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Biomedical subjects

S M Cohn

Publications and source records attributed to S M Cohn.

At least 55 records · Page 3Linked to original sources
PubMed1997

Resuscitation of pulmonary contusion: effects of a red cell substitute.

OBJECTIVE: To determine the impact of a vasoactive red cell substitute, diaspirin cross-linked hemoglobin, on respiratory derangements after traumatic lung injury. DESIGN: Randomized, controlled animal experiment. SETTING: Large-animal laboratory. SUBJECTS: Mechanically ventilated, anesthetized young Yorkshire male swine (15 to 20 kg). INTERVENTIONS: Pigs (n = 6/group) received two pneumatic blasts to the right thoracic cage at baseline, were hemorrhaged 30 mL/kg from t = 0 to 20 mins, resuscitated with 0.9% saline (group 1, 90 mL/ kg) or diaspirin cross-linked hemoglobin (group 2, 15 mL/kg) from t = 20 to 40 mins, and then observed to t = 240 mins. MEASUREMENTS AND MAIN RESULTS: Serial pulmonary and systemic hemodynamic measurements, total thoracic compliance assessment, spiral three-dimensional computed tomography scan, and lung weights (n = 3/group) were used to assess lesion size and lung water. Mean arterial pressure was restored in both animal groups. Mean pulmonary arterial pressure was significantly higher after resuscitation in animals receiving the red cell substitute. Oxygenation worsened mildly in both groups. Compliance diminished in both groups but was significantly worse at the end of the experiment in animals infused with diaspirin cross-linked hemoglobin. Right lung weights and right thoracic computed tomography scan volume were higher with diaspirin cross-linked hemoglobin than with saline. CONCLUSIONS: After pulmonary contusion, resuscitation with diaspirin cross-linked hemoglobin led to pulmonary hypertension, greater pulmonary contusion lesion size, and stiffer lungs in this porcine model.

Animals↗
PubMed1997

Early fracture fixation may be deleterious after head injury.

OBJECTIVE: To determine the neurologic risks associated with early fracture fixation (FF) in multitrauma patients with head injuries. METHODS: We reviewed 33 blunt trauma patients with significant closed head injuries (Abbreviated Injury Scale (AIS) score > or = 2) requiring operative FF. Nineteen patients underwent early FF defined as < or = 24 hours after injury, and 14 patients underwent late FF defined as > 24 hours after injury. The two groups were well matched in regards to age, 40.3 years (range, 8-88 years) versus 36.4 years (range, 8-75 years), admission Glasgow Coma Scale score (12 +/- 4 vs. 11 +/- 5), and Injury Severity Score (25 +/- 10 vs. 27 +/- 12). Additionally, the groups had similar neurologic and orthopedic injury scores (AIS-CNS score = 3.3 +/- 0.9 vs. 3.1 +/- 0.9, AIS-Ortho score = 3.0 +/- 0.9 vs. 2.9 +/- 0.7). Data were collected concerning the volume of fluid resuscitation, neurologic complications, and clinical outcomes. RESULTS: The early FF group received significantly more fluids in the first 48 hours (14.0 +/- 10.2 vs. 8.7 +/- 3.5 liters, p < 0.05). The early group trended towards a higher rate of intraoperative hypotension (systolic blood pressure < 90 mm Hg, 16% vs. 7%) and intraoperative hypoxia (O2-Saturation < or = 90, 11% vs. 7%). The neurologic complication rate was similar in the two groups (early FF = 16% vs. late FF = 21%), but the average discharge Glasgow Coma Scale score was lower in the early group (13.5 +/- 3.7) when compared with the late FF patient group (15.0 +/- 0.0). CONCLUSIONS: Early FF leads to greater fluid administration in patients with head injuries. Hypoxemia and hypotension, risk factors for secondary brain injury, may contribute to a poor neurologic outcome after early fixation. Prospective studies evaluating the impact of the timing of FF on head injury are indicated.

Adolescent↗
PubMed1997

Pulmonary contusion: review of the clinical entity.

Pulmonary contusion is a common lesion occurring in patients sustaining severe blunt chest trauma. Alveolar hemorrhage and parenchymal destruction are maximal during the first 24 hours after injury and then usually resolve within 7 days. The diagnosis of traumatic lung injury is usually made clinically with confirmation by chest x-ray films. The chest computed tomography scan is highly sensitive in identifying pulmonary contusion and may help predict the need for mechanical ventilation. Respiratory distress is common after lung trauma, with hypoxemia and hypercarbia greatest at about 72 hours. Although management of patients with pulmonary contusion is supportive, pneumonia and adult respiratory distress syndrome with long-term disability occur frequently.

Adult↗
PubMed1997

The current status of haemoglobin-based blood substitutes.

Haemoglobin-based red cell substitutes have recently passed a myriad of safety studies and are now undergoing efficacy evaluation. There are numerous potential benefits with use of these solutions: they are readily available and have a long shelf-life; do not require typing and cross-matching; are free of viral or bacterial contamination; lack the immunosuppressive effects of blood; and have a much lower viscosity than blood. One-third of the 10 million units of blood transfused in the United States each year is utilized in the emergency setting. Therefore, a safe, effective substitute for blood should have significant impact upon the way we resuscitate bleeding patients. In this article, the current status of the various haemoglobin-based red cell substitutes is reviewed.

Blood Substitutes↗
PubMed1997

Resuscitation of pulmonary contusion: hypertonic saline is not beneficial.

We postulated that hypertonic solutions could minimize the accumulation of lung water and subsequent respiratory derangements that occur after pulmonary contusion. Anesthetized pigs underwent contusion of the right chest at baseline and then were hemorrhaged (30 cc/kg) over 20 min. They were resuscitated with either 7.5% NaCl (4 cc/kg) or .9% saline (90 cc/kg) for 20 min and observed for 4 h. Gravimetric lung weights and spiral computed tomography scans were used to quantitate lung water. The hemodynamic response to contusion and hemorrhage was similar in both resuscitation groups. Arterial oxygen tension was not significantly altered by the method of resuscitation and remained close to baseline values for the entirety of the experiment. Static compliance measurements were significantly decreased from baseline in both groups following pulmonary contusion. There were no differences in wet to dry lung weights or computed tomography scan injury volume between groups. We conclude that small volume hypertonic saline resuscitation does not reduce the magnitude of lung injury or provide substantial physiologic benefit over isotonic solutions following pulmonary contusion.

Animals↗
PubMed1996

Do surgeons have a role as infectious disease consultants?

BACKGROUND: Antibiotic drug restriction policies have become widespread in North America hospitals mandating medical infectious disease consultation for use of routine antimicrobial agents. OBJECTIVE: To determine physician and institutional attitudes regarding the credibility of surgeons in the area of infectious disease. DESIGN: A survey of the Surgical Infectious Disease Society (SIS) membership. PARTICIPANTS: Members of the SIS practicing in the United States and Canada (n = 464) were sent a simple opinion poll regarding surgical infectious disease specialists. After receiving the survey, the SIS members were given approximately 4 weeks to anonymously complete the questionnaire and return it to our office. RESULTS: Responses were received from 198 SIS members (43%). Most were from large (> 400 bed) institutions (63%), and the majority of them were from university centers (76%). Predictably, 86% of the respondents were in full-time academic practice. Some SIS respondents (21%) had undergone special training in infectious disease, and of these, 63% actually had completed a formal surgical infectious disease fellowship. Antibiotic restriction policies were nearly universal and required in 87% of institutions. Only 44% of surgeons in these hospitals, however, were privileged to release antibiotic drugs. Medical infectious disease physicians recognized surgical expertise in infectious disease in few instances (32%). The great majority of responding SIS members (81%) believed that an examination or certification in infectious disease for surgeons was not warranted. CONCLUSIONS: Antibiotic drug restriction is prevalent in North America, and medical infectious disease specialists do not generally recognize surgical expertise in the area of infectious disease. Despite this environment, responding SIS members believe that special credentialing of surgeons in the area of infectious disease is unnecessary.

Communicable Diseases↗
PubMed1996

Characteristics of the propagating pressure wave in the esophagus.

Understanding the relationships of intraluminal manometric events to bolus transit through the esophagus has been limited by conventional manometric analysis methods. We reconstructed pressure events in the axial direction in order (1) to describe the peristaltic pressure wave as it propagates through the esophagus in the direction of the bolus and (2) to determine what sampling interval along the esophageal length is required for accurate representation. Esophageal manometric studies using the stepwise withdrawal method were performed in 10 asymptomatic volunteers. Propagating wave forms were created at 0.2-sec intervals and analyzed in static and dynamic fashion from averaged waves at each 1-3 cm of esophageal length. A distinctive and similar appearance to the propagating wave form, comprised of three sequential but overlapping contraction segments in the esophageal body, was present in nine subjects. The propagating wave decelerated as it approached the second region (smooth-muscle esophagus) and extended over as much as 15.1+/-0.7 cm of esophageal length. No significant differences in wave front propagation, length, or velocity could be determined if the sampling interval increased from 1 to 3 cm of esophageal length, but peak amplitudes were reduced by as much as 14.2%. We conclude that the esophageal pressure wave, when viewed in the direction of bolus transit, is broad and typically comprised of three sequential contraction components. Sampling at >1-cm intervals along the esophageal length significantly alters the wave appearance and may be unsatisfactory in the distal esophagus. Axial transformations of manometric data potentially will provide better information concerning the neuromuscular control of peristalsis and events responsible for bolus movement.

Adult↗
PubMed1996

Sump syndrome complicating Roux-en-Y hepaticojejunostomy: case report and review of the literature.

Sump syndrome is a rare complication of biliary-enteric anastomosis. Classically, the distal bile duct becomes obstructed by gastrointestinal debris after choledochoduodenostomy, resulting in cholangitis or, less commonly pancreatitis. Obstruction of the biliary tree by gastrointestinal contents after Roux-en-Y choledochojejunostomy or hepaticojejunostomy has not been described in the English-language literature. This report details the diagnostic and operative management of the first patient with sump syndrome after hepaticojejunostomy. The presumed pathophysiology was reflux of vegetable matter up the efferent limb, resulting in hepatic duct obstruction and cholangitis. The patient ultimately required complex choledochoscopic drainage of the intrahepatic biliary tree and revision of the previous Roux-en-Y hepaticojejunostomy.

Adult↗
PubMed1996

Enteric absorption of ciprofloxacin during tube feeding in the critically ill.

To determine the pharmacokinetic properties of ciprofloxacin in the critically ill, we studied seven mechanically ventilated patients with pneumonia during enteral feedings. Subjects received ciprofloxacin 750 mg every 12 h via nasogastric tube and serial serum drug concentrations were measured after the first and fourth dose. After the initial dose, the maximum serum concentration ranged from 1.24-3.06 mg/L, and the area under the time curve from 0-12 h ranged from 3.2-19.65 mg.h/L. Similar levels were noted after dose four. Gastrointestinal absorption of ciprofloxacin in tube fed critically ill patients was decreased, but well above MIC values for many pathogenic bacteria.

APACHE↗
PubMed1996

Nonoperative management of a splenic tear in a Jehovah's Witness with hemophilia.

Splenic laceration, the most common visceral lesion following blunt abdominal trauma, can be treated in a nonoperative fashion in only a select group of stable patients with minimal injury. We report a unique case of life-threatening splenic trauma in a Jehovah's Witness with hemophilia that was successfully managed without surgery.

Adolescent↗
PubMed1996

Experimental pulmonary contusion: review of the literature and description of a new porcine model.

In the setting of pulmonary contusion, massive crystalloid resuscitation of hemorrhagic shock may promote increased lung water leading to stiffer lungs and ultimately culminating in adult respiratory distress syndrome. The emergence of fluids that enable the clinician to resuscitate the bleeding trauma victim by using minimal fluid volumes offers new avenues of investigation for resuscitation of traumatic lung injury. Unfortunately, there has been very little experimental work in the area of pulmonary contusion in the past 15 years. We describe a new porcine model for experimental traumatic lung injury that appears to replicate the clinical scenario.

Animals↗
PubMed1996

Doppler color flow imaging surveillance of deep vein thrombosis in high-risk trauma patients.

To determine the prevalence of upper and lower extremity deep vein thrombosis in high-risk trauma patients, 136 consecutive high-risk trauma patients were prospectively evaluated with weekly Doppler color flow imaging. Incomplete compressibility and visualized intraluminal thrombus were considered diagnostic of deep vein thrombosis. Pulmonary embolus was documented by pulmonary arteriography. Deep vein thrombosis occurred at 27 non-contiguous sites in 19 patients (14%). Eight of 27 cases of deep vein thrombosis (30%) involved the upper extremity and 19 (70%) occurred in the lower extremity. Twenty-one of 27 deep vein thromboses (78%) were partially occlusive, whereas six (22%) were occlusive. Pulmonary embolus was documented in three patients (2.2%). Doppler color flow imaging detected occult deep vein thrombosis in 14% of high-risk trauma patients (30% occurring in the upper extremity).

Adolescent↗