Passive leg raising-induced changes in pulse pressure variation to assess fluid responsiveness in mechanically ventilated patients: a multicentre prospective observational study.

BACKGROUND: Passive leg raising-induced changes in cardiac index can be used to predict fluid responsiveness. We investigated whether passive leg raising-induced changes in pulse pressure variation (ΔPPVPLR) can also predict fluid responsiveness in mechanically ventilated patients. METHODS: In this multicentre prospective observational study, we included 270 critically ill patients on mechanical ventilation in whom volume expansion was indicated because of acute circulatory failure. We did not include patients with cardiac arrythmias. Cardiac index and PPV were measured before/during a passive leg raising test and before/after volume expansion. A volume expansion-induced increase in cardiac index of >15% defined fluid responsiveness. To investigate whether ΔPPVPLR can predict fluid responsiveness, we determined areas under the receiver operating characteristic curves (AUROCs) and grey zones for relative and absolute ΔPPVPLR. RESULTS: Of the 270 patients, 238 (88%) were on controlled mechanical ventilation with no spontaneous breathing activity and 32 (12%) were on pressure support ventilation. The median tidal volume was 7.1 (inter-quartile range [IQR], 6.6-7.6) ml kg-1 ideal body weight. One hundred sixty-four patients (61%) were fluid responders. Relative and absolute ΔPPVPLR predicted fluid responsiveness with an AUROC of 0.92 (95% confidence interval [95% CI], 0.88-0.95; P<0.001) each. The grey zone for relative and absolute ΔPPVPLR included 4.8% and 22.6% of patients, respectively. These results were not affected by ventilatory mode and baseline characteristics (type of shock, centre, vasoactive treatment). CONCLUSIONS: Passive leg raising-induced changes in pulse pressure variation accurately predict fluid responsiveness with a small grey zone in critically ill patients on mechanical ventilation. CLINICAL TRIAL REGISTRATION: NCT03225378.

Pathophysiology, mechanisms, and managements of tissue hypoxia.

Oxygen is needed to generate aerobic adenosine triphosphate and energy that is required to support vital cellular functions. Oxygen delivery (DO2) to the tissues is determined by convective and diffusive processes. The ability of the body to adjust oxygen extraction (ERO2) in response to changes in DO2 is crucial to maintain constant tissue oxygen consumption (VO2). The capability to increase ERO2 is the result of the regulation of the circulation and the effects of the simultaneous activation of both central and local factors. The endothelium plays a crucial role in matching tissue oxygen supply to demand in situations of acute drop in tissue oxygenation. Tissue oxygenation is adequate when tissue oxygen demand is met. When DO2 is severely compromised, a critical DO2 value is reached below which VO2 falls and becomes dependent on DO2, resulting in tissue hypoxia. The different mechanisms of tissue hypoxia are circulatory, anaemic, and hypoxic, characterised by a diminished DO2 but preserved capacity of increasing ERO2. Cytopathic hypoxia is another mechanism of tissue hypoxia that is due to impairment in mitochondrial respiration that can be observed in septic conditions with normal overall DO2. Sepsis induces microcirculatory alterations with decreased functional capillary density, increased number of stopped-flow capillaries, and marked heterogeneity between the areas with large intercapillary distance, resulting in impairment of the tissue to extract oxygen and to satisfy the increased tissue oxygen demand, leading to the development of tissue hypoxia. Different therapeutic approaches exist to increase DO2 and improve microcirculation, such as fluid therapy, transfusion, vasopressors, inotropes, and vasodilators. However, the effects of these agents on microcirculation are quite variable.

Thoracic surgery in United Arab Emirates.

The United Arab Emirates (UAE) has undergone a significant change in its population and economy in the last decades and in parallel its healthcare system has evolved rapidly to provide advanced, innovative and world-leading care. At the forefront of this revolution in healthcare is the development of a multidisciplinary multimodality thoracic service provision, offered at quaternary referral hospitals amalgamating academics, training, research and innovation. Previously, thoracic service care was limited to single providers at various public and private hospitals, usually performing lower complexity cases. Most complex thoracic cases were repatriated outside the UAE. This practice was replaced with the opening of Cleveland Clinic Abu Dhabi (CCAD), in 2015, which created a multidisciplinary thoracic program. This included the start of a mini-invasive surgical and lung transplantation program. Since that time other public and private hospitals have emerged providing care in a similar model. The impact of these programs has been a decreased transfer of patients abroad for treatment. Under the umbrella of the Emirates Thoracic Society (ETS) a platform for greater collaboration aimed at improving patient care, potential research and physician education has been created. Direct links have been established with world-leading Thoracic surgery and Respiratory Medicine Centers facilitating this development and offering support and guidance. This article charts these changes in thoracic care in the recent past, present, and delineates plans for the future in the UAE.

QT Prolongation in Critically Ill Patients With SARS-CoV-2 Infection.

BACKGROUND: Several reports linked the use of repurposed drugs such as hydroxychloroquine (HCQ), azithromycin, lopinavir/ritonavir, and favipiravir with QT interval prolongation in patients with SARS-CoV2 infection. Little is known about the risk factors for QT interval prolongation in this population. We sought to describe the prevalence and identify the main risk factors associated with clinically significant corrected QT (QTc) prolongation in this population. METHODS: We conducted a retrospective analysis of critically ill patients who were admitted to our intensive care unit (ICU), had at least one electrocardiogram performed during their ICU stay, and tested positive for SARs-CoV-2. Clinically significant QTc interval prolongation was defined as QTc >500 milliseconds (ms). RESULTS: Out of the 111 critically ill patients with SARS-CoV-2 infection, QTc was significantly prolonged in 47 cases (42.3%). Patients with a clinically significant QTc prolongation had significantly higher proportions of history of cardiac diseases/surgery (22 [46.8%] vs. 10 [15.6%], P < .001), hypokalemia (10 [21.3] vs. 5 [7.8%], P = .04), and male gender (95% vs. 82.8%, P = .036) than patients with QTc ≤500 ms, respectively. A total of 46 patients (41.4%) received HCQ, 28 (25.2%) received lopinavir/ritonavir, and 5 (4.5%) received azithromycin. Multivariate logistic regression analysis showed that a history of cardiac disease was the only independent factor associated with clinically significant QTc prolongation (P = .004 for the likelihood-ratio test). CONCLUSION: The prevalence of clinically significant QTc prolongation in critically ill patients with SARS-CoV-2 infection was high and independent of drugs used. Larger prospective observational studies are warranted to elucidate independent risk factors associated with clinically significant QTc prolongation in this study population.

Hypertriglyceridemia in Critically Ill Patients With SARS-CoV-2 Infection.

BACKGROUND: Patients with SARS-CoV-2 infection could develop severe disease requiring critical care admission. Case reports indicated high incidence of hypertriglyceridemia (HTG) in critically ill patients infected with SARS-CoV-2, which might be related to the drugs. OBJECTIVE: We sought to determine the risk factors associated with HTG in this population and to investigate the relationship between HTG and lipase. METHODS: A retrospective observational study was conducted at our hospital between March 1 and June 30, 2020. Patients were included if they were ≥18 years old, admitted to the intensive care unit (ICU), tested positive for SARS-CoV-2, and had triglycerides (TG) checked during their hospital stay. RESULTS: Of the 111 critically ill patients, 103 patients were included. Males comprised 88.3% of the sample. The median TG at baseline was 197.4 (IQR: 139.8-283) mg/dL. The lipase median level at baseline was 23.00 (IQR: 0.00-69.50) IU/L. The results of the mixed-effects logistic regression analysis indicated that patient-level variables, favipiravir use, blood glucose level, and propofol use were significantly associated with HTG. There was no relationship between lipase and TG levels over time. Furthermore, TG concentrations over time showed a similar trend to inflammatory markers. CONCLUSION AND RELEVANCE: The incidence of clinically significant HTG was high and was associated with propofol and favipiravir use. HTG might reflect the high inflammatory state in these patients. Clinicians should look at the full picture before changing therapies based only on HTG. Our findings need to be replicated in a larger prospective study.

Patient-Ventilator Dyssynchrony in Critically Ill Patients.

Patient-ventilator dyssynchrony is a mismatch between the patient's respiratory efforts and mechanical ventilator delivery. Dyssynchrony can occur at any phase throughout the respiratory cycle. There are different types of dyssynchrony with different mechanisms and different potential management: trigger dyssynchrony (ineffective efforts, autotriggering, and double triggering); flow dyssynchrony, which happens during the inspiratory phase; and cycling dyssynchrony (premature cycling and delayed cycling). Dyssynchrony has been associated with patient outcomes. Thus, it is important to recognize and address these dyssynchronies at the bedside. Patient-ventilator dyssynchrony can be detected by carefully scrutinizing the airway pressure-time and flow-time waveforms displayed on the ventilator screens along with assessing the patient's comfort. Clinicians need to know how to depict these dyssynchronies at the bedside. This review aims to define the different types of dyssynchrony and then discuss the evidence for their relationship with patient outcomes and address their potential management.

Convalescent Plasma Efficacy in Life-Threatening COVID-19 Patients Admitted to the ICU: A Retrospective Cohort Study.

(1) Background: There are limited data regarding the efficacy of convalescent plasma (CP) in critically ill patients admitted to the intensive care unit (ICU) due to coronavirus disease 2019 (COVID-19). We aimed to determine whether CP is associated with better clinical outcome among these patients. (2) Methods: A retrospective single-center study including adult patients with laboratory-confirmed SARS-CoV-2 infection admitted to the ICU for acute respiratory failure. The primary outcome was time to clinical improvement, within 28 days, defined as patient discharged alive or reduction of 2 points on a 6-point disease severity scale. (3) Results: Overall, 110 COVID-19 patients were admitted. Thirty-two patients (29%) received CP; among them, 62.5% received at least one CP with high neutralizing antibody titers (≥1:160). Clinical improvement occurred within 28 days in 14 patients (43.7%) of the CP group vs. 48 patients (61.5%) in the non-CP group (hazard ratio (HR): 0.75 (95% CI: 0.41-1.37), p = 0.35). After adjusting for potential confounding factors, CP was not independently associated with time to clinical improvement (HR: 0.53 (95% CI: 0.23-1.22), p = 0.14). Additionally, the average treatment effects of CP, calculated using the inverse probability weights (IPW), was not associated with the primary outcome (-0.14 days (95% CI: -3.19-2.91 days), p = 0.93). Hospital mortality did not differ between CP and non-CP groups (31.2% vs. 19.2%, p = 0.17, respectively). Comparing CP with high neutralizing antibody titers to the other group yielded the same findings. (4) Conclusions: In this study of life-threatening COVID-19 patients, CP was not associated with time to clinical improvement within 28 days, or hospital mortality.

Severe Acute Kidney Injury in Critically Ill Patients with COVID-19 Admitted to ICU: Incidence, Risk Factors, and Outcomes.

BACKGROUND: Critically ill patients with COVID-19 are prone to develop severe acute kidney injury (AKI), defined as KDIGO (Kidney Disease Improving Global Outcomes) stages 2 or 3. However, data are limited in these patients. We aimed to report the incidence, risk factors, and prognostic impact of severe AKI in critically ill patients with COVID-19 admitted to the intensive care unit (ICU) for acute respiratory failure. METHODS: A retrospective monocenter study including adult patients with laboratory-confirmed severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection admitted to the ICU for acute respiratory failure. The primary outcome was to identify the incidence and risk factors associated with severe AKI (KDIGO stages 2 or 3). RESULTS: Overall, 110 COVID-19 patients were admitted. Among them, 77 (70%) required invasive mechanical ventilation (IMV), 66 (60%) received vasopressor support, and 9 (8.2%) needed extracorporeal membrane oxygenation (ECMO). Severe AKI occurred in 50 patients (45.4%). In multivariable logistic regression analysis, severe AKI was independently associated with age (odds ratio (OR) = 1.08 (95% CI (confidence interval): 1.03-1.14), p = 0.003), IMV (OR = 33.44 (95% CI: 2.20-507.77), p = 0.011), creatinine level on admission (OR = 1.04 (95% CI: 1.008-1.065), p = 0.012), and ECMO (OR = 11.42 (95% CI: 1.95-66.70), p = 0.007). Inflammatory (interleukin-6, C-reactive protein, and ferritin) or thrombotic (D-dimer and fibrinogen) markers were not associated with severe AKI after adjustment for potential confounders. Severe AKI was independently associated with hospital mortality (OR = 29.73 (95% CI: 4.10-215.77), p = 0.001) and longer hospital length of stay (subhazard ratio = 0.26 (95% CI: 0.14-0.51), p < 0.001). At the time of hospital discharge, 74.1% of patients with severe AKI who were discharged alive from the hospital recovered normal or baseline renal function. CONCLUSION: Severe AKI was common in critically ill patients with COVID-19 and was not associated with inflammatory or thrombotic markers. Severe AKI was an independent risk factor of hospital mortality and hospital length of stay, and it should be rapidly recognized during SARS-CoV-2 infection.

Effects of Methylprednisolone on Ventilator-Free Days in Mechanically Ventilated Patients with Acute Respiratory Distress Syndrome and COVID-19: A Retrospective Study.

Objectives: There are limited data regarding the efficacy of methylprednisolone in patients with acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19) requiring invasive mechanical ventilation. We aimed to determine whether methylprednisolone is associated with increases in the number of ventilator-free days (VFDs) among these patients. Design: Retrospective single-center study. Setting: Intensive care unit. Patients: All patients with ARDS due to confirmed SARS-CoV-2 infection and requiring invasive mechanical ventilation between 1 March and 29 May 2020 were included. Interventions: None. Measurements and Main Results: The primary outcome was ventilator-free days (VFDs) for the first 28 days. Defined as being alive and free from mechanical ventilation. The primary outcome was analyzed with competing-risks regression based on Fine and Gray's proportional sub hazards model. Death before day 28 was considered to be the competing event. A total of 77 patients met the inclusion criteria. Thirty-two patients (41.6%) received methylprednisolone. The median dose was 1 mg·kg-1 (IQR: 1-1.3 mg·kg-1) and median duration for 5 days (IQR: 5-7 days). Patients who received methylprednisolone had a mean 18.8 VFDs (95% CI, 16.6-20.9) during the first 28 days vs. 14.2 VFDs (95% CI, 12.6-16.7) in patients who did not receive methylprednisolone (difference, 4.61, 95% CI, 1.10-8.12, p = 0.001). In the multivariable competing-risks regression analysis and after adjusting for potential confounders (ventilator settings, prone position, organ failure support, severity of the disease, tocilizumab, and inflammatory markers), methylprednisolone was independently associated with a higher number of VFDs (subhazards ratio: 0.10, 95% CI: 0.02-0.45, p = 0.003). Hospital mortality did not differ between the two groups (31.2% vs. 28.9%, p = 0.82). Hospital length of stay was significantly shorter in the methylprednisolone group (24 days [IQR: 15-41 days] vs. 37 days [IQR: 23-52 days], p = 0.046). The incidence of positive blood cultures was higher in patients who received methylprednisolone (37.5% vs. 17.8%, p = 0.052). However, 81% of patients who received methylprednisolone also received tocilizumab. The number of days with hyperglycemia was similar in the two groups. Conclusions: Methylprednisolone was independently associated with increased VFDs and shortened hospital length of stay. The combination of methylprednisolone and tocilizumab was associated with a higher rate of positive blood cultures. Further trials are needed to evaluate the benefits and safety of methylprednisolone in moderate or severe COVID-19 ARDS.

Pulmonary cavitation: an under-recognized late complication of severe COVID-19 lung disease.

BACKGROUND: Pulmonary radiological findings of the novel coronavirus disease 2019 (COVID-19) have been well documented and range from scattered ground-glass infiltrates in milder cases to confluent ground-glass change, dense consolidation, and crazy paving in the critically ill. However, lung cavitation has not been commonly described in these patients. The objective of this study was to assess the incidence of pulmonary cavitation in patients with COVID-19 and describe its characteristics and evolution. METHODS: We conducted a retrospective review of all patients admitted to our institution with COVID-19 and reviewed electronic medical records and imaging to identify patients who developed pulmonary cavitation. RESULTS: Twelve out of 689 (1.7%) patients admitted to our institution with COVID-19 developed pulmonary cavitation, comprising 3.3% (n = 12/359) of patients who developed COVID-19 pneumonia, and 11% (n = 12/110) of those admitted to the intensive care unit. We describe the imaging characteristics of the cavitation and present the clinical, pharmacological, laboratory, and microbiological parameters for these patients. In this cohort six patients have died, and six discharged home. CONCLUSION: Cavitary lung disease in patients with severe COVID-19 disease is not uncommon, and is associated with a high level of morbidity and mortality.

Hydroxychloroquine is associated with slower viral clearance in clinical COVID-19 patients with mild to moderate disease.

ABSTRACT: There are conflicting data regarding the use of hydroxychloroquine (HCQ) in COVID-19 hospitalized patients. The objective of this study was to assess the efficacy of HCQ in increasing SARS-CoV-2 viral clearance.Hospitalized adult patients with confirmed SARS-CoV-2 infection were retrospectively included in the study. The primary outcome was the time from a confirmed positive nasopharyngeal swab to turn negative. A negative nasopharyngeal swab conversion was defined as a confirmed SARS-CoV-2 case followed by 2 negative results using RT-PCR assay with samples obtained 24 hours apart. Multiple linear regression analysis was used to adjust for potential confounders.Thirty-four confirmed COVID-19 patients completed the study. Nineteen (55.9%) patients presented with symptoms, and 14 (41.2%) had pneumonia. Only 21 (61.8%) patients received HCQ. The time to SARS-CoV-2 negativity nasopharyngeal test was significantly longer in patients who received HCQ than those who did not receive HCQ [17 (13-21) vs 10 (4-13) days, P = .023]. HCQ was independently associated with time to negativity test after adjustment for potential confounders (symptoms, comorbidities, antiviral drugs, pneumonia, or oxygen therapy) in multivariable Cox proportional hazards regression analysis (hazard ratio = 0.33, 95% confidence interval: 0.13-0.9, P = .024). On day 14, 47.8% (14/23) patients tested negative in the HCQ group compared with 90.9% (10/11) patients who did not receive HCQ (P = .016).HCQ was associated with a slower viral clearance in COVID-19 patients with mild to moderate disease. Data from ongoing randomized clinical trials with HCQ should provide a definitive answer regarding the efficacy and safety of this treatment.

Tocilizumab Use in a Chronic Hemodialysis Patient for the Management of COVID-19-Associated Pneumonia and Acute Respiratory Distress Syndrome.

Novel coronavirus disease 2019 (COVID-19) is a highly infectious, rapidly spreading viral disease. As of writing this article, there are over 4.4 million people affected by COVID-19, and unfortunately, 300,000 have succumbed to the infection. In this article, we address a particularly more susceptible group of the population of end-stage renal disease (ESRD) patients on dialysis who may potentially benefit from being treated with tocilizumab. The use of tocilizumab has not been reported widely in ESRD patients on dialysis to treat COVID-19. In this case report, we describe a patient with ESRD on hemodialysis who was admitted to the intensive care unit, with severe pneumonia secondary to COVID-19 infection. This patient was treated with tocilizumab 400 mg intravenous and had a favorable outcome with no apparent adverse events.

Thrombotic events following tocilizumab therapy in critically ill COVID-19 patients: a Façade for prognostic markers.

BACKGROUND: Hospitals in the Middle East Gulf region have experienced an influx of COVID-19 patients to their medical wards and intensive care units. The hypercoagulability of these patients has been widely reported on a global scale. However, many of the experimental treatments used to manage the various complications of COVID-19 have not been widely studied in this context. The effect of the current treatment protocols on patients' diagnostic and prognostic biomarkers may thus impact the validity of the algorithms adopted. CASE PRESENTATION: In this case series, we report four cases of venous thromboembolism and 1 case of arterial thrombotic event, in patients treated with standard or intensified prophylactic doses of unfractionated heparin or low molecular weight heparin at our institution. Tocilizumab has been utilized as an add-on therapy to the standard of care to treat patients with SARS-CoV-2 associated acute respiratory distress syndrome, in order to dampen the hyperinflammatory response. It is imperative to be aware that this drug may be masking the inflammatory markers (e.g. IL6, CRP, fibrinogen, and ferritin), without reducing the risk of thrombotic events in this population, creating instead a façade of an improved prognostic outcome. However, the D-dimer levels remained prognostically reliable in these cases, as they were not affected by the drug and continued to be at the highest level until event occurrence. CONCLUSIONS: In the setting of tocilizumab therapy, traditional prognostic markers of worsening infection and inflammation, and thus potential risk of acute thrombosis, should be weighed carefully as they may not be reliable for prognosis and may create a façade of an improved prognostic outcome insteasd. Additionally, the fact that thrombotic events continued to be observed despite decrease in inflammatory markers and the proactive anticoagulative approach adopted, raises more questions about the coagulative mechanisms at play in COVID-19, and the appropriate management strategy.

Peripheral pulmonary artery stenosis as a cause of pulmonary hypertension in adults.

Peripheral pulmonary artery stenosis (PPAS) is an underrecognized condition in the adult population. PPAS can lead to pulmonary hypertension but is likely misdiagnosed as either idiopathic pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension. We retrospectively identified adult patients with PPAS either in its isolated form or related to other congenital defects from January 1998 to September 2012. We reviewed the patients' clinical data by using our hospital electronic medical records and/or their paper charts. We identified 6 adult patients with PPAS with an age range of 16-56 years (1 woman and the rest men). Presenting signs and symptoms were thoracic murmurs, progressive dyspnea, and syncope. Three patients had Williams-Beuren syndrome. Pulmonary angiography showed that PPAS was predominantly located in main branches or lobar pulmonary arteries in 5 patients, while in 1 patient the arterial narrowing was at the level of the segmental pulmonary arteries. Right heart catheterization showed a mean pulmonary artery pressure (PAP) ranging from 35 to 60 mmHg. Balloon dilation was performed in all patients, predominantly in the lobar arteries, and it caused a decrease in mean PAP that ranged from 16% to 46% in 5 patients. In 1 patient the mean PAP did not decrease. All but 1 patient had follow-up echocardiograms at 1 year that showed stable echocardiographic findings. Pulmonary hypertension due to PPAS continues to presents a diagnostic challenge. Therefore, a high index of suspicion during the initial evaluation of pulmonary hypertension is essential for its prompt diagnosis and adequate treatment.