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Biomedical subjects

M A Johnston

Publications and source records attributed to M A Johnston.

At least 19 recordsLinked to original sources
PubMed2003

Rapid sequence intubation in Scottish urban emergency departments.

OBJECTIVE: Airway care is the cornerstone of resuscitation. In UK emergency department practice, this care is provided by anaesthetists and emergency physicians. The aim of this study was to determine current practice for rapid sequence intubation (RSI) in a sample of emergency departments in Scotland. METHODS: Two year, multicentre, prospective observational study of endotracheal intubation in the emergency departments of seven Scottish urban teaching hospitals. RESULTS: 1631 patients underwent an intubation attempt in the emergency department and 735 patients satisfied the criteria for RSI. Emergency physicians intubated 377 patients and anaesthetists intubated 355 patients. There was no difference in median age between the groups but there was a significantly greater proportion of men (73.2% versus 65.3%, p=0.024) and trauma patients (48.5% versus 37.4%, p=0.003) in the anaesthetic group. Anaesthetists had a higher initial success rate (91.8% versus 83.8%, p=0.001) and achieved more good (Cormack-Lehane Grade I and II) views at laryngoscopy (94.0% versus 89.3%, p=0.039). There was a non-significant trend to more complications in the group of patients intubated by emergency physicians (8.7% versus 12.7%, p=0.104). Emergency physicians intubated a higher proportion of patients with physiological compromise (91.8% versus 86.1%, p=0.027) and a higher proportion of patients within 15 minutes of arrival (32.6% versus 11.3%, p<0.0001). CONCLUSION: Anaesthetists achieve more good views at laryngoscopy with higher initial success rates during RSI. Emergency physicians perform RSI on a higher proportion of critically ill patients and a higher proportion of patients within 15 minutes of arrival. Complications may be fewer in the anaesthetists' group, but this could be related to differences in patient populations. Training issues for RSI and emergency airway care are discussed. Complication rates for both groups are in keeping with previous studies.

Adult↗
PubMed2002

The APTT response of pregnant plasma to unfractionated heparin.

Pregnancy is associated with a physiological increase in coagulation factors and heparin binding proteins; both can affect the activated partial thromboplastin time (APTT) in response to unfractionated heparin (UFH) invalidating the use of a non-pregnant APTT therapeutic range. We compared the anticoagulant response of UFH added in vitro to the plasma of 13 pregnant (third trimester) and 15 nonpregnant women to determine whether the measured APTT and antifactor Xa activities are lower in pregnancy. Increasing concentrations of UFH were added to platelet-poor plasma from each subject and the APTT and anti-factor Xa activity were measured. The amount of UFH which was reversibly bound and neutralised by plasma heparin binding proteins was assessed by comparing the anti-factor Xa activity before and after addition of low affinity heparin (LAH). Fibrinogen, von Willebrand factor antigen (vWF Ag) and factor VIII levels, were also measured. The APTT response, assessed by the slope of the regression line of log APTT versus added heparin concentration, was attenuated in pregnant plasma (0.76 s/U/mL versus 1.2 s/U/mL, p = 0.005) and was highly correlated to increased non-specific plasma protein binding (47% versus 35% p <0.01) and increased fibrinogen (5.1 g/L versus 2.8 g/L, p < 0.01) and factor VIII activity (2.7 U/mL versus 1.2 U/mL, p <0.01). Thus, to achieve the same heparin level, pregnant women require higher daily doses of UFH than non-pregnant women. However, if UFH dose adjustments during the third trimester are based upon a non-pregnant APTT therapeutic range, systematic overdosing of pregnant women will result, possibly increasing the risk of bleeding and osteoporosis.

Adult↗
PubMed2000

Synthesis of arene-soluble mixed-metal Zr/Ce, Zr/Y, and related [[Zr2(OiPr)9]LnX2]n complexes using the dizirconium nonaisopropoxide ligand.

The utility of polydentate monoanionic [Zr2(OiPr)9]- in generating arene-soluble, unsolvated, mixed-metal Zr/Ce and Zr/Y complexes is described. The synthesis of other mixed-metal zirconium lanthanide complexes was also studied to explore the relationship of metal size to structure. Lanthanide trihalides react in THF with KZr2(OiPr)9 to form unsolvated dimers, [[Zr2(OiPr)9]LnCl2]2, with the larger metals, Ln = Ce (1), Ho (2), Y (3), and unsolvated monomers, [Zr2(OiPr)9]LnCl2, with the smaller elements, Ln = Er (4), Yb (5). The synthesis of a monomeric iodide analogue, [Zr2(OiPr)9]TmI2, 6, by reduction of Zr2(OiPr)8(iPrOH)2 with TmI2(DME)3 is also reported. In all of these complexes, the [Zr2(OiPr)9]- subunit is tetradentate. 1-6 are compared with related cyclopentadienyl halide complexes to evaluate the special features of the dizirconium nonaisopropoxide ligand versus cyclopentadienide.

Journal Article↗
PubMed1999

Influences of adult attachment in exploration.

Research into the relationship between attachment quality in both children and adults suggests links with patterns of exploration; however, exploration has been operationalized differently in studies of adults and children. This study examined adults' patterns of exploration operationalized in terms of novelty seeking, curiosity, and impulsivity, as in studies of children. Analysis indicated avoidant adults reported significantly lower curiosity than did securely attached adults, while preoccupied subjects showed no differences from either secure or avoidant groups. As in studies of children, groups did not differ on measures of novelty seeking or impulsivity.

Adult↗
PubMed1998

Communication and the process of educational change.

In this chapter, the authors describe the role of communication in the process of curricular reform at the eight schools that participated in The Robert Wood Johnson Foundation's "Preparing Physicians for the Future: Program in Medical Education." The collective experience of these eight schools suggests that despite its general neglect in the discourse on educational innovation, good communication is a decisive element of any successful reform initiative. The authors focus this chapter on effective communication patterns for supporting educational reform. First, the authors discuss a four-stage model of change--recognizing the need for change, and planning, implementing, and institutionalizing change--and describe the role of communication in each of them. They outline the communication strategies needed to promote a sense of ownership among all participants; structures and mechanisms for supporting positive communication; and common lessons learned by all schools about successful communication.

Communication↗
PubMed1997

The pathogenesis of venous limb gangrene associated with heparin-induced thrombocytopenia.

BACKGROUND: Platelet-mediated arterial occlusion is a well-recognized cause of limb loss in patients with heparin-induced thrombocytopenia. However, the syndrome of distal ischemic necrosis complicating the deep venous thrombosis (venous limb gangrene) sometimes associated with heparin-induced thrombocytopenia has not been well characterized. OBJECTIVE: To study the pathogenesis of venous limb gangrene associated with heparin-induced thrombocytopenia. DESIGN: Characterization (based on descriptive and case-control studies) of a novel syndrome of limb loss and hypothesis testing by analysis of plasma samples. SETTING: Five university-associated hospitals in one medical community. PATIENTS: Clinical and laboratory records of 158 patients with heparin-induced thrombocytopenia were reviewed to identify patients with venous limb gangrene (n = 8), limb arterial thrombosis (n = 10), and uncomplicated deep venous thrombosis (n = 58). MEASUREMENTS: Clinical and laboratory factors associated with venous limb gangrene, including thrombin-antithrombin complexes and vitamin K-dependent procoagulant and anticoagulant factors. RESULTS: Warfarin treatment was more frequently associated with venous limb gangrene than with limb arterial thrombosis (8 of 8 patients compared with 3 of 10 patients; P = 0.004). The anticoagulant effect of warfarin seemed greater in the 8 patients with venous limb gangrene than in the 58 patients who did not develop gangrene (median International normalized ratio, 5.8 compared with 3.1; P < 0.001). Compared with plasma from controls, plasma from patients with venous limb gangrene had a higher ratio of thrombin-antithrombin complex to protein C activity during warfarin treatment. No hereditable abnormalities of the protein C anticoagulant pathway were seen in any patient. CONCLUSIONS: Warfarin treatment of deep venous thrombosis associated with heparin-induced thrombocytopenia is a possible cause of venous limb gangrene, perhaps because of acquired failure of the protein C anticoagulant pathway to regulate thrombin generation.

Adult↗
PubMed1996

A model for distributing teaching funds to faculty.

Teaching at medical schools has been supported principally through research and clinical income, but these resources have become more scarce, faculty have begun to look elsewhere for support of student teaching. Yale University School of Medicine has developed a model for distributing a portion of general revenue funds to departments based entirely on their faculty members' commitment to the teaching of undergraduate medical students. This model combines both a qualitative measure (effectiveness) and a quantitative measure (effort) to assess the commitments of faculty to teaching. Initial response has been primarily positive. Both faculty members and chairs have acknowledged that faculty should receive financial support for major teaching responsibilities. Although the amount of funding may not be proportional to the actual effort of faculty members, by apportioning tuition dollars for teaching Yale hopes to send a powerful message about its commitment to its teaching faculty and to its medical students.

Budgets↗
PubMed1996

Major paediatric trauma in Glasgow 1980-1989: implications for services.

The experience of major paediatric trauma presenting both directly and indirectly over ten years to a Paediatric Teaching Hospital is presented. Of the 185 patients assessed and treated in the Resuscitation Room, 131 were considered to have sustained significant trauma: 99 being admitted to the Intensive Therapy Unit and 32 transferred to the regional Neurosurgical centre. Road traffic accidents were responsible for the majority of serious injuries and eight of the 11 deaths, emphasising the need for further preventative measures. There were 95 interhospital transfers amongst the 131 patients judged to have sustained significant trauma. The potential benefits of centralisation of services to manage major paediatric trauma, in terms of both a reduction in interhospital transfers and early involvement of experienced staff, are proposed.

Adolescent↗
PubMed1993

Adder (Vipera berus) bites: a case report and review of the management for emergency medical personnel.

Few doctors working in the accident and emergency (A&E) department will have had experience in the management of adder (Vipera Berus) bites. While such events are uncommon, and rarely fatal, prompt correct management undoubtedly helps in reducing mortality and morbidity. Various isolated case reports (Watson & Harland, 1977; Gerard & Pugh, 1982; Jones & Clegg, 1985) and larger reviews (Reid, 1976; Pesson & Irestedt 1981; Hawley, 1988, 1990) have appeared in non A&E related journals. Following our own recent experience we felt it timely to report our case and review the management.

Animals↗
PubMed1991

Inactive renin levels in recurrent nephroblastoma.

A prospective study of four children with nephroblastoma has demonstrated elevation of plasma inactive renin levels at the time of detection of recurrent disease. Three of the four children had been shown to have elevated inactive renin levels at their initial presentation with primary nephroblastoma. These levels returned to normal following operation and chemotherapy. The observation provides further evidence that plasma inactive renin may be a useful tumour marker for nephroblastoma.

Child↗
PubMed1991

A process for developing a curriculum in ethics and human values.

This article describes the process and results of the deliberations of the group of authors at the 1989 spring meeting of the Northeast Group for Educational Affairs. The participants worked under the premise that someone had given an unlimited amount of money to fund a new medical school. They had to select and define what the educational goals would be and produce a plan to help students reach these goals. There had to be an evaluation process that documented progress toward the stated goals. This paper describes the ethics and human values curriculum, which should be of interest to cancer educators. The knowledge, skills, values, and attitudes are defined and the four-year process of implementing the teaching is described. This curriculum-planning process is applicable to any aspect of cancer education--first defining the outcome, then the evaluation process, and finally, how to get to that outcome.

Curriculum↗