Accuracy of Noninvasive Blood Pressure Monitoring in Critically Ill Adults

BACKGROUND

Blood pressure (BP) is routinely invasively monitored by an arterial catheter in the intensive care unit (ICU). However, the available data comparing the accuracy of noninvasive methods to arterial catheters for measuring BP in the ICU are limited by small numbers and diverse methodologies.

PURPOSE

To determine agreement between invasive arterial blood pressure monitoring (IABP) and noninvasive blood pressure (NIBP) in critically ill patients.

METHODS

This was a single center, observational study of critical ill adults in a tertiary care facility evaluating agreement (≤10% difference) between simultaneously measured IABP and NIBP. We measured clinical features at time of BP measurement inclusive of patient demographics, laboratory data, severity of illness, specific interventions (mechanical ventilation and dialysis), and vasopressor dose to identify particular clinical scenarios in which measurement agreement is more or less likely.

RESULTS

Of the 1852 critically ill adults with simultaneous IABP and NIBP readings, there was a median difference of 6 mm Hg in mean arterial pressure (MAP), interquartile range (1-12), P < .01. A logistic regression analysis identified 5 independent predictors of measurement discrepancy: increasing doses of norepinephrine (adjusted odds ratio [aOR] 1.10 [95% confidence interval, CI 1.08-1.12] P = .03 for every change in 5 µg/min), lower MAP value (aOR 0.98 [0.98-0.99] P < .01 for every change in 1 mm Hg), higher body mass index (aOR 1.04 [1.01-1.09] P = .01 for an increase in 1), increased patient age (aOR 1.31 [1.30-1.37] P < .01 for every 10 years), and radial arterial line location (aOR 1.74 [1.16-2.47] P = .04).

CONCLUSIONS

There was broad agreement between IABP and NIBP in critically ill patients over a range of BPs and severity of illness. Several variables are associated with measurement discrepancy; however, their predictive capacity is modest. This may guide future study into which patients may specifically benefit from an arterial catheter.

Predicting Impact of Prone Position on Oxygenation in Mechanically Ventilated Patients with COVID-19

OBJECTIVES

Prone positioning is widely used in mechanically ventilated patients with COVID-19; however, the specific clinical scenario in which the individual is most poised to benefit is not fully established. In patients with COVID-19 respiratory failure requiring mechanical ventilation, how effective is prone positioning in improving oxygenation and can that response be predicted?

DESIGN

This is a retrospective observational study from two tertiary care centers including consecutive patients mechanically ventilated for COVID-19 from 3/1/2020 - 7/1/2021. The primary outcome is improvement in oxygenation as measured by PaO₂/FiO₂. We describe oxygenation before, during and after prone episodes with a focus on identifying patient, respiratory or ventilator variables that predict prone positioning success.

SETTING

2 Tertiary Care Academic Hospitals.

PATIENTS

125 patients mechanically ventilated for COVID-19 respiratory failure.

INTERVENTIONS

Prone positioning.

MAIN RESULTS

One hundred twenty-five patients underwent prone positioning a total of 309 times for a median duration of 23 hours IQR (14 - 49). On average, PaO₂/FiO₂ improved 19%: from 115 mm Hg (80 - 148) immediately before proning to 137 mm Hg (95 - 197) immediately after returning to the supine position. Prone episodes were more successful if the pre-prone PaO₂/FiO₂ was lower and if the patient was on inhaled epoprostenol (iEpo). For individuals with severe acute respiratory distress syndrome (ARDS) (PaO₂/FiO₂ < 100 prior to prone positioning) and on iEpo, the median improvement in PaO₂/FiO₂ was 27% in both instances.

CONCLUSIONS

Prone positioning in mechanically ventilated patients with COVID-19 is generally associated with sustained improvements in oxygenation, which is made more likely by the concomitant use of iEpo and is more impactful in those who are more severely hypoxemic prior to prone positioning.

Healthcare Worker With Large Vessel Acute Ischemic Stroke Likely Related to Mild SARS-CoV-2 Infection

We report the case of a healthcare worker who presented with a large vessel acute ischemic stroke in setting of a mild SARS-CoV-2 infection and provide a review of the emerging literature on COVID-related stroke. A 43-year-old female presented with right-sided hemiparesis, aphasia and dysarthria. She had a nonproductive of cough for 1 week without fever, fatigue or dyspnea. A CT Head, CT angiography and CT perfusion imaging revealed a M1 segment occlusion of the left middle cerebral artery requiring transfer from a primary to a comprehensive stroke center. A nasopharyngeal swab confirmed SARS-CoV-2 infection prior to arrival at the accepting center. During the thrombectomy a 3 cm thrombus was removed. Thrombus was also evident in the 8 French short sheath during closure device placement so a hypercoagulable state was suspected. Stroke work-up revealed a glycosylated hemoglobin of 8.7%, elevation of inflammatory markers and an indeterminate level of lupus anticoagulant IgM. On discharge home, she had near complete neurological recovery. This case highlights suspected mechanisms of hypercoagulability in SARS-CoV-2 infection and the importance of optimizing stroke care systems during the COVID-19 pandemic.

Outcomes of renal replacement therapy in the critically ill with COVID-19

Objective

To describe outcomes of critically ill patients with COVID-19, particularly the association of renal replacement therapy to mortality.

Design

A single-center prospective observational study was carried out.

Setting

ICU of a tertiary care center.

Patients

Consecutive adults with COVID-19 admitted to the ICU.

Intervention

Renal replacement therapy.

Main variables of interest

Demographic data, medical history, illness severity, type of oxygen therapy, laboratory data and use of renal replacement therapy to generate a logistic regression model describing independent risk factors for mortality.

Results

Of the total of 166 patients, 51% were mechanically ventilated and 26% required renal replacement therapy. The overall hospital mortality rate was 36%, versus 56% for those requiring renal replacement therapy, and 68% for those with both mechanical ventilation and renal replacement therapy. The logistic regression model identified four independent risk factors for mortality: age (adjusted OR 2.8 [95% CI 1.8–4.4] for every 10-year increase), mechanical ventilation (4.2 [1.7–10.6]), need for continuous venovenous hemofiltration (2.3 [1.3–4.0]) and C-reactive protein (1.1 [1.0–1.2] for every 10 mg/L increase).

Conclusions

In our cohort, acute kidney injury requiring renal replacement therapy was associated to a high mortality rate similar to that associated to the need for mechanical ventilation, while multiorgan failure necessitating both techniques implied an extremely high mortality risk.

Fluid Balance Predicts Need for Intubation in Subjects With Respiratory Failure Initiated on High-Flow Nasal Cannula

BACKGROUND

High-flow nasal cannula (HFNC) has gained widespread use for acute hypoxemic respiratory failure on the basis of recent publications that demonstrated fewer intubations and perhaps lower mortality in certain situations. However, a subset of patients initiated on HFNC for respiratory failure ultimately do require intubation. Our goal was to identify patient-level features predictive of this outcome.

METHODS

This was a retrospective cohort study of subjects with hypoxemic respiratory failure treated with HFNC. Individuals were described as having succeeded (if weaned from HFNC) or failed (if they required intubation). A variety of easily measurable variables were evaluated for their ability to predict intubation risk, analyzed via a multivariate logistic regression model.

RESULTS

Of a total of 74 subjects, 42 succeeded and 32 failed. The mean ± SD net fluid balance in the first 24 h after HFNC initiation was significantly lower in the success group versus the failure group (-33 ± 80 mL/h vs 72 ± 117 mL/h; P < .01). An adjusted model found only fluid balance and the previously described respiratory rate (breathing frequency [f]) to oxygenation (ROX) index ([[Formula: see text]/[Formula: see text]]/f) at 12 h as significant predictors of successful weaning (negative fluid balance adjusted odds ratio 0.77 [95% CI 0.62-0.96] for -10 mL/h increments [P = .02]; ROX adjusted OR 1.72 [1.15-2.57], P < .01).

CONCLUSIONS

A negative fluid balance while on HFNC discriminated well between those who required intubation versus those who were successfully weaned.

Outcomes of renal replacement therapy in the critically ill with COVID-19

Objective

To describe outcomes of critically ill patients with COVID-19, particularly the association of renal replacement therapy to mortality.

Design

A single-center prospective observational study was carried out.

Setting

ICU of a tertiary care center.

Patients

Consecutive adults with COVID-19 admitted to the ICU.

Intervention

Renal replacement therapy.

Main variables of interest

Demographic data, medical history, illness severity, type of oxygen therapy, laboratory data and use of renal replacement therapy to generate a logistic regression model describing independent risk factors for mortality.

Results

Of the total of 166 patients, 51% were mechanically ventilated and 26% required renal replacement therapy. The overall hospital mortality rate was 36%, versus 56% for those requiring renal replacement therapy, and 68% for those with both mechanical ventilation and renal replacement therapy. The logistic regression model identified four independent risk factors for mortality: age (adjusted OR 2.8 [95% CI 1.8–4.4] for every 10-year increase), mechanical ventilation (4.2 [1.7–10.6]), need for continuous venovenous hemofiltration (2.3 [1.3–4.0]) and C-reactive protein (1.1 [1.0–1.2] for every 10 mg/L increase).

Conclusions

In our cohort, acute kidney injury requiring renal replacement therapy was associated to a high mortality rate similar to that associated to the need for mechanical ventilation, while multiorgan failure necessitating both techniques implied an extremely high mortality risk.

Responsiveness of Inhaled Epoprostenol in Respiratory Failure due to COVID-19

BACKGROUND

Inhaled pulmonary vasodilators are used as adjunctive therapies for the treatment of refractory hypoxemia. Available evidence suggest they improve oxygenation in a subset of patients without changing long-term trajectory. Given the differences in respiratory failure due to COVID-19 and "traditional" ARDS, we sought to identify their physiologic impact.

METHODS

This is a retrospective observational study of patients mechanically ventilated for COVID-19, from the ICUs of 2 tertiary care centers, who received inhaled epoprostenol (iEpo) for the management of hypoxemia. The primary outcome is change in PaO₂/FiO₂. Additionally, we measured several patient level features to predict iEpo responsiveness (or lack thereof).

RESULTS

Eighty patients with laboratory confirmed SARS-CoV2 received iEpo while mechanically ventilated and had PaO₂/FiO₂ measured before and after. The median PaO₂/FiO₂ prior to receiving iEpo was 92 mmHg and interquartile range (74 - 122). The median change in PaO₂/FiO₂ was 9 mmHg (-9 - 37) corresponding to a 10% improvement (-8 - 41). Fifty-percent (40 / 80) met our a priori definition of a clinically significant improvement in PaO₂/FiO₂ (increase in 10% from the baseline value). Prone position and lower PaO₂/FiO₂ when iEpo was started predicted a more robust response, which held after multivariate adjustment. For proned individuals, improvement in PaO₂/FiO₂ was 14 mmHg (-6 to 45) vs. 3 mmHg (-11 - 20), p = 0.04 for supine individuals; for those with severe ARDS (PaO₂/FiO₂ < 100, n = 49) the median improvement was 16 mmHg (-2 - 46).

CONCLUSION

Fifty percent of patients have a clinically significant improvement in PaO₂/FiO₂ after the initiation of iEpo. This suggests it is worth trying as a rescue therapy; although generally the benefit was modest with a wide variability. Those who were prone and had lower PaO₂/FiO₂ were more likely to respond.

Multimodal noninvasive prediction of pulmonary hypertension in IPF

INTRODUCTION AND OBJECTIVE

Pulmonary hypertension (PH) complicating idiopathic pulmonary fibrosis (IPF) is challenging to diagnose given inaccuracy of transthoracic echocardiogram (TTE) measurements. However, it has significant prognostic implications and is therefore important to accurately identify.

METHODS

We conducted a cross-sectional study of patients with IPF who underwent RHC as part of their evaluation. A variety of commonly available noninvasive variables were evaluated for their ability to predict pulmonary arterial pressure in a linear regression model, including the traditionally used right ventricular systolic pressure (RVSP) estimated from TTE.

RESULTS

There were 105 eligible patients identified from January 2006 to July 2016. The average age was 62.7 ± 7.7 years, 35 had RHC proven PH and 43% ultimately underwent lung transplantation. A linear model including three terms: RVSP (ANOVA P < .01), the ratio of FVC/DLCO from PFTs (P = .05) and pulmonary artery to aorta diameter ratio from CT (P < .01) was found to predict the mean pulmonary artery pressure more reliably than RVSP alone (R² .39 vs .29, P < .05), with a lower rate of incorrect classification of PH status in these individuals (27.6 vs 35.2%, P = .05) and high negative predictive value (87.2%).

CONCLUSION

If used in conjunction with RVSP from TTE, parameters from PFTs and the CT scan more accurately predict the presence or absence of PH than any of the variables in isolation. Using these in concert may allow greater discrimination in deciding which patients to subject to diagnostic right heart catheterization.

Modeling risk for developing drug resistant bacterial infections in an MDR-naive critically ill population

PURPOSE

To create a model predictive of an individual's risk of developing a de novo multidrug-resistant (MDR) infection while in the intensive care unit (ICU).

METHODS

This is a case-control study in which 189 ICU patients diagnosed with their first infection with an MDR organism were compared on the basis of demographic, past medical and clinical variables to randomly selected ICU patients without such an infection, era-matched in a 2:1 ratio. A prediction tool was derived using multivariate logistic regression.

RESULTS

Five features remained predictive of developing an infection with a drug-resistant pathogen: hospitalization within a year [adjusted odds ratio (OR) 2.14], chronic hemodialysis (3.86), underlying oxygen-dependent pulmonary disease (1.86), endotracheal intubation within 24 h (2.46) and reason for ICU admission (respiratory failure 2.89, non-respiratory failure, non-shock presentation 1.85). Using a scoring system (0-7 points) based on the adjusted OR, risk categories were derived (low: 0-2 points, intermediate: 3-4 points and high risk: 5-7 points). The negative predictive value at a score cutoff of 2 is excellent (88.9%).

CONCLUSIONS

A clinical prediction rule comprised of five easily measured ICU variables reasonably discriminates between patients who will develop their first MDR infection versus those who will not.

Cholesterol, lipoproteins and subclinical interstitial lung disease: the MESA study

We investigated associations of plasma lipoproteins with subclinical interstitial lung disease (ILD) by measuring high attenuation areas (HAA: lung voxels between -600 and -250 Hounsfield units) in 6700 adults and serum MMP-7 and SP-A in 1216 adults age 45-84 without clinical cardiovascular disease in Multi-Ethnic Study of Atherosclerosis. In cross-sectional analyses, each SD decrement in high density lipoprotein cholesterol (HDL-C) was associated with a 2.12% HAA increment (95% CI 1.44% to 2.79%), a 3.53% MMP-7 increment (95% CI 0.93% to 6.07%) and a 6.37% SP-A increment (95% CI 1.35% to 11.13%), independent of demographics, smoking and inflammatory biomarkers. These findings support a novel hypothesis that HDL-C might influence subclinical lung injury and extracellular matrix remodelling.

E-Cigarettes: The Science Behind the Smoke and Mirrors

E-cigarettes are a diverse set of devices that are designed for pulmonary delivery of nicotine through an aerosol, usually consisting of propylene glycol, nicotine, and flavorings. The devices heat the nicotine solution using a battery-powered circuit and deliver the resulting vapor into the proximal airways and lung. Although the current devices on the market appear to be safer than smoking combusted tobacco, they have their own inherent risks, which remain poorly characterized due to widespread product variability. Despite rising use throughout the United States, predominantly by smokers, limited evidence exists for their efficacy in smoking cessation. Pending regulation by the FDA will enforce limited disclosures on the industry but will not directly impact safety or efficacy. Meanwhile, respiratory health practitioners will need to tailor their discussions with patients, taking into account the broad range of existing effective smoking cessation techniques, including pharmaceutical nicotine replacement therapy.

Fusobacterium necrophorum presenting as isolated lung nodules

Fusobacterium necrophorum causes Lemierre's syndrome - a dramatic and distinct condition beginning with pharyngitis before proceeding to internal jugular vein septic thrombophlebitis and respiratory tract infection in otherwise healthy individuals. It is rare, but by far the most common pathway to parenchymal lung disease with this organism. Here we describe we a 34 year old healthy lady who was nontoxic without any antecedent illness who presented with lung nodules due to fusobacterium necrophorum as the sole manifestation of disease. Leading diagnostic consideration prior to culture data was pulmonary vasculitis. Identifying her disease process was a somewhat chance occurrence, and it began to resolve prior to antibiotic therapy. Though it would be difficult to recommend keen awareness of this organism given its rarity, it is important to consider that its scope may be broader than traditionally considered.

Impact of the 2009 influenza A (H1N1) pandemic on healthcare workers at a tertiary care center in New York City

BACKGROUND AND OBJECTIVE

Assessing the impact of 2009 influenza A (H1N1) on healthcare workers (HCWs) is important for pandemic planning.

METHODS

We retrospectively analyzed employee health records of HCWs at a tertiary care center in New York City with influenza-like illnesses (ILI) and confirmed influenza from March 31, 2009, to February 28, 2010. We evaluated HCWs' clinical presentations during the first and second wave of the pandemic, staff absenteeism, exposures among HCWs, and association between high-risk occupational exposures to respiratory secretions and infection.

RESULTS

During the pandemic, 40% (141/352) of HCWs with ILI tested positive for influenza, representing a 1% attack rate among our 13,066 employees. HCWs with influenza were more likely to have fever, cough, and tachycardia. When compared with the second wave, cases in the first wave were sicker and at higher risk of exposure to patients' respiratory secretions (P=.049). HCWs with ILI--with and without confirmed influenza--missed on average 4.7 and 2.7 work days, respectively (P=.001). Among HCWs asked about working while ill, 65% (153/235) reported they did so (mean, 2 days).

CONCLUSIONS

HCWs in the first wave had more severe ILI than those in the second wave and were more likely to be exposed to patients' respiratory secretions. HCWs with ILI often worked while ill. Timely strategies to educate and support HCWs were critical to managing this population during the pandemic.