High-flow nasal cannula oxygen therapy in idiopathic pulmonary fibrosis patients with respiratory failure

Background

High-flow nasal cannula (HFNC) oxygen therapy is widely applied in idiopathic pulmonary fibrosis (IPF) patients with acute respiratory failure (ARF); however, its advantages over mechanical ventilation (MV) remain unclear. We aimed to compare the clinical outcomes of HFNC oxygen therapy and MV in IPF patients with respiratory failure.

Methods

A retrospective descriptive study of patients with IPF admitted between January 2015 and December 2017 who underwent HFNC oxygen therapy or MV during hospitalization was conducted. The primary outcome was the comparison of in-hospital mortality among HFNC only group, MV with prior HFNC group, and MV only group.

Results

A total of 61 patients with IPF and ARF were included in the current study. Forty-five patients received HFNC oxygen therapy without endotracheal intubation and 16 received MV. The overall hospital mortality rate was 59.0%, of which 53.3% was for HFNC oxygen therapy and 55.6% (5/9) for MV only group (P=1.000). Although no significant difference in the mortality rate was observed among three groups, that of MV with prior HFNC oxygen therapy (n=7) was 100% (P=0.064). Additionally, the HFNC oxygen therapy group showed shorter length of hospital and ICU stay than the MV group (P<0.001).

Conclusions

Patients with IPF and ARF who received MV with prior HFNC oxygen therapy showed increased mortality rate than those who received HFNC only oxygen therapy or MV. Considering the complication rate of MV, need for lung transplantation, and the will to undergo end-of-life care, a proper transition from HFNC oxygen therapy to MV should be planned cautiously.

Del-1, an Endogenous Inhibitor of TGF-β Activation, Attenuates Fibrosis

Uncontrolled activation of transforming growth factor (TGF)-β results in a wide range of pathologic conditions. Therapeutic interventions to regulate TGF-β signaling during fibrosis have been developed but the effectiveness is still limited. Here, we show that developmental endothelial locus-1 (Del-1) ameliorates fibrosis in mice by inhibiting α_v integrin-mediated activation of TGF-β. Del-1 bound to α_vβ₆ integrin, an important activator of TGF-β, and inhibited the binding of α_vβ₆ integrin to the latency-associated peptide (LAP), thereby suppressing α_v integrin-mediated activation of TGF-β. Lack of Del-1 increased colocalization of α_v integrin and LAP in the lungs, which was reversed by Del-1 supplementation. The crucial role of Del-1 in regulating TGF-β activity was recapitulated in a mouse model of fibrosis using an adenovirus expressing inactive TGF-β1. Del-1 supplementation improved the pathological characteristics of the mice and reduced mortality. Thus, we propose that Del-1 is a negative regulator of TGF-β activation and a potential anti-fibrotic factor.

A 300-Year High-Resolution Greenland Ice Record of Large-Scale Atmospheric Pollution by Arsenic in the Northern Hemisphere

We report the first high-resolution record of arsenic (As) observed in Greenland snow and ice for the periods 1711-1970 and 2003-2009 AD. The results show well-defined large-scale atmospheric pollution by this toxic element in the northern hemisphere, beginning as early as the 18th century. The most striking feature is an abrupt, unprecedented enrichment factor (EF) peak in the late 1890s, with an ∼30-fold increase in the mean value above the Holocene natural level. Highly enriched As was evident until the late 1910s; a sharp decline was observed after the First World War, reaching a minimum in the early 1930s during the Great Depression. A subsequent increase lasted until the mid-1950s, before decreasing again. Comparisons between the observed variations and Cu smelting data indicate that Cu smelting in Europe and North America was the likely source of early anthropogenic As in Greenland. Despite a significant reduction of ∼80% in concentration and ∼60% in EF from the 1950s to the 2000s, more than 80% of present-day As in Greenland is of anthropogenic origin, probably due to increasing As emissions from coal combustion in China. This highlights the demand for the implementation of national and international environmental regulations to further reduce As emissions.

Clinical outcomes of patients receiving prolonged extracorporeal membrane oxygenation for respiratory support

Background:

There are limited data regarding prolonged extracorporeal membrane oxygenation (ECMO) support, despite increase in ECMO use and duration in patients with respiratory failure. The objective of this study was to investigate the outcomes of severe acute respiratory failure patients supported with prolonged ECMO for more than 28 days.

Methods:

Between January 2012 and December 2015, all consecutive adult patients with severe acute respiratory failure who underwent ECMO for respiratory support at 16 tertiary or university-affiliated hospitals in South Korea were enrolled retrospectively. The patients were divided into two groups: short-term group defined as ECMO for ⩽28 days and long-term group defined as ECMO for more than 28 days. In-hospital and 6-month mortalities were compared between the two groups.

Results:

A total of 487 patients received ECMO support for acute respiratory failure during the study period, and the median support duration was 8 days (4–20 days). Of these patients, 411 (84.4%) received ECMO support for ⩽28 days (short-term group), and 76 (15.6%) received support for more than 28 days (long-term group). The proportion of acute exacerbation of interstitial lung disease as a cause of respiratory failure was higher in the long-term group than in the short-term group (22.4% versus 7.5%, p < 0.001), and the duration of mechanical ventilation before ECMO was longer (4 days versus 1 day, p < 0.001). The hospital mortality rate (60.8% versus 69.7%, p = 0.141) and the 6-month mortality rate (66.2% versus 74.0%, p = 0.196) were not different between the two groups. ECMO support longer than 28 days was not associated with hospital mortality in univariable and multivariable analyses.

Conclusions:

Short- and long-term survival rates among patients receiving ECMO support for more than 28 days for severe acute respiratory failure were not worse than those among patients receiving ECMO for 28 days or less.

The effect of human adipose-derived stem cells on lipopolysaccharide-induced acute respiratory distress syndrome in mice

Background

Acute respiratory distress syndrome (ARDS) is a type of acute respiratory failure in critically ill patients. Recently, several treatment modalities have been proposed for ARDS, but it still has a high mortality rate. In general, the role of mesenchymal stem cells (MSCs) in controlling inflammatory responses has been studied in various immune-associated diseases in humans and animals. However, only a few studies reported adipose-derived stem cells (ASCs), which are easier to isolate, are currently emerging as an attractive treatment option in ARDS. Therefore, in this study, we investigated the therapeutic effects of human ASCs and the regulation of inflammatory responses in an ARDS mouse model.

Methods

In the ARDS model, lipopolysaccharide (LPS) (5 mg/kg) was administered via the intra tracheal injection method. The mice were divided into the following four groups: (I) saline + medium; (II) saline + ASCs (2×10⁵); (III) LPS + medium; (IV) LPS + ASCs. The ARDS observation time was divided into short and long term. LPS administration increased the concentration of proinflammatory cytokines, which was a consistent systemic inflammatory response.

Results

LPS/ASC group showed less neutrophil infiltration and less alveolar hemorrhage or congestion than did the LPS group. The lung injury scores of the LPS/ASC group were lower than those of the LPS group (3.8±0.9 vs. 6.8±1.1; P=0.03) at day 2. Compared to the LPS group, LPS/ASC group showed reduced collagen deposition around the vessels and fibrosis accompanied by alveolar septal or interstitial thickening and lower MPO levels than did the LPS group (453.2±26.2 vs. 670.2±65.9 pg/mL; P<0.01) at day 7.

Conclusions

ASC therapy can inhibit neutrophil recruitment, which shows trend of reducing short term lung injury (day 2) and affecting fibrosis in long term (day 7). Further studies are warranted to understand the mechanism and improve the therapeutic effect of ASCs.

Improved survival rates in patients with H1N1 acute respiratory failure in Korea between 2009 and 2016

There was a pandemic of influenza A (H1N1) in 2009; in Korea, there was also an H1N1 epidemic in 2016. We aim to investigate whether survival had improved in the setting of recent advances in intensive care unit (ICU) management. We conducted a retrospective analysis of acute respiratory failure patients with H1N1 influenza pneumonia in 2016 and 2009 respectively at two tertiary referral hospitals in Korea. A total of 28 patients were treated in 2016, and 34 in 2009. There was no significant difference in SOFA scores on ICU admission day. In-hospital mortality was significantly lower in patients of 2016 compared to those of 2009 (18% vs. 44% P = 0.028). By multivariable analyses, the treatment year 2016 was associated with a greater likelihood of survival. Compared to the patients treated in 2009, those treated in 2016 were one seventh as likely to die after adjusting for other clinical variables (hazard ratio for mortality, 0.15; 95% confidence interval. 0.03–0.63, P = 0.010). Improved survival in patients who underwent extracorporeal membrane oxygenation treatment (in-hospital mortality, 17% vs. 60%, P = 0.242) and decreased tidal volumes during mechanical ventilation (median 5.4 mL/kg vs. median 9.2 mL/kg, P = 0.018) were observed in 2016 compared to 2009. Treatment outcomes for patients with H1N1 acute respiratory failure improved from 2009 to 2016 in two tertiary referral centers in South Korea.

Risk factors of severe hemoptysis in patients with fungus ball

Background

Hemoptysis is one of the most important complications associated with fungus ball. However, the association of the primary size of the fungus ball and its change with the incidence of hemoptysis was not fully established. This study aims to determine the clinical risk factors of severe hemoptysis and natural course of fungus ball.

Methods

A retrospective study on patients with fungus ball was performed. Patients with severe hemoptysis-related events were compared to those without events, and the predictors for severe hemoptysis were investigated by Cox regression analysis. Three subgroups (decreased, stable, and increased) were classified according to the long-term size change, and the severe hemoptysis-free survival duration was analyzed by the Kaplan-Meier survival curve.

Results

Among 173 patients, 50 (28.9%) experienced severe hemoptysis-related events. Risk-adjusted analysis revealed that age [hazard ratio (HR), 0.964; 95% confidence interval (CI), 0.939-0.989], blood-tinged sputum [HR, 2.717; 95% CI, 1.513-4.879], and thick wall cavitary fungus balls [HR, 2.332; 95% CI, 1.290-4.215] were significant predictors of severe hemoptysis-related events in patients with fungus ball. However, the baseline size of the fungus ball and its change rate were not independent risk factors for severe hemoptysis-related events. Besides, the decreased group did not have a favorable outcome in severe hemoptysis related to fungus ball.

Conclusions

In a tertiary hospital, the incidence of severe hemoptysis-related events in patients with fungus ball was not low and reached 28.9%. Young patients, those with thick wall cavitary fungus ball, and those with complaints of blood-tinged sputum should be considered for early surgical treatment to prevent severe hemoptysis.

Serum developmental endothelial locus-1 is associated with severity of sepsis in animals and humans

Disruption of the endothelial glycocalyx has a prominent role in the pathophysiology of sepsis. Developmental endothelial locus-1 (Del-1) is an endothelial-derived anti-inflammatory factor. We hypothesized that degradation of the endothelial glycocalyx during sepsis may increase serum Del-1. A mouse model of sepsis was created using cecal ligation and puncture. In septic mice, the endothelial glycocalyx was nearly completely degraded, with less formation of Del-1 in the endothelium and extracellular matrix than in control mice. Serum Del-1 levels were significantly increased in the septic mice with increasing severity of sepsis. Serum Del-1 levels were also measured in 84 patients with sepsis and septic shock and in 20 control subjects. The median serum Del-1 level in patients with sepsis was significantly higher than that in healthy controls. The high Del-1 group had higher illness severity scores and contained more patients with organ dysfunction than the low Del-1 group. The 90-day mortality rate was significantly higher in the high Del-1 group than in the low Del-1 group. Multivariate analysis indicated a tendency for a high serum Del-1 level to be associated with a higher mortality risk. Increased serum Del-1 may be a novel diagnostic biomarker of sepsis and an indicator of disease severity.

Humidifier disinfectant and use characteristics associated with lung injury in Korea

Since around the year 2000, hundreds of people in Korea have developed humidifier disinfectant-associated lung injury (HDLI). We collected all HD exposure-related information from the field investigations into the locations in which the 1199 registered patients had used HD. Among the people who registered, 38% (1st round = 214, 2nd = 73, 3rd = 166) were confirmed as HDLI patients. Children aged under eight years old made up the highest proportion of HDLI cases (N = 279, 62%), followed by pregnant women (N = 31, 7%). One hundred thirty-three (29%) of the confirmed HDLI patients died. Fifty-seven percent of HDLI patients (N = 259) developed HDLI after <1 year of HD use. The number of HDLI patients who used only the Oxy Saksak HD brand was found to be 176 (39%), followed by the brands Cefu (N = 27, 6%) and Aekyung (N = 22, 5%). HD products containing only polyhexamethylene guanidine phosphate (PHMG-P) were the most frequently used among HDLI patients (N = 234, 52%), followed by oligo (2-(2-ethoxy)ethoxyethyl) guanidinium (PGH) (N = 27, 6%) and a mixture of chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) (N = 26, 6%). The average PHMG-P inhalation level estimated from the patient group classified as suffering lung injury definitely associated with HD use was 145.1 μg/m³ (N = 91, SD = 395.1 μg/m³ ), higher than levels estimated from both the probable and possible HDLI patient groups. In conclusion, HD exposure-related variables, including type of HD brand and estimated inhalation HD level, were associated with the risk of HDLI.

Effect of adjunctive corticosteroid on 28-day mortality in neutropenic patients with septic shock

The role of adjunctive corticosteroid in septic shock remains debatable, and its role has not been assessed in neutropenic patients. We evaluated whether hydrocortisone reduces 28-day mortality in neutropenic patients with septic shock. We conducted a retrospective cohort study between January 2012 and May 2017 at a tertiary care center in South Korea. Patients who developed septic shock treated with at least one vasopressor and whose absolute neutrophil count was < 1000 cells/μL were included. Patients were classified into a steroid and a no-steroid group. The primary outcome of the study was 28-day mortality. Propensity score matching was used to adjust baseline characteristics and disease severity between the groups. Of the 287 patients analyzed, 189 were classified in the no-steroid group and 98 in the steroid group. Fifty propensity score-matched pairs were compared for the study outcomes. We found no significant difference in 28-day mortality between patients treated with and without steroid after propensity score matching (38.0% and 42.0%, respectively; p = 0.838). Incidences of pneumonia and gastrointestinal bleeding were more frequent in the steroid group, but it was not statistically significant after matching. In conclusion, adjunctive hydrocortisone was not associated with reduced 28-day mortality in neutropenic patients with septic shock.

Preoperative N stage evaluation in advanced gastric cancer patients using multidetector CT: can the sum of the diameters of metastatic LNs be used for N stage evaluation?

AIM

To compare the diagnostic performance of total counts of metastatic lymph nodes (LN-sum) and conventional multidetector (MD) computed tomography (CT) staging in the nodal evaluation of advanced gastric cancer (AGC) patients.

MATERIALS AND METHODS

In total, 127 consecutive patients who underwent preoperative MDCT and gastrectomy for AGC were identified. Metastatic LNs on MDCT were defined as LNs with a short axis ≥8 mm, marked or heterogeneous enhancement, and morphological features (central necrosis, round shape, clustering). The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of the N-stage using LN-sum and conventional MDCT staging were generated and compared. In addition, metastatic LN counts between the MDCT and the histopathological examinations and correlation between LN-sum and histopathological nodal status were analysed.

RESULTS

The total counts of metastatic LNs on MDCT was significantly smaller than those detected in histopathological assessments (p<0.0001). LN-sum showed significant correlation with the pathological N stage and the number of metastatic LNs (rho=0.69, 0.73, p<0.0001). The areas under the receiver operating characteristic curve were 0.896, and 0.835, for N stage ≥N2 and N3, with cut-off values of 12.5 and 23.5 mm, respectively. LN-sum provided better diagnostic performance than conventional MDCT staging for discriminating N0-2 versus N3; sensitivity, accuracy, PPV and NPV of LN-sum were significantly higher (80.4 versus 52.2%, 81.1 versus 68.5%, 71.2 versus 57.1%, and 88 versus 74.1%).

CONCLUSION

LN-sum may be sufficiently useful in assessing the N3 stage of AGC and may help to plan appropriate therapy for AGC patients.

The Role of Exosomes in Bronchoalveloar Lavage from Patients with Acute Respiratory Distress Syndrome

Background: Acute respiratory distress syndrome (ARDS) is a life-threatening condition caused by pulmonary and extrapulmonary insults. Exosomes are considered a major cell-to-cell communicator and immune modulator. However, their role in ARDS remains unclear. In this study, we investigated whether exosomes could be a potential biomarker of ARDS. Methods: We isolated exosomes from bronchoalveolar lavage (BAL) of patients with ARDS. The correlation between the level of exosomes with clinical data, including etiology, oxygenation, and 28-day mortality was analyzed. Enzyme-linked immune sorbent assays and western blotting were carried out to characterize BAL exosomes. Immune modulating response of exosomes was investigated by in vitro examination. Results: From 158 patients, we isolated mean 1568.9 µg/mL BAL exosomes, which presented a negative correlation with the PaO₂/FiO₂ ratio. The level of exosomes did not correlate with 28-day mortality but was elevated in the infectious etiology of ARDS. The exosomes have cargo proteins associated with apoptosis, necroptosis, and autophagy. An in vitro stimulation study revealed that BAL exosomes could induce the production of proinflammatory cytokines and chemokines, but those from patients with ARDS suppressed the production of vascular endothelial growth factor. Conclusions: In ARDS, exosomes are released in alveolar space, and the level is correlated with the etiology of ARDS. BAL exosomes could play an immune-modulating role by controlling the production of cytokines.

Use of extracorporeal membrane oxygenation in patients with acute high-risk pulmonary embolism: a case series with literature review

Background

Although extracorporeal membrane oxygenation (ECMO) has been used for the treatment of acute high-risk pulmonary embolism (PE), there are limited reports which focus on this approach. Herein, we described our experience with ECMO in patients with acute high-risk PE.

Methods

We retrospectively reviewed medical records of patients diagnosed with acute high-risk PE and treated with ECMO between January 2014 and December 2018.

Results

Among 16 patients included, median age was 51 years (interquartile range [IQR], 38 to 71 years) and six (37.5%) were male. Cardiac arrest was occurred in 12 (75.0%) including two cases of out-of-hospital arrest. All patients underwent veno-arterial ECMO and median ECMO duration was 1.5 days (IQR, 0.0 to 4.5 days). Systemic thrombolysis and surgical embolectomy were performed in seven (43.8%) and nine (56.3%) patients, respectively including three patients (18.8%) received both treatments. Overall 30-day mortality rate was 43.8% (95% confidence interval, 23.1% to 66.8%) and 30-day mortality rates according to the treatment groups were ECMO alone (33.3%, n=3), ECMO with thrombolysis (50.0%, n=4) and ECMO with embolectomy (44.4%, n=9).

Conclusions

Despite the vigorous treatment efforts, patients with acute high-risk PE were related to substantial morbidity and mortality. We report our experience of ECMO as rescue therapy for refractory shock or cardiac arrest in patients with PE.

Association Between Time to Defibrillation and Neurologic Outcome in Patients With In-Hospital Cardiac Arrest

BACKGROUND

The influence of time to defibrillation in patients with shockable in-hospital cardiac arrest (IHCA) has not been fully assessed. This study investigated the association between time to defibrillation and neurologic outcome in shockable IHCA survivors.

MATERIALS AND METHODS

A 7-year retrospective cohort study was conducted using a prospectively collected registry of adult IHCA patients. Patients whose first documented rhythm was pulseless ventricular tachycardia or ventricular fibrillation and who received defibrillation within 5 minutes were included.

RESULTS

Among 1,683 IHCA patients, 261 patients were included. At 28 days, a good neurologic outcome (Cerebral Performance Category score 1 or 2) according to time to defibrillation was seen in 49.0%, 21.1%, 13.4% and 16.5% of patients treated at <2 minutes (n = 128), 2-3 minutes (n = 55), 3-4 minutes (n = 35) and 4-5 minutes (n = 43) after IHCA, respectively. After adjusting for clinical characteristics, a graded inverse association was found after 3 minutes.

CONCLUSIONS

A graded inverse association between time to defibrillation and neurologic outcome was observed beyond 3 minutes following cardiac arrest. A target time to defibrillation of <3 minutes may be a practical target goal in resource-limited hospitals.

Medical resource utilization patterns and mortality rates according to age among critically ill patients admitted to a medical intensive care unit

There is ongoing controversy about how to address the growing demand for intensive care for critically ill elderly patients. We investigated resource utilization patterns and mortality rates according to age among critically ill patients.We retrospectively analyzed the medical records of patients admitted to a medical intensive care unit (ICU) in a tertiary referral teaching hospital between July 2006 and June 2015. Patients were categorized into non-elderly (age <65 years, n = 4140), young-elderly (age 65-74 years, n = 2306), and old-elderly (age ≥75 years, n = 1508) groups.Among 7954 admissions, the mean age was 61.5 years, and 5061 (63.6%) were of male patients. The proportion of comorbidities increased with age (64.6% in the non-elderly vs 81.4% in the young-elderly vs 82.8% in the old-elderly, P < .001 and P for trend <.001), whereas the baseline Sequential Organ Failure Assessment (SOFA) score decreased with age (8.1 in the non-elderly vs 7.2 in the young-elderly vs 7.2 in the old-elderly, P < .001, R = -.092 and P for trend <.001). Utilization rates of mechanical ventilation (48.6% in the non-elderly vs 48.3% in the young-elderly vs 45.5% in the old-elderly, P = .11) and renal replacement therapy (27.5% in the non-elderly vs 25.5% in the young-elderly vs 24.8% in the old-elderly, P = .069) were comparable between the age groups. The 28-day ICU mortality rates were lower in the young-elderly and the old-elderly groups than in the non-elderly group (35.6% in the non-elderly vs 34.2% in the young-elderly, P = .011; and vs 32.6% in the old-elderly, P = .002).A substantial number of critically ill elderly patients used medical resources as non-elderly patients and showed favorable clinical outcomes. Our results support that underlying medical conditions rather than age per se need to be considered for determining intensive care.

Rapid response systems in Korea

The inpatient treatment process is becoming more and more complicated with advanced treatments, aging of the patient population, and multiple comorbidities. During the process, patients often experience unexpected deterioration, about half of which might be preventable. Early identification of patient deterioration and the proper response are priorities in most healthcare facilities. A rapid response system (RRS) is a safety net to identify antecedents of these adverse events and to respond in a timely manner. The RRS has become an essential part of the medical system worldwide, supported by all major quality improvement organizations. An RRS consists of a trigger system and response team and needs constant assessment and process improvement. Although the effectiveness and cost-benefit of RRS remain controversial, according to previous studies, it may be beneficial by decreasing in-hospital cardiac arrest and mortality. Since the first implementation of RRS in Korea in 2008, it has been developed in over 15 medical centers and continues to expand. Recent accreditation standards and an RRS pilot program by the Korean government will promote the proliferation of RRSs in Korea.

Right ventricular assist device with an oxygenator using extracorporeal membrane oxygenation as a bridge to lung transplantation in a patient with severe respiratory failure and right heart decompensation

Right heart decompensation is a fatal complication in patients with respiratory failure, particularly in those transitioned to lung transplantation using veno-venous extracorporeal membrane oxygenation (V-V ECMO). In these patients, veno-arterial (V-A ECMO) or veno-arterialvenous extracorporeal membrane oxygenation (V-AV ECMO) is used to support both cardiac and respiratory function. However, these processes may increase the risk of device-related complications such as bleeding, thromboembolism, and limb ischemia. In the present case, a 64-year-old male patient with idiopathic pulmonary fibrosis developed respiratory failure and commenced treatment with V-V ECMO as a bridge to lung transplantation. Unfortunately, the patient developed right heart decompensation and required both cardiac and respiratory support during treatment with V-V ECMO. Instead of adding arterial cannulation, he was switched to a novel configuration, a right ventricular assist device with an oxygenator (Oxy- RVAD) using ECMO, with drainage cannulation from the femoral vein and return cannulation to the main pulmonary artery. The patient was successfully bridged to lung transplantation without serious complications after 10 days of Oxy-RVAD support. To the best of our knowledge, this is an extreme rare and challenging case of Oxy-RVAD using ECMO in a patient successfully bridged to lung transplantation.

Vitamin C alone does not improve treatment outcomes in mechanically ventilated patients with severe sepsis or septic shock: a retrospective cohort study

Background

Vitamin C has shown several beneficial effects on sepsis in preclinical studies. However, clinical data supporting these reports are scarce. This study aimed to evaluate whether adjunctive intravenous vitamin C therapy could reduce hospital mortality in patients with severe sepsis or septic shock requiring mechanical ventilation.

Methods

For this retrospective cohort study, consecutive medical ICU patients with severe sepsis or septic shock requiring mechanical ventilation were included. The study patients were classified into the vitamin C or control groups depending on the administration of intravenous vitamin C (2 g every 8 hours). The primary outcome was hospital mortality.

Results

Thirty-five patients in the vitamin C group and 40 patients in the control group were included. The two groups were comparable in regards to the baseline characteristics at ICU admission. The hospital mortality was 46% (16 of 35 patients) in the vitamin C group and 40% (16 of 40 patients) in the control group, showing a statistically nonsignificant difference (P=0.62). The mortality at 90 days after ICU admission (60% vs. 48%) did not significantly differ between groups. The median time to shock reversal was 3 days [interquartile range (IQR), 2 to 5 days] in both groups. The changes in the Sepsis-related Organ Failure Assessment (SOFA) scores during the first 4 ICU days were -1.4±3.3 and -1.4±3.0 in the vitamin C and control groups, respectively.

Conclusions

Adjunctive intravenous vitamin C therapy alone did not reduce hospital mortality in mechanically ventilated patients with severe sepsis or septic shock.

Lung Compliance and Outcomes in Patients With Acute Respiratory Distress Syndrome Receiving ECMO

BACKGROUND

Limited data are available regarding mechanical ventilation strategies in patients with acute respiratory distress syndrome receiving extracorporeal membrane oxygenation (ECMO).

METHODS

A retrospective analysis of acute respiratory distress syndrome patients on ECMO was conducted in 9 hospitals in Korea. Data on ventilator settings (pre-ECMO and 0, 4, 24, and 48 hours after ECMO) were collected. Based on the effect of the duration and intensity of mechanical ventilator on outcomes, time-weighted average values were calculated for ventilator parameters.

RESULTS

The 56 patients included in the study had a mean age of 55.5 years. The hospital and 6-month mortality rates were 48.1% and 54.0%, respectively, with a median ECMO duration of 9.4 days. After initiation of ECMO, peak inspiratory pressure, above positive end-expiratory pressure, tidal volume, and respiration rate were reduced, while lung compliance did not change significantly. Before and during ECMO support, tidal volume and lung compliance were higher in 6-month survivors than in nonsurvivors. In Cox proportional models, both lung compliance (odds ratio, 0.961; 95% confidence interval, 0.928 to 0.995) and time-weighted average-lung compliance (odds ratio, 0.943; 95% confidence interval, 0.903 to 0.986) were significantly associated with 6-month mortality. Kaplan-Meier curves revealed that patients with higher lung compliance before ECMO had a longer survival time at the 6-month follow-up than did those with lower lung compliance.

CONCLUSIONS

Lung compliance, whether before or during ECMO, may be an important predictor of outcome in acute respiratory distress syndrome patients receiving ECMO. However, this result requires confirmation in larger clinical studies.

The natural history of non-cavitary nodular bronchiectatic Mycobacterium avium complex lung disease

PURPOSE

We aimed to investigate the natural history of non-cavitary nodular bronchiectatic (NC-NB) Mycobacterium avium complex (MAC) lung disease (LD).

METHODS

Among all patients diagnosed with NC-NB MAC LD between March 2000 and December 2013, 551 patients who were followed until December 2017 were enrolled at a tertiary referral center in South Korea. Patients were subdivided into progressive and stationary groups, depending on whether treatment was initiated within 3 years after diagnosis. We investigated the proportion of patients not receiving anti-MAC treatment within 3 years after the diagnosis. The rate for spontaneous sputum conversion in the untreated group was also calculated.

RESULTS

The mean age of 551 patients was 61.1 years. During the median 5.8 years of follow-up, 323 (58.6%) patients received treatment within 3 years (progressive group), whereas the remaining 228 (41.4%) patients did not (stationary group). Multivariate analysis revealed that age ≤ 60 years, a positive sputum smear, the presence of systemic symptoms, body mass index >18.5 kg/m², and the involvement of ≥ 4 lobes were predictors of receiving treatment. Additionally, during the median of 5.0 years follow-up, spontaneous sputum conversion occurred in 52.2% of patients who did not receive treatment.

CONCLUSIONS

Among patients diagnosed with NC-NB MAC LD, approximately 40% did not receive antibiotic treatment within 3 years of diagnosis. Moreover, about 50% of untreated patients experienced spontaneous sputum conversion.