Non-occlusive mesenteric ischaemia: the prevalent cause of gastrointestinal infarction in patients with severe burn injuries.

BACKGROUND: Gastrointestinal complications occur frequently in intensive care patients with severe burns. Intestinal infarction and its deleterious consequences result in high mortality despite rapid surgical intervention. Our objective was to evaluate the aetiology of gastrointestinal infarction in intensive care patients with severe burns. STUDY DESIGN: We retrospectively evaluated all of the severe-burn victims at the burn unit of the Medical University of Vienna from 01/2002 to 06/2012 for whom a gastrointestinal infarction was diagnosed during their inpatient stay on computed-tomography, in the context of acute laparotomy, or upon autopsy by aetiology. RESULTS: After a severe thermal injury, 17 patients suffered a gastrointestinal infarction during their stay. In 82% of those patients, non-occlusive mesenteric ischaemia (NOMI) was identified as the cause of the gastrointestinal infarction. Patients with an embolic infarction tended to be older (78.0years embolism vs. 53.4 NOMI, mean, p<0.01), with a lower abbreviated burn severity index (8.7 embolism vs. 10.4 NOMI, mean, p<0.02) and a smaller total body surface area burned (20% embolism vs. 48% NOMI, mean, p<0.01) than those with a non-occlusive mesenterial ischaemia. No patients with an embolic infarction or any of the females in the entire gastrointestinal infarction group survived this event, resulting in a mortality rate of 100% for the embolic infarction group and female group. The decisive factor for surviving a NOMI was age (median age: male survivors 28years vs. nonsurvivors 66years (of this median, males=72years and females=60years), p<0.02). CONCLUSION: The results of our study clearly demonstrate that in severe-burn intensive care patients, non-occlusive mesenteric ischaemia is the most frequent cause of gastrointestinal infarction and that the decisive factor for survival is the patient's age.

Development of demographics and outcome of very old critically ill patients admitted to intensive care units.

PURPOSE: To evaluate the development of demographics and outcome of very old (>80 years) critically ill patients admitted to intensive care units. SETTING: All consecutive patients admitted to 41 Austrian intensive care units (ICUs) over an 11-year period. METHODS: We performed a retrospective cohort study of prospectively collected data. To compare parameters over time, patients were divided into three groups (group I from 1998 until 2001, group II from 2002 to 2004, and group III from 2005 to 2008). RESULTS: A total of 17,126 patients older than 80 years of age were admitted over the study period. The proportion of very old patients increased from 11.5% (I) to 15.3% (III) with a significant higher prevalence of females in all groups (on average 63.2%). Severity of illness also increased over time, even when corrected for age. Use of noninvasive mechanical ventilation increased over the years. However, risk-adjusted mortality rates [observed-to-expected (O/E) ratios] decreased from 1.14 [confidence interval (CI) 1.11-1.18] to 1.02 (CI 0.99-1.05). This improvement in outcome was confirmed on multivariate analysis: for every year delay in ICU admission, the odds to die decreased by 3%. Moreover, females exhibited a better outcome compared with males. CONCLUSIONS: The relative and absolute numbers of very old patients increased over the study period, as did the severity of illness. Despite this, risk-adjusted hospital mortality improved over the study period. Females dominated in the very old patients and exhibited moreover a better outcome compared with males.

Intrinsic positive end-expiratory pressure at various frequencies of supraglottic jet ventilation in a model of dynamic upper airway obstruction.

BACKGROUND: Supraglottic jet ventilation (JV(S)) with injectors above airway stenoses may result in inadvertent high lung pressures. We designed this study to investigate intrinsic positive end-expiratory pressure (PEEP(i)) during jet ventilation via a distant injector in a model of dynamic upper airway obstruction. METHODS: Respiratory pressure-time curves were recorded during JV(S) in a tracheal lung model using a pig's trachea and an embolectomy catheter's air-filled balloon to simulate 60 and 80% airway obstruction. JV(S) was performed at various jet frequencies (F(jet) 30 min(-1), 60 min(-1), and 100 min(-1)) and driving pressures (1 bar and 2 bar). RESULTS: JV(S) was associated with generation of PEEP(i), which depended on driving pressure, the degree of obstruction, and on ventilatory frequency. CONCLUSIONS: In the presence of a dynamic upper airway obstruction, JV(S) via a distant injector may result in PEEP(i), which cannot be detected when airway pressure is measured in front of the obstruction.

Airway stenosis-related increase of pulmonary pressure during high-frequency jet ventilation depends on injector's position.

BACKGROUND: High-frequency jet ventilation (HFJV) can lead to high-airway pressures under certain conditions. In this laboratory study, we evaluated the influence of the injector's position relative to a fixed airway obstruction on peak pressures in a tracheal-lung model. METHODS: We administered HFJV via a metal jet injector at varying distances from connectors simulating laryngotracheal airway stenosis. Peak pressures were measured inside the lung model. RESULTS: When the jet nozzle was near the simulated stenosis, peak pressure within the test lung increased and reached a maximum when the stenosis' lumen decreased despite unchanged parameters of jet gas flow. With the injector's tip placed 8-10 cm in front of the stenosis, reduction of airway diameter did not result in an increase of distal peak pressures. These observations were similar for all settings of gas flow (0.5-1.5 bar driving pressure) and frequencies. CONCLUSION: This study in a lung model suggests that placing an injector more than 8 cm proximal to a laryngotracheal stenosis will prevent changes in intrapulmonary pressure related to the degree of stenosis or driving pressure during HFJV. The location of the injector chosen for clinical care should balance the need for effective ventilation with the risk of barotrauma.