals received naloxone (2 mg/kg intravenously) 30 minutes after completion of hemorrhage and then 2 mg/kg/hr for the duration of the study. Seven control animals received an equivalent volume of saline. Heart rate, mean arterial pressure, central venous pressure, cardiac output, arterial and mixed venous blood gases, and serum lactate level were measured at regular intervals throughout the study. Cardiac index and systemic vascular resistance index were calculated at the same intervals. Overall, there were no statistically significant differences in the mean data values for mean arterial pressure, cardiac index, systemic vascular resistance index, or lactate, although lactate values were consistently higher in the naloxone group (two-tailed independent Student's t test). We conclude that naloxone does not significantly improve hemodynamics when administered after a fixed-volume hemorrhage.

Animals↗

Effects of dichloroacetate administration during fatal hemorrhagic shock in immature swine.

During hemorrhagic shock, decreased perfusion and poor tissue oxygenation lead to increased lactate production. Previous animal studies have suggested that sodium dichloroacetate (DCA), an agent that decreases lactate production, can improve hemodynamics and survival when administered after severe hemorrhage. We used an unanesthetized porcine hemorrhagic shock model to assess the effect of DCA on survival time when administered during fatal hemorrhage. Immature female swine weighing 14 to 20 kg were splenectomized and instrumented with chronic indwelling aortic and right atrial catheters one week prior to hemorrhage. On the day of the experiment, the unanesthetized animals' aortic catheter was connected to a roller pump and blood was removed at a rate of 1.0 mL/kg/min until death occurred. Experimental animals (n = 8) received sodium dichloroacetate (25 mg/mL distilled water) 100 mg/kg IV bolus beginning 15 minutes after the start of hemorrhage followed by a 3 mg/kg/min constant IV infusion. Control animals (n = 8) received an equal volume of normal saline. Arterial pressure, heart rate, blood gases, serum lactate, and serum glucose were measured at baseline and every 15 minutes during hemorrhage. There were no significant differences in survival time (controls, 63 +/- 2.8 min; DCA-treated, 60 +/- 3.7 min), lactate levels, or blood pressures between the two groups. These results suggest that DCA does not decrease serum lactate or improve survival time when administered during ongoing severe hemorrhagic shock. Further study should be directed at the effects of DCA as an adjunctive treatment after hemorrhage has been controlled and tissue perfusion restored.

Acetates↗