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Biomedical subjects

C E Robertson

Publications and source records attributed to C E Robertson.

At least 19 recordsLinked to original sources
PubMed2005

Practical issues in the evaluation of methods for the prediction of shock outcome success in out-of-hospital cardiac arrest patients.

There is a need for robust, effective predictors of the outcome from shock for out-of-hospital cardiac arrest patients. Such technology would enable the emergency responder to provide a therapy tailored to the patient's needs. Here we report our most recent findings while dwelling intentionally on the rationale behind the decisions taken during system development. Specifically, we illustrate the need for sensible data selection, fully cross-validated results and the care necessary when evaluating system performance. We analyze 878 pre-shock ECG traces, all of at least 10 s duration from 110 patients with cardiac arrest of cardiac aetiology. The continuous wavelet transform was applied to preshock segments of ECG trace. Time-frequency markers are extracted from the transform and a linear threshold derived from a training set to provide high sensitivity prediction of successful defibrillation. These systems are then evaluated on a withheld test set. All experiments are cross-validated. When compared to popular Fourier-based techniques our wavelet transform method, COP (Cardioversion Outcome Predictor), provides a 10-20% improvement in performance with values of 66 +/- 4 specificity at 95 +/- 4 sensitivity, 61 +/- 4 specificity at 97 +/- 2 sensitivity and 56 +/- 1 specificity at 98 +/- 2 sensitivity achieved for datasets limited to 3, 6, and 9 shocks per patient, respectively. Thus, the assessment of the wavelet marker was associated with a high specificity value at or above 95% sensitivity in comparison to previously reported methods. Therefore, COP could provide an optimal index for the identification of patients for whom shocking would be futile, and for whom an alternative therapy could be considered.

Animals↗
PubMed2005

Prospective audit of 106 consecutive human bite injuries: the importance of history taking.

OBJECTIVES: Some patients attempt to conceal human bites with factitious mechanisms of injury. Follow up questioning allows patients to modify their histories. This practice was prospectively audited. METHODS: Patients with cutaneous wounds who did not present with a history of human bite were asked a follow up question. Those who then gave a history of human bite were noted. RESULTS: Certain groups of patients with human bites were significantly more likely to provide a factitious history and/or delay presentation. CONCLUSION: Follow up questioning dramatically increased the case-detection rate, prompting specific management.

Adolescent↗
PubMed2005

An audit of clinical practice in the management of head injured patients following the introduction of the Scottish Intercollegiate Guidelines Network (SIGN) recommendations.

A prospective study was conducted by the Scottish Trauma Audit Group (STAG) in A&E of Edinburgh Royal Infirmary to examine clinical practices in the management of head injured patients pre- and post-inception of the SIGN guidelines published in August 2000.1607 patients attended the department in two separate one month periods at equal intervals pre- and post-guidelines publication. The majority of patients with a SIGN indication for admission were admitted (93% pre- and 92% post-guidelines). For skull x ray (SXR) requests, in the pre-guidelines group, 92% of admitted patients with a SIGN indication for x ray had a SXR: this figure dropped to 79% post-guidelines. 36% of patients with a SIGN indication for CT actually had a scan pre-guidelines: this figure increased to 64% post-guidelines.57% of patients pre-guidelines and 44% of patients post-guidelines were discharged from A&E in accordance with the SIGN recommendations. Of patients admitted for neurological observations, this increased from 50% pre- to 88% post-guidelines. Of patients who were discharged "inappropriately", only one re-presented and was subsequently admitted but required no neurosurgical intervention. Despite publication of the SIGN guidelines and positive reinforcement in A&E and at ward level, practice has not changed significantly. Where our practice did not adhere to SIGN recommendations, there was no untoward sequelae. For published national guidelines to be effective, a formal audit structure with regular feedback is necessary to ensure a continued change in clinical practices.

Craniocerebral Trauma↗
PubMed2002

Thrombolysis and its implications in the management of stroke in the accident and emergency department.

OBJECTIVES: Examination of initial management of stroke patients in the emergency setting to assess feasibility of thrombolysis for acute ischaemic stroke. METHODS: Retrospective analysis of all patients presenting with a clinical diagnosis of stroke over a two month period. Exclusion criteria for thrombolysis were applied to assess the number of patients that would potentially have been eligible for thrombolysis. RESULTS: Of 94 patients identified with clinical stroke, only 57 (60.6%) had a CT scan; 23 (24.4%) were confirmed as having had an acute ischaemic stroke. Mean delay in scanning was 2.2 days (range 0-15 days). Even if all patients had presented and been scanned within three hours (as required for thrombolysis), only six (6.4%) patients would have been eligible for thrombolysis. CONCLUSIONS: The great majority of patients presenting with clinical stroke do not fulfill the criteria for thrombolysis. Current practice involves significant delays in CT scanning, which has implications for resource structuring should thrombolysis become widely available.

Adult↗
PubMed2000

A novel wavelet transform based analysis reveals hidden structure in ventricular fibrillation.

We report a new method of interrogating the surface ECG signal using techniques developed in the field of wavelet transform analysis. Previously unreported structure within the ECG during ventricular fibrillation (VF) is found using a high-resolution decomposition of the signal employing the continuous wavelet transform. We believe that wavelet transform methods could lead to the development of powerful tools for use in the resuscitation of patients with cardiac arrest.

Animals↗
PubMed2000

Paramedic activities, drug administration and survival from out of hospital cardiac arrest.

OBJECTIVE: To examine the impact of administration of cardioactive drugs on the outcome from out of hospital cardiac arrest. DESIGN: Longitudinal observational cohort study with historical controls before and after the introduction of drug use in cardiac arrest by paramedics. SUBJECTS: Adult patients who had sustained an out of hospital cardiac arrest of cardiac aetiology and were treated by paramedics. SETTING: Edinburgh, Scotland. OUTCOME MEASURES: Return of spontaneous circulation, admission to and discharge from hospital. RESULTS: There was no significant difference in the demographics between Period 1 (prior to drug administration) and Period 2 (after). There was no difference in outcome between Period 1 and Period 2 for all three parameters, return of spontaneous output 30.1 versus 35%, admission to hospital 18.9 versus 24.5% and discharge 5.8 versus 6.5%. If the presenting rhythm of VF/pulseless VT alone was considered survival to hospital discharge was 12.1% in Period 1 and 10.3% in Period 2. CONCLUSION: The addition of cardioactive drug administration to the treatment of out of hospital cardiac arrest does not improve survival.

Adult↗
PubMed1999

Initial serum ferritin levels in patients with multiple trauma and the subsequent development of acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) represents a catastrophic form of inflammatory lung injury that occurs unpredictably in some, but not all, at-risk patients. In this study, we investigated serum ferritin as a marker for ARDS development in a homogenous group of patients at-risk because of multiple trauma. We hypothesized that since ferritin synthesis is increased by proinflammatory cytokines, which are increased and implicated in ARDS, that ferritin levels would increase and that ferritin increases would correlate with the degree of inflammation and therefore the development of ARDS. We studied 42 patients (25 male, 17 female) who as a consequence of multiple trauma became at-risk for developing ARDS. Using the European/American Consensus definition for ARDS, 16 (38%) patients subsequently developed ARDS (11 male and five female). We found that initial serum ferritin levels correlated with the subsequent development of both ARDS (progression to ARDS, median = 638 ng/ml; (range, 70 to 4,500) versus nonprogression to ARDS = 185 ng/ml; range, 12 to 2,850) (p = 0.02, r = -0.27) and multiple organ failure (p < 0.05, r = 0.39). Using our previously established cutoff points for serum ferritin, the positive predictive value was 62% for men and 75% for women. Initial serum ferritin levels also correlated with a measurement of the degree of initial trauma injury, i.e., the injury severity score (ISS) (p < 0.05, r = 0.37). However, there was no correlation between serum ferritin levels and other markers of clinical injury, namely, lowest PaO2/FIO2 ratio (p = 0.67), days requiring ventilation (p = 0.09), or mortality (p = 0.42). A significant association existed between serum ferritin levels and products of endothelial activation, i.e., sE-selectin (p < 0.04, r = 0.37) and sICAM-1 (p < 0.01, r = 0.21). In the future, with the development of novel anti-inflammatory therapies, early identification of specific high-risk patients would allow the institution of these therapies and thereby increase the chances of reducing ARDS morbidity and mortality.

Acute Disease↗
PubMed1998

Advanced life support for out-of-hospital cardiac arrest--the changing role of a hospital-based flying squad.

The success of hospital-based flying squads in the management of out-of-hospital cardiac arrest has been well documented, but since the introduction of ambulance paramedics the need for such teams to deal with cardiac arrests has been questioned. We performed a 3-year retrospective study of non-traumatic arrests attended by Medic 1, the flying squad based at the Royal Infirmary of Edinburgh. There were 99 males and 46 females, mean age 57.6 years (range 17-86 years). Seventy-eight (53.9%) patients were pronounced dead at scene, 47 patients (32.4%) were admitted to hospital and 20 (13.7%) survived to hospital discharge. All but two of the survivors had return of spontaneous circulation prior to the arrival of Medic 1. Accident flying squads operating as a secondary response unit to victims of non-traumatic cardiac arrest are unlikely to have a significant effect upon overall survival.

Adolescent↗
PubMed1997

Comparison of two emergency response systems and their effect on survival from out of hospital cardiac arrest.

The pre-hospital care provided by emergency response systems will have an effect on the outcome of patients who have sustained an out of hospital cardiac arrest. This study compares the results of resuscitation in two centres, one in the UK (Edinburgh) and the other in the USA (Milwaukee), and examines the demographics in both centres. An overall greater proportion of patients survived to hospital discharge in Edinburgh, 12.4%, compared with 7.2% in Milwaukee (P < 0.01). However patients were more likely to have a witnessed collapse in Edinburgh 65.7%, compared with 25% (P < 0.001) and significantly more of those patients received bystander cardiopulmonary resuscitation (CPR) 42.3%, compared with 27.1% (P < 0.005). When these two effects are accounted for there is no difference in outcome. The importance of early alerting of emergency services and early bystander CPR should not be underestimated.

Cardiopulmonary Resuscitation↗
PubMed1997

Can the full range of paramedic skills improve survival from out of hospital cardiac arrests?

OBJECTIVE: To examine the effect of full implementation of advanced skills by ambulance personnel on the outcome from out of hospital cardiac arrest. SETTING: Patients with cardiac arrest treated at the accident and emergency department of the Royal Infirmary of Edinburgh. METHODS: All cardiorespiratory arrests occurring in the community were studied over a one year period. For patients arresting before the arrival of an ambulance crew, outcome of 92 patients treated by emergency medical technicians equipped with defibrillators was compared with that of 155 treated by paramedic crews. The proportions of patients whose arrest was witnessed by lay persons and those that had bystander cardiopulmonary resuscitation (CPR) were similar in both groups. RESULTS: There was no difference in the presenting rhythm between the two groups. Eight of the 92 patients (8.7%) treated by technicians survived to discharge compared with eight of 155 (5.2%) treated by paramedics (NS). Of those in ventricular fibrillation or pulseless ventricular tachycardia, eight of 43 (18.6%) in the technician group and seven of 80 (8.8%) in the paramedic group survived to hospital discharge (NS). For patients arresting in the presence of an ambulance crew, four of 13 patients treated by technicians compared with seven of 15 by paramedics survived to hospital discharge. Only two patients surviving to hospital discharge received drug treatment before the return of spontaneous circulation. CONCLUSIONS: No improvement in survival was demonstrated with more advanced prehospital care.

Adult↗
PubMed1996

Rate, causes and prevention of deaths from injuries in south-east Scotland.

Data on all deaths after injuries in Lothian and Borders regions of south-east Scotland were collected prospectively over 2 years. Post-mortems were performed after all deaths and Injury Severity Scores (ISS) calculated. There were 331 deaths at a rate of 20 per 100,000 per year; of those who died 49 per cent were younger than 40 years and most were male; 37 per cent of deaths were caused by road traffic accidents, 16 per cent by falls and 15 per cent by hangings. Two hundred and forty-eight patients (75 per cent) were either dead when found or died instantly with unsurvivable injuries (ISS = 75). A further five patients died in the first hour after injury and before reaching hospital. Nineteen (7 per cent) died between 1 and 4 h after injury, 59 (17 per cent) died more than 4 h after. These results demonstrate the rate, causes and timing of deaths following injuries in one UK region. The pattern of these deaths differs markedly from that previously described in the US. There is no evidence to support the concept of a trimodal distribution of trauma deaths. The greatest potential to reduce the number of trauma deaths lies with prevention.

Accident Prevention↗
PubMed1996

Transthoracic defibrillation: importance of avoiding electrode placement directly on the female breast.

OBJECTIVES: This study sought to determine the effect on transthoracic impedance of placement of defibrillation electrodes on the female breast versus adjacent to or under the breast. BACKGROUND: Transthoracic impedance is a major determinant of transthoracic current flow in defibrillation. For a given energy setting, a high transthoracic impedance reduces current flow and may adversely affect the ability of electric shocks to accomplish defibrillation. We hypothesized that the increased interelectrode tissue associated with placement of the apex defibrillation electrode on the female breast would result in increased transthoracic impedance compared with electrode placement lateral to or under the breast. METHOD: Transthoracic impedance was measured noninvasively by passing a 5-V, 31.25-kHz square wave current through the chest and comparing the low level current flow to known references. We measured transthoracic impedance associated with three different apex defibrillation electrode positions--on the breast, under the breast and lateral to the breast--in 25 women (brassiere size 34A to 48C, 25 to 75 years old, body weight 128 to 328 lb [58 to 148 kg] and 2 men. The measurements were taken with a modified defibrillator that accurately predicts transthoracic impedance without delivering an actual shock. The measurement sequence was random. RESULTS: The average measured transthoracic impedance with placement of the apex defibrillation electrode on the breast was 95 +/- 25 ohms (mean +/- SD), under the breast 84 +/- 17* ohms and lateral to the breast 83 +/- 20* ohms (asterisk indicates p < 0.01 vs. on the breast by analysis of variance). The study cohort was also classified into two groups: large breasted (brassiere size > or = 40) and small breasted (brassiere size < or = 39). The measured transthoracic impedances for the large-breasted group were 112 +/- 20 ohms for on the breast, 94 +/- 13* ohms for under the breast and 98 +/- 19* ohms for lateral to the breast. For the small breasted group, the similar transthoracic impedance measurements were 81 +/- 21, 77 +/- 16 and 71 +/- 13* ohms, respectively. CONCLUSIONS: In women, placement of the apex defibrillation electrode on the breast results in higher transthoracic impedance, which will reduce current flow. We recommend placing the apex electrode lateral to or underneath the breast.

Adult↗
PubMed1996

The effect of ward design on the well-being of post-operative patients.

Changes in the design of hospital wards have usually been determined by architects and members of the nursing and medical professions; the views and preferences of patients have seldom been sought directly. The Hospital Anxiety and Depression scale and the Disturbance Due to Hospital Noise questionnaire were administered to 64 female patients on bay and Nightingale wards together with a questionnaire designed for this study. Perceptions of social and physical factors of ward design were examined, and their relationship to psychological well-being and sleep patterns. The results show that the bay ward seemed to offer a more favourable environment for patients but some of the disadvantages of bay wards are balanced by better staffing levels and better and more modern facilities. Visibility to nurses was lower on the bay ward. The Nightingale ward was perceived as significantly noisier than the bay ward and noise levels were significantly correlated to anxiety scores. Paradoxically the increase in noise levels appeared to improve the perceived level of privacy on the Nightingale ward. Seventy-five per cent of patients were found to prefer the bay ward design, and since neither design appears to have major disadvantages their continued introduction should be encouraged. However, recommendations are made concerning the optimizing of patients' well-being within the bay ward setting.

Adult↗
PubMed1996

Adrenaline, cardiac arrest, and evidence based medicine.

In this article we review the evidence supporting the clinical application of adrenaline in cardiopulmonary arrest, and summarize the receptor effects of catecholamines and the basic principles producing perfusion during CPR. Animal and human studies show that in cardiac arrest, adrenaline has positive haemodynamic effects, increasing systemic pressures, myocardial perfusion, and cerebrally directed flow. The problems extrapolating from animal to human data are highlighted. Studies showing improvements in short term survival outcomes with high dose regimens have not been confirmed by other large prospective randomised trials. There is no evidence that high doses of adrenaline improve survival to hospital discharge. Most studies comparing adrenaline with placebo have been non-randomised and uncontrolled, with major methodological problems. Conclusions are difficult, but if anything adrenaline is associated with poorer outcomes.

Adrenergic Agonists↗
PubMed1995

Paramedics and technicians are equally successful at managing cardiac arrest outside hospital.

OBJECTIVE: To examine the effect on survival of treatment by ambulance paramedics and ambulance technicians after cardiac arrest outside hospital. DESIGN: Prospective study over two years from 1 April 1992 to 31 March 1994. SETTING: Accident and emergency department of university teaching hospital. SUBJECTS: 502 consecutive adult patients with out of hospital cardiopulmonary arrest of cardiac origin. INTERVENTIONS: Treatment by ambulance technicians or paramedics both equipped with semiautomatic defibrillators. MAIN OUTCOME MEASURES: Rate of return of spontaneous circulation, hospital admission, and survival to hospital discharge. RESULTS: Rates of return of spontaneous circulation, hospital admission, and survival to hospital discharge were not significantly different for patients treated by paramedics as opposed to ambulance technicians. Paramedics spent significantly longer at the scene of the arrest than technicians (P < 0.0001). CONCLUSIONS: The response of ambulance paramedics to patients with cardiopulmonary arrest outside hospital does not provide improved outcome when compared with ambulance technicians using basic techniques and equipped with semi-automatic defibrillators.

Adult↗