To comprehensively assess published peer-reviewed studies related to extracorporeal membrane oxygenation (ECMO), focusing on outcomes and complications of ECMO in adult patients.
Systematic review ...and meta-analysis.
MEDLINE/PubMed was searched for articles on complications and mortality occurring during or after ECMO.
Included studies had more than 100 patients receiving ECMO and reported in detail fatal or nonfatal complications occurring during or after ECMO. Primary outcome was mortality at the longest follow-up available; secondary outcomes were fatal and non-fatal complications.
Twelve studies were included (1763 patients), mostly reporting on venoarterial ECMO. Criteria for applying ECMO were variable, but usually comprised acute respiratory failure, cardiogenic shock or both. After a median follow-up of 30 days (1st-3rd quartile, 30-68 days), overall mortality was 54% (95% CI, 47%-61%), with 45% (95% CI, 42%-48%) of fatal events occurring during ECMO and 13% (95% CI, 11%-15%) after it. The most common complications associated with ECMO were: renal failure requiring continuous venovenous haemofiltration (occurring in 52%), bacterial pneumonia (33%), any bleeding (33%), oxygenator dysfunction requiring replacement (29%), sepsis (26%), haemolysis (18%), liver dysfunction (16%), leg ischaemia (10%), venous thrombosis (10%), central nervous system complications (8%), gastrointestinal bleeding (7%), aspiration pneumonia (5%), and disseminated intravascular coagulation (5%).
Even with conditions usually associated with a high chance of death, almost 50% of patients receiving ECMO survive up to discharge. Complications are frequent and most often comprise renal failure, pneumonia or sepsis, and bleeding.
Data on the pathology of COVID-19 are scarce; available studies show diffuse alveolar damage; however, there is scarce information on the chronologic evolution of COVID-19 lung lesions. The primary ...aim of the study is to describe the chronology of lung pathologic changes in COVID-19 by using a post-mortem transbronchial lung cryobiopsy approach. Our secondary aim is to correlate the histologic findings with computed tomography patterns. SARS-CoV-2-positive patients, who died while intubated and mechanically ventilated, were enrolled. The procedure was performed 30 min after death, and all lung lobes sampled. Histopathologic analysis was performed on thirty-nine adequate samples from eight patients: two patients (illness duration < 14 days) showed early/exudative phase diffuse alveolar damage, while the remaining 6 patients (median illness duration—32 days) showed progressive histologic patterns (3 with mid/proliferative phase; 3 with late/fibrotic phase diffuse alveolar damage, one of which with honeycombing). Immunohistochemistry for SARS-CoV-2 nucleocapsid protein was positive predominantly in early-phase lesions. Histologic patterns and tomography categories were correlated: early/exudative phase was associated with ground-glass opacity, mid/proliferative lesions with crazy paving, while late/fibrous phase correlated with the consolidation pattern, more frequently seen in the lower/middle lobes. This study uses an innovative cryobiopsy approach for the post-mortem sampling of lung tissues from COVID-19 patients demonstrating the progression of fibrosis in time and correlation with computed tomography features. These findings may prove to be useful in the correct staging of disease, and this could have implications for treatment and patient follow-up.
To study incidence, type, etiology, risk factors, and impact on outcome of nosocomial infections during extracorporeal membrane oxygenation.
Retrospective analysis of prospectively collected data.
...Italian tertiary referral center medical-surgical ICU.
One hundred five consecutive patients who were treated with extracorporeal membrane oxygenation from January 2010 to November 2015.
None.
Ninety-two patients were included in the analysis (48.5 37-56 years old, simplified acute physiology score II 37 32-47) who underwent peripheral extracorporeal membrane oxygenation (87% veno-venous) for medical indications (78% acute respiratory distress syndrome). Fifty-two patients (55%) were infected (50.4 infections/1,000 person-days of extracorporeal membrane oxygenation). We identified 32 ventilator-associated pneumonia, eight urinary tract infections, five blood stream infections, three catheter-related blood stream infections, two colitis, one extracorporeal membrane oxygenation cannula infection, and one pulmonary-catheter infection. G+ infections (35%) occurred earlier compared with G- (48%) (4 2-10 vs. 13 7-23 days from extracorporeal membrane oxygenation initiation; p < 0.001). Multidrug-resistant organisms caused 56% of bacterial infections. Younger age (2-35 years old) was independently associated with higher risk for nosocomial infections. Twenty-nine patients (31.5%) died (13.0 deaths/1,000 person-days of extracorporeal membrane oxygenation). Infected patients had higher risk for death (18 vs. 8 deaths/1,000 person-days of extracorporeal membrane oxygenation; p = 0.037) and longer ICU stay (32.5 19.5-78 vs. 19 10.5-27.5 days; p = 0.003), mechanical ventilation (36.5 20-80.5 vs. 16.5 9-25.5 days; p < 0.001), and extracorporeal membrane oxygenation (25.5 10.75-54 vs. 10 5-13 days; p < 0.001). Older age (> 50 years old), reason for connection different from acute respiratory distress syndrome, higher simplified acute physiology score II, diagnosis of ventilator-associated pneumonia, and infection by multidrug-resistant bacteria were independently associated to increased death rate.
Infections (especially ventilator-associated pneumonia) during extracorporeal membrane oxygenation therapy are common and frequently involve multidrug-resistant organisms. In addition, they have a negative impact on patients' outcomes.
H1N1 influenza can cause severe acute lung injury (ALI). Extracorporeal membrane oxygenation (ECMO) can support gas exchange in patients failing conventional mechanical ventilation, but its role is ...still controversial. We conducted a systematic review and meta-analysis on ECMO for H1N1-associated ALI.
CENTRAL, Google Scholar, MEDLINE/PubMed and Scopus (updated 2 January 2012) were systematically searched. Studies reporting on 10 or more patients with H1N1 infection treated with ECMO were included. Baseline, procedural, outcome and validity data were systematically appraised and pooled, when appropriate, with random-effect methods.
From 1,196 initial citations, 8 studies were selected, including 1,357 patients with confirmed/suspected H1N1 infection requiring intensive care unit admission, 266 (20%) of whom were treated with ECMO. Patients had a median Sequential Organ Failure Assessment (SOFA) score of 9, and had received mechanical ventilation before ECMO implementation for a median of two days. ECMO was implanted before inter-hospital patient transfer in 72% of cases and in most patients (94%) the veno-venous configuration was used. ECMO was maintained for a median of 10 days. Outcomes were highly variable among the included studies, with in-hospital or short-term mortality ranging between 8% and 65%, mainly depending on baseline patient features. Random-effect pooled estimates suggested an overall in-hospital mortality of 28% (95% confidence interval 18% to 37%; I² = 64%).
ECMO is feasible and effective in patients with ALI due to H1N1 infection. Despite this, prolonged support (more than one week) is required in most cases, and subjects with severe comorbidities or multiorgan failure remain at high risk of in-hospital death.
To calculate an index (termed Pmusc/Eadi index) relating the pressure generated by the respiratory muscles (Pmusc) to the electrical activity of the diaphragm (Eadi), during assisted mechanical ...ventilation and to assess if the Pmusc/Eadi index is affected by the type and level of ventilator assistance. The Pmusc/Eadi index was also used to measure the patient's inspiratory effort from Eadi without esophageal pressure.
Crossover study.
One general ICU.
Ten patients undergoing assisted ventilation.
Pressure support and neurally adjusted ventilator assist delivered, each, at three levels of ventilatory assistance.
Airways flow and pressure, esophageal pressure, and Eadi were continuously recorded. Sixty tidal volumes for each ventilator settings were analyzed off-line, at three time points during inspiration. For each time point, Pmusc/Eadi index was calculated. Pmusc/Eadi index was also calculated from airway pressure drop during end-expiratory occlusions. Pmusc/Eadi index was very variable among patients, but within one patient it was not affected by type and level of ventilator assistance. Pmusc/Eadi index decreased during the inspiration. Pmusc/Eadi index obtained during an occlusion from airway pressure swing was tightly correlated with that derived from esophageal pressure during tidal ventilation and allowed to estimate pressure time product.
Pmusc is tightly related to Eadi, by a proportionality coefficient that we termed Pmusc/Eadi index, stable within each patient under different conditions of ventilator assistance. The derivation of the Pmusc/Eadi index from Eadi and airway pressure during an expiratory occlusion enables a continuous estimate of patient's inspiratory effort.
Abstract Purpose Prone positioning (PP) improves oxygenation and outcome of patients with acute respiratory distress syndrome undergoing invasive ventilation. We evaluated feasibility and efficacy of ...PP in awake, non-intubated, spontaneously breathing patients with hypoxemic acute respiratory failure (ARF). Material and Methods We retrospectively studied non-intubated subjects with hypoxemic ARF treated with PP from January 2009 to December 2014. Data were extracted from medical records. Arterial blood gas analyses, respiratory rate, and hemodynamics were retrieved 1 to 2 hours before pronation (step PRE), during PP (step PRONE), and 6 to 8 hours after resupination (step POST). Results Fifteen non-intubated ARF patients underwent 43 PP procedures. Nine subjects were immunocompromised. Twelve subjects were discharged from hospital, while 3 died. Only 2 maneuvers were interrupted, owing to patient intolerance. No complications were documented. PP did not alter respiratory rate or hemodynamics. In the subset of procedures during which the same positive end expiratory pressure and F io2 were utilized throughout the pronation cycle (n = 18), PP improved oxygenation (Pa o2 /F io2 124 ± 50 mmHg, 187 ± 72 mmHg, and 140 ± 61 mmHg, during PRE, PRONE, and POST steps, respectively, P < .001), while pH and Pa co2 were unchanged. Conclusions PP was feasible and improved oxygenation in non-intubated, spontaneously breathing patients with ARF.
During acute lung injury (ALI), mechanical ventilation can aggravate inflammation by promoting alveolar distension and cyclic recruitment-derecruitment. As an estimate of the intensity of ...inflammation, metabolic activity can be measured by positron emission tomography imaging of (18)Ffluoro-2-deoxy-D-glucose.
To assess the relationship between gas volume changes induced by tidal ventilation and pulmonary metabolic activity in patients with ALI.
In 13 mechanically ventilated patients with ALI and relatively high positive end-expiratory pressure, we performed a positron emission tomography scan of the chest and three computed tomography scans: at mean airway pressure, end-expiration, and end-inspiration. Metabolic activity was measured from the (18)Ffluoro-2-deoxy-D-glucose uptake rate. The computed tomography scans were used to classify lung regions as derecruited throughout the respiratory cycle, undergoing recruitment-derecruitment, and normally aerated.
Metabolic activity of normally aerated lung was positively correlated both with plateau pressure, showing a pronounced increase above 26 to 27 cm H(2)O, and with regional Vt normalized by end-expiratory lung gas volume. This relationship did not appear to be caused by a higher underlying parenchymal metabolic activity in patients with higher plateau pressure. Regions undergoing cyclic recruitment-derecruitment did not have higher metabolic activity than those collapsed throughout the respiratory cycle.
In patients with ALI managed with relatively high end-expiratory pressure, metabolic activity of aerated regions was associated with both plateau pressure and regional Vt normalized by end-expiratory lung gas volume, whereas no association was found between cyclic recruitment-derecruitment and increased metabolic activity.
Noninvasive ventilation (NIV) is used to treat respiratory failure because it reduces the risks of endotracheal intubation and postextubation respiratory failure. A wide range of different interfaces ...is available, but concerns exist about rebreathing. This study evaluated a total face mask with a 2-limb ventilation circuit and separate access for inflow and outflow gas, which was developed to reduce rebreathing.
In a bench test, a standard total face mask (with a single connector to the ventilation circuit) and the modified total face mask were applied to a mannequin connected to an active breathing simulator. A known CO
flow (V̇
) was delivered to the mannequin's trachea. We tested the following settings: CPAP with the mechanical PEEP valve set at 8 cm H
O (with 60 and 90 L/min continuous flow) and pressure support of 6 and 12 cm H
O (with 2 and 15 L/min bias flow). The settings were tested at simulated breathing frequencies of 15 and 30 breaths/min and with V̇
of 200 and 300 mL/min. The active simulator generated a tidal volume of 500 mL. Airway pressure, air flow, CO
concentration, and CO
flow as the product of air flow and CO
were recorded.
The mean volume of CO
rebreathed and the minimum CO
inspiratory concentration were significantly lower with the modified mask than with the standard mask. The 15 L/min bias flow significantly decreased rebreathing with the DiMax0 mask, whereas it had no effect with the traditional mask.
A face mask with a two-limb ventilation circuit and separate access for inflow and outflow gas reduces rebreathing during NIV. The addition of bias flow enhances this effect. Further studies are required to verify the clinical relevance.
Purpose
Standard polyvinylchloride (PVC) endotracheal tube (ETT) cuffs do not protect from aspiration across the cuff, a leading cause of ventilator-associated pneumonia (VAP). In a long-lasting in ...vitro study we compared the effect of different cuff materials (PVC, polyurethane, and guayule latex), shapes (cylindrical, conical), and positive end expiratory pressures (PEEP) in reducing fluid leakage across the cuff.
Methods
We compared fluid leakage across a cylindrical double-layer guayule latex prototype cuff, three cylindrical PVC cuffs (Mallinckrodt Hi-Lo, Mallinckrodt HighContour, Portex Ivory), one conical PVC cuff (Mallinckrodt TaperGuard), and two polyurethane cuffs (Mallinckrodt SealGuard, conical; Microcuff, cylindrical). Ten centimeters of dyed water was poured above the cuffs inflated (pressure 30 cmH
2
O) in a vertical cylinder (diameter 20 mm). A respiratory circuit connected the bottom of the cylinder to a breathing bag inflated at four pressures (PEEP = 0, 5, 10, 15 cmH
2
O). Pictures were taken every 60 s for 24 h to measure leakage as a reduction in the water column above the cuff. Five new ETTs of each type were tested.
Results
The guayule latex cuffs showed no leakage at all the PEEP levels. Both the cylindrical and conical polyurethane cuffs showed limited leakage (2.1 ± 1.8 cm of water) only for PEEP zero. The PVC cuffs showed reduced leakage with increasing PEEP: 8.4 ± 1.5, 7.8 ± 2.2, 2.2 ± 1.0, and 0 cm of water at 0, 5, 10, and 15 cmH
2
O, respectively. Among all the PVC cuffs, the conical shape ensured higher sealing properties.
Conclusions
The guayule latex cuffs always prevented fluid leakage; the polyurethane and PVC cuffs required incremental levels of PEEP to prevent fluid leakage ever-present at zero PEEP.
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