Leakage Characteristics of Dual-Cannula Fenestrated Tracheostomy Tubes during Positive Pressure Ventilation: A Bench Study.

This study compared the leakage characteristics of different types of dual-cannula fenestrated tracheostomy tubes during positive pressure ventilation. Fenestrated Portex® Blue Line Ultra®, TRACOE® twist, or Rüsch® Traceofix® tracheostomy tubes equipped with nonfenestrated inner cannulas were tested in a tracheostomy-lung simulator. Transfenestration pressures and transfenestration leakage rates were measured during positive pressure ventilation. The impact of different ventilation modes, airway pressures, temperatures, and simulated static lung compliance settings on leakage characteristics was assessed. We observed substantial differences in transfenestration pressures and transfenestration leakage rates. The leakage rates of the best performing tubes were <3.5% of the delivered minute volume. At body temperature, the leakage rates of these tracheostomy tubes were <1%. The tracheal tube design was the main factor that determined the leakage characteristics. Careful tracheostomy tube selection permits the use of fenestrated tracheostomy tubes in patients receiving positive pressure ventilation immediately after stoma formation and minimises the risk of complications caused by transfenestration gas leakage, for example, subcutaneous emphysema.

Sonographic patterns of lung consolidation in mechanically ventilated patients with and without ventilator-associated pneumonia: a prospective cohort study.

PURPOSE: Thoracic ultrasound (TUS) has been successfully used in the diagnosis of community-acquired pneumonia. Little is known about its diagnostic potential in ventilator-associated pneumonia (VAP). The purpose of this study was to systematically describe the morphology and temporal changes of sonographic patterns in mechanically ventilated patients and to evaluate the diagnostic performance characteristics of TUS-based VAP diagnoses. MATERIALS AND METHODS: Patients who were placed on invasive ventilation for reasons other than pneumonia and who were considered at risk for the development of VAP received daily TUS examinations while being closely monitored for the development of pneumonia. RESULTS: Fifty-seven patients were studied. The incidence of VAP was 21.1%. Sonographic patterns of reduced or absent lung aeration were found in 64.2% of examinations. The sonographic pattern of lung consolidation with either dynamic or static air bronchograms was 100% sensitive and 60% specific for VAP in those patients who developed clinical signs and symptoms compatible with pneumonia. The pretest and posttest probabilities were 0.38 and 0.6, respectively. CONCLUSIONS: Sonographic patterns of abnormal aeration are frequently observed in mechanically ventilated patients. If sonographic lung consolidation with either static or dynamic air bronchograms is absent, VAP is highly unlikely. The presence of these sonographic patterns in patients with signs and symptoms suggestive of pneumonia significantly increases the probability of VAP.

Current practice of lung ultrasonography (LUS) in the diagnosis of pneumothorax: a survey of physician sonographers in Germany.

BACKGROUND: The purpose of this study was to survey the current practice of the use of lung ultrasonography (LUS) in the diagnosis of pneumothorax. METHODS: Physician sonographers, accredited for diagnostic ultrasonography in surgery, anaesthesia and medicine were studied. Questions addressed the frequency of exposure to patients with suspected pneumothorax, frequency of LUS use, preferences regarding technical aspects of LUS examination, assessment of diagnostic accuracy of LUS and involvement in teaching. RESULTS: Of the respondents, 55.1% used LUS 'always' or 'frequently' for suspected pneumothorax. Also, 35.5% of physicians rated LUS as 'always reliable' in ruling out pneumothorax, and 21.3% of respondents rated LUS as 'always reliable' in ruling in pneumothorax. The mode of performing LUS for pneumothorax was highly variable. Statistically significant differences were found regarding the likelihood of LUS usage, the combined use of M-Mode and B-mode scanning and the confidence to exclude pneumothorax based on LUS findings for physicians with frequent exposure to pneumothorax cases. CONCLUSIONS: Physicians' use of LUS in the diagnosis of pneumothorax is modest. Confidence in diagnostic accuracy is not comprehensive. Further research is required to establish the most efficient way of performing LUS in this scenario to achieve the highest possible diagnostic accuracy and reliable documentation of examination results.

Manually controlled total intravenous anesthesia augmented by electrophysiologic monitoring for complex stereotactic neurosurgical procedures.

Stereotactically guided procedures are performed for an ever extending range of conditions. They present a unique anesthetic challenge. In our institution, a standardized anesthetic protocol for total intravenous anesthesia (TIVA) augmented by electrophysiologic monitoring with BIS or AEP monitors was introduced. We conducted a retrospective study of 21 patients (ASA status 2-3) presenting for stereotactically guided procedures who were anesthetized according to the protocol. Median duration of anesthesia was 260 minutes (222 to 325 min); on average 3.0 (1.0 to 4.2) adjustments to the TIVA-protocol were made per patient. Highest and lowest mean arterial blood pressures in relation to baselines were 100% (87.5% to 109.8%) and 68.7% (64.0% to 72.6%), respectively. Likewise highest and lowest heart rates recorded were 106.7% (98.5% to 119.0%) and 75.0% (68.2% to 83.3%). After discontinuation of TIVA, spontaneous breathing returned after 5.0 minutes (4.0 to 8.0 min), extubation was possible after 6.0 minutes (5.0 to 10.0 min) and patients were ready for discharge to the ward after 15.0 minutes (12.0 to 18.0 min). There were no cases of postoperative nausea or vomiting. We found that manually controlled TIVA, augmented by electrophysiologic monitoring, facilitated maintenance of an appropriate depth of anesthesia with stable hemodynamics and excellent recovery times.