Successful weaning from cardiopulmonary bypass with central venous prostaglandin E1 and left atrial norepinephrine infusion in patients with acute pulmonary hypertension

Definitions of low cardiac output syndrome after cardiac surgery and their effect on the incidence of intraoperative LCOS: A literature review and cohort study

Objectives

Low cardiac output syndrome (LCOS) is a serious complication after cardiac surgery. Despite scientific interest in LCOS, there is no uniform definition used in current research and clinicians cannot properly compare different study findings. We aimed to collect the LCOS definitions used in literature and subsequently applied the definitions obtained to existing data to estimate their effect on the intraoperative LCOS incidences in adults, children and infants.

Design

This is a literature review, followed by a retrospective cohort study.

Setting

This is a single-institutional study from a university hospital in the Netherlands.

Participants

Patients from all ages undergoing cardiac surgery with cardiopulmonary bypass between June 2011 and August 2018.

Interventions

We obtained different definitions of LCOS used in the literature and applied these to data obtained from an anesthesia information management system to estimate intraoperative incidences of LCOS. We compared intraoperative incidences of LCOS in different populations based on age (infants, children and adults).

Measurements and main results

The literature search identified 262 LCOS definitions, that were applied to intraoperative data from 7,366 patients. Using the 10 most frequently published LCOS definitions, the obtained incidence estimates ranged from 0.4 to 82% in infants, from 0.6 to 56% in children and from 1.5 to 91% in adults.

Conclusion

There is an important variety in definitions used to describe LCOS. When applied to data obtained from clinical care, these different definitions resulted in large distribution of intraoperative LCOS incidence rates. We therefore advocate for standardization of the LCOS definition to improve clinical understanding and enable adequate comparison of outcomes and treatment effects both in daily care and in research.

Opposing responses of the rat pulmonary artery and vein to phenylephrine and other agents in vitro

Background

Different from current cognition, our study demonstrated that adrenergic receptors agonist phenylephrine significantly relaxed isolated pulmonary artery but constricted pulmonary veins. Through comparing differences in the effects of commonly used vasoactive drugs on pulmonary artery and veins, the study aimed to improve efficiency and accuracy of isolated pulmonary vascular experiments, and to provide experimental basis for clinical drug use.

Methods

The contractile responses of pulmonary arteries and veins from twelve-week-old Male Sprague-Dawley rats to phenylephrine, arginine vasopressin (AVP), U46619, endothelin-1, and potassium chloride (KCl) were recorded, as well as the relaxation in response to phenylephrine, AVP, acetylcholine. To further explore the mechanism, some vessels was also pre-incubated with adrenergic receptors antagonists propranolol, prazosin and nitric oxide synthesis inhibitor N[gamma]-nitro-L-arginine methyl ester (L-NAME) before addition of the experimental drugs.

Results

Phenylephrine constricted pulmonary veins directly, but constricted pulmonary artery only after incubation with propranolol or/and L-NAME. The pulmonary artery exhibited significant relaxation to AVP with or without L-NAME incubation. AVP more clearly constricted the veins after incubation with L-NAME. Changes in vascular tension also varied from pulmonary artery to veins for KCl stimulation. Different from phenomena presented in veins, acetylcholine did not relax pulmonary artery preconstricted by KCl, U46619, and endothelin-1.

Conclusions

According to the results, phenylephrine, KCl, AVP, and acetylcholine could be used to distinguish pulmonary arteries and pulmonary veins in vitro. This also suggested that the pulmonary arteries and pulmonary veins have great differences in physiology and drug reactivity.

Inotropic agents and vasodilator strategies for the treatment of cardiogenic shock or low cardiac output syndrome

BACKGROUND

Cardiogenic shock (CS) and low cardiac output syndrome (LCOS) as complications of acute myocardial infarction (AMI), heart failure (HF) or cardiac surgery are life-threatening conditions. While there is a broad body of evidence for the treatment of people with acute coronary syndrome under stable haemodynamic conditions, the treatment strategies for people who become haemodynamically unstable or develop CS remain less clear. We have therefore summarised here the evidence on the treatment of people with CS or LCOS with different inotropic agents and vasodilative drugs. This is the first update of a Cochrane review originally published in 2014.

OBJECTIVES

To assess efficacy and safety of cardiac care with positive inotropic agents and vasodilator strategies in people with CS or LCOS due to AMI, HF or cardiac surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and CPCI-S Web of Science in June 2017. We also searched four registers of ongoing trials and scanned reference lists and contacted experts in the field to obtain further information. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials in people with myocardial infarction, heart failure or cardiac surgery complicated by cardiogenic shock or LCOS.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We identified 13 eligible studies with 2001 participants (mean or median age range 58 to 73 years) and two ongoing studies. We categorised studies into eight comparisons, all against cardiac care and additional other active drugs or placebo. These comparisons investigated the efficacy of levosimendan versus dobutamine, enoximone or placebo, epinephrine versus norepinephrine-dobutamine, amrinone versus dobutamine, dopexamine versus dopamine, enoximone versus dopamine and nitric oxide versus placebo.All trials were published in peer-reviewed journals, and analysis was done by the intention-to-treat (ITT) principle. Twelve of 13 trials were small with few included participants. Acknowledgement of funding by the pharmaceutical industry or missing conflict of interest statements emerged in five of 13 trials. In general, confidence in the results of analysed studies was reduced due to serious study limitations, very serious imprecision or indirectness. Domains of concern, which show a high risk of more than 50%, include performance bias (blinding of participants and personnel) and bias affecting the quality of evidence on adverse events.Levosimendan may reduce short-term mortality compared to a therapy with dobutamine (RR 0.60, 95% CI 0.37 to 0.95; 6 studies; 1776 participants; low-quality evidence; NNT: 16 (patients with moderate risk), NNT: 5 (patients with CS)). This initial short-term survival benefit with levosimendan vs. dobutamine is not confirmed on long-term follow up. There is uncertainty (due to lack of statistical power) as to the effect of levosimendan compared to therapy with placebo (RR 0.48, 95% CI 0.12 to 1.94; 2 studies; 55 participants, very low-quality evidence) or enoximone (RR 0.50, 95% CI 0.22 to 1.14; 1 study; 32 participants, very low-quality evidence).All comparisons comparing other positive inotropic, inodilative or vasodilative drugs presented uncertainty on their effect on short-term mortality with very low-quality evidence and based on only one RCT. These single studies compared epinephrine with norepinephrine-dobutamine (RR 1.25, 95% CI 0.41 to 3.77; 30 participants), amrinone with dobutamine (RR 0.33, 95% CI 0.04 to 2.85; 30 participants), dopexamine with dopamine (no in-hospital deaths from 70 participants), enoximone with dobutamine (two deaths from 40 participants) and nitric oxide with placebo (one death from three participants).

AUTHORS' CONCLUSIONS

Apart from low quality of evidence data suggesting a short-term mortality benefit of levosimendan compared with dobutamine, at present there are no robust and convincing data to support a distinct inotropic or vasodilator drug-based therapy as a superior solution to reduce mortality in haemodynamically unstable people with cardiogenic shock or LCOS.Considering the limited evidence derived from the present data due to a generally high risk of bias and imprecision, it should be emphasised that there remains a great need for large, well-designed randomised trials on this topic to close the gap between daily practice in critical care medicine and the available evidence. It seems to be useful to apply the concept of 'early goal-directed therapy' in cardiogenic shock and LCOS with early haemodynamic stabilisation within predefined timelines. Future clinical trials should therefore investigate whether such a therapeutic concept would influence survival rates much more than looking for the 'best' drug for haemodynamic support.

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.

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.

Perioperative pharmacological management of pulmonary hypertensive crisis during congenital heart surgery

Pulmonary hypertensive crisis is an important cause of morbidity and mortality in patients with pulmonary arterial hypertension secondary to congenital heart disease (PAH-CHD) who require cardiac surgery. At present, prevention and management of perioperative pulmonary hypertensive crisis is aimed at optimizing cardiopulmonary interactions by targeting prostacyclin, endothelin, and nitric oxide signaling pathways within the pulmonary circulation with various pharmacological agents. This review is aimed at familiarizing the practitioner with the current pharmacological treatment for dealing with perioperative pulmonary hypertensive crisis in PAH-CHD patients. Given the life-threatening complications associated with pulmonary hypertensive crisis, proper perioperative planning can help anticipate cardiopulmonary complications and optimize surgical outcomes in this patient population.

The management of acute pulmonary arterial hypertension

Acute pulmonary arterial hypertension (PAH), which may complicate the course of many complex disorders, is always underdiagnosed and its treatment frequently begins only after serious complications have developed. Acute PAH is distinctive because they differ in their clinical presentation, diagnostic findings, and response to treatment from chronic PAH. The acute PAH may take either the form of acute onset of chronic PAH or acute PAH or surgery-related PAH. Significant pathophysiologic differences existed between acute and chronic PAH. Therapy of acute PAH should generally be aimed at acutely relieving right ventricular (RV) pressure overload and preventing RV dysfunction. There are three classes of drugs targeting the correction of abnormalities in endothelial dysfunction, which have been approved recently for the treatment of PAH: (1) prostanoids; (2) endothelin receptor antagonists; and (3) phosphodiesterase-5 inhibitors. The efficacy and safety of these compounds have been confirmed in uncontrolled studies in patients with PAH. Intravenous epoprostenol is suggested to serve as the first-line treatment for the most severe patients. In the other situations, the first-line therapy may include bosentan, sildenafil, or a prostacyclin analogue. Recent advances in the management of PAH have markedly improved prognosis.

Arterial pulmonary hypertension in noncardiac intensive care unit

Pulmonary artery pressure elevation complicates the course of many complex disorders treated in a noncardiac intensive care unit. Acute pulmonary hypertension, however, remains underdiagnosed and its treatment frequently begins only after serious complications have developed. Significant pathophysiologic differences between acute and chronic pulmonary hypertension make current classification and treatment recommendations for chronic pulmonary hypertension barely applicable to acute pulmonary hypertension. In order to clarify the terminology of acute pulmonary hypertension and distinguish it from chronic pulmonary hypertension, we provide a classification of acute pulmonary hypertension according to underlying pathophysiologic mechanisms, clinical features, natural history, and response to treatment. Based on available data, therapy of acute arterial pulmonary hypertension should generally be aimed at acutely relieving right ventricular (RV) pressure overload and preventing RV dysfunction. Cases of severe acute pulmonary hypertension complicated by RV failure and systemic arterial hypotension are real clinical challenges requiring tight hemodynamic monitoring and aggressive treatment including combinations of pulmonary vasodilators, inotropic agents and systemic arterial vasoconstrictors. The choice of vasopressor and inotropes in patients with acute pulmonary hypertension should take into consideration their effects on vascular resistance and cardiac output when used alone or in combinations with other agents, and must be individualized based on patient response.

Pulmonary circulatory effects of norepinephrine in newborn infants with persistent pulmonary hypertension

OBJECTIVE

To evaluate the respiratory and the pulmonary circulatory effects of norepinephrine in newborn infants with persistent pulmonary hypertension (PPHN)-induced cardiac dysfunction.

STUDY DESIGN

Inclusion criteria were: 1) Newborn infants >35 weeks gestational age; 2) PPHN treated with inhaled nitric oxide; and 3) symptoms of circulatory failure despite adequate fluid resuscitation. Lung function and pulmonary hemodynamic variables assessed with Doppler echocardiography were recorded prospectively before and after starting norepinephrine.

RESULTS

Eighteen newborns were included (gestational age: 37 +/- 3 weeks; birth weight: 2800 +/- 700 g). After starting norepinephrine, systemic pressure and left ventricular output increased respectively from 33 +/- 4 mm Hg to 49 +/- 4 mm Hg and from 172 +/- 79 mL/kg/min to 209+/-90 mL/kg/min (P < .05). Although the mechanical ventilatory variables have not been changed, the post-ductal transcutaneous arterial oxygen saturation increased from 89% +/- 1% to 95% +/- 4%, whereas the oxygen need decreased from 51% +/- 24% to 41% +/- 20% (P < .05). The pulmonary/systemic pressure ratio decreased from 0.98 +/- 0.1 to 0.87 +/- 0.1 (P < .05). Mean left pulmonary artery blood flow velocity increased by 20% (P < .05).

CONCLUSION

Norepinephrine may improve lung function in newborn infants with PPHN through a decrease in pulmonary/systemic artery pressure ratio and improved cardiac performance.

Noradrenaline for management of septic shock refractory to fluid loading and dopamine or dobutamine in full-term newborn infants

AIM

To determine the effects of noradrenaline in full-term newborns with refractory septic shock.

METHODS

Newborns of >35 weeks' gestation with persistent septic shock, despite adequate fluid resuscitation and high dose of dopamine/dobutamine were eligible. In this prospective observational study, we recorded respiratory and hemodynamic parameters prior to and 3 h after starting noradrenaline infusion.

RESULTS

Twenty-two newborns were included (gestational age [GA] 39 +/- 1.7 weeks, birth weight (BW) 3110 +/- 780 g). Before starting noradrenaline, the infants received a mean volume expansion of 31 +/- 15 mL/kg and a mean infusion rate of dopamine of 14 +/- 5 microg/kg/min or dobutamine of 12 +/- 6 microg/kg/min. Three hours after starting noradrenaline (rate 0.5 +/- 0.4 microg/kg/min), the mean arterial blood pressure rose from 36 +/- 5 to 51 +/- 7 mmHg (p < 0.001). Urine output increased from 1 +/- 0.5 to 1.7 +/- 0.4 mL/kg/h (p < 0.05). Blood lactate concentration decreased from 4.8 +/- 2.3 to 3.3 +/- 1.8 mmol/L (p < 0.01). Despite an initial correction of hypotension, four infants died later.

CONCLUSION

Noradrenaline was effective in increasing systemic blood pressure. An increase in urine output and a decrease in blood lactate concentration suggest that noradrenaline may have improved cardiac function and tissue perfusion.

Management strategies for patients with pulmonary hypertension in the intensive care unit

OBJECTIVE

Pulmonary hypertension may be encountered in the intensive care unit in patients with critical illnesses such as acute respiratory distress syndrome, left ventricular dysfunction, and pulmonary embolism, as well as after cardiothoracic surgery. Pulmonary hypertension also may be encountered in patients with preexisting pulmonary vascular, lung, liver, or cardiac diseases. The intensive care unit management of patients can prove extremely challenging, particularly when they become hemodynamically unstable. The objective of this review is to discuss the pathogenesis and physiology of pulmonary hypertension and the utility of various diagnostic tools, and to provide recommendations regarding the use of vasopressors and pulmonary vasodilators in intensive care.

DATA SOURCES AND EXTRACTION

We undertook a comprehensive review of the literature regarding the management of pulmonary hypertension in the setting of critical illness. We performed a MEDLINE search of articles published from January 1970 to March 2007. Medical subject headings and keywords searched and cross-referenced with each other were: pulmonary hypertension, vasopressor agents, therapeutics, critical illness, intensive care, right ventricular failure, mitral stenosis, prostacyclin, nitric oxide, sildenafil, dopamine, dobutamine, phenylephrine, isoproterenol, and vasopressin. Both human and animal studies related to pulmonary hypertension were reviewed.

CONCLUSIONS

Pulmonary hypertension presents a particular challenge in critically ill patients, because typical therapies such as volume resuscitation and mechanical ventilation may worsen hemodynamics in patients with pulmonary hypertension and right ventricular failure. Patients with decompensated pulmonary hypertension, including those with pulmonary hypertension associated with cardiothoracic surgery, require therapy for right ventricular failure. Very few human studies have addressed the use of vasopressors and pulmonary vasodilators in these patients, but the use of dobutamine, milrinone, inhaled nitric oxide, and intravenous prostacyclin have the greatest support in the literature. Treatment of pulmonary hypertension resulting from critical illness or chronic lung diseases should address the primary cause of hemodynamic deterioration, and pulmonary vasodilators usually are not necessary.

Selecting a Vasopressor Drug for Vasoplegic Shock After Adult Cardiac Surgery: A Systematic Literature Review

The choice of vasopressors to treat vasodilatory shock after cardiac surgery is a matter of controversy. We have systematically reviewed the literature and found that the data are insufficient to guide choice of agent. However, we found sufficient evidence that when a target blood pressure can not be achieved with a single agent, addition of another is more likely to help achieve the blood pressure target. We also found that there is no evidence that vasopressors induce organ ischemia. Finally, the lack of high quality data indicate that large multicenter trials are needed in this field.

New approaches for persistent pulmonary hypertension of newborn

The management of PPHN entered a new era with the development of inhaled NO therapy for the relief of pulmonary hypertension. The wider application of INO therapy and improved ventilation strategies led to a decrease in the need for invasive life-sustaining therapies such as ECMO. The remarkable advances in the understanding and treatment of PPHN were made possible by the extensive investigations in the laboratory using animal models. Further decreases in morbidity and mortality are possible with specific strategies targeted to correct the alterations in NO and prostacyclin biology and strategies to reduce lung injury. Further research is needed to understand the basis for the biologic susceptibility of some infants to environmental insults such as intra-uterine stressor exposure to NSAIDs in utero.