Arterial pulmonary hypertension in noncardiac intensive care unit

The sine transform is the sine qua non of the pulmonary and systemic pressure relationship

Assessment of therapeutic interventions in patients with pulmonary arterial hypertension (PAH) suffers from several commonly encountered limitations: (1) patient studies are often too small and short-term to provide definitive conclusions, (2) there is a lack of a universal set of metrics to adequately assess therapy and (3) while clinical treatments focus on management of symptoms, there remain many cases of early loss of life in a seemingly arbitrary distribution. Here we provide a unified approach to assess right and left pressure relationships in PAH and pulmonary hypertension (PH) patients by developing linear models informed by the observation of Suga and Sugawa that pressure generation in the ventricle (right or left) approximately follows a single lobe of a sinusoid. We sought to identify a set of cardiovascular variables that either linearly or via a sine transformation related to systolic pulmonary arterial pressure (PAPs) and systemic systolic blood pressure (SBP). Importantly, both right and left cardiovascular variables are included in each linear model. Using non-invasively obtained cardiovascular magnetic resonance (CMR) image metrics the approach was successfully applied to model PAPs in PAH patients with an r2 of 0.89 (p < 0.05) and SBP with an r2 of 0.74 (p < 0.05). Further, the approach clarified the relationships that exist between PAPs and SBP separately for PAH and PH patients, and these relationships were used to distinguish PAH vs. PH patients with good accuracy (68%, p < 0.05). An important feature of the linear models is that they demonstrate that right and left ventricular conditions interact to generate PAPs and SBP in PAH patients, even in the absence of left-sided disease. The models predicted a theoretical right ventricular pulsatile reserve that in PAH patients was shown to be predictive of the 6 min walk distance (r2 = 0.45, p < 0.05). The linear models indicate a physically plausible mode of interaction between right and left ventricles and provides a means of assessing right and left cardiac status as they relate to PAPs and SBP. The linear models have potential to allow assessment of the detailed physiologic effects of therapy in PAH and PH patients and may thus permit cross-over of knowledge between PH and PAH clinical trials.

Obstructive Shock, from Diagnosis to Treatment

Shock is a life threatening pathological condition characterized by inadequate tissue oxygen supply. Four different subgroups of shock have been proposed according to the mechanism causing the shock. Of these, obstructive shock is characterized by reduction in cardiac output due to noncardiac diseases. The most recognized causes include pulmonary embolism, tension pneumothorax, pericardial tamponade and aortic dissection. Since obstructive shock typically cannot be stabilized unless cause for shock is resolved, diagnosis of the underlying disease is eminent. In this review, we therefore focus on diagnosis of obstructive shock and suggest a structured approach in three steps including clinical examination, ultrasound examination using the rapid ultrasound in shock (RUSH) protocol and radiological imaging if needed.

Challenges in managing a critically ill patient with decompensated Eisenmenger syndrome

Eisenmenger syndrome (ES) is the most severe form of pulmonary arterial hypertension and is associated with congenital heart disease. ES itself is a challenging condition to manage, further compounded if the patient is critically ill and acutely decompensated. We share our experience of managing a critically ill adult patient with ES who presented with acute decompensation due to sepsis.

Demographics and Risk Factors of Pediatric Pulmonary Hypertension Readmissions

BACKGROUND AND OBJECTIVES

Pulmonary hypertension (PH) leads to significant morbidity and mortality in pediatric patients and increases the readmission rates for hospitalizations. This study evaluates the risk factors and comorbidities associated with an increase in 30-day readmissions among pediatric PH patients.

METHODS

National Readmission Database (NRD) 2017 was searched for patients less than 18 years of age who were diagnosed with PH based on the International Classification of Diseases, 10th Revision (ICD-10). Statistical Package for the Social Sciences (SPSS) software v25.0 (IBM Corp., Armonk, NY) was used for statistical analysis.

RESULTS

Of 5.52 million pediatric encounters, 10,501 patients met the selection criteria. The 30-day readmission rate of 14.43% (p < 0.001) was higher than hospitalizations from other causes {Odds Ratio (OR) 4.02 (3.84-4.20), p < 0.001}. The comorbidities of sepsis {OR 0.75 (0.64-0.89), p < 0.02} and respiratory infections {OR 0.75 (0.67-0.85), p < 0.001} were observed to be associated with lower 30-day readmissions. Patients who required invasive mechanical ventilation via endotracheal tube {OR 1.66 (1.4-1.96), p < 0.001} or tracheostomy tube {OR 1.35 (1.15-1.6), p < 0.001} had increased unplanned readmissions. Patients with higher severity of illness based on All Patients Refined Diagnosis Related Groups (APR-DRG) were more likely to get readmitted {OR 7.66 (3.13-18.76), p < 0.001}.

CONCLUSION

PH was associated with increased readmission rates compared to the other pediatric diagnoses, but the readmission rate in this study was lower than one previous pediatric study. Invasive mechanical ventilation, Medicaid insurance, higher severity of illness, and female gender were associated with a higher likelihood of readmission within 30 days.

Inhaled high dose nitric oxide is a safe and effective respiratory treatment in spontaneous breathing hospitalized patients with COVID-19 pneumonia

BACKGROUND

Inhaled nitric oxide (NO) is a selective pulmonary vasodilator. In-vitro studies report that NO donors can inhibit replication of SARS-CoV-2. This multicenter study evaluated the feasibility and effects of high-dose inhaled NO in non-intubated spontaneously breathing patients with Coronavirus disease-2019 (COVID-19).

METHODS

This is an interventional study to determine whether NO at 160 parts-per-million (ppm) inhaled for 30 min twice daily might be beneficial and safe in non-intubated COVID-19 patients.

RESULTS

Twenty-nine COVID-19 patients received a total of 217 intermittent inhaled NO treatments for 30 min at 160 ppm between March and June 2020. Breathing NO acutely decreased the respiratory rate of tachypneic patients and improved oxygenation in hypoxemic patients. The maximum level of nitrogen dioxide delivered was 1.5 ppm. The maximum level of methemoglobin (MetHb) during the treatments was 4.7%. MetHb decreased in all patients 5 min after discontinuing NO administration. No adverse events during treatment, such as hypoxemia, hypotension, or acute kidney injury during hospitalization occurred. In our NO treated patients, one patient of 29 underwent intubation and mechanical ventilation, and none died. The median hospital length of stay was 6 days [interquartile range 4-8]. No discharged patients required hospital readmission nor developed COVID-19 related long-term sequelae within 28 days of follow-up.

CONCLUSIONS

In spontaneous breathing patients with COVID-19, the administration of inhaled NO at 160 ppm for 30 min twice daily promptly improved the respiratory rate of tachypneic patients and systemic oxygenation of hypoxemic patients. No adverse events were observed. None of the subjects was readmitted or had long-term COVID-19 sequelae.

Advanced airway management and respiratory care in decompensated pulmonary hypertension

Meticulous risk stratification is essential when considering intubation of a patient with decompensated pulmonary hypertension (dPH). It is paramount to understand both the pathophysiology of dPH (and associated right ventricular failure) and the complications related to a high-risk intubation before attempting the procedure. There are few recommendations in this area and the literature, guiding these recommendations, is limited to expert opinion and very few case reports/case series. This review will discuss the complex pathophysiology of dPH, the complications associated with intubation, the debates surrounding induction agents, and the available options for the intubation procedure, with specific emphasis on the emerging role for awake fiberoptic intubation. All patients should be evaluated for candidacy for veno-arterial extracorporeal membrane oxygen as a bridge to recovery, lung transplantation, or pulmonary endarterectomy prior to intubation. Only an experienced proceduralist who is both comfortable with high-risk intubations and the pathophysiology of dPH should perform these intubations.

The contemporary pulmonary artery catheter. Part 2: measurements, limitations, and clinical applications

Nowadays, the classical pulmonary artery catheter (PAC) has an almost 50-year-old history of its clinical use for hemodynamic monitoring. In recent years, the PAC evolved from a device that enabled intermittent cardiac output measurements in combination with static pressures to a monitoring tool that provides continuous data on cardiac output, oxygen supply and-demand balance, as well as right ventricular performance. In this review, which consists of two parts, we will introduce the difference between intermittent pulmonary artery thermodilution using bolus injections, and the contemporary PAC enabling continuous measurements by using a thermal filament which heats up the blood. In this second part, we will discuss in detail the measurements of the contemporary PAC, including continuous cardiac output measurement, right ventricular ejection fraction, end-diastolic volume index, and mixed venous oxygen saturation. Limitations of all of these measurements are highlighted as well. We conclude that thorough understanding of measurements obtained from the PAC is the first step in successful application of the PAC in daily clinical practice.

Atrial fibrillation in COVID-19: A review of possible mechanisms

A relationship between COVID-19 infection and an increasing incidence of atrial fibrillation has been observed. However, the underlying pathophysiology as a precipitant to AF has not been reviewed. This paper will consider the possible pathological and immunological AF mechanisms as a result, of COVID-19 infection. We discuss the role myocardial microvascular pericytes expressing the ACE-2 receptor and their potential for an organ-specific cardiac involvement with COVID-19. Dysfunctional microvascular support by pericytes or endothelial cells may increase the propensity for AF via increased myocardial inflammation, fibrosis, increased tissue edema, and interstitial hydrostatic pressure. All of these factors can lead to electrical perturbances at the tissue and cellular level. We also consider the contribution of Angiotensin, pulmonary hypertension, and regulatory T cells as additional contributors to AF during COVID-19 infection. Finally, reference is given to two common drugs, corticosteroids and metformin, in COVID-19 and how they might influence AF incidence.

Anesthesia for Pregnant Women with Pulmonary Hypertension

Despite advances in the therapy for pulmonary hypertension over the past decades, the prognosis of pregnant patients with pulmonary hypertension remains poor, with high maternal mortality. This poses a particular challenge for the mother and her medical team. In the present review, the authors have updated the classification and definition of pulmonary hypertension, summarized the current knowledge with regard to perioperative management and anesthesia considerations for these patients, and stressed the importance of a "pregnancy heart team" to improve long-term outcomes of pregnant women with pulmonary hypertension.

Pulmonary Hypertension by the Method of Paul Wood

A physiological approach to the analysis of hemodynamic data in pulmonary hypertension (PH) has the advantage of reducing the large number (well over 100) of potential causal illnesses into four simple mechanisms. A fifth condition is composed of mixtures of the four basic mechanisms. This approach was beautifully described by Paul Wood, the great cardiologist whose name is given to the units of pulmonary vascular resistance (PVR), Wood units. This approach uses well understood physiological contributions to pulmonary vascular pressure. It is powerful, the major uncertainty being in determination of the magnitude of each mechanism in patients that have mixed PH of several causes. It also makes sense of the occasionally awkward clustering of conditions in the clinical classification of the World Symposium, which omits pulmonary vasoconstriction, hyperkinetic states, and the highly prevalent condition of "mixed" PH. This method of analysis is described and demonstrated, much as Wood did in his writings. The method is useful in the office, the ICU, and in consultation. A basic message from this approach is that correct assessment requires measurement of each of the three major inputs, pulmonary arterial pressure (Ppa), pulmonary artery wedge pressure (Pwedge) and cardiac output (CO). Some cases also need left ventricular end diastolic pressure (LVEDP). Other data contributing to analysis will be discussed in each condition. A key to avoiding mistakes is to always remember that PH is simply an elevation in pressure and is not inherently diagnostic of cause.

Right Heart Function in Critically Ill Patients at Risk for Acute Right Heart Failure: A Description of Right Ventricular-Pulmonary Arterial Coupling, Ejection Fraction and Pulmonary Artery Pulsatility Index

BACKGROUND

The gold standard for right heart function is the assessment of right ventricular-pulmonary arterial coupling defined as the ratio of arterial to end-systolic elastance (Ea/Emax). This study demonstrates the use of the volumetric pulmonary artery (PA) catheter for estimation of Ea/Emax and describes trends of Ea/Emax, right ventricular ejection fraction (RVEF), and pulmonary artery pulsatility index (PAPi) during initial 48hours of resuscitation in the trauma surgical intensive care unit (ICU).

METHODS

Review of prospectively collected data for 32 mechanically ventilated adult trauma and emergency general surgery patients enrolled within 6hours of admission to the ICU. Haemodynamics, recorded every 12hours for 48hours, were compared among survivors and non-survivors to hospital discharge.

RESULTS

Mean age was 49±20 years, 69% were male, and 84% were trauma patients. Estimated Ea/Emax was associated with pulmonary vascular resistance and inversely related to pulmonary arterial capacitance and PA catheter derived RVEF. Seven (7) trauma patients did not survive to hospital discharge. Non-survivors had higher estimated Ea/Emax, suggesting right ventricular-pulmonary arterial uncoupling, with a statistically significant difference at 48hours (2.3±1.7 vs 1.0±0.58, p=0.018). RVEF was significantly lower in non-survivors at study initiation and at 48hours. PAPi did not show a consistent trend.

CONCLUSIONS

Estimation of Ea/Emax using volumetric PA catheter is feasible. Serial assessment of RVEF and Ea/Emax may help in early identification of right heart dysfunction in critically ill mechanically ventilated patients at risk for acute right heart failure.

Dynamic changes of pulmonary arterial pressure in perinatal neonates with pulmonary and extrapulmonary acute lung injury/respiratory distress syndrome

This study aims to explore the dynamic changes of pulmonary arterial pressure (PAP) and its clinical significance in prenatal neonates with pulmonary and extra-pulmonary acute lung injury/respiratory distress syndrome (ALI/ARDS).A prospective study was conducted in the Neonate Intensive Care Unit (NICU) between May 2015 and April 2017. A total of 78 prenatal neonates with ALI/ARDS were selected and divided into 2 groups: pulmonary group (n = 37) and extra-pulmonary group (n = 41). These neonates were further divided into 3 groups according to the OSI index: mild, moderate, and severe groups. The dynamic changes of PAP were observed in these neonates. In the moderate and severe groups, PAP was significantly higher in neonates with pulmonary ALI/ADDS (ALI/ARDSp) than in neonates with extrapulmonary ALI/ARDS(ALI/ARDSexp) (62.5 ± 5.4 vs 68.0 ± 6.5, 54.7 ± 5.9 vs 64.2 ± 4.9; t = 3.264, 3.123; P = .004,.039). Furthermore, PAP was higher in neonates with ALI/ADDSp in the severe group, compared with those in the moderate group (t = 2.420, P < .05). There was significant difference among the 3 subgroups of neonates with ALI/ADDSexp (F = 60.100, P = .000). PAP was positively correlated with the OSI index (r = 0.823). The overall dynamic PAP monitoring results revealed that PAP was higher in the pulmonary group than that in the extrapulmonary group, and this exhibited a gradually decreasing trend as the condition of the subject improved.PAP in perinatal neonates with ALI/ARDS increases in varying degrees, and its extent was related to the severity of the illness. PAP was significantly higher in neonates with ALI/ADDSp than in neonates with ALI/ADDSexp. This can be used as a monitoring indicator for the severity of illness.

Diagnostic workup, etiologies and management of acute right ventricle failure : A state-of-the-art paper

INTRODUCTION

This is a state-of-the-art article of the diagnostic process, etiologies and management of acute right ventricular (RV) failure in critically ill patients. It is based on a large review of previously published articles in the field, as well as the expertise of the authors.

RESULTS

The authors propose the ten key points and directions for future research in the field. RV failure (RVF) is frequent in the ICU, magnified by the frequent need for positive pressure ventilation. While no universal definition of RVF is accepted, we propose that RVF may be defined as a state in which the right ventricle is unable to meet the demands for blood flow without excessive use of the Frank-Starling mechanism (i.e. increase in stroke volume associated with increased preload). Both echocardiography and hemodynamic monitoring play a central role in the evaluation of RVF in the ICU. Management of RVF includes treatment of the causes, respiratory optimization and hemodynamic support. The administration of fluids is potentially deleterious and unlikely to lead to improvement in cardiac output in the majority of cases. Vasopressors are needed in the setting of shock to restore the systemic pressure and avoid RV ischemia; inotropic drug or inodilator therapies may also be needed. In the most severe cases, recent mechanical circulatory support devices are proposed to unload the RV and improve organ perfusion CONCLUSION: RV function evaluation is key in the critically-ill patients for hemodynamic management, as fluid optimization, vasopressor strategy and respiratory support. RV failure may be diagnosed by the association of different devices and parameters, while echocardiography is crucial.

Optimal right heart filling pressure in acute respiratory distress syndrome determined by strain echocardiography

INTRODUCTION

Right ventricular (RV) systolic dysfunction is common in acute respiratory distress syndrome (ARDS). While preload optimization is crucial in its management, dynamic fluid responsiveness indices lack reliability, and there is no consensus on target central venous pressure (CVP). We analyzed the utility of RV free wall longitudinal strain (RVFWS) in the estimation of optimal RV filling pressure in ARDS.

METHODS

A retrospective cross-sectional analysis of clinical data and echocardiograms of patients with ARDS was performed. Tricuspid annular plane systolic excursion (TAPSE), tricuspid peak systolic velocity (S'), RV fractional area change (RVFAC), RVFWS, CVP, systolic pulmonary artery pressure (SPAP), and left ventricular ejection fraction (LVEF) were measured.

RESULTS

Fifty-one patients with moderate-severe ARDS were included. There were inverse correlations between CVP and TAPSE, S', RVFAC, RVFWS, and LVEF. The most significant was with RVFWS (r:.74, R² :.55, P:.00001). Direct correlations with creatinine and lactate were noted. Receiver operating characteristic analysis showed that RVFWS -21% (normal reference value) was associated with CVP: 13 mm Hg (AUC: 0.92, 95% CI: 0.83-1.00). Regression model analysis of CVP, and RVFWS interactions established an RVFWS range from -18% to -24%. RVFWS -24% corresponded to CVP: 11 mm Hg and RVFWS -18% to CVP: 15 mm Hg. Beyond a CVP of 15 mm Hg, biventricular systolic dysfunction rapidly ensues.

CONCLUSIONS

Our data are the first to show that an RV filling pressure of 13±2 mm Hg-as by CVP-correlates with optimal RV mechanics as evaluated by strain echocardiography in patients with moderate-severe ARDS.

Endogenous PGI2 signaling through IP inhibits neutrophilic lung inflammation in LPS-induced acute lung injury mice model

Endogenous prostaglandin I₂ (PGI₂) has inhibitory effects on immune responses against pathogens or allergens; however, the immunomodulatory activity of endogenous PGI₂ signaling in endotoxin-induced inflammation is unknown. To test the hypothesis that endogenous PGI₂ down-regulates endotoxin-induced lung inflammation, C57BL/6 wild type (WT) and PGI₂ receptor (IP) KO mice were challenged intranasally with LPS. Urine 6-keto-PGF_1α, a stable metabolite of PGI_2, was significantly increased following the LPS-challenge, suggesting that endogenous PGI₂ signaling modulates the host response to LPS-challenge. IPKO mice had a significant increase in neutrophils in the BAL fluid as well as increased proteins of KC, LIX, and TNF-α in lung homogenates compared with WT mice. In contrast, IL-10 was decreased in LPS-challenged IPKO mice compared with WT mice. The PGI₂ analog cicaprost significantly decreased LPS-induced KC, and TNF-α, but increased IL-10 and AREG in bone marrow-derived dendritic cells (BMDCs) and bone marrow-derived macrophages (BMMs) compared with vehicle-treatment. These results indicated that endogenous PGI₂ signaling attenuated neutrophilic lung inflammation through the reduced inflammatory cytokine and chemokine and enhanced IL-10.

Anesthetics and Outcome in Status Epilepticus: A Matched Two-Center Cohort Study

BACKGROUND

The use of anesthetics has been linked to poor outcome in patients with status epilepticus (SE). This association, however, may be confounded, as anesthetics are mostly administered in patients with more severe SE and critical illnesses.

OBJECTIVE

To minimize treatment-selection bias, we assessed the association between continuously administered intravenous anesthetic drugs (IVADs) and outcome in SE patients by a matched two-center study design.

METHODS

This cohort study was performed at the Johns Hopkins Bayview Medical Center, Baltimore, MD, USA and the University Hospital Basel, Basel, Switzerland. All consecutive adult SE patients from 2005 to 2013 were included. Odds ratios (ORs) for death and unfavorable outcome (Glasgow Outcome Score [GOS] 1-3) associated with administration of IVADs were calculated. To account for confounding by known outcome determinants (age, level of consciousness, worst seizure type, acute/fatal etiology, mechanical ventilation, and SE duration), propensity score matching and coarsened exact matching were performed in addition to multivariable regression models.

RESULTS

Among 406 consecutive patients, 139 (34.2%) were treated with IVADs. Logistic regression analyses of the unmatched and matched cohorts revealed increased odds for death and unfavorable outcome in survivors who had received IVADs (unmatched: OR_death = 3.13, 95% confidence interval [CI] 1.47-6.60 and OR_GOS1-3 = 2.51, 95% CI 1.37-4.60; propensity score matched: OR_death = 3.29, 95% CI 1.35-8.05 and OR_GOS1-3 = 2.27, 95% CI 1.02-5.06; coarsened exact matched: OR_death = 2.19, 95% CI 1.27-3.78 and OR_GOS1-3 = 3.94, 95% CI 2.12-7.32).

CONCLUSION

The use of IVADs in SE is associated with death and unfavorable outcome in survivors independent of known confounders and using different statistical approaches. Randomized trials are needed to determine if these associations are biased by outcome predictors not yet identified and hence not accounted for in this study.

Pulmonary Hypertension an Independent Risk Factor for Death in Intensive Care Unit: Correlation of Hemodynamic Factors with Mortality

OBJECTIVE

Critically ill patients with pulmonary hypertension (PH) pose additional challenges due to the existence of right ventricular (RV) dysfunction. The purpose of this study was to assess the impact of hemodynamic factors on the outcome.

METHODS

We reviewed the records of patients with a diagnosis of PH admitted to the intensive care unit. In addition to evaluating traditional hemodynamic parameters, we defined severe PH as right atrial pressure >20 mmHg, mean pulmonary artery pressure >55 mmHg, or cardiac index (CI) <2 L/min/m². We also defined the RV functional index (RFI) as pulmonary artery systolic pressure (PASP) adjusted for CI as PASP/CI; increasing values reflect RV dysfunction.

RESULTS

Fifty-three patients (mean age 60 years, 72% women, 79% Blacks), were included in the study. Severe PH was present in 68% of patients who had higher Sequential Organ Failure Assessment (SOFA) score (6.8 ± 3.3 vs 3.8 ± 1.6; P = 0.001) and overall in-hospital mortality (36% vs 6%; P = 0.02) compared to nonsevere patients, although Acute Physiology and Chronic Health Evaluation (APACHE) II scores (19.9 ± 7.5 vs 18.5 ± 6.04; P = 0.52) were similar and sepsis was more frequent among nonsevere PH patients (31 vs 64%; P = 0.02). Severe PH (P = 0.04), lower mean arterial pressure (P = 0.04), and CI (P = 0.01); need for invasive ventilation (P = 0.02) and vasopressors (P = 0.03); and higher SOFA (P = 0.001), APACHE II (P = 0.03), pulmonary vascular resistance index (PVRI) (P = 0.01), and RFI (P = 0.004) were associated with increased mortality. In a multivariate model, SOFA [OR = 1.45, 95% confidence interval (C.I.) = 1.09–1.93; P = 0.01], PVRI (OR = 1.12, 95% C.I. = 1.02–1.24; P = 0.02), and increasing RFI (OR = 1.06, 95% C.I. = 1.01–1.11; P = 0.01) were independently associated with mortality.

CONCLUSION

PH is an independent risk factor for mortality in critically ill patients. Composite factors rather than individual hemodynamic parameters are better predictors of outcome. Monitoring of RV function using composite hemodynamic factors resulting in specific interventions is likely to improve survival and needs to be studied further.

Vasoconstrictor responses to vasopressor agents in human pulmonary and radial arteries: an in vitro study

BACKGROUND

Vasopressor drugs, commonly used to treat systemic hypotension and maintain organ perfusion, may also induce regional vasoconstriction in specialized vascular beds such as the lung. An increase in pulmonary vascular tone may adversely affect patients with pulmonary hypertension or right heart failure. While sympathomimetics constrict pulmonary vessels, and vasopressin does not, a direct comparison between these drugs has not been made. This study investigated the effects of clinically used vasopressor agents on human isolated pulmonary and radial arteries.

METHODS

Isolated pulmonary and radial artery ring segments, mounted in organ baths, were used to study the contractile responses of each vasopressor agent. Concentration-response curves to norepinephrine, phenylephrine, metaraminol, and vasopressin were constructed.

RESULTS

The sympathomimetics norepinephrine, phenylephrine, and metaraminol caused concentration-dependent vasoconstriction in the radial (pEC50: 6.99 ± 0.06, 6.14 ± 0.09, and 5.56 ± 0.07, respectively, n = 4 to 5) and pulmonary arteries (pEC50: 6.86 ± 0.11, 5.94 ± 0.05 and 5.56 ± 0.09, respectively, n = 3 to 4). Vasopressin was a potent vasoconstrictor of the radial artery (pEC50 9.13 ± 0.20, n = 3), whereas in the pulmonary artery, it had no significant effect.

CONCLUSIONS

Sympathomimetic-based vasopressor agents constrict both human radial and pulmonary arteries with similar potency in each. In contrast, vasopressin, although a potent vasoconstrictor of radial vessels, had no effect on pulmonary vascular tone. These findings provide some support for the use of vasopressin in patients with pulmonary hypertension.

Peptide-coated liposomal fasudil enhances site specific vasodilation in pulmonary arterial hypertension

This study sought to develop a liposomal delivery system of fasudil—an investigational drug for the treatment of pulmonary arterial hypertension (PAH)—that will preferentially accumulate in the PAH lungs. Liposomal fasudil was prepared by film-hydration method, and the drug was encapsulated by active loading. The liposome surface was coated with a targeting moiety, CARSKNKDC, a cyclic peptide; the liposomes were characterized for size, polydispersity index, zeta potential, and storage and nebulization stability. The in vitro drug release profiles and uptake by TGF-β activated pulmonary arterial smooth muscle cells (PASMC) and alveolar macrophages were evaluated. The pharmacokinetics were monitored in male Sprague–Dawley rats, and the pulmonary hemodynamics were studied in acute and chronic PAH rats. The size, polydispersity index (PDI), and zeta potential of the liposomes were 206–216 nm, 0.058–0.084, and −20–42.7 mV, respectively. The formulations showed minimal changes in structural integrity when nebulized with a commercial microsprayer. The optimized formulation was stable for >4 weeks when stored at 4 °C. Fasudil was released in a continuous fashion over 120 h with a cumulative release of 76%. Peptide-linked liposomes were taken up at a higher degree by TGF-β activated PASMCs; but alveolar macrophages could not engulf peptide-coated liposomes. The formulations did not injure the lungs; the half-life of liposomal fasudil was 34-fold higher than that of plain fasudil after intravenous administration. Peptide-linked liposomal fasudil, as opposed to plain liposomes, reduced the mean pulmonary arterial pressure by 35–40%, without influencing the mean systemic arterial pressure. This study establishes that CAR-conjugated inhalable liposomal fasudil offers favorable pharmacokinetics and produces pulmonary vasculature specific dilatation.

Pulmonary Arterial Hypertension in Intensive Care Unit

For the intensive care unit (ICU) physician, the diagnosis of pulmonary arterial hypertension (PAH) is difficult as it can easily be confounded with other forms of pulmonary hypertension (PH). The key issue is that PAH is a form of PH. On the opposite, PH does not automatically imply PAH. Pulmonary arterial hypertension must be differentiated from other causes of PH that are frequently seen in ICU. It was recently emphasized that pulmonary veno-occlusive disease (PVOD) must be differentiated from PH and PAH. The prognosis of PAH was consistently improved in the ten past years by introduction of selective pulmonary vasodilators and management by highly specialized medical teams. In ICU patients, PAH remains a severe disease with a high mortality rate. When PAH is suspected, a systematic diagnosis approach is of particular importance in order to rapidly eliminate left cardiac, thromboembolic and pulmonary causes of PH. Left cardiac disease is the most common cause of PH. Early recognition of PAH allows a rapid introduction of selective pulmonary vasodilators that can improve outcome. Idiopathic PAH is the most frequent cause but it can also be associated with scleroderma, HIV infection, anorexigen toxicity, thyroid disease, cirrhosis. Pulmonary vasodilators should be only a part of a general management including treatment of triggering factors, optimization of fluid balance, decrease of RV afterload by using pulmonary vasodilators while maintaining cardiac output and mean arterial pressure. The early contact of PH referral center or specialized physician is of particular importance.

Third-line antiepileptic therapy and outcome in status epilepticus: the impact of vasopressor use and prolonged mechanical ventilation

OBJECTIVES

To characterize associations between antiepileptic drugs with sedating or anesthetic effects (third-line antiepileptic drugs) vs. other antiepileptic agents, and short-term outcomes, in status epilepticus. Furthermore, to evaluate the role of adverse hemodynamic and respiratory effects of these agents in status epilepticus treatment.

DESIGN

Retrospective comparative analysis.

SETTING

Tertiary academic medical center with two emergency departments and two neurologic intensive care units.

PATIENTS

Adults admitted with a diagnosis of status epilepticus defined as seizures lasting continuously >5 mins, or for discrete periods in succession.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 126 patients with 144 separate status epilepticus admissions, 57 were female (45%) with mean age 54.7 ± 15.7 yrs. Status epilepticus was convulsive in 132 cases (92%). Status epilepticus etiologies included subtherapeutic antiepileptic drugs (43%), alcohol or other nonantiepileptic drug (13%), and acute central nervous system disease (12%). Third-line antiepileptic drugs were administered in 47 cases (33%). Seventy-eight status epilepticus episodes (54%) had good outcomes (Glasgow Outcome Score = 1, 2) at the time of hospital discharge. On univariate analysis, poor outcome (Glasgow Outcome Score > 2) was associated with older age (mean 59.8 ± 15.5 vs. 50.5 ± 13.8 yrs, p < .001), acute central nervous system disease (21% vs. 4%, p = .001), mechanical ventilation (76% vs. 53%, p = .004), longer duration of ventilation (median 10 days [range 1-56] vs. 2 days [range 1-10], p < .001), treatment with vasopressors (35% vs. 5%, p < .001), and treatment with third-line antiepileptic drugs (51% vs. 17%, p < .001). Death was associated with acute central nervous system disease, prolonged ventilation, treatment with vasopressors, and treatment with third-line antiepileptic drugs. Predictors of poor outcome among all status epilepticus episodes were older age (odds ratio 1.06; 95% confidence interval 1.03-1.09; p < .001), treatment with third-line antiepileptic therapy (odds ratio 5.64; 95% confidence interval 2.31-13.75; p < .001), and first episode of status epilepticus (odds ratio 3.73; 95% confidence interval 1.38-10.10; p = .010). Among status epilepticus episodes treated by third-line antiepileptic drugs, predictors of poor outcome were older age (odds ratio, 1.09; 95% confidence interval 1.01-1.18; p = .038) and longer ventilation (odds ratio, 1.47; 95% confidence interval 1.08-2.00; p = .015). Predictors of mortality among all status epilepticus episodes were treatment with third-line antiepileptic drugs (odds ratio, 12.08; 95% confidence interval 2.30-63.39; p = .003) and older age (odds ratio, 1.06; 95% confidence interval 1.00-1.12; p = .045).

CONCLUSIONS

Third-line antiepileptic drug therapies with sedating or anesthetic effects predicted poor outcome and death in status epilepticus. Hypotension requiring vasopressor therapy and duration of mechanical ventilation induced by these agents may be contributing factors, especially when pentobarbital is used. These findings may inform decision making on drug therapy in status epilepticus and help develop safer and more effective treatment strategies to improve outcome.

Pulmonary hypertension in pregnancy: critical care management

Pulmonary hypertension is common in critical care settings and in presence of right ventricular failure is challenging to manage. Pulmonary hypertension in pregnant patients carries a high mortality rates between 30-56%. In the past decade, new treatments for pulmonary hypertension have emerged. Their application in pregnant women with pulmonary hypertension may hold promise in reducing morbidity and mortality. Signs and symptoms of pulmonary hypertension are nonspecific in pregnant women. Imaging workup may have undesirable radiation exposure. Pulmonary artery catheter remains the gold standard for diagnosing pulmonary hypertension, although its use in the intensive care unit for other conditions has slowly fallen out of favor. Goal-directed bedside echocardiogram and lung ultrasonography provide attractive alternatives. Basic principles of managing pulmonary hypertension with right ventricular failure are maintaining right ventricular function and reducing pulmonary vascular resistance. Fluid resuscitation and various vasopressors are used with caution. Pulmonary-hypertension-targeted therapies have been utilized in pregnant women with understanding of their safety profile. Mainstay therapy for pulmonary embolism is anticoagulation, and the treatment for amniotic fluid embolism remains supportive care. Multidisciplinary team approach is crucial to achieving successful outcomes in these difficult cases.

Pulmonary hypertension in critical care

PURPOSE OF REVIEW

To review the contemporary management of patients with pulmonary hypertension in critical care.

RECENT FINDINGS

The normal mean pulmonary artery pressure (mPAP) at rest is 14±3  mmHg and pulmonary hypertension is considered when mPAP is greater than or equal to 25  mmHg at rest. The classification of pulmonary hypertension has been redefined recently and updated in 2009 and could help to guide the management of patients with pulmonary hypertension in critical care. The management of pulmonary hypertension in ICU is based on expert opinion. Among the diagnostic and monitoring tools available, echocardiography provides useful information noninvasively, although pulmonary artery catheter must be used in case of complicated situations. Calcium sensitizers, a new class of inotrope, have inotropic effects and induce dilatation of the pulmonary, systemic, and coronary vasculature and thus could be useful in case of right ventricular failure (RVF), particularly in patients with acute respiratory distress syndrome (ARDS). By increasing the pulmonary vasodilator response to inhaled nitric oxide and preventing the rebound pulmonary vasoconstriction which occurs following cessation of nitric oxide breathing, selective type 5 isoform of phosphodiesterase inhibitors could be useful in critically ill patients.

SUMMARY

This article reviews recent and key findings on the management of pulmonary hypertension in critically ill patients.

Control strategy on hypertension in chinese medicine

Hypertension is a clinical common disease, with high mortality and disability. Although there have also been significant advances in therapeutic concepts and measures, it has shown a certain value and significance in the treatment of Chinese medicine. The control strategy on hypertension is described from the following aspects such as differentiation of symptoms, pathogenesis, formula syndrome, and herb syndrome. As the common clinical manifestations of hypertension are dizziness, headache, fatigue, lassitude in the loins and knees, and so on, the pathogeneses of them are analysed. The author found that the main pathogenesis of the disease is heat, excessive fluid, and deficiency, which occurred incorporatively and interacted with each other in patients. Although the pathogenesis of the disease is complicated, the distribution of formula syndromes and herb syndromes is regular. The common formula syndromes include Banxia Baishu Tianma Tang (Decoction of Pinellia ternata, Atractylodes and Gastrodia elata), Da Chaihu Tang (Major Bupleurum Decoction), and Liu Wei Dihuang Wan (Pill of Rehmannia). And the common herb syndromes include Tian Ma (Gastrodia elata) syndrome, Sheng Di Huang (Radix Rehmanniae) syndrome, Niu Xi (Achyranthes Root) syndrome, and Chuan Xiong (Ligusticum wallichii) syndrome.

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

Pulmonary arterial hypertension (PAH) is a progressive disease without a cure. The primary treatment goal for patients with this disease is improving pulmonary blood flow through vasodilation of the pulmonary arteries. Several drugs are available that ameliorate walk distance and hemodynamics, but their maximum tolerated doses are limited in critically ill patients with PAH because of systemic vasodilation resulting in hypotension. The ideal vasodilator would be cost-effective, safe, and selective to the pulmonary vasculature; no such agent currently exists. Inhaled nitric oxide selectively reduces pulmonary pressures without systemic hypotension. However, it is expensive, potentially toxic, and requires complex technology for monitoring and administration. Inhaled epoprostenol may be an alternative therapy to minimize systemic hypotension, which often accompanies rapid intravenous titration. To evaluate the safety and efficacy of inhaled epoprostenol in critically ill patients with PAH, we conducted a literature search by using the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases (1966-August 2009) for relevant studies. Case reports and in vitro studies were excluded. Overall, 11 studies met the inclusion criteria. The PAH population included patients requiring cardiac surgery, lung or heart transplantation, or nonspecific intensive care. All trials showed that inhaled epoprostenol significantly decreased pulmonary pressures without lowering systemic blood pressure. The duration of therapy in most studies was 10-15 minutes, with one study evaluating its effects up to an average of 45.6 hours. Pulmonary pressures returned to baseline soon after drug discontinuation. Minimal adverse events were reported. Thus, inhaled epoprostenol in various subgroups of critically ill patients was effective in reducing pulmonary pressures. However, the significance of these effects on improving clinical outcomes remains unknown. Further studies are needed to determine the role of inhaled epoprostenol in critically ill patients with PAH.

Left atrial volume and N-terminal pro-B type natriuretic peptide are associated with elevated pulmonary artery pressure in patients with systemic sclerosis

Early detection of pulmonary hypertension (PH) in patients with systemic sclerosis (SSc) is essential as it leads to substantial morbidity and mortality irrespective of its etiology. The aim of our study was to determine whether noninvasive biochemical and/or echocardiographic indices can predict the presence of PH in these patients. We prospectively studied 66 patients (mean age of 57.7 +/- 12.1 years, 63 women) with SSc without clinical manifestations of heart failure. All patients underwent standard and tissue Doppler echocardiography. Plasma N-terminal pro-B type natriuretic peptide (NT-proBNP) and asymmetric dimethylarginine (ADMA) levels were also measured. In 24 (36%) patients, the diagnosis of PH was established by echocardiography (systolic pulmonary artery pressure value > or =40 mmHg). Left atrial (LA) volume, NT-proBNP, ADMA, ratio of early transmitral filling velocity to early diastolic velocity of the mitral annulus (mitral E/E (m)), and right ventricular myocardial performance index (MPI) were univariate predictors of PH. In multivariate analysis, NT-proBNP, LA volume, and right ventricular MPI were independent predictors of PH in SSc patients. LA volume and NT-proBNP may be useful noninvasive markers for the prediction of elevated pulmonary artery pressure in patients with SSc. These parameters should be considered when assessing this population for risk stratification and for identification of patients demanding further investigation and institution of specific therapy for the disease at the time when it is most likely to be effective.