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Biomedical subjects

B Husum

Publications and source records attributed to B Husum.

At least 19 recordsLinked to original sources
PubMed2005

Allergic reactions in anaesthesia: are suspected causes confirmed on subsequent testing?

BACKGROUND: The aim of this retrospective survey of possible allergic reactions during anaesthesia was to investigate whether the cause suspected by anaesthetists involved corresponded with the cause found on subsequent investigation in the Danish Anaesthesia Allergy Centre (DAAC). METHODS: Case notes and anaesthetic charts from 111 reactions in 107 patients investigated in the DAAC were scrutinized for either suspicions of or warnings against specific substances stated to be the cause of the supposed allergic reaction. RESULTS: In 67 cases, one or more substances were suspected. In 49 of these (73%) the suspected cause did not match the results of subsequent investigation, either a different substance being the cause or no cause being found. Only five cases (7%) showed a complete match between suspected cause and investigation result. In the remaining 13 cases (19%) there was a partial match, the right substance being suspected, but investigations showed an additional allergen or several substances, including the right substance being suspected. CONCLUSIONS: An informed guess is not a reliable way of determining the cause of a supposed allergic reaction during anaesthesia and may put a significant number of patients at unnecessary risk. Some patients may be labelled with a wrong allergy, leading to unnecessary warnings against harmless substances, and some patients may be put at risk of subsequent re-exposure to the real allergen. Patients with suspected allergic reactions during anaesthesia should be referred for investigation in specialist centres whenever possible.

Allergens↗
PubMed2003

Is there a risk of sensitization and allergy to chlorhexidine in health care workers?

BACKGROUND: In Denmark, chlorhexidine is the standard disinfectant in most hospitals and health care workers are repeatedly exposed to it. The aim of this study was to establish whether there is a risk of sensitization and allergy to chlorhexidine from this type of exposure. METHODS: Two hundred and forty-eight doctors, nurses and auxiliary staff were invited to participate in the study. One hundred and four individuals took part in the full study including skin tests and a questionnaire and a further 74 individuals filled in the questionnaire giving a total of 178 questionnaires (72%). Patch tests with chlorhexidine gluconate 1% and chlorhexidine acetate 1% were performed looking for type IV (delayed type) allergy. A prick test with chlorhexidine gluconate 0.5% and an intradermal test with chlorhexidine 0.0002% were performed looking for type I (immediate type) allergy. RESULTS: There were no positive tests in any of the 104 individuals tested (99% confidence interval 0-4.9%). There was a predominance of females in both groups and the overall median age was 42 years (28-63). No one in the group not tested reported to have a verified or suspected allergy to chlorhexidine. CONCLUSION: In this first study to examine the risk of type I and type IV allergy to chlorhexidine in health care workers with daily exposure to chlorhexidine, we did not identify allergies to chlorhexidine in any of the 104 individuals tested or in the additional 74 individuals who completed the questionnaire. We conclude that an allergy to chlorhexidine in health care workers is likely to be rare.

Adult↗
PubMed2002

Mortality among anesthesiologists in Denmark, 1973-95.

BACKGROUND: Preliminary data from Sweden indicating that anesthesiologists have a high mortality risk has caused a lot of concern in Denmark. The aim of this study therefore was to compare mortality between consultant anesthesiologists and other consultants in Denmark. METHODS: A historical prospective cohort study based on the membership register of the Danish Medical Association from 1973 to 1992. The study population consisted of 6854 consultants who were members of the Association of Medical Specialists, 406 of whom were anesthesiologists. The all-cause mortality between the two groups was compared during the period 1972-95 using Cox's proportional hazard regression model. RESULTS: The study covered approximately 86000 person-years. A total of 1205 deaths occurred within the period studied, 41 of whom were anesthesiologists. The relative risk for all-cause mortality among the anesthesiologists compared with all the other consultants was 1.0 (95% confidence limit: 0.7-1.4). CONCLUSION: In Denmark there is no evidence of a high mortality risk in consultant anesthesiologists compared with other consultants.

Adult↗
PubMed2001

Danish Anaesthesia Allergy Centre - preliminary results.

BACKGROUND: Anaphylactoid reactions in anaesthesia are rare and should ideally be investigated in specialist centres. At Gentofte University Hospital, we established such a centre in 1998 as a joint venture between the Departments of Anaesthesiology and Dermatology. We present the methodology, diagnostic algorithm and preliminary results from our centre. METHODS: We are open for referral of patients from all of Denmark. Reactions are classified using a three-grade severity scale and all reactions ranging from mild to severe are investigated. Investigations follow a standard step-by-step protocol of in vitro testing and skin testing. Blood samples for tryptase analysis are taken at the time of reaction and a control sample is taken together with samples for specific IgE analysis 2-4 weeks after the reaction. Subsequent skin testing comprises both prick tests and intradermal tests in most cases. Patients are tested with all substances they were exposed to, including antibiotics, colloids, latex and chlorhexidine. RESULTS: A total of 68 patients have been referred to date (July 2001) and 36 have completed investigations. Positive test results were mainly seen in patients with more severe reactions, and there were more men than women in the group with the most severe reactions. Six patients had positive specific IgE, three for penicillin, two for latex and one for thiopental. In all, 21 patients had positive skin tests to various substances, of whom four men with anaphylactic shock tested positive for chlorhexidine. Only one patient has tested positive to a neuromuscular blocking drug (NMBD) so far. DISCUSSION: Our preliminary results appear to differ in two ways from results usually found in this field. Firstly, only one patient has tested positive for a NMBD and secondly, we have had four patients with anaphylactic shock who have tested positive for chlorhexidine. Possible reasons for these differences are discussed.

Adolescent↗
PubMed2001

Anaphylactic reactions in anaesthetised patients - four cases of chlorhexidine allergy.

Chlorhexidine is widely used all over the world in many different preparations. In Denmark chlorhexidine is the standard skin disinfectant used before surgery or invasive procedures and it is widely used in the general population in mouthwash or for disinfection of minor scratches etc. The potential for developing allergy to chlorhexidine is thus great, especially in surgical patients. We have identified four patients with serious allergic reactions in connection with surgery and general anaesthesia, who on subsequent skin testing tested positive for chlorhexidine. Symptoms appeared 20-40 min into the operation and all four patients required treatment with adrenaline. All four patients had a history of minor symptoms like rashes or faints in connection with previous surgery/invasive procedures. Allergy to chlorhexidine may be more prevalent in surgical patients and cases may have been overlooked due to the nature of reactions and lack of suspicion towards this substance.

Aged↗
PubMed1994

Arterial line filtration protects brain microcirculation during cardiopulmonary bypass in the pig.

Microemboli in the brain may inhibit brain function during cardiopulmonary bypass, and in a previous study in pigs of normothermic nonpulsatile bypass we reported a significant decrease in cerebral glucose consumption secondary to interruption of the capillary flow, possibly caused by microemboli. In the present study we measured the regional cerebral glucose consumption and the regional capillary diffusion capacity (that is, the number of perfused capillaries) in 10 different brain regions in two separate groups of animals with and without an arterial filter during normothermic cardiopulmonary bypass. Inclusion of a 40 micron arterial filter in the bypass circuit increased the regional brain glucose consumption 27% (median; range -12% to 145%) and regional capillary diffusion capacity increased 123% (median; range 36% to 829%). No change in brain histologic features, the cerebrovascular permeability to serum proteins, or cerebral water content was observed. The arterial filter probably protects the cerebral microcirculation and prevents the decrease in cerebral glucose consumption otherwise seen during bypass.

Animals↗
PubMed1991

Sister-chromatid exchanges in cannabis smokers.

The genotoxicity of cannabis smoking was evaluated by means of the sister-chromatid exchange (SCE) test. The SCE test is considered to be a sensitive tool for the discovery of genotoxic agents in the environment. Twenty-two tobacco smokers and 22 persons smoking both tobacco and cannabis were compared. Our findings showed that smoking in itself enhanced the SCE level significantly (18.5%) compared to a group of non-smokers, but adding smoking of cannabis to tobacco smoking did not affect the SCE level further. Based on our observations cannabis smoking could not be considered genotoxic.

Adolescent↗
PubMed1989

Brain histology, blood-brain barrier and brain water after normothermic and hypothermic cardiopulmonary bypass in pigs.

The effect of hypothermia during cardiopulmonary bypass (CPB) on cerebral histopathology, blood-brain barrier permeability to serum proteins and water content was evaluated. Pigs were subjected to non-pulsatile CPB for 2 h at either normothermia or hypothermia, and a group of anaesthetised pigs served as normothermic controls. The histopathology was assessed on paraffin embedded sections. The permeability of the cerebral vessels was studied by immunocytochemical demonstration of extravasated serum proteins. The cerebral water content was assessed by specific gravity measurements. The histological studies demonstrated hydropic degeneration of the brain parenchyma and perivascular swelling of the astrocytic endfeet throughout both white and gray matter in the normothermic CPB group. Similar changes were not encountered during hypothermic CPB, which suggests a beneficial effect of decreased temperatures on brain tissue during CPB. Neither normothermic nor hypothermic CPB induced significant changes in the cerebrovascular permeability or in the specific gravities.

Animals↗
PubMed1989

Regional cerebral blood flow and glucose utilization during hypocapnia and adenosine-induced hypotension in the rat.

Hypocapnia and induced hypotension have been claimed by some to cause cerebral hypoxia because of insufficient perfusion. Regional cerebral blood flow (rCBF) and regional cerebral glucose utilization (rCMRglc) were measured simultaneously in the same animal subjected to hypocapnia or hypocapnia combined with induced arterial hypotension. The rCMRglc was measured with (3H) deoxyglucose and the rCBF with (14C) iodoantipyrine with the use of tissue biopsy methods and scintillation counting. Nineteen male Wistar rats were anesthetized with halothane and artificially ventilated. Anesthesia was maintained with nitrous oxide/oxygen (70:30) and succinylcholine. Six rats were maintained at normocapnia, six rats were ventilated to a PaCO2 of 20 mmHg, and seven animals were ventilated to PaCO2 20 mmHg combined with arterial hypotension of 50 mmHg (mean blood pressure) induced by infusion of adenosine. Although hypocapnia alone did not cause a statistically significant decrease of rCBF except in hippocampus, hypocapnia combined with hypotension resulted in a significant reduction of rCBF in four of seven regions when compared with hypocapnia alone; rCMRglc values were unchanged during hypocapnia. However, the addition of hypotension induced by adenosine led to a significant decline of glucose utilization in five of seven brain regions. In the present study the authors observed no increase of regional glucose utilization and hence no signs of cerebral ischemia during hypocapnia alone or combined with hypotension induced by adenosine.

Adenosine↗
PubMed1989

Hypocapnia prevents the decrease in regional cerebral metabolism during isoflurane-induced hypotension.

In neurologic surgery, induced hypotension is often used while the patient is hypocapnic. We investigated, by tissue biopsy methods and scintillation counting, the regional cerebral glucose utilization (rCMRglc) and blood flow (rCBF) in rats subjected to hypocapnia alone and in combination with hypotension. Anesthesia was maintained with 1.0% isoflurane in nitrous oxide/oxygen. Seven rats were maintained at PaCO2 of 40 mm Hg, six rats were ventilated to PaCO2 of 20 mm Hg, and six animals to PaCO2 of 20 mm Hg in combination with arterial hypotension of 50 mm Hg induced by isoflurane 2.5-3.5%. During hypocapnia, rCMRglc tended to increase in all regions, but the increase was statistically insignificant; rCBF was reduced uniformly by 40%. During combined hypocapnia/hypotension, rCMRglc was unaltered when compared to hypocapnia; compared to normocapnia, increases were seen in hippocampus and cerebellum. During hypocapnia/hypotension, rCBF was unaltered in cortical areas, while increases were seen in all subcortical areas compared to hypocapnia. Regional values of the ratio of rCBF/rCMRglc indicated that during hypocapnia and hypotension induced by isoflurane in nitrous oxide/oxygen, the individual brain areas were perfused according to their metabolic needs. It is suggested that hypocapnia may prevent the decrease in rCMRglc, which is usually observed during deep isoflurane anesthesia.

Journal Article↗
PubMed1987

Mutagenicity of inhalation anaesthetics studied by the sister chromatid exchange test in lymphocytes of patients and operating room personnel.

Retrospective studies have indicated that operating room personnel may have increased risks of spontaneous abortion, congenital malformations in offspring, and cancer (Cohen et al 1980, Buring et al 1985). Occupational exposure to waste anaesthetic gases may be responsible for these possible adverse health effects, but a cause-effect relationship has never been proved. Induction of changes in the DNA in the chromosomes leading to mutations may play a role in teratogenicity and carcinogenicity. Along with an increasing concern in society regarding occupational diseases and working and living environment in general, cytogenetic methods have been developed for rapid detection of potential mutagenicity in vitro of chemical agents. One such method is the SCE test, which is based on examination of sister chromatid exchanges (SCEs), i.e. exchanges of chromatid-segments between the two chromatids in a chromosome, during cell replication. SCEs are not mutations, but an increased frequency of SCE is a sensitive indicator of exposure to agents that are capable of producing damage to the DNA and thus possibly mutations. In vitro tests like the SCE test are very useful for evaluation of specific chemical agents, which may be added to the culture in known concentrations. In studies of possible hazards from chemical agents in the working or living environment, the exposure is often poorly defined. Also, biotransformation may be different in different species, and the duration and the level of the exposure may play a role. Examination of SCEs is, therefore, increasingly performed directly on human lymphocytes from peripheral blood. Thus, although the examination of SCEs is still performed in vitro, the exposure has taken place in vivo. Increased SCE levels are then regarded as a non-specific indicator that the donor has been exposed to potentially mutagenic agents in the environment. The author and his associates used the SCE test to investigate the possible mutagenicity of anaesthetic gases after exposure in vivo. From extensive methodologic studies of possible confounding factors it was concluded that each of the factors sex, age, and smoking habits contributed significantly to the interpersonal variation of SCE frequencies, whereas use of oral contraceptives did not influence the SCE rates. The potential mutagenicity of inhalation anaesthetics was studied after exposure in vivo in two settings: (1) Acute exposure to anaesthetic concentrations, and (2) Chronic occupational exposure to trace concentrations.(ABSTRACT TRUNCATED AT 400 WORDS)

Allied Health Personnel↗
PubMed1987

Brain microvascular function during cardiopulmonary bypass.

Emboli in the brain microvasculature may inhibit brain activity during cardiopulmonary bypass. Such hypothetical blockade, if confirmed, may be responsible for the reduction of cerebral metabolic rate for glucose observed in animals subjected to cardiopulmonary bypass. In previous studies of cerebral blood flow during bypass, brain microcirculation was not evaluated. In the present study in animals (pigs), reduction of the number of perfused capillaries was estimated by measurements of the capillary diffusion capacity for hydrophilic tracers of low permeability. Capillary diffusion capacity, cerebral blood flow, and cerebral metabolic rate for glucose were measured simultaneously by the integral method, different tracers being used with different circulation times. In eight animals subjected to normothermic cardiopulmonary bypass, and seven subjected to hypothermic bypass, cerebral blood flow, cerebral metabolic rate for glucose, and capillary diffusion capacity decreased significantly: cerebral blood flow from 63 to 43 ml/100 gm/min in normothermia and to 34 ml/100 gm/min in hypothermia and cerebral metabolic rate for glucose from 43.0 to 23.0 mumol/100 gm/min in normothermia and to 14.1 mumol/100 gm/min in hypothermia. The capillary diffusion capacity declined markedly from 0.15 to 0.03 ml/100 gm/min in normothermia but only to 0.08 ml/100 gm/min in hypothermia. We conclude that the decrease of cerebral metabolic rate for glucose during normothermic cardiopulmonary bypass is caused by interruption of blood flow through a part of the capillary bed, possibly by microemboli, and that cerebral blood flow is an inadequate indicator of capillary blood flow. Further studies must clarify why normal microvascular function appears to be preserved during hypothermic cardiopulmonary bypass.

Animals↗