Dynamic parameters of fluid responsiveness in the operating room : An analysis of intraoperative ventilation framework conditions.

BACKGROUND: Reliable assessment of fluid responsiveness with pulse pressure variation (PPV) depends on certain ventilation-related preconditions; however, some of these requirements are in contrast with recommendations for protective ventilation. OBJECTIVE: The aim of this study was to evaluate the applicability of PPV in patients undergoing non-cardiac surgery by retrospectively analyzing intraoperative ventilation data. MATERIAL AND METHODS: Intraoperative ventilation data from three large medical centers in Germany and Switzerland from January to December 2018 were extracted from electronic patient records and pseudonymized; 10,334 complete data sets were analyzed with respect to the ventilation parameters set as well as demographic and medical data. RESULTS: In 6.3% of the 3398 included anesthesia records, patients were ventilated with mean tidal volumes (mTV) > 8 ml/kg predicted body weight (PBW). These would qualify for PPV-based hemodynamic assessment, but the majority were ventilated with lower mTVs. In patients who underwent abdominal surgery (75.5% of analyzed cases), mTVs > 8 ml/kg PBW were used in 5.5% of cases, which did not differ between laparoscopic (44.9%) and open (55.1%) approaches. Other obstacles to the use of PPV, such as elevated positive end-expiratory pressure (PEEP) or increased respiratory rate, were also identified. Of all the cases 6.0% were ventilated with a mTV of > 8 ml/kg PBW and a PEEP of 5-10 cmH2O and 0.3% were ventilated with a mTV > 8 ml/kg PBW and a PEEP of > 10 cmH2O. CONCLUSION: The data suggest that only few patients meet the currently defined TV (of > 8 ml/kg PBW) for assessment of fluid responsiveness using PPV during surgery.

Lower versus higher hemoglobin threshold for transfusion in ARDS patients with and without ECMO.

BACKGROUND: Efficacy and safety of different hemoglobin thresholds for transfusion of red blood cells (RBCs) in adults with an acute respiratory distress syndrome (ARDS) are unknown. We therefore assessed the effect of two transfusion thresholds on short-term outcome in patients with ARDS. METHODS: Patients who received transfusions of RBCs were identified from a cohort of 1044 ARDS patients. After propensity score matching, patients transfused at a hemoglobin concentration of 8 g/dl or less (lower-threshold) were compared to patients transfused at a hemoglobin concentration of 10 g/dl or less (higher-threshold). The primary endpoint was 28-day mortality. Secondary endpoints included ECMO-free, ventilator-free, sedation-free, and organ dysfunction-free composites. MEASUREMENTS AND MAIN RESULTS: One hundred ninety-two patients were eligible for analysis of the matched cohort. Patients in the lower-threshold group had similar baseline characteristics and hemoglobin levels at ARDS onset but received fewer RBC units and had lower hemoglobin levels compared with the higher-threshold group during the course on the ICU (9.1 [IQR, 8.7-9.7] vs. 10.4 [10-11] g/dl, P < 0.001). There was no difference in 28-day mortality between the lower-threshold group compared with the higher-threshold group (hazard ratio, 0.94 [95%-CI, 0.59-1.48], P = 0.78). Within 28 days, 36.5% (95%-CI, 27.0-46.9) of the patients in the lower-threshold group compared with 39.5% (29.9-50.1) of the patients in the higher-threshold group had died. While there were no differences in ECMO-free, sedation-free, and organ dysfunction-free composites, the chance for successful weaning from mechanical ventilation within 28 days after ARDS onset was lower in the lower-threshold group (subdistribution hazard ratio, 0.36 [95%-CI, 0.15-0.86], P = 0.02). CONCLUSIONS: Transfusion at a hemoglobin concentration of 8 g/dl, as compared with a hemoglobin concentration of 10 g/dl, was not associated with an increase in 28-day mortality in adults with ARDS. However, a transfusion at a hemoglobin concentration of 8 g/dl was associated with a lower chance for successful weaning from the ventilator during the first 28 days after ARDS onset. TRIAL REGISTRATION: ClinicalTrials.gov NCT03871166.

Strategies for diagnosis and treatment of iatrogenic tracheal ruptures.

BACKGROUND: Management of tracheal ruptures in critically ill patients is challenging. Conservative treatment has been described, but in mechanically ventilated patients with distal tracheal ruptures surgical repair might be inevitable. Strategies for diagnosis and treatment of tracheal ruptures and handling of mechanical ventilation remain to be clarified. Our aim was to comprise a structured diagnostic and treatment protocol for patients suspicious of tracheal injury, including detailed principles of mechanical ventilation and specific indications for conservative or surgical treatment. METHODS: Patients with tracheal ruptures were compared in accordance to the need of mechanical ventilation and to indication for surgical repair. In patients suffering from tracheal ruptures affecting the whole tracheal wall and with protrusion of mediastinal structures into the lumen surgery was indicated. We compared ventilatory, hemodynamic and clinical parameters between the different patient groups. We report our structured approach in diagnostics and treatment of tracheal ruptures and place special emphasis on respiratory management. RESULTS: Seventeen patients with tracheal rupture were identified. In 8 patients surgical repair was performed 1.8±1.5 days after diagnosis. Previous to surgery, ventilation parameters improved significantly: plateau pressure decreased, percentage of assisted spontaneous breathing increased and compliance improved. Conservative treatment was successful in long-term ventilated patients (13.7±8 days) even when suffering from distal lesions. CONCLUSION: Invasiveness of mechanical ventilation and obstruction of tracheal lumen might indicate conservative or surgical treatment strategies in long-term ventilated patients suffering from iatrogenic tracheal rupture. Indications for surgical repair remain to be further clarified.

[Danger of fetal acidosis in vaginal delivery from breech presentation (author's transl)]. / Die fetale acidosegefährfung bei vaginaler geburt aus beckenendlage

On the basis of our own experience and the literature the risk of acidosis, which corresponds to the risk of asphyxia, during vaginal delivery of breech presentations is examined. Compared with delivery of vertex presentation it is 3-10 times greater. The risk of acidosis does not depend on the duration of pregnancy and only a little on the parity of the mother. Even with carefully selective indication for primary Caesarean section it cannot be reduced below the high level. Typically there is acute compression of the cord at the end of the first or later stages of labor. Even with intensive intra-partum care it cannot safely be predicted with sufficient certainty. As a criterion of the efficiency of modern obstetrics the impact of acidosis in umbilical blood and its increase in breech presentation is discussed. Only systematic Caesaren section before or early in labor will lower the risk to that of vertex presentation. This is done and recommended by the authors. Links between acdosis in umbilical blood and permanent cerebral damage are probable but by no means certain and their importance in unknown. Selective indication for Caesarean section which has to be made generously, represents an acceptable alternative.