Inhaled epoprostenol for the treatment of pulmonary arterial hypertension in critically ill adults

Perioperative Management of Novel Pharmacotherapies for Heart Failure and Pulmonary Hypertension

Heart failure (HF) and pulmonary hypertension (PH) are increasingly prevalent comorbidities in patients presenting for noncardiac surgery. The unique pathophysiology and pharmacotherapies associated with these syndromes have important perioperative implications. As new medications for HF and PH emerge, it is imperative that anesthesiologists and other perioperative providers understand their mechanisms of action, pharmacokinetics, and potential adverse effects. We present an overview of the novel HF and PH pharmacotherapies and strategies for their perioperative management.

Safety and tolerability of continuous inhaled iloprost in critically ill pediatric pulmonary hypertension patients: A retrospective case series

Inhaled iloprost (iILO) has shown efficacy in treating patients with hypoxic lung disease and pulmonary hypertension, inducing selective pulmonary vasodilation and improvement in oxygenation. However, its short elimination half-life of 20-30 min necessitates frequent intermittent dosing (6-9 times per day). Thus, the administration of iILO via continuous nebulization represents an appealing method of drug delivery in the hospital setting. The objectives are: (1) describe our continuous iILO delivery methodology and safety profile in mechanically ventilated pediatric pulmonary hypertension patients; and (2) characterize the initial response of iILO in these pediatric patients currently receiving iNO. Continuous iILO was delivered and well tolerated (median 6 days; range 1-94) via tracheostomy or endotracheal tube using the Aerogen® mesh nebulizer system coupled with a Medfusion® 400 syringe pump. No adverse events or delivery malfunctions were reported. Initiation of iILO resulted in an increase in oxygen saturation from 81.4 ± 8.6 to 90.8 ± 4.1%, p < 0.05. Interestingly, prior iNO therapy for >1 day resulted in a higher response rate to iILO (as defined as a ≥ 4% increase in saturations) compared to those receiving iNO <1 day (85% vs. 50%, p = 0.06). When the use of iILO is considered, continuous delivery represents a safe, less laborious alternative and concurrent treatment with iNO should not be considered a contraindication. However, given the retrospective design and small sample size, this study does not allow the evaluation of the efficacy of continuous iILO on outcomes beyond the initial response. Thus, a prospective study designed to evaluate the efficacy of continuous iILO is necessary.

Comparison of 2 different inhaled epoprostenol dosing strategies for acute respiratory distress syndrome in critically ill adults: Weight-based vs fixed-dose administration

PURPOSE

Inhaled epoprostenol (iEPO) is a viable, temporizing option for acute respiratory distress syndrome (ARDS), although the optimal iEPO dosing strategy remains inconclusive. The purpose of this study was to evaluate oxygenation and ventilation parameters in a comparison of weight-based and fixed-dose iEPO in adult patients with moderate-to-severe ARDS.

METHODS

A retrospective cohort study was conducted at 2 academic medical centers in adult intensive care unit (ICU) patients administered either fixed-dose or weight-based iEPO for moderate-to-severe ARDS. The primary endpoint was the highest recorded change in the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO2) within 4 hours of baseline. Secondary analyses compared responder rates within 4 hours of initiation, oxygenation and ventilation parameters, in-hospital mortality rates, mechanical ventilation duration, length of stay (ICU and hospital), and tracheostomy rates between the study groups.

RESULTS

A total of 294 patients were included, n = 194 with 100 (34.0%) and 194 (66.0%) in the weight-based and fixed-dose iEPO groups, respectively. The mean (SD) change in the highest recorded PaO2/FiO2 value from baseline up to 4 hours after initiation in the fixed-dose and weight-based groups was 81.1 (106.0) and 41.0 (72.5) mm Hg, respectively (P = 0.0015). The responder rate at 4 hours after iEPO initiation was significantly higher in the fixed-dose group (69.9%) than in the weight-based group (30.1%) (P = 0.02). The only predictor of response was fixed-dose administration (odds ratio, 3.28; 95% confidence interval, 1.6-6.7; P = 0.0012). Clinical outcomes were comparable between the groups.

CONCLUSION

Fixed-dose iEPO was associated with significantly higher response rates then weight-based iEPO during the first 4 hours of therapy. Fixed-dose iEPO is a more convenient strategy than weight-based approaches.

Right ventricular failure: Current strategies and future development

Right heart failure can be defined as a clinical syndrome consisting of signs and symptoms of heart failure resulting from right ventricular dysfunction. Function is normally altered due to three mechanisms: (1) pressure overload (2) volume overload, or (3) a decrease in contractility due to ischaemia, cardiomyopathy or arrythmias. Diagnosis is based upon a combination of clinical assessment plus echocardiographic, laboratory and haemodynamic parameters, and clinical risk assessment. Treatment includes medical management, mechanical assist devices and transplantation if recovery is not observed. Distinct attention to special circumstances such as left ventricular assist device implantation should be sought. The future is moving towards new therapies, both pharmacological and device centered. Immediate diagnosis and management of RV failure, including mechanical circulatory support where needed, alongside a protocolized approach to weaning is important in successfully managing right ventricular failure.

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

Inhaled pulmonary vasodilators: a narrative review

Pulmonary hypertension (PH) is a severe disease that affects people of all ages. It can occur as an idiopathic disorder at birth or as part of a variety of cardiovascular and pulmonary disorders. Inhaled pulmonary vasodilators (IPV) can reduce pulmonary vascular resistance (PVR) and improve RV function with minimal systemic effects. IPV includes inhaled nitric oxide (iNO), inhaled aerosolized prostacyclin, or analogs, including epoprostenol, iloprost, treprostinil, and other vasodilators. In addition to pulmonary vasodilating effects, IPV can also be used to improve oxygenation, reduce inflammation, and protect cell. Off-label use of IPV is common in daily clinical practice. However, evidence supporting the inhalational administration of these medications is limited, inconclusive, and controversial regarding their safety and efficacy. We conducted a search for relevant papers published up to May 2020 in four databases: PubMed, Google Scholar, EMBASE and Web of Science. This review demonstrates that the clinical using and updated evidence of IPV. iNO is widely used in neonates, pediatrics, and adults with different cardiopulmonary diseases. The limitations of iNO include high cost, flat dose-response, risk of significant rebound PH after withdrawal, and the requirement of complex technology for monitoring. The literature suggests that inhaled aerosolized epoprostenol, iloprost, treprostinil and others such as milrinone and levosimendan may be similar to iNO. More research of IPV is needed to determine acceptable inclusion criteria, long-term outcomes, and management strategies including time, dose, and duration.

Comparison of Fixed-Dose Inhaled Epoprostenol and Inhaled Nitric Oxide for Acute Respiratory Distress Syndrome in Critically Ill Adults

PURPOSE

Several reports have demonstrated similar effects on oxygenation between inhaled epoprostenol (iEPO) compared to inhaled nitric oxide (iNO) for acute respiratory distress syndrome (ARDS). Previous studies directly comparing oxygenation and clinical outcomes between iEPO and iNO exclusively in an adult ARDS patient population utilized a weight-based dosing strategy. The purpose of this study was to compare the clinical and economic impact between iNO and fixed-dosed iEPO for ARDS in adult intensive care unit (ICU) patients.

METHODS

This retrospective cohort study was conducted at a major academic medical center between January 1, 2014, and October 31, 2018. Patients ≥18 years of age with moderate-to-severe ARDS were included. The primary end point was to compare the mean change in partial arterial oxygen pressure to fraction of inspired oxygen (Pao ₂: Fio ₂) at 4 hours from baseline between iEPO and iNO. Other secondary aims were total acquisition drug costs, in-hospital mortality, ICU and hospital length of stay, and duration of mechanical ventilation.

RESULTS

A total of 239 patients were included with 139 (58.2%) and 100 (41.8%) in the iEPO and iNO groups, respectively. The mean change in Pao ₂: Fio ₂ at 4 hours from baseline in the iEPO and iNO groups were 31.4 ± 54.6 and 32.4 ± 42.7 mm Hg, respectively (P = .88). The responder rate at 4 hours was similar between iEPO and iNO groups (64.7% and 66.0%, respectively, P = .84). Clinical outcomes including mortality, overall hospital and ICU length of stay, and mechanical ventilation duration were similar between iEPO and iNO groups. Estimated annual cost-savings realized with iEPO was USD1 074 433.

CONCLUSION

Fixed-dose iEPO was comparable to iNO in patients with moderate-to-severe ARDS for oxygenation and ventilation parameters as well as clinical outcomes. Significant cost-savings were realized with iEPO use.

Newer approaches and novel drugs for inhalational therapy for pulmonary arterial hypertension

Introduction: Pulmonary arterial hypertension (PAH) is a progressive disease characterized by remodeling of small pulmonary arteries leading to increased pulmonary arterial pressure. Existing treatments acts to normalize vascular tone via three signaling pathways: the prostacyclin, the endothelin-1, and the nitric oxide. Although over the past 20 years, there has been considerable progress in terms of treatments for PAH, the disease still remains incurable with a disappointing prognosis.Areas covered: This review summarizes the pathophysiology of PAH, the advantages and disadvantages of the inhalation route, and assess the relative advantages various inhaled therapies for PAH. The recent studies concerning the development of controlled-release drug delivery systems loaded with available anti-PAH drugs have also been summarized.Expert opinion: The main obstacles of current pharmacotherapies of PAH are their short half-life, stability, and formulations, resulting in reducing the efficacy and increasing systemic side effects and unknown pathogenesis of PAH. The pulmonary route has been proposed for delivering anti-PAH drugs to overcome the shortcomings. However, the application of approved inhaled anti-PAH drugs is limited. Inhalational delivery of controlled-release nanoformulations can overcome these restrictions. Extensive studies are required to develop safe and effective drug delivery systems for PAH patients.

Use and costs of inhaled nitric oxide and inhaled epoprostenol in adult critically ill patients: A quality improvement project

PURPOSE

Inhaled epoprostenol and inhaled nitric oxide are pulmonary vasodilators commonly used in the management of acute respiratory distress syndrome and right ventricular failure; however, they have vastly different cost profiles. The purpose of the project was to transition from nitric oxide to epoprostenol as the inhaled pulmonary vasodilator (IPV) of choice in adult critically ill patients and evaluate the effect of the transition on associated usage and costs.

METHODS

A single-center, prospective, before and after quality improvement project including adult patients receiving inhaled nitric oxide, inhaled epoprostenol, or both was conducted in 7 adult intensive care units, operating rooms, and postanesthesia care units of a tertiary care academic medical center. The total number of patients, hours of therapy, and costs for each agent were compared between stages of protocol implementation and annually.

RESULTS

Seven hundred twenty-nine patients received inhaled nitric oxide, inhaled epoprostenol, or both during the study period. The monthly inhaled nitric oxide use in number of patients, hours, and cost decreased during all stages of the project (p < 0.01). The monthly inhaled epoprostenol use in number of patients, hours, and cost increased during all stages (p < 0.01). Overall, total IPV use increased during the study. However, despite this increase in usage, there was a 47% reduction in total IPV cost.

CONCLUSION

Implementation of a staged protocol to introduce and expand inhaled epoprostenol use in adult critically ill patients resulted in decreased use and cost of inhaled nitric oxide. The total cost of all IPV was decreased by 47% despite increased IPV use.

Postoperative Management for Patients With Durable Mechanical Circulatory Support Devices

Mechanical circulatory support devices have been approved as bridge to transplantation, as bridge to recovery, or as destination therapy to treat end-stage heart failure. The perioperative challenges for the anesthesiologist and the intensivist caring for these patients include device-related complications, hemodynamic instability, arrhythmias, right ventricular failure, and coagulopathy. Perioperative management in this high-risk population has a significant impact on patient outcomes. This review focuses immediate postoperative intensive care unit management of device-related complications.

Clinical and Economic Impact of Formulary Conversion From Inhaled Flolan to Inhaled Veletri for Refractory Hypoxemia in Critically Ill Patients

BACKGROUND

Flolan (iFLO) and Veletri (iVEL) are 2 inhaled epoprostenol formulations. There is no published literature comparing these formulations in critically ill patients with refractory hypoxemia.

OBJECTIVE

To compare efficacy, safety, and cost outcomes in patients who received either iFLO or iVEL for hypoxic respiratory failure.

METHODS

This was a retrospective, single-center analysis of adult, mechanically ventilated patients receiving iFLO or iVEL for improvement in oxygenation. The primary end point was the change in the PaO2/FiO2 ratio after 1 hour of pulmonary vasodilator therapy. Secondary end points assessed were intensive care unit (ICU) length of stay (LOS), hospital LOS, duration of study therapy, duration of mechanical ventilation, mortality, incidence of adverse events, and cost.

RESULTS

A total of 104 patients were included (iFLO = 52; iVEL = 52). More iFLO patients had acute respiratory distress syndrome compared with the iVEL group (61.5 vs 34.6%; P = 0.01). There was no difference in the change in the PaO2/FiO2 ratio after 1 hour of therapy (33.04 ± 36.9 vs 31.47 ± 19.92; P = 0.54) in the iFLO and iVEL groups, respectively. Patients who received iVEL had a shorter duration of mechanical ventilation (P < 0.001) and ICU LOS (P < 0.001) but not hospital LOS (P = 0.86) and duration of therapy (P = 0.36). No adverse events were attributed to pulmonary vasodilator therapy, and there was no difference in cost.

CONCLUSIONS

We found no difference between iFLO and iVEL when comparing the change in the PaO2/FiO2 ratio, safety, and cost in hypoxic, critically ill patients. There were differences in secondary outcomes, likely a result of differences in underlying indication for inhaled epoprostenol.

A Comparison of Inhaled Nitric Oxide Versus Inhaled Epoprostenol for Acute Pulmonary Hypertension Following Cardiac Surgery

BACKGROUND

Direct comparisons of inhaled nitric oxide (iNO) to inhaled epoprostenol (iEPO) in patients with acute pulmonary hypertension (PHT) following cardiac surgery are lacking.

OBJECTIVE

To compare the relative efficacy, safety, and cost of iNO versus iEPO in patients with acute PHT following cardiac surgery.

METHODS

This is a single-center, retrospective, observational, cohort study comparing iNO to iEPO for acute postoperative PHT following cardiac surgery. The primary outcome was reduction of mean pulmonary artery pressure (mPAP) to < 30 mm Hg, 6 hours after ICU admission from the operating room. Secondary outcomes, included ICU and hospital length of stay, duration of mechanical ventilation, bleeding complications, hypotension, in-hospital mortality, and cost.

RESULTS

A total of 98 patients met inclusion criteria (iNO, n = 49; iEPO, n = 49). There was no difference in the primary outcome of reduction of mPAP to < 30 mm Hg 6 hours after ICU admission (iNO, 33 [67%] vs iEPO, 35 [71%]; P = 0.83) or in the incidence of adverse events collected (iNO, 10 [20%] vs iEPO, 11 [22%]; P = 1.00). Based on cost estimates, the median cost of iEPO per patient was $363.53 ($226-$864.60) versus $2562.50 ($1875-$8625) for iNO (P < 0.01).

CONCLUSIONS

The relative efficacy of iEPO appeared to be similar to that of iNO in reducing mPAP following cardiac surgery, in this retrospective review. Significant cost savings were associated with the use of iEPO.

Noninferiority of Inhaled Epoprostenol to Inhaled Nitric Oxide for the Treatment of ARDS

Background: Inhaled nitric oxide and inhaled epoprostenol have been evaluated for the management of hypoxemia in acute respiratory distress syndrome, with clinical trials demonstrating comparable improvements in oxygenation. However, these trials have several limitations, making it difficult to draw definitive conclusions regarding clinical outcomes. Objective: The aim of this study was to evaluate the noninferiority and safety of inhaled epoprostenol compared with inhaled nitric oxide in mechanically ventilated acute respiratory distress syndrome (ARDS) patients with a primary outcome of ventilator-free days from day 1 to day 28. Methods: This was a retrospective, noninterventional, propensity-matched, noninferiority cohort study. Propensity score for receipt of inhaled nitric oxide was developed and patients were matched accordingly using a prespecified algorithm. Secondary objectives included evaluating day 28 intensive care unit–free days, changes in PaO2/FiO2 ratio after inhalation therapy initiation, and hospital mortality. Safety endpoints assessed included hypotension, methemoglobinemia, renal dysfunction, rebound hypoxemia, significant bleeding, and thrombocytopenia. Results: Ninety-four patients were included, with 47 patients in each group. Patients were well-matched with similar baseline characteristics, except patients in inhaled nitric oxide group had lower PaO2/FiO2 ratio. Management of ARDS was similar between groups. Mean difference in ventilator-free days between inhaled epoprostenol and inhaled nitric oxide was 2.16 days (95% confidence interval = −0.61 to 4.9), with lower limit of 95% confidence interval greater than the prespecified margin, hence satisfying noninferiority. There were no differences in any secondary or safety outcomes. Conclusions: Inhaled epoprostenol was noninferior to inhaled nitric oxide with regard to ventilator-free days from day 1 to day 28 in ARDS patients.

Evaluation of US20150011555. An inhaled IP receptor agonist for the treatment of pulmonary arterial hypertension

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a rare disease for which IP receptor agonists provide one of the main classes of treatment. Currently available agents tend to lack receptor selectivity.

AREAS COVERED

Four salts of 7-(2,3-di-p-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoic acid, crystalline forms and compositions of each of these salts, and their use to treat conditions mediated by IP receptor activation, in particular PAH, are claimed. The claimed salts are particularly suited for delivery via inhalation and inhalation devices for their administration are claimed.

EXPERT OPINION

This IP receptor agonist represents the first example of selecting a compound to treat PAH that was designed for delivery via inhalation. It indicates Novartis' desire to establish a broad portfolio of respiratory products.

Pulmonary Hypertension in the Intensive Care Unit

Pulmonary hypertension occurs as the result of disease processes increasing pressure within the pulmonary circulation, eventually leading to right ventricular failure. Patients may become critically ill from complications of pulmonary hypertension and right ventricular failure or may develop pulmonary hypertension as the result of critical illness. Diagnostic testing should evaluate for common causes such as left heart failure, hypoxemic lung disease and pulmonary embolism. Relatively few patients with pulmonary hypertension encountered in clinical practice require specific pharmacologic treatment of pulmonary hypertension targeting the pulmonary vasculature. Management of right ventricular failure involves optimization of preload, maintenance of systemic blood pressure and augmentation of inotropy to restore systemic perfusion. Selected patients may require pharmacologic therapy to reduce right ventricular afterload by directly targeting the pulmonary vasculature, but only after excluding elevated left heart filling pressures and confirming increased pulmonary vascular resistance. Critically-ill patients with pulmonary hypertension remain at high risk of adverse outcomes, requiring a diligent and thoughtful approach to diagnosis and treatment.

Proposed management algorithm for severe hypoxemia after liver transplantation in the hepatopulmonary syndrome

The hepatopulmonary syndrome (HPS) is defined as the triad of liver disease, intrapulmonary vascular dilatation, and abnormal gas exchange, and is found in 10-32% of patients with liver disease. Liver transplantation is the only known cure for HPS, but patients can develop severe posttransplant hypoxemia, defined as a need for 100% inspired oxygen to maintain a saturation of ≥85%. This complication is seen in 6-21% of patients and carries a 45% mortality. Its management requires the application of specific strategies targeting the underlying physiologic abnormalities in HPS, but awareness of these strategies and knowledge on their optimal use is limited. We reviewed existing literature to identify strategies that can be used for this complication, and developed a clinical management algorithm based on best evidence and expert opinion. Evidence was limited to case reports and case series, and we determined which treatments to include in the algorithm and their recommended sequence based on their relative likelihood of success, invasiveness, and risk. Recommended therapies include: Trendelenburg positioning, inhaled epoprostenol or nitric oxide, methylene blue, embolization of abnormal pulmonary vessels, and extracorporeal life support. Availability and use of this pragmatic algorithm may improve management of this complication, and will benefit from prospective validation.

Effects of acute intravenous iloprost on right ventricular hemodynamics in rats with chronic pulmonary hypertension

The inotropic effects of prostacyclins in chronic pulmonary arterial hypertension (PAH) are unclear and may be important in directing patient management in the acute setting. We sought to study the effects of an acute intravenous (IV) infusion of iloprost on right ventricular (RV) contractility in a rat model of chronic PAH. Rats were treated with monocrotaline, 60 mg/kg intraperitoneally, to induce PAH. Six weeks later, baseline hemodynamic assessment was performed with pressure-volume and Doppler flow measurements. In one group of animals, measurements were repeated 10-15 minutes after IV infusion of a fixed dose of iloprost (20 μg/kg). A separate group of rats underwent dose-response assessment. RV contractility and RV-pulmonary artery coupling were assessed by the end-systolic pressure-volume relationship (ESPVR) and end-systolic elastance/effective arterial elastance (Ees/Ea). RV cardiomyocytes were isolated, and intracellular cAMP (cyclic adenosine monophosphate) concentration was measured with a cAMP-specific enzyme immunoassay kit. Animals had evidence of PAH and RV hypertrophy. Right ventricle/(left ventricle + septum) weight was 0.40 ± 0.03. RV systolic pressure (RVSP) was 39.83 ± 1.62 mmHg. Administration of iloprost demonstrated an increase in the slope of the ESPVR from 0.29 ± 0.02 to 0.42 ± 0.05 (P < .05). Ees/Ea increased from 0.63 ± 0.07 to 0.82 ± 0.06 (P < .05). The RV contractility index (max dP/dt normalized for instantaneous pressure) increased from 94.11 to 114.5/s (P < .05), as did the RV ejection fraction, from 48.0% to 52.5% (P < .05). This study suggests a positive inotropic effect of iloprost on a rat model of chronic PAH.

A review of inhaled nitric oxide and aerosolized epoprostenol in acute lung injury or acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are conditions associated with an estimated mortality of 40–50%. The use of inhaled vasodilators can help to improve oxygenation without hemodynamic effects. This article reviews relevant studies addressing the safety and efficacy of inhaled nitric oxide (iNO) and aerosolized epoprostenol (aEPO) in the treatment of life-threatening hypoxemia associated with ARDS and ALI. In addition, the article also provides a practicable guide to the clinical application of these therapies. Nine prospective randomized controlled trials were included for iNO reporting on changes in oxygenation or clinical outcomes. Seven reports of aEPO were examined for changes in oxygenation. Based on currently available data, the use of either iNO or aEPO is safe to use in patients with ALI or ARDS to transiently improve oxygenation. No differences have been observed in survival, ventilator-free days, or attenuation in disease severity. Further studies with consistent end points using standard delivery devices and standard modes of mechanical ventilation are needed to determine the overall benefit with iNO or aEPO.

Management of pulmonary vasodilator therapy in patients with pulmonary arterial hypertension during critical illness

Pulmonary arterial hypertension (PAH) is commonly treated with pulmonary arteriolar vasodilator therapy. When a patient on PAH medication is admitted to intensive care, determining how to manage their medication during the critical illness is often complicated. There may be considerations related to the inability to take medication by mouth, related to acute renal failure or acute liver injury, related to altered mental status or delirium, or related to hypotension and bacteremia. Decisions of how to manage these medications can have a major impact on the patient’s clinical course. Presently, provider experience is the major tool in navigating the decisions regarding these medications. In this review, we offer our recommendations of how to manage PAH patients with critical illness who are on PAH medications. These recommendations include how to deliver medications via feeding tubes, how to dose medications in the setting of acute renal failure or acute liver failure, and how to manage medications during hypotension or when a tunneled catheter needs to be removed.

Inhaled epoprostenol vs inhaled nitric oxide for refractory hypoxemia in critically ill patients

PURPOSE

The purpose of this is to compare efficacy, safety, and cost outcomes in patients who have received either inhaled epoprostenol (iEPO) or inhaled nitric oxide (iNO) for hypoxic respiratory failure.

MATERIALS AND METHODS

This is a retrospective, single-center analysis of adult, mechanically ventilated patients receiving iNO or iEPO for improvement in oxygenation.

RESULTS

We evaluated 105 mechanically ventilated patients who received iEPO (52 patients) or iNO (53 patients) between January 2009 and October 2010. Most patients received therapy for acute respiratory distress syndrome (iNO 58.5% vs iEPO 61.5%; P=.84). There was no difference in the change in the partial pressure of arterial O2/fraction of inspired O2 ratio after 1 hour of therapy (20.58±91.54 vs 33.04±36.19 [P=.36]) in the iNO and iEPO groups, respectively. No difference was observed in duration of therapy (P=.63), mechanical ventilation (P=.07), intensive care unit (P=.67), and hospital lengths of stay (P=.26) comparing the iNO and iEPO groups. No adverse events were attributed to either therapy. Inhaled nitric oxide was 4.5 to 17 times more expensive than iEPO depending on contract pricing.

CONCLUSIONS

We found no difference in efficacy and safety outcomes when comparing iNO and iEPO in hypoxic, critically ill patients. Inhaled epoprostenol is associated with less drug expenditure than iNO.

In vitro delivery of aerosolized treprostinil via modern mechanical ventilation

BACKGROUND

The Tyvaso Inhalation System is a hand-held nebulizer system used to administer treprostinil, an approved therapy for pulmonary arterial hypertension. Our goal was to establish an in vitro method for delivering a standard dose of treprostinil through a ventilator circuit and artificial airway.

METHODS

An AeroTech II jet nebulizer (continuous air flow at 10 L/min; Biodex Medical Systems) was placed in the ventilator circuit with a test lung. Two ventilators were tested, the Dräger Evita 2 Dura (Dräger Medical GmbH) and Avea (CareFusion), without humidity. Delivered dose was defined by capturing radiolabeled particles exiting the endotracheal tube with a filter (Pari) and measuring radioactivity. Particle distributions were measured distal to the endotracheal tube by cascade impaction. We hypothesized that drug delivery would be determined by the number of breaths needed, such that the complete time of inspiration totaled 29 sec (e.g., number of breaths needed=29 sec/TI, where TI is the inspiratory time of an average breath read from the ventilator display).

RESULTS

Nebulizer output was linear for 6 min, and the standard prescribed target dose of 54 μg (3.1% of full ampule) was delivered in 29 sec. Using our TI algorithm to control delivery, the mean inhaled dose±SD was 72.2±16.5 μg (range 47.2-98.6; n=23). Dräger delivered higher doses than Avea. Effects of mode, breathing pattern, and positive-end expiratory pressures were not significant. The mass median aerodynamic diameter and fine particle fraction were 0.71±0.015 and 0.997±0.0006, respectively.

CONCLUSIONS

Using the algorithm, it was possible to deliver aerosolized treprostinil, at controlled doses, via mechanical ventilation over a wide range of controlled breathing patterns. The conditions of nebulization must be precisely followed (one full ampule per treatment, use of the AeroTech II nebulizer, continuous nebulization using an external flow of 10 L/min, bypass of the humidifier or removal of in-line heat and moisture exchanger, and treatment completed in 6 min or less).

Efficacy, Safety, and Medication Errors Associated with the Use of Inhaled Epoprostenol for Adults with Acute Respiratory Distress Syndrome: A Pilot Study

BACKGROUND:

Acute respiratory distress syndrome (ARDS) is a type of hypoxic respiratory failure that results from ventilation and perfusion mismatching. Inhaled epoprostenol induces relaxation of smooth muscle in pulmonary vasculature, leading to improved oxygenation.

OBJECTIVE:

To determine if the use of inhaled epoprostenol produced a 10% or greater increase in the ratio of arterial partial pressure of oxygen (PaO2) to fraction of inspired oxygen (FiO2) in ARDS patients and to review adverse events and medication errors.

METHODS:

An observational chart review was performed based on a report generated from the electronic medical record system. Patients who received at least 1 dose of inhaled epoprostenol from January 1, 2008, to December 31, 2010, at any hospital within the Florida Hospital Health System were considered for inclusion. Demographics, dose, duration of therapy, adverse effects, medication errors, and outcomes data were collected.

RESULTS:

Sixteen patients were included in the study. Oxygenation improved by 10% or more in 62.5% (10/16) of the patients, with an initial (within the first 4 hours) median increase of 44.5% in PaO2/FiO2. The mean (SD) starting dose was 30 (10) ng/kg/min. Medication errors were observed in 25% (4/16) of patients. Hypotension was the most frequently observed adverse event, with a rate of 18.8% (3/16).

CONCLUSIONS:

Based on study findings, inhaled epoprostenol may improve oxygenation in patients with ARDS, with findings suggesting a 62.5% response to therapy. The significance of these effects on improving survival remains unknown. The frequency of medication errors observed in this study poses a significant concern regarding the administration of epoprostenol. Further controlled prospective studies are needed to determine the role of inhaled epoprostenol in improving survival in patients with ARDS.

Inhaled iloprost for patients with precapillary pulmonary hypertension and right-side heart failure

Background

Pulmonary hypertension (PH) can lead to right-side heart failure (RHF) and death. There are no therapeutic recommendations for patients experiencing acute RHF in the course of PH. This study aimed to examine the safety and efficacy of inhaled iloprost in patients with precapillary PH and RHF.

Methods and Results

Between October 2007 and December 2008, 7 patients with precapillary PH and RHF were enrolled. Per protocol, iloprost was inhaled hourly for a minimum of 12 hours during a 24-hour period. The starting dose of 2.5 μg was increased hourly by 2.5 μg as long as the increases were tolerated. Safety and efficacy were determined by continuous invasive monitoring of systemic and pulmonary hemodynamic parameters. Systemic pressures remained stable during inhalation (66.1 ± 6.9 mm Hg at baseline and 69.1 ± 6.4 mm Hg immediately after inhalation therapy, P = 0.48). Cardiac index increased from 2.4 ± 0.7 L/min/m² to 2.9 ± 0.9 L/min/m² (P = .008). Pulmonary vascular resistance decreased from 634.6 ± 218.3 dyn·s·cm⁻⁵ to 489.6 ± 173.8 dyn·s·cm⁻⁵ (P = .044), and N-terminal B-type natriuretic peptide levels decreased from 13,591 ± 10,939 pg/mL to 9,944 ± 8,569 pg/mL (P = .051).

Conclusion

Blood pressure-guided hourly inhalation of iloprost may offer a safe and effective strategy for the treatment of PH patients with RHF.

Prostacyclins in pulmonary arterial hypertension: the need for earlier therapy

Pulmonary arterial hypertension (PAH) is a rare but serious condition, which if untreated, is associated with a 2-3-year median survival time. A number of treatment options are available for PAH, leading to improvements in exercise capacity, symptoms, and hemodynamics. However, the disease remains incurable and most patients will ultimately progress to right heart failure and death. Three classes of drugs are currently available to improve PAH outcomes, although this review will focus solely on a class of potent vasodilators known as prostacyclins. Currently, four prostacyclin analogs are licensed for the treatment of PAH: epoprostenol, treprostinil, and iloprost in the USA and some European countries, and beraprost in Japan and Korea. Prostacyclins have become the treatment of choice in patients with severe PAH, but there is also evidence to suggest that their earlier use may also benefit patients with mild-to-moderate disease. This review discusses the advantages of prostacyclins in terms of their usefulness in patients whose condition has deteriorated following monotherapy with other agents, and their integral role in combination therapy. The latter appears to offer the potential for pulmonary vasculature remodeling and could be regarded as an emerging paradigm to treat and prevent the progression of PAH.