Arginine vasopressin to manage hypoxemic infants after stage I palliation of single ventricle lesions

Hemodynamic Management with Vasopressin for Cardiovascular Surgery

Background and Objectives: Vasopressin increases blood pressure through aquaporin-2-mediated water retention and is useful for managing hemodynamics after surgery. However, even after decades of study, clear clinical guidelines on doses and ideal use cases after cardiovascular surgery remain unclear. Here, the existing literature is synthesized on vasopressin use for cardiac surgeries and coupled with real-world clinical experience to outline a clearer clinical path for vasopressin use. Materials and Methods: Literature from 1966 to the present was searched, and information on surgical outcomes for cardiovascular surgery was extracted. Clinicians from the University of Tsukuba with extensive vasopressin experience in pediatric cardiovascular patients were consulted for general use guidelines. Results: Vasopressin response after cardiovascular surgery is multifaceted, and low-power trials, plus conflicting study reports, generally render it as a secondary choice behind norepinephrine. Clinical experience indicates that low doses of 0.2-0.3 mU/kg/min with constant blood pressure and oxygen monitoring for response are required. Although sole use is not recommended, vasopressin may aid in controlling hemodynamics when given with other volemic or osmolal drugs. Conclusions: Vasopressin may work in a select population of first-line non-responders, but relevant response factors remain unanalyzed and clear guidelines for use remain unestablished. Future, large-scale studies are needed to delineate temporal and demographic characteristics that affect response to vasopressin for the purpose of managing post-surgical capillary leakage and hemodynamics.

Vasopressin associated hyponatremia in critically ill children: A cross-sectional study

Background

The association of hyponatremia with vasopressin therapy in children is controversial. We aimed to evaluate the incidence and severity of hyponatremia associated with the administration of vasopressin in critically ill pediatric patients.

Methods

This retrospective cross-sectional study included children younger than 14 years who were admitted to the pediatric or pediatric cardiac intensive care units and received vasopressin for at least 24 h.

Results

In total, 176 critically ill pediatric patients were enrolled, with a median age of 22 days (7.3–146). The mean sodium level was notably decreased from 143.5 mEq/L ± 7.15 at the baseline to 134.3 mEq/L ± 7.7 at the 72-hour measurement after the initiation of vasopressin and varied significantly at all intervals from the baseline measurement (P < 0.001). Twenty-four hours after the discontinuation of vasopressin, more than half of the patients had hyponatremia. The highest proportion had mild hyponatremia (32.8%), followed by moderate hyponatremia (13.1%), and profound hyponatremia (7.5%). The incidence of hyponatremia was independent of gender (P = 0.94) or age group (P = 0.087). However, more than two-thirds of the moderate-profound cases and more than one-third of mild cases were observed in the neonate group (P = 0.043). The vasopressin dose did not affect the incidence (P = 0.25) or the severity of the hyponatremia (P = 0.56). Notably, all laboratory and hemodynamic parameters varied significantly at the end of therapy, compared to the baseline.

Conclusions

Continuous monitoring for hyponatremia when children are placed on vasopressin is essential to protect against more severe complications.

Impact of Medical Interventions and Comorbidities on Norwood Admission for Patients with Hypoplastic Left Heart Syndrome

The purpose of these analyses was to determine how specific comorbidities and medical interventions impact risk of inpatient mortality in those with hypoplastic left heart syndrome undergoing Norwood procedure. The secondary aims were to determine the impact of these on billed charges, postoperative length of stay, and risk of cardiac arrest. Admissions from 2004 to 2015 in the Pediatric Health Information System database with hypoplastic left heart syndrome and Norwood procedure were identified. Admission characteristics, patient interventions, and the presence of comorbidities were captured. A total of 5,138 admissions were identified meeting inclusion criteria. Of these 829 (16.1%) experienced inpatient mortality, and 352 (6.7%) experienced cardiac arrest. The frequency of inpatient mortality did not significantly change over the course of the study era. The frequency of cardiac arrest significantly decreased from 7.4% in 2004 to 4.3% in 2015 (p = 0.04). The frequency of pharmacologic therapies, particularly vasoactive use, decreased as the study period progressed. Regression analyses demonstrated a significant association between cardiac arrest and inpatient mortality with arrhythmias, acute kidney injury, and pulmonary hypertension. Similarly, regression analyses demonstrated a significant association between increase in billed charges and length of stay with year of surgery, presence of heart failure, syndromes, and acute kidney injury. For patients with hypoplastic left heart syndrome undergoing the Norwood procedure, the frequency of pharmacologic therapies and cardiac arrest has decreased over time. There are significant associations between acute kidney injury, arrythmias, and pulmonary hypertension with cardiac arrest and mortality.

Acute Effects of Vasopressin Arginine Infusion in Children with Congenital Heart Disease: Higher Blood Pressure Does Not Equal Improved Systemic Oxygen Delivery

The use of vasopressin has been increased in recent years in children after congenital heart surgery. However, there is limited information regarding its effects on cardiac output, systemic oxygen delivery, and myocardial energetics. The purpose of this study is to characterize the effects of vasopressin infusions on hemodynamics and systemic oxygen delivery in children with congenital heart disease. A retrospective, single-center study of patients with congenital heart disease who received vasopressin infusions in a pediatric cardiac intensive care unit between January 2019 and May 2020. The measured values collected for study were systolic and diastolic blood pressure, heart rate, arterial oxygen saturation as determined by pulse oximetry, arterial pH, arterial partial pressure of oxygen, arterial partial pressure of carbon dioxide, serum lactate, serum sodium, and renal and cerebral oximetry based on near-infrared spectroscopy. The calculated values for this study were the difference between arterial and NIRS oximetry, the reno-cerebral near-infrared spectroscopy gradient and the vasoinotrope score. A Wilcoxon signed-rank test was utilized to compare values of paired continuous variables before and after initiation of the vasopressin infusion. Correlations were assessed using Spearman correlation analyses and stepwise regressions were completed. A total of 26 vasopressin infusions among 20 unique patients were included in the final analyses. Of these 26 vasopressin infusions, 18 were in patients with biventricular circulation and 8 were in patients with functionally univentricular circulation. The median vasopressin infusion dose at initiation was 0.4 (0.1-1) milliunits/kg/min. For the entire cohort 2 h after the initiation of vasopressin, systolic blood pressure increased to 8.4 mmHg, p < 0.01, but no significant correlation was found to markers of systemic oxygen delivery. Similar results were obtained when only those with biventricular circulation were considered. Those with functionally univentricular circulation were not found to have any statistically significant rise in blood pressure. Vasopressin infusions appear to statistically significantly increase systolic blood pressure in children with congenital heart disease who have a biventricular but not functionally univentricular circulation. Even when an increase in systolic blood pressure is present, systemic oxygen delivery did not improve.

International Survey on the Use of Arginine Vasopressin in the Postoperative Management of Single Ventricle Patients

Management of patients with single ventricle physiology after surgical palliation is challenging. Arginine vasopressin has gained popularity in recent years as a non-catecholamine vasoactive medication due to its unique properties. However, data regarding its use in the pediatric population is limited. Therefore, we designed a survey to explore whether and how clinicians use this medication in intensive care units for the postoperative management of single ventricle patients. This international survey aimed to assess usage, practices, and concepts related to arginine vasopressin in pediatric intensive care units worldwide. Directors of pediatric intensive care units who are members of the following international professional societies: European Society of Pediatric Neonatal Intensive Care, Association for European Pediatric and Congenital Cardiology, and Pediatric Cardiac Intensive Care Society were invited to participate in this survey. Of the 62 intensive care unit directors who responded, nearly half use arginine vasopressin in the postoperative management of neonatal single ventricle patients, and 90% also use the drug in subsequent surgical palliation. The primary indications are vasoplegia, hemodynamic instability, and refractory shock, although it is still considered a second-line medication. Conceptual benefits include improved hemodynamics and end-organ perfusion and decreased incidence of low cardiac output syndrome. Those practitioners who do not use arginine vasopressin cite lack of availability, fear of potential adverse effects, unclear indication for use, and lack of evidence suggesting improved outcomes. Both users and non-users described increased myocardial afterload and extreme vasoconstriction as potential disadvantages of the medication. Despite the lack of conclusive data demonstrating enhanced clinical outcomes, our study found arginine vasopressin is used widely in the care of infants and children with single ventricle physiology after the first stage and subsequent palliative surgeries. While many intensive care units use this medication, few had protocols, offering an area for further growth and development.

Effects of Vasopressin Infusion After Pediatric Cardiac Surgery: A Meta-analysis

Vasopressin has been used to augment blood pressure; however, cardiovascular effects after cardiac surgery have not been well established. The primary objective of this study was to survey the current literature and quantify the pooled effect of vasopressin on hemodynamic parameters in children after pediatric cardiac surgery. A systematic review was conducted to identify studies characterizing the hemodynamic effects of vasopressin after pediatric cardiac surgery. Studies were assessed and those of satisfactory quality with pre- and post-vasopressin hemodynamics for each patient were included in the final analyses. 6 studies with 160 patients were included for endpoints during the first 2 h of infusions. Patients who received vasopressin infusion had greater mean, systolic, and diastolic blood pressures and lower heart rates at 2 h after initiation. 8 studies with 338 patients were included for the effects at 24 h. Patients who received vasopressin infusion had lower central venous pressures and decreased lactate concentrations 24 h after initiation. A subset analysis for children with functionally univentricular hearts found significant decrease in inotrope score and central venous pressure. A subset analysis for neonates found significant decrease in inotrope score and fluid balance. Vasopressin leads to decrease in heart rate and increase in blood pressure in the first 2 h of initiation. Later effects include decrease in inotrope score, central venous pressure, fluid balance, and in lactate within the first 24 h. Findings vary in neonates and in those with functionally univentricular hearts although beneficial effects are noted in both.

The role of oxytocin and vasopressin in the pathophysiology of heart failure in pregnancy and in fetal and neonatal life

Pregnancy and early life create specific psychosomatic challenges for the mother and child, such as changes in hemodynamics, resetting of the water-electrolyte balance, hypoxia, pain, and stress, that all play an important role in the regulation of the release of oxytocin and vasopressin. Both of these hormones regulate the water-electrolyte balance and cardiovascular functions, maturation of the cardiovascular system, and cardiovascular responses to stress. These aspects may be of particular importance in a state of emergency, such as hypertension in the mother or severe heart failure in the child. In this review, we draw attention to a broad spectrum of actions exerted by oxytocin and vasopressin in the pregnant mother and the offspring during early life. To this end, we discuss the following topics: 1) regulation of the secretion of oxytocin and vasopressin and expression of their receptors in the pregnant mother and child, 2) direct and indirect effects of oxytocin and vasopressin on the cardiovascular system in the healthy mother and fetus, and 3) positive and negative consequences of altered secretion of oxytocin and vasopressin in the mother with cardiovascular pathology and in the progeny with heart failure. The present survey provides evidence that moderate stimulation of the oxytocin and vasopressin receptors plays a beneficial role in the healthy pregnant mother and fetus; however, under pathophysiological conditions the inappropriate action of these hormones exerts several negative effects on the cardiovascular system of the mother and progeny and may potentially contribute to the pathophysiology of heart failure in early life.

Experts' recommendations for the management of cardiogenic shock in children

Cardiogenic shock which corresponds to an acute state of circulatory failure due to impairment of myocardial contractility is a very rare disease in children, even more than in adults. To date, no international recommendations regarding its management in critically ill children are available. An experts’ recommendations in adult population have recently been made (Levy et al. Ann Intensive Care 5(1):52, 2015; Levy et al. Ann Intensive Care 5(1):26, 2015). We present herein recommendations for the management of cardiogenic shock in children, developed with the grading of recommendations’ assessment, development, and evaluation system by an expert group of the Groupe Francophone de Réanimation et Urgences Pédiatriques (French Group for Pediatric Intensive Care and Emergencies). The recommendations cover four major fields of application such as: recognition of early signs of shock and the patient pathway, management principles and therapeutic goals, monitoring hemodynamic and biological variables, and circulatory support (indications, techniques, organization, and transfer criteria). Major principle care for children with cardiogenic shock is primarily based on clinical and echocardiographic assessment. There are few drugs reported as effective in childhood in the medical literature. The use of circulatory support should be facilitated in terms of organization and reflected in the centers that support these children. Children with cardiogenic shock are vulnerable and should be followed regularly by intensivist cardiologists and pediatricians. The experts emphasize the multidisciplinary nature of management of children with cardiogenic shock and the importance of effective communication between emergency medical assistance teams (SAMU), mobile pediatric emergency units (SMUR), pediatric emergency departments, pediatric cardiology and cardiac surgery departments, and pediatric intensive care units.

Duration and magnitude of vasopressor support predicts poor outcome after infant cardiac operations

BACKGROUND

The vasoactive inotrope score (VIS) is a sum of the total vasopressor dose at a single point in time. Incorporating duration and magnitude of vasopressor requirements during the postcardiac surgical period could improve VIS sensitivity for predicting poor outcome.

METHODS

This is a retrospective review of 244 infants (aged ≤365 days) who underwent cardiopulmonary bypass during congenital cardiac operations from 2002 to 2011. The VIS was calculated hourly for the first 72 hours. Poor outcome was defined as prolonged mechanical ventilation (≥6 days) or intensive care length of stay (≥12 days). First, the association between the maximum VIS (maxVIS) in the first 48 postoperative hours and poor outcome was confirmed for our study population. Next, postoperative intervals and VIS values that were significantly associated with poor outcome were identified and incorporated into a formula, termed the VISindex, which was compared with the traditional maxVIS.

RESULTS

The VISindex demonstrated improved sensitivity for predicting prolonged mechanical ventilation (VISindex: area under the curve [AUC], 0.85; 95% confidence interval [CI], 0.79 to 0.90; maxVIS: AUC, 0.80; 95% CI, 0.75 to 0.86) and intensive care unit length of stay (VISindex: AUC, 0.84; 95% CI, 0.79 to 0.89; maxVIS: AUC, 0.77; 95% CI, 0.71 to 0.83) after cardiac operations in infants.

CONCLUSIONS

Incorporating magnitude and duration of postoperative vasopressor support into the VIS improves its sensitivity for predicting poor outcome.

Vasoactive-inotropic score after pediatric heart transplant: a marker of adverse outcome

VIS, a quantitative index of pressor support, has been shown to be a predictor of morbidity and mortality in infants younger than six months who underwent CPB. Data on its prognostic utility following pediatric OHT are lacking. This study compared clinical outcomes in children with differential VIS after pediatric OHT. A retrospective cohort study of 51 consecutive heart transplants from 2004 to 2011 was performed at a pediatric tertiary care facility. Peak VIS was computed within initial 24 and 48 h after OHT and was weighted for peak dose and administration of any or all of six pressors. Patients with peak VIS ≥ 15 constituted high VIS group. Children who persistently required a higher magnitude of pressor support for the first 48 h after OHT, as reflected by high peak VIS, had significantly longer ICU stay (30.2 vs. 15.9 days, p = 0.01), pressor (11.4 vs. 6.8 days, p = 0.02) and ventilatory durations (12.4 vs. 5.9 days, p = 0.05), and higher rates of short-term morbidities. Patients with longer CPB (213 vs. 153 min, p = 0.005) time have higher peak VIS. High peak VIS at 48 h is an effective, yet simple clinical marker for adverse outcomes in pediatric OHT recipients.

Clinical response to arginine vasopressin therapy after paediatric cardiac surgery

OBJECTIVE

To describe the haemodynamic response of children who receive arginine vasopressin for haemodynamic instability after cardiac surgery and to identify clinical variables associated with a favourable response. Materials and Methods We reviewed patients less than or equal to 6 years undergoing open heart surgery in our institution between January, 2009 and July, 2010 who received arginine vasopressin during the first 7 days post operation. Favourable responders were defined as those in whom blood pressure was increased or maintained and catecholamine score was decreased, or blood pressure was increased by greater than or equal to 10% of baseline and catecholamine score was unchanged at 6 hours following arginine vasopressin initiation.

RESULTS

Of the 34 patients identified, 17 (50%) patients responded favourably to arginine vasopressin. At 6 hours, the mean blood pressure was increased by 32.2% in responders as compared with 4.6% in non-responders, with a p-value less than 0.001. The mean catecholamine score decreased by 30.1% in responders and increased by 7.6% in non-responders, with a p-value less than 0.001. Anthropometric, demographic, and intra-operative variables were similar in both groups, as was maximum dose of arginine vasopressin. The median time after arrival to the intensive care unit at which arginine vasopressin was initiated, however, was later in those who responded, 20 hours as compared with those who did not, 6 hours, with a p-value equal to 0.032.

CONCLUSIONS

Arginine vasopressin therapy led to haemodynamic improvement in only half of the children in this study, and improvement was more likely to occur if arginine vasopressin was initiated after the post-operative night.

Vasopressin and its analogues for the treatment of refractory hypotension in neonates

BACKGROUND

Neonatal hypotension that is refractory to volume expansion, catecholamines, or corticosteroids has a mortality of about 50%. Optimization of blood pressure and tissue perfusion in refractory hypotension may be crucial to improve clinical outcomes. Vasopressin, a neuropeptide hormone, or its analogue terlipressin has been used to treat refractory hypotension in neonates and may be effective.

OBJECTIVES

Our primary objective was to evaluate the efficacy and safety of vasopressin and its synthetic analogues (e.g. terlipressin) in decreasing mortality and adverse neurodevelopmental outcomes, and improving survival in neonates with refractory hypotension. Our secondary objectives were to determine the effects of vasopressin and its analogues (terlipressin) on improvement in blood pressure, increase in urine output, decrease in inotrope score, necrotizing enterocolitis (NEC), periventricular leukomalacia, intraventricular hemorrhage, chronic lung disease, and retinopathy of prematurity (ROP) in neonates with refractory hypotension.

SEARCH METHODS

We searched the literature in January 2012, using the search strategy recommended by the Cochrane Neonatal Group. We searched electronic databases (CENTRAL (The Cochrane Library), MEDLINE, CINAHL, EMBASE), abstracts of the Pediatric Academic Societies, web sites for registered trials at www.clinicaltrials.gov and www.controlled-trials.com and in the reference list of identified articles.

SELECTION CRITERIA

Randomized or quasi-randomized trials evaluating vasopressin or its analogues, at any dosage or duration used as an adjunct to standard therapy (any combination of volume expansion, inotropic agents and corticosteroids) to treat refractory hypotension in neonates.

DATA COLLECTION AND ANALYSIS

We followed the standard methods of The Cochrane Collaboration for conducting a systematic review. Two review authors (BS and MP) independently assessed the titles and abstracts of studies identified by the search strategy for eligibility for inclusion. We obtained the full text version if eligibility could not be done reliably by title and abstract. We resolved any differences by mutual discussion. We designed electronic forms for trial inclusion/exclusion, data extraction, and for requesting additional published information from authors of the original reports.

MAIN RESULTS

Our search did not identify any completed or ongoing trials that met our inclusion criteria. Three studies that did not include neonates and one study where the objective was not to treat neonates with refractory hypotension were excluded.

AUTHORS' CONCLUSIONS

There is insufficient evidence to recommend or refute the use of vasopressin or its analogues in the treatment of refractory hypotension in neonates. Well-designed, adequately powered, randomized controlled studies are necessary to address efficacy, optimal dosing, safety and long-term neurodevelopmental and pulmonary outcomes. 

Hyponatremia during arginine vasopressin therapy in children following cardiac surgery

OBJECTIVE

To describe the incidence and severity of hyponatremia after initiation of arginine vasopressin therapy in children recovering from cardiothoracic surgery, and to compare these patients with a control group with similar disease complexity and severity who did not receive arginine vasopressin.

DESIGN

Retrospective chart review.

SETTING

PICU at a tertiary care university hospital.

PATIENTS

Twenty-nine patients who received arginine vasopressin for at least 6 hours during the first 48 postoperative hours following cardiothoracic surgery were compared with 47 patients who did not receive arginine vasopressin. After surgery, all patients received intravenous fluids consisting of dextrose and 0.22% saline for daily fluid requirements as well as isotonic colloid and blood products as needed for additional resuscitation.

RESULTS

Mean initial postoperative serum sodium did not differ between groups, 144.6 ± 3.4 in those patients who received arginine vasopressin and 144.5 ± 3.7 in those who did not, p = 0.969. Mean lowest sodium in the first 72 hours, however, was 134.7 ± 3.8 in those who received arginine vasopressin as compared with 137.1 ± 4.3 in the control group, p = 0.019. Hyponatremia occurred in 14 of the patients (48%) who received arginine vasopressin but only in 8 of the patients (17%) in the control group, p = 0.004. Mean age, weight, sex, Aristotle score, and duration of cardiopulmonary bypass were not statistically different between groups. Mean volumes of hypotonic fluids administered and cumulative diuretic dosing during the first 72 hours post-surgery were also not statistically different between groups.

CONCLUSIONS

Hyponatremia occurred in nearly half of the infants and children receiving arginine vasopressin therapy in this study. Clinicians should be aware of this association, monitor serum sodium values closely, and consider providing less free water to these patients before hyponatremia occurs.

Prospective validation of the vasoactive-inotropic score and correlation to short-term outcomes in neonates and infants after cardiothoracic surgery

PURPOSE

Prospective validation of the vasoactive-inotropic score (VIS) and inotrope score (IS) in infants after cardiovascular surgery.

METHODS

Prospective observational study of 70 infants (≤90 days of age) undergoing cardiothoracic surgery. VIS and IS were assessed at 24 (VIS24, IS24), 48 (VIS48, IS48), and 72 (VIS72, IS72) h after surgery. Maximum VIS and IS scores in the first 48 h were also calculated (VIS48max and IS48max). The primary outcome was length of intubation. Additional outcomes included length of intensive care (ICU) stay and hospitalization, cardiac arrest, mortality, time to negative fluid balance, peak lactate, and change in creatinine.

RESULTS

Based on receiver-operating characteristic (ROC) analysis, the area under the curve (AUC) was highest for VIS48 to identify prolonged intubation time. AUC for the primary outcome was higher for VIS than IS at all time points assessed. On multivariate analysis VIS48 was independently associated with prolonged intubation (OR 22.3, p = 0.002), prolonged ICU stay (OR 8.1, p = 0.017), and prolonged hospitalization (OR 11.3, p = 0.011). VIS48max, IS48max, and IS48 were also associated with prolonged intubation, but not prolonged ICU or hospital stay. None of the scores were associated with time to negative fluid balance, peak lactate, or change in creatinine.

CONCLUSION

In neonates and infants, a higher VIS at 48 h after cardiothoracic surgery is strongly associated with increased length of ventilation, and prolonged ICU and total hospital stay. At all time points assessed, VIS is more predictive of poor short-term outcome than IS. VIS may be useful as an independent predictor of outcomes.

Early initiation of arginine vasopressin infusion in neonates after complex cardiac surgery

OBJECTIVE

To describe our experience with low-dose arginine vasopressin infusions (0.0003 U/kg/min) initiated in the operating room after the Norwood procedure or arterial switch operation.

DESIGN

Retrospective cohort study of 37 consecutive neonates.

SETTING

Pediatric cardiovascular intensive care unit in a tertiary hospital.

SUBJECTS

Nineteen patients that received low-dose arginine vasopressin infusion instituted in the operating room (arginine vasopressin+) were compared to 18 patients that did not receive early arginine vasopressin infusion (arginine vasopressin-).

INTERVENTIONS

None.

RESULTS

When comparing arginine vasopressin+ and arginine vasopressin- in the first 24 hrs after cardiovascular intensive care unit admission, there was no difference in demographic variables, heart rate, blood pressure, central venous pressure, maximum lactate, maximum arterial and central venous saturation difference, urine output, chest tube output, or peritoneal drain output. Mean fluid resuscitation in the first 24 hrs was significantly lower in the arginine vasopressin+ group compared to the arginine vasopressin- group (182 ± 61 mL/kg vs. 223 ± 53 mL/kg, p = .03). The arginine vasopressin+ group also reached median net negative cumulative fluid balance sooner (55 hrs: interquartile range 45, 74 vs. 76 hrs: interquartile range 69, 92; p = .02). Median maximum inotrope score in the first 24 hrs was significantly lower in arginine vasopressin+ (9: interquartile range 5, 12.5 vs. 16.5: interquartile range 10.3, 22.1; p = .02). There was a nonsignificant trend toward shorter duration of mechanical ventilation and cardiovascular intensive care unit length of stay in the arginine vasopressin+ group. The lowest serum sodium in the first 48 hrs was significantly lower in arginine vasopressin+ (132 vs. 137 mmol/L, p = .01).

CONCLUSION

Low-dose arginine vasopressin infusion initiated in the operating room after complex neonatal cardiac surgery was associated with decreased fluid resuscitation and catecholamine requirements in the first 24 postoperative hours.

Therapeutic applications of vasopressin in pediatric patients

CONTEXT

Reports of successful use of vasopressin in various shock states and cardiac arrest has lead to the emergence of vasopressin therapy as a potentially major advancement in the management of critically ill children.

OBJECTIVE

To provide an overview of physiology of vasopressin, rationale of its use and dose schedule in different disease states with special focus on recent advances in the therapeutic applications of vasopressin.

DATA SOURCE

MEDLINE search (1966-September 2011) using terms vasopressin, terlipressin, arginine-vasopressin, shock, septic shock, vasodilatory shock, cardiac arrest, and resuscitation for reports on vasopressin/terlipressin use in children and manual review of article bibliographies. Search was restricted to human studies. Randomized controlled trials, cohort studies, evaluation studies, case series, and case reports on vasopressin/terlipressin use in children (preterm neonates to 21 years of age) were included. Outcome measures were analysed using following clinical questions: indication, dose and duration of vasopressin/terlipressin use, main effects especially on systemic blood pressure, catecholamine requirement, urine output, serum lactate, adverse effects, and mortality.

RESULTS

51 reports on vasopressin (30 reports) and terlipressin (21 reports) use in pediatric population were identified. A total of 602 patients received vasopressin/terlipressin as vasopressors in various catecholamine-resistant states (septic - 176, post-cardiotomy - 136, other vasodilatory/mixed shock - 199, and cardiac arrest - 101). Commonly reported responses include rapid improvement in systemic blood pressure, decline in concurrent catecholamine requirement, and increase in urine output; despite these effects, the mortality rates remained high.

CONCLUSION

In view of the limited clinical experience, and paucity of randomized controlled trials evaluating these drugs in pediatric population, currently no definitive recommendations on vasopressin/terlipressin use can be laid down. Nevertheless, available clinical data supports the use of vasopressin in critically ill children as a rescue therapy in refractory shock and cardiac arrest.

The use of Arginine Vasopressin in neonates following the Norwood procedure

BACKGROUND

Following the Norwood palliation, neonates may require an escalation of inotropic and vasoactive support. Arginine Vasopressin may be uniquely useful in supporting this population.

MATERIALS AND METHODS

A retrospective evaluation of neonates at this institution between November, 2007 and October, 2010 who received Arginine Vasopressin following the Norwood procedure. Data were recorded from the patient records at one hour prior to, and then 1, 2, 3, 4, 6, and 24 hours following Arginine Vasopressin initiation.

RESULTS

We included 28 neonates. The mean dose of Arginine Vasopressin was 0.0005 plus or minus 0.0003 units per kilogram per minute. There was an early response (less than 6 hours) characterised by an 8% increase in systolic blood pressure (p = 0.0004), a 100% increase in urine output (p = 0.02), and a 29% decrease in total fluid administration (p = 0.04). The late response (at 24 hours) revealed further increases in systolic blood pressure and urine output as well as a 53% decrease in serum lactate (p = 0.007) and increase in arterial pH from 7.36 to 7.45 (p less than 0.0001). These changes were not accompanied by increases in heart rate or inotrope score.

CONCLUSIONS

The initiation of Arginine Vasopressin in post-operative Norwood patients was temporally associated with an improvement in markers of perfusion including systolic blood pressure, urine output, lactate, and pH. Further studies are required to ascertain the efficacy of Arginine Vasopressin in this population.

Relative deficiency of arginine vasopressin in children after cardiopulmonary bypass

OBJECTIVE

To describe changes in plasma arginine vasopress in concentration in children following cardiopulmonary bypass and determine whether, in some patients, plasma arginine vasopressin remains relatively low despite hemodynamic instability.

DESIGN

Prospective observational study.

SETTING

Pediatric intensive care unit at a tertiary care university hospital.

PATIENTS

One hundred twenty patients ≤ 18 yrs of age undergoing open heart surgery requiring cardiopulmonary bypass at Children's Hospital of Michigan between January 2008 and January 2009.

INTERVENTIONS

Blood samples were collected before cardiopulmonary bypass and 4, 24, and 48 hrs after cardiopulmonary bypass for measurement of plasma arginine vasopressin concentration.

MEASUREMENTS AND MAIN RESULTS

Mean plasma arginine vasopressin (pg/mL) for all patients was 21 ± 63 before cardiopulmonary bypass and 80 ± 145, 43 ± 79, and 19 ± 25 at 4, 24, and 48 hrs, respectively, after cardiopulmonary bypass. Patients with plasma arginine vasopressin below the lower quartile (< 9.2 pg/mL) at 4 hrs after cardiopulmonary bypass (n = 29), labeled group A, were examined separately and compared with the rest of the study population, labeled group B. Mean plasma arginine vasopressin was 4.9 ± 2.6 in group A at 4 hrs after cardiopulmonary bypass, statistically unchanged from its baseline mean plasma arginine vasopressin of 5.0 ± 10.4 (p = .977). Mean plasma arginine vasopressin in group B was 104 ± 160 at 4 hrs after cardiopulmonary bypass. Mean plasma arginine vasopressin of group A was also significantly lower as compared with group B before and 24 and 48 hrs after cardiopulmonary bypass. Hemodynamics, inotrope score, and serum sodium did not differ between groups at any time point. Plasma arginine vasopressin was measured immediately before exogenous arginine vasopressin administration in 10 patients; only those (n = 3) with hemodynamic instability and relatively low plasma arginine vasopressin concentration (< 9.2 pg/mL) had notable hemodynamic improvement.

CONCLUSIONS

In some children undergoing open heart surgery, plasma arginine vasopressin concentration is relatively low at baseline and remains low after cardiopulmonary bypass regardless of hemodynamic stability and serum osmolality. These children are likely the optimal candidates for exogenous arginine vasopressin should hemodynamic compromise occur.

Preoperative pulmonary hemodynamics and assessment of operability: is there a pulmonary vascular resistance that precludes cardiac operation?

Preoperative pulmonary vascular disease remains an important risk factor for death or right-heart failure in selected children undergoing two-ventricle repair, single-ventricle palliation, or heart transplantation. Preoperative criteria for poor outcome after operation remain unclear. The purpose of this review is to critically assess both the historic and current data and make recommendations where appropriate. An extensive literature search was undertaken in October 2009. Data were analyzed by an expert multidisciplinary team and recommendations were made by consensus. PubMed was searched in October 2009. Data were analyzed and recommendations were made by consensus of a multidisciplinary team. In patients with suspected pulmonary vascular disease anticipating a two-ventricle repair, although preoperative testing via cardiac catheterization with vasodilators is reasonable, the preoperative parameters and the precise values of these parameters that best correlate with early and late outcome remain unclear. Further investigation is warranted in selected populations, such as the growing group of children with congenital heart disease complicated by chronic lung disease of prematurity, and in the developing world where patients may be more likely to present late with advanced pulmonary vascular disease. In patients with a functional single ventricle, there is growing evidence that mean pulmonary artery pressure of >15 mm Hg may be associated with both early and late mortality after the Fontan operation. The relationship of preoperative pulmonary hemodynamics to early and late morbidity remains to be defined. There most likely is a level of preoperative pulmonary vascular disease that puts an individual patient at increased risk for death or severe cyanosis after a bidirectional cavopulmonary anastomosis. It remains unclear, however, how to best assess this risk preoperatively. The limitations in obtaining an accurate assessment of pulmonary vascular disease in the complex single ventricle are discussed. In children awaiting cardiac transplantation with elevated pulmonary vascular disease of >6 U.m and/or transpulmonary gradient of >15 mm Hg, heart transplantation is deemed feasible in most transplant centers if the administration of inotropes or vasodilators can decrease the pulmonary vascular disease to <6 U.m or transpulmonary gradient to <15 mm Hg. In patients with preoperative pulmonary vascular disease, there may be contributing factors to the pulmonary vascular disease, such as the specifics of the cardiac lesion (atrioventricular valve regurgitation, low cardiac output), parenchymal and/or airway issues, and/or individual genetic predisposition. Amelioration of any reversible factors before operation and optimization of their management in the preoperative and postoperative period are recommended.

Vasoactive-inotropic score as a predictor of morbidity and mortality in infants after cardiopulmonary bypass

OBJECTIVE

Inotrope score has been proposed as a marker of illness severity after pediatric cardiac surgery despite a lack of data to support its use as such. The goal of this study was to determine the association between inotropic/vasoactive support and clinical outcome in infants after cardiac surgery.

DESIGN

Retrospective chart review.

SETTING

Dedicated pediatric cardiothoracic intensive care unit at an academic, tertiary care medical center.

PATIENTS

One hundred seventy-four patients 0 to 6 months of age admitted to the cardiothoracic intensive care unit after cardiac surgery with cardiopulmonary bypass between August 2007 and June 2008. Forty-three percent were neonates, and 39% had functional single ventricle physiology.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Hourly doses of all vasoactive medications were recorded for the first 48 hrs after admission to the cardiothoracic intensive care unit and a vasoactive-inotropic score was calculated. The maximum vasoactive-inotropic score level over the first 48 hrs was a good predictor of poor clinical outcome (death, cardiac arrest, mechanical circulatory support, renal replacement therapy, and/or neurologic injury). After controlling for diagnosis, high maximum vasoactive-inotropic score was strongly associated with a poor outcome with an adjusted odds ratio of 8.1 (95% confidence interval, 3.4-19.2; p < .001) compared with patients with a low maximum vasoactive-inotropic score. High vasoactive-inotropic score was also associated with prolonged cardiothoracic intensive care unit stay, duration of mechanical ventilation, and time to negative fluid balance.

CONCLUSIONS

The amount of cardiovascular support in the first 48 hrs after congenital heart surgery with cardiopulmonary bypass predicts eventual morbidity and mortality in young infants. The degree of support is best characterized by a maximum vasoactive-inotropic score obtained during this period. The usefulness of vasoactive-inotropic score as an independent predictor of clinical outcome in infants after cardiac surgery may have important implications for future cardiothoracic intensive care unit research.