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Anesthetics, Inhalation↗
Biomedical subjects
L Schlünzen
Publications and source records attributed to L Schlünzen.
Effects of dose-dependent levels of isoflurane on cerebral blood flow in healthy subjects studied using positron emission tomography.
BACKGROUND: In this study, we tested the hypothesis that escalating drug concentrations of isoflurane are associated with a significant decline in cerebral blood flow (CBF) in regions sub-serving conscious brain activity, including specifically the thalamus. METHODS: Nine human volunteers received three escalating drug concentrations: 0.2, 0.4 and 1.0 MAC end-tidal inhalation. During waking, baseline and the three levels of sedation, aO PET scan was performed. RESULTS: Isoflurane decreased the bispectral index (BIS) values dose-dependently. Cardiovascular and respiratory parameters were maintained constant over time. No significant change in global CBF was observed. Throughout all three MAC levels of sedation, isoflurane caused an increased regional cerebral blood flow (rCBF) in the anterior cingulate and decreased rCBF in the cerebellum. Initially, isoflurane (0 vs. 0.2 MAC) significantly increased relative rCBF in the medial frontal gyrus and in the nucleus accumbens. At the next level (0.2 vs. 0.4 MAC), relative rCBF was significantly increased in the caudate nucleus and decreased in the lingual gyrus and cuneus. At the last level (0.4 vs. 1 MAC), relative rCBF was significantly increased in the insula and decreased in the thalamus, the cuneus and lingual gyrus. Compared with flow distribution in awake volunteers, 1 MAC of isoflurane significantly raised relative activity in the anterior cingulate and insula regions. In contrast, a significant relative flow reduction was identified in the thalamus, the cerebellum and lingual gyrus. CONCLUSIONS: Isoflurane, like sevoflurane, induced characteristic flow redistribution at doses of 0.2-1.0 MAC. At 1 MAC of isoflurane, rCBF decreased in the thalamus. Specific areas affected by both isoflurane and sevoflurane included the anterior cingulate, insula regions, cerebellum, lingual gyrus and thalamus.
Adult↗
Effects of subanaesthetic and anaesthetic doses of sevoflurane on regional cerebral blood flow in healthy volunteers. A positron emission tomographic study.
BACKGROUND: We tested the hypothesis that escalating drug concentrations of sevoflurane are associated with a significant decline of cerebral blood flow in regions subserving conscious brain activity, including specifically the thalamus. METHODS: Nine healthy human volunteers received three escalating doses using 0.4%, 0.7% and 2.0% end-tidal sevoflurane inhalation. During baseline and each of the three levels of anaesthesia one PET scan was performed after injection of . Cardiovascular and respiratory parameters were monitored and electroencephalography and bispectral index (BIS) were registered. RESULTS: Sevoflurane decreased the BIS values dose-dependently. No significant change in global cerebral blood flow (CBF) was observed. Increased regional CBF (rCBF) in the anterior cingulate (17-21%) and decreased rCBF in the cerebellum (18-35%) were identified at all three levels of sedation compared to baseline. Comparison between adjacent levels sevoflurane initially (0 vs. 0.2 MAC) decreased rCBF significantly in the inferior temporal cortex and the lingual gyrus. At the next level (0.2 MAC vs. 0.4 MAC) rCBF was increased in the middle temporal cortex and in the lingual gyrus, and decreased in the thalamus. At the last level (0.4 MAC vs. 1 MAC) the rCBF was increased in the insula and decreased in the posterior cingulate, the lingual gyrus, precuneus and in the frontal cortex. CONCLUSION: At sevoflurane concentrations at 0.7% and 2.0% a significant decrease in relative rCBF was detected in the thalamus. Interestingly, some of the most profound changes in rCBF were observed in structures related to pain processing (anterior cingulate and insula).
Adult↗
Cost consciousness among anaesthetic staff.
BACKGROUND: Anaesthetists, like all other specialists, need to be aware of the costs of drugs, fluids and disposables commonly used in their clinical practice so that excessive costs and waste can be minimized without compromising patient care or safety. The present study describes cost consciousness among 120 anaesthetic staff members in two Danish anaesthetic departments. METHOD: A prospective study questioning 120 anaesthetic staff members (69 anaesthetic nurses, 35 senior anaesthetists and 16 junior anaesthetists) about the costs of 29 drugs, fluids and disposable used in routine anaesthetic practice. RESULTS: After the study period 107 questionnaires (90%) were available for analysis. Thirty-eight percent of all estimated costs were within 50% of the actual costs and 85% were within 100%. The costs of relatively expensive items such as isoflurane, enflurane, sevoflurane and hydroxyethyl starch were consistently underestimated, whereas cheaper items such as narcotic drugs, endotracheal tubes, intravenous tubing, plastic syringes and Quincke spinal needle were consistently overestimated. In general, the anaesthetic staff overestimated the costs by 69% (range -24% to 270%). The anaesthetic nursing group overestimated the costs by 49% (range -24% to 270%), junior anaesthetists by 94% (range 25% to 226%) and senior anaesthetists by 72% (range -14% to 135%). CONCLUSION: This study shows that the overall consciousness of the costs of anaesthetic drugs, fluids and disposables has to be improved in order to permit the staff to optimize resources.
Anesthesia↗
[Mechanical ventilation in acute respiratory insufficiency in patients with chronic obstructive lung diseases].
Chronic obstructive lung disease (COLD) is a common disease and cause of death. At an advanced stage, acute respiratory failure will repeatedly arise and mechanical ventilation may be the only solution. The best result of treatment is a return to the habitual condition. In this article a survey is presented regarding the course and survival following mechanical ventilation of acute exacerbation of COLD. Survival rate after mechanical ventilation was 50-70% compared to a survival rate of 75-95% in patients not mechanically ventilated. Mechanical ventilation influenced factors were taken into consideration. The severity of baseline COLD and comorbidity had significant influence on survival. These factors together with the quality of nursing were predictors of successful ventilator weaning. Knowledge of the patient before the need for mechanical ventilation arises is of decisive importance.
Acute Disease↗
Convective warming blankets improve peroperative heat preservation in congenital heart surgery.
Peroperative heat preservation, following hypothermic cardiopulmonary bypass (CPB) in children, has always been a challenge to the anaesthetist. We studied the efficiency of a convective heating system on peroperative heat preservation in 50 children undergoing congenital heart surgery. Twenty-five children, rewarmed by CPB and heating mattress, were randomly selected (Group 1). Another 25 children, rewarmed by CPB, heating mattress and convective warming blankets in addition (Group 2), were selected so the two groups were comparable regarding age, weight and anaesthetic management. The central and peripheral temperatures were measured during bypass, at the end of bypass and at the end of operation. A retrospective evaluation showed that during bypass the peripheral temperature was significantly lower in Group 2 than in Group 1, with no significant difference in central temperature. At the end of bypass there was no significant difference between the two groups. At the end of operation the central and peripheral temperatures were significantly higher in Group 2. In conclusion convective warming blankets are effective in keeping or even raising the temperature following congenital heart surgery.
Body Temperature↗
Modified ultrafiltration in paediatric cardiac surgery.
The effect of modified ultrafiltration (MUF) after cardiopulmonary bypass for paediatric cardiac surgery was evaluated in 138 children with moderate to severe congenital heart disease. The median age was 0.4 years (0 days to 6.5 years), and the weight 5.3 kg (2.2-20 kg). The operation was discontinued in six cases, three because of technical problems and three because of unstable circulation. One-hundred-and-thirty-four patients were ultrafiltrated for a median of 12 min (2-27 min) with an ultrafiltrate of median 44 ml/kg (6-118 ml/kg). Haematocrit was significantly increased from 28% (20-39%) to 36% (26-51%) and systolic arterial pressure from 56 mmHg (30-85 mmHg) to 74.0 mmHg (32-118 mmHg). Furthermore arterial oxygenation was significantly increased from 30.8 kPa (4.8-70.4 kPa) to 34.1 kPa (4.9-80.6 kPa), and arterial carbon dioxide tension from 4.8 kPa (3.1-7.3 kPa) to 5.1 kPa (3.1-7.6 kPa). Heart rate was significantly reduced from 145 beats/min (92-201 beats/min) to 136 beats/min (88-200 beats/min). There were no significant differences in central venous pressure, left atrial pressure and base excess before and after MUF. MUF increases systolic blood pressure, haematocrit, arterial oxygen and carbon dioxide tension coming off bypass in paediatric cardiac surgery and reduces heart rate and postoperative fluid overload.
Cardiac Surgical Procedures↗
[Outbreak of methicillin resistant Staphylococcus aureus in a central hospital].
Until 1994, methicillin resistant Staphylococcus aureus (MRSA) were isolated from less than 60 patients annually in Denmark. We describe an outbreak of MRSA involving eight patients within a timespan of six weeks. Bacteriophage-typing and DNA typing using pulsed field gel electrophoresis revealed that three different strains of MRSA were involved in the outbreak. This emphasizes the importance of typing MRSA in order to clear up the spread in an outbreak. Of the eight patients four died, and in one case MRSA was thought to be the major cause of death. The expenses of the extra hygienic measures i.e. isolation of patients, medication and bacteriological surveillance were estimated to approximately DKK 80.000 pr. patient. Patients, who have been admitted to or worked at a hospital outside Scandinavia within the last six months, are potentially colonized with MRSA. Specific guidelines for hospital hygiene are necessary to prevent the spread of such strains.
Adult↗