Blunt traumatic rupture of the thoracic aorta: an epidemiological perspective

A study was conducted from 1 July 1991 to 30 June 1994 to determine the incidence of blunt traumatic rupture of the thoracic aorta (RTA) in a defined area of inner-metropolitan Sydney. The study group consisted of 30 subjects with RTA following falls, rail or road accidents, who were taken by ambulance to the regional trauma centre or directly to forensic pathology. The incidence of RTA in the resident population of 330,000 was in the range 20-30/10(6)/year. There was one survivor in the series, with 24 scene deaths and five deaths en route to hospital. Road accidents were responsible for 57% of incidents. RTA was found in 36% of the fatalities that occurred as a result of car and motorbike accidents. This was 5 times more common than that observed in pedestrian deaths (P < 0.005). Twenty-seven subjects (90%) had at least one co-existent critical or lethal injury. Outcome may be improved by increasing awareness of the high prevalence of RTA in shocked car- and motor-bike-accident victims and stressing the importance of rapid transport of such cases to an appropriate hospital.

Postmenopausal estrogens and progestogens and the incidence of gynecologic cancer

We reviewed the published medical literature to assess the impact of the use of estrogens, with and without progestogens, on the incidence of gynecologic cancer in postmenopausal women. Long-term use of an estrogen preparation that is not accompanied by a progestogen is associated with a large increase in the risk of endometrial cancer, an association that almost certainly is a causal one. The incidence of endometrial cancer in women who receive combined estrogen-progestogen therapy is not elevated to nearly the same degree. There are suggestions that, depending on the particular combined regimen, the incidence need not be elevated at all beyond that of a women who has never taken hormones. The occurrence of other forms of gynecologic cancer appear not to be associated with the use of unopposed estrogens, though relevant data on cervical cancer are sparse. The relation of ovarian, cervical and vulvar cancer to the prior use of combined estrogen-progestogen therapy has only begun to be evaluated.

A population-based study of outcome after injury to car occupants and to pedestrians

OBJECTIVE

The literature indicates that trauma center pedestrian mortality rates approximate twice that of injured car occupants. This study was performed to test the hypothesis that outcomes will be similar given similar degrees of injury severity if analyzed from an epidemiologic perspective. Differences are expected in the cause and place of death because of different injury profiles.

DESIGN

Prospective population-based study.

METHODS

The study group consisted of all adult car occupants and pedestrians sustaining major injury -- Injury Severity Score (ISS) of >15 -- in a defined area of central Sydney from mid-1991 to mid-1994.

MAIN RESULTS

The study included 65 car occupants (median ISS,32) and 101 pedestrians (median ISS,34). Major abdominal injury (p = 0.003) and thoracic aortic disruption (p = 0.06) were more common in car occupants, but major injury to the brains (p = 0.004), lower extremity long bone fractures (p = 0.0005), and thoracolumbar fractures (p = 0.01) occurred more frequently in pedestrians. The overall car occupant mortality was 38% compared with 46% in the pedestrians (p = 0.37). Seventy-two percent of car occupant fatalities occurred in the field, most commonly from ruptured thoracic aorta, whereas 63% of pedestrian deaths occurred in hospital (p = 0.005), most commonly from head injury.

CONCLUSION

These findings have important implications for prehospital care. A policy of "scoop and run" is advocated for injured car occupants in shock because of the high frequency of aortic and abdominal injuries. Advanced life support measures are appropriate at the scene to stabilize the airway and to protect the entire spine in pedestrians with multiple injuries because of the high frequency of brain and vertebral trauma.

Abdominal trauma in the pregnant patient

Physicians who care for pregnant women must be prepared to evaluate and treat abdominal trauma during pregnancy. The evaluation and management of even minimal abdominal trauma in pregnancy is often problematic, and the use of laboratory tests, fetal monitoring, radiography and ultrasonography depends on the extent of the trauma and the viability of the fetus. Intervention ranges from reassurance to cardiopulmonary resuscitation and surgery. Common laboratory studies include a complete blood count, coagulation panel, urinalysis and blood type and screen. Ultrasonography is useful for evaluation of fetal weight and status of amniotic fluid, but tocodynamometry is more sensitive for diagnosis of placental abruption. Patients with minimal trauma and no bleeding, uterine contractions or abdominal pain can be safely discharged after four to six hours of monitoring, but patients with any of these findings should be admitted to the hospital for overnight observation with continuous fetal heart rate monitoring.

The effect of alkalinisation of lignocaine on axillary brachial plexus anaesthesia

Alkalinisation of local anaesthetic drugs is a controversial technique for improving regional blockade. Forty-two patients scheduled for upper limb surgery received axillary brachial plexus anaesthesia using a cannula technique. Patients were randomly allocated to receive either lignocaine 1.5% with 1 in 200,000 adrenaline (pH = 4.2) or lignocaine 1.5% with 1 in 200,000 adrenaline (pH = 7.2). There was no significant difference in the incidence of satisfactory blockade or distribution of anaesthesia between the two groups. The percentage of patients with complete anaesthesia at 10, 20 and 30 min following injection was significantly increased in the alkalinized group with regard to the ulnar and median nerves, and the median cutaneous nerve of the arm (p < 0.05). In the alkalinized group, there was a significant reduction in the time to useful anaesthesia and a reduced requirement for adjuvants (p < 0.05). There was no effect on the duration of anaesthesia.

Moving on: autism and movement disturbance

Many authors have reported on the presence of movement disturbance symptoms in some individuals with autism. Typically, these symptoms have been seen as peripheral to autism or as belonging to a co-occurring syndrome. Some have dismissed these symptoms as having no apparent impact on the presence of behaviors defined as the core characteristics of autism. In this article we considered the relation between symptoms of movement disturbance and symptoms of autism and included our speculative and exploratory analyses of shared symptoms. The analyses point out the difficulties posed by current definitions of autism. We proposed that symptoms of movement disturbance can affect a person's experience of life and how he or she may be perceived by others.

Outcome of patients with haemorrhagic shock: an indicator of performance in a trauma centre

The survival rate of patients admitted to the Royal Prince Alfred Hospital (RPAH) from the central Sydney area with a major injury has improved since regionalization of trauma services in early 1992. This improvement has been attributed to education, better hospital care and changing trauma epidemiology. This study was conducted to assess whether the outcome of patients admitted with haemorrhagic shock had improved. This is proposed as a more subtle indicator of hospital performance than overall survival rates. A prospective before and after study was carried out comparing outcome in the 18 months preceding 1 January 1992 with that in the subsequent 18 months. Entry criteria to the study included all primary retrievals from the central Sydney area to RPAH with injury severity scores (ISS) > 15. Outcomes were compared generally and in those who were in a state of haemorrhagic shock (systolic blood pressure < or = 90 mmHg) on arrival at the emergency department. Three hundred and eight patients were entered into the study. Stratification showed similar numbers, demographic features and mechanisms of injury in the two groups. Forty patients were in a state of haemorrhagic shock on admission. The overall mortality was reduced from 31% to 11% (P < 0.001) over the two phases of the study. The mortality from blood loss in the 40 shocked patients fell from 10/25 in the first period to 2/15 (P = 0.07) in the latter. These improved survival rates were felt to reflect the value of the educational and organizational initiatives introduced following designation of the hospital as a trauma centre.

The acceptance of computer assisted learning by medical students

The use of computer assisted learning (CAL) in the medical undergraduate curriculum is increasing. Little is known regarding the acceptability of CAL among medical students. The present study was conducted to investigate the possible anxiety generated by and the acceptability of CAL among medical students. One hundred and twenty-six students completed a questionnaire after using a software package which has been as an adjunct in teaching urology. The present study demonstrates that there was little anxiety experienced by the students when using CAL and furthermore that there was a high level of acceptance for this type of instruction. This is encouraging for medical educators involved in producing multimedia packages for teaching medicine and surgery.

Effect of copper depletion and repletion on lymphocyte blastogenesis and neutrophil bactericidal function in beef heifers

Thirty-two beef heifers were used to examine the effect of dietary copper depletion and repletion on neutrophil and lymphocyte functions. Heifers allotted to the control group (C+; n = 8) were fed a basal roughage/concentrate diet with Cu-sulfate supplementation (Cu > or = 8 ppm). To induce a Cu deficiency (depletion phase d 0 to 60), treated (T; n = 24) heifers received a diet supplemented with sulfur (.3% of diet) and sodium molybdate to achieve a Cu:Mo ratio of 1:1.5. Liver biopsies were collected on d 0, 27, and 60. Despite random allocation, T heifers had lower initial liver Cu concentrations (P < .01) than C+ heifers. At the start of the repletion phase (d 0, equal to d 60 of depletion), treated heifers were allotted by liver Cu concentration to three treatments (n = 8/treatment): Cu sulfate (S; Cu = 10 ppm), Cu proteinate (P; Cu = 10 ppm), or a negative control (C-) that remained on Mo and S supplementation. During the repletion phase, livers were biopsied on d 0, 14, and 45. By d 45, both S and P heifers had greater (P < .05) liver Cu concentrations than C- heifers. For both depletion and repletion phases, no treatment differences were detected in liver Mo or S concentrations. Jugular blood was collected on d 0, 27, and 55 of the depletion phase and d 0, 13, and 42 of the repletion phase. Neutrophils were isolated and incubated with Staphylococcus aureus to determine neutrophil bactericidal capacity (NBC).(ABSTRACT TRUNCATED AT 250 WORDS)

Epidural infusion of alfentanil or diamorphine with bupivacaine in labour--a dose finding study

Following induction of epidural analgesia with 0.375% bupivacaine, 120 healthy parturients were randomly assigned in a double blind fashion to one of eight infusion groups. All received 8 ml.h-1 of 0.125% bupivacaine either alone (control group), or with alfentanil at 133, 266 or 400 micrograms.h-1 (groups A1-A3) or with diamorphine at 133, 266, 400 or 533 micrograms.h-1 (groups D1-D4). Significantly longer top-up intervals were achieved with the two highest doses of both alfentanil and diamorphine when compared with bupivacaine alone (p < 0.01), making the minimum effective doses 266 micrograms.h-1 of alfentanil and 400 micrograms.h-1 of diamorphine. Perineal analgesia was better in all the opioid groups compared with the control group (p < 0.05). The intensity of motor block was greater in the control group (p < 0.05). The incidence of pruritus did not differ between groups. The highest dose of diamorphine caused significantly more nausea. No significant neonatal side-effects were demonstrated.

The benefits of using the loop ligature (Endoloop) laparoscopic sterilization procedure in a residency program

This study was conducted to determine the impact of the addition of the loop ligation (Endoloop) technique on choice of sterilization surgery in our residency teaching program and to investigate significant differences between this technique and other methods performed at our hospital. A retrospective study of all patients undergoing interval tubal sterilization at Tampa General Hospital in 1989 and 1991 was undertaken. Data were analyzed to determine the frequency of sterilization methods and differences between the loop ligation method and the other procedures performed; p values of less than 0.05 were considered significant. Sixty-one patients in 1989 and 75 in 1991 qualified for the study. Five methods of interval sterilization were performed: loop ligation, minilaparotomy, colpotomy, laparoscopic bipolar fulguration, and Silastic ring application. The frequency of the loop ligature technique increased from 0% in 1989 to 40% in 1991. There were no significant differences in operative time and complication rate among the loop method and other procedures. The loop ligature (Endoloop) method of laparoscopic sterilization does not significantly change the length of surgery, blood loss, or complication rate compared to the other laparoscopic techniques used in our residency program. This method provides a definitive tissue diagnosis, eliminates the risk of thermal injury, theoretically provides an opportunity of later tubal reanastomosis, and subjectively helps develop laparoscopic skills.

Vitamin A modulation of xenobiotic-induced hepatotoxicity in rodents

Vitamin A (VA, retinol) has been shown to modulate cells of the immune system. When rats are pretreated with VA (75 mg/kg/day) for 7 days, there is greatly potentiated liver damage upon subsequent exposure to hepatotoxicants such as CCl4. This potentiated damage can be blocked by superoxide dismutase or catalase, suggesting that reactive oxygen species are playing a major role in the increased liver injury. The studies reported here examined VA-induced modulation of CCl4 hepatotoxicity in different strains of male rats, female rats, and different strains of male mice. Also, the role of VA-induced weight loss on potentiation of CCl4 injury was investigated. Rats or mice were dosed with VA (retinol) at 75 mg/kg/day, po, for 7 days. In an additional VA dose-response study, mice were given VA at 18.8, 37.5, or 75 mg/kg/day, po, for 7 days. On day 8 they were given a dose of CCl4 which elicited mild hepatic damage. On day 9 they were necropsied. Male and female Sprague-Dawley rats, and male Fischer-344 and athymic nude rats pretreated with VA had an approximately 10-fold increase in liver damage as compared to vehicle controls. Pretreatment of male Balb/C, C3H/HeJ, Swiss-Webster, or athymic nude mice resulted in a marked reduction of CCl4-induced hepatic damage. In the dose-response study in mice, increasing doses of VA elicited increasing amounts of protection from CCl4-induced liver injury. Paired feeding studies revealed that VA-induced weight loss (or decreased weight gain) had no effect on subsequent VA-induced potentiation (rats) or protection (mice) from hepatic damage caused by CCl4.(ABSTRACT TRUNCATED AT 250 WORDS)

Formative assessment: a student perspective

An educator's view would be that formative assessment has an important role in the learning process. This study was carried out to obtain a student perspective of the place of formative assessment in the curriculum. Final-year medical students at Royal Prince Alfred Hospital took part in four teaching sessions, each structured to integrate teaching with assessment. Three assessment methods were used; the group objective structured clinical examination (G-OSCE), structured short answer (SSA) questions and a pre/post-test multiple choice questionnaire (MCQ). Teaching sessions were conducted on the subject areas of traumatology, the 'acute abdomen', arterial disorders and cancer. Fifty-five students, representing 83% of those who took part in the programme, responded to a questionnaire where they were asked to rate (on a 5-point Likert scale) their response to general questions about formative assessment and 13 specific questions concerning the comparative value of the three assessment modalities. Eighty-nine per cent of respondents felt that formative assessment should be incorporated into the teaching process. The SSA assessment was regarded as the preferred modality to reinforce previous teaching and test problem-solving skills. The MCQ was the least favoured assessment method. The effect size variable between the total scores for the SSA and MCQ was 0.64. The variable between G-OSCE and SSA/MCQ was 0.26 and 0.33 respectively. Formative assessment is a potentially powerful method to direct learning behaviour. Students should have input into the methods used.

A survey of rural road fatalities

This study is a retrospective case series analysis of all 82 road deaths occurring in the Orana Area Health Service (OAHS) over the 2 year period 1989-90. The OAHS services a population of 112,800 in an area of 199,077 km2 in north-west New South Wales. The aim of the study was to document timing, place and cause of deaths, severity of injuries, pre-hospital management of victims, and a TRISS analysis of outcome. This was done using ambulance, hospital, police and autopsy reports. Seventy-two (88%) of the victims were motor vehicle occupants, five (6%) were motorcyclists and four (5%) were pedestrians. The median ambulance response time to the scene of the accident was 17 min (range 2-103 min). All deaths occurred within 24 h of injury with 65 (79%) of the victims being dead at the scene, nine (11%) dying en-route and eight (10%) reaching hospital alive. A TRISS analysis was performed on 51 deaths and 8% (4/51) of these had a greater than 50% probability of survival. Of the victims that had inevitable deaths according to TRISS, 11% (5/47) may have survived if pre-hospital care arrived sooner. Reduction in the rural road toll is achievable through preventative measures and strategies to improve access to care and administration of pre-hospital care.

Complication of hard cervical collars in multi-trauma patients

All multi-trauma patients with suspected cervical spine injury should have their cervical spine protected while other life-threatening injuries are being managed. The application of a hard cervical collar is an acceptable method of temporarily immobilizing the cervical spine. Two cases of significant occipital pressure ulceration associated with the use of hard cervical collar are presented.

Value of the prospective 'before and after' study as a methodology to evaluate outcome in a trauma centre

A series of interventions (administrative, clinical and educational) was introduced to improve the quality of trauma care at Royal Prince Alfred Hospital, the designated trauma centre for the Central Sydney Area Health Service (CSAHS). A prospective, 'before and after' study was conducted to assess changes in outcome following the introduction of these measures. The trauma centre survival rate for patients admitted with serious injury (Injury Severity Scores > 15) increased significantly, from 72% in the nine months before trauma centre designation to 89% in the nine months after (P = 0.005). The peer review designated, potentially avoidable death rate did not change significantly over the two study periods, remaining in the 20-30% range. Similarly the unexpected death rate (TRISS) did not change significantly, remaining in the 20-45% range. A trend to a lower trauma centre mortality in those arriving with a systolic blood pressure < or = 90 mmHg was noted. Seven out of 14 patients 'at risk' from exsanguination died in the first 9 months compared with one out of seven in the second 9 months (P = 0.17). An unexpected finding was a change in the degree of injury severity and physiological status in patients arriving at the trauma centre. The Injury Severity Scores were significantly lower (P = 0.008) and the Revised Trauma Scores significantly higher (P = 0.0006) in the latter 9 months of the study. It was concluded that the improved trauma centre survival rate was a reflection of a reduced hospital mortality from haemorrhagic shock in conjunction with a lesser degree of injury severity in patients admitted from the CSAHS.

Integration of the surgical specialties into an innovative undergraduate curriculum

A dilemma exists concerning the most effective way to incorporate surgical specialty teaching into an innovative undergraduate curriculum. Should the specialties form part of the core curriculum or should they be available as electives? The aim of this study is to describe an educationally sound and time-effective way to give all students an exposure to the surgical specialties while maintaining the philosophy of an innovative curriculum. The SCORPIO method was used, on a trial basis, in 1992 to teach cardiothoracic surgery, neurosurgery, plastic surgery and urology to fourth-year medical students at a university teaching hospital. The teaching was evaluated by comparing group pretest performance with a posttest assessment given one month after each of the teaching sessions. Student perceptions were assessed by a questionnaire and a time analysis was carried out comparing SCORPIO with the traditional ward tutorial system. Students completed the sequence pretest, teaching and posttest on 169 occasions. Group performance increased from a pretest mean 28% (SD16) to a posttest mean 44% (SD13) P < 0.0001. Student acceptance was favourable, with high ratings given to the structured, problem-based style of teaching. The time to run the programme was one-eight that to teach by the ward tutorial system. This teaching model is a practical way to incorporate the surgical specialties into the core curriculum of a school moving towards a student centred, problem-based, integrated curriculum.

Factors affecting outcome in the resuscitation of severely injured patients

This is a retrospective, hospital based study of the resuscitative management of 40 consecutive, multitrauma patients (Injury Severity Score (ISS) > 25) admitted directly from an inner metropolitan environment over a one year period. The aim was to identify physiological, anatomical and time variables that correlated with an adverse outcome. Such information would facilitate the development of management protocols to improve future care. The clinical management of airways, breathing, circulation and head injury was reviewed in both the pre-hospital and Emergency Department (ED) phases of care. Eleven patients died during the resuscitative phase, 10 from blood loss and one from head injury. Nine patients died during the definitive care phase, seven from head injury and two from multiple organ failure. Scene hypotension (systolic blood pressure < or = 80 mmHg), ED Glasgow Coma Scale < 9, ISS > or = 50, and Revised Trauma Score < or = 4 were variables that correlated strongly with fatal outcomes. The median pre-hospital time was 33 min for those hypotensive in the field. The median ED time was 70 min for hypotensive patients who went to operating theatres. Survival following severe trauma may be increased by avoiding secondary insults in head injured patients and improving the management of haemorrhagic shock. The time frame from accident to operating theatre should be kept under 90 min. Warmed blood, fresh frozen plasma and platelets should be used early in the resuscitation. An early move to definitive control of bleeding should accompany vigorous volume resuscitation.

Impact of pedestrian injury on inner city trauma services

This report describes the epidemiology of pedestrian injury in four inner metropolitan local government areas of Sydney. These data were obtained from the Roads and Traffic Authority of New South Wales. The spectrum of injury and clinical outcome was defined in patients with an Injury Severity Score (ISS) > 15 admitted from the study area, during a 1 year period, to the four inner metropolitan teaching hospitals. The incidence of pedestrian death was 3.3 times the state average of 32/10(6)/year. An average of 235 pedestrians, injured in the study area, were hospitalized each year during the period 1987-89. On average 24 pedestrians died each year, seven at the scene and 17 in hospital. Fifty patients (ISS > 15) were admitted to the four teaching hospitals during a 1 year period 1990-91. Forty-five were adults and five children. Multiplicity of injury was seen in 68% of patients. The pelvis and lower extremities were involved in 70%, the head in 66% and chest in 42%. The hospital mortality rate was 30% with five patients dying on the first day from blood loss and nine dying during subsequent days from head injury. This study has important implications for trauma service development. Successful clinical management of the severely injured pedestrian requires close co-operation between pre-hospital and hospital care providers. An integrated hospital trauma team response is mandatory to ensure appropriate management of what is often a shocked, hypoxic, head-injured patient.

A model to teach trauma care to medical students

The following integrated trauma teaching model has been developed in response to perceived deficiencies of organized trauma content in many undergraduate surgical programmes. This method has combined structured teaching and clinical clerkship. First, a short lecture is given to the student body giving an overview of the subject. Small groups then rotate through a series of teaching stations, each structured to represent a different level in the hierarchy of management priorities involved in the care of a trauma patient. The educational value of a 150 minute teaching session was evaluated by comparing group performance in a pre-test given several days before with a post-test immediately after teaching. Forty one Year IV students increased their mark, out of a possible total of 30, from a pre-test mean 15 (SD3) to a post-test mean 21 (SD3). Thirty two year VI students increased their marks from a mean 18 (SD3) to a mean 24 (SD2). Both increases are highly significant (p < 0.001). The model has proved to be an effective way to teach students trauma skills in preparation for a subsequent clerkship or internship.

Role of the pre-test in the progressive assessment of medical students

A prospective, randomized, controlled trial was conducted to see if a pre-test, given immediately before teaching, improved performance in a subsequent post-test. The study was also used to assess the educational value of a structured teaching method. Third year medical students were randomized into study and control groups. In phase I, the study group completed a subject-specific multiple choice question (MCQ) pre-test immediately before a teaching demonstration on vascular disorders. The control group completed a placebo pre-test. At the completion of teaching both groups did the same subject-specific post-test. The experiment was repeated in phase II where the groups were crossed over and traumatology was the subject of the demonstration. In both phases of the experiment there were no significant differences between the post-test marks of the experimental and control groups (P = 0.128 and 0.397, respectively). The experimental groups did, however, increase their marks significantly when their post-test results were compared with pre-test marks (P less than or equal to 0.0001, phase I and II). It was concluded that the pre-test did not result in a measurable increase in learning. The study did demonstrate that the teaching method was effective as post-instructional knowledge increased by nearly half when compared with pre-test levels.

Effects of amiodarone administration during lactation in Fischer-344 rats

The antiarrhythmic drug, amiodarone, was administered (35 mg/kg, p.o.) once daily to lactating Fischer-344 rats for either the first 7 days of lactation, the first 14 days of lactation, or for the full 24-day lactational period. Treatment with amiodarone resulted in a decrease in maternal weight gain compared to pair-fed vehicle-treated controls, however, neonatal weight gain was not affected. The concentration of amiodarone in the maternal milk was approx. 6-fold higher than its primary metabolite, desethylamiodarone. Plasma levels of amiodarone and desethylamiodarone were higher in maternal rats compared to neonates. Both amiodarone and desethylamiodarone were distributed to neonatal tissues through lactational transfer. The levels of desethylamiodarone were higher in neonatal lung compared to liver at all treatment times. They were also elevated above amiodarone in neonatal lung at all treatment times. The amiodarone levels in neonatal lung and liver were similar.

Intraocular penetration of rifampin in humans

The penetration of rifampin into human aqueous humor was determined in 15 patients undergoing elective cataract surgery. Between 0.9 and 5.5 h after administration of a single 600-mg oral dose, concentrations ranged from 6.0 to 21.5 mg/liter in serum and from less than 0.2 to 1.3 mg/liter in aqueous humor.