Appropriateness of a 4 mg/kg gentamicin or tobramycin loading dose in post-operative septic shock patients.

OBJECTIVE: To determine the frequency with which early adequate peak serum concentrations (6-12 mg/ litre) can be achieved following a 4 mg/kg loading dose of gentamicin or tobramycin in post-operative septic shock patients. METHOD: Eleven post-operative septic shock patients were grouped into (i) a control group (n=7) who received the conventional gentamicin or tobramycin dosing regimen of 2 mg/kg loading dose followed by a maintenance dose of approximately 1.5mg/kg (peak and trough levels were measured after the third dose), and (ii) a study group (n = 4) who received a tobramycin or gentamicin 4 mg/kg loading dose, followed by 30 min, 3 h and 16 h serum drug level measurements. Pharmacokinetic parameters were calculated using a one-compartmental model. Differences in both groups were determined using Student's t-test. RESULTS: Pharmacokinetic parameters in both groups showed no statistically significant difference. The dose from which peak levels were drawn was significantly higher in the study group (4 mg/kg vs. 1.66 mg/kg; P = 0.001), which also resulted in higher but adequate peak serum concentrations (8.9+/-2.2 vs. 4.8+/-1.8 mg/litre). In the study group, linear regression analysis showed significant relationships between dose and peak concentrations and volume of distribution and peak concentrations (r = 0.96, P= 0.01 and r= -0.96, P= 0.01, respectively). CONCLUSION: One hundred per cent of the post-operative septic shock patients achieved target peak serum concentrations (mean 8.9+/-2.2 mg/litre) following a 4 mg/kg tobramycin or gentamicin loading dose. An expanded Vd (0.46+/-0.13 litres/kg) was also observed.

Aminoglycoside pharmacokinetics in African-Americans with normal renal function.

OBJECTIVE: To compare aminoglycoside pharmacokinetics in African-Americans with normal renal function with published adult population values. DESIGN: An Institutional Review Board approved concurrent study. SETTING: The study was conducted at Howard University Hospital, Washington DC. SUBJECTS: All subjects had serum creatinine levels of 1.5mg/dl or less and were receiving aminoglycoside for suspected or documented Gram-negative infection, had no obvious underlying disease condition that could influence aminoglycoside pharmacokinetics and were aged 18 years or older. MAIN OUTCOME MEASURES: Volume of distribution (Vd), half-life (t1/2), elimination rate constant (Ke) and total body clearance (Cl) were calculated using a one-compartment, open, linear pharmacokinetic model. Using an unpaired Student's t-test, the pharmacokinetic values of our patients were compared with general population values. INTERVENTIONS: Patients receiving aminoglycosides were identified by the pharmacist through the hospital's standard antibiotic order sheet. Twenty-five patients were enrolled after they met the inclusion criteria. Pharmacists made recommendations for dose change as part of standard of care when inappropriate doses were ordered. In collaboration with medical and nursing staff, the amount and time of dose administration, and steady-state peak and trough serum drug levels were stringently measured, documented on a data collection form and used to calculate pharmacokinetic values for our patients. The form was also used to document demographic information. RESULTS: The following values were obtained: Vd 0.27+/-0.15 litres/kg, t(1/2) 1.93+/-1.38h, Ke 0.31+/-0.134/h (gentamicin), Ke 0.22 +/- 0.10/h (tobramycin), Cl 103.95+/-62.98ml/kg/h (gentamicin) and Cl 118.96+/-84.83ml/kg/h (tobramycin). These values are not significantly different from general population values. Following a mean tobramycin or gentamicin dose of 1.32+/-0.32mg/kg ideal body weight (IBW)/ dose or 1.11+/-0.33 mg/kg actual body weight (ABW)/ dose every 8h, patients achieved a mean peak and trough serum drug levels of 6.6+/-3.86mg/litre and 1.03+/-0.68mg/litre, respectively. Wide interpatient pharmacokinetic variability was also observed. CONCLUSIONS: We conclude that aminoglycoside pharmacokinetics in African-Americans seem to be consistent with the published general population values. Thus, initiating aminoglycoside regimens using population dosing guidelines appears to be appropriate. However, due to the observed wide interpatient pharmacokinetic variability, individualized dosing is required with very close monitoring, to avoid or minimize toxicity.

Venous thromboembolism after penetrating chest trauma is not a cause of early death.

BACKGROUND: Venous thromboembolism has been recognized as a potentially life-threatening complication following major thoracic trauma. Little or no attention has been directed at the difference in rates of venous thromboembolism in subjects with penetrating and nonpenetrating chest trauma. METHODS: The reported experience with venous thromboembolism in subjects with chest trauma has not segregated the effect penetrating vs. closed chest trauma. The influence of long-term hospitalization to the formation deep vein thrombosis, pulmonary embolism or subsequent death. The present study evaluated the causes of early death occurring within 96 hours of hospitalization for penetrating chest trauma. The clinical records and autopsy reports of 32 individuals, who died within 96 hours of admission to hospital for penetrating chest trauma, were evaluated for the presence of deep vein thrombosis and pulmonary embolism. RESULTS: All 32 subjects were male with an average age of 31 years. Eighty percent were successfully resuscitated in the emergency room. Forty percent (40%) required an emergency or operating room thoracotomy. The initial revised trauma score (RTS) was below 4 in each case. Thirty-two percent (32%) of the patients died on the fourth day; 48% died between 1 and 3 days of admission and 20% died in the emergency room. None of the patients had any clinical signs or evidence of deep vein thrombosis or pulmonary embolism. Moreover, the autopsy findings were negative for deep vein thrombosis and pulmonary embolism. CONCLUSION: Deep vein thrombosis and pulmonary embolism is rarely a cause of death within the initial 96 hours of hospitalization in individuals sustaining penetrating chest trauma.

Consumer product-related ocular trauma.

Leading causes of consumer product-related ocular trauma have not been well described. To delineate these causes in a nationally representative sample, data collected by the US Consumer Product Safety Commission (USCPSC) were reviewed. Data were obtained from the National Electronic Injury Surveillance System (NEISS), a national probability sample survey conducted by USCPSC that continuously monitors consumer product-related injuries treated in hospital emergency rooms across the United States. These data formulated the product summary report for the calendar year 1991. The sampling frame for the NEISS consisted of hospitals listed on the Center for Health Statistics Master Inventory File stratified geographically by size of hospital and number of emergency-room visits. During the calendar year 1991, there were a nationally estimated 298,852 consumer product-related eye injuries treated in hospital emergency rooms. Appoximately 500 different products were implicated in these injuries, with the leading cause being contact lenses (hard and soft), accounting for an estimated 26,490 emergency-room visits. This is followed by welding equipment (12,771 visits), hair curlers/curling irons (5946 visits), and workshop power grinders (5476 visits). Consumer products account for a sizable number of ocular injuries requiring treatment in hospital emergency rooms. Research on outcomes and prevention strategies of the injuries is warranted.

Retinal hemorrhage secondary airbag-related ocular trauma.

A case is presented in which a driver, who was wearing a three-point restraint system, was involved in a collision that triggered deployment of the vehicle's driver's-side airbag. The victim complained of blurred vision after the crash and on examination was found to have suffered a retinal hemorrhage in his right eye. Since no other cause could be determined, his injury was considered to be a result of contact with the deploying airbag.

Evaluation of massive volume replacement in the penetrating trauma patient.

The records of 163 penetrating trauma patients who required surgery in a 36-month period between 1988 and 1990 were reviewed. Those patients with head trauma were excluded. Thirty patients were identified as having: similar Injury Severity Scores (ISS), received at least 8 L of crystalloid, and received at least 4 units of packed red blood cells during the first 24 hours after admission. There were 22 (73%) survivors and 8 (27%) nonsurvivors. Charts were reviewed for a variety of variables to determine which characteristics distinguished nonsurvivors from survivors. The mean ISS was 30.5 +/- 5.5. As a group, nonsurvivors received more blood transfusions (14.9 +/- 4.9 versus 5.0 +/- 1.14), had longer durations of shock (55.6 +/- 18 minutes versus 19.3 +/- 11.7 minutes), and had lower core body temperatures (92.6 degrees F +/- 2.2 versus 95.1 degrees F +/- 2.4) than survivors. Nonsurvivors also had lower hemoglobin levels (7.84 +/- 1 versus 9.1 +/- 2.3) and platelet counts (134.2 +/- 14.1 versus 188.6 +/- 6.3) than survivors. In addition, nonsurvivors demonstrated greater incidence of three major risk factors than did the survivors: hypothermia (75% versus 41%), acidosis (100% versus 27%), and coagulopathy (62% versus 4.5%). Therapeutic measures to limit these risk factors for increased mortality may maximize the chance of survival in these patients.

Asymptomatic pneumoperitoneum diagnostic and therapeutic dilemma.

The most common cause of pneumoperitoneum is iatrogenic postsurgical free air that enters the abdominal cavity during laparotomy. In these patients, pneumoperitoneum usually resolves within the first week of surgery and laparoscopic procedures. In patients who have not had recent laparotomy or laparoscopy, pneumoperitoneum indicates rupture of an intra-abdominal viscus in about 90 per cent of the time. Perforated gastric and duodenal ulcers account for the greatest number of these cases. The other 10 per cent are due to a variety of nonsurgical causes that can often be treated by supportive and non-operative measures. Lack of clinical awareness about these small but significant subset of patients who present with spontaneous benign pneumoperitoneum is a source of needless laparotomies that can at times lead to serious postoperative complications. Benign pneumoperitoneum can be categorized according to the source of the gas as suggested by Gantt. The thoracic cavity is by far the most common source, followed by the GI and female genital tracts and a host of other miscellaneous causes. We report here six patients who presented to Howard University Hospital with nonsurgical pneumoperitoneum. Four of these patients underwent negative laparotomies and one died postoperatively. The most common causes of benign pneumoperitoneum are discussed and a review of the literature is presented.

Postoperative adult respiratory distress syndrome: the Howard experience.

To describe the natural history of adult respiratory distress syndrome (ARDS), we compared the clinical course of two groups of postoperative critically ill patients who developed respiratory failure requiring prolonged endotracheal intubation (minimum: 4 days). The two groups with ARDS (Group 1) and without ARDS (Group 2) were compared for the following clinical parameters: PO2/FIO2 ratio, cardiac index, pulmonary capillary wedge pressure, systemic and pulmonary vascular resistance, pulmonary compliance, serial chest radiograph findings, presence or absence of sepsis, oxygen transport parameters, morbidity, and mortality. Twenty patients are described over a 9-month period ending in March 1990-10 patients in each group. Characteristic differences between the two groups in terms of oxygen consumption, pulmonary compliance, pulmonary vascular resistance, numbers of organ systems failing, and mortality were noted. Our experience supports the recommendations of early institution of positive and expiratory pressure and optimizing oxygen delivery parameters in the management of ARDS.

Selenium deficiency in long-term total parenteral nutrition.

Although selenium is an essential trace element, it is often not routinely added to total parenteral nutrition (TPN) formulations. When selenium is not added, patients are at risk for selenium deficiency. This report describes such a patient. He had several operations for colon cancer, including a massive resection of the small bowel that resulted in a short bowel and a fistula. TPN was started after his last operation. After he was discharged, he had a normal, active lifestyle, except that he limited oral intake to water and an occasional soft drink. After 3 years of almost exclusive nourishment by TPN, he developed whitened nail beds. Investigation for possible trace element deficiency resulted in a finding that he had very low levels of selenium in his blood. He did not have any of the cardiac or skeletal muscle abnormalities that have been associated with selenium deficiency. After supplementation with selenium, his blood levels of selenium rose and the nail bed changes were reversed.

Stab wounds to the chest: a retrospective review of 100 consecutive cases.

In a retrospective review of 100 consecutive cases of stab wounds to the chest, 44 patients were successfully treated with tube thoracostomy, 14 patients required thoracotomy, 17 patients with small pneumothoraces were observed, and 25 patients were asymptomatic. The overall mortality was 4%, operative mortality was 7.1%, and the mortality rate for cardiac injuries was 50%. Of the eight patients with cardiac injuries, three were dead on arrival to the hospital and one patient died in the operating room. Patients treated with tube thoracostomy had a shorter hospital stay than patients managed by observation alone. Our findings support the opinion that asymptomatic patients (normal chest x-rays) may be discharged after 24 hours of observation and asymptomatic patients with nonprogressive small pneumothoraces (less than 20%) not requiring a chest tube may be discharged after 48 hours of observation. All patients should have close outpatient follow-up.

Tracheopleuropulmonary injuries following enteral tube insertion.

Eighty-three cases of tracheopleuropulmonary injuries complicating enteral tube feeding are analyzed to identify the patterns of injury, and precipitating factors and ways to avoid them. Six new cases observed by the authors and 77 other cases cited in British literature between 1976 and 1987 are presented. In recent years, reports of this complication have been increasing, apparently in a geometrical progression: 8%, 18%, and 74% were reported between 1976 to 1979, 1980 to 1983, and 1984 to 1987, respectively. Sixty-one percent occurred in patients aged 60 years or older. Most of the patients (84%) were seriously ill, which compounded their complications. Seventy-four percent of all injuries were committed by house staff; the narrow bore tube with guide wire was used in 77% of cases. Less than reliable methods were used to confirm tube position in most instances. The presence of cuffed endotracheal tubes did not offer protection. The patients on mechanical ventilation tended to deteriorate if they developed a pneumothorax once the malpositioned tubes were removed. Of the cases reviewed for this report, 18 deaths occurred; 72% being directly related to the tube injuries. Lack of awareness, inadequate confirmatory methods, and insufficient supervision accounted for most of these preventable complications. Educating house/nursing staff in the use of the new tubes, closer supervision, and the application of equal measures of care and caution as employed in other invasive and potentially dangerous procedures are recommended to avoid disastrous outcome.

The wandering bullet.

The phenomenon of bullet embolization has been documented in various organs or major organ systems. A case report of a gunshot wound injury to the left hemithorax with penetration of the esophagus and embolization to the stomach is presented. Diagnostic evaluation and therapy are discussed.

Candida sepsis.

Thirty cases of Candida sepsis occurring at Howard University Hospital between January 1983 and December 1985 were studied. A retrospective analysis was done to determine which risk factors or methods of treatment led to higher morbidity and mortality. Nosocomial infections with fungi are becoming more widespread as patients survive illnesses once deemed terminal. Patients had positive blood cultures for Candida accompanied by signs of systemic sepsis. Risk factors included diabetes, central hyperalimentation, malignancy, intraabdominal abscesses, and fistulae. The correlation between the total dose of amphotericin administered and patient recovery was analyzed.

Chylothorax: an omnipresent reality in thoracic surgical procedures.

Loss of integrity of the thoracic duct will produce a chylous thoracic effusion. latrogenic chylothorax occurring during an intrathoracic surgical procedure in the vicinity of the thoracic duct is an omnipresent reality. The fluid is characteristically milky in appearance, sterile, and high in fat content.There seems to be a general agreement that initial management be conservative, namely, dietary control and adequate drainage. The success of conservative management will depend on collateral lymphatic channels developing. If conservative measures fail, thoracotomy for ligation of the duct is indicated. When to terminate nonoperative therapy and opt for operative is controversial.

Vascular access in the cancer patient.

Patients requiring frequent blood sampling and/or frequent intravenous fluid administration can be difficult to manage clinically once peripheral veins become exhausted. Not only can peripheral vascular access be difficult in these patients, but patients begin to dread the attempts at blood sampling and intravenous line placement more than the chemotherapy regimen.At Howard University Hospital, several different types of commercial vascular access devices have been employed that afford reliable and dependable use in cancer patients requiring chemotherapy and blood monitoring. With the increased use of these devices, one unpleasant aspect in the management of the cancer patient, that of repeated attempts at vascular access, can be eliminated.

Superior mesenteric vein thrombosis: a case report.

Superior mesenteric vein thrombosis is an abdominal emergency that is rarely diagnosed early. Abdominal pain, vomiting, fever, and hematochezia are the characteristic presenting complaints. Tenderness, distension, and diminished intestinal sounds were the prominent abdominal physical findings in this case and were often associated with tachycardia and hypotension. This is a case that demonstrates all the nonspecifics, and one in which the patient survived beyond all others reported in the literature to date.

Computed tomography of adult colonic intussusception: clinical and experimental studies.

The CT features of a case of adult ileocolic intussusception and of experimentally induced ileocolic, cecocolic, and colocolic intussusceptions are presented. Both the clinical and experimental cases demonstrated (1) "target" masses with enveloped, eccentrically located areas of low density and (2) interspersed low- and high-density stripes within the intussusception producing a "layered" or "stratified" pattern. This layered pattern of abdominal masses may be characteristic of intussusceptions regardless of location.

Naloxone in septic shock: report of two cases.

Two cases are reported describing the use of intravenous naloxone in surgical patients with prolonged hypotension unresponsive to conventional intensive care, including dopamine, intravenous fluids, diuretics, and steroids.The findings were in agreement with those of previous reports suggesting that endorphins may contribute to the hypotension of sepsis and that naloxone's antagonistic effect on endorphin may have therapeutic value in the treatment of septic shock.

Penetrating neck wounds.

Over a 15 year period 120 patients with neck injuries that penetrated the platysma were studied. Appropriate treatment was initiated in the emergency room. Sixty-one patients underwent exploration and 59 were observed. Two of the observed patients later required delayed operation. In 9.2 percent of the patients, two or more injuries were present within the neck, whereas in 30 percent the neck injury was only one of many bodily injuries. Length of hospital stay for the operative group of patients was 9 days and for the nonoperative group 5 days. There was one death. The complication rates in the operative and nonoperative groups were 2.5 and 1.7 percent, respectively. The major structures injured were within the venous system. The neck injuries were classified according to three zones defined by Saletta and Jones and their co-workers [4,5]. The majority were Zone II injuries. Our morbidity and mortality rates are slightly lower than those reported in most series. This review supports the concept that therapy for penetrating injuries to the neck should be individualized.