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Biomedical subjects

Spyros G Zakynthinos

Publications and source records attributed to Spyros G Zakynthinos.

5 recordsLinked to original sources
PubMed2005

Static pressure volume curves and body posture in acute respiratory failure.

OBJECTIVE: In acute respiratory distress syndrome the body posture effects on pressure-volume (PV) curves are still unclear. We examined the effects of prone position on inflation PV curves and their potential relationships with postural alterations in gas exchange. DESIGN AND SETTING: Prospective study with patients serving as their own controls in a university-affiliated 30-bed intensive care unit. PATIENTS AND PARTICIPANTS: Thirteen anesthetized, paralyzed, semirecumbent, mechanically ventilated patients with early/severe/diffuse ARDS. INTERVENTIONS: Sequential body posture changes: preprone semirecumbent, prone, and postprone semirecumbent. MEASUREMENTS AND RESULTS: In each posture hemodynamics, gas exchange, and lung volumes were determined before/during removal and after restoration of positive end-expiratory pressure (PEEP=10.2+/-0.6 cmH2O). At zero PEEP PV curves of respiratory system, lung, and chest wall were constructed. Prone position vs. preprone semirecumbent resulted in significantly reduced pressure at lower inflection point of lung PV curve (2.2+/-0.2 vs. 3.7+/-0.5 cmH2O) and increased volume at upper inflection point (0.87+/-0.03 vs. 0.69+/-0.05 l). Postural reduction in lower inflection point pressure of lung PV curve was the sole independent predictor of pronation-induced increases in PaO2/FIO2 (R2=0.76). PaO2/FIO2 increases were also significantly related with increases in functional residual capacity (R2=0.60). CONCLUSIONS: In early/severe/diffuse ARDS prone position reduces lower inflection point pressure and increases upper inflection point UIP volume of the lung PV curve. Lower inflection point pressure reductions explain oxygenation improvements, which are also associated with a postural increase in functional residual capacity.

Adult↗
PubMed2005

An evaluation of McCoy balloon laryngoscopy in patients with moderate-to-major endotracheal intubation difficulty.

UNLABELLED: We hypothesized that combined McCoy-balloon laryngoscopy may facilitate airway management relative to McCoy or balloon laryngoscopy. In 10 anesthetized/paralyzed patients with prior intubation difficulty scale scores of >5, McCoy-balloon laryngoscopy versus conventional/balloon/McCoy laryngoscopies resulted in greater laryngeal aperture exposure (2.3 +/- 0.6 versus 0.6 +/- 0.2/1.4 +/- 0.4/1.5 +/- 0.6 cm2, respectively), lower intubation difficulty scale score (0.00 (0.00-0.00) versus 6.00 (6.00-8.25)/1.50(0.00-4.00)/2.00(0.75-5.00), respectively, median [interquartile range]), and 9%-74% shorter time to intubation confirmation (P < 0.05-0.001 for all). Balloon and McCoy laryngoscopies improved laryngoscopic/intubating conditions relative to conventional laryngoscopy. In patients with moderate-to-major conventional airway management difficulty, McCoy-balloon laryngoscopy further improves laryngoscopic/intubating conditions. IMPLICATIONS: This study shows that, in patients with moderate-to-major conventional airway management difficulty, combined McCoy-balloon laryngoscopy results in improved laryngoscopic/intubating conditions when compared with the conventional, McCoy, and balloon laryngoscopic techniques. McCoy-balloon laryngoscopy combines the merits of McCoy and balloon laryngoscopy and can be recommended for patients with moderate-to-major intubation difficulty.

Adult↗
PubMed2004

Sepsis severity is the major determinant of circulating thrombopoietin levels in septic patients.

OBJECTIVE: To measure serum thrombopoietin levels and to investigate their relationship with platelet counts and other potential determinants in septic patients. DESIGN: Prospective study comparing septic patients and healthy volunteers. SETTING: General intensive care units in two tertiary university hospitals. PATIENTS: A total of 152 consecutive septic patients (69 with sepsis, 24 with severe sepsis, and 59 with septic shock). Twenty-two healthy volunteers served as control subjects. Sepsis severity was determined by grading septic patients in those having sepsis, severe sepsis, and septic shock. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: After blood sampling, platelet counts, and serum thrombopoietin, interleukin-6 and C-reactive protein levels were measured. Platelets did not decrease in patients with sepsis, but they significantly decreased in patients with severe sepsis and septic shock (p <.01 vs. controls and sepsis). In contrast, thrombopoietin levels (median [range]) increased in patients with sepsis (159 [34-1272] pg/mL) compared with controls (57 [33-333] pg/mL, p <.001), exhibiting further significant increase in patients with severe sepsis and septic shock (461 [73-1550] and 522 [45-2313] pg/mL, respectively, p <.001 vs. sepsis). In multiple regression analysis, thrombopoietin levels were independently related only to sepsis severity (higher in patients with increased sepsis severity, p <.001) and platelet counts (higher in patients with lower platelet counts, p =.004). Sepsis severity accounted for most of the variance explained by the model. Thrombopoietin was significantly related to interleukin-6 (r =.26) and C-reactive protein (r =.37, p <.001 for both). In serial measurements, interleukin-6 peak values constantly preceded those of thrombopoietin, whereas peaks in thrombopoietin levels coincided with clinical episodes of septic shock. CONCLUSIONS: Sepsis severity is the major determinant of elevated thrombopoietin levels in septic patients, whereas platelet count is a secondary determinant. Thrombopoietin represents a potential marker of sepsis severity.

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PubMed2003

Prone position improves lung mechanical behavior and enhances gas exchange efficiency in mechanically ventilated chronic obstructive pulmonary disease patients.

UNLABELLED: Pronation might favorably affect respiratory system (rs) mechanics and function in volume-controlled, mode-ventilated chronic obstructive pulmonary disease (COPD) patients. We studied 10 COPD patients, initially positioned supine (baseline supine [supine(BAS)]) and then randomly and consecutively changed to protocol supine (supine(PROT)), semirecumbent, and prone positions. Rs mechanics and inspiratory work (W(I)) were assessed at baseline (0.6 L) (all postures) and sigh (1.2 L) (supine(BAS) excluded) tidal volume (V(T)) with rapid airway occlusion during constant-flow inflation. Hemodynamics and gas exchange were assessed in all postures. There were no complications. Prone positioning resulted in (a) increased dynamic-static chest wall (cw) elastance (at both V(Ts)) and improved oxygenation versus supine(BAS), supine(PROT), and semirecumbent, (b) decreased additional lung (L) resistance-elastance versus supine(PROT) and semirecumbent at sigh V(T), (c) decreased L-static elastance (at both V(Ts)) and improved CO(2) elimination versus supine(BAS) and supine(PROT), and (d) improved oxygenation versus all other postures. Semirecumbent positioning increased mainly additional cw-resistance versus supine(BAS) and supine(PROT) at baseline. V(T) W(I)-sub-component changes were consistent with changes in rs, cw, and L mechanical properties. Total rs-W(I) and hemodynamics were unaffected by posture change. After pronation, five patients were repositioned supine (supine(POSTPRO)). In supine(POSTPRO), static rs-L elastance were lower, and oxygenation was still improved versus supine(BAS). Pronation of mechanically ventilated COPD patients exhibits applicability and effectiveness and improves oxygenation and sigh-L mechanics versus semirecumbent ("gold standard") positioning. IMPLICATIONS: By assessing respiratory mechanics, inspiratory work, hemodynamics, and gas exchange, we showed that prone positioning of mechanically ventilated chronic obstructed pulmonary disease patients improves oxygenation and lung mechanics during sigh versus semirecumbent positioning. Furthermore, certain pronation-related benefits versus preprone-supine positioning (reduced lung elastance and improved oxygenation) are maintained in the postprone supine position.

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