Inhaled prostacyclin is safe, effective, and affordable in patients with pulmonary hypertension, right heart dysfunction, and refractory hypoxemia after cardiothoracic surgery

Right Heart Failure in the Intensive Care Unit: Etiology, Pathogenesis, Diagnosis, and Treatment

Right heart (RH) failure carries a high rate of morbidity and mortality. Patients who present with RH failure often exhibit complex aberrant cardio-pulmonary physiology with varying presentations. The treatment of RH failure almost always requires care and management from an intensivist. Treatment options for RH failure patients continue to evolve rapidly with multiple options available, including different pharmacotherapies and mechanical circulatory support devices that target various components of the RH circulatory system. An understanding of the normal RH circulatory physiology, treatment, and support options for the RH failure patients is necessary for all intensivists to improve outcomes. The purpose of this review is to provide clinical guidance on the diagnosis and management of RH failure within the intensive care unit setting, and to highlight the different pathophysiological manifestations of RH failure, its hemodynamics, and treatment options available at the disposal of the intensivist.

Inhaled Epoprostenol Compared With Nitric Oxide for Right Ventricular Support After Major Cardiac Surgery

BACKGROUND

Right ventricular failure (RVF) is a leading driver of morbidity and death after major cardiac surgery for advanced heart failure, including orthotopic heart transplantation and left ventricular assist device implantation. Inhaled pulmonary-selective vasodilators, such as inhaled epoprostenol (iEPO) and nitric oxide (iNO), are essential therapeutics for the prevention and medical management of postoperative RVF. However, there is limited evidence from clinical trials to guide agent selection despite the significant cost considerations of iNO therapy.

METHODS

In this double-blind trial, participants were stratified by assigned surgery and key preoperative prognostic features, then randomized to continuously receive either iEPO or iNO beginning at the time of separation from cardiopulmonary bypass with the continuation of treatment into the intensive care unit stay. The primary outcome was the composite RVF rate after both operations, defined after transplantation by the initiation of mechanical circulatory support for isolated RVF, and defined after left ventricular assist device implantation by moderate or severe right heart failure according to criteria from the Interagency Registry for Mechanically Assisted Circulatory Support. An equivalence margin of 15 percentage points was prespecified for between-group RVF risk difference. Secondary postoperative outcomes were assessed for treatment differences and included: mechanical ventilation duration; hospital and intensive care unit length of stay during the index hospitalization; acute kidney injury development including renal replacement therapy initiation; and death at 30 days, 90 days, and 1 year after surgery.

RESULTS

Of 231 randomized participants who met eligibility at the time of surgery, 120 received iEPO, and 111 received iNO. Primary outcome occurred in 30 participants (25.0%) in the iEPO group and 25 participants (22.5%) in the iNO group, for a risk difference of 2.5 percentage points (two one-sided test 90% CI, -6.6% to 11.6%) in support of equivalence. There were no significant between-group differences for any of the measured postoperative secondary outcomes.

CONCLUSIONS

Among patients undergoing major cardiac surgery for advanced heart failure, inhaled pulmonary-selective vasodilator treatment using iEPO was associated with similar risks for RVF development and development of other postoperative secondary outcomes compared with treatment using iNO.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03081052.

The perioperative use of inhaled prostacyclins in cardiac surgery: a systematic review and meta-analysis

PURPOSE

Perioperative pulmonary hypertension (PH) is an independent risk factor for morbidity and mortality in cardiac surgery. While inhaled prostacyclins (iPGI2s) are an established treatment of chronic PH, data on the efficacy of iPGI2s in perioperative PH are scarce.

METHODS

We searched PubMed, Embase, the Web of Science, CENTRAL, and the grey literature from inception until April 2021. We included randomized controlled trials investigating the use of iPGI2s in adult and pediatric patients undergoing cardiac surgery with an increased risk of perioperative right ventricle failure. We assessed the efficacy and safety of iPGI2s compared with placebo and other inhaled or intravenous vasodilators with random-effect meta-analyses. The primary outcome was mean pulmonary artery pressure (MPAP). Secondary outcomes included other hemodynamic parameters and mortality.

RESULTS

Thirteen studies were included, comprising 734 patients. Inhaled prostacyclins significantly decreased MPAP compared with placebo (standardized effect size, 0.46; 95% confidence interval [CI], 0.11 to 0.87; P = 0.01) and to intravenous vasodilators (1.26; 95% CI, 0.03 to 2.49; P = 0.045). Inhaled prostacyclins significantly improved the cardiac index compared with intravenous vasodilators (1.53; 95% CI, 0.50 to 2.57; P = 0.004). In contrast, mean arterial pressure was significantly lower in patients treated with iPGI2s vs placebo (-0.39; 95% CI, -0.62 to 0.16; P = 0.001), but higher than in patients treated with intravenous vasodilators (0.81; 95% CI, 0.29 to 1.33; P = 0.002). With respect to hemodynamics, iPGI2s had similar effects as other inhaled vasodilators. Mortality was not affected by iPGI2s.

CONCLUSION

The results of this systematic review and meta-analysis show that iPGI2s improved pulmonary hemodynamics with similar efficacy as other inhaled vasodilators, but caused a significant small decrease in arterial pressure when compared with placebo, indicating spill-over into the systemic circulation. These effects did not affect clinical outcomes.

STUDY REGISTRATION DATE

PROSPERO (CRD42021237991); registered 26 May 2021.

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.

Acute Respiratory Distress Syndrome and the Use of Inhaled Pulmonary Vasodilators in the COVID-19 Era: A Narrative Review

The Coronavirus disease (COVID-19) pandemic of 2019 has resulted in significant morbidity and mortality, especially from severe acute respiratory distress syndrome (ARDS). As of September 2022, more than 6.5 million patients have died globally, and up to 5% required intensive care unit treatment. COVID-19-associated ARDS (CARDS) differs from the typical ARDS due to distinct pathology involving the pulmonary vasculature endothelium, resulting in diffuse thrombi in the pulmonary circulation and impaired gas exchange. The National Institute of Health and the Society of Critical Care Medicine recommend lung-protective ventilation, prone ventilation, and neuromuscular blockade as needed. Further, a trial of pulmonary vasodilators is suggested for those who develop refractory hypoxemia. A review of the prior literature on inhaled pulmonary vasodilators in ARDS suggests only a transient improvement in oxygenation, with no mortality benefit. This narrative review aims to highlight the fundamental principles in ARDS management, delineate the fundamental differences between CARDS and ARDS, and describe the comprehensive use of inhaled pulmonary vasodilators. In addition, with the differing pathophysiology of CARDS from the typical ARDS, we sought to evaluate the current evidence regarding the use of inhaled pulmonary vasodilators in CARDS.

The Diagnosis and Treatment of Postoperative Right Heart Failure

BACKGROUND

Acute right heart failure is a life-threatening condition that can arise postoperatively. The options for symptomatic treatment have been markedly expanded in recent years through the introduction of percutaneously implantable mechanical cardiac support systems.

METHODS

This review is based on publications retrieved by a selective literature search in PubMed as well as on guidelines from Germany and abroad.

RESULTS

The diagnostic evaluation of right heart failure is chiefly based on echocardiography and pulmonary arterial catheteri - zation and is intended to lead to immediate treatment. Alongside treatment of the cause of the condition, supportive management is crucial to patient survival. A variety of ventilation strategies depending on the situation, catecholamine therapies, inhaled selective pulmonary vasodilators, and cardiac support systems are available for this purpose. The in-hospital mortality of postoperative right heart failure is 5-17 %. The results of the use of cardiac support systems reported in case series are dis - appointing, but nonetheless good compared to what these critically ill patients would face without such treatment. In one observational study, the 30-day survival rate was 73.3%.

CONCLUSION

Survival is aided by the rapid recognition of right heart failure, targeted multidisciplinary treatment, and contact with an extracorporeal life support (ECLS) center for additional supportive treatment measures. Further studies on the use of pharmacological and mechanical cardiac support systems must be carried out to provide stronger evidence on which treatment recommendations can be based.

A retrospective review of implementation of an inhaled epoprostenol protocol in the emergency department

INTRODUCTION

Inhaled epoprostenol is a selective pulmonary vasodilator that has shown a potentially broad number of applications in the management of critically ill patients. To date, the vast majority of the literature with regard to efficacy, indications for use, and adverse effects of inhaled epoprostenol is focused on use of this agent in critical care settings, with relatively little literature describing use of inhaled epoprostenol in the Emergency Department. This retrospective review sought to examine instances in which inhaled epoprostenol was administered in the Emergency Department of a tertiary-care, Level I trauma center following implementation of a clinical pathway for administration of this medication for cases of refractory hypoxemia, RV dysfunction, and refractory hypoxemia. Primary outcomes were monitoring for adverse effects (i.e. hypotension), trend in FiO2 requirement over time, and clinical indication for initiation of inhaled epoprostenol.

METHODS

An automated review was performed to query cases in which inhaled epoprostenol had been initiated in the Emergency Department following adoption of the inhaled epoprostenol clinical pathway. Cases were excluded if the medication was initiated in the prehospital setting, ordered but not administered, or administered for a period of <1 h. Vital signs and co-administration of vasopressors were followed before and following epoprostenol administration to assess for change over time. Clinical indication of epoprostenol administration was assessed via manual chart review.

RESULTS

Inhaled epoprostenol was administered in 20 instances, with 15 cases ultimately meeting inclusion criteria. There were no cases of clinically significant hypotension (MAP <65) in any of the cases in which inhaled epoprostenol was administered in the Emergency Department, and mean vasopressor requirement did not increase over time. A majority of patients saw a reduction in FiO2 requirement following administration of inhaled epoprostenol. The most common indication for initiation of inhaled epoprostenol based on manual chart review was pulmonary embolism.

DISCUSSION

In this review of cases in which inhaled epoprostenol was administered following adoption of a clinical pathway for medication administration, there were no cases of hypotension or other adverse effects that appear to be attributable to medication administration. Pulmonary embolism and refractory hypoxemia were the most common noted indications for administration of inhaled epoprostenol. Further research is warranted regarding development of clinical protocols for administration of inhaled pulmonary vasodilators in the Emergency Department setting.

Compassionate use of Pulmonary Vasodilators in Acute Severe Hypoxic Respiratory Failure due to COVID-19

Background

There have been over 200 million cases and 4.4 million deaths from COVID-19 worldwide. Despite the lack of robust evidence one potential treatment for COVID-19 associated severe hypoxaemia is inhaled pulmonary vasodilator (IPVD) therapy, using either nitric oxide (iNO) or prostaglandins. We describe the implementation of, and outcomes from, a protocol using IPVDs in a cohort of patients with severe COVID-19 associated respiratory failure receiving maximal conventional support.

Methods

Prospectively collected data from adult patients with SARS-CoV-2 admitted to the intensive care unit (ICU) at a large teaching hospital were analysed for the period 14^th March 2020 - 11^th February 2021. An IPVD was considered if the PaO₂/FiO₂ (PF) ratio was less than 13.3kPa despite maximal conventional therapy. Nitric oxide was commenced at 20ppm and titrated to response. If oxygenation improved Iloprost nebulisers were commenced and iNO weaned. The primary outcome was percentage changes in PF ratio and Alveolar-arterial (A-a) gradient.

Results

Fifty-nine patients received IPVD therapy during the study period. The median PF ratio before IPVD therapy was commenced was 11.33kPa (9.93-12.91). Patients receiving an IPVD had a lower PF ratio (14.37 vs. 16.37kPa, p = 0.002) and higher APACHE-II score (17 vs. 13, p = 0.028) at ICU admission. At 72 hours after initiating an IPVD the median improvement in PF ratio was 33.9% (-4.3-84.1). At 72 hours changes in PF ratio (70.8 vs. −4.1%, p < 0.001) and reduction in A-a gradient (44.7 vs. 14.8%, p < 0.001) differed significantly between survivors (n = 33) and non-survivors (n = 26).

Conclusions

The response to IPVDs in patients with COVID-19 associated acute hypoxic respiratory failure differed significantly between survivors and non-survivors. Both iNO and prostaglandins may offer therapeutic options for patients with severe refractory hypoxaemia due to COVID-19. The use of inhaled prostaglandins, and iNO where feasible, should be studied in adequately powered prospective randomised trials.

The Use of Inhaled Epoprostenol for Acute Respiratory Distress Syndrome Secondary due to COVID-19: A Case Series

Introduction

Inhaled epoprostenol (iEpo) is a pulmonary vasodilator used to treat refractory respiratory failure, including that caused by Coronavirus 2019 (COVID-19) pneumonia.

Aim of Study

To describe the experience at three teaching hospitals using iEpo for severe respiratory failure due to COVID-19 and evaluate its efficacy in improving oxygenation.

Methods

Fifteen patients were included who received iEpo, had confirmed COVID-19 and had an arterial blood gas measurement in the 12 hours before and 24 hours after iEpo initiation.

Results

Eleven patients received prone ventilation before iEpo (73.3%), and six (40%) were paralyzed. The partial pressure of arterial oxygen to fraction of inspired oxygen (P/F ratio) improved from 95.7 mmHg to 118.9 mmHg (p=0.279) following iEpo initiation. In the nine patients with severe ARDS, the mean P/F ratio improved from 66.1 mmHg to 95.7 mmHg (p=0.317). Ultimately, four patients (26.7%) were extubated after an average of 9.9 days post-initiation.

Conclusions

The findings demonstrated a trend towards improvement in oxygenation in critically ill COVID-19 patients. Although limited by the small sample size, the results of this case series portend further investigation into the role of iEpo for severe respiratory failure associated with COVID-19.

Unexpected Interruptions in the Inhaled Epoprostenol Delivery System: Incidence of Adverse Sequelae and Therapeutic Consequences in Critically Ill Patients

OBJECTIVES

Inhaled epoprostenol is a continuously delivered selective pulmonary vasodilator that is used in patients with refractory hypoxemia, right heart failure, and postcardiac surgery pulmonary hypertension. Published data suggest that inhaled epoprostenol administration via vibrating mesh nebulizer systems may lead to unexpected interruptions in drug delivery. The frequency of these events is unknown. The objective of this study was to describe the incidence and clinical consequences of unexpected interruption in critically ill patients.

DESIGN

Retrospective review and analysis.

SETTING

Stanford University Hospital, a 605-bed tertiary care center.

PATIENTS

Patients receiving inhaled epoprostenol in 2019.

INTERVENTIONS

No interventions.

MEASUREMENTS AND MAIN RESULTS

Clinical indication, duration of inhaled epoprostenol delivery, mode of respiratory support, and documented unexpected interruption. In 2019, there were 493 administrations of inhaled epoprostenol in 433 unique patients. Primary indications for inhaled epoprostenol were right heart dysfunction (n = 394; 79.9%) and hypoxemia (n = 92; 18.7%). Unexpected delivery interruptions occurred in 31 administrations (6.3%). Median duration of therapy prior to unexpected interruption was 2 days (interquartile range, 2-5 d). Respiratory support at the time of unexpected interruption was mechanical ventilation (61.3%), high-flow nasal cannula (35.5%), and noninvasive positive pressure ventilation (3.2%). Adverse sequelae of unexpected interruption included elevated pulmonary artery pressures (n = 12), systemic hypotension (n = 8), hypoxemia (n = 8), elevated central venous pressure (n = 4), and cardiac arrest (n = 1). Therapeutic interventions following unexpected interruption included initiation of inhaled nitric oxide (n = 21), increase in vasoactive medication (n = 2), and increase in respiratory support (n = 2). Most of the adverse events were Common Terminology Criteria for Adverse Events grade 3 and 4 (93.5%).

CONCLUSIONS

A retrospective review of patients receiving inhaled epoprostenol via vibrating mesh nebulizer in 2019 revealed interruptions in 6.3% of administrations with most of these interruptions requiring therapeutic intervention. The true incidence of unexpected interruption and subsequent rate of unexpected interruption's requiring intervention is unknown due to the reliance on unexpected interruption identification and subsequent documentation in the electronic medical record. Sudden interruption in inhaled epoprostenol delivery can result in severe cardiopulmonary compromise, and on rare occasion, death.

Inhaled prostacyclin analogues in COVID-19 associated acute respiratory distress syndrome: scientific rationale

BACKGROUND

COVID-19 associated acute respiratory distress syndrome (CARDS) is a severe form of SARS CoV-2 infection and affects about 15-30% of hospitalized patients with a high mortality rate. Growing research and data suggest several available drugs with appropriate pharmacological effects to treat COVID-19.

MAIN BODY

Prostacyclin analogues are regiments for pulmonary artery hypertension. Prostacyclin analogues are expected to be beneficial in treating CARDS based on at least four rationales: (1) inhaled prostacyclin analogues improve oxygenation, V/Q mismatch, and act as an ARDS therapy alternative; (2) it alleviates direct SARS-CoV-2-related coagulopathy; (3) increases nitric oxide production; and (4) possible anti-inflammatory effect. Prostacyclin analogues are available in oral, intravenous, and inhaled forms. The inhaled form has the advantage over other forms, such as parenteral administration risks. Previously, a meta-analysis demonstrated the beneficial effects of inhaled prostaglandins for ARDS treatment, such as improved PaO2/FiO2 and PaO2 along with reduced pulmonary artery pressure. Currently, two ongoing randomized controlled trials are evaluating inhaled epoprostenol (VPCOVID [NCT04452669]) and iloprost (ILOCOVID [NCT04445246]) for severe COVID-19 patients.

CONCLUSIONS

Inhaled prostacyclin could be considered in patients with refractory, life-threatening hypoxia despite standard management.

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.

Compatibility and Safety Implications Associated with Interfacing Medical Devices in Neonatal Respiratory Care: A Case Example Using the Inhaled Nitric Oxide Delivery System

Over the past decade, international organizations have instituted strict regulations for the safe use of connected medical devices. The International Organization for Standardization and the Medical Device Single Audit Program instituted certifications to ensure that connected devices are compatible and operate within their proper clinical parameters. These efforts came about, in part, as a consequence of clinicians’ decisions to use nonstandard, modified, or improvised devices for purposes outside the original manufacturers’ approved parameters. Unapproved device modifications can be associated with increased risk of dosing errors, monitoring errors, tubing misconnections and serious or potentially fatal adverse events; furthermore, health care providers who implement unapproved device modifications may assume legal and financial liability should harm come to patients as a consequence of the modification. Using the inhaled nitric oxide delivery system as an example, the objective of this paper is to raise awareness of the potential dangers associated with unapproved modification and interfacing of therapeutic gas delivery systems and ventilators in the neonatal intensive care unit setting. The paper also highlights the rationale and necessity for rigorous validation processes that ensure that interfaced medical devices perform as intended in the clinical setting.

Droplet Size and Distribution of Nebulized 3% Sodium Chloride, Albuterol, and Epoprostenol by Phase Doppler Particle Analyzer

Background

Aerosolized drug therapy administered to mechanically ventilated patients is a standard part of pulmonary critical care medicine. Aerosol particle size and distribution are important factors in the optimal delivery of aerosolized drugs to ventilated patients.

Objective

The objective of this study was to characterize aerosol droplet size and distribution with laser diffraction for nebulized 3% sodium chloride, albuterol, and epoprostenol sodium (containing glycine) delivered via Aeroneb Solo Mesh Nebulizers (Aerogen, Mountain View, California).

Methods

A series of functional flow tests were run on each of 8 Solo mesh nebulizers before the study to verify accuracy of flow rates in milliliters per minute. Aerosolized droplets exiting the nebulizer heads were then measured using a phase Doppler particle analyzer. Data collected during delivery of 3% sodium chloride, albuterol, and epoprostenol sodium included aerosol droplet size distribution, mass median aerodynamic diameter (MMAD), and geometric standard deviation. For each Solo nebulizer, droplet size measurements were taken 2 cm away from the nebulizer head and 2 cm away from the wye of a heated, humidified adult ventilator circuit. For measurements taken at the wye, 4 distinct, continuous flow rates (2, 10, 20, and 40 L/min) were generated by an air pump to simulate inspiratory flows delivered with mechanical ventilation. The expiratory limb was capped, and the nebulizer head was inserted into the breathing circuit upstream of the humidifier.

Results

Each Solo nebulizer met Aerogen's recommended minimum flow rate of 0.2 mL/min, ranging from 0.23 to 0.31 mL/min. The MMAD of the 3 tested aerosols was several times smaller when measured at the wye outlet of the heated/humidified breathing circuit (0.82–2.73 µm) compared with droplets measured directly at the nebulizer outlet (MMAD, 4.6–7.3 µm). There was also significant variability across Solo heads with some ventilator flow rates. The mean MMAD at the wye for the 3% sodium chloride solution, albuterol, and epoprostenol test solutions was 1.62 µm, 1.09 µm, and 1.18 µm, respectively. The mean MMAD at the nebulizer for the 3% sodium chloride solution, albuterol, and epoprostenol test solutions was 5.37 µm, 5.73 µm, and 6.73 µm, respectively.

Conclusions

Results from this study suggest that particle size of aerosolized drugs administered via a commonly used setup for delivery of in-line aerosols to mechanically ventilated patients may be several times smaller than expected and may result in less drug being delivered to the patient than previously realized.

(Curr Ther Res Clin Exp. 2021; 82:XXX–XXX)

© 2021 Elsevier HS Journals, Inc.

Evaluation of the Efficacy and Safety of Inhaled Epoprostenol and Inhaled Nitric Oxide for Refractory Hypoxemia in Patients With Coronavirus Disease 2019

OBJECTIVES

The objectives of this study were to evaluate the efficacy and safety of inhaled epoprostenol and inhaled nitric oxide in patients with refractory hypoxemia secondary to coronavirus disease 2019.

DESIGN

Retrospective single-center study.

SETTING

ICUs at a large academic medical center in the United States.

PATIENTS

Thirty-eight adult critically ill patients with coronavirus disease 2019 and refractory hypoxemia treated with either inhaled epoprostenol or inhaled nitric oxide for at least 1 hour between March 1, 2020, and June 30, 2020.

INTERVENTIONS

Electronic chart review.

MEASUREMENTS AND MAIN RESULTS

Of 93 patients screened, 38 were included in the analysis, with mild (4, 10.5%), moderate (24, 63.2%), or severe (10, 26.3%), with acute respiratory distress syndrome. All patients were initiated on inhaled epoprostenol as the initial pulmonary vasodilator and the median time from intubation to initiation was 137 hours (68-228 h). The median change in Pao₂/Fio₂ was 0 (-12.8 to 31.6) immediately following administration of inhaled epoprostenol. Sixteen patients were classified as responders (increase Pao₂/Fio₂ > 10%) to inhaled epoprostenol, with a median increase in Pao₂/Fio₂ of 34.1 (24.3-53.9). The mean change in Pao₂ and Spo₂ was -0.55 ± 41.8 and -0.6 ± 4.7, respectively. Eleven patients transitioned to inhaled nitric oxide with a median change of 11 (3.6-24.8) in Pao₂/Fio₂. A logistic regression analysis did not identify any differences in outcomes or characteristics between the responders and the nonresponders. Minimal adverse events were seen in patients who received either inhaled epoprostenol or inhaled nitric oxide.

CONCLUSIONS

We found that the initiation of inhaled epoprostenol and inhaled nitric oxide in patients with refractory hypoxemia secondary to coronavirus disease 2019, on average, did not produce significant increases in oxygenation metrics. However, a group of patients had significant improvement with inhaled epoprostenol and inhaled nitric oxide. Administration of inhaled epoprostenol or inhaled nitric oxide may be considered in patients with severe respiratory failure secondary to coronavirus disease 2019.

Novel Toxicology Program to Support the Development of Inhaled VentaProst

Currently, off-label continuous administration of inhaled epoprostenol is used to manage hemodynamics during mitral valve surgery. A toxicology program was developed to support the use of inhaled epoprostenol during mechanical ventilation as well as pre- and postsurgery via nasal prongs. To support use in patients using nasal prongs, a Good Laboratory Practice (GLP), 14-day rat, nose-only inhalation study was performed. No adverse findings were observed at ∼50× the dose rate received by patient during off-label use. To simulate up to 48 hours continuous aerosol exposure during mechanical ventilation, a GLP toxicology study was performed using anesthetized, intubated, mechanically ventilated dogs. Dogs inhaled epoprostenol at approximately 6× and 13× the dose rate reported in off-label human studies. This novel animal model required establishment of a dog intensive care unit providing sedation, multisystem support, partial parenteral nutrition, and management of the intubated mechanically ventilated dogs for the 48-hour duration of study. Aerosol was generated by a vibrating mesh nebulizer with novel methods required to determine dose and particle size in-vitro. Continuous pH 10.5 epoprostenol was anticipated to be associated with lung injury; however, no adverse findings were observed. As no toxicity at pH 10.5 was observed with a formulation that required refrigeration, a room temperature stable formulation at pH 12 was evaluated in the same ventilated dog model. Again, there were no adverse findings. In conclusion, current toxicology findings support the evaluation of inhaled epoprostenol at pH 12 in surgical patients with pulmonary hypertension for up to 48 hours continuous exposure.

Comparison of inhaled nitric oxide with aerosolized prostacyclin or analogues for the postoperative management of pulmonary hypertension: a systematic review and meta-analysis

Background: This study aims to compare the effectiveness of inhaled prostacyclin or its analoguesversus nitric oxide (NO) in treating pulmonary hypertension (PH) after cardiac or pulmonary surgery remains unclear.Methods: PubMed, Cochrane, and Embase databases were searched for literature published prior to December 2019 using the following keywords: inhaled, nitric oxide, prostacyclin, iloprost, treprostinil, epoprostenol, Tyvaso, flolan, and pulmonary hypertension. Randomized controlled trials and multiple-armed prospective studies that evaluated inhaled NO versus prostacyclin (or analogues) in patients for perioperative and/or postoperative PH after either cardiac or pulmonary surgery were included. Retrospective studies, reviews, letters, comments, editorials, and case reports were excluded.Results: Seven studies with a total of 195 patients were included. No difference in the improvement of mean pulmonary arterial pressure (pooled difference in mean change= -0.10, 95% CI: -3.98 to 3.78, p = .959) or pulmonary vascular resistance (pooled standardized difference in mean change= -0.27, 95% CI: -0.60 to 0.05, p = .099) were found between the two treatments. Similarly, no difference was found in other outcomes between the two treatments or subgroup analysis.Conclusions: Inhaled prostacyclin (or analogues) was comparable to inhaled NO in treating PH after cardiac or pulmonary surgery.Key messagesThis study compared the efficacy of inhaled prostacyclin or its analogues versus inhaled NO to treat PH after surgery. The two types of agent exhibited similar efficacy in managing MPAP, PVR, heart rate, and cardiac output was observed.Inhaled prostacyclin may serve as an alternative treatment option for PH after cardiac or pulmonary surgery.

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.

Pulmonary Hypertension in an Oncologic Intensive Care Unit

Pulmonary hypertension (PH) is the condition of elevated pressures in the pulmonary circulation. PH can develop acutely in patients with critical illness such as acute respiratory distress syndrome, sepsis, massive pulmonary embolism, left ventricular dysfunction, or after surgery. In a cancer patient, unique etiologies such as myeloproliferative disorders, tyrosine kinase inhibitors, or tumor emboli may result in PH. Early recognition and treatment of the causative condition may reverse acute PH or return chronic PH to its baseline status. Progression of the disease or its decompensation due to infection, a thromboembolic event, or other triggers can lead to admission to an intensive care unit. Regardless of etiology, the development or worsening of PH may precipitate hypoxemia, hemodynamic instability, or right ventricular failure, which can be challenging to manage or even fatal. In select cases, rapid institution of advanced treatment modalities may be warranted. This chapter reviews the etiology, epidemiology, pathophysiology, clinical features, diagnosis, and prognosis of PH and presents a comprehensive analysis of PH and right heart failure management strategies in the critical care setting. In particular, a unique perspective on oncologically relevant PH is provided.

Inhaled prostacyclin for the prevention of increased pulmonary vascular resistance in cemented hip hemiarthroplasty-A randomised trial

BACKGROUND

Bone cementation may cause pulmonary vasoconstriction and ventilation/perfusion abnormalities in patients undergoing cemented hip hemiarthroplasty. In this randomised trial, we tested the hypothesis that intra-operative inhalation of prostacyclin could attenuate the increase in pulmonary vascular resistance index (PVRI, primary endpoint) when compared to inhaled saline in this group of patients.

METHODS

Twenty-two patients with displaced femoral neck fractures were allocated to receive inhaled aerosolised prostacyclin (20 ng/kg/min) (n = 11) or inhaled saline (NaCl, 9 mg/mL) (n = 11). All patients received total intravenous anaesthesia and were catheterised with radial and pulmonary artery fast response thermodilution catheters, for measurements of arterial and pulmonary arterial pressures, cardiac output, right ventricular ejection fraction and effective pulmonary arterial elastance. Haemodynamic measurements were performed after induction of anaesthesia, during surgery before and immediately after bone cementation and prosthesis insertion, 10 and 20 min after insertion and during skin closure.

RESULTS

During the surgical procedure, PVRI increased both in the saline (44%, P < 0.001) and the prostacyclin (36%, P = 0.019) groups, with a less pronounced increase in the prostacyclin group (P = 0.031). Effective pulmonary arterial elastance increased both in the saline (44%, P < 0.001) and the prostacyclin groups (29%, P = 0.032), with a trend for a less pronounced increase in the prostacyclin group (P = 0.084). Right ventricular ejection fraction decreased significantly in both groups with no difference between the groups.

CONCLUSION

Inhalation of prostacyclin attenuates the increase in pulmonary vascular resistance in patients undergoing cemented hip hemiarthroplasty and could potentially attenuate/prevent haemodynamic instability induced by an increase in right ventricular afterload seen in this procedure.

The Effects of Iloprost on Oxygenation During One-Lung Ventilation for Lung Surgery: A Randomized Controlled Trial

Hypoxemia can occur during one-lung ventilation (OLV) in thoracic surgery, leading to perioperative complications. Inhaled iloprost is a selective pulmonary vasodilator with efficacy in patients with pulmonary hypertension. The purpose of this study was to evaluate the effects of off-label inhaled iloprost on oxygenation during OLV in patients undergoing lung surgery. Seventy-two patients who were scheduled for elective video-assisted thoracoscopic lobectomy were assigned to receive an inhaled nebulizer of distilled water (control group), 10 μg iloprost (IL10 group), or 20 μg iloprost (IL20 group). Arterial and venous blood gas and hemodynamic analyses were obtained. Changes in partial pressure of oxygen in arterial blood (PaO₂), after the initiation of OLV and the resumption two-lung ventilation (TLV), were similar in all three groups. However, PaO₂ in the IL10 group was comparable to that in the control group, whereas PaO₂ in the IL20 group was significantly higher than that in the control group at 10, 20, and 30 min after administration of iloprost (275.1 ± 50.8 vs. 179.3 ± 38.9, p < 0.0001; 233.9 ± 39.7 vs. 155.1 ± 26.5, p < 0.0001; and 224.6 ± 36.4 vs. 144.0 ± 22.9, p < 0.0001, respectively). The shunt fraction in the IL20 group was significantly higher than that in the control group after administration of iloprost (26.8 ± 3.1 vs. 32.2 ± 3.4, p < 0.0001; 24.6 ± 2.2 vs. 29.9 ± 3.4, p < 0.0001; and 25.3 ± 2.0 vs. 30.8 ± 3.1, p < 0.0001, respectively). Administration of inhaled iloprost during OLV improves oxygenation and decreases intrapulmonary shunt.

Practice Variation, Costs and Outcomes Associated with the Use of Inhaled Nitric Oxide in Pediatric Heart Transplant Recipients

Right ventricular (RV) failure is a potentially fatal complication following heart transplantation (HTx). Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator that is used to decrease pulmonary vascular resistance immediately post-HTx to reduce the risk of RV failure. The aim of this study was to describe utilization patterns, costs, and outcomes associated with post-transplant iNO use in children. All pediatric HTx recipients (2002-2016) were identified from a unique linked PHIS/SRTR dataset. Post-HTx iNO use was determined based on hospital billing data. Utilization patterns and associated costs were described. The association of iNO support with post-HTx survival was assessed using the Kaplan-Meier method and a multivariable Cox proportional hazards model was used to adjust for risk factors. A total of 2833 pediatric HTx recipients from 28 centers were identified with 1057 (36.5%) receiving iNO post-HTx. Post-HTx iNO use showed significant increase overall (17.2-54.7%, p < 0.001) and wide variation among centers (9-100%, p < 0.001). Patients with congenital heart disease (aOR 1.4, 95% CI 1.2, 1.6), requiring mechanical ventilation at HTx (aOR 1.3, 95% CI 1.1, 1.6), and pre-transplant iNO (aOR 9.3, 95% CI 5.4, 16) were more likely to receive iNO post-HTx. The median daily cost of iNO was $2617 (IQR $1843-$3646). Patients who required > 5 days of iNO post-HTx demonstrated inferior 1-year post-HTx survival (p < 0.001) and iNO use > 5 days was independently associated with worse post-HTx survival (AHR 1.6, 95% CI 1.2, 2.1; p < 0.001). There is wide variation in iNO use among centers following pediatric HTx with use increasing over time despite significant incremental cost. Prolonged iNO use post-HTx is associated with worse survival, likely serving as a marker of residual illness severity. Further research is needed to define the populations that derive the greatest benefit from this costly therapy.

Perioperative Management of the Cardiac Transplant Recipient

Management of the cardiac transplant recipient includes careful titration of inotropes and vasopressors. Recipient pulmonary hypertension and ventilatory status must be optimized to prevent allograft right ventricular failure. Vasoplegia, coagulopathy, arrhythmias, and renal dysfunction also require careful management to achieve an optimal outcome. Primary graft dysfunction (PGD) can be an ominous problem after cardiac transplantation. Although mild degrees of PGD may be managed medically, mechanical circulatory support with extracorporeal membrane oxygenation or temporary ventricular assist devices may be required. Retransplantation may be necessary in some cases.

Hospital and intensive care unit management of decompensated pulmonary hypertension and right ventricular failure

Pulmonary hypertension and concomitant right ventricular failure present a diagnostic and therapeutic challenge in the intensive care unit and have been associated with a high mortality. Significant co-morbidities and hemodynamic instability are often present, and routine critical care unit resuscitation may worsen hemodynamics and limit the chances of survival in patients with an already underlying poor prognosis. Right ventricular failure results from structural or functional processes that limit the right ventricle’s ability to maintain adequate cardiac output. It is commonly seen as the result of left heart failure, acute pulmonary embolism, progression or decompensation of pulmonary hypertension, sepsis, acute lung injury, or in the perioperative setting. Prompt recognition of the underlying cause and institution of treatment with a thorough understanding of the elements necessary to optimize preload, cardiac contractility, enhance systemic arterial perfusion, and reduce right ventricular afterload are of paramount importance. Moreover, the emergence of previously uncommon entities in patients with pulmonary hypertension (pregnancy, sepsis, liver disease, etc.) and the availability of modern devices to provide support pose additional challenges that must be addressed with an in-depth knowledge of this disease.

Prostacyclins in Cardiac Surgery: Coming of Age

Prostacyclin (prostaglandin I2 [PGI2]) is an eicosanoid lipid mediator produced by the endothelial cells. It plays pivotal roles in vascular homeostasis by virtue of its potent vasodilatory and antithrombotic effects. Stable pharmacological analogues of PGI2 are used for treatment of pulmonary hypertension and right ventricular failure. PGI2 dose dependently inhibits platelet activation induced by adenosine-5′-diphosphate, arachidonic acid, collagen, and low-dose thrombin. This property has led to its use as an alternative to direct thrombin inhibitors in patients with type II heparin-induced thrombocytopenia (HIT) undergoing cardiac surgery. The aims of this review are the following: (1) to review the pharmacology of PGI2 and its derivatives, (2) to present the evidence for their use in pulmonary hypertension and right heart failure, and (3) to discuss their utility in the management of HIT in cardiac surgery.

Aerosolized Vasodilators for the Treatment of Pulmonary Hypertension in Cardiac Surgical Patients: A Systematic Review and Meta-analysis

BACKGROUND

In cardiac surgery, pulmonary hypertension is an important prognostic factor for which several treatments have been suggested over time. In this systematic review and meta-analysis, we compared the efficacy of inhaled aerosolized vasodilators to intravenously administered agents and to placebo in the treatment of pulmonary hypertension during cardiac surgery. We searched MEDLINE, CENTRAL, EMBASE, Web of Science, and clinicaltrials.gov databases from inception to October 2015. The incidence of mortality was assessed as the primary outcome. Secondary outcomes included length of stay in hospital and in the intensive care unit, and evaluation of the hemodynamic profile.

METHODS

Of the 2897 citations identified, 10 studies were included comprising a total of 434 patients.

RESULTS

Inhaled aerosolized agents were associated with a significant decrease in pulmonary vascular resistance (-41.36 dyne·s/cm, P= .03) and a significant increase in mean arterial pressure (8.24 mm Hg, P= .02) and right ventricular ejection fraction (7.29%, P< .0001) when compared to intravenously administered agents. No significant hemodynamically meaningful differences were observed between inhaled agents and placebo; however, an increase in length of stay in the intensive care unit was shown with the use of inhaled aerosolized agents (0.66 days, P= .01). No other differences were observed for either comparison.

CONCLUSIONS

The administration of inhaled aerosolized vasodilators for the treatment of pulmonary hypertension during cardiac surgery is associated with improved right ventricular performance when compared to intravenously administered agents. This review does not support any benefit compared to placebo on major outcomes. Further investigation is warranted in this area of research and should focus on clinically significant outcomes.

Persistent pulmonary hypertension of the newborn

Failure of the normal circulatory adaptation to extrauterine life results in persistent pulmonary hypertension of the newborn (PPHN). Although this condition is most often secondary to parenchymal lung disease or lung hypoplasia, it may also be idiopathic. PPHN is characterized by elevated pulmonary vascular resistance with resultant right-to-left shunting of blood and hypoxemia. Although the preliminary diagnosis of PPHN is often based on differential cyanosis and labile hypoxemia, the diagnosis is confirmed by echocardiography. Management strategies include optimal lung recruitment and use of surfactant in patients with parenchymal lung disease, maintaining optimal oxygenation and stable blood pressures, avoidance of respiratory and metabolic acidosis and alkalosis, and pulmonary vasodilator therapy. Extracorporeal membrane oxygenation is considered when medical management fails. Although mortality associated with PPHN has decreased significantly with improvements in medical care, there remains the potential risk for neurodevelopmental disability which warrants close follow-up of affected infants after discharge.

A retrospective comparison of inhaled milrinone and iloprost in post-bypass pulmonary hypertension

During cardiac operations, weaning from cardiopulmonary bypass (CPB) may prove challenging as a result of superimposed acute right ventricular dysfunction in the setting of elevated pulmonary vascular resistance (PVR). The aim of this study was to retrospectively evaluate the effect of inhaled milrinone versus inhaled iloprost in patients with persistent pulmonary hypertension following discontinuation of CPB. Eighteen patients with elevated PVR post-bypass were administered inhaled milrinone at a cumulative dose of 50 μg kg^-1. These patients were retrospectively matched with 18 patients who were administered 20 μg of inhaled iloprost. Both drugs were administered through a disposable aerosol-generating jet nebulizer device and inhaled for a 15-min period. Hemodynamic measurements were performed before and after cessation of the inhalation period. Both inhaled milrinone and inhaled iloprost induced significant reductions in mean pulmonary artery pressure and PVR and significant increases in cardiac index in patients with post-CPB pulmonary hypertension. The favorable effect of both agents on the pulmonary vasculature was confirmed by echocardiographic measurements. Both agents were devoid of systemic side effects, since mean arterial pressure and systemic vascular resistance were not affected. A decrease in intrapulmonary shunt by inhalation of both agents was also demonstrated. Pulmonary vasodilatation attributed to iloprost seems to be of greater magnitude and of longer duration as compared to that of inhaled milrinone. Both substances proved to be selective pulmonary vasodilators. The greater magnitude and of longer duration vasodilatation attributed to iloprost may be due to its longer duration of action.

Refractory Cardiogenic Shock from Right Ventricular Infarction Successfully Managed with Inhaled Epoprostenol

BACKGROUND Recognition and appropriate management of right ventricular (RV) infarction is essential, as RV injury increases mortality and substantially alters management during acute coronary syndrome. We report a case of RV infarction presenting with new right bundle branch block (RBBB), and therapeutic use of inhaled epoprostenol to reduce RV afterload and augment cardiac output during refractory cardiogenic shock. CASE REPORT A 53-year-old male presented to our institution in ventricular fibrillation with subsequent development of RBBB in the setting of proximal right coronary artery occlusion. Following percutaneous coronary intervention, the patient developed severe RV dysfunction with refractory cardiogenic shock. This was successfully managed with inhaled epoprostenol with normalization of right ventricular systolic function. CONCLUSIONS Although typically associated with anterior myocardial infarction, new RBBB should be recognized as a potential presenting sign of acute RV infarction. The use of inhaled epoprostenol in the setting of RV infarction has not been previously described, but it may augment right ventricular cardiac output via pulmonary vasodilatation.

Postoperative Right Ventricular Failure in Cardiac Surgery

Two cases of patients that developed right ventricular failure (RVF) after cardiac valve surgery are presented with a narrative revision of the literature. RVF involves a great challenge due to the severity of this condition; it has a low incidence among non-congenital cardiac surgery patients, is more likely associated with cardiovascular and pulmonary complications related to cardiopulmonary bypass (CPB), and is a cause of acute graft failure and of a higher early mortality in cardiac transplant. The morphologic and hemodynamic characteristics of the right ventricle and some specific factors that breed pulmonary hypertension after cardiac surgery are in favor of the onset of RVF. Due to the possibility of complications after cardiac valve repair or replacement, measures as appropriate hemodynamic monitoring, to manage oxygenation, ventilation, sedation, acid base equilibrium and perfusion goals are a requirement, as well as a normal circulating volume, and the prevention of a disproportionate rise in the afterload, to preserve the free wall of the right ventricle (RV) and the septum's contribution to the right ventricular global function and geometry. If there is no response to these basic measures, the use of advanced therapy with inotropics, intravenous or inhaled pulmonary vasodilation agents is recommended; the use of mechanical ventricular assistance stands as a last resource.

Managing the Rising Costs and High Drug Expenditures in Critical Care Pharmacy Practice

Pharmaceutical costs for patients in the intensive care unit (ICU) constitute a large portion of hospital drug budgets. Unfortunately, prices for medications commonly used in the ICU are on the rise for a variety of reasons. In particular, the U.S. Food and Drug Administration's Unapproved Drugs Initiative, generic manufacturers cornering the marketplace, drug shortages, and regulatory device changes are major drivers of pharmaceutical price escalation affecting costs in the ICU. Furthermore, traditional high acquisition cost items still pose challenges to controlling costs. To offer strategies to mitigate the rising costs of pharmaceuticals in the ICU setting, we searched the PubMed/Medline and International Pharmaceutical Abstracts databases and other related sources to identify published cost-saving protocols concerning specific medications that are affected by rising prices or have traditional high acquisition costs. In the absence of specific protocols, we offer possible cost-saving initiatives based on published literature regarding specific agents or based on our own diverse set of experiences. Finally, we review suggested clinical and operational activities at an institutional level to address these rising drug costs in the ICU setting.

A prospective, randomized study of inhaled prostacyclin versus nitric oxide in patients with residual pulmonary hypertension after pulmonary endarterectomy

Objectives

Pulmonary endarterectomy (PEA) is an effective treatment for chronic thromboembolic pulmonary hypertension (CTEPH), but postoperative residual hypertension leads to in-hospital mortality. Inhaled epoprostenol sodium (PGI₂) and NO are administered for pulmonary hypertension after cardiothoracic surgery. This prospective study provides the first comparative evaluation of the effects of inhaled PGI₂ and NO on pulmonary hemodynamics, systemic hemodynamics, and gas exchange in patients developing residual pulmonary hypertension after PEA.

Methods

Thirteen patients were randomized to receive either NO (n = 6) or PGI2 (n = 7) inhalation when pulmonary hypertension persisted after weaning from cardiopulmonary bypass. Hemodynamic and respiratory variables were measured before inhalation of the agent (T0); 30 min (T1), 3 h (T2), and 6 h after inhalation (T3); and the next morning (T4). The NO dose was started at 20 ppm and gradually tapered until extubation, and PGI₂ was administered at a dose of 10 ng kg⁻¹ min⁻¹.

Results

In both groups, mean pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) significantly decreased over time until T4 (mean PAP: p < 0.0001; PVR: p = 0.003), while mean systemic arterial blood pressure significantly increased (p = 0.028). There were no significant between-group differences in patient characteristics, cardiac index, left atrial pressure, or ratio of arterial oxygen tension to fraction of inspired oxygen. There were no in-hospital deaths.

Conclusions

Both inhaled PGI₂ and NO significantly reduced PAP and PVR without adverse effects on systemic hemodynamics in patients who developed residual pulmonary hypertension after PEA. Inhaled PGI₂ can be offered as alternative treatment option for residual pulmonary hypertension.

Management of Pulmonary Hypertension in the Operating Room

Pulmonary artery hypertension is defined as persistent elevation of mean pulmonary artery pressure > 25 mm Hg with pulmonary capillary wedge pressure < 15 mm Hg or elevation of exercise mean pulmonary artery pressure > 35 mm Hg. Although mild pulmonary hypertension rarely impacts anesthetic management, severe pulmonary hypertension and exacerbation of moderate hypertension can lead to acute right ventricular failure and cardiogenic shock. Knowledge of anesthetic drug effects on the pulmonary circulation is essential for anesthesiologists. Intraoperative management should include prevention of exacerbating factors such as hypoxemia, hypercarbia, acidosis, hypothermia, hypervolemia, and increased intrathoracic pressure; monitoring and optimizing right ventricular function; and treatment with selective pulmonary vasodilators. Recent advances in pharmacology provide anesthesiologists with a wide variety of options for selective pulmonary vasodilatation. Pulmonary hypertension is a major determinant of perioperative morbidity and mortality in special situations such as heart and lung transplantation, pneumonectomy, and ventricular assist device placement.

High-flow oxygen therapy and other inhaled therapies in intensive care units

In this Series paper, we review the current evidence for the use of high-flow oxygen therapy, inhaled gases, and aerosols in the care of critically ill patients. The available evidence supports the use of high-flow nasal cannulae for selected patients with acute hypoxaemic respiratory failure. Heliox might prevent intubation or improve gas flow in mechanically ventilated patients with severe asthma. Additionally, it might improve the delivery of aerosolised bronchodilators in obstructive lung disease in general. Inhaled nitric oxide might improve outcomes in a subset of patients with postoperative pulmonary hypertension who had cardiac surgery; however, it has not been shown to provide long-term benefit in patients with acute respiratory distress syndrome (ARDS). Inhaled prostacyclins, similar to inhaled nitric oxide, are not recommended for routine use in patients with ARDS, but can be used to improve oxygenation in patients who are not adequately stabilised with traditional therapies. Aerosolised bronchodilators are useful in mechanically ventilated patients with asthma and chronic obstructive pulmonary disease, but are not recommended for those with ARDS. Use of aerosolised antibiotics for ventilator-associated pneumonia and ventilator-associated tracheobronchitis shows promise, but the delivered dose can be highly variable if proper attention is not paid to the delivery method.

Pharmacologic strategies in neonatal pulmonary hypertension other than nitric oxide

Inhaled nitric oxide (iNO) is approved for use in persistent pulmonary hypertension of the newborn (PPHN) but does not lead to sustained improvement in oxygenation in one-third of patients with PPHN. Inhaled NO is less effective in the management of PPHN secondary to congenital diaphragmatic hernia (CDH), extreme prematurity, and bronchopulmonary dysplasia (BPD). Intravenous pulmonary vasodilators such as prostacyclin, alprostadil, sildenafil, and milrinone have been successfully used in PPHN resistant to iNO. Oral pulmonary vasodilators such as endothelin receptor antagonist bosentan and phosphodiesterase-5 inhibitors such as sildenafil and tadalafil are used both during acute and chronic phases of PPHN. In the absence of infection, glucocorticoids may also be effective in PPHN. Many of these pharmacologic agents are not approved for use in PPHN and our knowledge is based on case reports and small trials. Large multicenter randomized controlled trials with long-term follow-up are required to evaluate alternate pharmacologic strategies in PPHN.

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.