Effects of the Prone Position on Regional Neutrophilic Lung Inflammation According to 18F-FDG Pet in an Experimental Ventilator-Induced Lung Injury Model.

ABSTRACT: Ventilator-induced lung injury (VILI) can be life-threatening and it is important to prevent the development of VILI. It remains unclear whether the prone position affects neutrophilic inflammation in the lung regions in vivo, which plays a crucial role in the pathogenesis of VILI. This study aimed to assess the relationship between the use of the prone position and the development of VILI-associated regional neutrophilic lung inflammation. Regional neutrophilic lung inflammation and lung aeration during low tidal volume mechanical ventilation were assessed using in vivo 2-deoxy-2-[(18)F] fluoro-D-glucose (18F-FDG) positron emission tomography and computed tomography in acutely experimentally injured rabbit lungs (lung injury induced by lung lavage and excessive ventilation). Direct comparisons were made among three groups: control, supine, and prone positions. After approximately 7 h, tissue-normalized 18F-FDG uptake differed significantly between the supine and prone positions (SUP: 0.038 ±â€Š0.014 vs. PP: 0.029 ±â€Š0.008, P = 0.038), especially in the ventral region (SUP: 0.052 ±â€Š0.013 vs. PP: 0.026 ±â€Š0.007, P = 0.003). The use of the prone position reduced lung inhomogeneities, which was demonstrated by the correction of the disproportionate rate of voxel gas over the given lung region. The progression of neutrophilic inflammation was affected by the interaction between the total strain (for aeration) and the inhomogeneity. The prone position is effective in slowing down the progression of VILI-associated neutrophilic inflammation. Under low-tidal-volume ventilation, the main drivers of its effect may be homogenization of lung tissue and that of mechanical forces.

Ventilator-associated events: prevalence and mortality in Japan.

BACKGROUND: In 2013, the Centers for Disease Control and Prevention (CDC) issued the concept of the ventilator-associated events (VAEs) as a quality indicator (QI) in the intensive care unit (ICU). A number of studies have been conducted in the United States and other Western countries to evaluate its practicality. However, information on VAEs in non-Western countries is scarce. The purpose of this preliminary study was to illuminate the incidence and associated mortality rate of VAEs in Japan, as a first step in the effort to determine its practicality. METHODS: We conducted a multi-center, retrospective review of patient medical record using VAEs surveillance algorithm. We analyzed 785 patients with ≥2 days of mechanical ventilator (MV), admitted to the ICU at seven urban hospital in Japan. The prevalence of VAEs, including its three subtypes, and in-ICU mortality were researched. RESULTS: Forty-nine VAEs were identified, affecting 5.7% of patients requiring MV for ≥2 days and 6.4 per 1,000 MV days. Mortality in those who developed VAEs was 42.9%, significantly higher than the rest of the cohort (vs. 15.4%, P<0.001). The overall equivalent distribution of the three VAEs subtype incidences was evaluated: the incidences of VAC only, IVAC only and PVAP were 2.20, 1.90 and 2.29 per 1,000 MV days respectively (P=0.933). However, VAE etiology and mortality was facility dependent. ICUs with a large proportion of surgical patients and more severe cases tended to have increased VAE incidence, with a converse decrease in closed ICUs. CONCLUSIONS: The prevalence of VAEs appears low in Japanese ICUs. Nonetheless, mortality was substantially higher in patients who developed VAEs. Although some potential indices of VAEs are suggested to serve as QIs, additional studies to elaborate its practicality would further be required.

Volume-controlled Ventilation Does Not Prevent Injurious Inflation during Spontaneous Effort.

RATIONALE: Spontaneous breathing during mechanical ventilation increases transpulmonary pressure and Vt, and worsens lung injury. Intuitively, controlling Vt and transpulmonary pressure might limit injury caused by added spontaneous effort. OBJECTIVES: To test the hypothesis that, during spontaneous effort in injured lungs, limitation of Vt and transpulmonary pressure by volume-controlled ventilation results in less injurious patterns of inflation. METHODS: Dynamic computed tomography was used to determine patterns of regional inflation in rabbits with injured lungs during volume-controlled or pressure-controlled ventilation. Transpulmonary pressure was estimated by using esophageal balloon manometry [Pl(es)] with and without spontaneous effort. Local dependent lung stress was estimated as the swing (inspiratory change) in transpulmonary pressure measured by intrapleural manometry in dependent lung and was compared with the swing in Pl(es). Electrical impedance tomography was performed to evaluate the inflation pattern in a larger animal (pig) and in a patient with acute respiratory distress syndrome. MEASUREMENTS AND MAIN RESULTS: Spontaneous breathing in injured lungs increased Pl(es) during pressure-controlled (but not volume-controlled) ventilation, but the pattern of dependent lung inflation was the same in both modes. In volume-controlled ventilation, spontaneous effort caused greater inflation and tidal recruitment of dorsal regions (greater than twofold) compared with during muscle paralysis, despite the same Vt and Pl(es). This was caused by higher local dependent lung stress (measured by intrapleural manometry). In injured lungs, esophageal manometry underestimated local dependent pleural pressure changes during spontaneous effort. CONCLUSIONS: Limitation of Vt and Pl(es) by volume-controlled ventilation could not eliminate harm caused by spontaneous breathing unless the level of spontaneous effort was lowered and local dependent lung stress was reduced.

Association of Patient Care with Ventilator-Associated Conditions in Critically Ill Patients: Risk Factor Analysis.

BACKGROUND: Ventilator-associated conditions (VACs), for which new surveillance definitions and methods were issued by the Center for Disease Control and Prevention (CDC), are respiratory complications occurring in conjunction with the use of invasive mechanical ventilation and are related to adverse outcomes in critically ill patients. However, to date, risk factors for VACs have not been adequately established, leading to a need for developing a better understanding of the risks. The objective of this study was to explore care-related risk factors as a process indicator and provide valuable information pertaining to VAC preventive measures. METHODS: This retrospective, single-center, cohort study was conducted in the intensive-care unit (ICU) of a university hospital in Japan. Patient data were automatically sampled using a computerized medical records system and retrospectively analyzed. Management and care-related, but not host-related, factors were exhaustively analyzed using multivariate analysis for risks of VACs. VAC correlation to mortality was also investigated. RESULTS: Of the 3122 patients admitted in the ICU, 303 ventilated patients meeting CDC-specified eligibility criteria were included in the analysis. Thirty-seven VACs (12.2%) were found with a corresponding rate of 12.1 per 1000 ventilator days. Multivariate analysis revealed four variables related to patient care as risk factors for VACs: absence of intensivist participation in management of ventilated patients [adjusted HR (AHR): 7.325, P < 0.001)], using relatively higher driving pressure (AHR: 1.216, P < 0.001), development of edema (AHR: 2.145, P = 0.037), and a larger body weight increase (AHR: 0.058, P = 0.005). Furthermore, this research confirmed mortality differences in patients with VACs and statistically derived risks compared with those without VACs (HR: 2.623, P = 0.008). CONCLUSION: Four risk factors related to patient care were clearly identified to be the key factors for VAC preventive measures.

Food poisoning associated with Kudoa septempunctata.

BACKGROUND: Kudoa septempunctata is a recently identified cause of food poisoning. We report three cases of food poisoning due to ingestion of this parasite. CASE REPORTS: Among the 358 people exposed during the same catered meal, 94 (including our 3 patients) developed vomiting and diarrhea within 1-9 h after ingestion of raw muscle from contaminated aquacultured olive flounders (Paralichthys olivaceus). These symptoms occurred frequently but were temporary; only 1 patient was hospitalized for dehydration and was discharged 2 days later. CONCLUSION: In Japan, cases of food poisoning due to eating olive flounder have increased during recent years. This increase should prompt heightened awareness among clinicians diagnosing food poisoning.

Effectiveness of end-expiratory lung volume measurements during the lung recruitment maneuver for patients with atelectasis.

PURPOSE: The aim of this study was to determine whether the relative change in the end-expiratory lung volume (EELV) obtained by the recruitment maneuver (RM) can serve as an indicator of the change in the P/F ratio. MATERIALS AND METHODS: The effects of the intermittent stepwise increases in the RM (peak inspiratory pressure, 45, 50, and 55 cm H2O) were compared in 21 patients with atelectasis under mechanical ventilation. The EELV, the ratio of arterial oxygen concentration to the fraction of inspired oxygen P/F ratio, and relative change rate (Δ) in these parameters were evaluated after each RM. RESULTS: A greater improvement in the EELV (1157 ± 344 mL vs 1469 ± 396 mL) and P/F ratio (250 ± 99 vs 320 ± 92) was observed after the RM. The ΔEELV was correlated with the ΔP/F ratio (ρ = 0.73, P < .01) and was identified as an accurate predictor of the improvement of the ΔP/F ratio by the receiver operating characteristic curve (the area under the curve, 0.93; P < .01). CONCLUSIONS: These results suggest that the ΔEELV obtained by intermittent stepwise RM can serve as an indicator of the change in the P/F ratio.

Anti-integrin therapy for multiple sclerosis.

Integrins are the foremost family of cell adhesion molecules that regulate immune cell trafficking in health and diseases. Integrin alpha4 mediates organ-specific migration of immune cells to the inflamed brain, thereby playing the critical role in the pathogenesis of multiple sclerosis. Anti-alpha4 integrin therapy aiming to block infiltration of autoreactive lymphocytes to the inflamed brain has been validated in several clinical trials for the treatment of multiple sclerosis. This paper provides readers with an overview of the molecular and structural bases of integrin activation as well as rationale for using anti-alpha4 integrin therapy for multiple sclerosis and then chronicles the rise and fall of this treatment strategy using natalizumab, a humanized anti-alpha4 integrin.