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Biomedical subjects

Gavin D Perkins

Publications and source records attributed to Gavin D Perkins.

At least 19 recordsLinked to original sources

The impact of manual defibrillation technique on no-flow time during simulated cardiopulmonary resuscitation.

INTRODUCTION: Rapid defibrillation is the most effective strategy for establishing return of spontaneous circulation following cardiac arrest due to ventricular fibrillation. The aim of this study is to measure the delay due to of charging the defibrillator during chest compression in an attempt to reduce the duration of the pre-shock pause in between cessation of chest compressions and shock delivery as advocated by the American Heart Association (AHA) guidelines compared to charging the defibrillator immediately following rhythm analysis without resuming chest compressions as recommended by the European Resuscitation Council (ERC). METHODS: This was a randomised controlled cross over trial comparing pre-shock pause times when defibrillation was performed on a manikin according to the AHA and ERC guidelines using paddles and hands free defibrillation systems. RESULTS: The pre-shock pause between cessation of chest compression and shock delivery was significantly different between techniques (Friedman test, P<0.0001). ERC paddles technique had the greatest pre-shock pause (7.4 s [6.7-11.2]) followed by ERC hands free (7.0 s [6.5-8.5]) and AHA paddles (1.6 s [1.1-2.3]). AHA hands free took the least amount of time (1.5 s [0.8-1.5]). Extrapolating these data to older defibrillators with longer charge times saw pre-shock pause intervals of 9 s (Codemaster XL) and 12 s (Lifepak 20) with the ERC approach. CONCLUSION: This study demonstrated clinically significant delays to defibrillation by analysing and charging the defibrillator without performing concurrent chest compressions. In a simulated scenario, charging the defibrillator whilst performing chest compressions was perceived as safe and significantly reduced the pre-shock pause between cessation of chest compression and shock delivery.

Adult↗

Teaching recognition of agonal breathing improves accuracy of diagnosing cardiac arrest.

OBJECTIVE: Agonal breathing is present in up to 40% of pre-hospital cardiac arrests and is commonly mistaken as a sign of circulation leading to omission of bystander resuscitation. The aim of this study was to test the hypothesis that specific tuition on agonal breathing improves the accuracy of checking for signs of circulation as a diagnostic test for cardiac arrest. METHODS: First year medical students were randomised to control or intervention groups. The control group were taught standard CPR according to current guidelines. The intervention group received standard CPR training plus specific tuition on the characteristics of agonal breathing. Two weeks after initial training, the students' ability to recognise cardiac arrest was tested using a simulated cardiac arrest victim demonstrating normal, absent or agonal breathing. Diagnostic accuracy, sensitivity and specificity for the decision to start CPR was calculated. RESULTS: Sixty-four students were equally randomised to intervention and control groups. The intervention group had greater diagnostic accuracy for cardiac arrest compared to the control group (90% versus 78%, P=0.03). The intervention group were more likely to recognise cardiac arrest correctly and initiate CPR than the control group (sensitivity 90% versus 78%, P=0.02). The improved results were predominantly due to recognition that agonal breathing is a sign of cardiac arrest (75% intervention group versus 43% control group, P=0.01). CONCLUSION: This study demonstrates improved diagnostic accuracy and sensitivity of "checking for signs of circulation" by teaching CPR providers to recognise agonal breathing as a sign of cardiac arrest.

Cardiopulmonary Resuscitation↗

Effects of a backboard, bed height, and operator position on compression depth during simulated resuscitation.

OBJECTIVE: To investigate the effect of a backboard, cardiopulmonary resuscitation (CPR) provider body position and bed height on the quality of chest compression during simulated in-hospital resuscitation. DESIGN AND SETTING: Randomised controlled cross-over trial in a university hospital. PARTICIPANTS: Second-year medical student basic life support instructors. INTERVENTIONS: Chest compressions performed on a resuscitation manikin placed on a hospital bed with/without a CPR backboard, kneeling on the bed adjacent to the manikin and lowering the height of the bed. MEASUREMENTS AND RESULTS: Sub-optimal chest compressions were performed on all surfaces. There were no differences in compression depth: standard CPR, 29+/-7 mm; backboard CPR, 31+/-10 mm; kneeling on the bed, 30+/-7 mm; lowering bed height, 32+/-10 mm. Compression rate and duty cycle were similar on each surface. Participants failed to recognise their poor quality CPR, and there was no difference in assessment of fatigue or efficacy of CPR between surfaces. CONCLUSIONS: In contrast to current guidelines, the use of a CPR backboard did not improve chest compressions. Furthermore, kneeling on the bed adjacent to the victim or lowering bed height did not impact materially on the quality of chest compression. These findings should be validated in clinical studies.

Analysis of Variance↗

Role of nonbronchoscopic lavage for investigating alveolar inflammation and permeability in acute respiratory distress syndrome.

OBJECTIVE: Nonbronchoscopic bronchoalveolar lavage is often used as an alternative to bronchoscopic bronchoalveolar lavage in the diagnosis of ventilator-associated pneumonia. We have previously reported an improved safety profile for nonbronchoscopic lavage in patients with lung injury, suggesting that this may be a better technique in this patient group. The objective of this study was to determine whether nonbronchoscopic lavage could be used as an alternative to bronchoscopic lavage for the assessment of alveolar permeability and inflammation in patients at risk for acute respiratory distress syndrome (ARDS) or with ARDS. DESIGN: Prospective randomized crossover trial. PATIENTS: Intubated patients with ARDS or at risk of ARDS. INTERVENTIONS: Bronchoscopic and nonbronchoscopic lavage in the same patient, 15 mins apart. MEASUREMENTS AND MAIN RESULTS: Twenty-one patients with ARDS and 20 patients at risk of ARDS were recruited and underwent nonbronchoscopic and bronchoscopic lavage in randomized order. Despite similar volumes of lavage fluid, nonbronchoscopic lavage had fewer cells and an increased ratio of bronchial epithelial cells to macrophages. Although average concentrations of myeloperoxidase and total protein, the protein permeability index, and the epithelial-lining fluid volume were similar with the two techniques and demonstrated moderate linear associations, Bland and Altman analysis revealed poor comparability, with substantial side-to-side variability and wide 95% limits of agreement. Furthermore, unlike bronchoscopic lavage, nonbronchoscopic lavage was unable to differentiate between patients with ARDS and those at risk of ARDS. CONCLUSIONS: Nonbronchoscopic lavage is not comparable to bronchoscopic lavage and as such cannot be used as an alternative to bronchoscopic lavage for assessing alveolar inflammation in patients with ARDS.

Adult↗

Over-the-head CPR.

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Cardiopulmonary Resuscitation↗

Recall after cardiac arrest scenario testing.

The Resuscitation Council (UK) Advanced Life Support (ALS) Course is a multidisciplinary training course which teaches participants how to manage the resuscitation of a patient at risk of or in cardiac arrest. To reduce variability in assessments, four standardised patient scenarios have been developed with common performance criteria. The aim of the study was to establish how much candidates remembered about their test in order to assess the potential for collusion. Eighty-nine candidates were asked immediately after testing what they remembered about their ALS scenario. Recall of the underlying problem with the simulated patient was good (85 [96%]). Forty-two [47%] correctly remembered the initial cardiac arrest rhythm and 55 [61%] the subsequent cardiac arrest rhythm. Fifty-nine [60%] candidates passed the assessment. Candidates who passed the assessment were significantly more likely to correctly recall the initial and subsequent cardiac arrest rhythms than those who did not. However, even in this group, the overall recall of all elements of the scenario was correct in only 49% of instances. This study demonstrated that immediately after testing candidates had good recall of the initial clinical scenario with which they were presented, but poor recall of cardiac arrest rhythms during the simulated resuscitation attempt. These findings provide some reassurance that the likelihood of successful collusion improving subsequent candidates performance is likely to be small as recall of the scenario progression is limited.

Advanced Cardiac Life Support↗

The beta-agonist lung injury trial (BALTI): a randomized placebo-controlled clinical trial.

RATIONALE: Experimental data suggest that manipulation of alveolar fluid clearance with beta-agonists can accelerate the resolution of alveolar edema and improve survival. OBJECTIVE: To determine if a sustained infusion of intravenous salbutamol (albuterol) would accelerate the resolution of alveolar edema in adult patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). METHODS: This was a single-center, double-blind, randomized controlled trial. Patients with ALI/ARDS were randomized to treatment with intravenous salbutamol (15 microg kg(-1) h(-1)) or placebo for 7 d. The primary endpoint was extravascular lung water measured by thermodilution (PiCCO) at Day 7. MEASUREMENTS AND MAIN RESULTS: Sixty-six patients were screened; of these, 40 met the inclusion criteria and were enrolled during 2001-2003. Patients in the salbutamol group had significantly lower lung water at Day 7 than the placebo group (9.2 +/- 6 vs. 13.2 +/- 3 ml kg(-1); 95% confidence interval difference, 0.2-8.3 ml kg(-1); p = 0.038). Plateau airway pressure was lower at Day 7 in the salbutamol group (23.9 +/- 3.8 cm H2O) versus placebo (29.5 +/- 7.2 cm H2O; p = 0.049). There was a trend toward lower Murray lung injury score at Day 7 in the salbutamol group (1.7 +/- 0.9) versus placebo (2.0 +/- 0.6; p = 0.2). Patients in the salbutamol group had a higher incidence of supraventricular arrhythmias (26 vs. 10%; p = 0.2). CONCLUSION: Although further research is required to confirm the efficacy and safety of intravenous salbutamol in ALI/ARDS, this trial provides the first proof of principle that, in humans with ALI/ARDS, sustained treatment with intravenous beta-agonists reduces extravascular lung water.

Adrenergic beta-Agonists↗

The Acute Care Undergraduate TEaching (ACUTE) Initiative: consensus development of core competencies in acute care for undergraduates in the United Kingdom.

BACKGROUND: The care of the acutely ill patient in hospital is often sub-optimal. Poor recognition of critical illness combined with a lack of knowledge, failure to appreciate the clinical urgency of a situation, a lack of supervision, failure to seek advice and poor communication have been identified as contributory factors. At present the training of medical students in these important skills is fragmented. The aim of this study was to use consensus techniques to identify the core competencies in the care of acutely ill or arrested adult patients that medical students should possess at the point of graduation. DESIGN: Healthcare professionals were invited to contribute suggestions for competencies to a website as part of a modified Delphi survey. The competency proposals were grouped into themes and rated by a nominal group comprised of physicians, nurses and students from the UK. The nominal group rated the importance of each competency using a 5-point Likert scale. RESULTS: A total of 359 healthcare professionals contributed 2,629 competency suggestions during the Delphi survey. These were reduced to 88 representative themes covering: airway and oxygenation; breathing and ventilation; circulation; confusion and coma; drugs, therapeutics and protocols; clinical examination; monitoring and investigations; team-working, organisation and communication; patient and societal needs; trauma; equipment; pre-hospital care; infection and inflammation. The nominal group identified 71 essential and 16 optional competencies which students should possess at the point of graduation. CONCLUSIONS: We propose these competencies form a core set for undergraduate training in resuscitation and acute care.

Acute Disease↗

In-water resuscitation: a pilot evaluation.

INTRODUCTION: The first and most important treatment for the apnoeic drowning victim is the rapid alleviation of hypoxia by artificial ventilation. Recent studies have suggested that commencing resuscitative efforts with the victim still in the water may be beneficial. The aim of this pilot study was to evaluate the feasibility and efficacy of in-water unsupported rescue breathing. METHODS: Three lifeguards were taught how to perform in-water unsupported rescue breathing. Ventilation volume, inflation duration were recorded from a modified Laerdal resuscitation manikin. The rescue duration was recorded and compared to a rescue undertaken without in-water resuscitation. RESULTS: The three lifeguards performed between seven and nine ventilations during each simulated rescue. This gave average inflation volumes for each lifeguard of 711 ml (S.D. 166), 750 ml (S.D. 108), 629 ml (S.D. 182) and average inflation duration of 0.8s (S.D. 0.3), 0.9s (S.D. 0.2) and 0.6s (S.D. 0.1). The rescue duration was increased from an average time of 1 min 10 s to 1 min 24 s by performing in-water resuscitation. CONCLUSION: This study has demonstrated the feasibility and potential efficacy of in-water unsupported rescue breathing with a victim in deep water. Furthermore, the technique was not associated with an undue prolongation of the rescue duration over a 50 m rescue. In circumstances where the trained lifeguard finds themselves with an apnoeic victim in the water, with no buoyant rescue aid available, they may consider the application of in-water, unsupported rescue breathing, especially if recovery to dry land is likely to be delayed. The effectiveness of this technique, however, remains to be proven in the open water environment.

Apnea↗

CPREzy: an evaluation during simulated cardiac arrest on a hospital bed.

CPREzy is a new adjunct designed to improve the application of manual external chest compressions (ECC) during cardiopulmonary resuscitation (CPR). The aim of this study was to determine the effect of using the CPREzy device compared to standard CPR during the simulated resuscitation of a patient on a hospital bed. Twenty medical student volunteers were randomised using a cross over trial design to perform 3 min of continuous ECC using CPREzy and standard CPR. There was a significant improvement in ECC depth with CPREzy compared to standard CPR 42.9 (4.4) mm versus 34.2 (7.6): mm, P = 0.001; 95% CI d.f. 4.4-12.9 mm. This translated to a reduction in the percentage of shallow compressions (<38 mm) with CPREzy 16 (23)% compared to standard CPR 59 (44)%, P = 0.003. There was a small increase in the percentage of compression regarded excessive (>51 mm): CPREzy 6.5 (19)% versus standard CPR 0 (0.1)%. P = 0.012). There was no difference in compression rate or duty cycle between techniques. Equal numbers of participants (40% in each group) performed one of more incorrectly placed chest compression. However the total number of incorrect compressions was higher for the CPREzy group (26% versus 3.9% standard CPR, P < 0.001). This was due to a higher number of low compressions (26% of total compressions for CPREzy versus 1% for standard CPR, P < 0.001). In conclusion, CPREzy was associated with significant improvements in ECC performance. Further animal and clinical studies are required to validate this finding in vivo and to see if it translates to an improvement in outcome in human victims of cardiac arrest.

Adult↗

Birmingham assessment of breathing study (BABS).

BACKGROUND: Current international resuscitation guidelines for lay people rely on the assessment of "normal breathing" as a key sign of breathing and circulation. However, it is not known how accurately laypersons can discriminate between "normal" and "abnormal" breathing. The aim of this study was to test the ability of medical students to discriminate between simulated normal and abnormal breathing patterns and select the correct treatment. METHODS: Six video clips of simulated breathing were recorded showing: normal; abnormal -shallow, rapid, agonal (obstructed and unobstructed airways); or absent breathing. The clips were validated by three experienced emergency practitioners and then shown in a random order to 48 second-year medical students. For each clip observers were asked to indicate: "Is this patient breathing?" (yes-normal, yes-abnormal, no) and "What action would you take?" (rescue breathing or recovery position). RESULTS: All experts correctly identified the breathing type and agreed on an appropriate emergency action. Students identified normal breathing as: normal 61%, abnormal 33% and absent 6%; abnormal breathing as: normal 29%, abnormal 61%, absent 10%; and absent breathing as: normal 8%, abnormal 6%, absent 85%. Correct actions were selected in 86% during normal breathing, 51% during abnormal breathing and 86% during absent breathing. The sensitivity for observers correctly identifying normal from abnormal breathing was 60% and specificity 75% and for selecting the correct action was 42% and 80%, respectively. CONCLUSIONS: Medical students were unable to identify normal breathing from abnormal breathing reliably resulting in a high number of inappropriate, potentially harmful actions. Further evaluation of the optimal method for assessing for signs of breathing and circulation is required.

Clinical Competence↗

Safety and tolerability of nonbronchoscopic lavage in ARDS.

STUDY OBJECTIVE: This study compared the safety profiles of bronchoscopic lavage with nonbronchoscopic lavage in the investigation of patients with acute lung injury (ALI) or ARDS. DESIGN: Single-center, randomized, cross-over study. SETTING: General ICU in the United Kingdom. PARTICIPANTS: Fourteen patients with ALI or ARDS. INTERVENTIONS: Bronchoscopic BAL and nonbronchoscopic BAL 1 h apart. MEASUREMENTS AND RESULTS: Hemodynamic and ventilatory parameters were recorded during and for 1 h following each procedure. On average, bronchoscopic lavage took longer to perform than nonbronchoscopic lavage (7 min and 6 s vs 2 min and 28 s, p < 0.001). During the procedures, bronchoscopic lavage increased heart rate and systolic BP more than nonbronchoscopic lavage (23% vs 10% [p < 0.01] and 18% vs 7% [p < 0.01]). Three patients had ST-segment depression during bronchoscopic, and one patient had ST-segment depression during nonbronchoscopic lavage (p = 0.298). Bronchoscopic lavage reduced minute ventilation by 63 +/- 17.3%, while nonbronchoscopic lavage only reduced it by 36 +/- 21.9% (p < 0.001). Paco(2) rose more after bronchoscopic lavage than after nonbronchoscopic lavage. CONCLUSION: Nonbronchoscopic lavage is associated with less marked physiologic derangements than bronchoscopic lavage. Further studies are required to validate the hypothesis that nonbronchoscopic lavage may be safer in patients with unstable coronary heart disease or head injury/raised intracranial pressure who are at risk from unpredictable fluctuations in hemodynamic and ventilatory profiles.

Aged↗

A comparison between over-the-head and standard cardiopulmonary resuscitation.

BACKGROUND: Standard cardiopulmonary resuscitation (CPR) is performed by kneeling adjacent to the side of the casualty. In certain circumstances it may be difficult or impossible to perform CPR in this position, for example in confined spaces such as a narrow corridor, aircraft or train gangway. The aim of this study was to investigate the technique of over-the-head CPR (OTH CPR), where the CPR provider kneels above the casualty and performs chest compressions OTH of the casualty. METHODS: Twenty volunteers were randomised to a cross over trial where they performed standard and OTH CPR at a 7-day interval. Compression and ventilation variables were recorded on the Laerdal Resusci Annie VAM system. RESULTS: Chest compression depth and ventilation volume declined over time (0-3 min P < 0.001). There was no difference in compression rate, depth, duty cycle or ventilation rate, inflation rate and ventilation volume between techniques. Hand position was incorrect more frequently in the standard compared to the OTH group (incorrect compressions 300 versus 76, respectively, P < 0.001) due principally to a greater proportion of low positioned compressions in the standard CPR group. CONCLUSION: OTH CPR appears equally effective as standard CPR with some marginal advantages in correct hand placement. We suggest that in situations where it is not possible to perform standard CPR, OTH CPR may be considered as a suitable alternative.

Analysis of Variance↗