A novel measure to summarize blood transfusion practice during critical illness

BACKGROUND

Large-scale observational studies have summarized transfusion practice using traditional measures of central tendency (e.g., the mean hemoglobin concentration at the time of transfusion). However, the mean hemoglobin concentration fails to identify specific hemoglobin concentration thresholds that drive practice. In the following brief report, we propose a novel measure of "practice discontinuity" that identifies specific practice-defining hemoglobin thresholds.

STUDY DESIGN AND METHODS

We used the PINC AI Database (2016-2022) to identify adult patients admitted to an intensive care unit with at least one hemoglobin concentration measurement. For each day that hemoglobin was measured, we identified whether the patient received a red blood cell transfusion using hospital charge codes. We defined the "practice discontinuity" measure as the hemoglobin concentration at which there was the largest increase in transfusion use going from a higher to an incrementally lower hemoglobin concentration. We also calculated the mean and median pretransfusion hemoglobin concentrations.

RESULTS

We identified 1,298,367 patients and 4,905,839 patient-days for inclusion. RBC transfusion occurred in a total of 530,654 (10.8%) patient-days. The overall pre-transfusion mean and median hemoglobin concentrations were 8.4 and 8.0 g/dL, respectively. The practice discontinuity measure identified 7.0 g/dL as the hemoglobin concentration at which transfusion use increased the most, from 46.6% of patient-days at a concentration of 7.0 g/dL to 74.8% of patient-days at a concentration of 6.9 g/dL.

DISCUSSION

We propose that future studies of red blood cell transfusion practice consider inclusion of the practice discontinuity measure to more fully summarize clinical practice.

Variation in Use of Medications for Opioid Use Disorder in Critically Ill Patients Across the United States

OBJECTIVES

To describe practice patterns surrounding the use of medications to treat opioid use disorder (MOUD) in critically ill patients.

DESIGN

Retrospective, multicenter, observational study using the Premier AI Healthcare Database.

SETTING

The study was conducted in U.S. ICUs.

PATIENTS

Adult (≥ 18 yr old) patients with a history of opioid use disorder (OUD) admitted to an ICU between 2016 and 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 108,189 ICU patients (658 hospitals) with a history of OUD, 20,508 patients (19.0%) received MOUD. Of patients receiving MOUD, 13,745 (67.0%) received methadone, 2,950 (14.4%) received buprenorphine, and 4,227 (20.6%) received buprenorphine/naloxone. MOUD use occurred in 37.9% of patients who received invasive mechanical ventilation. The median day of MOUD initiation was hospital day 2 (interquartile range [IQR] 1-3) and the median duration of MOUD use was 4 days (IQR 2-8). MOUD use per hospital was highly variable (median 16.0%; IQR 10-24; range, 0-70.0%); admitting hospital explained 8.9% of variation in MOUD use. A primary admitting diagnosis of unintentional poisoning (aOR 0.41; 95% CI, 0.38-0.45), presence of an additional substance use disorder (aOR 0.66; 95% CI, 0.64-0.68), and factors indicating greater severity of illness were associated with reduced odds of receiving MOUD in the ICU.

CONCLUSIONS

In a large multicenter, retrospective study, there was large variation in the use of MOUD among ICU patients with a history of OUD. These results inform future studies seeking to optimize the approach to MOUD use during critical illness.

Practice Patterns and Outcomes of Potassium Repletion Thresholds during Critical Illness

Rationale: Potassium repletion is common in critically ill patients. However, practice patterns and outcomes related to different intensive care unit (ICU) potassium repletion strategies are unclear. Objectives: 1) Describe potassium repletion practices in critically ill adults; 2) compare the effectiveness of potassium repletion strategies; and 3) compare effectiveness and safety of specific potassium repletion thresholds on patient outcomes. Methods: This was a retrospective analysis of the PINC AI Healthcare Database (2016-2022), including all critically ill adults admitted to an ICU on Hospital Day 1 and with a serum potassium concentration measured on Hospital Day 2. We determined the frequency of potassium repletion (any formulation) at each measured serum potassium concentration in each ICU, then classified ICUs as having threshold-based (a large increase in potassium repletion rates at a specific serum potassium concentration) or probabilistic (linear relationship between serum concentration and the repletion probability) patterns of repletion. Between patients in threshold-based and probabilistic repletion ICUs, we compared outcomes (primary outcome: potassium repletion frequency). We reported unadjusted percentages per exposure group and the adjusted odds ratios (from hierarchical regression models) for each outcome. Among patients in threshold-based ICUs with the most common repletion thresholds (3.5 mEq/L and 4.0 mEq/L), we conducted regression discontinuity analyses to examine the effectiveness of potassium repletion at each potassium threshold. Results: We included 190,490 patients in 88 ICUs; 35.0% received at least one dose of potassium on the same calendar day. Rates of potassium repletion were similar between 22 threshold-based strategy ICUs (33.5%) and 22 probabilistic strategy ICUs (36.4%). There was no difference in the adjusted risk of potassium repletion between patients admitted to threshold-based strategy ICUs versus probabilistic strategy ICUs (adjusted odds ratio, 1.09; 95% confidence interval [CI], 0.76-1.57). In regression discontinuity analysis, crossing the 3.5 mEq/L threshold from high to low potassium levels resulted in a 39.1% (95% CI, 23.7-42.4) absolute increase in potassium repletion but no change in other outcomes. Similarly, crossing the 4.0 mEq/L threshold resulted in a 36.4% (95% CI, 22.4-42.2) absolute increase in potassium repletion but no change in other outcomes. Conclusions: Potassium repletion is common in critically ill patients and occurs over a narrow range of "normal" potassium levels (3.5-4.0 mEq/L); use of a threshold-based repletion strategy to guide potassium repletion in ICU patients is not associated with clinically meaningful differences in outcomes.

Variation in Sedative and Analgesic Use During the COVID-19 Pandemic and Associated Outcomes

BACKGROUND

Providing analgesia and sedation is an essential component of caring for many mechanically ventilated patients. The selection of analgesic and sedative medications during the COVID-19 pandemic, and the impact of these sedation practices on patient outcomes, remain incompletely characterized.

RESEARCH QUESTION

What were the hospital patterns of analgesic and sedative use for patients with COVID-19 who received mechanical ventilation (MV), and what differences in clinical patient outcomes were observed across prevailing sedation practices?

STUDY DESIGN AND METHODS

We conducted an observational cohort study of hospitalized adults who received MV for COVID-19 from February 2020 through April 2021 within the Society of Critical Care Medicine Discovery Viral Infection and Respiratory Illness Universal Study (VIRUS) COVID-19 Registry. To describe common sedation practices, we used hierarchical clustering to group hospitals based on the percentage of patients who received various analgesic and sedative medications. We then used multivariable regression models to evaluate the association between hospital analgesia and sedation cluster and duration of MV (with a placement of death [POD] approach to account for competing risks).

RESULTS

We identified 1,313 adults across 35 hospitals admitted with COVID-19 who received MV. Two clusters of analgesia and sedation practices were identified. Cluster 1 hospitals generally administered opioids and propofol with occasional use of additional sedatives (eg, benzodiazepines, alpha-agonists, and ketamine); cluster 2 hospitals predominantly used opioids and benzodiazepines without other sedatives. As compared with patients in cluster 2, patients admitted to cluster 1 hospitals underwent a shorter adjusted median duration of MV with POD (β-estimate, -5.9; 95% CI, -11.2 to -0.6; P = .03).

INTERPRETATION

Patients who received MV for COVID-19 in hospitals that prioritized opioids and propofol for analgesia and sedation experienced shorter adjusted median duration of MV with POD as compared with patients who received MV in hospitals that primarily used opioids and benzodiazepines.

Effectiveness of Fludrocortisone Plus Hydrocortisone Versus Hydrocortisone Alone in Septic Shock: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

RATIONALE

The use of hydrocortisone in adult septic shock is controversial, and effectiveness of adding fludrocortisone to hydrocortisone remains uncertain.

OBJECTIVE

To assess comparative effectiveness and safety of fludrocortisone plus hydrocortisone, hydrocortisone alone and placebo/usual care in adults with septic shock.

METHODS

Systematic review and Bayesian network meta-analysis of peer-reviewed randomized trials. The primary outcome was all-cause mortality at last follow-up. Treatment effects were presented as relative risks (RR) with 95% credible intervals (CrI). Placebo/usual care was the reference treatment.

MAIN RESULTS

Out of 7,553 references, we included 17 trials (7,688 patients). All-cause mortality at last follow-up was lowest with fludrocortisone plus hydrocortisone (RR: 0.85, 95% CrI: 0.72-0.99, 98.3% probability of superiority, moderate-certainty evidence), followed by hydrocortisone alone (RR: 0.97, 95% CrI: 0.87-1.07, 73.1% probability of superiority, low-certainty evidence). The comparison of fludrocortisone plus hydrocortisone versus hydrocortisone alone was primarily based on indirect evidence (only two trials with direct evidence). Fludrocortisone plus hydrocortisone was associated with a 12% lower risk of all-cause mortality compared to hydrocortisone alone (RR: 0.88, 95% CrI: 0.74-1.03, 94.2% probability of superiority, moderate-certainty evidence).

CONCLUSIONS

In adult septic shock patients, fludrocortisone plus hydrocortisone was associated with lower risk of all-cause mortality at last follow-up than placebo and hydrocortisone alone. The scarcity of head-to-head trials comparing fludrocortisone plus hydrocortisone versus hydrocortisone alone led our network meta-analysis to rely primarily on indirect evidence for this comparison. Though we undertook several sensitivity analyses and assessments, these findings should be considered while also acknowledging the heterogeneity of included trials.

Comparative Effectiveness of Mepolizumab, Benralizumab and Dupilumab among Patients with Difficult-to-Control Asthma

Rationale The comparative effectiveness of biologics used as add-on therapy in the management of difficult-to-control asthma is unclear. Objective To compare the effectiveness of dupilumab, mepolizumab and benralizumab among patients with difficult-to-control asthma. Methods Retrospective multicenter cohort study of adult patients with difficult-to-control asthma started on dupilumab, mepolizumab or benralizumab from a multicenter electronic health record and claims-based database between October 19, 2018 and September 30, 2022. Propensity score matching was used to minimize bias from non-randomized treatment assignment; prespecified alpha level was set at 0.017 to account for three primary comparisons. The exposure of interest was new initiation of dupilumab, benralizumab or mepolizumab. The primary outcome was the rate of asthma exacerbation in the year following initiation of biologic therapy modeled using a negative binomial approach. Results Among 893,668 patients with asthma who were prescribed an inhaled corticosteroid and were at least 12 years old, (65% female, mean age 49), 3,943 started dupilumab, 1,902 started benralizumab, and 2,012 started mepolizumab without an alternative indication for biologic therapy. After matching, there were 1,805 patients in each group for comparisons between dupilumab and benralizumab, 1,865 for comparisons between dupilumab and mepolizumab, and 1,721 for comparisons between mepolizumab and benralizumab. For all pairwise comparisons, covariates were well balanced after matching (all standardized mean differences <0.1). Patients initiating dupilumab had a significantly lower rate of asthma exacerbations (1.07/year) compared to benralizumab (1.47/year) with a rate ratio of 0.73 [95% confidence interval (CI) 0.63-0.85] and also had a significantly lower rate of asthma exacerbations compared to mepolizumab (1.04/year compared to 1.45/year) with a rate ratio of 0.72 [0.62-0.84]. There was no statistically significant difference in the rate of asthma exacerbations between mepolizumab (1.40/year) and benralizumab (1.41/year) with a rate ratio of 1.00 [CI 0.85-1.17]. Conclusions In patients with difficult-to-control asthma newly initiated on biologic therapy, dupilumab was associated with a decreased rate of asthma exacerbations in the year after initiation as compared with mepolizumab or benralizumab.

Effect of Respiratory Viral Panel Adoption on Antibiotic Use in Ventilated Patients

Rationale: Rapid respiratory viral panel (RVP) testing has become widely used to aid in the diagnosis and treatment of acute respiratory failure. However, the impact of RVP on antibiotic stewardship in critically ill patients is unclear. Objectives: To assess if adoption of RVP testing at hospitals was associated with changes in antibiotic duration in intensive care unit patients receiving invasive mechanical ventilation. Methods: With data from the Premier Inc. database from 2016 to 2019, we used interrupted time series with multivariable hierarchical linear regression models to quantify trends in outcomes for 31,644 patients in the 12 months before RVP adoption, the level change in outcomes at the time of RVP adoption (estimand of interest), and changes in outcome trends in the 12 months after RVP adoption. Results: Hospital adoption of RVP testing (n = 62,603) was associated with a decrease in days of antibiotics by 0.5 days (95% confidence interval, -0.8, -0.1) in the first month after adoption. There was also a significant decrease in the risk of Clostridioides difficile infection by 0.9% (95% confidence interval, -1.6, -0.3). There were no significant changes in other outcomes, including hospitalization costs, hospital length of stay, or rates of ventilator-associated pneumonia. Conclusions: Hospital adoption of RVP testing was associated with modest reductions in both antibiotic duration and risk of C. difficile infection among intensive care unit patients with acute respiratory failure and suspected infection.

Patient Outcomes After Long-Term Acute Care Hospital Closures

Importance

Long-term acute care hospitals (LTCHs) are common sites of postacute care for patients recovering from severe respiratory failure requiring mechanical ventilation (MV). However, federal payment reform led to the closure of many LTCHs in the US, and it is unclear how closure of LTCHs may have affected upstream care patterns at short-stay hospitals and overall patient outcomes.

Objective

To estimate the association between LTCH closures and short-stay hospital care patterns and patient outcomes.

Design, Setting, and Participants

This retrospective, national, matched cohort study used difference-in-differences analysis to compare outcomes at short-stay hospitals reliant on LTCHs that closed during 2012 to 2018 with outcomes at control hospitals. Data were obtained from the Medicare Provider Analysis and Review File, 2011 to 2019. Participants included Medicare fee-for-service beneficiaries aged 66 years and older receiving MV for at least 96 hours in an intensive care unit (ie, patients at-risk for prolonged MV) and the subgroup also receiving a tracheostomy (ie, receiving prolonged MV). Data were analyzed from October 2022 to June 2023.

Exposure

Admission to closure-affected hospitals, defined as those discharging at least 60% of patients receiving a tracheostomy to LTCHs that subsequently closed, vs control hospitals.

Main Outcomes and Measures

Upstream hospital care pattern outcomes were short-stay hospital do-not-resuscitate orders, palliative care delivery, tracheostomy placement, and discharge disposition. Patient outcomes included hospital length of stay, days alive and institution free within 90 days, spending per days alive within 90 days, and 90-day mortality.

Results

Between 2011 and 2019, 99 454 patients receiving MV for at least 96 hours at 1261 hospitals were discharged to 459 LTCHs; 84 LTCHs closed. Difference-in-differences analysis included 8404 patients (mean age, 76.2 [7.2] years; 4419 [52.6%] men) admitted to 45 closure-affected hospitals and 45 matched-control hospitals. LTCH closure was associated with decreased LTCH transfer rates (difference, -5.1 [95% CI -8.2 to -2.0] percentage points) and decreased spending-per-days-alive (difference, -$8701.58 [95% CI, -$13 323.56 to -$4079.60]). In the subgroup of patients receiving a tracheostomy, there was additionally an increase in do-not-resuscitate rates (difference, 10.3 [95% CI, 4.2 to 16.3] percentage points) and transfer to skilled nursing facilities (difference, 10.0 [95% CI, 4.2 to 15.8] percentage points). There was no significant association of closure with 90-day mortality.

Conclusions and Relevance

In this cohort study, LTCH closure was associated with changes in discharge patterns in patients receiving mechanical ventilation for at least 96 hours and advanced directive decisions in the subgroup receiving a tracheostomy, without change in mortality. Further studies are needed to understand how LTCH availability may be associated with other important outcomes, including functional outcomes and patient and family satisfaction.

Emerging challenges of the impacts of pharmaceuticals on aquatic ecosystems: A diatom perspective

Pharmaceuticals are a ubiquitous group of emerging pollutants of considerable importance due to their biological potency and potential to elicit effects in wildlife and humans. Pharmaceuticals have been quantified in terrestrial, marine, fresh, and transitional waters, as well as the fauna and macro-flora that inhabit them. Pharmaceuticals can enter water ways through different human and veterinary pathways with traditional wastewater treatment, unable to completely remove pharmaceuticals, discharging often unknown quantities to aquatic ecosystems. However, there is a paucity of available information regarding the effects of pharmaceuticals on species at the base of aquatic food webs, especially on phytoplankton, with research typically focussing on fish and aquatic invertebrates. Diatoms are one of the main classes of phytoplankton and are some of the most abundant and important organisms in aquatic systems. As primary producers, diatoms generate ∼40 % of the world's oxygen and are a vital food source for primary consumers. Diatoms can also be used for bioremediation of polluted water bodies but perhaps are best known as bio-indicators for water quality studies. However, this keystone, non-target group is often ignored during ecotoxicological studies to assess the effects of pollutants of concern. Observed effects of pharmaceuticals on diatoms have the potential to be used as an indicator of pharmaceutical-induced impacts on higher trophic level organisms and wider ecosystem effects. The aim of this review is to present a synthesis of research on pharmaceutical exposure to diatoms, considering ecotoxicity, bioremediation and the role of diatoms as bio-indicators. We highlight significant omissions and knowledge gaps which need addressing to realise the potential role of diatoms in future risk assessment approaches and help evaluate the impacts of pharmaceuticals in the aquatic environment at local and global scales.

Comparative Effectiveness of Fludrocortisone and Hydrocortisone vs Hydrocortisone Alone Among Patients With Septic Shock

Importance

Patients with septic shock may benefit from the initiation of corticosteroids. However, the comparative effectiveness of the 2 most studied corticosteroid regimens (hydrocortisone with fludrocortisone vs hydrocortisone alone) is unclear.

Objective

To compare the effectiveness of adding fludrocortisone to hydrocortisone vs hydrocortisone alone among patients with septic shock using target trial emulation.

Design, Setting, and Participants

This retrospective cohort study from 2016 to 2020 used the enhanced claims-based Premier Healthcare Database, which included approximately 25% of US hospitalizations. Participants were adult patients hospitalized with septic shock and receiving norepinephrine who began hydrocortisone treatment. Data analysis was performed from May 2022 to December 2022.

Exposure

Addition of fludrocortisone on the same calendar day that hydrocortisone treatment was initiated vs use of hydrocortisone alone.

Main Outcome and Measures

Composite of hospital death or discharge to hospice. Adjusted risk differences were calculated using doubly robust targeted maximum likelihood estimation.

Results

Analyses included 88 275 patients, 2280 who began treatment with hydrocortisone-fludrocortisone (median [IQR] age, 64 [54-73] years; 1041 female; 1239 male) and 85 995 (median [IQR] age, 67 [57-76] years; 42 136 female; 43 859 male) who began treatment with hydrocortisone alone. The primary composite outcome of death in hospital or discharge to hospice occurred among 1076 (47.2%) patients treated with hydrocortisone-fludrocortisone vs 43 669 (50.8%) treated with hydrocortisone alone (adjusted absolute risk difference, -3.7%; 95% CI, -4.2% to -3.1%; P < .001).

Conclusions and Relevance

In this comparative effectiveness cohort study among adult patients with septic shock who began hydrocortisone treatment, the addition of fludrocortisone was superior to hydrocortisone alone.

Comparison of Propylthiouracil vs Methimazole for Thyroid Storm in Critically Ill Patients

Importance

Thyroid storm is the most severe form of thyrotoxicosis, with high mortality, and is treated with propylthiouracil and methimazole. Some guidelines recommend propylthiouracil over methimazole, although the difference in outcomes associated with each treatment is unclear.

Objective

To compare outcomes associated with use of propylthiouracil vs methimazole for the treatment of thyroid storm.

Design, Setting, and Participants

This comparative effectiveness study comprised a large, multicenter, US-based cohort from the Premier Healthcare Database between January 1, 2016, and December 31, 2020. It included 1383 adult patients admitted to intensive or intermediate care units with a diagnosis of thyroid storm per International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes and treated with either propylthiouracil or methimazole. Analyses were conducted from July 2022 to February 2023.

Exposure

Patients received either propylthiouracil or methimazole for treatment of thyroid storm. Exposure was assigned based on the initial thionamide administered.

Main Outcomes and Measures

The primary outcome was the adjusted risk difference of in-hospital death or discharge to hospice between patients treated with propylthiouracil and those treated with methimazole, assessed by targeted maximum likelihood estimation.

Results

A total of 1383 patients (656 [47.4%] treated with propylthiouracil; mean [SD] age, 45 [16] years; 473 women [72.1%]; and 727 [52.6%] treated with methimazole; mean [SD] age, 45 [16] years; 520 women [71.5%]) were included in the study. The standardized mean difference for age was 0.056, and the standardized mean difference for sex was 0.013. The primary composite outcome occurred in 7.4% of of patients (102 of 1383; 95% CI, 6.0%-8.8%). A total of 8.5% (56 of 656; 95% CI, 6.4%-10.7%) of patients who initiated propylthiouracil and 6.3% (46 of 727; 95% CI, 4.6%-8.1%) who initiated methimazole died in the hospital (adjusted risk difference, 0.6% [95% CI, -1.8% to 3.0%]; P = .64). There were no significant differences in duration of organ support, total hospitalization costs, or rates of adverse events between the 2 treatment groups.

Conclusion and Relevance

In this comparative effectiveness study of a multicenter cohort of adult patients with thyroid storm, no significant differences were found in mortality or adverse events in patients who were treated with propylthiouracil or methimazole. Thus, current guidelines recommending propylthiouracil over methimazole for treatment of thyroid storm may merit reevaluation.

Hospital-level variation in practices and outcomes for patients with severe acute exacerbations of idiopathic pulmonary fibrosis: a retrospective multicentre cohort study

BACKGROUND

In the absence of evidence-based strategies to improve patient outcomes, the management of patients with severe idiopathic pulmonary fibrosis (IPF) exacerbations may vary widely across centres. We assessed between-hospital variation in practices and mortality for patients with severe IPF exacerbations.

METHODS

Using the Premier Healthcare Database from 1 October 2015 to 31 December 2020, we identified patients admitted to intensive care unit (ICU) or intermediate care unit with an IPF exacerbation. We assessed idiosyncratic, between-hospital variation in ICU practices (invasive mechanical ventilation (IMV), non-invasive mechanical ventilation (NIMV), corticosteroid use, and immunosuppressive and/or antioxidant use) and hospital mortality by determining median risk-adjusted hospital rates and intraclass correlation coefficients (ICCs) from hierarchical multivariable regression models. A priori, an ICC>15% was deemed 'high variation'.

RESULTS

We identified 5256 critically ill patients with a severe IPF exacerbation at 385 US hospitals. Hospital median risk-adjusted rates of practices were: IMV (14% (IQR: 8.3%-26%)), NIMV (42% (31%-54%)), corticosteroid use (89% (84%-93%)), and immunosuppressive and/or antioxidant use (3.3% (1.9%-5.8%)). Model ICCs were: IMV (19% (95% CI: 18% to 21%)), NIMV (15% (13% to 16%)), corticosteroid use (9.8% (8.3% to 11%)), and immunosuppressive and/or antioxidant use (8.5% (7.1% to 9.9%)). The median risk-adjusted hospital mortality was 16% (IQR: 11%-24%) with an ICC of 7.5% (95% CI: 6.2% to 8.9%).

INTERPRETATION

We observed high variation in the use of IMV and NIMV, and less variation in corticosteroid and immunosuppressant and/or antioxidant use among patients hospitalised with severe IPF exacerbations. Further research is needed to guide the decisions surrounding initiation of IMV and role of NIMV and to understand the effectiveness of corticosteroids among patients with severe IPF exacerbations.

Practice Changes Among Patients Without COVID-19 Receiving Mechanical Ventilation During the Early COVID-19 Pandemic

The COVID-19 pandemic led to rapid changes in care delivery for critically ill patients, due to factors including increased numbers of ICU patients, shifting staff roles, and changed care locations. As these changes may have impacted the care of patients without COVID-19, we assessed changes in common ICU practices for mechanically ventilated patients with non-COVID acute respiratory failure at the onset of and during the COVID-19 pandemic.

DESIGN

Interrupted time series analysis, adjusted for seasonality and autocorrelation where present, evaluating trends in common ICU practices prior to the pandemic (March 2016 to February 2020), at the onset of the pandemic (April 2020) and intra-pandemic (April 2020 to December 2020).

SETTING

Premier Healthcare Database, containing data from 25% of U.S. discharges from January 1, 2016, to December 31, 2020.

PATIENTS

Patients without COVID-19 receiving mechanical ventilation for acute respiratory failure.

INTERVENTIONS

We assessed monthly rates of chest radiograph (CXR), chest CT scans, lower extremity noninvasive vascular testing (LENI), bronchoscopy, arterial catheters, and central venous catheters.

MEASUREMENTS AND MAIN RESULTS

We identified 742,096 mechanically ventilated patients without COVID-19 at 545 hospitals. At the onset of the pandemic, CXR (-0.5% [-0.9% to -0.2%; p = 0.001]), LENI (LENI: -2.1% [-3.3% to -0.9%; p = 0.001]), and bronchoscopy rates (-1.0% [-1.5% to -0.6%; p < 0.001]) decreased; use of chest CT increased (1.5% [0.5-2.5%; p = 0.006]). Use of arterial lines and central venous catheters did not change significantly. Intra-pandemic, LENI (0.5% [0.3-0.7%; p < 0.001]/mo) and bronchoscopy (0.1% [0.05-0.2%; p < 0.001]/mo) trends increased relative to pre-pandemic trends, while the remainder of practices did not change significantly.

CONCLUSIONS

We observed several statistically significant changes to practice patterns among patients without COVID-19 early during the pandemic. However, most of the changes were small or temporary, suggesting that routine practices in the care of mechanically ventilated patients in the ICU was not drastically affected by the pandemic.

Inhaled Nitric Oxide vs Epoprostenol During Acute Respiratory Failure: An Observational Target Trial Emulation

BACKGROUND

The inhaled vasodilators nitric oxide and epoprostenol may be initiated to improve oxygenation in mechanically ventilated patients with severe acute respiratory failure (ARF); however, practice patterns and head-to-head comparisons of effectiveness are unclear.

RESEARCH QUESTION

What are the practice patterns and comparative effectiveness for inhaled nitric oxide and epoprostenol in severe ARF?

STUDY DESIGN AND METHODS

Using a large US database (Premier Healthcare Database), we identified adult patients with ARF or ARDS who were mechanically ventilated and started on inhaled nitric oxide, epoprostenol, or both. Leveraging large hospital variation in the choice of initial inhaled vasodilator, we compared the effectiveness of inhaled nitric oxide with that of epoprostenol by limiting analysis to patients admitted to hospitals that exclusively used either inhaled nitric oxide or epoprostenol. The primary outcome of successful extubation was modeled using multivariate Fine-Grey competing risk (death or hospice discharge) time-to-event models.

RESULTS

Among 11,200 patients (303 hospitals), 6,366 patients (56.8%) received inhaled nitric oxide first, 4,720 patients (42.1%) received inhaled epoprostenol first, and 114 patients (1.0%) received both therapies on the same day. One hundred four hospitals (34.3%; 1,666 patients) exclusively used nitric oxide and 118 hospitals (38.9%; 1,812 patients) exclusively used epoprostenol. No differences were found in the likelihood of successful extubation between patients admitted to nitric oxide-only hospitals vs those admitted to epoprostenol-only hospitals (subdistribution hazard ratio, 0.97; 95% CI, 0.80-1.18). Also no differences were found in total hospital costs or death. Results were robust to multiple sensitivity analyses.

INTERPRETATION

Large variation exists in the use of initial inhaled vasodilator for respiratory failure across US hospitals. Comparative effectiveness analyses identified no differences in outcomes based on inhaled vasodilator type.

Comparison of Heart Rate After Phenylephrine vs Norepinephrine Initiation in Patients With Septic Shock and Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is a common complication of sepsis. It is unclear whether norepinephrine, an α- and β-agonist, and phenylephrine, an α-agonist, are associated with different heart rates among patients with sepsis and AF.

RESEARCH QUESTION

Among patients with sepsis and AF, what is the difference in heart rate after phenylephrine initiation vs norepinephrine initiation?

STUDY DESIGN AND METHODS

With the use of an extensive database, we identified patients with sepsis and AF at the time of norepinephrine or phenylephrine initiation. We estimated the difference in heart rate between patients who received phenylephrine or norepinephrine 1 and 6 h after vasopressor initiation with the use of multivariable-adjusted linear regression, tested for effect modification by heart rate, and stratified by baseline heart rate ≥ 110 or < 110 beats/min. Secondary outcomes included conversion to sinus rhythm, bradycardia, vasopressor duration, ICU and hospital length of stay, and hospital death. Exploratory analyses were adjusted for practices that occurred after vasopressor initiation; sensitivity analyses used interrupted time series to estimate the difference in average heart rate between patients who received phenylephrine or norepinephrine.

RESULTS

Among 1847 patients with sepsis and AF, 946 patients (51%) received norepinephrine, and 901 patients (49%) received phenylephrine. After multivariable adjustment, phenylephrine was associated with a lower heart rate at 1 h (-4 beats/min; 95% CI, -6 to -1; P < .001) and 6 h (-4 beats/min; 95% CI, -6 to -1; P = .004). Higher heart rate before vasopressor administration was associated with larger heart rate reduction in patients who received phenylephrine compared with norepinephrine. There were no differences in secondary outcomes. Results were similar in exploratory and sensitivity analyses.

INTERPRETATION

In patients with sepsis and AF, the initiation of phenylephrine was associated with modestly lower heart rate compared with norepinephrine. Heart rate at vasopressor initiation appeared to be an important effect modifier. Whether modest reductions in heart rate are associated with clinical outcomes requires further study.

CE: A Prone Positioning Protocol for Awake, Nonintubated Patients with COVID-19

ABSTRACT

Prone positioning of critically ill patients with acute respiratory distress syndrome is an accepted therapy done to improve oxygenation and promote weaning from mechanical ventilation. But there is limited information regarding its use outside of the ICU. At one Boston hospital, the influx of patients with suspected or confirmed COVID-19 strained its resources, requiring sweeping systems changes and inspiring innovations in clinical care. This article describes how an interdisciplinary team of clinicians developed a prone positioning protocol for use with awake, nonintubated, oxygen-dependent patients with suspected or confirmed COVID-19 on medical-surgical units, with the hope of hastening their recovery and avoiding deterioration and ICU transfer. A protocol implementation plan and staff educational materials were disseminated via the hospital incident command system and supported through daily leadership huddles. Patient eligibility criteria, including indications and contraindications, and a clear nursing procedure for the implementation of prone positioning with a given patient, were key elements. Nurses' feedback of their experiences with the protocol was elicited through an e-mailed survey. Nearly all respondents reported improvements in patients' oxygen saturation levels, while few respondents reported barriers to protocol implementation. The prone positioning protocol was found to be both feasible for and well tolerated by awake, nonintubated patients on medical-surgical units, and can serve as an example for other hospitals during this pandemic.

Gastrostomy Tube Use in the Critically Ill, 1994-2014

Rationale: Although gastrostomy tubes have shown to be of limited benefit in patients with advanced dementia, they continue to be used to deliver nutritional support in critically ill patients. The epidemiology and short-term outcomes are unclear. Objectives: To quantify national practice patterns and short-term outcomes of gastrostomy tube placement among the critically ill over the last two decades in the United States. Methods: Using the U.S. Agency for Healthcare and Research Quality's Healthcare Cost and Utilization Project's National Inpatient Sample, we evaluated trends in annual population-standardized rates of gastrostomy tube placement among critically ill adults from 1994 to 2014; we also quantified trends in length of stay, in-hospital mortality, and discharge location. We conducted sensitivity analyses among mechanically ventilated patients, survivors, and decedents of critical illness, and in a critically ill population excluding patients with dementia. Results: From 1994 to 2014, population-based rates of gastrostomy tube use in critically ill patients increased from 11.9 to 28.8 gastrostomies per 100,000 U.S. adults (peak in incidence in 2010), an increase of 142% (31,392-91,990 gastrostomy tubes in critically ill patients; P < 0.001). Patients receiving gastrostomy tubes during critical illness occupied a growing proportion of all gastrostomy tube placements, accounting for 19.6% of all gastrostomy tubes placed in 1994 and 50.8% in 2014. The rate of gastrostomies in critically ill patients remained roughly stable, from 2.5% of critically ill patients in 1994 to a peak of 3.7% in 2002 before declining again to 2.4% in 2014. Hospital length of stay and in-hospital mortality decreased among gastrostomy tube recipients (28.7 d to 20.5 d, P < 0.001; 25.9-11.3%, P < 0.001; respectively), whereas discharges to long-term facilities increased significantly (49.6-70.6%; P < 0.001). Sensitivity analyses among mechanically ventilated patients revealed similar increases in population-based estimates of gastrostomy tube placement. Conclusions: The incidence of gastrostomy tube placement among critically ill patients more than doubled between 1994 and 2014, with most patients being discharged to long-term care facilities. Critically ill patients are now the primary utilizer of gastrostomy tubes placed in the United States. Additional research is needed to better characterize the long-term risk and benefits of gastrostomy tube use in critically ill patients.

Failures in the Respectful Care of Critically Ill Patients

BACKGROUND

The emotional toll of critical illness on patients and their families can be profound and is emerging as an important target for value improvement. One source of emotional harm to patients and families may be care perceived as inadequately respectful. The prevalence and risk factors for types of emotional harms is under-studied.

METHODS

This prospective cohort study was conducted in nine ICUs at a tertiary care academic medical center in the United States. Prevalence of inadequate respect for (a) the patient and (b) the family, as well as prevalence of perceived lack of control over the care of their loved ones, was assessed by the Family Satisfaction with Care in the Intensive Care Unit instrument. The relationship between these outcomes with demographic and clinical covariates was assessed. Stratification by patient survivorship was performed in sensitivity analysis.

RESULTS

Of more than 1,500 respondents, 16.9% and 21.8% reported that the patient or the family member, respectively, received inadequate respect. No clinical characteristics of the patients were associated with inadequate respect for either the patient or the family member. By comparison, more than half of respondents reported a lack of control over their loved one's care; this finding was associated with multiple clinical factors. Prevalence and associated factors differed by patient survivorship status.

CONCLUSION

Care that is inadequately respectful to patients and families in the setting of critical illness is prevalent but does not appear to be associated with clinical characteristics. The incidence of such emotional harms is nuanced, difficult to predict, and deserves further investigation.

Occult catheter rupture causing episodic symptoms in a patient treated with epoprostenol

Infection, thrombosis, and catheter dislodgment are well-recognized potential complications of chronic intravenous prostanoid therapy for pulmonary arterial hypertension. As long-term outcomes of pulmonary hypertension patients improve, novel adverse events are likely to arise. We describe the sudden development of unexplained hypotension and lightheadedness in a patient receiving intravenous epoprostenol for several years, ultimately determined to be due to an unusual catheter complication, not previously described in this population.

A Multipotent Progenitor Domain Guides Pancreatic Organogenesis

The mammalian pancreas is constructed during embryogenesis by multipotent progenitors, the identity and function of which remain poorly understood. We performed genome-wide transcription factor expression analysis of the developing pancreas to identify gene expression domains that may represent distinct progenitor cell populations. Five discrete domains were discovered. Genetic lineage-tracing experiments demonstrate that one specific domain, located at the tip of the branching pancreatic tree, contains multipotent progenitors that produce exocrine, endocrine, and duct cells in vivo. These multipotent progenitors are Pdx1(+)Ptf1a(+)cMyc(High)Cpa1(+) and negative for differentiated lineage markers. The outgrowth of multipotent tip cells leaves behind differentiated progeny that form the trunk of the branches. These findings define a multipotent compartment within the developing pancreas and suggest a model of how branching is coordinated with cell type specification. In addition, this comprehensive analysis of >1,100 transcription factors identified genes that are likely to control critical decisions in pancreas development and disease.

Beta-catenin is essential for pancreatic acinar but not islet development

Despite our increasingly sophisticated understanding of transcriptional regulation in pancreas development, we know relatively little about the extrinsic signaling pathways involved in this process. We show here that the early pancreatic epithelium exhibits a specific enrichment in unphosphorylated beta-catenin protein, a hallmark of activation of the canonical Wnt signaling pathway. To determine if this pathway is functionally required for normal pancreas development, we have specifically deleted the beta-catenin gene in these cells. Pancreata developing without beta-catenin are hypoplastic, although their early progenitors appear normal and exhibit no premature differentiation or death. Surprisingly, and in marked contrast to its role in the intestine, loss of beta-catenin does not significantly perturb islet endocrine cell mass or function. The major defect of the beta-catenin-deficient pancreas is an almost complete lack of acinar cells, which normally comprise the majority of the organ. beta-Catenin appears to be cell-autonomously required for the specification of acinar cells, rather than for their survival or maintenance, as deletion of beta-catenin specifically in differentiated acinar cells has no effect. Thus, our data are consistent with a crucial role for canonical Wnt signals in acinar lineage specification and differentiation.

The effects of N omega-nitro-L-arginine methyl ester, sodium nitroprusside and noradrenaline on venous return in the anaesthetized cat

1. The vascular actions of N omega-nitro-L-arginine methyl ester (L-NAME), sodium nitroprusside and noradrenaline were investigated in cats under chloralose anaesthesia with controlled vascular tone and ventilation. Cardiac output, heart rate, vascular pressures and mean circulatory filling pressure (MCFP) were measured. Total peripheral resistance (TPR) and resistance to venous return (Rvr) were calculated from steady-state readings. 2. L-NAME (37 mumol kg-1, i.v.) administered to ten cats receiving noradrenaline (6 nmol kg-1 min-1, i.v.) increased aortic pressure by 47.5 +/- 7.1 mmHg from 106 mmHg, and MCFP by 1.56 +/- 0.36 mmHg from 10.0 mmHg (means +/- s.e. means). Mean changes in portal venous pressure, RAP and heart rate were not significant. Cardiac output fell by 29.7 +/- 3.3% from 130 ml min-1 kg-1. TPR rose by 108 +/- 7.2% from 796 mmHg l-1 min kg and Rvr by 58.4 +/- 4.5% from 64 mmHg l-1 min kg. 3. Infusion of sodium nitroprusside into cats receiving noradrenaline evoked dose-related falls in aortic pressure, MCFP, TPR and Rvr. Changes in portal venous pressure, RAP and heart rate were not significant and cardiac output fell slightly. After L-NAME, sensitivity to nitroprusside was increased by 139 +/- 34% for MCFP, 176 +/- 19% for TPR and 351 +/- 39% for Rvr, and cardiac output rose slightly. The nitroprusside infusion required to restore TPR after L-NAME was estimated to be 5.8 x 10(+/- 0.41) nmol kg-1 min-1, which was approximately three times more than that required to restore MCFP. 4. Infusion of noradrenaline evoked dose-related increases in aortic and portal venous pressures, heart rate, cardiac output, MCFP, TPR and Rvr. After L-NAME and nitroprusside (4.4 nmol kg-1 min-1, i.v.),TPR and Rvr were not significantly different, but MCFP was reduced by 1.76 +/- 0.24 mmHg, and cardiac output by 22 +/- 1.9%. After subsequent expansion of the circulating blood volume (5-7.5 ml kg-1 dextran-saline), mean values for all parameters were restored to their previous levels. Sensitivity to noradrenaline was not significantly altered for heart rate, TPR and Rvr but was reduced by 31.8 +/- 12%for MCFP and by 66.5 +/- 18% for cardiac output.5. The depression of cardiac output by L-NAME is attributed to the increase in Rvr, partly compensated by the rise in MCFP. For a given rise in MCFP, the increase in R, was seven times greater after L-NAME than after noradrenaline, and the difference in the relative actions of the two drugs on resistance and capacitance vessels largely accounts for their contrasting effects on venous return. A procedure is suggested for replacement of vascular nitric oxide by nitroprusside infusion and blood volume expansion.