Vasopressin infusion in children with catecholamine-resistant septic shock

Efficacy and safety of vasopressin and terlipressin in preterm neonates: a protocol for a systematic review

BACKGROUND

The use of vasoactive agents like arginine vasopressin (AVP) and terlipressin to treat hypotension or persistent pulmonary hypertension in critically ill preterm neonates is increasing. Therefore, a systematic review of the available data on dosing, efficacy and safety of AVP and terlipressin in this patient population appears beneficial.

METHODS

We will conduct a systematic review of the available evidence on the use of AVP and terlipressin for the treatment of hypotension or persistent pulmonary hypertension in preterm neonates. We will search Ovid MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Web of Science and Google Scholar from inception to March 2021. Two reviewers will independently screen titles and abstracts, review the full text of eligible studies, extract data, assess the risk of bias and judge the certainty of the evidence. Our primary outcome will be an (1) improvement of end-organ perfusion after initiation of AVP or terlipressin and (2) mortality prior to discharge. Our secondary outcomes will include (1) major neurosensory abnormality and (2) the occurrence of adverse events.

DISCUSSION

The currently available evidence on the efficacy and safety of AVP and terlipressin in preterm neonates is limited. Yet, evidence on the pharmacology of these drugs and the pathophysiology of vasoplegic shock support the biological plausibility for their clinical effectiveness in this population. Therefore, we aim to address this gap concerning the use of vasopressin and terlipressin among critically ill preterm neonates.

TRIAL REGISTRATION

This protocol has been submitted for registration to the international database of prospectively registered systematic reviews (PROSPERO, awaiting registration number).

Use of vasopressin in neonatal hypertrophic obstructive cardiomyopathy: case series

OBJECTIVE

To determine the effect of vasopressin on arterial blood pressure in infants with neonatal hypertrophic obstructive cardiomyopathy (HOCM).

STUDY DESIGN

Retrospective case study in Neonatal ICU involving six infants; five born to mothers with diabetes mellitus (mean gestational age 37.5 ± 0.9 weeks). Vasopressin infusion was started at a mean dose of 0.3 ± 0.2 mU/kg/min.

RESULT

Initiation of vasopressin was followed by improved mean (p = 0.004), systolic (p = 0.028), and diastolic (p = 0.009) arterial pressure within 2 h. Heart rate (p = 0.025) and oxygen requirement (p = 0.021) also declined after initiation. Serum sodium declined initially and recovered by 72 h (p = 0.017).

CONCLUSION

Although there is limited experience with vasopressin use in neonatal HOCM, our case series suggests it may be beneficial for improving systemic hypotension and stabilization of hemodynamics. The potential for hyponatremia is high, necessitating careful fluid/electrolyte management. A prospective randomized trial is necessary to confirm safety and efficacy of vasopressin treatment in neonatal HOCM.

Inotropes for Preterm Infants: 50 Years on Are We Any Wiser?

For almost half a century, inotropes have been administered to preterm infants with the ultimate goal of increasing their blood pressure. A number of trials, the majority of which focused on dopamine administration, have demonstrated increased blood pressure following inotrope administration in preterm infants and have led to continued use of inotropes in our neonatal units. We have also seen an increase in the number of potential agents available to the clinician. However, we now know that hypotension is a much broader concept than blood pressure alone, and our aim should instead be focused on improving end organ perfusion, specifically cerebral perfusion. Only a limited number of studies have incorporated the organ-relevant hemodynamic changes and long-term outcomes when assessing inotropic effects in neonates, the majority of which are observational studies or have a small sample size. In addition, important considerations, including the developing/maturing adrenergic receptors, polymorphisms of these receptors, and other differences in the pharmacokinetics and pharmacodynamics of preterm infants, are only recently being recognized. Certainly, there remains huge variation in practice. The lack of well-conducted randomized controlled trials addressing these relevant outcomes, along with the difficulty executing such RCTs, leaves us with more questions than answers. This review provides an overview of the various inotropic agents currently being used in the care of preterm infants, with a particular focus on their organ/cerebral hemodynamic effects both during and after transition.

American College of Critical Care Medicine Clinical Practice Parameters for Hemodynamic Support of Pediatric and Neonatal Septic Shock

OBJECTIVES

The American College of Critical Care Medicine provided 2002 and 2007 guidelines for hemodynamic support of newborn and pediatric septic shock. Provide the 2014 update of the 2007 American College of Critical Care Medicine "Clinical Guidelines for Hemodynamic Support of Neonates and Children with Septic Shock."

DESIGN

Society of Critical Care Medicine members were identified from general solicitation at Society of Critical Care Medicine Educational and Scientific Symposia (2006-2014). The PubMed/Medline/Embase literature (2006-14) was searched by the Society of Critical Care Medicine librarian using the keywords: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, extracorporeal membrane oxygenation, and American College of Critical Care Medicine guidelines in the newborn and pediatric age groups.

MEASUREMENTS AND MAIN RESULTS

The 2002 and 2007 guidelines were widely disseminated, translated into Spanish and Portuguese, and incorporated into Society of Critical Care Medicine and American Heart Association/Pediatric Advanced Life Support sanctioned recommendations. The review of new literature highlights two tertiary pediatric centers that implemented quality improvement initiatives to improve early septic shock recognition and first-hour compliance to these guidelines. Improved compliance reduced hospital mortality from 4% to 2%. Analysis of Global Sepsis Initiative data in resource rich developed and developing nations further showed improved hospital mortality with compliance to first-hour and stabilization guideline recommendations.

CONCLUSIONS

The major new recommendation in the 2014 update is consideration of institution-specific use of 1) a "recognition bundle" containing a trigger tool for rapid identification of patients with septic shock, 2) a "resuscitation and stabilization bundle" to help adherence to best practice principles, and 3) a "performance bundle" to identify and overcome perceived barriers to the pursuit of best practice principles.

The Role of Terlipressin in Pediatric Septic Shock: A Review of the Literature and Personal Experience

Vasopressin and its synthetic analog terlipressin are potent vasopressors that could be useful in vasodilatory septic shock. In septic adults, vasopressin/terlipressin have been shown to increase mean arterial pressure and to decrease the necessity for catecholamines. Moreover, low doses of vasopressin (or terlipressin) increase urine output and ameliorate oxygenation. Although pediatric septic shock is more often hypodynamic, both vasopressin and terlipressin have proved to be effective in restoring blood pressure or increasing the diuresis in this setting. The purpose of this review is to summarize the physiology of vasopressin and to report the available evidence for the use of vasopressin or terlipressin in pediatric septic shock in order to make best use in this population. We also report our experience with the continuous infusion of terlipressin in two pediatric patients who developed catecholamine refractory septic shock.

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.

Pediatric Sepsis Guidelines: Summary for resource-limited countries

Justification:

Pediatric sepsis is a commonly encountered global issue. Existing guidelines for sepsis seem to be applicable to the developed countries, and only few articles are published regarding application of these guidelines in the developing countries, especially in resource-limited countries such as India and Africa.

Process:

An expert representative panel drawn from all over India, under aegis of Intensive Care Chapter of Indian Academy of Pediatrics (IAP) met to discuss and draw guidelines for clinical practice and feasibility of delivery of care in the early hours in pediatric patient with sepsis, keeping in view unique patient population and limited availability of equipment and resources. Discussion included issues such as sepsis definitions, rapid cardiopulmonary assessment, feasibility of early aggressive fluid therapy, inotropic support, corticosteriod therapy, early endotracheal intubation and use of positive end expiratory pressure/mechanical ventilation, initial empirical antibiotic therapy, glycemic control, and role of immunoglobulin, blood, and blood products.

Objective:

To achieve a reasonable evidence-based consensus on the basis of published literature and expert opinion to formulating clinical practice guidelines applicable to resource-limited countries such as India.

Recommendations:

Pediatric sepsis guidelines are presented in text and flow chart format keeping resource limitations in mind for countries such as India and Africa. Levels of evidence are indicated wherever applicable. It is anticipated that once the guidelines are used and outcomes data evaluated, further modifications will be necessary. It is planned to periodically review and revise these guidelines every 3–5 years as new body of evidence accumulates.

Management of septic shock

Septic shock is an important cause of mortality in children with sepsis. The incidence of septic shock is 2-4% of admissions in western pediatric intensive care units and 40%-67% for Indian PICUs. Early goal-directed resuscitation that includes aggressive fluid resuscitation of up to 60 mL/kg as boluses of 20 mL/kg by IV push, to achieve desired heart rates and blood pressure, has emerged as mainstay of treatment in the initial stage. Crystalloids are the preferred fluids, while colloids may be used in some situations. Fluid refractory shock warrants use of vasoactive drugs. Dopamine is the first choice. Dobutamine and low dose epinephrine are the preferred inotropic drugs while nor-epinephrine is a vasopressor. Children with cold shock and normal blood pressure may benefit from nitrosodilators like nitroprusside and nitroglycerine. Inodilators such as milrinone are also useful in this situation. Targeting clinical therapeutic end-points assists the management. Good supportive care is also essential for improving the outcomes.

Part 10: Pediatric basic and advanced life support: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

Note From the Writing Group: Throughout this article, the reader will notice combinations of superscripted letters and numbers (eg, “Family Presence During ResuscitationPeds-003”). These callouts are hyperlinked to evidence-based worksheets, which were used in the development of this article. An appendix of worksheets, applicable to this article, is located at the end of the text. The worksheets are available in PDF format and are open access.

Low-dose vasopressin infusion therapy for refractory hypotension in ELBW infants

BACKGROUND

Severe hypotension in infants, especially in preterm infants, is associated with poor neurological outcome and high mortality. In adults, low-dose vasopressin (arginine vasopressin: AVP) infusion therapy has been effective for treating hypotension that is refractory to vasopressors and inotropes.

METHODS

The effects of AVP infusion therapy for refractory hypotension were retrospectively evaluated in extremely low-birthweight infants. Between January 2002 and November 2005, 22 infants with refractory hypotension treated with low-dose AVP infusion were reviewed. The average birthweight was 658 g (+/-142 g), and the average gestational age was 24.9 weeks (+/-1.4). The changes in blood pressure, urinary output, and other parameters in response to AVP therapy were analyzed in all the infants.

RESULTS

After AVP infusion, systolic blood pressure increased from 30 mmHg to 43 mmHg (P < 0.0001), and the diastolic pressure increased from 15 mmHg to 24 mmHg (P < 0.0001). The urine output dramatically increased from 1.5 mL/kg per h to 4.0 mL/kg per h (P < 0.0001). AVP infusion, however, was not effective in four of the 22 patients (18%). The sodium concentration in the serum decreased mildly after administration. In six patients the serum sodium concentration decreased below 130 mEq/L. Severe mitral regurgitation was observed in two patients. Three infants showed a transient decrease in the platelet count during AVP infusion.

CONCLUSIONS

Low-dose AVP therapy should be considered as rescue therapy when high-dose catecholamine therapy and/or steroid administration do not produce sufficient increase in the blood pressure. Further investigations are required to prove the efficacy and safety of AVP infusion therapy in preterm infants.

Clinical practice parameters for hemodynamic support of pediatric and neonatal septic shock: 2007 update from the American College of Critical Care Medicine

BACKGROUND

The Institute of Medicine calls for the use of clinical guidelines and practice parameters to promote "best practices" and to improve patient outcomes.

OBJECTIVE

2007 update of the 2002 American College of Critical Care Medicine Clinical Guidelines for Hemodynamic Support of Neonates and Children with Septic Shock.

PARTICIPANTS

Society of Critical Care Medicine members with special interest in neonatal and pediatric septic shock were identified from general solicitation at the Society of Critical Care Medicine Educational and Scientific Symposia (2001-2006).

METHODS

The Pubmed/MEDLINE literature database (1966-2006) was searched using the keywords and phrases: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, extracorporeal membrane oxygenation (ECMO), and American College of Critical Care Medicine guidelines. Best practice centers that reported best outcomes were identified and their practices examined as models of care. Using a modified Delphi method, 30 experts graded new literature. Over 30 additional experts then reviewed the updated recommendations. The document was subsequently modified until there was greater than 90% expert consensus.

RESULTS

The 2002 guidelines were widely disseminated, translated into Spanish and Portuguese, and incorporated into Society of Critical Care Medicine and AHA sanctioned recommendations. Centers that implemented the 2002 guidelines reported best practice outcomes (hospital mortality 1%-3% in previously healthy, and 7%-10% in chronically ill children). Early use of 2002 guidelines was associated with improved outcome in the community hospital emergency department (number needed to treat = 3.3) and tertiary pediatric intensive care setting (number needed to treat = 3.6); every hour that went by without guideline adherence was associated with a 1.4-fold increased mortality risk. The updated 2007 guidelines continue to recognize an increased likelihood that children with septic shock, compared with adults, require 1) proportionally larger quantities of fluid, 2) inotrope and vasodilator therapies, 3) hydrocortisone for absolute adrenal insufficiency, and 4) ECMO for refractory shock. The major new recommendation in the 2007 update is earlier use of inotrope support through peripheral access until central access is attained.

CONCLUSION

The 2007 update continues to emphasize early use of age-specific therapies to attain time-sensitive goals, specifically recommending 1) first hour fluid resuscitation and inotrope therapy directed to goals of threshold heart rates, normal blood pressure, and capillary refill 70% and cardiac index 3.3-6.0 L/min/m.

Recent advances in sepsis and septic shock

Sepsis remains a common problem in all age groups. Recently surviving sepsis campaign has taken up a worldwide initiative by publishing international guidelines 2008 with a hope to disseminate information regarding management of sepsis for all age groups. This article presents a review of recent advances as they apply to pediatric age group supported by the available evidence with reference to standard definitions of pediatric sepsis and septic shock and management in the emergency room and pediatric intensive care unit.

Vasopressin in pediatric shock and cardiac arrest

OBJECTIVE

To review the physiology and the published literature on the role of vasopressin in shock in children.

DATA SOURCE

We searched MEDLINE (1966-2007), EMBASE (1980-2007), and the Cochrane Library, using the terms vasopressin, terlipressin, and shock and synonyms or related terms for relevant studies in pediatrics. We searched the online ISRCTN-Current Controlled Trials registry for ongoing trials. We reviewed the reference lists of all identified studies and reviews as well as personal files to identify other published studies.

RESULTS

Beneficial effects have been reported in vasodilatory shock and asystolic cardiac arrest in adults. Solid evidence for vasopressin use in children is scant. Observational studies have reported an improvement in blood pressure and rapid weaning off catecholamines during administration of low-dose vasopressin. Dosing in children is extrapolated from adult studies.

CONCLUSIONS

Vasopressin offers promise in shock and cardiac arrest in children. However, in view of the limited experience with vasopressin, it should be used with caution. Results of a double-blind, randomized controlled trial in children with vasodilatory shock will be available soon.

Clinical impact of vasopressin infusion on hemodynamics, liver and renal function in pediatric patients

OBJECTIVE

To study effects of vasopressin on hemodynamic, clinical, and laboratory variables in children with advanced vasodilatory shock.

DESIGN AND SETTING

Retrospective study in a multidisciplinary tertiary pediatric critical care unit.

PATIENTS AND PARTICIPANTS

Patients (n = 117; 32 noncardiac, 85 postcardiac surgery) requiring intravenous vasopressin infusion longer than 60 min for advanced shock (January 2004 to December 2005).

INTERVENTIONS

Vasopressin infusion (n =157).

MEASUREMENTS AND RESULTS

Both cardiac and noncardiac patients showed a significant decrease in inotrope requirement without change in central venous saturation or lactate during infusion. Both groups had increased urea and creatinine and decreased urine output with longer duration/higher cumulative dose of vasopressin. There was a significant increase in conjugated bilirubin level in the noncardiac group during vasopressin infusion; noncardiac patients showed higher AST levels with higher cumulative dose or longer duration of infusion. Postcardiac surgical patients showed a trend towards normal INR values which persisted after vasopressin infusion. Platelet counts were significantly lower during infusion in both groups.

CONCLUSIONS

Vasopressin infusion improved the hemodynamic state in advanced shock without compromising cardiac function. Urine output and creatinine levels were adversely affected but were reversible. This effect was more pronounced with higher dose or duration of infusion. There was no major effect on liver function but a significant reduction in platelet counts. These data suggest that vasopressin is useful in states of vasodilatory shock with limitations regarding to its adverse renal effects and on platelet counts.

Arginine-vasopressin in neonates with vasodilatory shock after cardiopulmonary bypass

Successful therapy of vasodilatory shock in adults and children with arginine-vasopressin (AVP) has been reported previously. Data on the use of vasopressin in neonates is limited. This retrospective study reports the effects of AVP-treatment in neonates with catecholamine-resistant systemic vasodilatation after cardiopulmonary bypass. From March 2003 through December 2005, 172 neonates underwent open-heart surgery, 17 developed vasopressor-resistant hypotension and were treated with AVP. Thirteen patients had a stage I palliation of single ventricle, two had a Ross-operation and two had an arterial switch operation. All patients received multiple traditional inotropes and vasopressors prior to administration of AVP. AVP was started at median 0.0001 U x kg(-1) x min(-1) (range 0.00005-0.0002) and titrated up to a maximum of median 0.0003 U x kg(-1) x min(-1) (range 0.0001-0.001). AVP led to a significant increase in blood pressure (from 49+/-8 mmHg to 69+/-7 mmHg) and the requirement of traditional vasopressors decreased significantly. No peripheral vasoconstriction or ischemia was observed. Four of 13 patients, all with single ventricle palliation, died. In two patients death occurred due to additional complications 6 days after AVP was discontinued. One patient, who was still on AVP, died 42 hours postoperatively after prolonged hypoxemia not responding to inhaled nitric oxide. One patient arrested on the third postoperative day when AVP was almost weaned.

CONCLUSION

In neonates with vasodilatory shock after cardiopulmonary bypass AVP is a potent agent to increase blood pressure when traditional vasopressors are failing.

Arginine-vasopressin in catecholamine-refractory septic versus non-septic shock in extremely low birth weight infants with acute renal injury

Introduction

The aim of this study was to assess the efficacy of arginine-vasopressin (AVP) as a rescue therapy in catecholamine-refractory septic and non-septic shock in extremely low birth weight (ELBW) infants with acute renal injury.

Methods

Prospective assessment of AVP therapy in three ELBW infants with catecholamine-refractory septic shock and acute renal injury (mean birth weight 600 ± 30 g) and three ELBW infants with non-septic shock and acute renal injury (mean birth weight 770 ± 110 g) at a University hospital. The main outcome measures were restoration of blood pressure with adequate organ perfusion and survival at discharge.

Results

In all three ELBW infants with catecholamine-resistant septic shock, systemic arterial blood pressure increased substantively with restoration of urine output after AVP administration (dosage, 0.035 to 0.36 U/kg/h; length, 70 ± 21 hours). In the three ELBW infants with non-septic shock, only a transient stabilization in mean arterial pressure with restoration of urine output was observed after AVP therapy (dosage, 0.01 to 0.36 U/kg/h; length, 30 ± 16 hours). The mortality rate was 1/3 in the sepsis group versus 3/3 in the non-septic group.

Conclusion

AVP may be a promising rescue therapy in catecholamine-resistant shock in ELBW infants with acute renal injury. Larger prospective clinical trials are warranted to assess the efficacy and safety of AVP as a pressor adjunct in septic versus non-septic shock in ELBW infants.

Serial circulating vasopressin levels in children with septic shock

BACKGROUND

Septic shock is an important cause of death in pediatric intensive care units. Initial evaluations have shown that vasopressin may have a role in catecholamine refractory shock in adults. It is important to determine whether children with septic shock have deficiency of vasopressin. This will help in defining the role of vasopressin in septic shock.

DESIGN

Prospective cohort study.

SETTING

Pediatric intensive care unit of a tertiary care hospital in north India.

PATIENTS

Patients were children with septic shock, and controls were children with sepsis but no shock.

STUDY DESIGN

Vasopressin levels in plasma were determined by enzyme-linked immunosorbent assay for children with septic shock at diagnosis (baseline) and thereafter at 24, 48, and 96 hrs to determine the time trends. The baseline vasopressin values for children with septic shock were compared with those for children without shock.

RESULTS

The median (95% confidence interval) vasopressin level at baseline in children with septic shock was 116 (63.3-130.7) pg/mL, and in children with sepsis but no shock it was 106 (61.7-131.77) pg/mL. The median value for survivors was 76 (44.6-130.9) pg/mL, and for nonsurvivors, 118 (81.7-259) pg/mL (p = .16). The serial values also did not show any significant changes; the values at 24 hrs (n = 17), 48 hrs (n = 16), and 96 hrs (n = 15) were 105 (76.1-125.9), 105 (41.4-155.5), and 109.5 (54.9-154.8) pg/mL, respectively.

CONCLUSIONS

The results of our study suggest that vasopressin levels are elevated in children with septic shock and that serial values up to 96 hrs do not show any decline.

Rescue treatment with terlipressin in children with refractory septic shock: a clinical study

INTRODUCTION

Refractory septic shock has dismal prognosis despite aggressive therapy. The purpose of the present study is to report the effects of terlipressin (TP) as a rescue treatment in children with catecholamine refractory hypotensive septic shock.

METHODS

We prospectively registered the children with severe septic shock and hypotension resistant to standard intensive care, including a high dose of catecholamines, who received compassionate therapy with TP in nine pediatric intensive care units in Spain, over a 12-month period. The TP dose was 0.02 mg/kg every four hours.

RESULTS

Sixteen children (age range, 1 month-13 years) were included. The cause of sepsis was meningococcal in eight cases, Staphylococcus aureus in two cases, and unknown in six cases. At inclusion the median (range) Pediatric Logistic Organ Dysfunction score was 23.5 (12-52) and the median (range) Pediatric Risk of Mortality score was 24.5 (16-43). All children had been treated with a combination of at least two catecholamines at high dose rates. TP treatment induced a rapid and sustained improvement in the mean arterial blood pressure that allowed reduction of the catecholamine infusion rate after one hour in 14 out of 16 patients. The mean (range) arterial blood pressure 30 minutes after TP administration increased from 50.5 (37-93) to 77 (42-100) mmHg (P < 0.05). The noradrenaline infusion rate 24 hours after TP treatment decreased from 2 (1-4) to 1 (0-2.5) microg/kg/min (P < 0.05). Seven patients survived to the sepsis episode. The causes of death were refractory shock in three cases, withdrawal of therapy in two cases, refractory arrhythmia in three cases, and multiorgan failure in one case. Four of the survivors had sequelae: major amputations (lower limbs and hands) in one case, minor amputations (finger) in two cases, and minor neurological deficit in one case.

CONCLUSION

TP is an effective vasopressor agent that could be an alternative or complementary therapy in children with refractory vasodilatory septic shock. The addition of TP to high doses of catecholamines, however, can induce excessive vasoconstriction. Additional studies are needed to define the safety profile and the clinical effectiveness of TP in children with septic shock.