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Biomedical subjects

J A Marx

Publications and source records attributed to J A Marx.

At least 73 records · Page 4Linked to original sources
PubMed1985

Utility of lavage alkaline phosphatase in detection of isolated small intestinal injury.

The ability of lavage alkaline phosphatase (LAP) to detect small intestinal injury was studied in 81 patients who underwent diagnostic peritoneal lavage following blunt and penetrating abdominal trauma. Patients with a grossly positive lavage were excluded. The LAP of five patients with small intestinal injury (79.0 +/- 41.7 IU/L) was significantly greater than in 76 cases without (1.2 +/- 0.4 IU/L; P less than .05). LAP greater than or equal to 3 was seen in six patients. Four had isolated small intestinal pathology, and one had combined small and large bowel injury. In three of these five, other lavage values were normal. One possible false positive occurred. The sensitivity of LAP greater than or equal to 3 (100%) exceeded that of usual lavage parameters in the detection of small intestinal injury. LAP may be a sensitive marker for small intestinal pathology in the immediate postinjury period.

Adolescent↗
PubMed1985

Limitations of computed tomography in the evaluation of acute abdominal trauma: a prospective comparison with diagnostic peritoneal lavage.

There has been recent enthusiasm for computed tomography (CT) to supplant diagnostic peritoneal lavage (DPL) in the detection of abdominal injuries. We prospectively compared CT to DPL following acute blunt trauma or stab wound to the abdomen. Patients with hemodynamic instability or overt signs of intraperitoneal pathology underwent urgent laparotomy and were excluded from study. Those with indications for DPL had lavage catheter insertion via open technique and attempted aspiration for gross blood. This was followed by contrast CT of the abdomen with a Technicare 2010 scanner. Lavage fluid, when required, was then instilled, recovered, and analyzed. CT interpretations were made in a blind fashion by a single staff radiologist. Decision for laparotomy was based on clinical, DPL, and CT data. In blunt trauma (N = 65), DPL detected 5/5 (100%) injuries discovered at laparotomy and CT 2/5 (40%). Following stab wounds (N = 35), DPL was true positive in 7/7 (100%) and CT in 1/7 (14.3%), with one false positive CT leading to negative laparotomy and one false positive DPL which prompted unnecessary celiotomy. Overall, the sensitivity of DPL was 100% versus 25% for CT and specificity 98.9% for both DPL and CT. In particular, CT missed seven solid visceral (five liver, two spleen), five hollow visceral, one major vascular, and three diaphragmatic lesions requiring operative intervention. In our experience, CT demonstrated an alarming incidence of false-negative studies. Given the widespread variability of CT equipment and personnel we would argue strongly against the use of CT alone in the evaluation of acute abdominal trauma and continue to support DPL as the most accurate and reliable instrument of detection.

Abdominal Injuries↗
PubMed1985

A comparison of PTV and endotracheal ventilation in an acute trauma model.

Percutaneous transtracheal ventilation (PTV) is an active airway management technique that may be an alternative to cricothyroidotomy in critically injured patients. A canine trauma model was devised to compare the ventilatory capacity and hemodynamic effects of PTV to endotracheal intubation. Mongrel dogs (25-37 kg), splenectomized 14 days previously, were anesthetized with pentobarbital and bled to a mean arterial pressure (MAP) of 20 mm Hg. Animals were maintained at this MAP for 1 hour, then resuscitated with simultaneous: a) aortic crossclamping via left thoracotomy, b) Ringer's lactate infusion, and c) active airway support. Control animals (N = 5), intubated with a cuffed endotracheal tube, were ventilated at a rate of 12 per minute, a tidal volume of 500 cc and an FIO2 of 60%. In study animals (N = 5), PTV, for a duration of 1 second, was instituted at the same rate and FIO2. There was no statistically significant difference between the two groups with regard to pO2, pCO2, pH, and hemodynamic parameters. PTV was also performed in the emergency department on four patients unresponsive to resuscitative thoracotomy for postinjury cardiac arrest. PTV rate was 12/minute; duration, 1 second; and FIO2, 100%. Mean values (+/- SEM) for pH, pO2, and pCO2 obtained after 15 minutes of PTV were 7.14 +/- 0.03, 322 +/- 49.5 torr, and 21.5 +/- 4.7 torr, respectively. PTV is comparable to endotracheal intubation with respect to oxygenation, ventilation and hemodynamic response (p greater than 0.05). Our preliminary clinical study corroborates its efficacy in the acute trauma setting and supports further clinical investigation.

Animals↗
PubMed1984

Accuracy of emergency radiograph interpretation by emergency physicians.

The incidence of abnormalities in 1,869 sets of radiographs was recorded, and the accuracy of the interpretation of these films by emergency physicians was assessed. Abnormalities were most frequent in hip/femur (52.5%), thoracic spine (46.7%), and shoulder (44.8%) films and least frequent in skull (5.7%), cervical spine (14.9%), and foot (15.7%) films. The accuracy of interpretation by emergency physicians for all categories of films was 93.6%, with 1.8% false positives and 4.6% false negatives. Overreading of abnormalities occurred most often in thoracic spine (12.5%) and hip/femur radiographs (9.1%). The incidence of missing existing pathology was highest for abdomen (40.0%) and knee (31.6%) films. The overall accuracy of the emergency physicians in interpretation of emergency films was excellent. Increased didactics in particular areas of interpretive inaccuracies should be considered.

Clinical Competence↗
PubMed1984

Case report: common femoral artery occlusion following blunt trauma in a child.

Vascular injury from blunt trauma is infrequently seen in children unless associated with major trauma. This case report is an example of a significant vascular injury in the setting of minor trauma. The consequences of missing such an injury as well as some of the difficulties encountered in establishing the diagnosis are discussed.

Child, Preschool↗
PubMed1984

Percutaneous transtracheal ventilation in a canine shock model with an open thorax.

This study evaluates the effectiveness of percutaneous transtracheal ventilation (PTV) in a canine shock model. Five mongrel dogs (25 to 35 kg), splenectomized two weeks prior to study, were anesthetized (pentobarbital, 22 mg/kg) and bled to and sustained at a mean arterial pressure (MAP) of 20 mm Hg for 60 minutes. Ringer's lactate was infused and the descending thoracic aorta was cross-clamped. Simultaneously, PTV was begun with 60% O2 through the cricothyroid membrane. Hemodynamic measurements and arterial blood gases were obtained at 0, 5, 15, and 30 minutes following the initiation of PTV. Orotracheal ventilation was then instituted in place of PTV and continued for 30 minutes, and measurements were repeated. Auto-transfusion was also begun at this time. During PTV, PO2 and PCO2 were adequate in all dogs at each interval. We conclude that PTV provides effective oxygenation and ventilation in dogs subjected to profound shock, thoractomy, and thoracic aortic cross-clamp.

Animals↗
PubMed1984

Naloxone: effects on hypoxic pulmonary vasoconstriction.

To determine the effect of naloxone on the hypoxic pulmonary vasoconstrictive response, six mongrel dogs were rendered hypoxic with 10% oxygen and were given either saline or naloxone. Following hypoxia all dogs had significant increases in mean pulmonary artery pressure (PAP) and pulmonary arterial resistance index (PARI) without changes in cardiac output or systemic blood pressure. Beta endorphins did not change at any time following hypoxia. Dogs receiving naloxone had significant lowering of PAP and PARI without changes in plasma beta endorphin levels. We conclude that naloxone attenuates hypoxic pulmonary vasoconstriction without measurable alterations of plasma beta endorphin levels.

Animals↗
PubMed1983

Protein electrophoresis of diagnostic peritoneal lavage in penetrating bowel injuries.

Protein electrophoresis was performed on the lavage effluent of dogs after isolated jejunal (N = 7) or transverse colon (N = 5) injuries and after sham operations (N = 5). The beta-globulin fraction was significantly elevated in the bowel-injured dogs as compared with the sham model. Protein electrophoresis may provide a useful diagnostic marker of hollow visceral injury.

Albumins↗
PubMed1983

Complications of intravenous phenytoin for acute treatment of seizures. Recommendations for usage.

Intravenous (IV) phenytoin sodium in small volumes of normal saline was administered in a municipal hospital emergency department for treatment of convulsions in 200 patients. A total of 72 complications developed in 51 patients. Twenty-nine complications were burning pain at the IV site, and 36 were related to excessive total dose of phenytoin and resultant drug intoxication. Seven other patients had cardiovascular complications, including hypotension and arrhythmias. These seven complications were related to high concentrations of drug administered at a rapid rate. Both the IV and cardiovascular complications promptly resolved when the IV rate was slowed or temporarily stopped. No patient died, and none was hospitalized because of a complication. The authors propose specific guidelines for the safe administration of IV phenytoin.

Adolescent↗
PubMed1983

Optimal phenotypic expression times for HPRT mutants induced in foreskin-, skin-, and lung-derived human diploid fibroblasts.

A series of paired lung- and skin-derived fibroblast cultures has been established from human embryonic tissues under carefully controlled, identical conditions, providing the unique opportunity to study differences between normal diploid fibroblast populations from skin and lung without the confusion of genetic differences between donors. To reliably assess differences in the induced mutation frequencies observed among different cell populations, optimal phenotypic expression times in the HPRT mutagenesis system were determined for neonatal foreskin, fetal skin, and fetal lung cultures. Cell populations were mutagenized with several doses of N-methyl-N'-nitro-N-nitrosoguanidine and were replated in 6-thioguanine selective medium at intervals over 14 days. Survivals following MNNG exposure ranged from 1.6% to 45.5%. For all doses and survivals tested a 7-day expression period was the optimal value for cultures from the three different tissue sources in six independent experiments. Mutant frequency data derived from untreated control populations confirmed that spontaneous mutations during the expression period contributed negligibly to the final mutant frequency. Differences between the mutation frequencies obtained using an in situ and a replating protocol were approximately twofold for lung-, skin-, and foreskin-derived cultures.

Cell Line↗
PubMed1983

Peritoneal lavage in penetrating injuries of the small bowel and colon: value of enzyme determinations.

The value of lavage alkaline phosphatase determinations following hollow visceral injury was studied. Twenty-nine mongrel dogs were subjected to partial transection of the small intestine or colon, or underwent sham laparotomy. Sequential diagnostic peritoneal lavage was performed. At one hour post injury the lavage red cell count, white cell count, and amylase levels were within normal limits in each group. The lavage alkaline phosphatase, however, was markedly elevated in both bowel-injured groups compared with the sham group. In the five-hour lavage, red cell counts and amylase levels remained normal. White cell counts were now elevated in all three groups, but the results did not distinguish the intestinal injury from the sham model. Lavage alkaline phosphatase was again significantly increased in the injured groups versus the sham model. Serum alkaline phosphatase and amylase levels were normal in all study groups at baseline and one and five hours post injury. This canine study demonstrates the utility of peritoneal lavage alkaline phosphatase levels in identifying isolated small intestine and colon injuries that were otherwise undetected by red cell, white cell, and amylase determinations.

Alkaline Phosphatase↗
PubMed1983

The effects of high pass filtered speech on speech discrimination.

This study was designed to determine the intelligibility of speech at two intensity levels using two different conditions (broad band and high pass filtered speech) and to determine the vowels and consonants most affected by the conditions imposed. The ten subjects were all stimulated with 50 words of the CID W-22 series at two levels of intensity (30 db SL and 15 dB SL) each in the filtered and broad-band (unfiltered) conditions. The results tended to indicate that the type of condition (filtered or unfiltered) did not affect the speech comprehension until the intensity of the filtered signal approached 15 dB SL. It was also determined that consonants and vowels identification were only slightly affected by filtering if the intensity of the signal is above 15 dB SL.

Adult↗