Aspirin and Tranexamic Acid for Coronary Artery Surgery (ATACAS) Trial: rationale and design

BACKGROUND

Despite some concern that recent aspirin ingestion increases blood loss after coronary artery surgery, there is some evidence that this may reduce thrombotic complications. In contrast, antifibrinolytic drugs can reduce blood loss in this setting, but there is concern that they may increase thrombotic complications. Published guidelines are limited by a lack of large randomized trials addressing the risks and benefits of each of these commonly used therapies in cardiac surgery. The ATACAS Trial is a study comparing aspirin, tranexamic acid, or both, with placebo in patients undergoing on-pump or off-pump coronary artery surgery.

METHODS

We discuss the rationale for conducting ATACAS, a 4600-patient, multicenter randomized trial in at-risk coronary artery surgery, and the features of the ATACAS study design (objectives, end points, target population, allocation, treatments, patient follow-up, and analysis).

CONCLUSIONS

The ATACAS Trial will be the largest study yet conducted to ascertain the benefits and risks of aspirin and antifibrinolytic therapy in coronary artery surgery. Results of the trial will guide the routine clinical care of patients in this setting.

Gender differences in outcome in patients with hypotension and severe traumatic brain injury

BACKGROUND

Animal studies have identified hormonal influences on responses to injury and recovery, creating a potential gender effect on outcome. Progesterone and oestrogen are thought to afford protection in the immediate post-injury period, suggesting females have an advantage, although there has been limited evidence of this in human outcome studies.

METHODS

This study examined the influence of gender on outcome in 229 adults (151 males), aged >17 years, with severe blunt head trauma, initial GCS <9 and hypotension, recruited into a randomised controlled trial of pre-hospital hypertonic saline resuscitation versus conventional fluid management. Outcome was measured by survival and Glasgow Outcome Scale-Extended version (GOS-E) scores at 6 months post-injury.

RESULTS

Females recruited into the study had a higher mean age. Females were more likely to be injured as passengers and pedestrians and males as drivers or motorcyclists. There were no gender differences in GCS or injury severity scores, ICP, cerebral perfusion pressure, gas exchange (PaO2/FiO2 ratio), or duration of mechanical ventilation. After controlling for GCS, age and cause of injury, females had a lower rate of survival. They also showed a lower rate of good outcome (GOS-E score >4) at 6 months, but this appeared to reflect the lower rate of initial survival. Those females surviving had similar outcomes to males.

CONCLUSIONS

The study provides no evidence that females fare better than males following severe TBI, suggesting rather that females may fare worse.

Early decompressive craniectomy for patients with severe traumatic brain injury and refractory intracranial hypertension--a pilot randomized trial

PURPOSE

The aims of this study were to test the feasibility and to assess potential recruitment rates in a pilot study preliminary to a phase III randomized trial of decompressive craniectomy surgery in patients with diffuse traumatic brain injury (TBI) and refractory intracranial hypertension.

MATERIALS AND METHODS

A study protocol was developed, inclusion and exclusion criteria were defined, and a standardized surgical technique was established. Neurologic outcomes were assessed 6 months after injury with a validated structured questionnaire and a single trained assessor blind to treatment group.

RESULTS

During the 8-month pilot study at a level 1 trauma center in Melbourne, Australia, 69 intensive care patients with severe TBI were assessed for inclusion. Six patients were eligible, and 5 (8%) were randomized. Six months after injury, 100% of patients received outcome assessments. Key improvements to the multicenter Decompressive Craniectomy study protocol were enabled by the pilot study.

CONCLUSIONS

In patients with severe TBI and refractory intracranial hypertension, the frequency of favorable neurologic outcomes (independent living) was low and similar to predicted values (40% favorable). A future multicenter phase III trial involving 18 neurotrauma centers with most sites conservatively recruiting at just 25% of the pilot study rate would require at least 5 years to achieve an estimated 210-patient sample size. Collaboration with neurotrauma centers in countries other than Australia and New Zealand would be required for such a phase III trial to be successful.

Saline or albumin for fluid resuscitation in patients with traumatic brain injury

BACKGROUND

The Saline versus Albumin Fluid Evaluation study suggested that patients with traumatic brain injury resuscitated with albumin had a higher mortality rate than those resuscitated with saline. We conducted a post hoc follow-up study of patients with traumatic brain injury who were enrolled in the study.

METHODS

For patients with traumatic brain injury (i.e., a history of trauma, evidence of head trauma on a computed tomographic [CT] scan, and a score of < or =13 on the Glasgow Coma Scale [GCS]), we recorded baseline characteristics from case-report forms, clinical records, and CT scans and determined vital status and functional neurologic outcomes 24 months after randomization.

RESULTS

We followed 460 patients, of whom 231 (50.2%) received albumin and 229 (49.8%) received saline. The subgroup of patients with GCS scores of 3 to 8 were classified as having severe brain injury (160 [69.3%] in the albumin group and 158 [69.0%] in the saline group). Demographic characteristics and indexes of severity of brain injury were similar at baseline. At 24 months, 71 of 214 patients in the albumin group (33.2%) had died, as compared with 42 of 206 in the saline group (20.4%) (relative risk, 1.63; 95% confidence interval [CI], 1.17 to 2.26; P=0.003). Among patients with severe brain injury, 61 of 146 patients in the albumin group (41.8%) died, as compared with 32 of 144 in the saline group (22.2%) (relative risk, 1.88; 95% CI, 1.31 to 2.70; P<0.001); among patients with GCS scores of 9 to 12, death occurred in 8 of 50 patients in the albumin group (16.0%) and 8 of 37 in the saline group (21.6%) (relative risk, 0.74; 95% CI, 0.31 to 1.79; P=0.50).

CONCLUSIONS

In this post hoc study of critically ill patients with traumatic brain injury, fluid resuscitation with albumin was associated with higher mortality rates than was resuscitation with saline. (Current Controlled Trials number, ISRCTN76588266 [controlled-trials.com].).

Early modifiable factors associated with fatal outcome in patients with severe traumatic brain injury: a case control study

OBJECTIVE

Survival of patients with severe traumatic brain injury may be improved by minimizing secondary brain injury. We aimed to identify potentially modifiable contributors to secondary brain injury that may persist and adversely affect patient outcome.

DESIGN

Retrospective case control study. Nonsurviving patients with traumatic brain injury were selected and matched 1:1 for age, Glasgow Coma Scale score, Abbreviated Injury Scale: Head (AISHEAD), Revised Trauma Score, and Injury Severity Score with survivors. Potentially modifiable contributors to secondary brain injury were examined and compared in both groups.

SETTING

A level I trauma center in Melbourne, Australia.

PATIENTS

Patients with traumatic brain injury caused by blunt trauma with an AISHEAD >or=4 were identified from a prospective intensive care database.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Between January 1, 1999, and July 30, 2000, 74 patients, including 37 nonsurvivors, were identified. By design, the groups were well matched for injury severity and baseline conditions. In nonsurvivors, mean arterial pressure was similar to that of survivors at hospital arrival but was lower at 4 hrs after arrival (71 +/- 16 vs. 80 +/- 15 mm Hg, p = .016). A mean arterial pressure <or=65 mm Hg during this 4-hr period was associated with a four-fold increase in the odds of nonsurvival (95% confidence interval, 1.25-12.8). Intracranial pressure monitoring and intensive care unit admission tended to be initiated later in nonsurvivors, potentially delaying recognition and management of inadequate cerebral perfusion pressure. In nonsurvivors, hypothermia did not normalize during the first 24 hrs after injury.

CONCLUSIONS

In patients with severe traumatic brain injury, lower blood pressure in the first 4 hrs after admission was associated with mortality and may have increased the rate of secondary brain injury. Outcomes of patients with severe traumatic brain injury may potentially be improved by early targeting of the higher mean arterial pressure observed in survivors (mean arterial pressure 80 mm Hg), which may facilitate improved cerebral perfusion. Slower initiation of intracranial pressure monitoring and of intensive care unit admission may also have adversely affected outcomes, whereas persistent hypothermia was associated with nonsurvival.

External ventricular drain infections are independent of drain duration: an argument against elective revision

Object

The authors explored the relationship among the duration of external ventricular drainage, revision of external ventricular drains (EVDs), and cerebrospinal fluid (CSF) infection to shed light on the practice of electively revising these drains.

Methods

In a retrospective study of 199 patients with 269 EVDs in the intensive care unit at a major trauma center in Australasia, the authors found 21 CSF infections. Acinetobacter accounted for 10 (48%) of these infections. Whereas the duration of drainage was not an independent predictor of infection, multiple insertions of EVDs was a significant risk factor. Second and third EVDs in previously uninfected patients were more likely to become infected than first EVDs. An EVD infection was initially identified a mean of 5.5 ± 0.7 days postinsertion (standard error of the mean); these data—that is, the number of days—were normally distributed.

Conclusions

This pattern of infection is best explained by EVD-associated CSF infections being acquired by the introduction of bacteria on insertion of the drain rather than by subsequent retrograde colonization. Elective EVD revision would be expected to increase infection rates in light of these results, and thus the practice has been abandoned by the authors' institution.

Factors predicting cervical collar-related decubitus ulceration in major trauma patients

STUDY DESIGN

Retrospective medical record and electronic database audit to ascertain the incidence and predictors of cervical collar-related decubitus ulceration (CRU).

OBJECTIVE

To determine the incidence and risk factors associated with the development of CRU in major trauma patients immobilized in Philadelphia cervical collars.

SUMMARY OF BACKGROUND DATA

Cervical spine immobilization requires the utilization of a cervical collar before spinal clearance, which may be complicated by CRU and increased morbidity.

METHODS

From a trauma registry database at a level 1 trauma center, 299 major trauma patients admitted over a 6-month period were identified. Predictors of CRU were retrospectively examined and assessed for relative importance using medical records and prospective infection control and radiology databases.

RESULTS

Clinically significant predictors of CRU were ICU admission (P = 0.007), mechanical ventilation (P = 0.005), the necessity for cervical MRI (P < or = 0.001), and time to cervical spine clearance (P < or = 0.001). Time to cervical spine clearance was the major indicator, such that the risk of CRU increased by 66% for every 1 day increase in cervical collar time.

CONCLUSION

In major trauma patients at a level 1 trauma center, the risk of CRU development increased significantly for every day of Philadelphia cervical collar time. Associated increased morbidity may be reduced by measures aimed at earlier cervical spine clearance.

CURRENT CONTROVERSIES IN THE MANAGEMENT OF PATIENTS WITH SEVERE TRAUMATIC BRAIN INJURY

BACKGROUND

Traumatic brain injury is a major cause of mortality and morbidity, particularly among young men. The efficacy and safety of most of the interventions used in the management of patients with traumatic brain injury remain unproven. Examples include the 'cerebral perfusion pressure-targeted' and 'volume-targeted' management strategies for optimizing cerebrovascular haemodynamics and specific interventions, such as hyperventilation, osmotherapy, cerebrospinal fluid drainage, barbiturates, decompressive craniectomy, therapeutic hypothermia, normobaric hyperoxia and hyperbaric oxygen therapy.

METHODS

A review of the literature was performed to examine the evidence base behind each intervention.

RESULTS

There is no class I evidence to support the routine use of any of the therapies examined.

CONCLUSION

Well-designed, large, randomized controlled trials are needed to determine therapies that are safe and effective from those that are ineffective or harmful.

Cervical Spine Clearance in Unconscious Traumatic Brain Injury Patients: Dynamic Flexion-Extension Fluoroscopy versus Computed Tomography with Three-Dimensional Reconstruction

BACKGROUND

An optimal protocol for clearing the cervical spine in unconscious patients with traumatic brain injury remains controversial. Protocols include plain radiographs and computed tomography (CT), and ligamentous injury may be identified with flexion-extension radiographs. We questioned whether cervical CT with three-dimensional (3D) reconstructions may obviate the need for flexion-extension radiology in the detection of occult ligamentous injury.

METHODS

Between July 1999 and November 2001, 276 unconscious traumatic brain injured patients admitted to The Alfred Hospital received cervical spine plain radiographs, CT with 3D reconstructions, and dynamic flexion-extension X-ray studies with fluoroscopy as part of a routine protocol. These patients were identified from a prospective intensive care unit database and all radiology reports were reviewed.

RESULTS

Dynamic flexion-extension X-ray studies with fluoroscopy identified no new fractures or instability; there were no instances of true-positive results. Dynamic flexion-extension was true-negative in 260 of 276 (94%) patients, falsely positive in six patients (2.2%) and falsely negative in one (0.4%) patient. In nine patients, dynamic flexion-extension was inadequate.

CONCLUSION

Dynamic flexion-extension X-ray studies with fluoroscopy delayed cervical spine clearance and were almost always reported as normal. In a cervical spine clearance protocol for unconscious traumatic brain injury patients, dynamic flexion-extension X-ray studies with fluoroscopy did not identify any patients with cervical fracture or instability not already identified by plain radiographs and fine-cut CT (C0 to T2) with 3D reconstructions.

Thromboprophylaxis for intensive care patients in Australia and New Zealand: a brief survey report

PURPOSE

Internationally, there is practice variation concerning optimal thromboprophylaxis for patients in the intensive care unit (ICU). The current practice in Australia and New Zealand is unknown.

METHOD

We conducted a self-administered e-mail survey of 22 Australian and New Zealand ICUs expressing interest in participating in a proposed international randomized trial (PROphylaxis for ThromboEmbolism in Critical Care Trial).

RESULTS

Our response rate was 95.4% (95% CI, 77%-100%). Of participating ICUs, 90.5% (95% CI, 70%-99%) used subcutaneous unfractionated heparin for routine thromboprophylaxis in ICU patients. Low-molecular-weight heparin was reserved for specific high-risk patients in many units.

CONCLUSION

Routine thromboprophylaxis for ICU patients in Australia and New Zealand is similar to Canada but different to France. Optimal thromboprophylaxis for ICU patients is currently unclear in the absence of randomized trial data.

The Trauma Registry as a Statewide Quality Improvement Tool

BACKGROUND

Trauma registries have been developed to describe the pattern of trauma and trauma workload, provide data for research, and to demonstrate changes in patient outcomes. Quality improvement using trauma registries at a system-wide level has been difficult to achieve. In Victoria, Australia, a statewide trauma system and trauma registry has been established to monitor and feedback the process of management and outcomes of major trauma patients across all healthcare providers.

METHODS

The development and implementation of the Victorian State Trauma Registry (VSTR), including its role as a quality monitoring tool and results from the first 2 years of operation, are provided.

RESULTS

More than 80% of major trauma patients are being managed at major trauma services and standardized death rates are comparable with international standards. Quality indicators identify some areas for improvement.

CONCLUSION

VSTR data indicate that the statewide trauma system is working well and provides a method for ongoing monitoring and trauma care feedback.

Clearing the cervical spine in unconscious head injured patients - the evidence

Cervical spine injury occurs in 5-10% of patients with traumatic brain injury (TBI) and the consequences of missing significant cervical injuries in unconscious blunt trauma patients are potentially devastating. An adequate cervical spine clearance protocol for unconscious patients must avoid missed injuries, but must also avoid unnecessary cervical immobilisation and the associated morbidity. Existing protocols include various combinations of plain X-rays, helical CT, dynamic flexion-extension X-rays and MRI. Some clinicians also maintain immobilisation until clinical clearance is eventually enabled by the return of an adequate conscious state. Plain X-rays alone are inadequate and miss 12-16% of cervical injuries. Swimmer's views and/or oblique views identify more injuries, but are frequently inadequate. Helical CT is sensitive to fractures and subluxation/dislocation injuries but may be insufficient to exclude unstable ligamentous injuries. Dynamic flexion-extension fluoroscopy may better identify unstable ligamentous injuries, but at The Alfred Hospital Trauma Centre in Melbourne, this modality was insensitive in the routine protocol and repeatedly missed significant cervical instability. Furthermore at The Alfred Hospital, when routine dynamic flexion/ extension fluoroscopy and helical CT reconstructions were directly compared, flexion/extension identified no new injuries that had not already been diagnosed by early helical CT reconstructions. Cervical MRI is intuitively appealing as it detects ligament, disc interspace, and cord injury more efficiently than other imaging modalities, but MRI also increases cervical clearance times, increases the risks associated with complex transports and is not an ideal acute screening tool. Nevertheless, recently at The Alfred Hospital, extremely high-risk TBI patients have had unstable cervical injuries detected solely by MRI. Current generation multi-slice CT with reconstructions may obviate the need for MRI even in these patients. The current Alfred Hospital cervical clearance protocol for unconscious patients, and the evolutionary steps in its development, will be discussed.

Salines, osmoles and albumin

In 2004, two large randomised multi-centre Australian clinical trials provided new information concerning optimal resuscitation for patients with traumatic brain injury (TBI). One examined hypertonic saline (HTS) and the other, albumin versus saline.( )For the first time in a randomised trial, hypertonic saline was tested for pre-hospital resuscitation of hypotensive patients with traumatic brain injury, and for the first time a resuscitation fluid trial measured long term neurological function as the primary outcome. Despite many potential advantages which may have much greater relevance in the hospital setting, in the paramedic based VICn trauma system, HTS did not improve neurological outcome compared to conventional pre-hospital fluid protocols. Nevertheless, HTS resuscitation was confirmed to be safe in TBI patients and may find application in future pre-hospital military settings where fluid weight is of primary importance. The very large randomised SAFE trial found that there was no difference in 28 day survival between albumin and saline resuscitation for intensive care patients, and by providing very high quality data, this study has largely settled a generation old controversy. Intriguingly however, the SAFE study also reported that within a subgroup of 492 patients with TBI, 28 day survival was superior in patients receiving saline. This subgroup result was not considered definitive, but a post hoc examination of the TBI patients currently in progress by the SAFE investigators, is expected to provide further guidance for clinicians. In the meanwhile, and until more high quality data is available, many clinicians are likely to prefer crystalloid resuscitation for trauma patients, and especially for trauma patients with brain injury.

Cervical Spine Assessment in the Unconscious Trauma Patient: A Major Trauma Service???s Experience with Passive Flexion-Extension Radiography

BACKGROUND

There is no consensus on the most appropriate method of cervical spine assessment in unconscious trauma patients. Passive flexion-extension imaging is one option for further investigating unconscious patients whose plain cervical radiographs are normal. This study examines the usefulness of this passive imaging in investigating for occult cervical injury.

METHODS

All unconscious patients admitted to The Alfred Trauma Intensive Care Unit over 1 year (January 1-December 31, 1998), who could not be clinically assessed within 48 hours in regard to their cervical spine, were identified. Results of passive flexion-extension radiography were compared with final injury status and clinical outcome as determined by retrospective review of the imaging reports, radiographic films, and case notes.

RESULTS

One hundred twenty-three patients with normal three-view plain radiographs proceeded to passive functional investigation. These were false-negative in four of the seven patients with cervical spine injuries at presentation. No patients suffered any adverse neurologic events from their delayed diagnoses or from the flexion-extension procedure.

CONCLUSION

Passive flexion-extension imaging has inadequate sensitivity for detecting occult cervical spine injuries. Although no patients suffered adverse neurologic complications, the potential for devastating consequences from missed cervical injury has resulted in the removal of passive flexion-extension imaging from the screening protocol.

Prevalence of oral mucosal lesions in alcohol misusers in south London

BACKGROUND

Information on alcohol-associated oral mucosal lesions (OMLs) and conditions is meagre. A prevalence survey among alcohol misusers in south London was therefore undertaken.

METHODS

Six hundred and ninety-three subjects (388 alcohol misusers and 305 alcohol + substance abuse) attending several clinical care facilities in south London between 1994 and 1999 were interviewed on their alcohol and drug habits. A comprehensive oral mucosal examination was performed, and soft tissue lesions found were classified by the clinical criteria of Axéll.

RESULTS

Mean age of the sample was 40.5 years. The majority was white (92.6%); of the whites, 29.9% were Celts (i.e. Irish, Scots resident in London). Many subjects reported misusing more than one type of beverage. Two hundred and twenty-seven OMLs were found in 195 subjects (28.1%). The highest prevalences were found for frictional keratosis (8.8%), scar tissue of the lips (4.8%) and candidiasis (3.8%). Angular cheilitis was present in 21 subjects (3.0%). The alcohol-related OMLs detected were three white patches compatible with a diagnosis of leukoplakia and one treated oral carcinoma. No erythroplakias were detected. The differences in prevalence of mucosal lesions in the two groups were not significant (chi(2) = 2.18; P = 0.14). The prevalence of tobacco smoking was high in both study groups. OMLs were found with all four types of beverages consumed, and there was little variation by the units per week consumed. Concurrent use of substances and alcohol did not make a significant difference to the prevalence of OML. In the logistic regression analysis, minority ethnic groups (Black or Asian), smokers, those with a body mass index (BMI) under 20 and beer drinkers had an increased risk of an OML in this group of alcohol misusers.

CONCLUSIONS

In comparison with previous oral mucosal screening programmes undertaken in several settings in the UK, the present study has yielded a higher prevalence of oral mucosal diseases and conditions in this risk population. There are several ways in which alcohol could contribute to these detected oral lesions, either directly or indirectly.

Prehospital hypertonic saline resuscitation of patients with hypotension and severe traumatic brain injury: a randomized controlled trial

CONTEXT

Prehospital hypertonic saline (HTS) resuscitation of patients with traumatic brain injury (TBI) may increase survival but whether HTS improves neurological outcomes is unknown.

OBJECTIVE

To determine whether prehospital resuscitation with intravenous HTS improves long-term neurological outcome in patients with severe TBI compared with resuscitation with conventional fluids.

DESIGN, SETTING, AND PATIENTS

Double-blind, randomized controlled trial of 229 patients with TBI who were comatose (Glasgow Coma Scale score, <9) and hypotensive (systolic blood pressure, <100 mm Hg). The patients were enrolled between December 14, 1998, and April 9, 2002, in Melbourne, Australia.

INTERVENTIONS

Patients were randomly assigned to receive a rapid intravenous infusion of either 250 mL of 7.5% saline (n = 114) or 250 mL of Ringer's lactate solution (n = 115; controls) in addition to conventional intravenous fluid and resuscitation protocols administered by paramedics. Treatment allocation was concealed.

MAIN OUTCOME MEASURE

Neurological function at 6 months, measured by the extended Glasgow Outcome Score (GOSE).

RESULTS

Primary outcomes were obtained in 226 (99%) of 229 patients enrolled. Baseline characteristics of the groups were equivalent. At hospital admission, the mean serum sodium level was 149 mEq/L for HTS patients vs 141 mEq/L for controls (P<.001). The proportion of patients surviving to hospital discharge was similar in both groups (n = 63 [55%] for HTS group and n = 57 [50%] for controls; P =.32); at 6 months, survival rates were n = 62 (55%) in the HTS group and n = 53 (47%) in the control group (P =.23). At 6 months, the median (interquartile range) GOSE was 5 (3-6) in the HTS group vs 5 (5-6) in the control group (P =.45). There was no significant difference between the groups in favorable outcomes (moderate disability and good outcome survivors [GOSE of 5-8]) (risk ratio, 0.99; 95% confidence interval, 0.76-1.30; P =.96) or in any other measure of postinjury neurological function.

CONCLUSION

In this study, patients with hypotension and severe TBI who received prehospital resuscitation with HTS had almost identical neurological function 6 months after injury as patients who received conventional fluid.

Role of beer lipid-binding proteins in preventing lipid destabilization of foam

The negative effect of fatty acids on the foam stability of beer has been assessed. Long-chain fatty acids are far more damaging than short-chain fatty acids on the foam stability of beer at the concentrations employed. Polypeptides have been isolated from an all malt beer by hydrophobic interaction chromatography. Using this technique five groups of polypeptides were isolated, group 1 being the least hydrophobic and group 5 the most hydrophobic, all of which exhibited similar polypeptide compositions by SDS-PAGE. All five hydrophobic polypeptide groups bound [(14)C]linoleic acid; however, group 5, the most hydrophobic group, bound the most linoleic acid. Groups 1 and 5 were titrated with cis-parinaric acid (CPA) to produce binding curves, which were compared with a binding curve obtained for bovine serum albumin (BSA). Groups 1 and 5 both produced binding curves that saturated at approximately 5.5 microM and 4 microM CPA and had association constants (K(a)) of 6.27 x 10(7) and 1.62 x 10(7) M(-1), respectively. In comparison, BSA produced a binding curve that saturated at 6 microM CPA and had a K(a) of 3.95 x 10(7) M(-1). Further investigation has shown that group 1 is pH sensitive and group 5 pH insensitive with respect to lipid binding. The lipid-binding activity of group 5 was also shown to be unaffected by ethanol concentration. Linoleic acid (5 microM) when added to beer resulted in unstable foam. Group 5 was added to the lipid-damaged beer and was shown to restore the foam stability to values that were obtained for the control beer. It has therefore been demonstrated that proteins isolated from beer have a lipid-binding capacity and that they can convey a degree of protection against lipid-induced foam destabilization.

Oral manifestations of an HIV positive cohort in the era of highly active anti-retroviral therapy (HAART) in South London

BACKGROUND

Human Immunodeficiency Virus (HIV) infection is associated with oral manifestations of diagnostic and prognostic importance. With the advent of Highly Active Anti-retroviral Therapy (HAART) there is anecdotal evidence to suggest that the prevalence of oral lesions has declined. The number of prevalence studies, carried out in the era of HAART is, however, meagre. Our aim was to study the prevalence of the oral manifestations of HIV in a population, predominantly on HAART, attending a Genito-Urinary Medicine Centre in South London.

METHODS

This cross sectional study included 203 adult volunteers, comprising 76% males and 24% females. One third of the subjects were from the predominantly African or Afro- Caribbean ethnic minority groups resident in London. The relationship between the prevalence of oral lesions and demographic variables, therapeutic regimes, viral load and CD4 counts were evaluated.

RESULTS

One hundred (49%) of the patients had no detectable oral lesions. Oral lesions detected most frequently included oral hairy leukoplakia (9.9%), HIV associated periodontal diseases (9.9%) and oral candidiasis (4.9%). Three subjects had multiple papillomatous growths. Most cases (n = 17/20) of oral hairy leukoplakia were in individuals with a detectable (> 400 copies/ml) plasma RNA viral load. The majority (n = 8/10) of our patients with oral candidiasis had a plasma RNA viral load > 10,000 copies/ml and half (n = 5/10) had a CD4 count < 200 cells/mm3. Logistic regression analysis suggested that the presence of an oral lesion was not associated with any demographic features except for periodontal diseases which were associated with tobacco smoking (P = 0.023).

CONCLUSIONS

The prevalence of so called 'strongly associated' oral lesions of HIV is low in this South London HIV-infected population on HAART, and the relative frequency is different from that cited in the literature from the pre-HAART era. The oral lesions detected were found mostly in people with low CD4 counts and high HIV-1 RNA viral loads, suggesting they were very immunocompromised, not on, or declining therapy, or that their therapy was failing.

Factors contributing to fatal outcome of traumatic brain injury: a pilot case control study

OBJECTIVE

Patients with traumatic brain injury (TBI) have a high mortality and morbidity. This pilot study was undertaken to identify contributors to outcome in the early management of patients with TBI and to investigate the feasibility of a larger study.

METHODS

Road trauma patients who died between January 1 and April 30, 2000 were selected from the Alfred Hospital's Intensive Care Traumatic Brain Injury database. These patients were matched with 2 survivors from the data base during the same period for age, injury severity score (ISS) and severity of brain injury using the head abbreviated injury score (head AIS). Patient injury scoring (using the revised trauma score, trauma and injury severity score and Glasgow coma score), arterial blood gas analysis, lactate concentration, inspired oxygen concentration, systolic and mean arterial blood pressure, intracranial pressure, intravenous fluid and blood transfusion volumes, body temperature, haemoglobin, white cell count, INR, APTT, temperature and plasma glucose, urea and creatinine concentrations were recorded for 48 hours from the time of injury. Time periods from the accident to key events (e.g. arrival of ambulance at accident scene, intubation, arrival at the emergency department, insertion of intracranial pressure monitor and primary surgery) were also recorded.

RESULTS

Eighteen patients (6 deceased, 12 survivors) were identified. Despite matching, deceased patients had lower initial Glasgow Coma Scores (GCS) (3.6 vs. 7.4, P = 0.01) and lower revised trauma scores (4.41 vs. 5.75; P = 0.044) compared with survivors. There were no significant differences in other parameters. However, deceased patients tended to have longer times to treatment (P = NS) and experienced trauma at night more frequently, and survivors received almost double the volume of fluid resuscitation during the first 12 hours (19.7 +/- 19.1 vs. 11.8 +/- 2.7 mL/kg/hr, P = 0.513).

CONCLUSIONS

Both initial GCS and severity of brain injury should be used to match TBI patients for injury severity in future studies. Lower initial GCS in deceased patients was likely due to greater severity of brain injury, although it is also possible that the lower GCS was due to decreased brain perfusion (perhaps reflecting inadequate resuscitation) in these patients. Volume of early fluid resuscitation, time to definitive therapy, and time of presentation to hospital may also be important determinants of patient outcome. A large case control outcome study is required to extend these observations.

Time-division multiplexing of large serial fiber-optic Bragg grating sensor arrays

Time-division multiplexing is a promising method for the interrogation of fiber-optic Bragg grating sensors arrays for measurement of strain and temperature. We examine the performance of these systems to determine the parameters for high-sensitivity, low-cross-talk operation. It is shown that the performance can be greatly improved by use of a short time resolution in the demultiplexing process. We propose a new method of demultiplexing with an electro-optic modulator to read out the sensor pulses by gating the signal with 400-ps resolution. The system is demonstrated experimentally to provide 0.15-microepsilon/square root(Hz) strain resolution in a 50-Hz bandwidth within a full-scale range of 8000 microepsilon. The system parameters are capable of handling at least 50 time-addressed sensors on a single fiber.

Reed bed dewatering of agricultural sludges and slurries

In trials at Rugeley, UK, reed beds were used for dewatering agricultural sludges and slurries. Three beds, each of 3.5 m2, were employed, two planted with Phragmites australis, the third left unplanted as control. The sludge contained partly oxidised solids from a Biological Aerated Filter (BAF) treating weak pig slurry. It was supplemented with untreated settled pig slurry. Following reed establishment planted Bed A was fed at a constant similar rate to the unplanted Control Bed C. The second planted Bed B was fed at higher rates alternating with rest periods. On this bed the aeration pipes were blocked off. The trials were run for 16 months, which included two summer periods. The results showed that the planted Bed A had definitely better dewatering ability than the unplanted one fed at a similar rate. During the summer months Bed B could be fed at over twice the rate used for the constant input beds. The percolate from the control bed was more highly oxidised than from the planted beds, probably due to a longer holdup time in the absence of reeds. On Bed B the reed quality deteriorated during the second year, after use of untreated slurry as feed.

Percutaneous tracheostomy in critically ill patients: a prospective, randomized comparison of two techniques

OBJECTIVE

To prospectively compare two commonly used methods for percutaneous dilational tracheostomy (PDT) in critically ill patients.

DESIGN

Prospective, randomized, clinical trial.

SETTING

Trauma and general intensive care units of a university tertiary teaching hospital, which is also a level 1 trauma center.

PATIENTS

One hundred critically ill patients with an indication for PDT.

INTERVENTIONS

PDT with the Ciaglia technique using the Ciaglia PDT introducer set and the Griggs technique using a Griggs PDT kit and guidewire dilating forceps.

MEASUREMENTS AND MAIN RESULTS

Surgical time, difficulties, and surgical and anesthesia complications were measured at 0-2 hrs, 24 hrs, and 7 days postprocedure. Groups were well matched, and there were no differences between the two methods in surgical time or in anesthesia complications. Major bleeding complications were 4.4 times more frequent with the Griggs PDT kit. With the Ciaglia PDT kit, both intraoperative and at 2 and 24 hrs, surgical complications were less common (p = .023) and the procedure was more often completed without expert assistance (p = .013). Tracheostomy bleeding was not associated with either anticoagulant therapy or an abnormal clotting profile. Multivariate analysis identified the predictors of PDT complications as the Griggs PDT kit (p = .027) and the Acute Physiology and Chronic Health Evaluation (APACHE) II score (p = .041). The significant predictors of time required to complete PDT were the APACHE II score (p = .041), a less experienced operator (p = .0001), and a female patient (p = .013).

CONCLUSIONS

Patients experiencing PDT with the Ciaglia PDT kit had a lower surgical complication rate (2% vs. 25%), less operative and postoperative bleeding, and less overall technical difficulties than did patients undergoing PDT with the Griggs PDT kit. Ciaglia PDT is, therefore, the preferred technique for percutaneous tracheostomy in critically ill patients.

Massive baclofen overdose

A case is presented of a massive baclofen overdose with the highest blood baclofen concentrations currently reported. Interesting clinical features included profound hypotension, distributive shock and absent brainstem reflexes. Cerebral recovery was surprisingly slow but complete, and was then unexpectedly terminated by a sudden major splenic arterial haemorrhage followed by a severe haemorrhage of the aorta which proved to be due to cystic medial necrosis. This arterial anatomic abnormality and cause of death may have been coincidental, or may instead be a previously unreported complication of massive baclofen toxicity.

Early diagnosis of traumatic aortic valve rupture in ICU patients using transoesophageal echocardiography

A case is presented of a 60-year-old man who sustained spinal and chest wall injuries following a collision between his glider and an aeroplane. The severity of his injuries required him to be managed with bilateral underwater seal drains, cervical spine stabilisation and sedation with mechanical ventilation. Due to the severity of his chest trauma, a transoesophageal echocardiograph was performed which revealed a partial dehiscence and prolapse of the left coronary cusp of the aortic valve with mild to moderate aortic regurgitation. Despite conservative treatment, severe cardiac failure developed six days later requiring aortic valve replacement. After a prolonged stay in the Intensive Care Unit during which the patient developed acute respiratory distress syndrome, methicillin resistant Staphylococcus aureus pneumonia and Enterobacter septicaemia, the patient was discharged, returning to his pre-admission lifestyle. In patients with complex and severe chest trauma, transoesophageal echocardiography is of great benefit, not only in allowing good image quality, compared with transthoracic echocardiography, but having a greater reliability and accuracy in diagnosing cardiac and mediastinal trauma in complex monitoring environments.

Novel octaketide macrolides related to 6-deoxyerythronolide B provide evidence for iterative operation of the erythromycin polyketide synthase

BACKGROUND

The macrolide antibiotic erythromycin A, like other complex aliphatic polyketides, is synthesised by a bacterial modular polyketide synthase (PKS). Such PKSs, in contrast to other fatty acid and polyketide synthases which work iteratively, contain a separate set or module of enzyme activities for each successive cycle of polyketide chain extension, and the number and type of modules together determine the structure of the polyketide product. Thus, the six extension modules of the erythromycin PKS (DEBS) together catalyse the production of the specific heptaketide 6-deoxyerythronolide B.

RESULTS

A mutant strain of the erythromycin producer Saccharopolyspora erythraea, which accumulates the aglycone intermediate erythronolide B, was found unexpectedly to produce two novel octaketides, both 16-membered macrolides. These compounds were detectable in fermentation broths of wild-type S. erythraea, but not in a strain from which the DEBS genes had been specifically deleted. From their structures, both of these octaketides appear to be aberrant products of DEBS in which module 4 has 'stuttered', that is, has catalysed two successive cycles of chain extension.

CONCLUSIONS

The isolation of novel DEBS-derived octaketides provides the first evidence that an extension module in a modular PKS has the potential to catalyse iterative rounds of chain elongation like other type I FAS and PKS systems. The factors governing the extent of such 'stuttering' remain to be determined.

Hypertonic saline resuscitation for head injured patients

OBJECTIVE

To discuss the reasons why 250 ml 7.5% hypertonic saline was chosen as a pre-hospital resuscitation fluid for head injured patients in a multicentred, prospective, randomised controlled trial investigating its long term effects on central nervous system outcome.

DATA SOURCES

Recent published peer-review articles on the incidence and mechanisms of traumatic head injury and clinical use of hypertonic saline in pre-hospital resuscitation of trauma.

SUMMARY OF REVIEW

Head injury is commonly associated with major trauma and if hypotension also exists the morbidity and mortality due to cerebral injury are high. Hypertonic saline has been used in clinical practice to treat cerebral oedema and resuscitate burns patients following experimental evidence that it reduces tissue oedema, improves blood flow to damaged organs and may reduce the incidence of multiple organ dysfunction, when compared with resuscitation using isotonic solutions. In pre-hospital trauma patients, initial resuscitation using hypertonic saline rather than conventional isotonic solutions has the potential advantage of requiring a small volume of fluid that is easily stored and administered, and may improve cerebral circulation and reduce the long term neurological effects that are determined by pre-hospital hypovolaemia and hypotension. To answer the question whether hypertonic saline will improve the outcome in trauma patients with hypotension and head injury, a multicentred, randomised controlled trial comparing 250 ml of 7.5% hypertonic saline (320 mmol) with 250 ml of Hartmann's solution (32 mmol) in pre-hospital resuscitation of trauma patients with a Glasgow coma score < 9 and systolic blood pressure < 100 mmHg, began in 1998 and is anticipated to be completed by 2001.

CONCLUSIONS

Pre-hospital resuscitation of head injured and hypotensive trauma patients using hypertonic saline, has the potential to reduce long term cerebral injury and reduce social and financial costs to the community.

Management of severe trauma in intensive care units and surgical wards

OBJECTIVE

To evaluate the management of severe trauma in intensive care, high dependency and general surgical wards of Victorian hospitals.

DESIGN

Retrospective case review by multidisciplinary committees.

SUBJECTS

The first 256 people who died from road traffic accidents who were alive on the arrival of emergency services between 1 July 1992 and 30 June 1994.

MAIN OUTCOME MEASURES

(1) Severity of injury according to clinical diagnosis, autopsy findings and recognised trauma-scoring methods; (2) errors in management, identified as contributing or not contributing to the cause of death, and categorised as "management", "system", "diagnostic" or "technique" errors.

RESULTS

Most patients (61%) were admitted to an intensive care unit (ICU), and 19.5% were admitted to high dependency or general surgical wards. Of 2187 errors of care identified, 11.8% occurred in ICU and 6.7% in wards, with the remainder occurring during the earlier phases of care. Most errors were classified as management errors (82% of ICU errors and 88% of ward errors). Fifty-two per cent of ICU errors and 71% of ward errors were judged to contribute to the patient's death.

CONCLUSIONS

A significant number of errors of trauma management occur in the intensive care and general surgical ward. Improvement in late trauma care may reduce the number of preventable trauma deaths.

Hyperbaric or normobaric oxygen for acute carbon monoxide poisoning: a randomised controlled clinical trial

OBJECTIVE

To assess neurological sequelae in patients with all grades of carbon monoxide (CO) poisoning after treatment with hyperbaric oxygen (HBO) and normobaric oxygen (NBO).

DESIGN

Randomised controlled double-blind trial, including an extended series of neuropsychological tests and sham treatments in a multiplace hyperbaric chamber for patients treated with NBO.

SETTING

The multiplace hyperbaric chamber at the Alfred Hospital, a university-attached quarternary referral centre in Melbourne providing the only hyperbaric service in the State of Victoria.

PATIENTS

All patients referred with CO poisoning between 1 September 1993 and 30 December 1995, irrespective of severity of poisoning. Pregnant women, children, burns victims and those refusing consent were excluded.

INTERVENTION

Daily 100-minute treatments with 100% oxygen in a hyperbaric chamber--60 minutes at 2.8 atmospheres absolute for the HBO group and at 1.0 atmosphere absolute for the NBO group--for three days (or for six days for patients who were clinically abnormal or had poor neuropsychological outcome after three treatments). Both groups received continuous high flow oxygen between treatments.

MAIN OUTCOME MEASURES

Neuropsychological performance at completion of treatment, and at one month where possible.

RESULTS

More patients in the HBO group required additional treatments (28% v. 15%, P = 0.01 for all patients; 35% v. 13%, P = 0.001 for severely poisoned patients). HBO patients had a worse outcome in the learning test at completion of treatment (P = 0.01 for all patients; P = 0.005 for severely poisoned patients) and a greater number of abnormal test results at completion of treatment (P = 0.02 for all patients; P = 0.008 for severely poisoned patients). A greater percentage of severely poisoned patients in the HBO group had a poor outcome at completion of treatment (P = 0.03). Delayed neurological sequelae were restricted to HBO patients (P = 0.03). No outcome measure was worse in the NBO group.

CONCLUSION

In this trial, in which both groups received high doses of oxygen, HBO therapy did not benefit, and may have worsened, the outcome. We cannot recommend its use in CO poisoning.

Quality assessment of the management of road traffic fatalities at a level I trauma center compared with other hospitals in Victoria, Australia. Consultative Committee on Road Traffic Fatalities in Victoria

OBJECTIVES

Since 1992, the Consultative Committee on Road Traffic Fatalities in Victoria, Australia, has identified problems including those contributing to death and the potential preventability of deaths in road fatalities who survived until at least the arrival of ambulance services. The present analysis examines the outcomes at a Level I trauma center compared with other hospital groups in Victoria.

METHODS

Between 1992 and 1994, 257 consecutive eligible fatalities were evaluated. Problems in management and preventable deaths were identified at the trauma center (TC) and in pooled data from other hospital groups, i.e., specialist teaching (Level II), other metropolitan (Level III), large regional (Level III), and small regional hospitals.

RESULTS

Mean problems identified and those contributing to death (controlled for the number of areas of care), were less frequent at TC (1.7 and 0.6) than at other hospital groups (specialist teaching, 1.9 and 1.1*; metropolitan, 3.1* and 1.6*; large regional, 3.8* and 1.8*; small regional, 5.1* and 2.6*) (*p < 0.05 compared with TC). Preventable and potentially preventable deaths were also less common at TC (20%) than at the other hospital groups (specialist teaching, 40%*; metropolitan, 41%*; large regional, 53%*; small regional, 62%*) (*p < 0.05 compared with TC). When a Trauma and Injury Severity Score of 75% or more was used to define preventable death, a similar trend was identified.

CONCLUSION

Management of patients with major trauma at a Level I trauma center was associated with fewer problems contributing to death and fewer preventable and potentially preventable deaths than at the different hospital groups. A trauma system in Victoria, including bypass of major trauma patients to designated hospitals with 24-hour trauma services, is likely to decrease the frequency of problems, including the preventable death rates.

Optimal assessment of cervical spine trauma in critically ill patients: a prospective evaluation

There is no uniformly accepted protocol for the radiological assessment of the cervical spine in critically ill trauma patients. The Alfred Trauma Centre receives about 40% of Victorian patients with major trauma. A protocol was developed for cervical spine evaluation, comprising three plain X-rays and a swimmer's view added when necessary to visualize C7-T1, CT and/or MRI for abnormal regions, and functional (flexion/extension) X-rays to exclude cervical spine instability due to soft tissue trauma. Functional X-rays were performed "actively" in conscious patients and "passively" in unconscious patients. One hundred consecutive patients were prospectively evaluated and 91 survived to complete data collection. Six (6.6%) had unstable cervical spine injuries--five detected with plain X-rays and one (1.1%) detected only with passive functional X-rays. Static cervical X-rays cost $93.00 per patient. Functional cervical X-rays added $42.00 per patient and were uncomplicated. Collar complications were common when collars remained on for more than 72 hours. This low detection rate is clinically important because of the enormous potential social and economic costs of missed unstable cervical spine fractures.

The effect of manual lung hyperinflation and postural drainage on pulmonary complications in mechanically ventilated trauma patients

This study questioned whether manual lung hyperinflation (MHI) and postural drainage reduced the incidence of nosocomial pneumonia or improved other outcome variables in mechanically ventilated trauma patients. Patients were withdrawn from the study if they developed nosocomial pneumonia according to a predetermined definition or on the clinical suspicion of nosocomial pneumonia by the attending intensivist. Of the 46 patients who fulfilled all the inclusion criteria and were enrolled into the study, 22 patients were randomized to group A (physiotherapy) and 24 patients to group B (control group). Twice as many patients were withdrawn in group B (8/24) compared with group A (4/22), although the differences were not statistically significant, [X2(1, 1) = 1.36, P = 0.24]. The length of time receiving mechanical ventilation and in the ICU was similar between the two groups and there were no differences in pulmonary dysfunction ("worst" daily PaO2/FiO2 ratio) between the two groups. There were no ICU deaths in either group. Physiotherapy as used in this study was not associated with a reduced incidence of nosocomial pneumonia based on standard clinical criteria. Nevertheless the trend to more frequent nosocomial pneumonia in the control patients suggests that a larger study in more severely injured patients with stricter clinical criteria for the definition of nosocomial pneumonia is indicated.