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Biomedical subjects

Malcolm Fisher

Publications and source records attributed to Malcolm Fisher.

7 recordsLinked to original sources
PubMed2006

The prevention of anaphylactoid reactions to iodinated radiological contrast media: a systematic review.

BACKGROUND: Anaphylactoid reactions to iodinated contrast media are relatively common and potentially life threatening. Opinion is divided as to the utility of medications for preventing these reactions. We performed a systematic review to assess regimes for the prevention of anaphylactoid reactions to iodinated contrast media. METHODS: Searches for studies were conducted in the Medline, EMBASE, CINAHL and CENTRAL databases. Bibliographies of included studies and review articles were examined and experts were contacted. Randomised clinical trials that examined agents given prior to iodinated contrast material for the prevention of anaphylactoid reactions were included in the review. The validity of the included studies was examined using a component approach. RESULTS: Six studies met the inclusion criteria, but only one of these fulfilled all of the validity criteria. There were four studies that examined the use of H1 antihistamines, each was used to prevent anaphylactoid reactions to ionic contrast. The random effects pooled relative risk demonstrated a significant reduction in the overall rate of anaphylactoid reactions (RR = 0.4, 95% CI 0.18-0.9, p = 0.027). There were insufficient studies to produce a pooled statistic for the use of corticosteroids, however regimes of steroids (methylprednisolone 32 mg) given at least six hours and again two hours prior to the administration of contrast suggested a reduction in the incidence of anaphylactoid reactions. CONCLUSION: In conclusion, there are few high quality randomised clinical trials that have addressed the question of the optimal methods to prevent allergic type reactions to iodinated radiological contrast media. Allowing for these limitations, the results suggest that H1 antihistamines given immediately prior to the administration of ionic contrast may be useful in preventing reactions to ionic contrast and are suggestive of a protective effect of corticosteroids when given in two doses at least six hours prior and again two hours prior to the administration of contrast, both ionic and non-ionic. These agents should be considered for use in patients who are at high risk of an anaphylactoid reaction to contrast media and for who prophylactic therapy is considered necessary. Further research is needed before definitive recommendations can be made.

Journal Article↗
PubMed2004

Ethics roundtable debate: withdrawal of tube feeding in a patient with persistent vegetative state where the patients wishes are unclear and there is family dissension.

The decision to withdraw or withhold life supporting treatment in moribund patients is difficult under any circumstances. When the patient becomes incompetent to clarify their wishes regarding continued maintenance in long-term facilities, surrogates sometimes cannot agree, further clouding the issue. We examine a case where the State's interests come into play, forcing a controversial resolution.

Adult↗
PubMed2004

Anaphylaxis to anaesthetic drugs.

Severe anaphylactic reactions during anaesthesia increased dramatically in incidence in the mid 1970s. Studies performed in our unit over the subsequent 25 years demonstrated the involvement of IgE in these reactions and the value and safety of intradermal and prick testing in the diagnosis and determination of the drug responsible. Radioimmunoassay studies demonstrated that neuromuscular blocking drugs produce anaphylaxis by cross-linking IgE molecules via their substituted ammonium groups. The IgE binding of these drugs leads to a high incidence of cross sensitivity. Mast cell tryptase measurement is highly sensitive and specific for anaphylaxis although it can be elevated in reactions due to direct histamine release. The reactions are unpredictable from the history. The heart is rarely a target organ in human anaphylaxis although the diseased heart is more likely to fail or produce serious arrhythmias than the normal heart. Colloid solutions produce a better response than crystalloid solutions in the treatment of hypotension. Anaesthetic allergy persists up to 27 years. Subsequent anaesthesia based on the findings of skin testing is usually safe.

Anaphylaxis↗
PubMed2003

Influence of perceived functional and employment status on cardiopulmonary resuscitation directives.

BACKGROUND: Perceptions about functional and employment status before admission to the intensive care unit (ICU) may influence how patients and clinicians make decisions about cardiopulmonary resuscitation. OBJECTIVE: To examine the relationship between cardiopulmonary resuscitation directives established within 24 hours of admission to the ICU and clinical perceptions of premorbid functional and employment status. DESIGN: Prospective observational study in 15 university-affiliated centers in Canada, the United States, Australia, and Sweden. PATIENTS: A total of 1,008 ICU patients aged 18 years or older expected to stay in the ICU at least 72 hours. MEASUREMENTS: By using multinomial logistic regression, we examined the relationship between functional status and employment status perceived by the ICU team 1 month before ICU admission (the independent variables) and resuscitation status (the dependent variable). Each patient had either an explicit resuscitation directive (to resuscitate or not to resuscitate), or an implicit resuscitation directive to resuscitate. RESULTS: On average, patients were 61.7 years (+/-17.4 y) old with an Acute Physiology and Chronic Health Evaluation (APACHE) II score of 21.5 (+/-8.7); 846 (83.9%) were ventilated mechanically within 48 hours and 345 (34.2%) died in the ICU. Most patients (793, 78.7%) had no explicit resuscitation directive; 98 (9.7%) had an explicit plan to resuscitate, whereas 117 (11.6%) had an explicit plan of do-not-resuscitate. Of 1,008 patients, 98 (9.7%) were severely functionally limited, 217 (21.5%) were somewhat limited, 628 (62.3%) were totally independent, and 65 (6.4%) had unknown functional status 1 month before ICU admission. Severe functional status impairment was associated moderately with an explicit plan to resuscitate (odds ratio, 2.2 relative to no explicit directive) and associated strongly with an explicit do-not-resuscitate plan (odds ratio, 6.2 relative to no explicit directive, P value on the difference =.011). This relationship was not influenced by age, sex, APACHE II score, medical or surgical status, admission diagnosis, employment status, or city. However, severe functional status was associated strongly and significantly with an explicit do-not-resuscitate directive among those who could not participate in decision making (odds ratio, 8.2; 95% confidence interval, 4.5-15.0), and more weakly associated in those who could participate (odds ratio, 1.7; 95% confidence interval, 0.3-8.6). Being unemployed was associated with an increased odds of an explicit resuscitation directive versus no explicit directive (odds ratio, 5.5; 95% confidence interval, 2.2-13.4). CONCLUSIONS: Functional status impairment perceived by the ICU team is associated clearly with do-not-resuscitate directives in patients unable to participate in decision making. However, the association appears much weaker in patients able to participate in decision making. PATIENTS' perceived employment status also may influence resuscitation decisions. Our results emphasize the challenges of ensuring that crucial resuscitation decisions are not affected adversely by patients' inability to participate in decisions, and by their functional and employment status.

APACHE↗
PubMed2002

ICU Cornestone: a lecture that changed my practice.

In 1982, the author attended a lecture by Professor Joseph Civetta dealing with the concept that, at times, the goal of care should be comfort rather than cure, and that inappropriate care prolonged dying and suffering. Efforts to improve end-of-life care subsequent to this had effects on care at a local level and at a state level. Intensive care providers should be leaders in the provision of appropriate and compassionate care at the end of life.

Attitude of Health Personnel↗