Stephan Katzenschlager

Hyperspectral imaging (HSI) is a non-invasive technology capable of assessing microcirculatory impairment. This study evaluated whether HSI can detect early microcirculatory alterations in trauma patients and differentiate between those with hemodynamic instability or stability during initial trauma resuscitation. In this prospective single-center observational study at a German level I trauma center (01/2023–10/2024), patients underwent HSI (TIVITA ^® 2.0) at three time points: during the primary survey, after resuscitation room care, and 24 h after admission. HSI approximates four microcirculatory parameters: tissue oxygenation saturation (StO₂), tissue water index (TWI), tissue hemoglobin index (THI), and near-infrared perfusion index (NIR). Hemodynamic instability was defined as systolic blood pressure < 90 mmHg for > 10 min, catecholamine use > 10 min, or pronounced clinical signs of hypoperfusion. The primary outcome was the difference in StO₂ between patients with and without hemodynamic instability at the initial HSI measurement. Secondary outcomes included comparison of all HSI parameters between groups, correlations with Injury Severity Score (ISS), biomarkers (lactate, bicarbonate, base excess), and mortality. Statistical analyses comprised t-tests, receiver operator curve (ROC) analyses, diagnostic accuracy, and DeLong’s test. A total of 163 patients were analyzed (18 hemodynamic instability, 145 hemodynamic stability). No significant difference in initial StO₂ was observed between groups (hemodynamic instability: 56.50 (SD 17.08) vs. hemodynamic stability: 59.48 (SD 10.92); p = 0.311). Likewise, TWI, THI, and NIR showed no significant differences. Initial elevated lactate levels (≥ 2 mmol/L) were associated with significantly lower StO ₂ levels ( p = 0.002). ROC analysis of StO₂ for predicting in-hospital mortality showed an area under the curve of 0.677 (95% CI 0.529–0.825). The optimal mortality cut-off (StO₂ ≤ 54%) demonstrated a sensitivity of 0.70, specificity of 0.66, positive predictive value of 0.22, and negative predictive value (NPV) of 0.94. AUCs of StO₂, lactate, bicarbonate, and base excess overlapped, with no significant pairwise differences. HSI did not discriminate between hemodynamically unstable and stable patients at initial trauma assessment but correlated well with high lactate levels. However, its high NPV for mortality suggests potential value as an objective, non-invasive tool for early trauma team downgrading. Trial registration: German Clinical Trials Register (DRKS ID DRKS00030986) on 27th December 2022.

Background: Despite stabilizing macrocirculatory blood pressure, vasopressors may deleteriously affect microcirculatory perfusion in critically ill patients. As microcirculatory dysfunction is associated with adverse outcomes and objective bedside monitoring remains limited, hyperspectral imaging (HSI) has emerged as a promising noninvasive method to assess tissue oxygenation. This study investigated the association between load of vasoactive medication and microcirculatory impairment using HSI in critically ill patients. Methods: In this secondary analysis of the prospective HySpec-ICU study, 502 surgical ICU patients were included. HSI measurements of the hand were performed on the day of admission to determine tissue oxygenation (StO₂) and other HSI variables. Multivariable linear regression and mediation analysis were employed to investigate the association between Norepinephrine Equivalent (NEE) and StO₂ and its impact on serum lactate levels. Results: Higher NEE was independently associated with significantly lower StO₂ (B = − 0.0931, β=−0.193, p = 0.001), while MAP showed no significant correlation with StO₂. Patients in the highest NEE quartile (> 0.28) exhibited the lowest StO₂ and the highest 30-day mortality (41.8%). StO₂ partially mediated the relationship between vasopressor load and arterial lactate. StO₂ generally improved after shock reversal defined as NEE ≤ 0.05, lactate < 2mmol/l, MAP ≥ 65mmHg for at least 24 h (+ 5.8%, p < 0.001). Conclusion: High vasopressor requirements are associated with impaired microcirculatory oxygenation of the hand regardless of systemic blood pressure. HSI provides an objective bedside tool to monitor these alterations, potentially identifying patients with persistent microcirculatory shock who require intensified therapy beyond macrohemodynamic targets.

Second-generation supraglottic airway devices (SADs) are widely used alternatives to endotracheal intubation in both anesthesia and emergency airway management. The newly developed LT®evo represents a redesigned version of the established Laryngeal Tube Suction Disposable (LTS-D). This study compared the ventilatory performance of the LT®evo with endotracheal intubation and three other second-generation SADs— LTS-D, Ambu® AuraGain™ and i-gel® Plus—using a controlled human cadaver model. In this prospective, randomized experiment, six thawed adult cadavers were sequentially ventilated via an endotracheal tube (ET) and four SADs under standardized mechanical ventilation (tidal volume 7 mL/kg, PEEP 5 cmH₂O, respiratory rate 10/min). Airway pressure and flow were continuously recorded (sampling rate 200 Hz) to determine inspiratory tidal volume, pressure, flow, and calculated resistance. Endotracheal intubation using fiberoptics was attempted via LT®evo , AuraGain™ and i-gel® Plus. Data were analyzed using Kruskal–Wallis tests with Holm-corrected post-hoc pairwise comparisons. From six human cadavers (60–85kg estimated body weight), 30 complete ventilation datasets were obtained. Initial fiberoptic control of SAD placement showed optimal positioning in 13 of 24 insertions. During ventilation cycles, inspiratory tidal volumes of the LT®evo (0.49 [0.46–0.52]) were similar to those of ET, AuraGain™ and LTS-D and superior to those of the i-gel® Plus (0.31 L [0.27–0.33], p < 0.001). Peak inspiratory pressure and inspiratory resistance were higher in ET when compared to LT®evo and all other SADs. Endotracheal intubation using fiberoptics was successful in all attempts via LT®evo , AuraGain™ and i-gel® Plus. In this controlled cadaver study, the newly designed LT®evo demonstrated ventilatory performance comparable to that of the LTS-D and the Ambu® AuraGain ^TM and was superior to the i-gel® Plus in delivering adequate tidal volumes. Additionally, LT®evo allowed for fiberoptic ET placement. Importantly, these results are specific to the cadaveric model and reflect technical variability in ventilation mechanics rather than clinical effectiveness. Clinical trial number German Clinical Trials Registry, DRKS00038309, on October 30 ^th , 2025.

Background: Transesophageal echocardiography during out-of-hospital cardiac arrest can be performed during ongoing chest compressions and may improve resuscitation quality, but its prehospital use has not been systematically evaluated. To assess the feasibility, diagnostic yield, and impact of prehospital TEE on resuscitation metrics and advanced life support (ALS) interventions during OHCA. Methods: We conducted a randomized controlled trial in a physician-staffed two-tiered emergency medical service (EMS). Adults with ongoing non-traumatic OHCA were randomized 1:1 to standard ALS or ALS plus TEE. The primary endpoints were hands-off time and chest compression fraction (CCF) from EMS arrival to return of spontaneous circulation (ROSC) or resuscitation termination. Secondary endpoints included ROSC at hospital admission, survival to hospital discharge, neurological status at hospital discharge, and TEE findings. Analyses followed the intention-to-treat principle. Results: Of 249 screened patients, 35 were randomized and 32 analyzed (TEE n = 15; control n = 17). Median hands-off time was 4 s in both groups. Mean CCF was higher in the TEE group (96.2%) than the control group (91.6%), with a mean difference of 4.6% (95% confidence interval 2.5–6.7; p < 0.001). Sustained ROSC occurred in 40% (TEE) versus 71% (control; p = 0.083). The control group had an eCPR rate of 41%, compared to 20% in the TEE group. Using TEE, an incorrect area of maximal compression or inadequate depth was identified in 23% and 14%, respectively. Conclusion: Prehospital TEE during OHCA was feasible without negatively interfering with CPR metrics, and provided clinically relevant diagnostic information and procedural guidance, warranting further evaluation in larger trials. Trial registration: German Clinical Trials Register DRKS00028695 registered on 28 April 2022.