The interaction and pharmacological modulation of the cardiorespiratory responses to primary thoracic blast injury, haemorrhage resuscitation

Blast injuries represent a problem for civilian and military populations. The response to thoracic blast injury involves a reflex bradycardia, hypotension and apnoea. Casualties who have suffered a blast injury are likely to receive morphine as an early treatment, and may go on to suffer a haemorrhage, thus requiring fluid resuscitation. Aims of this thesis included determination of the effect of blast injury on the response to haemorrhage and whether these responses or their interaction are modified by morphine, and to compare the cardiovascular effects of early and late resuscitation with different solutions following blast injury and haemorrhage. Early cessation of the blast-induced apnoea is important if the patient is to adequately maintain arterial oxygen tensions and thus prevent the development of tissue hypoxia and a subsequent secondary inflammatory response. Therefore, the final aim of this thesis was to determine whether doxapram could shorten the duration of apnoea induced by thoracic blast. Results confirmed that the response to thoracic blast injury involves a bradycardia, hypotension and apnoea, and also a vasodilation and a reduction in blood flow in the femoral vascular bed. New findings from this thesis show that thoracic blast augments the bradycardia and hypotension seen during haemorrhage and that morphine attenuates this effect. The hypovolaemic blast-injured patient may be resuscitated early or late after haemorrhage with blood, 0.9% saline, colloids (modified gelatin and hydroxyethyl starch) hypertonic saline or hypertonic/hydroxyethyl starch. These fluids restored blood pressure and femoral blood flow to pre-haemorrhage levels for at least 30 minutes. However, resuscitation with hypertonic saline/de>ttran was shown to be deleterious following blast injury and haemorrhage as blood pressure and femoral blood flow was not maintained for longer than 5 minutes following resuscitation with this fluid. The blast-induced apnoea and hypotension can be significantly attenuated by doxapram immediately following blast injury. This respiratory stimulant may also result in an improvement in venfilation/perfusion matching in the lungs and thus better fissue oxygenation, as administration of doxapram resulted in an improvement in the indices of metabolic acidosis. The new information gained from the work covered by this thesis could potentially lead to better treatment of the blast-injured victim

Characteristics of Special Circulations

Blood flow through a vascular bed is usually determined by the pressure gradient across it and the diameter of the precapillary resistance vessels. Special circulations have additional specific features of blood flow control. Several organs control their blood supply by autoregulation. Coronary blood flow is linked to myocardial oxygen consumption,primarily by a metabolic mechanism. Increases in demand or decreases in supply of oxygen cause the release of vasodilator metabolites, which act on vascular smooth muscle to cause vessel relaxation and hence increase blood flow. Cerebral blood flow is primarily regulated by a myogenic mechanism whereby increases in transmural pressure stretch the vascular smooth muscle, which responds by contracting. Renal blood flow is regulated by both extrinsic and intrinsic mechanisms; sympathetic vasoconstriction of the afferent arterioles reduces renal blood flow in response to a decrease in effective circulating volume, myogenic mechanisms and tubuloglomerular feedback,as well as the release of vasoactive metabolites from the vascular endothelium regulate renal blood flow intrinsically. Hepatic blood flow is delivered via the portal vein and hepatic artery, and the amount of flow varies in these vessels reciprocally to maintain constant total blood flow. The pulmonary circulation receives the entire cardiac output, and blood flow is regulated both passively and actively. Pulmonary vessels are highly distensible and can accommodate increases in blood flow without significant increases in pressure

'10% of your medical students will cause 90% of your problems': a prospective correlational study

• Objectives Our aim was to explore the relationship between medical student Conscientiousness Index scores and indicators of later clinical performance held in the UK Medical Education Database. Objectives were to determine whether conscientiousness in first and second year medical students predicts later performance in medical school and in early practice. Policy implications would permit targeted remediation where necessary or aid in selection. • Design Prospective correlational study • Setting A single UK medical school and early years of practice, 2005-2018. • Participants Data were obtained from the UK Medical Education Database (UKMED) on 858 students. Full outcome data was available for variable numbers of participants, as described in the text. • Main outcome measures Scores on the UK Foundation Programme Office’s Situational Judgement Test (SJT) and Educational Performance Measure (EPM), the Prescribing Safety Assessment (PSA), and Annual Review of Competency Progression (ARCP) outcomes. • Results Linear regression analysis shows Conscientiousness Index scores significantly correlate with pre- and postgraduate performance variables,: SJT scores (R=0.373, R2=0.139, B=0.066, p<0.001, n=539); PSA scores (R=0.249, R2=0.062, B=0.343, p<0.001, n=462); EPM decile scores for the 1st (lowest) decile are significantly lower than the remaining 90% (P=0.003, n=539), as are PSA scores (p<0.001, n=463), and ARCP Year 2 scores (p=0.019, n=517). The Odds Ratio that students in the 1st decile fail to achieve the optimum ARCP outcome is 1.6126 (CI 1.1400 to 2.2809, p=0.0069, n=618). • Conclusions Conscientiousness Index scores in Year 1 and 2 of medical school have predictive value for later performance in knowledge, skills and clinical practice. This trait could be used either for selection, or for targeted remediation to avoid potential problems in the future

A study to investigate the effectiveness of SimMan® as an adjunct in teaching preclinical skills to medical students

Background: Following the GMC’s report on Tomorrow’s Doctors, greater emphasis has been placed on training in clinical skills, and the integration of clinical and basic sciences within the curriculum to promote the development of effective doctors. The use of simulation in the learning environment has the potential to support the development of clinical skills in preclinical medical students whilst in a ‘safe’ environment, but currently there is little evidence on its effectiveness. Methods: Seventy nine year one medical students were divided into two groups. A pre-test was conducted by both groups, after which one group performed chest examination on their peers whilst the other group examined the SimMan® manikin. Both groups subsequently performed a mid-test and crossed over so that the group that conducted peer examination examined the manikin and vice-versa. Finally a post-test was conducted. The students were scored for formative feedback whilst performing examinations. Students completed a feedback questionnaire at the end of the session. Data were analysed using a one-way ANOVA, independent t-test and 2- proportion Z test. Results: When the two groups were compared, there was no significant difference in their pre-test and post-test knowledge scores, whereas mid-test knowledge scores increased significantly (P < 0.001), with the group using SimMan® initially scoring higher. A significant increase in the test scores was seen in both groups after using SimMan® (P < 0.001). Students’ confidence increased significantly in differentiating between normal and abnormal signs (P < 0.001). Students highly valued the use of the manikin in the session with 96% of students reporting that it enhanced their learning experience. Conclusions: The study demonstrated a significant improvement in the students’ knowledge after examining the manikin and students also reported an increase in their confidence. Students’ feedback was generally very positive and they perceived the incorporation of manikin-based examinations useful to prepare them for future patient contact. The use of simulation in this context supports an integrated learning approach when used as an adjunct to peer examination, and can benefit the acquisition of clinical skills in preclinical medical students

Conscientious, competent and caring: producing the junior doctor of the future

This article is based on the Association for the Study of Medical Education Gold Medal Plenary for 2022, given by the first author. It outlines different ways in which medical training can be approached, based on his career and his work with colleagues. Among the attributes that it would be desirable to promote in future doctors are conscientiousness, competence and care for patients as individuals. This article explores each of these in separate sections. The first demonstrates that the trait of conscientiousness can be observed in first and second year medical students by their compliance in routine low level tasks such as attendance and submission of required work on time. A ‘conscientiousness index’ calculated on this basis is a statistically significant predictor of later events such as performance in exams, the prescribing safety assessment, and the UK situational judgement test in subsequent years, and also in postgraduate assessments such as Royal college exams and the annual reviews of competence progression. The second proposes that competence in tasks undertaken by junior doctors is better achieved by teaching on medical imaging, clinical skills and living anatomy than by cadaveric dissection. The final section argues that the incorporation of arts and humanities teaching into medical education is likely to lead to better understanding of the patient perspective in later practice

An Inexpensive Retrospective Standard Setting Method Based on Item Facilities

Background Standard setting is one of the most challenging aspects of assessment in high-stakes healthcare settings. The Angoff methodology is widely used, but poses a number of challenges, including conceptualisation of the just-passing candidate, and the time-cost of implementing the method. Cohen methodologies are inexpensive and rapid but rely on the performance of an individual candidate. A new method of standard setting, based on the entire cohort and every item, would be valuable. Methods We identified Borderline candidates by reviewing their performance across all assessments in an academic year. We plotted the item scores of the Borderline candidates in comparison with Facility for the whole cohort and fitted curves to the resulting distribution. Results It is observed that for any given Item, an equation of the form y ≈ C.eFx where y is the Facility of Borderline candidates on that Item, x is the observed Item Facility of the whole cohort, and C and F are constants, predicts the probable Facility for Borderline candidates over the test, in other words, the cut score for Borderline candidates. We describe ways of estimating C and F in any given circumstance, and suggest typical values arising from this particular study: that C = 12.3 and F = 0.021. Conclusions C and F are relatively stable, and that the equation y = 12.3.e0.021x can rapidly be applied to the item Facility for every item. The average value represents the cut score for the assessment as a whole. This represents a novel retrospective method based on test takers. Compared to the Cohen method which draws on one score and one candidate, this method draws on all items and candidates in a test. We propose that it can be used to standard set a whole test, or a particular item where the predicted Angoff score is very different from the observed Facility

PANC Study (Pancreatitis: A National Cohort Study): national cohort study examining the first 30 days from presentation of acute pancreatitis in the UK

Abstract Background Acute pancreatitis is a common, yet complex, emergency surgical presentation. Multiple guidelines exist and management can vary significantly. The aim of this first UK, multicentre, prospective cohort study was to assess the variation in management of acute pancreatitis to guide resource planning and optimize treatment. Methods All patients aged greater than or equal to 18 years presenting with acute pancreatitis, as per the Atlanta criteria, from March to April 2021 were eligible for inclusion and followed up for 30 days. Anonymized data were uploaded to a secure electronic database in line with local governance approvals. Results A total of 113 hospitals contributed data on 2580 patients, with an equal sex distribution and a mean age of 57 years. The aetiology was gallstones in 50.6 per cent, with idiopathic the next most common (22.4 per cent). In addition to the 7.6 per cent with a diagnosis of chronic pancreatitis, 20.1 per cent of patients had a previous episode of acute pancreatitis. One in 20 patients were classed as having severe pancreatitis, as per the Atlanta criteria. The overall mortality rate was 2.3 per cent at 30 days, but rose to one in three in the severe group. Predictors of death included male sex, increased age, and frailty; previous acute pancreatitis and gallstones as aetiologies were protective. Smoking status and body mass index did not affect death. Conclusion Most patients presenting with acute pancreatitis have a mild, self-limiting disease. Rates of patients with idiopathic pancreatitis are high. Recurrent attacks of pancreatitis are common, but are likely to have reduced risk of death on subsequent admissions. </jats:sec