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Biomedical subjects

A Armaganidis

Publications and source records attributed to A Armaganidis.

At least 19 recordsLinked to original sources
PubMed2006

Transorbital sonographic monitoring of optic nerve diameter in patients with severe brain injury.

OBJECTIVE: We investigated whether alterations in the optic nerve diameter (OND) correlated with brain computed tomography (CT) imaging results among patients with brain injury and whether monitoring of OND could predict brain death. PATIENTS AND METHODS: We enrolled 54 patients with brain injury (Glasgow Coma Scale < 8) and 53 controls. OND measurements were performed 3 mm posterior to the papillae by means of transorbital sonography. The severity of the injury was classified according to a semiquantitative CT neuroimaging scale (1 to 4). All patients underwent 3 repeated evaluations of OND combined with synchronous CT scans. RESULTS: Twenty-two patients progressed to brain death, while 32 patients showed gradual clinical improvement. Upon admission, the patients showed significantly increased OND (4.84 +/- 1.2 mm) compared with the controls (3.49 +/- 1.1 mm; P < .001). The median intraobserver variation of OND was 0.2 mm (95% confidence intervals [CI]: 0.1-0.7). The median interobserver variation of OND was 0.3 mm (95% CI: 0.1-0.9). Alterations in the OND were significantly correlated with the neuroimaging scale on 3 repeated evaluations: r = .65, r = .70, and r = .73 (all P < .001). An OND greater than 5.9 mm (specificity = 65% and sensitivity = 74%; P < .01) and a 2.5 mm increased OND between repeated measurements (specificity = 70% and sensitivity = 81%; P < .01) were associated with a poor prognosis. CONCLUSIONS: Alterations in OND strongly correlated with neuroimaging results among patients with brain injury. However, monitoring of OND exhibited a low predictive value for brain death.

APACHE↗
PubMed2005

Does soluble triggering receptor expressed on myeloid cells-1 play any role in the pathogenesis of septic shock?

In order to define the significance of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) upon progression from sepsis or severe sepsis to septic shock a prospective study was designed with 90 enrolled patients with septic syndrome due to ventilator-associated pneumonia. Blood was sampled on seven consecutive days upon initiation of symptoms and concentrations of tumour necrosis factor-alpha (TNFalpha), interleukin-6 (IL-6), IL-8 and sTREM-1 were estimated in serum by an enzymeimmunoassay. No differences in concentrations of TNFalpha, IL-6 and IL-8 were found between patients with sepsis, severe sepsis and septic shock on the first day of presentation of symptoms. Patients presenting with septic shock had concentrations of sTREM-1 significantly higher than both patients with sepsis and severe sepsis on the first day; no difference was found between patients with sepsis and severe sepsis. A positive correlation was detected between sTREM-1 and the white blood cell count. Serum levels of sTREM-1 were significantly lower in patients where VAP resolved compared to those where VAP did not resolve; similar findings were noted between patients who eventually survived and those who died. IL-6 followed the kinetics of sTREM-1 in correlation to patients's prognosis; levels of TNFalpha and IL-8 were unrelated to prognosis. It is concluded that sTREM-1 is particularly increased upon evolution from sepsis or severe sepsis to septic shock. Its sustained increase is an indication of poor outcome. The underlined pathophysiological role of sTREM-1 for the transition from sepsis or severe sepsis to septic shock might constitute a novel target for immunomodulatory therapy.

Aged↗
PubMed2000

Pulmonary capillary endothelium-bound angiotensin-converting enzyme activity in acute lung injury.

BACKGROUND: Pulmonary capillary endothelium-bound (PCEB) angiotensin-converting ectoenzyme (ACE) activity alteration is an early, sensitive, and quantifiable lung injury index in animal models. We hypothesized that (1) PCEB-ACE alterations can be found in patients with acute lung injury (ALI) and (2) PCEB-ACE activity correlates with the severity of lung injury and may be used as a quantifiable marker of the underlying pulmonary capillary endothelial dysfunction. METHODS AND RESULTS: Applying indicator-dilution techniques, we measured single-pass transpulmonary hydrolysis of the synthetic ACE substrate (3)H-benzoyl-Phe-Ala-Pro (BPAP) in 33 mechanically ventilated, critically ill patients with a lung injury score (LIS) ranging from 0 (no lung injury) to 3.7 (severe lung injury) and calculated the kinetic parameter A(max)/K(m). Both parameters decreased early during the ALI continuum and were inversely related to APACHE II score and LIS. Hydrolysis decreased with increasing cardiac output (CO), whereas 2 different patterns were observed between CO and A(max)/K(m). CONCLUSIONS: PCEB-ACE activity decreases early during ALI, correlates with the clinical severity of both the lung injury and the underlying disease, and may be used as a quantifiable marker of underlying pulmonary capillary endothelial dysfunction.

Adolescent↗
PubMed2000

Enterococcal infections in a Greek intensive care unit: a 5-y study.

In this study we determined the incidence, resistance pattern, and mortality rate associated with infection caused by Enterococcus faecalis and Enterococcus faecium among patients in a multidisciplinary intensive care unit (ICU). A total of 111 patients with E. faecalis and 60 with E. faecium infections were identified during a 5-y period (1992-96). We observed an increase in the incidence of enterococcal infections (from 5.46 to 8.46 per 1000 patients-days, p = 0.0112), due mainly to the increased incidence of E. faecium (from 0.45 to 4.06 per 1000 patients-days, p = 0.002). Blood was the most common site of enterococcus isolation. E. faecium was more resistant to antibiotics than E. faecalis, but no vancomycin resistant enterococcus was isolated. Patients with E. faecium infection had a significantly higher mortality than patients with E. faecalis infection (66% vs. 41.5%, p = 0.0035 for infection from any site and 85.7 vs. 47.7%, p = 0.012 for bacteremic patients). r 4n- D I .- .- - .. . .

Adolescent↗
PubMed2000

Intrinsic positive end-expiratory pressure in mechanically ventilated patients with and without tidal expiratory flow limitation.

OBJECTIVE: To assess static intrinsic positive end-expiratory pressure (PEEPi,st) and expiratory flow limitation (FL) in 32 consecutive mechanically ventilated patients with acute respiratory failure (ARF), using a commercial ventilator with an incorporated device that allows the application of a negative expiratory pressure (NEP). DESIGN: Prospective clinical study. SETTING: Multidisciplinary intensive care unit of a university hospital. PATIENTS: Thirty-two consecutive ventilated patients with ARF of various etiologies. INTERVENTIONS: Evaluation of respiratory mechanics, PEEPi,st, and FL from pressure, flow, and volume traces provided by the ventilator. MEASUREMENTS: Peak airway pressure, PEEPi,st, dynamic elastance, and interrupter resistance were measured in relaxed patients in a supine position. Comparison of tidal flow-volume curves before and during the application of an NEP of 5 cm H2O was used to assess tidal expiratory FL. RESULTS: Twelve of 32 patients studied exhibited tidal expiratory FL, which was detected by the absence of increase in expiratory flow despite application of an NEP over the entire or part of the baseline expiratory flow-volume curve. All patients exhibited PEEPi,st, which amounted to 1.2 +/- 0.9 cm H2O (mean +/- SD) in the 20 non-FL patients and 7.1 +/- 2.8 cm H2O in the 12 FL patients (p < 0.00001). The majority of patients with ARF resulting from underlying lung disease (11 of 13) had FL and a PEEPi,st > 4 cm H2O, whereas in patients with ARF of extrapulmonary origin, PEEPi,st was always < 4 cm H2O and only one grossly obese patient exhibited FL. Based on multiple regression analysis, in non-FL patients, PEEPi,st correlated significantly only with minute ventilation, whereas in FL patients PEEPi,st correlated significantly with peak airway pressure. CONCLUSIONS: Because all the patients exhibited PEEPi,st and 12 of 32 patients (38%) also had FL, the authors conclude that the assessment of these variables at the bedside could provide useful information concerning respiratory mechanics in mechanically ventilated patients.

Adolescent↗
PubMed2000

Expiratory flow limitation and intrinsic positive end-expiratory pressure at zero positive end-expiratory pressure in patients with adult respiratory distress syndrome.

It has been suggested that in patients with adult respiratory distress syndrome (ARDS), intrinsic positive end-expiratory pressure (PEEPi) is generated by a disproportionate increase in expiratory flow resistance. Using the negative expiratory pressure (NEP) technique, we assessed whether expiratory flow limitation (EFL) and PEEPi were present at zero PEEP in 10 semirecumbent, mechanically ventilated ARDS patients. Because bronchodilators may decrease airway resistance, we also investigated the effect of nebulized salbutamol on EFL, PEEPi, and respiratory mechanics in these patients, and in seven patients we measured the latter variables in the supine position as well. In the semirecumbent position, eight of the 10 ARDS patients exhibited tidal EFL, ranging from 5 to 37% of the control tidal volume (VT), whereas PEEPi was present in all 10 subjects, ranging from 0.4 cm H(2)O to 7.7 cm H(2)O. The onset of EFL was heralded by a distinct inflection point on the expiratory flow-volume curve, which probably reflected small-airway closure. Administration of salbutamol had no statistically significant effect on PEEPi, EFL (as %VT), or respiratory mechanics. EFL (%VT) and PEEPi were significantly higher in the supine position than in the semirecumbent position, whereas the other respiratory variables did not change. Our results suggest that in the absence of externally applied PEEP, most ARDS patients exhibit EFL associated with small-airway closure and a concomitant PEEPi.

Adult↗
PubMed1997

Changes in thoracopulmonary compliance and hemodynamic effects of positive end-expiratory pressure in patients with or without heart failure.

PURPOSE: The purpose of this study was to confirm that positive end-expiratory pressure (PEEP) has a different effect on cardiac index (CI) in patients with or without heart failure, even after controlling for differences in thoracopulmonary compliance (Ctp) and minimizing the secondary effects of PEEP related changes in oxygenation and breathing effort. MATERIALS AND METHODS: The hemodynamic effects of PEEP were evaluated in two groups of sedated and paralyzed patients with a low Ctp at 0 PEEP: 12 patients with normal pulmonary artery occlusion pressure (Ppao) and a CI > 2.5 L/min and 12 patients with a CI < 2.5 L/min and increased oxygen extraction ratio, despite a Ppao > 15 mm Hg. RESULTS: In patients with low CI and high Ppao, PEEP had no hemodynamic effect and Ctp remained low at all PEEP levels. However, PEEP-induced CI reduction in patients with normal cardiovascular function was associated with an increase in Ctp with incremental PEEP. Concerning PEEP-related hemodynamic effects, the significance between group differences persisted when data were analyzed after controlling for Ctp changes. However, Ctp changes with PEEP were the most significant correlators and discriminators of the magnitude and direction of PEEP-induced CI change. CONCLUSIONS: We conclude that (1) the observed different effect of PEEP on CI in patients with and without heart failure persists after the elimination of secondary effects due to underlying differences in Ctp, oxygenation, and breathing effort; and (2) PEEP-related changes in Ctp should be taken into consideration when dealing with the cardiovascular effects of PEEP. Our data support the hypothesis that, in addition to the transmission of PEEP to the pleural space, changes in lung volume are a significant determinant of PEEP-induced CI changes.

Adult↗
PubMed1997

Functional and control integration of an ICU, LIS and PACS information system.

The need for collaboration and data sharing among systems dedicated to individual functional areas and user groups has initiated major efforts towards the development of an integrated hospital information system. Major issues in the development of any integrated architecture that incorporates autonomous departmental systems include the development of commonly accepted interaction mechanisms, standardisation, the structure of the computerised patient record, its extensibility, as well as limitations multimedia data impose. This paper presents work done within project IHIS, a nationally funded project for the development of an integrated hospital information system that provides ICU staff with access to both the ICU assisting laboratory information system's data as well as radiological multimedia data.

Clinical Laboratory Information Systems↗
PubMed1995

Should mechanical ventilation be optimized to blood gases, lung mechanics, or thoracic CT scan?

This study was aimed at providing data for optimization of mechanical ventilation in patients with acute respiratory distress syndrome (ARDS). The effects of ventilation with positive end-expiratory pressure (PEEP) titrated to blood gases were studied by thoracic computed tomographic (CT) scans and lung mechanics measurements in eight patients. CT density histograms at end-expiration were used to investigate the effects of PEEP on three differently aerated zones. Static pressure-volume (P-V) curves were used to determine the deflection point above which baro-volotrauma (a combination of barotrauma and volotrauma) may occur. Peak pressures, plateau pressures, and lung volumes measured by Respitrace were compared with the deflection point. CT scan showed that PEEP increased "normally aerated" areas, decreased "nonaerated" areas, and did not change "poorly aerated" zones. No correlations were found between CT scan and either PaO2 or mechanical data. Pressure at the deflection point was lower than the usually recommended 35 to 40 cm H2O for peak pressure in four patients (range, 28 to 32 cm H2O). With regard to plateau pressures, only one patient was ventilated above the deflection point. However, monitoring of volumes showed that these four patients had an end-inspiratory volume above this point. We conclude that mechanical ventilation may be initially adjusted on the basis of blood gas values and then optimized on the basis of lung mechanics to limit the risk of baro-volotrauma.

Adolescent↗
PubMed1994

Accuracy assessment for three fiberoptic pulmonary artery catheters for SvO2 monitoring.

OBJECTIVE: To compare values of SvO2 obtained by reflectance spectrophotometry continuous monitoring with those obtained from blood samples measurements by transmission spectrophotometry (Co-Oximetry). DESIGN: Values of SvO2 recorded by three pulmonary artery catheters for continuous monitoring, SAT1, SAT2 and Oximetrix3 (OX3), were compared in a prospective manner to those measured on blood samples by a Co-Oximeter, using the statistical analysis of Bland and Altman. SETTING: Adult intensive care unit in an University Hospital. PATIENTS: 37 patients admitted for acute respiratory failure and/or shock who required hemodynamic monitoring. MAIN RESULTS: The bias (average under- or overestimation) was small for all comparative measurements: +1.3, -0.2 and +1.0 sat% for SAT1, SAT2 and OX3, respectively. However, limits of agreement were only acceptable for SAT2 (-8.3 to +7.9 sat%) and OX3 (-6.7 to +8.6 sat%), but not for SAT1 (-23.3 to +25.9 sat%). No significant drift during 24 h was found with the three catheters. However, in vitro calibration was only found acceptable for SAT2 and OX3. The results were not influenced by the numbers of wavelengths of the device (2 for SAT1 and SAT2, and 3 for OX3) nor did they correlate with any of the hemodynamic and biochemical variables tested. CONCLUSION: For usual monitoring in the ICU, SAT2 and OX3, gave SvO2 values which are in acceptable agreement with SvO2 measured on blood samples by Co-Oximetry.

Aged↗
PubMed1992

Passive partitioning of respiratory volumes and time constants in ventilated patients.

If the thoracoabdominal partitioning of volumes in the mechanical respiratory apparatus was constant, one transducer of indirect spirometry should be sufficient to measure volume variations. To verify this hypothesis we used respiratory inductive plethysmography (RIP) in 16 paralysed patients, of whom eight had normal lungs and 8 had not, to measure: 1) the thoracoabdominal partitioning of volumes (400-1,200 ml) insufflated from either a syringe (Syr) or a ventilator (Vent); and 2) thoracic (Tho) and abdominal (Abd) time constants (T0.368) on spontaneous deflation to barometric pressure. In eleven additional subjects with normal lungs we measured only the time constants. 1) Correlation coefficients of the calibration lines were in all but one subject > 0.98. In all patients the error of volume was < +/- 10% when either one of two coils alone was used to assess volumes with no difference between the two coils; 2) Partitioning varied little with volumes (4 +/- 2%), but widely between subjects, with no group average significant difference between Syr and Vent; 3) T0.368 were identical for Tho and Abd except in one patient; 4) Partitioning and T0.368 were volume size independent. We conclude that, to measure volume variations and time constants in ventilated, paralysed patients, the use of either a thoracic or abdominal single coil RIP is justified. We also provide the normal range for time constant in 19 subjects (0.73 +/- 0.29 s).

Adult↗
PubMed1991

A single-compartment model cannot describe passive expiration in intubated, paralysed humans.

The time-course of thoracic volume changes (respiratory inductive plethysmograph) during relaxed expiration was studied in 11 intubated, paralysed, mechanically ventilated subjects. The semilog volume-time curves show that expiration is governed by two apparently separate mechanisms: one causes emptying of most of the expired volume (approximately 80%) with a time constant of 0.50 +/- 0.22 s for a baseline tidal volume of 0.44 +/- 0.12 l (mean +/- SD) and 0.37 +/- 0.14 s when the tidal volume is reduced (VTP); the other contributes a relatively small amount to the expired volume over a significantly longer time, the time constant amounting to 3.27 +/- 1.54 s for baseline VT and 2.95 +/- 1.65 s for VTp. The first mechanism probably reflects the standard elastic and flow resistive properties of the respiratory system, while the second, slower compartment, is probably an expression of the viscoelastic properties of the pulmonary and chest wall tissues.

Adult↗
PubMed1990

Is intensive care justified for patients with haematological malignancies?

The course of 260 adults with haematological malignancies admitted to a medical intensive care unit was studied to evaluate the value of life support techniques and to research predictive factors. The overall in the medical intensive care unit (MICU) and hospital mortality rates were respectively 43% (113 patients) and 57% (148 patients). Among survivors, 64% (49 patients) were still alive after 6 months and 44% (35 patients) after 1 year. Among 34 haemodialysed patients, the MICU mortality was 67% (23 patients) and among 111 mechanically ventilated patients 85% (94 patients). Prolonged mechanical ventilation, more than seven days, was performed in 11 of the 17 survivors and did not influence long term survival. No individual predictor of mortality was found comparing survivors and non-survivors. However, SAPS, intractable sepsis and failure of more than one organ system were significantly different in non-survivors (p less than 0.001). Among the 20 patients requiring both mechanical ventilation and haemodialysis, only two left the MICU and both died soon thereafter. We conclude that life support therapy should be initiated in patients with haematological disorders and that prolonged mechanical ventilation is compatible with long term survival. However, the combination of mechanical ventilation and haemodialysis is always associated with a poor prognosis and therefore the use of both techniques simultaneously for one patient is questionable.

Adult↗
PubMed1990

Mechanical effects of PEEP in patients with adult respiratory distress syndrome.

In 10 patients with adult respiratory distress syndrome, we studied the effects on respiratory system mechanics of two levels of positive end-expiratory pressure (PEEP), best PEEP (BP) and half of this value (HBP), using a respiratory inductive plethysmograph (RIP) combined with a super syringe. We found the following. 1) Inflation compliance of pressure-volume (PV) curves did not change significantly. 2) End-expiratory volume increased with HBP and further with BP (278 +/- 186 and 464 +/- 313 ml, respectively, P less than 0.01). This increase was positively correlated with inflation compliance for HBP and BP (r = 0.794, P less than 0.01 and r = 0.876, P less than 0.01, respectively). 3) No dynamic hyper-inflation was detected on mechanical ventilation at zero end-expiratory pressure (ZEEP), and the time constant of the respiratory system was in the normal range (0.79 +/- 0.21 s). 4) Hysteresis of PVrip curves, which were corrected for gas exchange, decreased significantly with PEEP (P less than 0.05). We conclude that PEEP does not change inflation PV curve but induces an increase in intrathoracic volume whose magnitude is related to compliance and PEEP level. The reduction of hysteresis with PEEP suggests less gas trapping and thus a functional improvement.

Adolescent↗
PubMed1989

[Relation of oxygen transport and consumption. Role of impaired tissue uptake].

In healthy subjects, when oxygen transport is gradually decreased, oxygen consumption is maintained as tissue oxygen extraction is increased. When delivery is decreased further, there is a critical level below which tissue extraction cannot increase in proportion to the reduced delivery, and oxygen consumption falls. Blood lactate levels then rise, a sign of tissue hypoxia, despite further increases in oxygen extraction as delivery drops below this critical level. There are two major mechanisms which tend to prevent tissue hypoxia in case of reduced oxygen delivery: regional redistribution of blood flow and an increase in the number of perfused capillaries. This possibility of regulating blood flow distribution may be lost during disseminated intravascular coagulation, alpha-adrenergic receptor blockade, hypothermia, arteriovenous shunting. All these alterations have been reported as occurring in sepsis. An abnormal dependency on oxygen supply is observed during bacteriaemia or endotoxinaemia. This is secondary to a reduced ability, at the whole body level, to extract oxygen from a limited supply. The inability to increase oxygen extraction is related to a maldistribution of the cardiac output, with "stealing" of blood, i.e. overperfusion of some organs (skeletal muscle) rather than those where perfusion is rapidly compromised (small intestine). Endotoxin also reduces the efficacy of oxygen extraction within the isolated intestinal segment, whereas that within other organs is preserved. These observations are similar to findings in patients with sepsis who seem to have both an increased demand in oxygen, and a reduced ability to extract it at the tissue level.

Biological Transport↗
PubMed1989

[Weaning from artificial respiration: value of continuous monitoring of mixed venous oxygen saturation].

Weaning from mechanical ventilation is particularly difficult in patients with combined cardiac and respiratory failure. Continuous monitoring of mixed venous blood oxygen saturation (SvO2) redefines weaning in terms of tissue oxygenation. A stable SvO2 greater than 60% during weaning is a reliable index of weanability. However, further studies are required to establish a tolerance threshold for SvO2 during weaning. In the limited experience reported here, an immediate and abrupt fall in SvO2, when the patient started to breathe spontaneously was invariably associated with difficulties in weaning. In some patients, other signs of left ventricular dysfunction rapidly ensued, with a fall in cardiac index. Weaning remained possible if the treatment was capable of increasing cardiac output and normalizing SvO2. If, during spontaneous breathing, SvO2 remained stable in the 50-55% range, with no significant decrease in cardiac output, abrupt and unpredictable drops of SvO2 under 40% range occurred. Such falls always preceded signs of tissue hypoxia, leading to a resumption of controlled mechanical ventilation. However, further studies are required to fully delineate the role of SvO2 in the fine tuning of inotropic support and ventilatory assistance in the difficult weaning of patients recovering from cardio-respiratory failure.

Cardiac Output↗