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Biomedical subjects

S R Shackford

Publications and source records attributed to S R Shackford.

At least 91 records · Page 5Linked to original sources
PubMed1992

The clinical utility of computed tomographic scanning and neurologic examination in the management of patients with minor head injuries.

The evaluation and management of patients with minor head injury (MHI: history of loss of consciousness or posttraumatic amnesia and a GCS score greater than 12) remain controversial. Recommendations vary from routine admission without computed tomographic (CT) scanning to mandatory CT scanning and admission to CT scanning without admission for selected patients. Previous reports examining this issue have included patients with associated non-CNS injuries who confound the interpretation of the data and affect outcome. We hypothesized that patients with MHI and no other reason for admission with normal neurologic examinations and normal CT scans would have a negligible risk of neurologic deterioration requiring surgical intervention. To validate this hypothesis we studied 2766 patients with an isolated MHI admitted to seven trauma centers between January 1, 1988, and December 31, 1991. There were 1898 male patients and 868 female patients; injury was blunt in 99%. A neurologic examination and a CT scan were performed on 2166 patients; 933 patients had normal neurologic examinations and normal CT scans and none required craniotomy; 1170 patients had normal CT scans and none required craniotomy; 2112 patients had normal neurologic examinations and 59 required craniotomy. The sensitivity of the CT scan was 100%, with positive predictive value of 10%, negative predictive value of 100%, and specificity of 51%. The use of CT alone as a diagnostic modality would have saved 3924 hospital days, including 814 ICU days, and $1,509,012 in hospital charges. Based on these data, we believe that CT scanning is essential in the management of patients with MHI and that if the neurologic examination is normal and the scan is negative patients can be safely discharged from the emergency room.

Adolescent↗
PubMed1992

The deleterious effects of intraoperative hypotension on outcome in patients with severe head injuries.

Prehospital or admission hypotension doubles the mortality for patients with severe head injury (SHI = Glasgow Coma Scale score less than or equal to 8). To our knowledge no study to date has determined the effects of intraoperative hypotension [IH: systolic blood pressure (SBP) less than 90 mm Hg] on outcome in patients with SHI. This study examined 53 patients who had SHI and required early surgical intervention (surgery within 72 hours of injury). All patients were initially normotensive on arrival. There were 17 patients (32%) who developed IH and 36 (68%) who remained normotensive throughout surgery. The mortality rate was 82% in the IH group and 25% in the normotensive group (p less than 0.001). The duration of IH was inversely correlated with Glasgow Outcome Scale using linear regression (R = -0.30; p = 0.02). Despite vigorous fluid resuscitation in the IH group, additional pharmacologic support was used in only 32%. These data suggest that IH is not uncommon after SHI (32%) and that it does have a significant effect on patient outcome.

Adult↗
PubMed1992

An analysis of the relationship between fluid and sodium administration and intracranial pressure after head injury.

Severe head injury is the leading cause of traumatic death. When a severe head injury is combined with hypotension the mortality doubles. The use of asanguineous salt solutions to maintain blood pressure, however, may contribute to cerebral swelling and intracranial hypertension. For this reason, restrictions of fluids (FLD) and sodium (Na) have been advocated. To our knowledge, however, there are no clinical data to support this recommendation. We hypothesized that in adult patients sustaining severe head injuries (Glasgow Coma Scale score less than or equal to 8) with or without associated injuries: (1) FLD balance and total Na administered during the initial 72 hours of hospital admission are positively and significantly correlated with each other, and (2) total FLD, FLD balance, and total Na administration during the initial 72 hours are significantly and positively correlated with changes in ICP and adverse outcome. We retrospectively studied 40 adult trauma patients with severe head injuries. We found a significant correlation between total Na and FLD balance (R2 = 0.54; p less than 0.05). However, we found no significant correlation between total FLD and maximum ICP (R2 = 0.081), ICP score (R2 = 0.01), or outcome (R2 = 0.066), no significant correlation between FLD balance and maximum ICP (R2 = 0.000), ICP score (R2 = 0.000), or outcome (R2 = 0.01), and no significant correlation between total Na and maximum ICP (R2 = 0.000), ICP score (R2 = 0.001), or outcome (R2 = 0.02). We conclude that Na and FLD administration are not independent determinants of ICP during the initial 72 hours after brain injury.

Adolescent↗
PubMed1992

Intravenous fluid tonicity: effect on intracranial pressure, cerebral blood flow, and cerebral oxygen delivery in focal brain injury.

An investigation into the role of intravenous fluid tonicity in determining intracranial pressure (ICP) after brain injury is described. The authors compare the results of infusion of a hypotonic fluid (Ringer's lactate, 270 mOsm/liter) to those of a hypertonic fluid (hypertonic sodium lactate, 500 mOsm/liter) in a porcine model of focal cryogenic brain injury. Hemodynamic parameters (ICP, regional cerebral blood flow (CBF), and oxygen delivery) and serum osmolarity were measured every 3 hours for 24 hours after injury. At sacrifice, the water content of the lesioned and nonlesioned cortex was determined by specific gravity. The cryogenic injury produced a significant increase in ICP and a significant decrease in CBF in all experimental groups. Maintenance infusion of hypertonic sodium lactate for 24 hours resulted in significantly lower ICP, higher CBF and oxygen delivery, and higher serum osmolarity than Ringer's lactate infusion. Cortical water content in the area of the lesion was similar in both groups, but in the uninjured hemisphere it was significantly lower in the hypertonic group. These data suggest that hypertonic maintenance fluid improves intracranial compliance by dehydrating uninjured cortex. Improved CBF in the hypertonic group may be due to dehydration of cerebrovascular endothelium and erythrocytes. By reducing ICP and improving CBF, hypertonic fluid administration may thus reduce secondary brain injury after head trauma.

Animals↗
PubMed1991

A prospective, randomized comparison of computed tomography with conventional diagnostic methods in the evaluation of penetrating injuries to the back and flank.

We prospectively compared computed tomography with conventional diagnostic methods in the evaluation of penetrating injuries to the back and flank in 85 patients. Immediate laparotomy was performed in 24 patients because of physical findings, and these patients were not randomized. Nine unnecessary operations were performed in this group, and these nine patients had significantly higher hospital costs than patients in either randomized group. In the randomized patients, there were only three true-positive and three false-positive findings. Both computed tomographic evaluation (31 patients) and conventional evaluation (30 patients) were highly accurate and specific for injuries that required operation. Evaluation with computed tomography required a longer time to make a hospital disposition but required fewer diagnostic tests. Computed tomography can be useful in the assessment of penetrating injuries to the back and flank.

Abdominal Injuries↗
PubMed1991

A comparison of hypertonic to isotonic fluid in the resuscitation of brain injury and hemorrhagic shock.

We studied the early and late effects of hypertonic resuscitation (HR) on the injured brain using a porcine model of hemorrhagic shock and focal cryogenic brain injury. After shock, swine were randomly assigned to receive a bolus (4 cc/kg) of either Ringers lactate (RL) or 7.5% hypertonic saline in 6% Dextran 70, followed by either RL or hypertonic sodium lactate to restore mean arterial pressure to baseline. All animals were studied for 24 hr after the start of resuscitation. Bolus HR improved cerebral blood flow (CBF) with a lower intracranial pressure (ICP) than RL. Continued hypertonic resuscitation prolonged the period of improved CBF and low ICP. At 24 hr CBF had deteriorated in the region of injury in all study groups and in the uninjured hemisphere in swine receiving RL. These data suggest that rapid resuscitation without increasing ICP for up to 6 hr as seen with hypertonic fluid could conceivably allow adequate time for surgical evacuation of mass lesions and effectively prevent secondary brain injury. This work underscores the importance of prolonged periods of study when evaluating brain resuscitation from traumatic shock.

Animals↗
PubMed1991

Organ procurement in patients with fatal head injuries. The fate of the potential donor.

A 46-month, retrospective review of all victims of fatal head injury at a level 1 trauma center was undertaken to estimate donor organ availability, determine causes of procurement failure, and analyze the functional results of organs transplanted from this group of donors. Causes of procurement failure in 126 patients who died principally from their head injuries included failure of initial resuscitation (14%), ineligibility (28%), failure of physiologic support (14%), and denial of consent (20%). Of 73 eligible donors, 29 (41%) were able to donate one or more vascular organs (heart, liver, kidney). In only one instance was an eligible donor not appropriately identified as such. Failure of physiologic support to prevent early death (25%), and denial of consent (34%) were found to be the two major, potentially remediable causes of procurement failure in this series. Based on this data, an estimated 29 patients/million population/year will survive initially and meet all eligibility requirements for organ donation. Data on 47 kidneys transplanted from the donor group demonstrated a 77% overall graft survival rate at a follow-up period averaging 23 months. Prolonged donor hypotension, but not the use of high-dose vasopressors, adversely affected allograft survival. The current limitations of organ procurement in victims of fatal head injury stem from a limited ability to maintain cardiopulmonary function long enough for the procurement process to be completed and a high overall rate (46%) of denial of consent for organ harvest by next of kin.

Brain Death↗
PubMed1991

The significance of critical care errors in causing preventable death in trauma patients in a trauma system.

The regionalization of trauma care has led to a decrease in preventable death after injury. This decrease has been attributed to earlier resuscitation and surgical intervention. Little emphasis, however, has focused on the critical care phase of trauma patient management. This study was undertaken to determine the significance of critical care errors (CCEs) on preventable mortality and morbidity in a regionalized system of trauma care. The records of 12,910 trauma patients admitted to six trauma centers over a three-year period were reviewed. The cause and preventability of death was determined by a panel of trauma experts. Critical care errors occurred in 151 (23%) of all patients with errors occurring during any phase of care. The CCEs were identified in 38 of 125 (30%) deaths of patients with errors in some phase of care. The CCEs were implicated as the cause of death in 30 (48%) of the 62 preventable deaths. The proportion of preventable deaths attributable to CCEs was higher than the proportion of preventable death attributable to errors in the resuscitative and operative phases of care (p less than 0.001, chi-square). These data indicate that CCEs significantly contribute to preventable mortality and morbidity in trauma patients. It is imperative that physicians caring for trauma patients possess expertise in the critical care management of injured patients.

Cause of Death↗
PubMed1991

Acute posttraumatic renal failure: a multicenter perspective.

UNLABELLED: Acute renal failure (ARF) following trauma is rare. Historically, ARF has been associated with a high mortality rate. To investigate this entity we conducted a retrospective review of 72,757 admissions treated at nine regional trauma centers over a 5-year period. Seventy-eight patients (0.098%) developed acute renal failure requiring hemodialysis. Detailed demographic, clinical, and outcome data were collected. Patients with pre-existing medical conditions (group I) had a 70% increase in mortality over those without pre-existing conditions (p less than 0.004). Twenty-four patients (31%) developed ARF less than 6 days after injury (group II). The remainder (group III) developed late renal failure (mean time to first dialysis, 23 days). The predominant cause of death was multiple organ failure (82%). There were no differences in mortality because of multiple organ failure among the three groups of patients. Of the 33 survivors, six (18%) were discharged with renal insufficiency, three (9%) were discharged on dialysis, 23 (70%) were discharged home or to rehabilitation, and 27 (82%) had no significant evidence of renal insufficiency. CONCLUSION: Posttraumatic renal failure requiring hemodialysis is rare (incidence, 107 per 100,000 trauma center admissions), but the mortality rate remains high (57%). Two thirds of the cases of posttraumatic renal failure develop late and are secondary to multiple organ failure; one third of the cases of posttraumatic renal failure develop early and may result from inadequate resuscitation.

Acute Kidney Injury↗
PubMed1991

Distal pancreatectomy for trauma: a multicenter experience.

During a 5-year period, 74 patients with pancreatic injuries were managed by distal pancreatic resection at nine referral trauma centers. Patient ages ranged from 4 to 72 years. Injury mechanism was blunt trauma in 34 (46%) patients, gunshot wound in 27 (36%), stab wound in 11 (15%), and shotgun blast in two (3%). There were 19 class II, 50 class III, and 5 class IV pancreatic injuries. The resection comprised up to 33% of the pancreas in 21 (28%) patients, from 34% to 66% in 45 (61%), and greater than 67% in eight (11%). The pancreatic resection margin was closed with staples in 44 (59%), silk sutures in 20 (27%), and polypropylene sutures in eight (11%). Of 32 patients in whom the spleen was uninjured, the spleen was left intact in 17 (53%). There were nine (12%) deaths. The cause of death was irreversible shock in three patients, multiple organ failure in five, and severe head injury in one. Pancreas-related complications occurred in 32 (45%) of 71 patients who survived the initial operation. Intra-abdominal abscess developed in 24 patients; 11 were managed by percutaneous drainage alone. Pancreatic fistula developed in 10 patients; eight closed spontaneously from 6 to 54 days. Other pancreas-related morbidity included pancreatitis (6), pseudocyst (2), and hemorrhage (2). Exocrine insufficiency was not evident in any patient and diet-controlled hyperglycemia occurred in one individual following 80% pancreatic resection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Hypertonic fluid resuscitation improves cerebral oxygen delivery and reduces intracranial pressure after hemorrhagic shock.

Prospective clinical studies have shown that hypotension from hemorrhage contributes to increased morbidity and mortality in patients with traumatic brain injury. It is implied that poorer outcome is the result of secondary brain injury from impaired cerebral oxygen delivery (cO2del). We studied the early and late effects of hypertonic sodium lactate (HSL: 500 mOsm/L) resuscitation on mean arterial pressure (MAP), cardiac output (CO), systemic oxygen delivery (sO2del), cerebral perfusion pressure (CPP), intracranial pressure (ICP), cO2del, cerebral blood flow (CBF), serum osmolality, and cortical water content (CWC) in a porcine model of hemorrhagic shock. Swine were randomized to receive a bolus (4 mL/kg) of either lactated Ringer's solution (LR: 274 mOsm/L) or HSL after shock, followed by either LR or HSL to return MAP to baseline levels. Shed blood was returned 1 hour after resuscitation, and all animals were studied for 24 hours. Control animals were instrumented only. The HSL resuscitation significantly increased cO2del and CBF for 24 hours postresuscitation when compared with LR. The ICP in the HSL-treated animals was significantly lower throughout the postresuscitation phase when compared with the LR-treated animals (p less than 0.05). The CWC was significantly lower in the HSL-treated animals (p less than 0.05). We attribute these effects to hypertonic dehydration of both the brain parenchyma and the cerebrovascular endothelium. These data suggest that by decreasing ICP and improving cO2del after shock, HSL could decrease secondary brain injury when brain injury and shock occur together.

Animals↗
PubMed1991

Base deficit as a sensitive indicator of compensated shock and tissue oxygen utilization.

To determine the relationship of the arterial base deficit (BD) to physiologic indicators of shock and resuscitation--heart rate, mean arterial pressure (MAP), cardiac output (CO), arteriovenous oxygen difference (AVO2), mixed venous oxygen saturation (VSAT) and oxygen delivery to consumption ratio (RATIO)--16 swine were monitored invasively, bled 40 per cent of their calculated blood volume and resuscitated with crystalloid and blood. During hemorrhage, the MAP, CO, VSAT and RATIO decreased and the BD and AVO2 increased. One hour after hemorrhage, but before crystalloid infusion, the MAP, VSAT and RATIO had increased significantly from previous levels and the AVO2 had narrowed significantly, while the BD showed no significant change. All parameters returned to baseline with resuscitation. BD accurately reflected the hemodynamic and tissue perfusion changes associated with hemorrhagic shock and resuscitation in this model. BD can be used as an indicator of the severity of the shock state and the efficacy of resuscitation when invasive monitoring is impractical or not available. BD was more reflective of the true volume deficit during compensated shock than other physiologic variables in this study.

Acid-Base Imbalance↗
PubMed1990

The management of splenic trauma in a trauma system.

Large teaching centers have reported splenic salvage rates of 40% to 50% in adults after splenic trauma. It is unknown whether similar salvage rates can be achieved safely in community trauma centers with a lower volume of patients and less experience. Between August 1984 and August 1988, 117 patients with splenic injury were treated at a level I center and 311 were treated at four level II centers. Splenectomy was performed in 252 patients (59%), splenorrhaphy was performed in 160 patients (37%), and 16 patients (4%) were observed. While the splenic salvage rate was higher at the level I center (50% vs 38%), selective splenorrhaphy was successful in the level II centers where the volume of splenic injury was lower (15 to 25 cases per year).

Adult↗
PubMed1990

Cardiovascular and neurohumoral responses following burn injury.

Cardiovascular and endocrine responses were evaluated in 12 adult patients over a 5-day period following 30% to 66% burn injury. Heart rate, mean arterial pressure, central venous pressure, pulmonary capillary wedge pressure, cardiac output, systemic vascular resistance, and stroke volume were measured. Plasma concentrations of angiotensin II, atrial natriuretic peptide, vasopressin, neuropeptide Y, norepinephrine, and epinephrine were measured. On the day of burn injury, systemic vascular resistance was markedly elevated, and stroke volume and cardiac output were low, but all normalized by day 3, and cardiac output and stroke volume increased by day 5 without significant changes of central venous pressure or pulmonary capillary wedge pressure. Mean arterial pressure and heart rate did not change significantly over the 5-day period. Vasopressin, angiotensin II, neuropeptide Y, norepinephrine, and epinephrine concentrations in plasma were elevated on admission. Vasopressin concentrations were elevated 50 times normal on admission and returned to normal levels by days 4 to 5. Plasma atrial natriuretic peptide concentrations were normal on admission and increased significantly on days 3 to 5. The reciprocal relationship between systemic vascular resistance and cardiac output and between vasopressin and atrial natriuretic peptide correlate with each other and the observed physiologic events that occurred following burn injury and resuscitation. All of these changes in cardiac performance occurred without significant alterations in preload or afterload as measured by central venous pressure, pulmonary capillary wedge pressure, and mean arterial pressure. Increases in plasma levels of atrial natriuretic peptide correlated with the increased stroke volume and cardiac output observed in these patients. The results of this study are consistent with the conclusion that the extreme elevations of plasma vasopressin levels contribute to the vascular complications of increased systemic vascular resistance and decreased cardiac output and contractility seen following burn injury.

Adult↗
PubMed1990

The asymptomatic patient with suspected myocardial contusion.

Diagnostic criteria and guidelines for hospital admission for suspected myocardial contusion (MCC) remain unclear. This study defines and examines the clinical sequelae of patients admitted with a suspicion of MCC. Criteria for observation following isolated, minor blunt chest trauma are suggested. Hospital and trauma registry records of patients admitted over a 33-month period with suspected MCC were reviewed. Conventional evaluation criteria, cardiac-related complications, and associated injuries were analyzed for 524 patients. Twenty-eight cardiac-related complications occurred in 27 of 524 patients (5%). These complications included 23 dysrhythmias, 3 infarctions, and 2 pericardial effusions. There were 23 patients with abnormal admission electrocardiograms and 4 with normal ones. Of the latter, one patient developed dysrhythmia 4 hours after admission, and three had other major multi-system injuries requiring admission to the intensive care unit. The overall incidence of cardiac-related complications in minimally injured patients was 0.1%. There were no complications in patients with isolated chest wall contusions, a normal admission electrocardiogram, and a normal rhythm at 4 hours. There was no significant association between creatine phosphokinase isoenzymes or echocardiogram and cardiac-related complications. The complete absence of significant cardiac sequelae in patients with isolated chest wall contusion, normal admission and 4-hour electrocardiograms, and no other associated major injuries suggests that these patients need not be admitted.

Adult↗