Impact Of Mechanical Ventilation Research Articles

Impact of mechanical ventilation on severe acute kidney injury in critically ill patients with and without COVID-19 – a multicentre propensity matched analysis

BackgroundAcute kidney injury (AKI) is common in critically ill patients and is associated with increased morbidity and mortality. Its complications often require renal replacement therapy (RRT). Invasive mechanical ventilation (IMV) and infections are considered risk factors for the occurrence of AKI. The use of IMV and non-invasive ventilation (NIV) has changed over the course of the pandemic. Concomitant with this change in treatment a reduction in the incidences of AKI and RRT was observed. We aimed to investigate the impact of IMV on RRT initiation by comparing critically ill patients with and without COVID-19. Furthermore, we wanted to investigate the rates and timing of RRT as well as the outcome of patients, who were treated with RRT.ResultsA total of 8,678 patients were included, of which 555 (12.8%) in the COVID-19 and 554 (12.8%) in the control group were treated with RRT. In the first week of ICU stay the COVID-19 patients showed a significantly lower probability for RRT initiation (day 1: p < 0.0001, day 2: p = 0.021). However, after day 7 a reversed HR was found. In mechanically ventilated patients the risk was significantly higher for the initiation of RRT over the entire stay. While in non-COVID-19 patients this was a non-significant trend, in COVID-19 patients the risk for RRT was significantly increased. The median delay between initiation of IMV and requirement of RRT was observed to be longer in COVID-19 patients (5 days [IQR: 2–11] vs. 2 days [IQR: 1–5]). The analysis restricted to patients with RRT showed a significantly higher risk for ICU death in patients requiring IMV compared to patients without IMV.ConclusionThe analysis demonstrated that IMV as well as COVID-19 are associated with an increased risk for initiation of RRT. The association between IMV and risk of RRT initiation was given for all investigated time intervals. Additionally, COVID-19 patients showed an increased risk for RRT initiation during the entire ICU stay within patients admitted to an ICU due to respiratory disease. In COVID-19 patients treated with RRT, the risk of death was significantly higher compared to non-COVID-19 patients.

Mechanical ventilation during extracorporeal membrane oxygenation support - New trends and continuing challenges.

The impact of mechanical ventilation on the survival of patients supported with veno-venous extracorporeal membrane oxygenation (V-V ECMO) due to severe acute respiratory distress syndrome (ARDS) remains still a focus of research. Recent guidelines, randomized trials, and registry data underscore the importance of lung-protective ventilation during respiratory and cardiac support on ECMO. This approach includes decreasing mechanical power delivery by reducing tidal volume and driving pressure as much as possible, using low or very low respiratory rate, and a personalized approach to positive-end expiratory pressure (PEEP) setting. Notably, the use of ECMO in awake and spontaneously breathing patients is increasing, especially as a bridging strategy to lung transplantation. During respiratory support in V-V ECMO, native lung function is of highest importance and adjustments of blood flow on ECMO, or ventilator settings significantly impact the gas exchange. These interactions are more complex in veno-arterial (V-A) ECMO configuration and cardiac support. The fraction on delivered oxygen in the sweep gas and sweep gas flow rate, blood flow per minute, and oxygenator efficiency have an impact on gas exchange on device side. On the patient side, native cardiac output, native lung function, carbon dioxide production (VCO2), and oxygen consumption (VO2) play a role. Avoiding pulmonary oedema includes left ventricle (LV) distension monitoring and prevention, pulse pressure >10mm Hg and aortic valve opening assessment, higher PEEP adjustment, use of vasodilators, ECMO flow adjustment according to the ejection fraction, moderate use of inotropes, diuretics, or venting strategies as indicated and according to local expertise and resources. Understanding the physiological principles of gas exchange during cardiac support on femoro-femoral V-A ECMO configuration and the interactions with native gas exchange and haemodynamics are essential for the safe applications of these techniques in clinical practice. Proning during ECMO remains to be discussed until further data is available from prospective, randomized trials implementing individualized PEEP titration during proning.

Impact of Mechanical Ventilation on COVID-19 Patients in the Intensive Care Unit: A Retrospective Study

Abstract Introduction: Mechanical ventilation is frequently utilised in critically ill COVID-19 patients, yet outcomes remain unclear. This study evaluated characteristics, outcomes and associations between mechanical ventilation and prognosis in COVID-19 patients admitted to the intensive care unit (ICU). Methods: A retrospective review was conducted of medical records from 1389 COVID-19 patients admitted to a single ICU between dates. Demographic, clinical, treatment data and outcomes including length of stay (LOS), microbiological cure and discharge status were collected. Comparisons were made between ventilated and non-ventilated patients. Results: The mean age was 56 years, 74% were male. Mechanical ventilation was utilised in 73.9% for a mean duration of 9.89 days. Ventilated patients had significantly longer ICU (15 days vs. 10 days) and hospital stays (22 days vs. 18 days). Microbiological cure was achieved in 16.1%, with higher rates in ventilated patients. Factors including older age, male gender, diabetes and higher body mass index correlated with worse outcomes. Ventilated patients more often experienced ICU (96% vs. 4%) and hospital mortality (60% vs. 40%). Mechanical ventilation duration positively correlated with ICU and hospital LOS. Longer ventilation durations correlated with cure and remaining in ICU. Conclusion: In this large cohort, mechanical ventilation was commonly utilised yet correlated with worse outcomes, although outcomes may be confounded by indication. Modifying risk profiles through glycaemic and weight control along with standardised evidence-based protocols may help optimise outcomes. Further prospective analyses accounting for the severity of illness are needed to determine causal relationships between ventilation and prognosis in COVID-19.

Impact of mechanical ventilation on clinical outcomes in ICU-admitted Alzheimer's disease patients: a retrospective cohort study.

Alzheimer's disease (AD) is increasingly recognized as a pressing global public health issue, demanding urgent development of scientific AD management strategies. In recent years, the proportion of AD patients in Intensive Care Units (ICU) has been on the rise. Simultaneously, the use of mechanical ventilation (MV) is becoming more prevalent among this specific patient group. Considering the pathophysiological characteristics of AD, the application of MV in AD patients may lead to different outcomes. However, due to insufficient research data, the significant impact of MV on the prognosis of AD patients in the ICU remains unclear. Therefore, we conducted this study to comprehensively evaluate the potential influence of MV on the survival rate of AD patients in the ICU. We obtained data from the MIMIC-IV database for patients diagnosed with AD. Using propensity score matching (PSM), we paired patients who received MV treatment with those who did not receive treatment. Next, we conducted Cox regression analysis to evaluate the association between MV and in-hospital mortality, 7-day mortality, 28-day mortality, 90-day mortality, 4-year mortality, length of hospital stay, and ICU stay. The data analysis involved a cohort of 641 AD patients spanning from 2008 to 2019, inclusive. Following a 1:2 propensity score matching (PSM) procedure, 300 patients were successfully paired, comprising 123 individuals who underwent MV treatment and 177 who did not. MV demonstrated an association with an elevated risk of in-hospital mortality (HR 5.782; 95% CI 2.981-11.216; p < 0.001), 7-day mortality (HR 6.353; 95% CI 3.014-13.392; p < 0.001), 28-day mortality (HR 3.210; 95% CI 1.977-5.210; p < 0.001), 90-day mortality (HR 2.334; 95% CI 1.537-3.544; p < 0.001), and 4-year mortality (HR 1.861; 95% CI 1.370-2.527; p < 0.001). Furthermore, it was associated with a prolonged length of ICU stay [3.6(2.2,5.8) vs. 2.2(1.6,3.7); p = 0.001]. In the subgroup analysis, we further confirmed the robustness of the results obtained from the overall population. Additionally, we observed a significant interaction (p-interaction <0.05) between age, admission type, aspirin use, statin use, and the use of MV. In patients with AD who are receiving treatment in the ICU, the use of MV has been linked to higher short-term, medium-term, and long-term mortality rates, as well as prolong ICU stays. Therefore, it is crucial to break away from conventional thinking and meticulously consider both the medical condition and personal preferences of these vulnerable patients. Personalized treatment decisions, comprehensive communication between healthcare providers and patients, formulation of comprehensive treatment plans, and a focus on collaboration between the ICU and community organizations become imperative.

Numerical performance of CO2 accumulation and droplet dispersion from a cough inside a hospital lift under different ventilation strategies

The impact of mechanical ventilation on airborne diseases is not completely known. The recent pandemic of COVID-19 clearly showed that additional investigations are necessary. The use of computational tools is an advantage that needs to be included in the study of designing safe places. The current study focused on a hospital lift where two subjects were included: a healthy passenger and an infected one. The elevator was modelled with a fan placed on the middle of the ceiling and racks for supplying air at the bottom of the lateral wall. Three ventilation strategies were evaluated: a without ventilation case, an upwards-blowing exhausting fan case and a downwards-blowing fan case. Five seconds after the elevator journey began, the infected person coughed. For the risk assessment, the CO2 concentration, droplet removal performance and dispersion were examined and compared among the three cases. The results revealed some discrepancies in the selection of an optimal ventilation strategy. Depending on the evaluated parameter, downward-ventilation fan or no ventilation strategy could be the most appropriate approach.

Bidirectional pressure: a mini review of ventilator-lung-kidney interactions.

Acute kidney injury and respiratory failure that requires mechanical ventilation are both common complications of critical illnesses. Failure of either of these organ systems also increases the risk of failure to the other. As a result, there is a high incidence of patients with concomitant acute kidney injury and the need for mechanical ventilation, which has a devasting impact on intensive care unit outcomes, including mortality. Despite decades of research into the mechanisms of ventilator-lung-kidney interactions, several gaps in knowledge remain and current treatment strategies are primarily supportive. In this review, we outline our current understanding of the mechanisms of acute kidney injury due to mechanical ventilation including a discussion of; 1) The impact of mechanical ventilation on renal perfusion, 2) activation of neurohormonal pathways by positive pressure ventilation, and 3) the role of inflammatory mediators released during ventilator induced lung injury. We also provide a review of the mechanisms by which acute kidney injury increases the risk of respiratory failure. Next, we outline a summary of the current therapeutic approach to preventing lung and kidney injury in the critically ill, including fluid and vasopressor management, ventilator strategies, and treatment of acute kidney injury. Finally, we conclude with a discussion outlining opportunities for novel investigations that may provide a rationale for new treatment approaches.

Diaphragm Dysfunction and ICU-Acquired Weakness in Septic Shock Patients with or without Mechanical Ventilation: A Pilot Prospective Observational Study.

Sepsis is a risk factor for diaphragm dysfunction and ICU-acquired weakness (ICU-AW); however, the impact of mechanical ventilation (MV) on these relationships has not been thoroughly investigated. This study aimed to compare the incidence of diaphragm dysfunction and ICU-AW in patients with septic shock, with and without MV. We conducted a single-center prospective observational study that included consecutive patients diagnosed with septic shock admitted to the ICU between March 2021 and February 2022. Ultrasound measurements of diaphragm thickness and manual measurements of limb muscle strength were repeated after ICU admission. The incidences of diaphragm dysfunction and ICU-AW, as well as their associations with clinical outcomes, were compared between patients with MV and without MV (non-MV). Twenty-four patients (11 in the MV group and 13 in the non-MV group) were analyzed. At the final measurements in the MV group, eight patients (72.7%) had diaphragm dysfunction, and six patients (54.5%) had ICU-AW. In the non-MV group, 10 patients (76.9%) had diaphragm dysfunction, and three (23.1%) had ICU-AW. No association was found between diaphragm dysfunction and clinical outcomes. Patients with ICU-AW in the MV group had longer ICU and hospital stays. Among patients with septic shock, the incidence of diaphragm dysfunction was higher than that of ICU-AW, irrespective of the use of MV. Further studies are warranted to examine the association between diaphragm dysfunction and clinical outcomes.

Impact of Mechanical Ventilation and Renal Replacement Therapy on Clinical Outcomes among Critically Ill COVID-19 Patients

Background: Poor clinical outcomes in patients with severe COVID-19 occur due to many factors that require elucidation. The objective of this study was to describe the outcomes of critically ill patients with COVID-19 and identify the risk factors for mortality. Materials and Methods: The study was a single-centered cross-sectional, observational study involving COVID-19 patients admitted to the intensive care units (ICUs) of a tertiary care hospital in the Middle East and North Africa (MENA) region. The patients were admitted between 1 March and 31 December 2020. Logistic regression analysis was used to identify risk factors for mortality. Results: Of 107 patients admitted, 98 (91.6%) were ≥40 years old and 84 (78.5%) were males. The mean oxygen saturation at admission was 79.6 ± 12.6%, the duration of ICU stay was 13.0 ± 11.6 days, and 65 (60.7%) of the patients received mechanical ventilation. Major comorbidities included hypertension (57%), diabetes (56%), and chronic kidney disease (CKD) (15.5%). The overall mortality rate was 51.4%; this was higher in patients who received mechanical ventilation (60 vs. 38.1%; p = 0.03) and those with co-morbid hypertension (60.7 vs. 39.1%; p = 0.03). Risk factors for mortality were: need for mechanical ventilation agent of record adjusted Odds ratio (aOR) 4.4 (1.6–12.6), co-morbid hypertension aOR 5.8 (1.6–21.1), having CKD aOR 5.4 (1.2–25.6) and receiving renal replacement therapy aOR 4.3 (1.4–13.0). Conclusions: The use of mechanical ventilation or renal replacement therapy among critically ill COVID-19 patients could potentially predict worse outcomes. Patients with existing hypertension or CKD may carry a higher mortality risk.

Personalized lung-protective ventilation in children – Is it possible?

Mechanical ventilation, while life-saving, can be associated with risks of exacerbating existing lung injury or causing new injury. An understanding of how mechanical ventilation can injure the lung and other systems is important to develop an optimal ventilatory approach. Over the past 70 years, different mechanisms that can cause lung injury have been described with putative suggestions for lung protection. Which mechanisms are operating in a particular patient is difficult to ascertain at the bedside. Guidelines have been formulated for both adults and children for the management of patients on mechanical ventilation with acute respiratory distress syndrome. Lung protection is the main objective of these guidelines. Lung disease is not homogeneous within the lung, and between patients with the same diagnosis. Response to ventilatory parameters also differs based on the distribution of injured and uninjured lungs, being beneficial in some but harmful in others. The impact of mechanical ventilation on the cardiovascular system and other systems is also variable. It is important to understand that these guidelines are one-size-fits-all therapeutic suggestions. While guidelines are useful, it is important to personalize mechanical ventilation based on the patient’s lung mechanics and their response to adjustments of the ventilatory parameters. This chapter will review the current knowledge of the factors that contribute to injury to the lungs from mechanical ventilation. At the end of the review, I have formulated a personalized approach to lung protection during invasive mechanical ventilation for patients with parenchymal lung disease – a consensus of one.

Acute kidney injury outcomes in covid-19 patients: systematic review and meta-analysis.

Acute kidney injury (AKI) is a frequent complication of coronavirus-19 disease (COVID-19). Therefore, we decided to perform a systematic review and meta-analysis with data from the literature to relate the development of COVID-19 associated-AKI with comorbidities, medications, and the impact of mechanical ventilation. We performed a systematic review using the Newcastle-Ottawa scale and a meta-analysis using the R program. Relevant studies were searched in the PubMed, Medline, and SciELO electronic databases. Search filters were used to include reports after 2020 and cohort studies. In total, 1166 articles were identified and 55 English-written articles were included based on the risk of bias. Of all COVID-19-hospitalized patients presenting with AKI (n = 18029) classified as Kidney Disease Improving Global Outcomes stage 1 to 3, approximately 18% required mechanical ventilation and 39.2 % died. Around 11.3% of the patients required kidney replacement therapy (KRT) and of these, 1093 died and 321 required continuous KRT. Death is more frequent in individuals with AKI [OR 6.03, 95%CI: 5.73-6.74; p<0.01]. Finally, mechanical ventilation is an aggravating factor in the clinical conditions studied [OR 11.01, 95%CI: 10.29-11.77; p<0.01]. Current literature indicates AKI as an important complication in COVID-19. In this context, we observed that comorbidities, such as chronic kidney disease and heart failure, were more related to the development of AKI. In addition, mechanical ventilation was seen as an aggravating factor in this scenario.

When the Renal (Function) Begins to Fall: A Mini-Review of Acute Kidney Injury Related to Acute Respiratory Distress Syndrome in Critically Ill Patients.

Acute kidney injury (AKI) is one of the most frequent causes of organ failure encountered in patients in the intensive care unit (ICU). Because of its predisposition to occur in the most critically ill patients, it is not surprising to observe a high frequency of AKI in patients with acute respiratory distress syndrome (ARDS). However, few studies have been carried out to assess the epidemiology of AKI in subgroups of ARDS patients using recommended KDIGO criteria. Moreover, the mechanisms involved in the physio-pathogenesis of AKI are still poorly understood, in particular the impact of mechanical ventilation on the kidneys. We carried out a review of the literature, focusing on the epidemiology and physiopathology of AKI in patients with ARDS admitted to the ICU. We addressed the importance of clinical management, focusing on mechanical ventilation for improving outcomes, on AKI. Finally, we also propose candidate treatment strategies and management perspectives. Our literature search showed that AKI is particularly common in ICU patients with ARDS. In association with the classic risk factors for AKI, such as comorbidities and iatrogeny, changes in mechanical ventilation parameters, which have been exclusively evaluated for their outcomes on respiratory function and death, must be considered carefully in terms of their impact on the short-term renal prognosis.

Evaluation of the influence of individualized protective ventilation on the lung mechanical properties

The work is devoted to the study of the influence of individualized protective ventilation support on pulmonary mecha-nics. The study included 47 patients who underwent open abdominal surgery under general anesthesia. All patients had a moderate to high risk of developing postoperative pulmonary complications by the ARISCAT scale. Intraoperatively, the impact of individualized protective ventilation on respiratory mechanics, namely Ppeak, Pplat, Pdrive, dynamic pulmonary compliance was assessed. Individualized protective respiratory support was ventilation with a tidal volume of 7 ml/kg of ideal body weight, with the selection of the optimal level of positive pressure at the end of exhalation (PEEP), focusing on dynamic pulmonary compliance and performing recruiting maneuver, and then in the case of a decrease in dynamic pulmonary compliance by more than 20 %, followed by re-selection of PEEP. The studied parameters were recorded before and after the recruiting maneuver, as well as on the 30th, 60th, 90th, 120th, 150th, 180th minutes after the recruiting maneuver, depending on the duration of the operation. The use of alveolar straightening techniques led to an improvement in pulmonary mechanics, namely, an increase in dynamic pulmonary compliance by 16 % and a decrease in Pdrive by 17 %. The intraoperative level of PEEP averaged 4 [4; 5] cm of water. No cases of hypoxemia or recurrence of recruiting maneuver were reported. The obtained results indicate that chosen technique of recruiting maneuver is effective and safe, and its use allows reducing the negative impact of mechanical ventilation. The study did not find a statistically significant correlation between the level of PEEP and the value of dynamic pulmonary compliance. Such data prove the need for individual selection of ventilation parameters according to the characteristics of the mechanical properties of each patient.

Mechanical ventilation at the time of heart transplantation and associations with clinical outcomes.

The impact of mechanical ventilation (MV) at the time of heart transplantation is not well understood. In addition, MV was recently removed as a criterion from the new US heart transplantation allocation system. We sought to assess for the association between MV at transplantation and 1-year mortality. We utilized the United Network for Organ Sharing database and included all adult, single organ heart transplantations from 1990 to 2019. We utilized multivariable logistic regression adjusting for demographics, comorbidities, and markers of clinical acuity. We identified 60 980 patients who underwent heart transplantation, 2.4% (n = 1431) of which required MV at transplantation. Ventilated patients were more likely to require temporary mechanical support, previous dialysis, and had a shorter median waitlist time (21 vs. 95 days, P < 0.001). At 1 year, the mortality was 33.7% (n = 484) for ventilated patients and 11.7% (n = 6967) for those not ventilated at the time of transplantation (log-rank P < 0.001). After multivariable adjustment, patients requiring MV continued to have a substantially higher 90-day [odds ratio (OR) 3.20, 95% confidence interval (CI): 2.79-3.66, P < 0.001] and 1-year mortality (OR 2.67, 95% CI: 2.36-3.03, P < 0.001). For those that survived to 90 days, the adjusted mortality at 1 year continued to be higher (OR 1.48, 95% CI: 1.16-1.89, P = 0.002). We found a strong association between the presence of MV at heart transplantation and 90-day and 1-year mortality. Future studies are needed to identify which patients requiring MV have reasonable outcomes, and which are associated with substantially poorer outcomes.

Serum Creatinine and Serum Cystatin C are Both Relevant Renal Markers to Estimate Vancomycin Clearance in Critically Ill Neonates

Purpose: Serum creatinine (SCr) is used as a marker of kidney function to guide dosing of renally eliminated drugs. Serum Cystatin C (S-CysC) has been suggested as a more reliable kidney marker than SCr in adults and children. Purpose of this study was to investigate S-CysC as alternative renal marker to SCr for estimating vancomycin clearance in neonates undergoing intensive care. Methods: Vancomycin pharmacokinetics (PK), SCr and S-CysC data were collected in patients undergoing vancomycin treatment in the neonatal intensive care unit of Robert Debré Hospital - Paris. A population PK analysis was performed utilizing routine therapeutic drug monitoring samples. S-CysC and SCr were compared as covariates on vancomycin clearance using stepwise covariate modeling (forward inclusion [p < 0.05] and backward elimination [p < 0.01]). Model performance was evaluated by graphical and statistical criteria. Results: A total of 108 vancomycin concentrations from 66 patients (postmenstrual age [PMA] of 26–46 weeks) were modeled with an allometric one-compartment model. The median (range) values for SCr and S-CysC were 41 (12–153) µmol/l and 1.43 (0.95–2.83) mg/l, respectively. Following stepwise covariate model building, SCr was retained as single marker of kidney function (after accounting for weight and PMA) in the final model. Compared to the final model based on SCr, the alternative model based on S-CysC showed very similar performance (e.g. BIC of 578.3 vs. 576.4) but included one additional covariate: impact of mechanical ventilation on vancomycin clearance, in addition to the effects of size and maturation. Conclusion: ill neonates. However, if using S-CysC for this purpose mechanical ventilation needs to be taken into account.

Neuroinflammation, neuronal damage or cognitive impairment associated with mechanical ventilation: A systematic review of evidence from animal studies.

Long-term cognitive impairment is a complication of critical illness survivors. Beside its lifesaving role, mechanical ventilation has potential complications. The aim of this study is to systematically review the evidence collected in animal studies that correlate mechanical ventilation with neuroinflammation, neuronal damage and cognitive impairment. We searched MEDLINE and EMBASE databases for studies published from inception until August 31st, 2020, that enrolled mechanically ventilated animals and reported on neuroinflammation or neuronal damage markers changes or cognitive-behavioural impairment. Of 5583 studies, 11 met inclusion criteria. Mice, rats, pigs were used. Impact of MV: 4 out of 7 studies reported higher neuroinflammation markers in MV-treated animals and 3 studies reported no differences; 7 out of 8 studies reported a higher neuronal damage and 1 reported no differences; 2 out of 2 studies reported cognitive decline up to 3days after MV. Higher Tidal volumes are associated with higher changes in brain or serum markers. Preclinical evidence suggests that MV induces neuroinflammation, neuronal damage and cognitive impairment and these are worsened if sub-optimal MV settings are applied. Future studies, with appropriate methodology, are necessary to evaluate for serum monitoring strategies. CRD42019148935.

Impact of Prolonged Mechanical Ventilation on Ferroptosis in Renal Ischemia/Reperfusion Injury in Rats.

We here investigated the impact of mechanical ventilation (MV) time on ferroptosis in a rat renal ischemia/reperfusion injury (IRI) model. Thirty-two male adult Sprague Dawley rats were divided into four groups (n = 8/group): the sham group, IRI group, IRI+MV-4 h group, and IRI+MV-12 h group. Rats in the IRI group were subjected to 45 min bilateral renal ischemia. Rats in the IRI+MV groups were additionally mechanically ventilated with tracheal intubation after 45 min bilateral renal ischemia. Morphological changes associated with kidney injury and ferroptosis were assessed by hematoxylin and eosin staining and electron microscopy. Levels of the central regulator of ferroptosis, glutathione peroxidase 4 (GPX4), and lipid peroxidation markers 4-hydroxynonenal (4HNE) and superoxide dismutase 2 (SOD2) were determined in the kidney tissue by western blotting. Glutathione (GSH) levels were assessed in the serum and kidney homogenate. Scr levels in the IRI+MV-12 h group were significantly higher than those in the sham, IRI, and IRI+MV-4 h groups (all P < 0.001). Electron microscopy revealed the most pronouncedly abnormal mitochondrial morphology, suggestive of ferroptosis, in the IRI+MV-12 h group. The GPX4 and SOD2 protein levels progressively decreased in the following order: sham group > IRI group > IRI+MV-4 h group > IRI+MV-12 h group (P < 0.05 for all comparisons). By contrast, the 4HNE levels progressively increased in the kidney, with the highest values in the IRI+MV-12 h group (P < 0.05, vs. the IRI group and vs. the IRI+MV-4 h group). Further, the GSH levels in the serum and kidney homogenates were significantly reduced in the IRI+MV-12 h group (P < 0.01, vs. IRI group and vs. the IRI+MV-4 h group). A significant positive correlation was observed between the serum and kidney GSH levels (r2 = 0.542, P = 0.03). These observations suggested that prolonged MV may exacerbate renal function failure, already initiated by IRI, by ferroptosis. Depletion of GSH may contribute to this effect, which requires further investigation.

Влияние искусственной вентиляции легких на гемодинамику у новорожденных

Влияние искусственной вентиляции легких на гемодинамику у новорожденных

Corrigendum to "Determinants of Mortality in Patients with Nosocomial Acinetobacter baumannii Bacteremia in Southwest China: A Five-Year Case-Control Study".

[This corrects the article DOI: 10.1155/2018/3150965.].

Mechanical ventilation causes diaphragm dysfunction in newborn lambs

BackgroundDiaphragm weakness occurs rapidly in adult animals treated with mechanical ventilation (MV), but the effects of MV on the neonatal diaphragm have not been determined. Furthermore, it is unknown whether co-existent lung disease exacerbates ventilator-induced diaphragmatic dysfunction (VIDD). We investigated the impact of MV (mean duration = 7.65 h), either with or without co-existent respiratory failure caused by surfactant deficiency, on the development of VIDD in newborn lambs.MethodsNewborn lambs (1–4 days) were assigned to control (CTL, non-ventilated), mechanically ventilated (MV), and MV + experimentally induced surfactant deficiency (MV+SD) groups. Immunoblotting and quantitative PCR assessed inflammatory signaling, the ubiquitin-proteasome system, autophagy, and oxidative stress. Immunostaining for myosin heavy chain (MyHC) isoforms and quantitative morphometry evaluated diaphragm atrophy. Contractile function of the diaphragm was determined in isolated myofibrils ex vivo.ResultsEqual decreases (25–30%) in myofibrillar force generation were found in MV and MV+SD diaphragms compared to CTL. In comparison to CTL, both MV and MV+SD diaphragms also demonstrated increased STAT3 transcription factor phosphorylation. Ubiquitin-proteasome system (Atrogin1 and MuRF1) transcripts and autophagy indices (Gabarapl1 transcripts and the ratio of LC3B-II/LC3B-I protein) were greater in MV+SD relative to MV alone, but fiber type atrophy was not observed in any group. Protein carbonylation and 4-hydroxynonenal levels (indices of oxidative stress) also did not differ among groups.ConclusionsIn newborn lambs undergoing controlled MV, there is a rapid onset of diaphragm dysfunction consistent with VIDD. Superimposed lung injury caused by surfactant deficiency did not influence the severity of early diaphragm weakness.

Different particle flow patterns from the airways after recruitment manoeuvres using volume-controlled or pressure-controlled ventilation

ObjectivesNoninvasive online monitoring of different particle flows from the airways may serve as an additional tool to assess mechanical ventilation. In the present study, we used a customised PExA, an optical particle counter for monitoring particle flow and size distribution in exhaled air, to analyse airway particle flow for three subsequent days. We compared volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) and performed recruitment manoeuvres (RM).MethodsSix animals were randomised into two groups: half received VCV before PCV and the other half received PCV before VCV. Measurements were taken daily for 1 h in each mode during three subsequent days in six fully anaesthetised domestic pigs. A RM was performed twice daily for 60 s at positive end-expiratory pressure (PEEP) of 10, 4 breaths/min and inspiratory-expiratory ratio (I:E) of 2:1. Measurements were taken for 3 min before the RM, 1 min during the RM and for 3 min after the RM. The particle sizes measured were between 0.48 and 3.37 μm.ResultsA significant stepwise decrease was observed in total particle count from day 1 to day 3, and at the same time, an increase in fluid levels was seen. Comparing VCV to PCV, a significant increase in total particle count was observed on day 2, with the highest particle count occurring during VCV. A significant increase was observed comparing before and after RM on day 1 and 2 but not on day 3. One animal developed ARDS and showed a different particle pattern compared to the other animals.ConclusionsThis study shows the safety and useability of the PExA technique used in conjunction with mechanical ventilation. We detected differences between the ventilation modes VCV and PCV in total particle count without any significant changes in ventilator pressure levels, FiO2 levels or the animals’ vital parameters. The findings during RM indicate an opening of the small airways, but the effect is short lived. We have also showed that VCV and PCV may affect the lung physiology differently during recruitment manoeuvres. These findings might indicate that this technique may provide more refined information on the impact of mechanical ventilation.