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Biomedical subjects

M L Hawkins

Publications and source records attributed to M L Hawkins.

At least 19 recordsLinked to original sources

Recurrent asystole resulting from high cervical spinal cord injuries.

Cervical spinal cord injury is a highly morbid condition frequently associated with cardiovascular instability. This instability may include bradyarrhythmias, as well as hypotension, and usually resolves in a relatively short time. However, over a 3-year period (January 2003-December, 2005), 5 of 30 patients with complete cervical spinal cord injuries seen at our Level I trauma center required placement of permanent cardiac pacemakers for recurrent bradycardia/asystolic events. Strong consideration for pacemaker placement should be given for those spinal cord-injured patients with symptomatic bradyarrhythmic events still occurring 2 weeks after injury.

Adult↗

Impact of length of stay on functional outcomes of TBI patients.

The purpose of this study was to compare the functional outcomes of two groups of patients with traumatic brain injury (TBI) with attention to the impact of reduced length of stay (LOS) in the trauma center (TC) and rehabilitation hospital (RH). From 1991 to 1994, 55 patients, Group 1, with serious TBI (Abbreviated Injury Scale score > or = 3) were admitted to a level 1 TC and subsequently transferred to a comprehensive inpatient RH. These results have been previously published. From 1996 to 2002, 64 similarly injured patients, Group 2, received inpatient care at the same TC and RH. These patients had a marked decrease in length of stay. Functional Independence Measures (FIM) were obtained at admission (Adm), discharge (D/C), and at 1 year follow-up for both groups. The average length of stay at the TC dropped from 36 days in Group 1 to 26 days in Group 2. In addition, the average length of stay at the RH dropped from 46 days (Group 1) to 25 days (Group 2); overall, an average reduction of 31 days of inpatient care. Group 2 had significantly lower FIM scores at the time of RH discharge for self-care, locomotion, and mobility compared to Group 1. At the 1 year follow-up, however, there were no significant differences between Groups 1 and 2 in these FIM scores. FIM scores at 1 year were higher in Group 2 for communication (90% vs 71%) and social cognition (77% vs 49%) compared to Group 1. Over one-fourth of each group returned to work by the 1 year follow-up. Socially disruptive behavior occurred at least weekly in 28 per cent (Group 1) and 23 per cent (Group 2) of patients. The outcome for serious TBI is better than generally perceived. Reduction of inpatient LOS did not adversely affect the ultimate functional outcome. The decreased LOS placed a greater demand on outpatient rehabilitative services as well as a greater burden on the family of the brain-injured patient.

Adolescent↗

Interleukin-1beta and rhinovirus sensitize adenylyl cyclase in human airway smooth-muscle cells.

Rhinovirus (RV) is a major cause of wheezing in asthmatics and has been reported to cause beta2 adrenergic receptor hyporesponsiveness in human airway smooth muscle (HASM) via cellular secretion of interleukin (IL)-1beta. We studied the effects of IL-1beta and RV on cyclic adenosine monophosphate (cAMP) production in HASM cells. Chronic incubation with IL-1beta or RV caused a significant increase (approximately 3- and approximately 2-fold, respectively) in forskolin (FSK)-stimulated cAMP production, suggesting a sensitization of adenylyl cyclase (AC). The observed augmentation of FSK-stimulated cAMP formation by IL-1beta was completely abrogated by pretreatment with an IL-1 receptor antagonist or cycloheximide, demonstrating that the effect is mediated via the IL-1 receptor 1 (IL-1R1) and that de novo protein synthesis is required. In contrast, RV-induced AC sensitization was not mediated via the IL-1R1 but was observed to be protein kinase C-dependent. We suggest that the sensitization of AC observed after exposure to IL-1beta or RV infection is a cellular defense mechanism to promote pathways that induce relaxation in the inflamed airway.

Adenylate Cyclase Toxin↗

Nonoperative management of liver and/or splenic injuries: effect on resident surgical experience.

Changes in the management of trauma over the past few years are significantly affecting postgraduate surgical education, with the lack of operative trauma experience being a major concern in some programs. This problem is accentuated in residency programs that obtain their trauma caseload primarily from blunt injury. Our experience over the past 6 years confirms that the growing trend toward nonoperative management of blunt liver and spleen injuries in adults is likely to exacerbate this problem. Blunt trauma admissions to our Level I trauma center increased from 2888 from 1991 through 1993 (group A) to 3587 from 1994 through 1996 (group B). Liver and/or splenic injuries occurred with equal frequency in both groups. Whereas diagnostic peritoneal lavage was used in 26 per cent of group A, its use dropped to 2 per cent in group B as abdominal computerized tomography was used more frequently to evaluate these patients. Nonoperative management increased from 10 per cent of group A to 54 per cent of group B. As a result, therapeutic laparotomies dropped from 85 in group A (58% of patients with liver/splenic injuries) to 74 (35%) in group B and nontherapeutic laparotomies from 48 (33%) to 23 (11%). While the evolution in the management of blunt liver and splenic injuries has resulted in the avoidance of nontherapeutic laparotomies, the operative caseload available to surgical housestaff has been adversely affected. Although the Residency Review Committee has stressed the importance of the critical care management of these patients, the criteria used to evaluate the number of trauma cases in postgraduate surgical education may need to be revised.

Abdominal Injuries↗

Pharmacokinetics of reconstituted human high-density lipoprotein in pigs after hemorrhagic shock with resuscitation.

OBJECTIVES: Reconstituted human high-density lipoprotein (HDL) can inhibit lipopolysaccharide effects in vivo. The major objectives of this study were to characterize the pharmacokinetics of reconstituted HDL in a stressed large-animal model and to provide preclinical tolerance information in support of use of reconstituted HDL in humans. DESIGN: A randomized, blinded, placebo-controlled trial where each animal received either reconstituted human HDL at a dose of 100 mg/kg (apolipoprotein A-I) or placebo, immediately after hemorrhagic shock and resuscitation. SETTING: Animal laboratory. SUBJECTS: Twelve immature female swine (18 to 25 kg) were studied. INTERVENTIONS: Six to 8 days before shock and study drug administration, animals were anesthesized and catheters were placed in the external jugular vein and abdominal aorta. These catheters were secured to the dorsal surface. On the day of shock, the animals were sedated (alpha-chloralose) and 50 mL/kg of arterial blood was removed over 0.5 hr. One half hour after blood removal, shed blood was infused, which was immediately followed by study drug (reconstituted HDL or placebo), and then by 1 L of lactated Ringer's solution. MEASUREMENTS AND MAIN RESULTS: Physiologic (arterial blood pressure, heart rate, respiratory rate) and laboratory (serum chemistries, hematologic and coagulation studies, and blood gases) measurements were determined intermittently for 96 hrs after the induction of shock. Blood was collected intermittently for 48 hrs after shock for assay of apolipoprotein A-I and phosphatidylcholine in plasma. Reconstituted HDL was well tolerated and did not appear to alter the physiologic responses to shock and resuscitation. HDL transient increase in aspartate aminotransferase concentration was noted in the reconstituted group but this increase normalized by 24 hrs after drug administration. Mean apolipoprotein A-I pharmacokinetic parameters were as follows: half-life 24.5+/-5.3 (SD) hrs; clearance 41.9+/-10 mL/hr; and volume of distribution 1.39+/-0.08 L. The apparent mean half-life of phosphatidylcholine was 5.4+/-0.8 hrs. CONCLUSIONS: Reconstituted human HDL was well tolerated in animals that had undergone hemorrhagic shock with resuscitation. The apolipoprotein component of reconstituted HDL had a relatively long half-life, with distribution limited to the vascular space. These findings support the investigational use of this product in humans.

Analysis of Variance↗

Serious traumatic brain injury: an evaluation of functional outcomes.

OBJECTIVES: Evaluate independent living, productivity, and social outcomes of patients with serious traumatic brain injury (TBI) after inpatient rehabilitation. METHODS: Fifty-five adults with serious TBI (Abbreviated Injury Scale score > or = 3) were admitted to a Level I trauma center and subsequently transferred to a comprehensive inpatient rehabilitation hospital (Walton Rehabilitation Hospital). Functional Independence Measures were obtained at admission (Adm), discharge (D/C), and at 3- (n = 52) and 1-year (n = 51) follow-up. RESULTS: At 1 year, 90% of the patients were living at home. Eight (16%) required full-time supervision, while 41 (82%) were independent of supervision throughout most of the day. Thirteen (25%) patients had returned to work, eight full time and five with reduced responsibility and fewer hours than before injury. Nineteen shared household duties, while eight (16%) had primary responsibility. Fourteen (27%) patients demonstrated socially inappropriate or disruptive behavior at least weekly. [table: see text] CONCLUSION: Although cognitive skills were diminished for the majority of patients, many achieved a substantial reduction in disability within 18 months after TBI.

Activities of Daily Living↗

Emergency cricothyrotomy: a reassessment.

The Medical College of Georgia Level I Trauma Center admitted 5603 adult trauma patients from January 1, 1989 through June 30, 1993. Cricothyrotomy was required in 66 of 525 patients who required emergency airway control but could not be intubated nonsurgically in an expeditious manner. There were three major complications (thyroid cartilage laceration, significant hemorrhage, and failure to obtain a surgical airway) involving two patients, but each resolved without sequelae. Twenty-six patients with cricothyrotomy survived their hospital course, of which seven had decannulation of the cricothyrotomy without further airway procedures, and 19 had conversion to tracheostomy. No patient had clinically significant morbidity from the cricothyrotomy, whether with or without a subsequent tracheostomy. Surgical cricothyrotomy remains an important technique with low morbidity for selected trauma victims needing emergency airway control.

Adult↗

Reconstituted high density lipoprotein inhibits physiologic and tumor necrosis factor alpha responses to lipopolysaccharide in rabbits.

OBJECTIVE: To determine the effect of reconstituted human high density lipoprotein (rHDL) on physiologic and cytokine responses to infusion of lipopolysaccharide. DESIGN: A blinded, randomized trial of three preparations of a purified human rHDL with apolipoprotein A-I-phosphatidyl choline-cholesterol molar ratios of 1:100:10, 1:150:10, and 1:200:0 and placebo in a rabbit lipopolysaccharide intravenous infusion model. INTERVENTIONS: Groups of six New Zealand white rabbits received either placebo or one of the three human rHDL preparations above as a single, 75-mg/kg (apolipoprotein A-I equivalent) dose intravenously over 10 minutes ending 5 minutes before the start of a 3-hour infusion of lipopolysaccharide. MAIN OUTCOME MEASURES: Mean arterial pressure, base excess, and plasma tumor necrosis factor alpha (TNF-alpha) production were determined. RESULTS: The human rHDL suppressed TNF-alpha production with the products having the highest fraction of phosphatidyl choline producing the greatest suppression of TNF-alpha production. The human rHDL 1:200:0 group maintained a low, near-baseline TNF-alpha concentration and minimal decline in mean arterial pressure and base excess throughout the lipopolysaccharide infusion in contrast to the placebo group. CONCLUSION: Reconstituted human high density lipoprotein appears to be useful in inhibiting the physiologic effects and cytokine release associated with endotoxemia and may provide adjunctive treatment for patients with gram-negative sepsis.

Acidosis↗

Physiologic amputation prevents myoglobinuria from lower extremity myonecrosis.

Myoglobinuria secondary to myonecrosis is a proven cause of renal failure, especially in critically ill patients. Physiologic amputation or cryoamputation has been used at our institution for the past two decades as a safe and effective treatment for lower extremity infection, intractable rest pain, and irreversible myonecrosis. We retrospectively studied five critically ill patients with myonecrosis of lower extremities associated with myoglobinuria. The etiology of myonecrosis included preexisting peripheral vascular disease or crush injury to the lower extremities. It was determined that all five patients were too ill to undergo emergency amputation. Myoglobinuria was documented in all five patients and cleared within 24 hours of physiologic amputation in four patients. All five patients had elevated creatine phosphokinase levels (mean 20,270 mU/mL, range 12,090 to 43,164 mU/mL) that significantly decreased within 48 hours of physiologic amputation (mean 6,488 mU/mL, range 2,250 to 13,580 mU/mL). Mechanical ventilation and cardiovascular support were required in four patients. All patients had transient episodes of renal insufficiency with two progressing to anuric renal failure and requiring dialysis. One patient's renal failure resolved after 56 days, but the other patient died of a cerebrovascular accident 22 days after initiation of physiologic amputation. The mean duration of physiologic amputation was 15.6 days (range 5 to 32 days) with no significant complication due to physiologic amputation. All five patients had surgical amputation successfully. Three patients survived. The two deaths in the study were due to a cerebrovascular accident in one patient and a cardiopulmonary arrest in another. Physiologic amputation is a treatment option that halts myonecrosis, prevents myoglobinuria, and lessens the risk of associated acute renal failure. Physiologic amputation may be appropriately used in patients with myoglobinuria due to extremity myonecrosis who are deemed too critically ill to survive emergency amputation.

Acute Kidney Injury↗

Management of post-traumatic acute renal failure with peritoneal dialysis.

To evaluate the efficacy of peritoneal dialysis (PD) in the management of post-traumatic renal failure, the authors reviewed the courses of five critically injured patients treated with PD over an 18-month period. Each patient had a double-cuffed PD catheter inserted through a subcutaneous tunnel with PD initiated within 48 hours. The dialysis prescription was individualized for each patient with frequent exchanges performed using either a manual manifold system or a continuous cycling machine. Three of the five patients survived and none of the survivors required dialytic therapy at discharge. Duration of PD ranged from 10 to 57 days. Three patients required intermittent hemodialysis (HD) due to progressive azotemia and hyperkalemia. Two patients developed bacterial peritonitis and three patients developed hyperglycemia with PD continuing without interruption in each patient. When compared to HD, PD offers the advantages of better hemodynamic tolerance, no anticoagulation, no vascular access, and a reduced personnel requirement if continuous cyclic PD is used.

Academic Medical Centers↗

Current role of cryoamputation.

Cryoamputation or physiologic amputation has been used at our institution for more than 30 years. From 1971 through 1989, 891 major lower extremity amputations were performed in 750 patients. With the use of dry ice or mechanical refrigeration, 320 (36%) physiologic amputations were performed in 292 patients. After physiologic amputation, the initially elevated white blood cell count and temperature decreased. Complications of physiologic amputation were unusual; 3% of patients developed minor freezing above the tourniquet, which did not alter the amputation level, while 1% had purulence at the level of surgical amputation that required delayed stump closure. The overall operative mortality rate in patients who underwent physiologic amputation was 11%, which was equivalent to the rate in patients undergoing primary amputation. Revision was required in 9% of amputations after preliminary physiologic amputation compared with 17% of primary amputations. Physiologic amputation is a simple technique, controls local infection, avoids emergency surgery, and allows for medical stabilization prior to surgery. Amputation revision after physiologic amputation is required less often than after primary amputation, while the mortality rate is comparable to that of patients undergoing primary amputation.

Adolescent↗

Bilaminate synthetic dressing for partial thickness burns. Lack of cost reduction for inpatient care.

Forty-nine cases of second degree burns initially treated as inpatients from April 1984 through December 1987 are reviewed. Thirty-four patients were treated with bilaminate synthetic dressing (Biobrane) application, while 15 were treated with a topical antimicrobial, usually silver sulfadiazine. The burns ranged from 1 to 25 per cent total body surface area and were comparable in both groups. The mean age in each group was 30 years. Thirty patients were successfully treated with Biobrane, and their average hospital stay was 9.1 +/- 5.4 days compared with 9.2 +/- 8.6 days for the topically treated group. The mean hospital cost for dressings and supplies for the Biobrane group was $360 +/- $90 compared with $310 +/- $190 for the topical group. Four patients (12%) required Biobrane removal during their hospitalization, one due to increasing burn depth and three due to purulent fluid collections beneath the Biobrane. These burns were subsequently treated with topical antimicrobial agents and healed primarily. The mean total hospital stay for this group was 18.0 +/- 11.9 days with the costs being much higher secondary to the initial cost of the Biobrane, the costs associated with topical antibiotic therapy, and extended hospital stay. Although there was a decrease in nursing time and a subjective decrease in patient discomfort associated with using synthetic dressing, no benefit was found in either decreasing hospital stay or total cost of hospitalization and supplies used for inpatients treated at this institution.

Adult↗

Deer stands: a significant cause of injury and mortality.

Deer hunting is a popular recreational activity in the United States. Although the risks associated with firearms are well known, the hazards related to deer stands are not widely appreciated. From September 1982 through December 1989, there were 19 patients admitted to the Medical College of Georgia Hospital and Clinics for injuries sustained from falls related to deer stands. One death occurred, and six of the 18 survivors remain paralyzed. Data from 18 of these patients showed that 83% of these falls (15/18) were associated with hunter-constructed stands. Structural failure accounted for 39% (7/18) of the accidents; other causes included carelessness, falling asleep, and medical events. Four of the 19 patients (21%) had elevated blood alcohol levels on admission. Fracture of the spine and long bones accounted for the majority of the injuries, and seven of the 18 survivors (39%) were hospitalized for more than 4 weeks. Eight of the survivors (44%) remain permanently disabled. Deer-stand-related falls may result in significant long-term disability, expensive and lengthy hospitalization, and even death. A preventive approach to these injuries is paramount, and published guidelines for safety while hunting from deer stands should be followed.

Accidental Falls↗

Management of blunt hepatic duct transection by ligation.

We have reported a case of blunt trauma causing major hepatic injury and disruption of the right hepatic duct. The patient was treated with resectional debridement and ligation of the right hepatic duct; he has done well, without jaundice or signs of hepatic dysfunction. We recommend lobar hepatic duct ligation when other more conventional avenues such as primary repair or biliary-enteric anastomosis are precluded by hemodynamic instability or a nonreconstructable duct.

Adult↗

Acute airway management. Role of cricothyroidotomy.

Thirty-four cases of emergency cricothyroidotomy performed formed from September 1984 through January 1988 are reviewed. Thirty-one of the cases were required out of 2,200 acute-trauma patients. The indication for cricothyroidotomy was inability to establish an airway by intubation usually in a situation of possible neck injury or severe facial trauma. Fourteen of the patients died as a result of their injuries, 13 of these in the first several hours after injury. The 20 surviving patients are studied in two groups: eleven patients whose cricothyroidotomy remained in place until decannulation (group I) and nine patients who underwent tracheostomy subsequent to cricothyroidotomy (group II). Clinical follow-up included physical examination in all survivors and endoscopic evaluation in twelve patients. Three minor complications were discovered in each of the two groups and two major complications were noted in group II. The major complications included a case of tracheal stomal stenosis requiring tracheal resection and a case of partially obstructing tracheal granulation tissue requiring endoscopic resection. This study supports the use of emergency cricothyroidotomy in situations in which intubation is not successful or thought to be safe. Data is also presented that suggests that tracheostomy subsequent to emergency cricothyroidotomy does not necessarily reduce airway-related morbidity in these patients.

Airway Obstruction↗

Is diagnostic peritoneal lavage for blunt trauma obsolete?

Diagnostic peritoneal lavage was 97 percent accurate, with a 2 percent false positive rate and a 1 percent false negative rate in this series of 414 patients. The ease, safety, and accuracy of diagnostic peritoneal lavage justify its continued use in evaluating these patients. Recent studies show computerized tomography (CT) can be highly accurate in detecting intra-abdominal injuries after blunt trauma. We reviewed our experience with diagnostic peritoneal lavage (DPL) to evaluate whether the accuracy, safety, speed, and cost justified its continued use. Four hundred fifteen DPLs were performed on 414 patients from February 1, 1983, through December 31, 1987. All DPLs were done by the open technique. The lavage was considered grossly positive if 10 cc gross blood were aspirated. If there were greater than 100,000 red blood cells (RBC)/mm3, greater than 500 white blood cells (WBC)/mm3, elevated amylase or bilirubin, or bacteria or vegetable fibers the lavage was microscopically positive. There were no cases with elevated bilirubin, amylase, or presence of bacteria. All four cases with "rare vegetable fibers" were false positive. Six DPLs were for penetrating trauma to the lower chest or back. There were 291 negative lavages, including five false negatives (1%), and 124 positive DPLs, including seven false positives (2%), resulting in a crude accuracy of 97 percent. Three of the five false negative lavages had a ruptured diaphragm as the only intra-abdominal injury. There was one minor complication. DPL was usually performed in the trauma resuscitation room during the secondary survey. At our institution, the total fees for DPL are +185 less than the fees for CT. DPL is accurate, rapid, safe, and avoids the disruption of patient care that results in the radiology suite. DPL remains our procedure of choice for evaluating blunt abdominal trauma in the adult.

Abdominal Injuries↗