Minute ventilation stabilization during all pressure-control / support mechanical ventilation modes.

The main goal of our prospective randomized study was comparing compare the effectiveness of ventilation control method "Automatic proportional minute ventilation (APMV) "versus manually set pressure control ventilation modes in relationship to lung mechanics and gas exchange. 80 patients undergoing coronary artery bypass grafting (CABG) were randomized into 2 groups. 40 patients in the first group No.1 (APMV group) were ventilated with pressure control (PCV) or pressure support ventilation (PSV) mode with APMV control. The other 40 patients (control group No.2) were ventilated with synchronized intermittent mandatory ventilation (SIMV-p) or pressure control modes (PCV) without APMV. Ventilation control with APMV was able to maintain minute ventilation more precisely in comparison with manual control (p<0.01), similarly deviations of ETCO(2) were significantly lower (p<0.01). The number of manual corrections of ventilation settings was significantly lower when APMV was used (p<0.01). The differences in lung mechanics and hemodynamics were not statistically significant. Ventilation using APMV is more precise in maintaining minute ventilation and gas exchange compared with manual settings. It required less staff intervention, while respiratory system mechanics and hemodynamics are comparable. APMV showed as effective and safe method applicable on top of all pressure control ventilation modes.

Relationship between dynamic expiratory time constant tau(edyn) and parameters of breathing cycle in pressure support ventilation mode.

Study of the relationship between ventilation parameters: monitored expiratory time constant - tau(edyn) and breathing - trigger frequency (f(trig)) and time of breathing cycle (T(cy)) are main goals of this article. Parameters were analyzed during last 4+/-2 h before weaning from ventilation in 66 patients ventilated in pressure support mode (PSV). We have found out, that there exist mathematical relationships, observed during adequate gas exchange, yet not described. Monitored parameters are represented by tau(edyn), f(trig) and T(cy). The analysis showed close negative correlation between T(cy) and f(trig) (R(2)=0.903). This implies that each increasing of tau(edyn) causes decreasing of f(trig) and vice versa. The calculation of regression equation between tau(edyn) and T(cy) outlined that T(cy) = 5.2625 * tau(edyn) + 0.1242 (R(2)=0.85). Regulation of respiratory cycles by the respiratory center in the brain is probably based on evaluation of tau(edyn) as the tau(edyn) probably represents a regulatory element and T(cy) regulated element. It can be assumed, that respiratory center can optimize the work of breathing in order to minimize energy in system patient + ventilator. The unique relationship, described above could be useful in clinical practice for development of new ventilation modes.

[Diagnosis and immediate results of treatment of patients with non-epithelial tumors of upper gastrointestinal tract].

We presented an experience of treatment of 225 patients with non-epithelial tumors of upper gastrointestinal tract. Complicated disease's course was observed in 24% of cases. Tactical approaches are discussed depending on localization, dimensions and nature of tumor growth. Also indications for minimally invasive operations are defined. It was operated 102 (45.3%) of above-mentioned patients. Conventional surgical interventions were performed in 49 (48.0%) cases, laparoscopic operations - in 11 (10.8%) observations, endoscopic techniques using flexible endoscope - in 42 (41.2%) patients. One hundred and twenty-three (54.7%) patients were under dynamic observation. Technical features of the performed operations are described in the article. Complications were diagnosed in 8 patients including intraoperative in 3 cases and postoperative in 5 cases. Postoperative mortality was 2.0% (2 of 102 died). Overall mortality was 1.3% (3 of 225 patients died). Gastrointestinal stromal tumor (38) and leiomyoma (29) were the most frequent findings among removed tumors.

Normalization of blood lactate as early end-point of polytrauma treatment.

BACKGROUND: The main aim of the early treatment of polytrauma is recovery of patient's physiological functions. The early achievement of therapeutic goals, mainly adequate tissue perfusion and repayment of oxygen debt, are postulated. The aim of the study was to confirm whether blood lactate level as a quantifier of oxygen deficit, as well as normalization of blood lactate level within the first 24 hours, have an impact on the mortality and morbidity of seriously injured patients. METHODS: Sixty-nine mechanically ventilated patients with a severe trauma and organ dysfunction defined according to SOFA score and ISS >17, age >15 years, were enrolled into this retrospective study. 8 patients died within first 24 hours, 8 patients did not reach serum lactate level above 2 mmol/l on admission to hospital. The hypothesis that normalization of serum lactate level within 24 hours is related to lower mortality and morbidity, was assessed. Reduced mortality and morbidity were represented by lower severity of multi-organ dysfunction, the highest SOFA score during hospitalization, lower incidence of sepsis, number of days in ICU and artificial ventilation. RESULTS: The association between severity of multi-organ failure (p=0.0006), mortality (p=0.0022) and repayment of oxygen debt was confirmed. Hypothesis of sepsis incidence was not confirmed (p=0.34). The association between number of days on artificial ventilation and number of days in ICU to repayment of oxygen debt was not confirmed either. Multivariate significant factors were age, GCS, ISS and SOFA score on patient's admission. CONCLUSION: The patients, who repaid oxygen debt within first 24 hours, have lower morbidity and mortality (Tab. 6, Ref. 19).