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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

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

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

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

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

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

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

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

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

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

Evaluation of outcome following cardiac arrest in patients presenting to two Scottish emergency departments.

OBJECTIVES: To compare and contrast outcomes following cardiac arrest managed in two Accident and Emergency departments, and to identify factors which might account for such differences. DESIGN: Prospective 1-year evaluation of patients sustaining an out-of-hospital cardiac arrest. SETTING: The Accident and Emergency departments of the Edinburgh (ERI) and Glasgow (GRI) Royal Infirmaries which serve two large urban municipalities. PATIENTS: All patients sustaining a prehospital cardiac arrest and brought to ERI or GRI were included. Children (< 13 years), those declared dead on arrival at the scene, and events related to poisoning, near drowning, trauma and pregnancy were excluded. MEASUREMENTS AND MAIN RESULTS: There were 297 prehospital arrests from ERI, and 158 from GRI. Eighty-two (27.6%) were admitted as 'in-patients' to ERI and 23 (14.6%) to GRI (P < 0.01). Thirty-nine (13.1%) survived to hospital discharge from ERI; 13 (8.2%) survived to discharge from GRI (NS). The proportion of VF/VT:Asystole observed was significantly different between the two centres--162:98 from ERI, 54:73 from GRI (P < 0.001). Significantly more prehospital arrests were witnessed and received bystander CPR in those brought to ERI (P < 0.02). For the combined VF/VT/Asystole groups the ERI ambulance response times were significantly shorter (P < 0.01). However, there was no significant difference in the collapse to EMS arrival at the scene times between ERI and GRI. Two survivors from ERI had asystole as their initial observed rhythm. From GRI, one survivor had asystole, one had electromechanical dissociation and in another the initial rhythm was unknown. No survivor to discharge had severe neurological disability. CONCLUSIONS: Patients suffering out-of-hospital cardiac arrests in Edinburgh have a significantly better chance of being admitted to a ward. There is a trend favouring better survival to discharge in Edinburgh, but with the numbers investigated this does not achieve statistical significance. Amongst those factors which contribute to survival there are fewer witnessed arrests, less bystander CPR and slower ambulance response times in those brought to GRI. There is a need to investigate the environment in which patients collapse, to train the public in CPR, and to review the efficiency and resourcing of the ambulance service.

Adolescent

Active decompression improves the haemodynamic state during cardiopulmonary resuscitation.

OBJECTIVE: To examine whether use of the active compression-decompression device improves the haemodynamics of cardiopulmonary resuscitation compared with those of conventional cardiopulmonary resuscitation. DESIGN: Prospective crossover study. SETTING: The accident and emergency department of a university teaching hospital. PATIENTS: 36 adult patients with non-traumatic, normothermic, out of hospital cardiac arrest. INTERVENTIONS: Cardiopulmonary resuscitation was performed during resuscitation in alternating 3 min cycles of conventional and active compression-decompression cardiopulmonary resuscitation. MAIN OUTCOME MEASURES: The end tidal carbon dioxide (ETCO2), femoral arterial pressure, and acid-base analysis of central venous blood measured during the last 30 s of each 3 minute cardiopulmonary resuscitation cycle. RESULTS: ETCO2 was monitored in 36 patients during conventional and active compression-decompression cardiopulmonary resuscitation. Active compression-decompression cardiopulmonary resuscitation caused a significant increase in ETCO2 (P < 0.0002), indicating improved cardiac output. Arterial pressure measurement was carried out in 10 patients. Systolic pressure was significantly greater with active compression-decompression than conventional cardiopulmonary resuscitation (P < 0.007). Central venous blood was taken for acid-base analysis in 11 patients. There was a significant increase in the central venous hydrogen ion concentration (P = 0.025) with rises in the partial pressures of carbon dioxide and oxygen, suggesting improved venous return. CONCLUSIONS: This study confirms that active compression-decompression cardiopulmonary resuscitation is associated with better haemodynamic status than conventional resuscitation.

Acid-Base Equilibrium

Plasma elastase levels and the development of the adult respiratory distress syndrome.

Inflammatory cells, particularly neutrophil granulocytes, have been implicated in the pathogenesis of the adult respiratory distress syndrome (ARDS). In this study, we investigated whether a relationship exists between neutrophil elastase in the plasma of multiple-trauma patients on initial hospital presentation and the subsequent development of lung injury and ARDS. Sixty-one multiple-trauma patients were enrolled prospectively. Neutrophil elastase was measured by a specific radioimmunoassay, and analysis was performed by nonparametric statistical methods. A highly significantly elevated plasma elastase level was found in patients who progressed to ARDS (median 217 ng/ml, range 127 to 480) (n = 8) compared with those who did not (median 117 ng/ml, range 21.4 to 685) (n = 53) (p = 0.009). Significant correlation was found between initial elastase values and subsequent requirement for mechanical ventilation (p = 0.01), lowest arterial oxygen saturation/oxygen supplementation recorded (p = 0.003), and organ failure score (p = 0.006). This study shows that within minutes of the initiating trauma event, there is evidence of enhanced neutrophil degranulation as manifested by elevated levels of immunoreactive neutrophil elastase in the peripheral blood. The level of this enzyme correlates with the degree of subsequent lung injury and ARDS. These findings reinforce the importance of neutrophils and their secretory products in early ARDS disease pathogenesis.

Adolescent

Role of selectins in development of adult respiratory distress syndrome.

The acute lung injury of adult respiratory distress syndrome (ARDS) is characterised by inflammatory cell accumulation and activation in the lung. Selectins are a family of adhesion molecules implicated in leucocyte-endothelial adhesion, whose receptors can exist in a cleaved, soluble form. We investigated whether circulating soluble selectin adhesion molecules, obtained from ARDS at-risk patients, were associated with subsequent ARDS development. 82 patients, at risk of ARDS, were enrolled from three well-defined groups (multiple trauma, pancreatitis, perforated bowel). Plasma samples were obtained on hospital presentation and soluble L, E, and P, selectins were quantified with a sandwich enzyme-linked immunosorbent assay (ELISA). 14 patients subsequently developed ARDS. Initial plasma soluble L-selectin (sL-selectin) levels were significantly lower in patients who progressed to ARDS compared to those who did not (p = 0.0001; 95% Cl for mean in ARDS patients as percent of that in non-ARDS patients, 27-61%). Moreover concentrations were lower than in 62 normal volunteers (range 0.37-6.55, median 1.83 micrograms/mL, n = 62), suggesting that a selective reduction of sL-selectin correlates with susceptibility. In addition, a significant correlation was found between low values of sL-selectin and indices of subsequent lung injury including requirement for ventilation (p = 0.0001) and degree of respiratory failure (p = 0.0001). A significant correlation was also found between low values of sL-selectin and patient mortality (p = 0.002). These results elucidate the inflammatory cell endothelial interactions in the early stages of ARDS and may be of prognostic value.

Acute Disease

Plasma endothelin following cardiac arrest: differences between survivors and non-survivors.

Cardiac arrest is associated with major metabolic disturbances, including severe hypoxia and large increases in circulating catecholamines, both of which are known to stimulate generation of the potent endothelium-derived vasoconstrictor peptide endothelin-1. We have, therefore, examined plasma immunoreactive endothelin concentrations following cardiac arrest. Blood was sampled at 10-min intervals from a central venous catheter inserted at onset of resuscitation in 38 patients (13 female; mean age, 67 years) presenting with cardiac arrest to the Accident and Emergency Department at the Royal Infirmary of Edinburgh. Plasma immunoreactive endothelin concentrations (mean +/- S.D.) in patients following cardiac arrest (5.4 +/- 2.3 pg/ml) were no different from those in healthy subjects (5.1 +/- 1.2 pg/ml). There was no significant difference between endothelin concentrations at presentation in survivors and non-survivors of cardiac arrest. However, non-survivors had a significant fall in endothelin concentrations with time from onset of resuscitation from 5.4 +/- 2.2 pg/ml to 3.5 +/- 1.8 pg/ml (P = 0.002), while survivors had a non-significant increase in concentrations. On multiple regression analysis there was a significant association between higher plasma endothelin concentration and survival (r = 0.37; P = 0.009). The failure of plasma endothelin to increase after cardiac arrest is unexpected. Although the fall in plasma endothelin with time in non-survivors may reflect the adverse physiological milieu that occurs during cardiac arrest, it is also possible that low endothelin concentrations contribute to the poor prognosis in this condition.

Aged

Assessment of the active compression-decompression device (ACD) in cardiopulmonary resuscitation using transoesophageal echocardiography.

Transoesophageal echocardiography was used to investigate the haemodynamic profile achieved during active compression-decompression cardiopulmonary resuscitation in humans. The mechanism of antegrade blood flow achieved by ACD-CPR is consistent with the cardiac pump theory. Improved right heart compression, antegrade blood flow patterns and left ventricular filling were observed in some patients during ACD-CPR.

Aged

Out of hospital needlestick injuries.

Retrospective analysis showed that 67 children had presented in Edinburgh with needlestick injuries on 70 occasions over five years. Worryingly, 10 children sustained injuries pretending to be intravenous drug abusers. Despite risks of hepatitis B and HIV infection, protection and follow up were inadequate. Publicity about discarded needles and a treatment plan for use in accident and emergency departments are recommended.

Acquired Immunodeficiency Syndrome