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Biomedical subjects

J de Bie

Publications and source records attributed to J de Bie.

9 recordsLinked to original sources
PubMed2005

Risky procedures by nurses in hospitals: problems and (contemplated) refusals of orders by physicians, and views of physicians and nurses.

Occurrence of problems with, refusals of orders and contemplated refusals of orders for risky procedures by nurses in Dutch hospitals and views on the safety of performance was studied using postal questionnaires (600 physicians and 3200 nurses, response 60-71%). Of the respondents, 11-30% experienced problems with and (contemplated) refusals of orders for risky procedures in the previous 12 months. Gynaecologists and internists most frequently mentioned problems concerning the practical performance of the procedure (44% and 30%, respectively). The reason for a problem or a contemplated refusal most frequently given by nurses was that they disagreed with the medication policy (34% and 35%, respectively). The reason for a refusal most frequently given by the gynaecologists, internists and nurses was that the nurses themselves were of the opinion that they did not have the necessary authorisation (95%, 67%, and 62%, respectively). With regard to certain procedures, the views of professionals are more strict than the current legal regulations.

Attitude of Health Personnel↗
PubMed2005

Risky procedures by nurses in hospitals: problems and (contemplated) refusals of orders by physicians, and views of physicians and nurses: a questionnaire survey.

Occurrence of problems with, refusals of orders and contemplated refusals of orders for risky procedures by nurses in Dutch hospitals and views on the safety of performance was studied using postal questionnaires (600 physicians and 3200 nurses, response 60--71%). Of the respondents, 11--30% experienced problems with and (contemplated) refusals of orders for risky procedures in the previous 12 months. Gynaecologists and internists most frequently mentioned problems concerning the practical performance of the procedure (44% and 30%, respectively). The reason for a problem or a contemplated refusal most frequently given by nurses was that they disagreed with the medication policy (34% and 35%, respectively). The reason for a refusal most frequently given by the gynaecologists, internists, and nurses was that the nurses themselves were of the opinion that they did not have the necessary authorisation (95%, 67%, and 62%, respectively). With regard to certain procedures, the views of professionals are more strict than the current legal regulations.

Attitude of Health Personnel↗
PubMed2004

Reserved procedures in Dutch hospitals: knowledge, experiences and views of physicians and nurses.

The Individual Health Care Professions Act came into force in The Netherlands in 1997, introducing a mixed system for the regulation of the practice of medicine. One of its components, the reserved procedures regulations, was studied in hospitals to gain insight into the knowledge, experiences and views of physicians and nurses with regard to these regulations. Questionnaires were sent to representative samples of 250 gynaecologists, 350 internists, and 3200 nurses, response rates were 65, 60 and 71%, respectively. Almost all respondents were aware that physicians are authorised to perform reserved procedures on their own initiative (93-99%), and 48-63% knew that nurses are not authorised to do this. A substantial percentage of the nurses performed reserved procedures on their own initiative (17-53%). A majority of gynaecologists and internists presumed that the hospital had ensured the proficiency of the nurses to perform reserved procedures (58% resp. 65%), while 82% of the nurses determined their own proficiency for each procedure. Most respondents felt that the reserved procedures regulations offer adequate protection for patients (58-72%). Although recommendations are made for improvement, the functioning of the reserved procedures regulations in hospitals is considered to be moderately positive.

Attitude of Health Personnel↗
PubMed1996

Oxygen distributions partly explain the radiation response of human squamous cell carcinomas.

The oxygen tension of human tumours has often been thought to alter tumour response to radiation therapy. The purpose of this analysis is to determine to what extent the observed results of radiotherapy fit predictions based on in situ human tumour pO2 distributions. The radiation dose-response curve for patients treated with radiation alone for squamous cell cancers of the cervix and oropharynx were calculated based on published data. pO2 histograms were obtained from 30 women with cervical cancer and 11 patients with neck nodes from head and neck cancers. An average of 76 +/- 35 (range 28-174) measurements were made from each patient. Hypoxia was assumed to be a purely dose-modifying factor with a maximum OER of 2.5. Assuming patients are treated with daily radiation doses of 2 Gy, the squamous cell carcinoma alpha/beta ratio is 10 Gy, and that tumours have a mean of 10(8) clonogens, it was possible to estimate tumour control probability. Tumour oxygenation was an extremely important modifier of the slope of the dose-response curve and alone was sufficient to account for the slope of the clinically observed dose-response curve for neck nodes. The response curve for uterine cervical cancers is very shallow, and the oxygen distribution did not completely account for heterogeneity of response of these tumours. The results support the conclusion that oxygen tension distribution is an important modifier of human radiation treatment response.

Carcinoma, Squamous Cell↗
PubMed1993

Supine and standing sympathovagal balance in athletes and controls.

Differences in autonomic nerve activity between athletes and controls during supine rest and standing were investigated by recording the cardiac rhythm in 18 professional cyclists and 11 controls. We computed four indexes of autonomic control: the standard deviation (SD) of the interbeat intervals, the coefficient of variance (CV) of the interbeat intervals, the percentage of successive intervals differing by more than 50 ms (pNN50), and the fraction low-frequency (0.07-0.14 Hz) spectral power (LF), and we also measured the mean interbeat interval (MI). Significant differences (Student's t-test, P < 0.005) between the athletes and the controls in the supine position were found for pNN50 [mean 52.6 (SEM 2.5) vs 37.1 (SEM 3.4)%], LF [mean 32.2 (SEM 1.6) vs 40.7 (SEM 2.1) normalized units], and MI [mean 1241 (SEM 20) vs 1021 (SEM 25) ms]. A significant difference between the athletes and the controls in the standing position was found for MI [mean 888 (SEM 13) vs 801 (SEM 23) ms]. These results would suggest that there is a parasympathetic predominance in athletes in the supine, but not in the standing position. The finding that pNN50 and LF, but not SD and CV, differed between the athletes and the controls, would seem to demonstrate that the differences in autonomic control between the athletes and the controls are reflected in the quality (balance between slow and fast heart rate fluctuations) rather than in the quantity of heart rate variability.

Adult↗
PubMed1993

Methods in heart rate variability analysis: which tachogram should we choose?

We investigated the practical impact of the representation of the cardiac rhythm--the cardiotachogram--on two elementary spectral indexes in heart rate variability analysis: the low-frequency (0.07-0.14 Hz) and high-frequency (0.14-0.40 Hz) powers. Five commonly used tachograms (inter-beat interval function/series, counts, instantaneous heart rate function/series) were compared. Measurements were done on seven volunteers in the supine and standing positions. Ratios, and their deviations from 100%, of alternative power values were calculated. Mean low-frequency and high-frequency ratio deviations ranged from 0 to 5% and from 6 to 37%. The spectrum of counts yielded on average more (15-37%) high-frequency power. Spectra were incomparable without normalization of the tachogram with respect to heart rate. In conclusion, (i) the choice of a particular spectrum may lead to differing conclusions on the vagal contribution to heart rate variability and (ii) inconclusive results from studies using different tachogram variants can partly be due to the omission of normalization.

Adult↗
PubMed1986

A model for the slow control system during monocular fixation.

A method has been developed to compare the behaviour of the oculomotor control system during steady fixation and during reactions on small stimulus movements. No difference between the two conditions was found, and the reactions on small steps (1-5') and step/ramps (2-10'/sec), during normal and stabilized vision, have been used to develop a model for the slow control system during fixation. The model consists of a position channel, which integrates the retinal error, and a velocity channel, that uses both the retinal velocity and an efferent copy of the eye velocity. The model parameters have been estimated from the data of four subjects.

Eye Movements↗
PubMed1985

An afterimage vernier method for assessing the precision of eye movement monitors: results for the scleral coil technique.

A method is described to assess the precision of eye movement monitors by comparing the difference in two sequentially measured eye positions with the relative positions of afterimages that were induced at the same moments. A 0.1-0.3 min of arc sensitivity could be reached, using a vernier method. The precision of the scleral coil technique was 1 min of arc.

Afterimage↗