This overview addresses the pathophysiology of the acute respiratory distress syndrome (ARDS; conventional vs. COVID), the use of oxygen high flow (HFN) vs. noninvasive ventilation (NIV; conventional vs. helmet) and a multimodal approach to avoid endotracheal intubation (“intubation”): low normal temperature, cooperative sedation, normalized systemic and microcirculation, anti-inflammation, reduced lung water, upright position, lowered intra-abdominal pressure.
Increased ventilatory muscle activity (“respiratory drive”) is observed in early ARDS, at variance with ventilatory fatigue observed in decompensated chronic obstructive pulmonary disease (COPD). This increased drive leads to impending then overt ventilatory failure. Therefore, muscle relaxation presents little rationale and should be replaced by lowering the excessive respiratory drive, increased work of breathing, continued or increased labored breathing, self-induced lung injury (SILI), i.e. preserving spontaneous breathing. As CMV is a lifesaver in the setting of failure but does not heal the lung, side-effects of intubation, controlled mechanical ventilation (CMV), paralysis and deep sedation are to be avoided. Additionally, critical care resources shortage requires practice changes.
Therefore, NIV should be routine when addressing immune-compromised patients. The SARS-CoV2 pandemics extended this approach to most patients, which are immune-compromised: elderly, obese, diabetic, etc. The early COVID is a pulmonary vascular endothelial inflammatory disease requiring lower positive-end-expiratory pressure than the typical pulmonary alveolar epithelial inflammatory diffuse ARDS. This leads one to reassess a) the technique of NIV b) the sedation regimen facilitating continuous and extended NIV to avoid intubation. Autonomic, circulatory, respiratory, ventilatory physiology is hierarchized under HFN/NIV and cooperative sedation (dexmedetomidine, clonidine). A prospective randomized pilot trial, then a larger trial are required to ascertain our working hypotheses.
Tag Archives: ARDS
Clinical Profile and Course of Patients with Acute Respiratory Distress Syndrome due to Covid-19 in a Middle-Income Region in Mexico
Introduction: COVID-19 leads to severe clinical complications that culminate in respiratory failure and acute respiratory distress syndrome (ARDS). Despite reports of some comorbidities that contribute to the development of COVID-19-mediated ARDS, there is great variation in mortality rates among critical COVID-19 patients in the world. To date, no studies have described the incidence and comorbidities associated with ARDS due to COVID-19 in the northeastern region of Mexico.
Aim of the study: To describe patients diagnosed with ARDS due to COVID-19 in the northeastern region of Mexico, as well as its variations in comparison with other regions of the country.
Material and Methods: We conducted a prospective and observational study in a tertiary care center in Northeastern Mexico. All patients diagnosed with SARS-CoV-2 infection and requiring management in the intensive care unit were included. We developed a database that was updated daily with the patients´ demographic information, pre-existing diseases, disease severity, and clinical variables.
Results: The incidence of ARDS secondary to COVID-19 in HRAEV was high in comparison with other reports. Diabetes mellitus was the risk factor most associated with COVID-19-mediated ARDS.
Conclusion: Based on our findings and those previously reported in the literature, there are differences that we discuss between northeastern and central Mexico, and analyze other areas evaluated around the world.
Longitudinal Assessment of ROX and HACOR Scores to Predict Non-Invasive Ventilation Failure in Patients with SARS-CoV-2 Pneumonia
Introduction: NIV (Non-invasive ventilation) and HFNC (High Flow nasal cannula) are being used in patients with acute respiratory failure. HACOR score has been exclusively calculated for patients on NIV, on other hand ROX index is being used for patients on HFNC. This is first study where ROX index has been used in patients on NIV to predict failure.
Aim of the study: This study investigates the comparative diagnostic performance of HACOR score and ROX index to predict NIV failure.
Methods: We performed a retrospective cohort study of non-invasively ventilated Covid 19 patients admitted between 1st April 2020 to 15th June 2021 to ICU of a tertiary care teaching hospital located in Central India. We assessed factors responsible for NIV failure, and whether these scores HACOR/ ROX index have discriminative capacity to predict risk of invasive mechanical ventilation.
Results: Of the 441 patients included in the current study, 179 (40.5%) recovered, while remaining 262 (59.4%) had NIV failure. On multivariable analysis, ROX index > 4.47 was found protective for NIV-failure (OR 0.15 (95%CI 0.03-0.23; p<0.001). Age > 60 years and SOFA score were other significant independent predictors of NIV-failure. The AUC for prediction of failure rises from 0.84 to 0.94 from day 1 to day 3 for ROX index and from 0.79 to 0.92 for HACOR score in the same period, hence ROX score was non-inferior to HACOR score in current study. DeLong’s test for two correlated ROC curves had insignificant difference expect day-1 (D1: 0.03 to 0.08; p=3.191e-05 ,D2: -0.002 to 0.02; p = 0.2671, D3: -0.003 to 0.04; p= 0.1065).
Conclusion: ROX score of 4.47 at day-3 consists of good discriminatory capacity to predict NIV failure. Considering its non-inferiority to HACOR score, the ROX score can be used in patients with acute respiratory failure who are on NIV.
Risk Factors for Weaning Failure in COVID-19 Patients
Background: Data on risk factors associated with mechanical ventilation (MV) weaning failure among SARS-CoV2 ARDS patients is limited. We aimed to determine clinical characteristics associated with weaning outcome in SARS-CoV2 ARDS patients under MV.
Objectives: To determine potential risk factors for weaning outcome in patients with SARS-CoV2 ARDS.
Methods: A retrospective observational study was conducted in the ICUs of four Greek hospitals via review of the electronic medical record for the period 2020-2021. All consecutive adult patients were screened and were included if they fulfilled the following criteria: a) age equal or above 18 years, b) need for MV for more than 48 hours and c) diagnosis of ARDS due to SARS-CoV2 pneumonia or primary or secondary ARDS of other aetiologies. Patient demographic and clinical characteristics were recorded for the first 28 days following ICU admission. The primary outcome was weaning success defined as spontaneous ventilation for more than 48 hours.
Results: A hundred and fifty eight patients were included; 96 SARS-CoV2 ARDS patients. SOFA score, Chronic Obstructive Pulmonary Disease (COPD) and shock were independently associated with the weaning outcome OR(95% CI), 0.86 (0.73-0.99), 0.27 (0.08-0.89) and 0.30 (0.14-0.61), respectively]. When we analysed data from SARS-CoV2 ARDS patients separately, COPD [0.18 (0.03-0.96)] and shock [0.33(0.12 – 0.86)] were independently associated with the weaning outcome.
Conclusions: The presence of COPD and shock are potential risk factors for adverse weaning outcome in SARS-CoV2 ARDS patients.
Lung Injury Risk in Traumatic Brain Injury Managed With Optimal Cerebral Perfusion Pressure Guided-Therapy
Introduction: Management of traumatic brain injury (TBI) has to counterbalance prevention of secondary brain injury without systemic complications, namely lung injury. The potential risk of developing acute respiratory distress syndrome (ARDS) leads to therapeutic decisions such as fluid balance restriction, high PEEP and other lung protective measures, that may conflict with neurologic outcome. In fact, low cerebral perfusion pressure (CPP) may induce secondary ischemic injury and mortality, but disproportionate high CPP may also increase morbidity and worse lung compliance and hypoxia with the risk of developing ARDS and fatal outcome. The evaluation of cerebral autoregulation at bedside and individualized (optimal CPP) CPPopt-guided therapy, may not only be a relevant measure to protect the brain, but also a safe measure to avoid systemic complications.
Aim of the study: We aimed to study the safety of CPPopt-guided-therapy and the risk of secondary lung injury association with bad outcome.
Methods and results: Single-center retrospective analysis of 92 severe TBI patients admitted to the Neurocritical Care Unit managed with CPPopt-guided-therapy by PRx (pressure reactivity index). During the first 10 days, we collected data from blood gas, ventilation and brain variables. Evolution along time was analyzed using linear mixed-effects regression models. 86% were male with mean age 53±21 years. 49% presented multiple trauma and 21% thoracic trauma. At hospital admission, median GCS was 7 and after 3-months GOS was 3. Monitoring data was CPP 86±7mmHg, CPP-CPPopt -2.8±10.2mmHg and PRx 0.03±0.19. The average PFratio (PaO2/FiO2) was 305±88 and driving pressure 15.9±3.5cmH2O. PFratio exhibited a significant quadratic dependence across time and PRx and driving pressure presented significant negative association with PFRatio. CPP and CPPopt did not present significant effect on PFratio (p=0.533; p=0.556). A significant positive association between outcome and the difference CPP-CPPopt was found.
Conclusion: Management of TBI using CPPopt-guided-therapy was associated with better outcome and seems to be safe regarding the development of secondary lung injury.
Variability of Steroid Prescription for COVID-19 Associated Pneumonia in Real-Life, Non-Trial Settings
The RECOVERY study documented lower 28-day mortality with the use of dexamethasone in hospitalized patients on invasive mechanical ventilation or oxygen with COVID-19 Pneumonia. We aimed to examine the practice patterns of steroids use, and their impact on mortality and length of stay in ICU. We retrospectively examined records of all patients with confirmed Covid 19 pneumonia admitted to the ICU of Dubai hospital from January 1st, 2020 – June 30th, 2020. We assigned patients to four groups (No steroids, low dose, medium dose, and high dose steroids). The primary clinical variable of interest was doses of steroids. Secondary outcomes were 28-day mortality and length of stay in ICU”. We found variability in doses of steroid treatment. The most frequently used dose was the high dose. Patients who survived were on significantly higher doses of steroids and had significantly longer stays in ICU. The prescription of steroids in Covid-19 ARDS is variable. The dose of steroids impacts mortality rate and length of stay in ICU, although patients treated with high dose steroids seem to stay more days in ICU.
Bronchoscopic Intrapulmonary Recombinant Factor VIIa for Diffuse Alveolar Hemorrhage- induced Acute Respiratory Failure in MPO-ANCA Vasculitis: A Case Report
Introduction: Diffuse alveolar haemorrhage (DAH) is a potentially life-threatening disease, characterized by diffuse accumulation of red blood cells within the alveoli. It can be caused by a variety of disorders. In case DAH results in severe respiratory failure, veno-venous extracorporeal membrane oxygenation (VV-ECMO) can be required. Since VV-ECMO coincides with the need for anticoagulation therapy, this results in a major clinical challenge in DAH patients with hemoptysis.
Case presentation: We report a patient case with severe DAH-induced acute respiratory failure and hemoptysis in need for VV-ECMO complicated by life-threatening membrane oxygenator thrombosis. The DAH-induced hemoptysis was successfully treated with local bronchoscopic recombinant factor VIIa (rFVIIa), allowing systemic anticoagulation to prevent further membrane oxygenator thrombosis. Neither systemic clinical side effects nor differences in the serum coagulation markers occured after applying recombinant factor VIIa (rFVIIa) treatment endobronchially.
Conclusion: This is, to our knowledge, the first case that reports the use of rFVIIa in a patient with DAH due to vasculitis and in need for VV-ECMO complicated by membrane oxygenator thrombosis.
Clinical Characteristics and Outcomes of COVID-19 Acute Respiratory Distress Syndrome Patients Requiring Invasive Mechanical Ventilation in a Lower Middle-Income Country
Background: Covid-19 related acute respiratory distress syndrome (ARDS) requires intensive care, which is highly expensive in lower-income countries. Outcomes of COVID-19 patients requiring invasive mechanical ventilation in Pakistan have not been widely reported. Identifying factors forecasting outcomes will help decide optimal care levels and prioritise resources.
Methods: A single-centre, retrospective study on COVID-19 patients requiring invasive mechanical ventilation was conducted from 1st March to 31st May 2020. Demographic variables, physical signs, laboratory values, ventilator parameters, complications, length of stay, and mortality were recorded. Data were analysed in SPSS ver.23.
Results: Among 71 study patients, 87.3% (62) were males, and 12.7% (9) were females with a mean (SD) age of 55.5(13.4) years. Diabetes mellitus and hypertension were the most common comorbidities in 54.9% (39) patients. Median(IQR) SOFA score on ICU admission and at 48 hours was 7(5-9) and 6(4-10), and median (IQR) APACHE-II score was 15 (11-24) and 13(9-23), respectively. Overall, in-hospital mortality was 57.7%; 25% (1/4), 55.6% (20/36) and 64.5% (20/31) in mild, moderate, and severe ARDS, respectively. On univariate analysis; PEEP at admission, APACHE II and SOFA score at admission and 48 hours; Acute kidney injury; D-Dimer>1.5 mg/L and higher LDH levels at 48 hours were significantly associated with mortality. Only APACHE II scores at admission and D-Dimer levels> 1.5 mg/L were independent predictors of mortality on multivariable regression (p-value 0.012 & 0.037 respectively). Admission APACHE II scores, Area under the ROC curve for mortality was 0.80 (95%CI 0.69-0.90); sensitivity was 77.5% and specificity 70% (cut-off ≥13.5).
Conclusion: There was a high mortality rate in severe ARDS. The APACHE II score can be utilised in mortality prediction in COVID-19 ARDS patients. However, larger-scale studies in Pakistan are required to assess predictors of mortality.