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Biomedical subjects

G D Perkins

Publications and source records attributed to G D Perkins.

16 recordsLinked to original sources

In vitro and in vivo effects of salbutamol on neutrophil function in acute lung injury.

BACKGROUND: Intravenous salbutamol (albuterol) reduces lung water in patients with the acute respiratory distress syndrome (ARDS). Experimental data show that it also reduces pulmonary neutrophil accumulation or activation and inflammation in ARDS. AIM: To investigate the effects of salbutamol on neutrophil function. METHODS: The in vitro effects of salbutamol on neutrophil function were determined. Blood and bronchoalveolar lavage (BAL) fluid were collected from 35 patients with acute lung injury (ALI)/ARDS, 14 patients at risk from ARDS and 7 ventilated controls at baseline and after 4 days' treatment with placebo or salbutamol (ALI/ARDS group). Alveolar-capillary permeability was measured in vivo by thermodilution (PiCCO). Neutrophil activation, adhesion molecule expression and inflammatory cytokines were measured. RESULTS: In vitro, physiological concentrations of salbutamol had no effect on neutrophil chemotaxis, viability or apoptosis. Patients with ALI/ARDS showed increased neutrophil activation and adhesion molecule expression compared with at risk-patients and ventilated controls. There were associations between alveolar-capillary permeability and BAL myeloperoxidase (r = 0.4, p = 0.038) and BAL interleukin 8 (r = 0.38, p = 0.033). In patients with ALI/ARDS, salbutamol increased numbers of circulating neutrophils but had no effect on alveolar neutrophils. CONCLUSION: At the onset of ALI/ARDS, there is increased neutrophil recruitment and activation. Physiological concentrations of salbutamol did not alter neutrophil chemotaxis, viability or apoptosis in vitro. In vivo, salbutamol increased circulating neutrophils, but had no effect on alveolar neutrophils or on neutrophil activation. These data suggest that the beneficial effects of salbutamol in reducing lung water are unrelated to modulation of neutrophil-dependent inflammatory pathways.

Albuterol↗

Critically injured patients, inaccessible airways, and laryngeal mask airways.

Managing the airway of a critically injured trauma patient in the prehospital environment is challenging, especially when access to the patient's airway is limited as is often the case in vehicle entrapment incidents. This paper reports the use of the laryngeal mask airway as an adjunct to airway management when attempts using simple airway management techniques have failed to provide adequate oxygenation and ventilation and limited access to the patient precluded endotracheal intubation.

Accidents, Traffic↗

Regulation of vascular endothelial growth factor bioactivity in patients with acute lung injury.

BACKGROUND: Reduced bioactive vascular endothelial growth factor (VEGF) has been demonstrated in several inflammatory lung conditions including the acute respiratory distress syndrome (ARDS). sVEGFR-1, a soluble form of VEGF-1 receptor, is a potent natural inhibitor of VEGF. We hypothesised that sVEGFR-1 plays an important role in the regulation of the bioactivity of VEGF within the lung in patients with ARDS. METHODS: Forty one patients with ARDS, 12 at risk of developing ARDS, and 16 normal controls were studied. Bioactive VEGF, total VEGF, and sVEGFR-1 were measured by ELISA in plasma and bronchoalveolar lavage (BAL) fluid. Reverse transcriptase polymerase chain reaction for sVEGFR-1 was performed on BAL cells. RESULTS: sVEGFR-1 was detectable in the BAL fluid of 48% (20/41) of patients with early ARDS (1.4-54.8 ng/ml epithelial lining fluid (ELF)) compared with 8% (1/12) at risk patients (p = 0.017) and none of the normal controls (p = 0.002). By day 4 sVEGFR-1 was detectable in only 2/18 ARDS patients (p = 0.008). Patients with detectable sVEGFR-1 had lower ELF median (IQR) levels of bioactive VEGF than those without detectable sVEGFR-1 (1415.2 (474.9-3192) pg/ml v 4761 (1349-7596.6) pg/ml, median difference 3346 pg/ml (95% CI 305.1 to 14711.9), p = 0.016), but there was no difference in total VEGF levels. BAL cells expressed mRNA for sVEGFR-1 and produced sVEGFR-1 protein which increased following incubation with tumour necrosis factor alpha. CONCLUSION: This study shows for the first time the presence of sVEGFR-1 in the BAL fluid of patients with ARDS. This may explain the presence of reduced bioactive VEGF in patients early in the course of ARDS.

Adolescent↗

Over-the-head CPR.

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Cardiopulmonary Resuscitation↗

What is the optimal duration of ventilation in the prone position in acute lung injury and acute respiratory distress syndrome?

OBJECTIVE: To evaluate the effects of prone ventilation on respiratory parameters and extravascular lung water (EVLW) in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) in order to characterise the optimal duration of ventilation in the prone position. DESIGN: Prospective, observational study. SETTING: Nine-bed general intensive care unit. PATIENTS: Eleven patients with refractory hypoxaemia due to ALI/ARDS were prospectively investigated during 12 consecutive episodes of prone ventilation. INTERVENTIONS: Ventilation in the prone position for 18 h. MEASUREMENTS AND MAIN RESULTS: Measurements were obtained supine and after 1, 2, 6, 12 and 18 h in the prone position and 1 h after returning supine. There was a progressive improvement in PaO(2)/fraction of inspired oxygen (FIO(2)) ratio which reached significance after 12 h [121 (81-151) to 258 (187-329) torr; p<0.05]. EVLW index increased transiently at 1 h [14.2 (7.6-20.8) to 15.1 (9.0-20.2); p=0.05] and thereafter declined progressively and was significantly decreased at 18 h [12.1 (7.2-17.0); p=0.043]. The shunt fraction showed an early fall [0.41 (0.40-0.42) to 0.31 (0.30-0.32) at 1 h; p<0.001] preceding a subsequent progressive fall [0.22 (0.21-0.23) at 18 h; p<0.001]. CONCLUSIONS: Over the 18 h period studied there was progressive improvement in gas exchange, pulmonary shunt and EVLW. Although it is not possible to exclude that improvement over this period was unrelated to prone positioning, these findings suggests that ventilation in the prone position for more prolonged periods may be required for optimal improvement and warrants further study.

Adolescent↗

Delays in defibrillation: influence of different monitoring techniques.

BACKGROUND: Rapid defibrillation is the most important intervention required for a patient in cardiac arrest due to ventricular fibrillation or ventricular tachycardia. Isolated case reports of spurious asystole may have seen a change in practice, moving away from monitoring through defibrillator paddles and gel pads in favour of attaching electrocardiograph (ECG) leads for the initial monitoring of a collapsed patient. We surveyed current preferences for initial monitoring and estimated the difference in time taken to deliver the first shock with the following three monitoring techniques: defibrillator paddles and gel pads, ECG leads and hands-free adhesive pads. METHODS: Sixty Advanced Life Support (ALS) course directors, selected at random, were questioned to establish their current practice. Twenty ALS providers received 5 min revision in the three techniques for the initial monitoring of a collapsed patient and were then randomly tested to measure the time from confirmation of arrest to the first shock. RESULTS: Forty-two directors indicated their preferred methods for initial monitoring as 74% leads, 21% paddles and 5% hands-free adhesive pads. Before testing, 10 providers preferred paddles and 10 preferred leads. Monitoring through leads 54 (range 49-65) s was significantly slower than paddles 28 (24-31) s, P < 0.01 and adhesive pads 23 (19-27) s, P < 0.01. There was no significant difference in the time taken between paddles and adhesive pads. CONCLUSION: The current practice of monitoring through leads delays the time to deliver the first shock. We recommend that initial monitoring through leads be discontinued in favour of hands-free adhesive pads or defibrillator paddles/gel pads.

Electric Countershock↗

The effect of differing support surfaces on the efficacy of chest compressions using a resuscitation manikin model.

AIM: External chest compression (ECC) efficacy is influenced by factors including the surface supporting the patient. Air-filled support surfaces are deflated for cardiopulmonary resuscitation, with little evidence to substantiate this. We investigated the effect that differing support surfaces had on ECC efficacy using a CPR manikin model. METHODOLOGY: Four participants carried out four cycles of ECC with an assistant ventilating. The subjects were blinded to the seven support surfaces and the order was randomised. For each participant/surface combination, ECC variables and the participants' perceptions were measured. RESULTS: Participants produced effective ECC with the manikin on the floor (mean proportion correct, 94.5%; mean depth, 42.5 mm). Compared with the floor: the proportion of correct ECC was less for the overlay inflated (P<0.05); the depth of ECC was less effective (30-37 mm) for the overlay inflated/deflated and low-air-loss inflated and foam mattresses (P<0.05). The foam mattress, overlay inflated/deflated, and low-air-loss inflated were perceived as being less stable and as having reduced ECC efficacy compared with the floor. There was no difference or agreement, regarding subjects' perceptions or ECC variables, between the support surfaces or between inflated/deflated air-filled support surfaces. CONCLUSION: The efficacy of ECC is affected by the support surfaces. There seems little evidence to substantiate deflating all air-filled support surfaces for CPR.

Beds↗

Variability in the assessment of advanced life support skills.

The number of short 'life support' and emergency care courses available are increasing. Variability in examiner assessments has been reported previously in more traditional types of examinations but there is little data on the reliability of the assessments used on these newer courses. This study evaluated the reliability and consistency of instructor marking for the Resuscitation Council UK Advanced Life Support Course. Twenty five instructors from 15 centres throughout the UK were shown four staged video recorded defibrillation tests (one repeated) and three cardiac arrest simulation tests in order to assess inter-observer and intra-observer variability. These tests form part of the final assessment of competence on an Advanced Life Support course. Significant levels of variability were demonstrated between instructors with poor levels of agreement of 52-80% for defibrillation tests and 52-100% for cardiac arrest simulation tests. There was evidence of differences in the observation/recognition of errors and rating tendencies of instructors. Four instructors made a different pass/fail decision when shown defibrillation test 2 for a second time leading to only moderate levels of intra-observer agreement (kappa=0.43). In conclusion there is significant variability between instructors in the assessment of advanced life support skills, which may undermine the present assessment mechanisms for the advanced life support course. Validation of the assessment tools for the rapidly growing number of life support courses is required with urgent steps to improve reliability where required.

Advanced Cardiac Life Support↗

Pyoderma gangrenosum.

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Antibodies, Antineutrophil Cytoplasmic↗

Basic life support training for health care students.

This paper describes a novel method for delivering basic life support training to undergraduate healthcare students. A comprehensive 8 h programme is organised and delivered by undergraduate students to their peers. These students have undergone training as basic life support instructors validated by the Royal Life Saving Society UK. The course is delivered to multiprofessional groups of medical, dental, physiotherapy, biomaterial and nursing undergraduates. It has been well received by students and academic staff and provides a solution to reduce the workload of over burdened clinical staff while at the same time enhancing quality. It forms part of an overall strategy for improving resuscitation training for undergraduates from all disciplines.

Cardiopulmonary Resuscitation↗

Perioperative care of a Jehovah's Witness with a leaking abdominal aortic aneurysm.

We describe a Jehovah's Witness patient who survived emergency repair of a leaking abdominal aortic aneurysm. In accordance with his beliefs, the patient expressed a wish not to be given blood and this was respected. At completion of surgery, his haemoglobin was 2.8 g dl-1 and his albumin was 8 g l-1. He was kept heavily sedated in the intensive care unit and treated with i.v. iron, folinic acid and s.c. epoetin alfa. He was discharged to the high dependency unit 18 days after surgery with a haemoglobin of 6.4 g dl-1 and an albumin of 27 g l-1. After rehabilitation, he was discharged home approximately 14 weeks after surgery.

Aged↗