Intensive Care Medicine Experimental最新文献

Background: Enhancing venous return during cardiopulmonary resuscitation (CPR) can lead to better hemodynamics and improved outcome after cardiac arrest (CA). Peripheral Intravenous Analysis (PIVA) provides feedback on venous flow changes and may indicate an increase in venous return and cardiac output during CPR. We hypothesize PIVA can serve as an early indicator of increased venous return, preceding end-tidal CO₂ (etCO₂) increase, before the return of spontaneous circulation (ROSC) in a rat model of CA and CPR.

Results: Eight male Wistar rats were intubated and ventilated, and etCO₂ was measured. Vessels were cannulated in the tail vein, femoral vein, femoral artery, and central venous and connected to pressure transducers. Ventilation was discontinued to achieve asphyxial CA. After 8 min, CPR began with ventilation, epinephrine, and automated chest compressions 200 times per minute until mean arterial pressure increased to 120 mmHg. Waveforms were recorded and analyzed. PIVA was calculated using a Fourier transformation of venous waveforms. Data are mean ± SE. Maximum PIVA values occurred in the tail vein 34.7 ± 2.9 s before ROSC, with subsequent PIVA peaks in femoral vein and centrally at 30.9 ± 5.4 and 25.1 ± 5.0 s, respectively. All PIVA peaks preceded etCO₂ increase (21.5 ± 3.2 s before ROSC).

Conclusion: PIVA consistently detected venous pressure changes prior to changes in etCO₂. This suggests that PIVA has the potential to serve as an important indicator of venous return and cardiac output during CPR, and also as a predictor of ROSC.

Background: Sepsis remains a major global health concern due to its high prevalence and mortality. Changes in body temperature (Tb), such as hypothermia or fever, are diagnostic indicators and play a crucial role in the pathophysiology of sepsis. This study aims to characterize the thermoregulatory mechanisms during sepsis using the cecal ligation and puncture (CLP) model and explore how sepsis severity and ambient temperature (Ta) influence Tb regulation and mortality. Rats were subjected to mild or severe sepsis by CLP while housed at thermoneutral (28 °C) or subthermoneutral (22 °C) Ta, and their Tb was monitored for 12 h. Blood and hypothalamus were collected for cytokines and prostaglandin E₂ (PGE₂) analysis.

Results: At 28 °C, febrile response magnitude correlated with sepsis severity and inflammatory response, with tail vasoconstriction as the primary heat retention mechanism. At 22 °C, Tb was maintained during mild sepsis but dropped during severe sepsis, linked to reduced UCP1 expression in brown adipose tissue and less effective vasoconstriction. Despite differences in thermoregulatory responses, both Ta conditions induced a persistent inflammatory response and increased hypothalamic PGE₂ production. Notably, mortality in severe sepsis was significantly higher at 28 °C (80%) compared to 22 °C (0%).

Conclusions: Our findings reveal that ambient temperature and the inflammatory burden critically influence thermoregulation and survival during early sepsis. These results emphasize the importance of considering environmental factors in preclinical sepsis studies. Although rodents in experimental settings are often adapted to cold environments, these conditions may not fully translate to human sepsis, where cold adaptation is rare. Thus, researchers should carefully consider these variables when designing experiments and interpreting translational implications.

Background: Post-intensive care syndrome (PICS) poses a notable public health concern, with survivors of critical illness experiencing long-term physical, psychological, and cognitive challenges. Mitochondrial dysfunction has gained attention for its potential involvement in PICS. However, the long-term impact of mitochondrial status on patient recovery remains uncertain. A single-centre retrospective analysis was conducted in Leeuwarden, the Netherlands, between May and November 2019, within a mixed ICU survivor cohort. Patients were assessed for mitochondrial markers (mtDNA damage represented by the presence of mtDNA fragmentation and mitochondrial DNA levels evaluated by the ratio of mtDNA and nuclear DNA), clinical factors, and long-term outcomes measured by the physical functioning (PF) domain of health-related quality of life.

Results: A total of 43 patients were included in this study divided into recovery and non-recovery groups based on age-adjusted PF scores at 12 months post-ICU. Nineteen patients scored below these thresholds. No significant differences in mitochondrial markers between groups were identified. Furthermore, no significant correlations were found between mtDNA levels and mtDNA damage at baseline and 12 months with PF scores. However, mtDNA levels decreased over time in the recovery (p-value <  < 0.01) and non-recovery groups (p-value < 0.01).

Conclusion: No significant correlation was found between mitochondrial markers and physical functioning scores. This study underscores the multifactorial nature of PICS and the need for a comprehensive understanding of its metabolic and cellular components. While mitochondrial markers may play a role in PICS, they operate within a framework influenced by various factors. This exploratory study serves as a foundation for future investigations aimed at developing targeted interventions to enhance the quality of life for ICU survivors grappling with PICS.

Background: Septic encephalopathy is frequent but its pathophysiology is enigmatic. We studied expression of neurotransmitters, inflammation and integrity of the blood-brain barrier (BBB) in several brain regions during abdominal sepsis. We compared mice with either lethal or surviving phenotype in the first 4 sepsis days. Mature CD-1 females underwent cecal ligation and puncture (CLP). Body temperature (BT) was measured daily and predicted-to-die (within 24 h) mice (for P-DIE; BT < 28 °C) were sacrificed together (1:1 ratio) with mice predicted-to-survive (P-SUR; BT > 35 °C), and healthy controls (CON). Brains were dissected into neocortex, cerebellum, midbrain, medulla, striatum, hypothalamus and hippocampus.

Results: CLP mice showed an up to threefold rise of serotonin in the hippocampus, 5-hydroxyindoleacetic and homovanillic acid (HVA) in nearly all regions vs. CON. Compared to P-SUR, P-DIE mice showed a 1.7 to twofold rise of HVA (386 ng/g of tissue), dopamine (265 ng/g) and 3,4-Dihydroxyphenylacetic acid (DOPAC; 140 ng/g) in the hippocampus, hypothalamus and medulla (174, 156, 82 ng/g of tissue, respectively). CLP increased expression of TNFα, IL-1β and IL-6 mRNA by several folds in the midbrain, cerebellum and hippocampus versus CON. The same cytokines were further elevated in P-DIE vs P-SUR in the midbrain and cerebellum. Activation of astrocytes and microglia was robust across regions but remained typically phenotype independent. There was a similar influx of sodium fluorescein across the BBB in both P-DIE and P-SUR mice.

Conclusions: Compared to survivors, the lethal phenotype induced a stronger deregulation of amine metabolism and cytokine expression in selected brain regions, but the BBB permeability remained similar regardless of the predicted outcome.

Background: Diabetic ketoacidosis (DKA) is a potentially life-threatening disorder associated with severe alterations in metabolism and acid-base status. Mitochondrial dysfunction is associated with diabetes and its complications. Thiamine and coenzyme Q10 (CoQ10) are important factors in aerobic metabolism. In this study, we measured cellular oxygen consumption rates (OCRs) and the effects of in vitro administration of thiamine and CoQ10 on OCRs in patients with DKA versus healthy controls.

Methods: Blood samples were collected from a prospective cohort of patients with DKA and from controls. Cellular OCRs were measured in peripheral blood mononuclear cells (PBMC) without treatment and after treatment with thiamine, CoQ10, or both. The mitochondrial profile was measured using an XFe96 Extracellular Flux Analyzer and XF Cell Mito Stress Test Kit (Seahorse Bioscience). A linear quantile mixed model was used to compare OCRs and estimate treatment effects.

Results: A total of 62 patients with DKA and 48 controls were included in the study. The median basal and maximal OCRs were lower in the DKA group than in the control group (basal: 4.7 [IQR: 3.3, 7.9] vs. 7.9 [5.0, 9.5], p = 0.036; maximal: 16.4 [9.5, 28.1] vs. 31.5 [20.6, 46.0] pmol/min/µg protein, p < 0.001). In DKA samples, basal and maximal OCRs were significantly increased when treated with thiamine, CoQ10, or both. In controls, basal and maximal OCR were significantly increased only with thiamine treatment.

Conclusion: Mitochondrial metabolic profiles of patients with DKA demonstrated lower cellular oxygen consumption when compared to healthy controls. Oxygen consumption increased significantly in cells of patients with DKA treated with thiamine or CoQ10. These results suggest that thiamine and CoQ10 could potentially have therapeutic benefits in DKA via their metabolic effects on mitochondrial cellular respiration.

Background: Quantification of pulmonary edema in patients with acute respiratory distress syndrome (ARDS) by chest computed tomography (CT) scan has not been validated in routine diagnostics due to its complexity and time-consuming nature. Therefore, the single-indicator transpulmonary thermodilution (TPTD) technique to measure extravascular lung water (EVLW) has been used in the clinical setting. Advances in artificial intelligence (AI) have now enabled CT images of inhomogeneous lungs to be segmented automatically by an intensive care physician with no prior radiology training within a relatively short time. Nevertheless, there is a paucity of data validating the quantification of pulmonary edema using automated lung segmentation on CT compared with TPTD.

Methods: A retrospective study (January 2016 to December 2021) analyzed patients with ARDS, admitted to the intensive care unit of the Department of Anesthesiology and Critical Care Medicine, University Hospital Mannheim, who underwent a chest CT scan and hemodynamic monitoring using TPTD at the same time. Pulmonary edema was estimated using manually and automated lung segmentation on CT and then compared to the pulmonary edema calculated from EVLW determined using TPTD.

Results: 145 comparative measurements of pulmonary edema with TPTD and CT were included in the study. Estimating pulmonary edema using either automated lung segmentation on CT or TPTD showed a low bias overall (- 104 ml) but wide levels of agreement (upper: 936 ml, lower: - 1144 ml). In 13% of the analyzed CT scans, the agreement between the segmentation of the AI algorithm and a dedicated investigator was poor. Manual segmentation and automated segmentation adjusted for contrast agent did not improve the agreement levels.

Conclusions: Automated lung segmentation on CT can be considered an unbiased but imprecise measurement of pulmonary edema in mechanically ventilated patients with ARDS.

Background: Escherichia coli is the most common cause of human bloodstream infections and bacterial sepsis/septic shock. However, translation of preclinical septic shock resuscitative therapies remains limited mainly due to low-fidelity of available models in mimicking clinical illness. To overcome the translational barrier, we sought to replicate sepsis complexity by creating an acutely critically-ill preclinical bacterial septic shock model undergoing active 48-h intensive care management.

Aim: To develop a clinically relevant large-animal (ovine) live-bacterial infusion model for septic shock.

Methods: Septic shock was induced by intravenous infusion of the live antibiotic resistant extra-intestinal pathogenic E. coli sequence type 131 strain EC958 in eight anesthetised and mechanically ventilated sheep. A bacterial dose range of 2 × 10⁵-2 × 10⁹ cfu/mL was used for the dose optimisation phase (n = 4) and upon dose confirmation the model was developed (n = 5). Post-shock the animals underwent an early-vasopressor and volume-restriction resuscitation strategy with active haemodynamic management and monitoring over 48 h. Serial blood samples were collected for testing of pro-inflammatory (IL-6, IL-8, VEGFA) and anti-inflammatory (IL-10) cytokines and hyaluronan assay to assess endothelial integrity. Tissue samples were collected for histopathology and transmission electron microscopy.

Results: The 2 × 10⁷ cfu/mL bacterial dose led to a reproducible distributive shock within a pre-determined 12-h period. Five sheep were used to demonstrate consistency of the model. Bacterial infusion led to development of septic shock in all animals. The baseline mean arterial blood pressure reduced from a median of 91 mmHg (71, 102) to 50 mmHg (48, 57) (p = 0.004) and lactate levels increased from a median of 0.5 mM (0.3, 0.8) to 2.1 mM (2.0, 2.3) (p = 0.02) post-shock. The baseline median hyaluronan levels increased significantly from 25 ng/mL (18, 86) to 168 ng/mL (86, 569), p = 0.05 but not the median vasopressor dependency index which increased within 1 h of resuscitation from zero to 0.39 mmHg^-1 (0.06, 5.13), p = 0.065, and. Over the 48 h, there was a significant decrease in the systemic vascular resistance index (F = 7.46, p = 0.01) and increase in the pro-inflammatory cytokines [IL-6 (F = 8.90, p = 0.02), IL-8 (F = 5.28, p = 0.03), and VEGFA (F = 6.47, p = 0.02)].

Conclusions: This critically ill large-animal model was consistent in reproducing septic shock and will be applied in investigating advanced resuscitation and therapeutic interventions.