Development and Implementation of an Acute Kidney Injury Remote Patient Monitoring Program: Research Letter

Acute kidney injury (AKI) survivors have a dynamic posthospital course which warrants close monitoring. Remote patient monitoring (RPM) could be used to improve quality and efficiency of AKI survivor care.

Objective

The objective of this report was to describe the development and preliminary feasibility of an AKI RPM program launched in October 2021.

Setting

Academic medical center.

Patients

Patients enrolled in the AKI RPM program were those who experienced AKI during a hospitalization and underwent nephrology consultation.

Measurements/Methods

At enrollment, patients were provided with home monitoring technology and underwent weekly laboratory assessments. Nurses evaluated the data daily and adhered to prespecified protocols for management and escalation of care if needed.

Results

Twenty patients were enrolled in AKI RPM in the first 5 months. Median duration of program participation was 36 (31, 40) days. Eight patients (40%) experienced an unplanned readmission, or an emergency department visit, half (N = 4) of which were attributed to AKI and related circumstances. Of the 9 postgraduation survey respondents, all were satisfied with the RPM program and 89% would recommend RPM to other patients with similar health conditions.

Limitations

Acute kidney injury RPM was made possible by the existing infrastructure in our integrated health system and the robust resources available in the Mayo Clinic Center for Digital Health. Such infrastructure may not be universally available which could limit scale and generalizability of such a program.

Conclusions

Remote patient monitoring can offer a unique opportunity to bridge the care transition from hospital to home and increase access to quality care for the AKI survivors.

Implementation and evaluation of sepsis surveillance and decision support in medical ICU and emergency department

OBJECTIVE

To improve the timely diagnosis and treatment of sepsis many institutions implemented automated sepsis alerts. Poor specificity, time delays, and a lack of actionable information lead to limited adoption by bedside clinicians and no change in practice or clinical outcomes. We aimed to compare sepsis care compliance before and after a multi-year implementation of a sepsis surveillance coupled with decision support in a tertiary care center.

DESIGN

Single center before and after study.

SETTING

Large academic Medical Intensive Care Unit (MICU) and Emergency Department (ED).

POPULATION

Patients 18 years of age or older admitted to *** Hospital MICU and ED from 09/4/2011 to 05/01/2018 with severe sepsis or septic shock.

INTERVENTIONS

Electronic medical record-based sepsis surveillance system augmented by clinical decision support and completion feedback.

MEASUREMENTS AND MAIN RESULTS

There were 1950 patients admitted to the MICU with the diagnosis of severe sepsis or septic shock during the study period. The baseline characteristics were similar before (N = 854) and after (N = 1096) implementation of sepsis surveillance. The performance of the alert was modest with a sensitivity of 79.9%, specificity of 76.9%, positive predictive value (PPV) 27.9%, and negative predictive value (NPV) 97.2%. There were 3424 unique alerts and 1131 confirmed sepsis patients after the sniffer implementation. During the study period average care bundle compliance was higher; however after taking into account improvements in compliance leading up to the intervention, there was no association between intervention and improved care bundle compliance (Odds ratio: 1.16; 95% CI: 0.71 to 1.89; p-value 0.554). Similarly, the intervention was not associated with improvement in hospital mortality (Odds ratio: 1.55; 95% CI: 0.95 to 2.52; p-value: 0.078).

CONCLUSIONS

A sepsis surveillance system incorporating decision support or completion feedback was not associated with improved sepsis care and patient outcomes.

Effect of plasma exchange on antifactor Xa activity of enoxaparin and serum levetiracetam levels

PURPOSE

The effect of therapeutic plasma exchange (TPE) on antifactor Xa activity in a patient treated with enoxaparin and levetiracetam is reported.

SUMMARY

A 52-year-old woman was treated with levetiracetam and prophylactic enoxaparin while receiving TPE to manage respiratory failure due to anti-MDA5 antibody-associated interstitial lung disease (ILD) with dermatomyositis. Due to a scant amount of evidence regarding the management of these medications in TPE, therapeutic monitoring principles were used to assess the effect TPE had on these medications. A pre-TPE antifactor Xa activity level and levetiracetam serum assay, a post-TPE antifactor Xa activity level and levetiracetam serum assay, levetiracetam serum assays at 1 and 6 hours after the patient received her next dose, and a levetiracetam assay of the waste plasma from the TPE were collected for therapeutic drug monitoring and pharmacokinetic calculations. Utilizing standard population pharmacokinetic data, the expected antifactor Xa activity without TPE was 0.14 IU/mL. This concentration was significantly higher than the undetectable concentration (<0.1 IU/mL) that was drawn immediately after TPE, suggesting significant removal of antifactor Xa activity. The measured levetiracetam level did not significantly differ from the expected post-TPE levetiracetam level that was calculated using patient-specific pharmacokinetic data.

CONCLUSION

In a patient receiving TPE to manage anti-MDA5 antibody ILD associated with dermatomyositis and a prior seizure, TPE significantly altered enoxaparin antifactor Xa activity as evidenced by the undetectable antifactor Xa activity level drawn after TPE. Alternatively, TPE had a minimal effect on the clearance of levetiracetam as evidenced by the post-TPE level and fraction elimination of only 5% of total body stores.

Severe Babesia microti infection presenting as multiorgan failure in an immunocompetent host

A previously healthy 67-year-old farmer presented to an outside hospital after a 2-week history of non-specific respiratory symptoms. A certain diagnosis was not initially apparent, and the patient was discharged home on a regimen for presumed chronic obstructive pulmonary disease exacerbation. He re-presented to the emergency department with shock and hypoxaemic respiratory failure requiring prompt intubation and fluid resuscitation. He was then transferred to our institution due to multiorgan failure. On arrival, the patient demonstrated refractory shock and worsening acute kidney injury, severe anaemia and thrombocytopaenia. The peripheral smear revealed absence of microangiopathic haemolytic anaemia. A closer review of the smear displayed red blood cell inclusion bodies consistent with babesiosis. The patient was started on clindamycin and loaded with intravenous quinidine, and subsequently transitioned to oral quinine. A red cell exchange transfusion was pursued with improvement of the parasite load. The patient was discharged home on clindamycin/quinine and scheduled for outpatient intermittent haemodialysis.

Chylothorax as a Risk Factor for Thrombosis in Adults: A Proof-of-Concept Study

BACKGROUND

Postoperative chylothorax in children is associated with an increased risk of vascular thrombosis, hypothesized to be from loss of antithrombin into chylous fluid resulting in a hypercoagulable state. In adults, an increased thrombotic risk with chylothorax has not been described. Adults undergoing Ivor-Lewis esophagogastrectomy have two strong thrombotic risk factors-active malignancy and postoperative state-allowing for relative homogeneity in baseline thrombotic risk; therefore, we studied the association of chylothorax with thrombosis in this population.

METHODS

We performed a single-center retrospective cohort study at a tertiary care academic center. Patients included adults undergoing Ivor-Lewis esophagogastrectomy between January 1, 2006, and December 31, 2012. We collected demographics, pleural fluid characteristics, and relevant imaging within 30 days after the operation. Using nominal logistic regression, we studied the effects of chylothorax, age, sex, body mass index, American Society of Anesthesiologists Physical Status Classification, operative duration, and hospital length of stay on the incidence of postoperative thrombosis.

RESULTS

We identified 608 patients who underwent Ivor-Lewis esophagogastrectomy. Of these, 524 (86.2%) had no pleural fluid analysis, 48 (7.9%) had nonchylous effusions, and 36 (5.9%) had chylothoraces, with incident acute vascular thrombosis within 30 days postoperatively occurring in 22 of 524 (4.2%), 2 of 48 (4.2%), and 8 of 36 (22.2%), respectively (p = 0.001). In multivariate analyses, after adjusting for the above factors, chylothorax was associated with significantly higher odds of any vascular thrombosis (odds ratio, 5.46; p = 0.0013) and deep venous thrombosis/pulmonary embolism (odds ratio, 6.76; p = 0.0016).

CONCLUSIONS

Chylothorax is associated with a significantly higher incidence of vascular thrombosis in adults undergoing Ivor-Lewis esophagogastrectomy. Vascular thrombosis was associated with a significantly higher 90-day mortality rate.

Can a Novel ICU Data Display Positively Affect Patient Outcomes and Save Lives?

The aim of this study was to quantify the impact of ProCCESs AWARE, Ambient Clinical Analytics, Rochester, MN, a novel acute care electronic medical record interface, on a range of care process and patient health outcome metrics in intensive care units (ICUs). ProCCESs AWARE is a novel acute care EMR interface that contains built-in tools for error prevention, practice surveillance, decision support and reporting. We compared outcomes before and after AWARE implementation using a prospective cohort and a historical control. The study population included all critically ill adult patients (over 18 years old) admitted to four ICUs at Mayo Clinic, Rochester, MN, who stayed in hospital at least 24 h. The pre-AWARE cohort included 983 patients from 2010, and the post-AWARE cohort included 856 patients from 2014. We analyzed patient health outcomes, care process quality, and hospital charges. After adjusting for patient acuity and baseline demographics, overall in-hospital and ICU mortality odds ratios associated with AWARE intervention were 0.45 (95% confidence interval 0.30 to 0.70) and 0.38 (0.22, 0.66). ICU length of stay decreased by about 50%, hospital length of stay by 37%, and total charges for hospital stay by 30% in post AWARE cohort (by $43,745 after adjusting for patient acuity and demographics). Better organization of information in the ICU with systems like AWARE has the potential to improve important patient outcomes, such as mortality and length of stay, resulting in reductions in costs of care.

Impact of Telemedicine Monitoring of Community ICUs on Interhospital Transfers

OBJECTIVES

To study the effects of tele-ICU monitoring on interhospital transfers from community-based ICUs to the quaternary care hospital at Mayo Clinic, Rochester, MN.

DESIGN

This is a retrospective review of data on interhospital transfers comparing trends prior to tele-ICU implementation to those following implementation.

SETTING

Tele-ICU programs are increasingly utilized to fill resource gaps in caring for critically ill patients. How such programs impact population and bed management within a healthcare system are not known. Mayo Clinic serves as quaternary referral care center for hospitals in the region within the Mayo Clinic Health System. In August 2013, we implemented tele-ICU monitoring at six Mayo Clinic Health System hospital ICUs.

SUBJECTS

All adult ICU admissions during the study period (preimplementation phase: January 1, 2012, to December 31, 2012; and postimplementation phase: January 1, 2014, to December 31, 2014) in any of the six specified community ICUs were included in the study.

MEASUREMENTS AND MAIN RESULTS

Interhospital transfers significantly increased post institution of tele-ICU (p = 0.040) and was attributed primarily to transfer from less specialized ICUs (p = 0.037) as compared with more resource-intensive ICUs (p = 0.88). However, for such patient transfers, there were no significant differences before and after severity of illness scores, ICU mortality, or inhospital mortality.

CONCLUSION

In a regional healthcare system, implementation of a tele-ICU program is associated with an increase in interhospital transfers from less resourced ICUs to the referral center, a trend that is not readily explained by increased severity of illness.

Perceived safety and efficacy of neuromuscular blockers for acute respiratory distress syndrome among medical intensive care unit practitioners: A multicenter survey

PURPOSE

Neuromuscular blocking agents (NMBAs) are frequently used in patients with acute respiratory distress syndrome (ARDS). The purpose of this survey is to describe providers' knowledge and perceived efficacy and safety of NMBAs in patients with ARDS.

MATERIALS AND METHODS

We performed a prospective, multicenter survey of medical intensive care unit intensivists, fellows, nurse practitioners (NPs), physician's assistants (PAs), and pharmacists at 5 tertiary care centers between July 2012 and May 2013.

RESULTS

A total of 335 surveys were sent to providers, with a 47% response rate. Ninety-eight percent of providers correctly identified that NMBAs lack anxiolytic and analgesic properties. The effect of end-organ damage on NMBA clearance was less commonly identified by NPs/PAs for both hepatic (P=.0077) and renal (P=.0272) dysfunction compared with physicians. More NP/PAs identified the association of consciousness with the use of NMBAs than physicians (P=.047). Forty-two percent of prescribers reported always or frequently using continuous-infusion NMBAs in patients with severe ARDS, with 89% initiating NMBAs because of ventilator dyssynchrony. Prescribers perceived continuous NMBAs to be more effective than inhaled prostaglandins (74% vs 56%) in severe ARDS but less safe (45% vs 84%). Train of 4 was identified by 54% of prescribers as their primary method for titration.

CONCLUSION

Providers are knowledgeable about NMBAs, but educational opportunities exist. Perceptions about the efficacy and safety of NMBAs varied among prescribers, and inconsistencies existed in the prioritization of management strategies for ARDS.

Empyema management: A cohort study evaluating antimicrobial therapy

OBJECTIVES

Empyemas require aggressive antimicrobial and surgical management. However, the specifics of antimicrobial therapy have not been studied in clinical trials. The present study examines management and outcomes among a cohort of patients with empyema cared for in a tertiary-care referral hospital over a decade.

METHODS

We retrospectively identified patients hospitalized with empyema from January 2000 through December 2010 at one institution. Patient demographics, laboratory findings, treatments, and patient outcomes were abstracted using a standard form. Data were summarized with standard descriptive statistics.

RESULTS

A total of 91 patients were identified. The predominant organisms were viridans group streptococci, which were isolated in 64% of cases with cultures. The median length of hospitalization was 9 days. Length of antimicrobial therapy from time of source control was variable, with a median (interquartile range) duration of 27 (15-31) days. Of note, longer courses of parenteral, but not oral, therapy were associated with fewer cases of clinical failure.

CONCLUSIONS

This descriptive analysis demonstrated a higher rate of viridans group streptococci than expected. Three weeks of therapy was generally adequate and prevented clinical failure, but further study is needed with a much larger cohort to better define the optimal drug regimen, route, and duration of antimicrobial therapy for empyema.

Patients With Fibrotic Interstitial Lung Disease Hospitalized for Acute Respiratory Worsening: A Large Cohort Analysis

BACKGROUND

Acute respiratory worsening (ARW) requiring hospitalization in patients with fibrotic interstitial lung disease (f-ILD) is common. Little is known about the frequency and implications of ARW in IPF and non-IPF ILD patients hospitalized for acute exacerbation (AE) vs known causes of ARW.

METHODS

All consecutive patients with f-ILD hospitalized with ARW at our institution from 2000 to 2014 were reviewed. ARW was defined as any worsening of respiratory symptoms with new or worsened hypoxemia or hypercapnia within 30 days of admission. Suspected AE was defined using modified 2007 American Thoracic Society/European Respiratory Society criteria. Known causes of ARW were reviewed and collated along with in-hospital and all-cause mortality postdischarge.

RESULTS

A total of 220 patients (100 with IPF and 120 non-IPF) composed 311 admissions for ARW. Suspected AE (SAE) comprised 52% of ARW admissions, followed by infection (20%), and subacute progression of disease (15%). In-hospital mortality was similar in patients with IPF vs patients without (55 vs 45%, P = .18), but worse in suspected AE admission types (OR, 3.1 [1.9-5.14]). One-year survival after last ARW admission for the whole cohort was 22%, despite only 27% of patients presenting with baseline oxygen requirement at admission and a mean admission Charlson Comorbidity Index score of 5.4 (expected 1-year survival, 89%). Survival after discharge was similar between SAE and secondary ARW admission types in both IPF and non-IPF patients.

CONCLUSIONS

Among patients with f-ILD, hospitalization for ARW appears associated with significant in-hospital and postdischarge mortality regardless of underlying fibrotic lung disease or non-AE cause of acute respiratory decline.

Intensive Care Nurses' Knowledge About Use of Neuromuscular Blocking Agents in Patients With Respiratory Failure

BACKGROUND

The recent increase in use of neuromuscular blocking agents (NMBAs) in patients with acute respiratory distress syndrome is set against a backdrop of concerns about harm associated with use of these high-risk drugs. Bedside nurses play a pivotal role in the safe and effective use of these agents.

OBJECTIVE

To describe critical care nurses' knowledge of the therapeutic properties, adverse effects, and monitoring parameters associated with NMBAs.

METHODS

A prospective, multicenter survey of medical intensive care unit nurses between July 2012 and May 2013. The web-based survey instrument was designed, pretested, and administered under the direction of a multidisciplinary group of individuals.

RESULTS

Responses from 160 nurses (22% of eligible nurses) were analyzed. Most respondents were able to identify NMBAs correctly as nonanalgesic (93%) and nonanxiolytic (83%). The perceived durations of action of NMBAs varied widely, and few nurses were familiar with patient-specific considerations related to drug elimination. Most (70%) recognized the independent associations between NMBAs and footdrop, muscle breakdown, and corneal ulceration. Pressure ulcers and a history of neuromuscular disease were the characteristics of patients perceived to most heighten the risk of NMBA use.

CONCLUSIONS

Critical care nurses are knowledgeable about the importance of concurrent analgesia and sedation during use of NMBAs. Routes of elimination, duration of action, and adverse effects were less commonly known and represent areas for focused education and quality improvement surrounding use of NMBAs in the intensive care unit.

Pulmonary embolus diagnosed by endobronchial ultrasound

Endobronchial ultrasound (EBUS) imaging is commonly used to evaluate and aid in biopsy of mediastinal lymph nodes. Pulmonary arteries are readily viewable with this type of imaging modality. We present a case report of a pulmonary embolism (PE) diagnosed by EBUS. Our patient had no smoking history and presented with respiratory and constitutional symptoms, urinary retention, and leg weakness suspicious for malignancy with metastasis to spine. Chest computed tomography (CT) was suggestive of lung carcinoma and specifically showed no PE. EBUS with TBNA was requested for tissue diagnosis. A mobile filling defect consistent with a PE was observed and reported to primary team. Follow-up chest CT showed an acute PE which confirmed the diagnosis originally made by EBUS. Bronchoscopists should be aware of potential to diagnose a PE while performing EBUS. Additionally, there may be a role in using EBUS specifically to diagnose a PE in the right patient population.

Tension chylothorax following pneumonectomy

Post-pneumonectomy chylothorax is an uncommon complication following surgery, with an estimated incidence of less than 0.7%. Post-pneumonectomy tension chylothorax, where rapid accumulation of chyle in the post-pneumonectomy space results in hemodynamic compromise, is exceedingly rare, with just 7 cases previously reported. All prior cases of tension chylothorax were managed operatively with decompressive chest tube placement followed by open thoracic duct repair. Our case is the first reported tension chylothorax to be managed conservatively by thoracostomy drainage coupled with a period of parenteral nutrition followed by a medium chain triglyceride-restricted diet.

Idiopathic pulmonary fibrosis: evolving concepts

Idiopathic pulmonary fibrosis (IPF) occurs predominantly in middle-aged and older adults and accounts for 20% to 30% of interstitial lung diseases. It is usually progressive, resulting in respiratory failure and death. Diagnostic criteria for IPF have evolved over the years, and IPF is currently defined as a disease characterized by the histopathologic pattern of usual interstitial pneumonia occurring in the absence of an identifiable cause of lung injury. Understanding of the pathogenesis of IPF has shifted away from chronic inflammation and toward dysregulated fibroproliferative repair in response to alveolar epithelial injury. Idiopathic pulmonary fibrosis is likely a heterogeneous disorder caused by various interactions between genetic components and environmental exposures. High-resolution computed tomography can be diagnostic in the presence of typical findings such as bilateral reticular opacities associated with traction bronchiectasis/bronchiolectasis in a predominantly basal and subpleural distribution, along with subpleural honeycombing. In other circumstances, a surgical lung biopsy may be needed. The clinical course of IPF can be unpredictable and may be punctuated by acute deteriorations (acute exacerbation). Although progress continues in unraveling the mechanisms of IPF, effective therapy has remained elusive. Thus, clinicians and patients need to reach informed decisions regarding management options including lung transplant. The findings in this review were based on a literature search of PubMed using the search terms idiopathic pulmonary fibrosis and usual interstitial pneumonia, limited to human studies in the English language published from January 1, 2000, through December 31, 2013, and supplemented by key references published before the year 2000.

Frequency and implication of autoimmune serologies in idiopathic pulmonary fibrosis

OBJECTIVE

To assess the frequency and clinical implications of positive autoimmune serologies in patients with biopsy-confirmed idiopathic pulmonary fibrosis (IPF).

PATIENTS AND METHODS

We reviewed the records of patients at our institution with biopsy-confirmed usual interstitial pneumonia (UIP) from January 1, 1995, through December 31, 2010, for frequency and distribution of autoimmune serologies. Patients with IPF with and without positive serologies were compared.

RESULTS

Three hundred eighty-nine consecutive patients with biopsy-confirmed IPF underwent serologic testing, with positive serologic test results being found in 112 (29%). Of 2051 individual screening serologic tests performed, results of 163 tests were positive (8%), with antinuclear antibody being the most frequent (47%). There was no difference in age at biopsy (P=.21), gender (P=.21), or presenting radiologic features between those with or without positive serology. More frequent use of immunosuppressive treatment (P=.02) was noted in those with positive serology. No survival difference was observed (log-rank; P=.43). Median follow-up for the whole cohort was 43.5 months.

CONCLUSION

Positive autoimmune serology may occur in as much as one-third of the patients with biopsy-confirmed IPF with no associated clinical implication or survival advantage. Systematic use of autoimmune laboratory panels in patients without clinical features of connective tissue disease should be reconsidered in patients with suspected UIP on chest computed tomography scan or confirmed UIP on biopsy.

Advances in the management of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a common form of interstitial lung disease and usually results in progressive respiratory insufficiency and death. Steady progress has been made in understanding the pathogenesis of IPF and multiple clinical trials are ongoing, but effective therapy remains elusive.

Imatinib treatment for idiopathic pulmonary fibrosis: Randomized placebo-controlled trial results

RATIONALE

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with no known efficacious therapy. Imatinib is a tyrosine kinase inhibitor with potential efficacy to treat fibrotic lung disease.

OBJECTIVES

To investigate the safety and clinical effects of imatinib in patients with IPF.

METHODS

We studied 119 patients in an investigator-initiated, multicenter, multinational, double-blind clinical trial to receive imatinib or placebo for 96 weeks.

MEASUREMENTS AND MAIN RESULTS

Over 96 weeks of follow-up, imatinib did not differ significantly from placebo (log rank P = 0.89) for the primary endpoint defined as time to disease progression (10% decline in percent predicted FVC from baseline) or time to death. There was no effect of imatinib therapy on change in FVC at 48, 72, or 96 weeks (P > or = 0.39 at all time points) or change in diffusing capacity of carbon monoxide at 48, 72, or 96 weeks (P > or = 0.26 at all time points). Change in resting Pa(O(2)) favored imatinib therapy at 48 weeks (P = 0.005) but not at 96 weeks (P = 0.074). During the 96-week trial there were 8 deaths in the imatinib group and 10 deaths in the placebo group (log rank test P = 0.64). Thirty-five (29%) patients discontinued the study without reaching the primary endpoint (imatinib, 32%; placebo, 27%; P = 0.51). Serious adverse events (SAEs) were not more common in the imatinib group (imatinib, 18 SAEs in 17 patients; placebo, 19 SAEs in 18 patients).

CONCLUSIONS

In a randomized, placebo-controlled trial of patients with mild to moderate IPF followed for 96 weeks, imatinib did not affect survival or lung function. Clinical trial registered with www.clinicaltrials.gov (NCT00131274).

Incidence, prevalence, and clinical course of idiopathic pulmonary fibrosis: a population-based study

BACKGROUND

Limited data exist regarding the population-based epidemiology of idiopathic pulmonary fibrosis (IPF). The objective of the study was to describe the trends in the incidence, prevalence, and clinical course of IPF in the community.

METHODS

We conducted a population-based study of adult patients with IPF in Olmsted County, Minnesota, from 1997 to 2005. Two methods were used to identify IPF cases, as defined by the 2002 American Thoracic Society/European Respiratory Society consensus statement: (1) usual interstitial pneumonia (UIP) on a surgical lung biopsy specimen or a definite UIP pattern on a high-resolution CT image (narrow criteria) and (2) UIP on a surgical lung biopsy specimen or a definite or possible UIP pattern on CT image (broad criteria).

RESULTS

Of 596 patients screened for the possibility of pulmonary disease or pulmonary fibrosis over 9 years of follow-up, 47 cases had IPF. Of these, 24 met the narrow criteria. The age- and sex-adjusted incidence was 8.8/100,000 and 17.4/100,000 person-years, for narrow and broad criteria, respectively. The age-adjusted incidence was higher in men than in women, and among patients aged 70-79 years. During the study period, the incidence of IPF decreased (P < .001). On December 31, 2005, the age- and sex-adjusted prevalence was 27.9/100,000 and 63/100,000 persons by narrow and broad criteria, respectively. Thirty-seven patients experienced a total of 53 respiratory exacerbations (26 IPF related, 27 non-IPF related), and 34 (72%) patients died. The primary cause of death was IPF related in 16 (47%) patients. Median survival for narrow-criteria and broad-criteria incidence cases was 3.5 and 4.4 years, respectively.

CONCLUSIONS

The incidence of IPF in Olmsted County decreased over the study period. Nonprimary IPF respiratory exacerbations are as frequent as primary IPF respiratory exacerbations and an important cause of death.

Pleural fluid characteristics of chylothorax

OBJECTIVE

To determine the biochemical parameters of chylous pleural fluids and better inform current clinical practice in the diagnosis of chylothorax.

PATIENTS AND METHODS

We retrospectively reviewed 74 patients with chylothorax (defined by the presence of chylomicrons) who underwent evaluation during a 10-year period from January 1, 1997, through December 31, 2006. The biochemical parameters and appearance of the fluid assessed during diagnostic evaluation were analyzed.

RESULTS

The study consisted of 37 men (50%) and 37 women (50%), with a median age of 61.5 years (range, 20-93 years). Chylothorax was caused by surgical procedures in 51%. The chylous pleural fluid appeared milky in only 44%. Pleural effusion was exudative in 64 patients (86%) and transudative in 10 patients (14%). However, pleural fluid protein and lactate dehydrogenase levels varied widely. Transudative chylothorax was present in all 4 patients with cirrhosis but was also seen with other causes. The mean +/- SD triglyceride level was 728+/-797 mg/dL, and the mean +/- SD cholesterol value was 66+/-30 mg/dL. The pleural fluid triglyceride value was less than 110 mg/dL in 10 patients (14%) with chylothorax, 2 of whom had a triglyceride value lower than 50 mg/dL.

CONCLUSION

Chylothoraces may present with variable pleural fluid appearance and biochemical characteristics. Nonmilky appearance is common. Chylous effusions can be transudative, most commonly in patients with cirrhosis. Traditional triglyceride cutoff values used in excluding the presence of chylothorax may miss the diagnosis in fasting patients, particularly in the postoperative state.

Pleural fluid characteristics of chylothorax

OBJECTIVE

To determine the biochemical parameters of chylous pleural fluids and better inform current clinical practice in the diagnosis of chylothorax.

PATIENTS AND METHODS

We retrospectively reviewed 74 patients with chylothorax (defined by the presence of chylomicrons) who underwent evaluation during a 10-year period from January 1, 1997, through December 31, 2006. The biochemical parameters and appearance of the fluid assessed during diagnostic evaluation were analyzed.

RESULTS

The study consisted of 37 men (50%) and 37 women (50%), with a median age of 61.5 years (range, 20-93 years). Chylothorax was caused by surgical procedures in 51%. The chylous pleural fluid appeared milky in only 44%. Pleural effusion was exudative in 64 patients (86%) and transudative in 10 patients (14%). However, pleural fluid protein and lactate dehydrogenase levels varied widely. Transudative chylothorax was present in all 4 patients with cirrhosis but was also seen with other causes. The mean +/- SD triglyceride level was 728+/-797 mg/dL, and the mean +/- SD cholesterol value was 66+/-30 mg/dL. The pleural fluid triglyceride value was less than 110 mg/dL in 10 patients (14%) with chylothorax, 2 of whom had a triglyceride value lower than 50 mg/dL.

CONCLUSION

Chylothoraces may present with variable pleural fluid appearance and biochemical characteristics. Nonmilky appearance is common. Chylous effusions can be transudative, most commonly in patients with cirrhosis. Traditional triglyceride cutoff values used in excluding the presence of chylothorax may miss the diagnosis in fasting patients, particularly in the postoperative state.

Reducing iatrogenic risk in thoracentesis: establishing best practice via experiential training in a zero-risk environment

BACKGROUND

We studied the reasons why patients undergoing thoracenteses performed in our outpatient pulmonary clinic had a higher frequency of iatrogenic pneumothorax compared to that in the concurrent radiology practice in our institution, which utilizes ultrasound guidance. We reviewed our practice model and implemented a unique experiential training paradigm in a zero-risk simulation environment to improve efficacy, timeliness, service orientation, and safety.

METHODS

We retrospectively determined the rate of clinically significant pneumothoraces in our practice (phase I, July 1, 2001, to June 30, 2002). The training system redesign included the following: (1) a designated group of pulmonologist instructors dedicated to treating pleural disease and reducing the number of iatrogenic complications; (2) the use of ultrasound image guidance for all thoracenteses; and (3) structured proficiency and competency standards for proceduralists. Postintervention (phase II) data were prospectively collected (January 2005 to December 2006) and compared with our baseline data.

RESULTS

The baseline rate of pneumothorax was 8.6% (5 of 58 patients) in our pulmonary practice. Following intervention (phase II), the rate of pneumothorax declined to 1.1% (p = 0.0034). During phase II, the number of thoracenteses performed increased (186 vs 58 per year, respectively; p < 0.05). The iatrogenic pneumothorax rate was stable in the 2 years following intervention (2005, 0.7% [1 of 137 pneumothoraces]; 2006, 1.3% [3 of 226 pneumothoraces]; p > 0.9). Postintervention complications included procedure-related pain (n = 19), cough (n = 4), and hypotension (n = 10).

CONCLUSIONS

An improvement program that included simulation, ultrasound guidance, competency testing, and performance feedback reduced iatrogenic risk to patients. We recommend application of this process to procedural practices.

The accuracy of natriuretic peptides (brain natriuretic peptide and N-terminal pro-brain natriuretic) in the differentiation between transfusion-related acute lung injury and transfusion-related circulatory overload in the critically ill

BACKGROUND

The diagnostic workup of transfusion-related acute lung injury (TRALI) requires an exclusion of transfusion-associated circulatory overload (TACO). Brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic (NT-pro-BNP) accurately diagnosed TACO in preliminary studies that did not include patients with TRALI.

STUDY DESIGN AND METHODS

In this prospective cohort study, two critical care experts blinded to serum levels of BNP and NT-pro-BNP determined the diagnosis of TRALI, TACO, and possible TRALI based on the consensus conference definitions. The accuracy of BNP and NT-pro-BNP was assessed based on the area under the receiver operating curve (AUC).

RESULTS

Of 115 patients who developed acute pulmonary edema after transfusion, 34 were identified with TRALI, 31 with possible TRALI, and 50 with TACO. Median BNP was 375 pg per mL (interquartile range [IQR], 123 to 781 pg/mL) in TRALI, 446 pg per mL (IQR, 128 to 743 pg/mL) in possible TRALI, and 559 pg per mL (IQR, 288 to 1348 pg/mL) in TACO patients (p = 0.038). The NT-pro-BNP levels among patients with TRALI, possible TRALI, and TACO differed significantly with a median value of 1559 pg per mL (IQR, 629 to 5114 pg/mL), 2349 pg/mL (IQR, 919 to 4610 pg/mL), and 5197 pg/mL (IQR, 1695 to 15,714 pg/mL; p = 0.004), respectively. The accuracy of BNP and NT-pro-BNP to diagnose TACO was moderate with an AUC of 0.63 (95% confidence interval [CI], 0.51-0.74) and 0.70 (95% CI, 0.59 to 0.80).

CONCLUSIONS

Natriuretic peptides are of limited diagnostic value in a differential diagnosis of pulmonary edema after transfusion in the critically ill patients.

Assessment of current practice in the diagnosis and therapy of idiopathic pulmonary fibrosis

BACKGROUND

The consensus statement on the Diagnosis and Therapy of Idiopathic Pulmonary Fibrosis (IPF) formulated by the American Thoracic Society/European Respiratory Society (ATS/ERS) was published in 2000. Acceptance and implementation of these guidelines have not been assessed. We surveyed the fellows of the American College of Chest Physicians (FCCP) to establish current practice patterns regarding the diagnosis and therapy of IPF.

METHODS

We electronically distributed a 32-item questionnaire to all 6443 pulmonary medicine board-certified Fellows of the American College of Chest Physicians. The response rate was 13%. Demographic characteristics were similar between respondents and non-respondents.

RESULTS

Seventy-two percent of respondents were familiar with the ATS/ERS consensus statement and 63% found it clinically useful. However, a similar number of respondents indicated that an update is needed. Bronchoscopy and surgical lung biopsy are used infrequently. Forty-five percent of pulmonary physicians advocate providing only supportive care for patients outside of clinical trials. If pharmacological therapy is recommended, prednisone (either alone or in combination with azathioprine) or off-label agents are preferentially prescribed. Despite physician awareness (79%) of clinical trials, interested patients are not consistently referred (54%). A majority of respondents (61%) felt that lung transplantation represents the only effective therapy for IPF, and 86% refer their patients to lung transplant centers.

CONCLUSIONS

There is substantial variability among pulmonary physicians in the diagnosis and management of IPF. This may, in part, reflect the current lack of effective pharmacologic therapy. Updated practice guidelines are needed for the diagnosis and therapy of IPF.

Ventilator settings and outcome of respiratory failure in chronic interstitial lung disease

BACKGROUND

While patients with interstitial lung disease (ILD) may be particularly susceptible to ventilator-induced lung injury, ventilator strategies have not been studied in this group of patients.

PURPOSES

To describe the clinical course and outcome of patients with ILD and acute respiratory failure in relation to ventilatory parameters.

METHODS

We retrospectively identified a cohort of ventilated patients with ILD who had been admitted to five ICUs at a single institution. We analyzed demographic data, pulmonary function test results, severity of illness, and the parameters of continuous ventilation for the initial 24 h after admission to the ICU. Primary outcomes were survival to hospital discharge and 1-year survival.

MAIN RESULTS

Of 94 patients with ILD, 44 (47%) survived to hospital discharge and 39 (41%) were alive at 1 year. Nonsurvivors were less likely to be postoperative, had higher severity of illness, and were ventilated at higher airway pressures and lower tidal volumes. Step changes in positive end-expiratory pressure (PEEP) of > 10 cm H(2)O were attempted in 20 patients and resulted in an increase in plateau pressure (median difference, + 16 cm H(2)O; interquartile range [IQR], 9 to 24 cm H(2)O) and a decrease in respiratory system compliance (median difference, - 0.28 mL/kg/cm H(2)O; IQR, - 0.43 to - 0.13 mL/kg/cm H(2)O). The Cox proportional hazards model revealed that high PEEP (hazard ratio, 4.72; 95% confidence interval [CI], 2.06 to 11.15), acute physiology and chronic health evaluation (APACHE) III score predicted mortality (hazard ratio 1.33; 95% CI, 1.18 to 1.50), age (hazard ratio, 1.03; 95% CI, 1 to 1.05), and low Pao(2)/fraction of inspired oxygen ratio (hazard ratio, 0.96; 95% CI, 0.92 to 0.99) to be independent determinants of survival.

CONCLUSION

Both severity of illness and high PEEP settings are associated with the decreased survival of patients with ILD who are receiving mechanical ventilation.

The utility of fluorodeoxyglucose positron emission tomography in the evaluation of carcinoid tumors presenting as pulmonary nodules

BACKGROUND

Fluorodeoxyglucose positron emission tomography (FDG-PET) is sensitive for detection of neoplastic solitary pulmonary nodules but may have decreased sensitivity for detection of carcinoid tumors. Our purpose was to determine the sensitivity of FDG-PET to detect pulmonary carcinoid tumors.

METHODS

We performed a retrospective review of our institutional results regarding FDG-PET in the setting of thoracic carcinoid neoplasms. We identified 16 patients with a pathologic diagnosis of bronchial carcinoid who had an antecedent FDG-PET (from 2000 to 2004). All patients but one presented with pulmonary nodule(s).

RESULTS

Sixteen patients had a diagnosis of carcinoid tumor, typical in 11 patients and atypical in 5 patients. The mean greatest pathologic dimension was 2.08 cm (range, 1.0 to 8.3 cm). Overall positron emission tomography (PET) sensitivity was 75% (12 true-positive and 4 false-negative results). The mean (+/- SD) size of carcinoids with false-negative PET results was not significantly different from carcinoids with true-positive results (1.6 +/- 0.81 cm and 2.35 +/- 1.87 cm, p = 0.54). Fifteen of 16 patients were staged pathologically, and positive nodes were found in 2 of these patients. PET lymph node staging agreed with pathologic staging in one stage 4 patient with positive lymph nodes and distant metastasis, but PET results were false negative in the other patient who had N2 with micrometastatic disease; stage IIIA.

CONCLUSIONS

FDG-PET imaging is useful for evaluation of typical and atypical thoracic carcinoid tumors. Although overall PET sensitivity for detection of carcinoid tumors is somewhat reduced as compared to non-small cell lung cancer, it is much higher than prior reports suggest.

Focal Organizing Pneumonia on Surgical Lung Biopsy

BACKGROUND

Organizing pneumonia (OP) is a histologic pattern that is morphologically distinctive but nonspecific and can be seen in diverse clinical settings. Focal OP has been described as a discrete form of OP, but relatively little is known regarding this clinicopathologic entity.

METHODS

We sought to clarify the clinicoradiologic presentation, underlying causes, and outcomes associated with focal OP by retrospectively reviewing 26 consecutive cases diagnosed by surgical lung biopsy over an 8-year period from January 1, 1997, to December 31, 2004.

RESULTS

All patients presented with an unifocal opacity detected on chest radiography (20 patients) or CT scans (6 patients). At the time of presentation, 10 patients (38%) had symptoms, including cough, shortness of breath, or chest pain; 16 patients were asymptomatic. Contrast-enhancement CT scanning or positron emission tomography (PET) scan was performed in 11 patients, and the results were positive in all. Surgical procedures included wedge resection in 21 patients (81%), segmentectomy in 3 patients (11%), and lobectomy in 2 patients (8%). Three case of focal OP (12%) were related to infections, but the remaining cases were cryptogenic. Follow-up over a median interval of 11 months (range, 1 to 71 months) yielded no recurrence of OP.

CONCLUSIONS

The radiologic features of focal OP are often indistinguishable from those of lung cancer, and include positivity on contrast-enhancement CT scan and PET scan. Most cases of focal OP are cryptogenic, and infection is identified in a minority of cases. Surgical resection alone appears to suffice in the management of cryptogenic focal OP.

Diagnosis of interstitial lung diseases

Interstitial lung diseases (ILDs), a broad heterogeneous group of parenchymal lung disorders, can be classified into those with known and unknown causes. The definitions and diagnostic criteria for several major forms of ILDs have been revised in recent years. Although well over 100 distinct entities of ILDs are recognized, a limited number of disorders, including idiopathic pulmonary fibrosis, sarcoidosis, and connective tissue disease-related ILDs, account for most ILDs encountered clinically. In evaluating patients with suspected ILD, the clinician should confirm the presence of the disease and then try to determine its underlying cause or recognized clinicopathologic syndrome. Clues from the medical history along with the clinical context and radiologic findings provide the initial basis for prioritizing diagnostic possibilities for a patient with ILD. High-resolution computed tomography of the chest has become an invaluable tool in the diagnostic process. A confident diagnosis can sometimes be made on the basis of high-resolution computed tomography and clinical context. Serologic testing can be helpful in selected cases. Histopathologic findings procured through bronchoscopic or surgical lung biopsy are often needed in deriving a specific diagnosis. An accurate prognosis and optimal treatment strategy for patients with ILDs depend on an accurate diagnosis, one guided by recent advances in our understanding of the causes and pathogenetic mechanisms of ILDs.

Treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a relentlessly progressive lung disease in most cases, and effective treatment is still lacking. This review examines the current status of treatment options and complexities in the management of patients with IPF. Although optimal therapy for IPF has not been identified, ongoing research efforts warrant reason for optimism. Current management of IPF includes not only judicious use of available pharmacological agents tailored to individual circumstances but also patient education through realistic assessment of prognosis, discussion of pros and cons of pharmacotherapy, early consideration of lung transplantation when applicable, treatment of complications, supportive care, and encouragement to participate in clinical trials.

Organizing pneumonia in patients with hematologic malignancies: A steroid-responsive lesion

BACKGROUND

Organizing pneumonia (OP) is a distinct histopathologic lesion that occurs in a variety of clinical contexts. There have been occasional reports of OP occurring in patients with hematologic malignancies.

STUDY OBJECTIVES

To examine the association of OP with hematologic malignancies and to assess the clinical course of affected patients.

DESIGN

A retrospective review of our institutional experience of unexplained OP developing in patients with hematologic malignancies.

SETTING

Tertiary care, referral medical center.

PATIENTS

We identified 6 patients with a verified histopathologic diagnosis of OP and antecedent or concomitant diagnosis of a hematologic malignancy from the Mayo Clinic database (1995-2003). Clinical, radiologic, and outcome data were abstracted from records.

RESULTS

Underlying hematologic disorders included lymphoma (2), acute leukemia (2), cutaneous T-cell lymphoma (1), and myelodysplastic syndrome (1). OP was diagnosed by surgical lung biopsy in 4 and bronchoscopic biopsy in 2. Four of the 6 patients had previously been exposed to chemotherapeutic agents, two had not. Three of the 6 patients had bone marrow transplantation prior to development of OP. Five patients were treated with prednisone and all experienced symptomatic improvement with documented radiologic resolution in 4. One patient experienced symptomatic and radiologic resolution with observation alone. Three patients ultimately died from complications of their underlying hematologic disorder and 1 patient died of unknown causes. Two patients were alive without respiratory complaints more than 1 year after lung biopsy.

CONCLUSIONS

OP occurs in patients with underlying hematologic malignancies who may or may not have been treated with chemotherapy and responds favorably to corticosteroid therapy.

B-type natriuretic peptide in the assessment of acute lung injury and cardiogenic pulmonary edema*

OBJECTIVE

The role of plasma B-type natriuretic peptide (BNP) in critically ill patients with acute pulmonary edema is controversial. We postulated that a low BNP level would exclude cardiac dysfunction as the principal cause of pulmonary edema and therefore help in the diagnosis of acute lung injury.

DESIGN

A retrospective derivation cohort was followed by a prospective validation cohort of consecutive patients with acute pulmonary edema admitted to three intensive care units. BNP was measured within 24 hrs from onset. Critical care experts blinded to BNP results integrated clinical data with the course of disease and response to therapy and served as the reference standard.

SETTING

Three intensive care units at the tertiary center.

PATIENTS

Consecutive critically ill patients with acute pulmonary edema.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

In a derivation cohort of 84 patients, a BNP threshold of <or=250 pg/mL had a specificity of 87% and sensitivity of 48% for the diagnosis of acute lung injury. High specificity of BNP (90%, likelihood ratio of 3.9) was confirmed in a validation cohort of 120 consecutive patients, 52 (43%) of whom had acute lung injury. Notably, 32% of patients with acute lung injury had concomitant cardiac dysfunction. The median time from the onset of pulmonary edema to BNP testing was 3 hrs. The accuracy of BNP (area under receiver operator curve, 0.71) was comparable with pulmonary artery occlusion pressure (area under receiver operator curve, 0.66) and superior to ejection fraction (area under receiver operator curve, 0.60) in subgroups of patients in whom these tests were performed. The accuracy of BNP improved when patients with renal insufficiency were excluded (area under receiver operator curve, 0.82).

CONCLUSION

When measured early after the onset of acute pulmonary edema, a BNP level of <250 pg/mL supports the diagnosis of acute lung injury. The high rate of cardiac and renal dysfunction in critically ill patients limits the discriminative role of BNP. No level of BNP could completely exclude cardiac dysfunction.

Alkaptonuria diagnosed by flexible bronchoscopy

A 68-year-old white man was evaluated for failure to wean from mechanical ventilation after cardiac surgery. Bronchoscopy performed prior to percutaneous dilatational tracheotomy revealed circumferential strikingly dark-colored airways, most prominent in the trachea and mainstem bronchi, extending distally into all airways with overlying desiccated black secretions. Histologic examination of bronchial mucosal biopsy samples and the desiccated secretions showed acute bronchitis and necrotic debris, respectively. This finding and the patient's history led to testing for plasma homogentisic acid, which was found to be elevated at 12.6 mug/mL, establishing the first diagnosis of alkaptonuria made using flexible bronchoscopy.

Does interstitial lung disease predispose to lung cancer?

PURPOSE OF REVIEW

This review examines the evidence for the causality and pathogenesis of lung cancer associated with interstitial lung disease.

RECENT FINDINGS

Although cigarette smoking is the leading cause of lung cancer, several other conditions either predispose to lung cancer or increase the risk of lung cancer in smokers. The evidence supports an increased risk of lung cancer due to specific fibrotic and inflammatory lung diseases (termed interstitial lung diseases), including idiopathic pulmonary fibrosis, systemic sclerosis, and certain pneumoconioses. The potential pathogenetic mechanisms indicate that recurrent injury and inflammation result in genetic alterations that predispose to lung cancer.

SUMMARY

Idiopathic pulmonary fibrosis, systemic sclerosis, and certain pneumoconioses are associated with an independent increased risk of lung cancer; however, a unifying pathogenetic mechanism to explain the causality of this association has not been described. In addition, the inconsistently reported lung cancer frequencies call attention to the need for prospective studies of good quality.