| 1. |
- Reinstrup, Peter, et al.
(author)
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Cerebral blood volume (CBV) in humans during normo- and hypocapnia: influence of nitrous oxide (N(2)O)
- 2001
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In: Anesthesiology. - 1528-1175. ; 95:5, s. 1079-1082
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Journal article (peer-reviewed)abstract
- BACKGROUND: It is generally argued that variations in cerebral blood flow create concomitant changes in the cerebral blood volume (CBV). Because nitrous oxide (N(2)O) inhalation both increases cerebral blood flow and may increase intracranial pressure, it is reasonable to assume that N(2)O acts as a general vasodilatator in cerebral vessels both on the arterial and on the venous side. The aim of the current study was to evaluate the effect of N(2)O on three-dimensional regional and global CBV in humans during normocapnia and hypocapnia. METHODS: Nine volunteers were studied under each of four conditions: normocapnia, hypocapnia, normocapnia + 40-50% N(2)O, and hypocapnia + 40-50% N(2)O. CBV was measured after (99m)Tc-labeling of blood with radioactive quantitative registration via single photon emission computer-aided tomography scanning. RESULTS: Global CBV during normocapnia and inhalation of 50% O(2) was 4.25 +/- 0.57% of the brain volume (4.17 +/- 0.56 ml/100 g, mean +/- SD) with no change during inhalation of 40-50% N(2)O in O(2). Decreasing carbon dioxide (CO(2)) by 1.5 kPa (11 mmHg) without N(2)O inhalation and by 1.4 kPa (11 mmHg) with N(2)O inhalation reduced CBV significantly (F = 57, P < 0.0001), by 0.27 +/- 0.10% of the brain volume per kilopascal (0.26 +/- 0.10 ml x 100 g(-1) x kPa(-1)) without N(2)O inhalation and by 0.35 +/- 0.22% of the brain volume per kilopascal (0.34 +/- 0.22 ml x 100 g(-1) x kPa(-1)) during N(2)O inhalation (no significant difference). The amount of carbon dioxide significantly altered the regional distribution of CBV (F = 47, P < 0.0001), corresponding to a regional difference in Delta CBV when CO(2) is changed. N(2)O inhalation did not significantly change the distribution of regional CBV (F = 2.4, P = 0.051) or Delta CBV/Delta CO(2) in these nine subjects. CONCLUSIONS: Nitrous oxide inhalation had no effect either on CBV or on the normal CBV-CO(2) response in humans.
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| 2. |
- Bär, Olaf, et al.
(author)
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[Secondary prevention for police officers involved in job-related psychologically stressful or traumatic situations]
- 2004
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In: Zeitschrift für Psychosomatische Medizin und Psychotherapie. - 1438-3608. ; 50:2, s. 190-202
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Journal article (peer-reviewed)abstract
- OBJECTIVES: Police officers are at high risk of being exposed to psychologically straining situations and potentially psychotraumatic experiences. In this article, such situations are exemplified and categorized, and the role and significance of secondary prevention following traumatic experiences is discussed. METHODS: From 1994 to 2003, 649 police officers received secondary prevention after being involved in a total of 250 potentially traumatic or psychologically stressful incidents. Psychological support was provided by teams of specially trained professionals in the acute phase after the incident following careful psychological evaluation. In a retrospective evaluation, the diagnoses obtained were analyzed with regard to sex and age and correlated with the severity of the incident. Three clusters of potentially traumatic situations were formed: (1) Employment of fire-arms with danger for the officer, (2) Standard situations including violence towards a third party, (3) Suicide or attempted suicide of a police officer. RESULTS: Police officers who experienced events assigned to cluster (1), comprising situations with considerable traumatic potential, had the highest incidence of posttraumatic stress disorder (PTSD) or other mental illness. Compared to male officers, females were more often diagnosed with other mental illness, whereas males had a higher incidence of PTSD. Cluster (2), which comprised situations of an officer's daily professional life, was not associated with an increased risk of mental illness. Officers were apparently capable of coping with situations considered psychologically straining for the general public without detectable evidence of a traumatic reaction. In cluster (3), which reflects the most dramatic interference with team relations, other forms of mental illness were diagnosed at a higher incidence.
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| 3. |
- De Robertis, E, et al.
(author)
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Elastic properties of the lung and the chest wall in young and adult healthy pigs
- 2001
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In: European Respiratory Journal. - 1399-3003. ; 17:4, s. 703-711
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Journal article (peer-reviewed)abstract
- Understanding of the elastic pressure/volume (Pel/V) curve is still limited in health and disease. The aim of the present study was to elucidate the Pel/V curve and elastance of the respiratory system (ERS) lung (EL) and chest wall (ECW) in healthy pigs. Six young (20.8 kg) and seven adult (58.9 kg), anaesthetized, paralysed and ventilated pigs were studied. Pel/V curves were recorded at zero end-expiratory pressure (ZEEP) and at positive end-expiratory pressure (PEEP) up to 40 cmH2O with a computer controlled ventilator during an insufflation at a low, constant flow. Pel/V curves of the respiratory system showed a complex pattern in both young and adult pigs. During the insufflation, ERS decreased, increased, fell, and increased again. A second Pel/V curve recorded immediately after the first one showed lower elastance and only one early fall in ERS. ECW fell over the initial segment and was then nearly stable. Difference between 1st and 2nd curves reflected changes in EL caused by recruitment during the 1st insufflation. At PEEP, such signs of collapse and recruitment were reduced. A strong tendency to lung collapse contributes to a complex pattern of elastic pressure/volume curves. At low volumes and distending pressures the chest wall contributes significantly to changes in respiratory system elastance.
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