Biomedical subjects

K Waxman

Publications and source records attributed to K Waxman.

At least 55 records · Page 3Linked to original sources

PubMed1993

Orotracheal intubation in trauma patients with cervical fractures.

OBJECTIVE: To evaluate orotracheal intubation with in-line stabilization of the cervical spine for emergency airway treatment of trauma patients with cervical spine injuries. DESIGN: Of 7518 trauma patients examined, 81 patients with cervical spine injuries received emergency orotracheal intubation. All intubations were performed by experienced anesthesiologists, with a separate individual maintaining in-line stabilization. Neurologic examination was documented before and after intubation. RESULTS: Peripheral neurologic deficit was present from the outset in 20 patients. There were unstable cervical fractures in 38 patients with no neurologic deficit. Twenty-three patients were neurologically intact with fractures that were later judged stable. In no instance was there a deterioration of neurologic status following intubation. Peripheral neurologic deficits improved after intubation in four patients. CONCLUSION: Orotracheal intubation, performed with manual in-line stabilization by trained and experienced personnel, is a safe emergency procedure in patients with cervical fractures.

Accidents, Traffic↗

PubMed1993

Hypoxia induces a human macrophage cell line to release tumor necrosis factor-alpha and its soluble receptors in vitro.

Tissue hypoxia following hemorrhage and trauma is a possible initiating factor of the generalized inflammatory response seen after shock. The role of hypoxia in the release from a human monocyte cell line (THP-1) of tumor necrosis factor-alpha (TNF alpha) and its soluble membrane receptors (TNF alpha R) in-vitro is investigated in this study. Flat-bottom plates with 500,000 THP-1 cells/ml were placed in air-tight sealed boxes and exposed to hypoxia (O2 = 1%) or controls (O2 = 9%) for up to 24 hr. Supernatants were tested for TNF alpha, as well as 55- and 75-kDa soluble receptors for TNF alpha, by ELISA. Cell viability was assessed by vital dye uptake and was found to be maintained throughout hypoxic exposure. Medium pH levels were within normal range. In eight experiments conducted in duplicate, minimal change over 24 hr occurred in control samples. Control mean and SD were: TNF alpha = 12.0 +/- 4.2, 55-kDa R = 34.6 +/- 2.03, and 75-kDa R = 38.88 +/- 9.68 pg/ml. During hypoxia, TNF alpha was released as early as the first 30 min of exposure (41.3 +/- 2.3 pg/ml) with a small peak at 1 hr (52 +/- 5.0 pg/ml) and a later more pronounced peak at 18 hr (526 +/- 48 pg/ml). Both 55- and 75-kDa R were released by the hypoxic monocytes; release was progressive and was maximal at 24 hr in this study. Maximal release value of 55-kDa R was 236 +/- 15 pg/ml, while for 75-kDa R it was 2450 +/- 63 pg/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Capillaries↗

PubMed1993

Tumor necrosis factor and monocytes are released during hemorrhagic shock.

Tumor necrosis factor (TNF) is a key mediator involved in many physiologic processes including immunity, inflammation, and metabolism. A relationship between TNF and hemorrhagic shock has not been clearly demonstrated. To help understand the role of TNF in hemorrhagic shock we developed a hemorrhagic shock model to measure TNF and monocyte levels during hemorrhage and resuscitation. Male Sprague-Dawley rats were anesthetized and subjected to a 50% blood loss (30 ml/kg) over 2 min and left in shock for 58 min. The animals were then resuscitated with two times blood loss (60 ml/kg) using lactated Ringers over 1 h. This model results in 75% mortality within 3 days (LD 75). Blood samples (2 ml) were obtained at intervals during shock and resuscitation, and assayed for TNF concentrations and white blood cell counts. Despite a marked fall in total leukocytes (24,600 pre-hemorrhage to 11,300 post-hemorrhage, P < 0.005), monocytes increased in percentage and in total count. Blood levels of TNF were initially undetectable but rose within 10 min after hemorrhage, peaked at 30 min after hemorrhage, and then became undetectable during resuscitation. In this model, macrophages and TNF are released into the circulation after hemorrhagic shock. TNF may play a role as a mediator in the pathophysiology of hemorrhagic shock.

Animals↗

PubMed1993

Pentoxifylline alone versus pentoxifylline combined with superoxide dismutase prolongs survival in a rat hemorrhagic shock model.

Pentoxifylline (PTX) and superoxide dismutase (SOD) have each proven effective in improving survival when administered during resuscitation in animal models of hemorrhagic shock. This study was conducted to determine if PTX and SOD combined would have synergistic effectiveness in the treatment of hemorrhagic shock. Sprague-Dawley rats (n = 40) were phlebotomized at 25 ml/kg for 2 min, then subjected to a 45-min ischemic period, and resuscitated with lactated Ringer's solution (LR) (50 ml/kg) over 1 h. This model resulted in 70% mortality over 72 h when resuscitation was with LR alone. Animals were randomized into groups to receive one of the following agents during resuscitation: PTX in LR, SOD in LR, a combination of PTX and SOD in LR, or LR alone. PTX or SOD alone were effective in prolonging survival. However, the combination of PTX and SOD did not prolong survival above LR control.

Animals↗

PubMed1993

Continuous arteriovenous hemodiafiltration in postoperative and traumatic renal failure.

Management of acute renal failure (ARF) in surgical patients has relied on supportive measures including hemodialysis and peritoneal dialysis. An alternative technique currently available is continuous arteriovenous hemodiafiltration (CAVH-D). Records of 44 surgical patients with ARF who were treated with CAVH-D in our surgical intensive care unit from 1989 to 1992 were reviewed. Thirty-five patients underwent emergency operations, and 4 patients underwent elective operations. Thirty-three patients were hemodynamically unstable immediately prior to the institution of CAVH-D, making hemodialysis a contraindication. A total of 565 CAVH-D days with an average of 13 days per patient were evaluated. Seventeen patients survived, with recovery of renal function in 13 patients. Vascular access was obtained via 227 percutaneous femoral catheters and 4 Scribner shunts. Seven vascular complications occurred, including arteriovenous fistula, pseudoaneurysm, limb ischemia, femoral artery hemorrhage, and femoral vein thrombosis. Based on these data, we conclude that CAVH-D is a safe and effective alternative in surgical patients with ARF.

Acute Kidney Injury↗

PubMed1993

Trauma causes early release of soluble receptors for tumor necrosis factor.

The importance of tumor necrosis factor (TNF) in the pathophysiology of trauma and hemorrhagic shock is not known. In addition, TNF bioactivity may be modulated by soluble forms of the 55-kd and 75-kd membrane receptors (TNFR). This study was undertaken to determine circulating levels of TNF and TNFR after trauma. Nine severely injured male patients were studied. The mean age was 30 +/- 10 years (range, 15-45). The mean Injury Severity Score (ISS) was 31.3 +/- 17.6 (range, 10-59), and the mean Revised Trauma Score (RTS), 5.7 +/- 2.2 (range, 0.7-7.8). Serum was obtained immediately upon arrival at our trauma center, within 1 hour of injury. The TNF and TNFR levels in the serum were measured using ELISA techniques. After trauma, 55-kd and 75-kd TNFR levels were significantly elevated above those of controls (6.99 +/- 4.57 ng/mL and 5.42 +/- 1.88 ng/mL, respectively, p < 0.01); TNF levels were not increased. Patient serum containing TNFR inhibited in vitro TNF cytotoxicity and correlated with 55-kd TNFR levels (p < 0.05). We conclude that TNF is a strong releasing factor for TNFR; the presence of TNFR may be indirect evidence that TNF is present after trauma, despite low measured levels. Both TNF and TNFR may be more important in trauma and hemorrhagic shock than previously thought.

Adolescent↗

PubMed1993

Vascular complications of continuous arteriovenous hemofiltration in trauma patients.

Continuous arteriovenous hemofiltration (CAVH) has recently become useful in the treatment of acute renal failure following trauma. It allows continuous volume removal and avoids the acute hemodynamic changes often seen with hemodialysis. To determine the risks of CAVH catheters, the records of trauma patients undergoing CAVH from August 1989 through May 1992 were reviewed. Of 4685 trauma patients, 29 developed renal failure requiring dialysis, with 26 managed with CAVH. Vascular access was obtained via 126 percutaneous 8F femoral arterial and venous catheters (64 arterial, 62 venous) and four Scribner shunts. There was a total of 309 CAVH-D days, with an average of 11.9 days per patient. Complications included one femoral arteriovenous fistula, one pseudoaneurysm, and one deep venous thrombosis, resulting in a 3.1% (2 of 64) arterial complication rate and a 1.6% (1 of 62) venous complication rate. The incidence of arterial complications compares with that of angiography, but complications were major and required surgery. Alternative techniques such as continuous venovenous hemofiltration may prove beneficial.

Acute Kidney Injury↗

PubMed1993

Absorption of insulin in the peritoneal cavity in a diabetic animal model.

This study was conducted to determine if different anatomical sites within the peritoneal cavity have different capacities for portal insulin absorption. Diabetic male Sprague-Dawley rats were studied. They were anesthetized and injected with streptozotocin. Blood glucose was measured before and after insulin (1 U/kg) was applied directly to the omentum, serosal surface of cecum, or parietal peritoneum or injected subcutaneously. In a control group, blood glucose was measured at intervals without administering insulin. In addition, insulin labeled with radioactive iodine (125I) was applied to the same three locations in the peritoneal cavity or injected intravenously. Animals were sacrificed at 1, 5, 15, or 30 mins, and radioactivity was measured in excised livers and in blood samples. Blood glucose in the omental group responded to insulin with a greater hypoglycemic effect than in the peritoneal and control groups. The percentage of radioactivity recovered in liver was significantly higher in the omental than in the serosal and peritoneal groups at 1 and 5 mins. The ratio of liver-to-blood radioactivity was also significantly higher in omental than in serosal and peritoneal groups and higher in the serosal than in the peritoneal group at 5 mins. The data suggest that, in this model, the omentum is a better site for insulin absorption than serosa or parietal peritoneum and that significant portal venous absorption of insulin occurs.

Animals↗

PubMed1993

Long-term safety and efficacy of programmable implantable insulin delivery systems.

OBJECTIVES: Since only short-term studies of continuous intraperitoneal insulin infusion (CIPII) therapy using implantable programmable insulin delivery systems have been performed to show this method of diabetes therapy to be safe and efficacious, we have performed long-term studies to assess its safety and efficacy. RESEARCH DESIGN AND METHODS: For 78 patient-years of follow-up, we have longitudinally studied the incidence of diabetic ketoacidosis and severe hypoglycemia in 25 type 1 diabetic patients treated with CIPII. We also compared, cross-sectionally, the long-term safety and efficacy of CIPII to intensive subcutaneous insulin therapy using intermittent injections or continuous subcutaneous insulin infusion. Finally, we examined the relationship between glycated hemoglobin levels and the standard deviation of daily blood glucose excursion. RESULTS: Cross-sectional analysis revealed similar degrees of metabolic control accompanied by significantly decreased rates of both ketoacidosis (0.013 events/patient/year) and severe hypoglycemia (0.05 events/patient/year) during CIPII compared to intermittent injections and continuous subcutaneous insulin infusion therapy. A four-fold decrease in the rate of severe hypoglycemia was observed during longitudinal comparison of pre- and post-implantation complication rates. A relationship was also shown between decreased levels of mean glycated hemoglobin and the standard deviation of blood glucose excursions during CIPII therapy. CONCLUSIONS: Our data demonstrate that long-term therapy with CIPII is as effective as other methods in achieving near-normal levels of glycated hemoglobin, which in CIPII is associated with a decreased standard deviation of blood glucose excursions. Further, CIPII using implantable programmable insulin delivery systems is the safest method described for intensive insulin therapy in home blood glucose monitoring type 1 diabetic patients.

Adolescent↗

PubMed1993

Superoxide dismutase and allopurinol improve survival in an animal model of hemorrhagic shock.

We studied the efficacy of resuscitation with antioxidants in an animal model of hemorrhagic shock. Male Sprague-Dawley rats were anesthetized, and 27 mL/kg of blood was withdrawn from the carotid artery over 2 minutes. The animals remained in hemorrhagic shock for 45 minutes, followed by 1 hour of resuscitation. Experimental groups were as follows: 1) 15,000 u/kg superoxide dismutase (SOD) in 54 mL/kg lactated Ringer (LR); 2) 175,000 u/kg catalase (CAT) in LR; 3) 15,000 u/kg SOD+175,000 u/kg CAT in LR; 4) allopurinol in LR; 5) deferoxamine bound to pentafraction (DFO), 27 mL/kg; 6) pentafraction alone; and 7) LR alone. Compared with resuscitation with LR alone, SOD and allopurinol improved survival over 72 hours, P < 0.05. Survival with SOD+CAT was not different from LR alone. Deferoxamine bound to pentafraction did not increase survival over that with pentafraction alone. CAT had increased mortality compared to LR, P < 0.01. The efficacy of both SOD and allopurinol in decreasing mortality suggests the importance of superoxide radicals after hemorrhagic shock and resuscitation. These and other antioxidants are potential therapeutic agents in the clinical setting of trauma and hemorrhagic shock.

Allopurinol↗

PubMed1993

Emergency thoracotomy with lung resection following trauma.

Over a 7-year period, 9443 trauma patients were evaluated with 2934 (31%) sustaining chest trauma. Of these, 347 (12%) patients required thoracotomy, with 12 patients undergoing emergency lung resection. Mean age was 23.1 years with mean Injury Severity Score of 32. Mechanism of injury was blunt in three (25%), gunshot wound in seven (58%), and stab wound in two (17%). Associated injuries included head injury in two (17%), intra-abdominal injury requiring laparotomy in four (33%), cardiac injury in three (25%), and great vessel injury in one (8%). Indications for operation included persistent hemorrhage in 11 and suspected tracheobronchial disruption in one. Non-anatomic lung resection was performed in five patients, lobectomy in three patients, and pneumonectomy in four patients. Overall mortality was 33 per cent: 20 per cent for non-anatomical lung resection, 33 per cent for lobectomy, and 50 per cent for pneumonectomy. All survivors fully recovered except for one patient with an associated head injury. Our experience supports the selective use of lung resection, including pneumonectomy, to immediately control hemorrhage and to impact survival in severe chest trauma.

Abdominal Injuries↗

PubMed1992

Diagnosis of myocardial contusion. Quantitative analysis of single photon emission computed tomographic scans.

Prior studies from our institution have shown that single photon emission computed tomography is sensitive (100%) in predicting patients at risk for serious arrhythmias. However, the positive predictive value is low (15% to 20%). The purpose of this study was to determine if quantitative analysis of single photon emission computed tomographic defects could improve predictive value. One hundred seventy-five patients with positive single photon emission computed tomographic scans were studied. One hundred two patients developed arrhythmias, 42 of which were ventricular. Arrhythmias were associated with all defect loci and all defect sizes. The incidence of arrhythmias did increase with increasing size. Patients were at risk for arrhythmias up to 72 hours after trauma. The value of single photon emission computed tomography is its ability to predict patients at risk for arrhythmias. This study shows that any single photon emission computed tomographic defect, regardless of location or size, is a significant predictor of arrhythmias.

Adolescent↗

PubMed1992

Implantable programmable insulin pumps for the treatment of diabetes.

Implantable programmable pump systems for insulin delivery to the peritoneal cavity or for intravenous insulin delivery have been recently developed. Thirty-one pumps were implanted in 25 patients between 1987 and 1991. At this writing, 76% of patients had functioning pumps. Ninety-two percent of pumps were functioning at 1 year; 89% at 2 years; and 50% at 3 years. No life-threatening complications, either surgical or metabolic, developed. However, 18 patients required 23 outpatient procedures for maintenance of pump function or for pump removal. Metabolic improvement was evidenced by mean and standard deviation of blood glucose levels and by glycosylated hemoglobin levels.

Abdominal Muscles↗

PubMed1992

Randomized comparison of metabolic control achieved by intraperitoneal insulin infusion with implantable pumps versus intensive subcutaneous insulin therapy in type I diabetic patients.

OBJECTIVE: To compare intraperitoneal implantable insulin infusion (IP) to subcutaneous (SC) intensive insulin therapy. RESEARCH DESIGN AND METHODS: Twenty-one insulin-dependent (type I) diabetic patients aged 24-61 yr underwent a 3-mo treatment optimization using multiple SC daily injections or external pumps. Patients were then randomized (time 0 mo) to IP infusion using Infusaid-programmable pumps or continuation on SC intensive insulin for 6 mo. RESULTS: No differences were noted between study and control group data. However, longitudinal within-group comparisons from baseline showed that glycosylated hemoglobin improved to near-normal in both groups: IP, 9.0 +/- 0.5 vs. 7.8 +/- 0.6% (P less than 0.05) and SC, 8.4 +/- 0.5 vs. 7.5 +/- 0.3% (P less than 0.5) at 0 and 4 mo, respectively (normal less than 6.9%). The percentage of blood glucose tests greater than 11 mM at 0 and 6 mo was 28 +/- 5 vs. 16 +/- 4% in the IP group (P less than 0.05) and 22 +/- 5 vs. 24 +/- 7% in the SC group (NS). At 0 and 6 mo, the standard deviation of blood glucose values, an index of glycemic fluctuations, was 4.3 +/- 0.4 vs. 3.2 +/- 0.5 mM in the IP group (P less than 0.05) and 3.7 +/- 0.3 vs. 4.0 +/- 0.4 mM in the SC group (NS). Weight, insulin dosages, circulating lipid levels, and the frequency of severe hypoglycemic reactions and biochemical hypoglycemias were similar and did not change in the two groups. CONCLUSIONS: IP-implantable pumps compared with SC intensive insulin therapy have similar effects on most metabolic variables and are equally effective at achieving near-normal glycemic levels. Only longitudinal data suggest that IP treatment may be more effective at limiting glycemic fluctuations.

Adult↗

PubMed1992

Occult traumatic pneumothorax: immediate tube thoracostomy versus expectant management.

Occult pneumothorax is pneumothorax identified by computed tomography but not seen on conventional chest radiographs. Twenty-seven occult traumatic pneumothoraces in 26 patients were identified retrospectively at the authors' level I trauma center. Of these, 24 patients survived to discharge or transfer; 2 died of brain injury. Eleven patients were treated immediately with tube thoracostomy (TT) and 13 were observed with interval chest radiography. The authors' data support the conclusion that it is safe to withhold immediate TT in patients who are hemodynamically stable. Close clinical observation and interval chest radiography can identify those patients who require subsequent TT. Prospective study of larger numbers of patients is needed to confirm the safety and cost efficacy of this approach.

Adolescent↗

PubMed1991

Is early prediction of outcome in severe head injury possible?

To determine whether the outcome of patients with severe head injury could be predicted early after presentation to the hospital, the records of 306 trauma patients with head injury and Glasgow Coma Scale scores of 10 or less were reviewed. There was poor correlation between initial scores at patient arrival and eventual outcome, while scores 6 hours after presentation correlated better with eventual outcome. Many patients with scores as low as 3 had good neurologic recovery. Patient age, associated injuries, blood pressure, mechanism of injury, presence of spontaneous ventilation, and computed tomographic findings all affected survival. However, considering even these parameters, statistical analysis could not provide sensitive prediction of outcome, which we defined as identifying those patients who eventually had good recovery. We conclude that initial therapy should be aggressive for patients with severe head injury, regardless of initial neurologic status, because accurate prediction of outcome within 6 hours of presentation is impossible.

Adolescent↗

PubMed1991

Adequate resuscitation of burn patients may not be measured by urine output and vital signs.

OBJECTIVE: To compare vital sign and urine output monitoring of seriously burned patients with invasive monitoring during early resuscitation. DESIGN: Retrospective review. SETTING: A university hospital burn unit. PATIENTS: Fourteen seriously burned patients who had pulmonary arterial monitoring. Monitoring data were compared at baseline and after fluid challenges. RESULTS: There was no correlation between invasively derived physiologic variables and vital signs and urine output. Vital signs and urine output changed little after fluid challenge, while variables from invasive monitoring demonstrated significant change. In half of the patients, oxygen consumption increased after fluid challenge; vital signs and urine output did not distinguish these patients. CONCLUSIONS: The use of urinary output and vital signs to guide initial burn resuscitation may lead to suboptimal resuscitation. Invasive cardiorespiratory monitoring may be necessary to optimize resuscitation of seriously burned patients.

Adolescent↗

PubMed1991

Pentoxifylline in resuscitation of experimental hemorrhagic shock.

BACKGROUND: Pentoxifylline improves survival in animal models of hemorrhagic shock. The purpose of this study was to determine the physiologic effects of pentoxifylline in hemorrhagic shock that may be responsible for improved survival. METHODS: Randomized, prospective, blinded trials in Sprague-Dawley rats subjected to hemorrhage and resuscitation, with or without pentoxifylline. RESULTS: Pentoxifylline had no effect on BP or cardiac output. However, tissue oxygenation and oxygen consumption were increased with pentoxifylline resuscitation. Pentoxifylline resuscitation also significantly decreased polymorphonuclear leukocyte adhesiveness. CONCLUSIONS: Pentoxifylline improves tissue oxygenation and oxygen consumption posthemorrhage and this effect is not due to increased cardiac output. Therefore, it must be due to improved microcirculatory blood flow. This effect may be due to decreased polymorphonuclear leukocyte adhesiveness induced by pentoxifylline resuscitation.

Animals↗