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M Ragaller

Publications and source records attributed to M Ragaller.

31 records · Page 2Linked to original sources
PubMed2000

Electroencephalogram silence ratio for early outcome prognosis in severe head trauma.

OBJECTIVE: To introduce the electroencephalogram silence-ratio (ESR) as a variable derived from mathematically processed electroencephalogram for early outcome prognosis in patients with severe head trauma and to comparatively assess sensitivity, specificity and predictive value vs. somatosensory evoked potentials and brainstem auditory evoked potentials. DESIGN: Prospective, interventional study. SETTING: Intensive care unit of a university hospital. PATIENTS: A total of 32 adults with severe acute head trauma (Glasgow Coma Scale score < or = 8). METHODS AND MAIN RESULTS: In all patients, electroencephalographic recording was continuously performed by frontomastoid electrode montage for 24-96 hrs after admission to the ICU. The data were subsequently computed by fast Fourier analysis and the ESR (intervals of suppression as periods >240 msecs during which the electroencephalographic voltage did not exceed 5 microV) was displayed and recorded on a computer for further evaluation. Somatosensory evoked potentials and brainstem auditory evoked potentials were elicited during the first 2 days after admission. Outcome evaluation was performed 6 months after trauma using the Glasgow Outcome Scale and the Rappaport Disability Rating Scale. After careful artifact exclusion, the ESR depicted the highest sensitivity, specificity, and positive predictive value compared with evoked potentials. Even a highly significant correlation between outcome and ESR was found (p < .0001). CONCLUSION: The ESR is a valuable variable showing a high reliability with respect to outcome prediction in severe head trauma with a higher predictive value than short latency somatosensory evoked potentials. Evidence exists that the ESR provides at least partial information regarding adequate cerebral oxygen delivery.

Activities of Daily Living↗
PubMed2000

Hemodynamic effects of hypertonic hydroxyethyl starch 6% solution and isotonic hydroxyethyl starch 6% solution after declamping during abdominal aortic aneurysm repair.

Fluid resuscitation with hypertonic hydroxyethyl starch solutions (HES) is effective in haemorrhagic shock due to the rapid mobilisation of fluids into the intravascular compartment. Declamping of the abdominal aorta with acute redistribution of blood into the vessels of the lower body half causes declamping-induced hypotension. Usually large amount of fluids or vasopressors are necessary to restore hemodynamic stability. Therefore, infusion of a hypertonic colloid solution may be an attractive option to achieve hemodynamic stability. This study was conducted to determine the amount of fluid of either hypertonic HES (HES 6%;7.2% NaCl) or isotonic HES (HES 6%;0.9% NaCl) needed to attain best wedge pressure (PCWP) cardiac index (CI) relation after declamping. Thirty-two high-risk patients undergoing elective abdominal aneurysm resection were enrolled in a prospective, randomised, double blinded study. The individual optimised PCWP/CI relation was determined after induction of anaesthesia. After declamping, both solutions were titrated in small boluses of 100 mL until the previously determined best wedge was reached. The amount of fluid after declamping was significantly reduced in the hypertonic HES- group 162 mL vs. 265 mL in the control group (P < 0.05). Resuscitation time was shortened, and cardiac index was slightly higher in the treatment group. The use of hypertonic HES-solution after aortic declamping led to a significant reduction of fluids necessary to attain optimised PCWP/CI relation. In this clinical trial with moderate blood loss in high-risk patients, hypertonic HES applied in a titrated fashion restored hemodynamic stability faster and without volume overload.

Aged↗
PubMed2000

Functional recovery despite prolonged bilateral loss of somatosensory evoked potentials: report on two patients.

A bilateral loss of short latency somatosensory evoked potentials (SSEPs) after head trauma or non-traumatic brain damage is normally associated with a deleterious neurological outcome. An adequate recovery in reported in two deeply comatose patients with head trauma or severe hypertensive encephalopathy despite prolonged bilateral loss of SSEPs over days, found in repeated recordings. Hence, a bilateral loss of SSEPs should not be considered alone for prediction of outcome in cerebral injury.

Adult↗
PubMed1999

Vaporized perfluorocarbon improves oxygenation and pulmonary function in an ovine model of acute respiratory distress syndrome.

BACKGROUND: Perfluorocarbon liquids are being used experimentally and in clinical trials for the treatment of acute lung injury. Their resemblance to inhaled anesthetic agents suggests the possibility of application by vaporization. The authors' aim was to develop the technical means for perfluorocarbon vaporization and to investigate its effects on gas exchange and lung function in an ovine model of oleic acid-induced lung injury. METHODS: Two vaporizers were calibrated for perfluorohexane and connected sequentially in the inspiratory limb of a conventional anesthetic machine. Twenty sheep were ventilated in a volume controlled mode at an inspired oxygen fraction of 1.0. Lung injury was induced by intravenous injection of 0.1 ml oleic acid per kilogram body weight. Ten sheep were treated with vaporized perfluorohexane for 30 min and followed for 2 h; 10 sheep served as controls. Measurements of blood gases and respiratory and hemodynamic parameters were obtained at regular intervals. RESULTS: Vaporization of perfluorohexane significantly increased arterial oxygen tension 30 min after the end of treatment (P < 0.01). At 2 h after treatment the oxygen tension was 376+/-182 mmHg (mean +/- SD). Peak inspiratory pressures (P < 0.01) and compliance (P < 0.01) were significantly reduced from the end of the treatment interval onward. CONCLUSION: Vaporization is a new application technique for perfluorocarbon that significantly improved oxygenation and pulmonary function in oleic acid-induced lung injury.

Animals↗
PubMed1998

Role of NO and endothelin in hemoglobin-induced pulmonary vasoconstriction.

UNLABELLED: The underlying mechanisms of hemoglobin (Hb)-induced vasoconstriction are not yet well understood. The aim of this study was to elucidate the influence of nitric oxide (NO) and endothelin (ET) on Hb-induced pulmonary vasoconstriction. Therefore, an autologous Hb preparation was administered into isolated rabbit lungs, in which pulmonary artery pressure (PAP) and weight gain was monitored. Either glyceroltrinitrate (GTN; 10(-5) M; n=6), L-arginine (10(-2) M; n=6), L-NAME (10(-4)M; n=6), ET(A)- or ET(B)-receptor antagonists (BQ,23, 10 6M, n=6) or (BQ788, 10(-6) M, n=6) were added to the perfusion fluid and NOx and thromboxane A2 levels were measured. RESULTS: In the control group the Hb-stimulation resulted in a pressure response up to 25.1+/-2.1 mmHg (p < .05), which was 136+/-6% of the reference value. The PAP increase was significantly (p < .05) blunted after GTN (71+/-5%), L-arginine (93+/-6%) and BQ788 (88+/-7%). Pretreatment with L-NAME (139+/-13%) or BQ123 (115+/-9%) did not show significant changes in PAP. CONCLUSION: The reduction of the Hb-induced pulmonary hypertension by NO-donors points toward the inactivation of NO by free hemoglobin. Likewise, ET(B)-receptor mediated vasoconstrictive effects without changes in NOx concentrations seem to play a pathogenetic role in the Hb-induced pulmonary vasoconstriction.

Animals↗
PubMed1998

Blood compatible polymers in intensive care units: state of the art and current aspects of biomaterials research.

The use of artificial organs in cases of acute renal failure, acute respiratory distress syndrome (ARDS) and multiorgan dysfunction syndrome (MODS) has lead to a significant reduction of mortality. However, the interaction between body and biomaterials results in the activation of the coagulation system and in the induction of systemic inflammatory response syndrome. The necessary anticoagulation may be contraindicated and may even further increase the risk for the patient. This article evaluates the currently applied polymeric materials used in intensive care units (ICU) and gives a possible outlook into future developments. It is emphasized that systematic interdisciplinary research of physicians and biomaterial scientists is essential for the successful development of new polymers with improved biocompatibility. For this purpose a brief overview of analytical techniques for surface characterization is given, and future developments to a fully biocompatible polymer are described.

Artificial Organs↗
PubMed1997

Partial carbon dioxide rebreathing: a reliable technique for noninvasive measurement of nonshunted pulmonary capillary blood flow.

OBJECTIVE: To determine the validity and clinical utility of the partial CO2 rebreathing technique for measurement of nonshunted pulmonary capillary blood flow and cardiac output. DESIGN: Prospective, controlled animal laboratory investigation and clinical trial. SETTINGS: Animal research facility and intensive care unit of a university hospital. SUBJECTS: Fifteen adult sheep, weighting 58 to 78 kg. PATIENTS: Mechanically ventilated patients with different underlying diseases (n = 12) and with adult respiratory distress syndrome (ARDS) (n = 8). INTERVENTIONS: CO2 elimination rate (VCO2) was measured breath-by-breath with a system developed for the study and also by gas collection (validation procedure in patients with different underlying diseases). Partial CO2 rebreathing maneuvers, cardiac output by thermodilution, and blood gas analysis were performed in sheep with lung atelectasis and in patients with ARDS. MEASUREMENTS AND MAIN RESULTS: The degree of correlation between VCO2 measured with the system developed and gas collection was very good (r2 = .95, p < .0001), and bias and precision calculations (1 +/- 9 mL/min) showed close agreement between methods. The overall degree of correlation between partial CO2 rebreathing measurements and cardiac output was moderate (r2 = .54, p < .0001), the noninvasive method tending to underestimate cardiac output, as shown by bias and precision calculations (-1.69 +/- 1.90 L/min). In contrast, the overall degree of correlation between partial CO2 rebreathing measurements and nonshunted pulmonary capillary blood flow was good (r2 = .73, p < .0001). Bias and precision calculations (0.25 +/- 0.83 L/min) showed a tendency for the partial CO2 rebreathing technique to slightly overestimate pulmonary capillary blood flow. Variance differences between partial CO2 rebreathing measurements and cardiac output could be mostly explained by intrapulmonary right-to-left shunt fraction (r2 = .51, p < .0001). CONCLUSIONS: Our results support the use of the system developed for breath-by-breath VCO2 measurements. The lack of agreement between partial CO2 rebreathing measurements and cardiac output was mostly explained by intrapulmonary right-to-left shunt, suggesting that this technique may not be appropriate for monitoring cardiac output in patients with increased venous admixture. In contrast, our results demonstrate that the partial CO2 rebreathing technique is reliable for measurement of the effective nonshunted pulmonary capillary blood flow. This technique may prove useful to guide ventilatory therapy adjustments in an attempt to optimize nonshunted pulmonary capillary blood flow.

Adult↗
PubMed1993

[Myxedema coma as a rare postoperative complication].

Myxedema coma is characterized by severe lack of thyroid hormones, unconsciousness and serious restriction of vital functions. The mortality rate still ranges between 50 and 80%. In patients with inapparent hypothyroidism myxedema coma occasionally follows surgery, anesthesia or severe infection. A case of myxedema coma following surgery is reported. CASE REPORT. A 46-year-old woman was anesthesized for hip replacement. The intraoperative cardiovascular situation was characterized by hypotension and tachycardia. On the first postoperative day, unexpectedly a cardiac arrest occurred. Resuscitation with high doses of epinephrine was successful. There was no evidence of myocardial infarction, hypoxia and pulmonary embolism as causative factors for cardiac arrest. A pulmonary artery catheter was inserted and showed low cardiac output. Catecholamines and intravascular fluids were administered without hemodynamic improvement. In the next 5 days pneumonia was followed by ARDS and acute renal failure. After successful treatment of these complications the patient remained in deep coma. An intracerebral disease could be excluded by computerized tomography. Evaluation showed low thyroid hormones (T3; T4) and elevated TSH. The diagnosis of a myxedema coma was assumed. After failure of oral therapy with L-thyroxine (0.025-0.05 mg/day) for 10 days, intravenous therapy with 0.5 mg L-thyroxine was performed. Thirty-six hours later the patient regained consciousness, without cardiac complications. The patient progressed uneventfully under oral therapy with 0.1 mg L-thyroxine and was discharged from the hospital 6 weeks later. DISCUSSION. Pathophysiology and symptomatology of a case of postoperative myxedema coma are described (Tables 1-4). In this patient, the following symptoms occurred: low thyroid hormones (T3; T4), elevated TSH, deep coma, decreased ventilatory response to CO2, diminished myocardial contractility under catecholamine stimulation, impaired renal water excretion. After failure of oral substitution of L-thyroxine, intravenous therapy had to be performed in spite of the high risk of further cardiac complications in this patient. This led to complete recovery with normal neuropsychological and cardiopulmonary parameters. CONCLUSION. Myxedema coma is a rare complication in postoperative care, but in cases of inexplicable unconsciousness thyroid failure should be excluded. If myxedema coma is evident, intravenous therapy with L-thyroxine should be performed under the conditions of extended monitoring.

Coma↗