Hyponatremia during arginine vasopressin therapy in children following cardiac surgery

Serum Sodium Concentration During Arginine Vasopressin Infusion in Critically Ill Children

BACKGROUND

Intravenous arginine vasopressin is increasingly used for the treatment of critically ill children. It bears the risk of hyponatraemia with potential severe long-term sequelae, but data on hyponatraemia as a side effect of continuous vasopressin infusion for paediatric intensive care patients is scarce.

METHODS

In this retrospective analysis performed at a tertiary care paediatric intensive care unit with 2000 annual admissions, patients were included if they were treated with intravenous vasopressin between 2016 and 2022. Baseline sodium concentrations, lowest sodium concentrations during arginine vasopressin treatment, and time to lowest sodium concentration (nadir) were derived.

RESULTS

In total, 170 patients with a median age of 4 months [interquartile range, IQR, 0-33] were included, 92.4% underwent surgery, and 28.8% died. Median arginine vasopressin dose rate was 0.027 IU/kg/h [0.019-0.036] and arginine vasopressin was started 3.2 [0-26] h after intensive care admission. Median arginine vasopressin application duration was 13.6 h [6.2-32.6]. Baseline sodium was 141 mmol/L [138-145], and lowest median sodium during arginine vasopressin infusion was 137 mmol/L [132-141] (nadir at 8.4 h [1.0-28.1] after arginine vasopressin start). Hyponatraemia (<135 mmol/L) occurred in 38.2% of patients during AVP treatment, and physicians administered a median of 10.2 mmol/kg/d [6.2-16.4] sodium during arginine vasopressin therapy.

CONCLUSIONS

Under arginine vasopressin infusion, hyponatraemia was common, although high daily doses of sodium were administered to keep the serum values in physiologic ranges. This emphasises the need for close electrolyte monitoring and sodium substitution in children and adolescents under arginine vasopressin treatment to avoid hyponatraemia and related sequelae.

Evaluation of Hyponatremia in Infants on Vasopressin Therapy

OBJECTIVE

Vasopressin has systemic vasoconstrictive yet pulmonary vasodilatory effects, making it an ideal agent for hypotension management in infants with congenital diaphragmatic hernia (CDH)-associated pulmonary hypertension. The side effects of vasopressin in this population, such as hyponatremia, are understudied. This study aims to characterize the effect of vasopressin on sodium concentrations in infants with and without CDH.

METHODS

This was a retrospective review of patients who received vasopressin while admitted to a level IV neonatal intensive care unit. The primary outcome was the incidence of hyponatremia (blood sodium <135 mmol/L) during vasopressin therapy. Secondary outcomes included time to hyponatremia, dose and duration of vasopressin, incidence of severe hyponatremia (blood sodium <125 mmol/L), and hypertonic saline use. Both blood serum and blood gas sample sodium concentrations were used to compare CDH vs non-CDH patients.

RESULTS

The average difference between baseline and lowest blood sodium was significant for both CDH and non-CDH patients for all samples (p < 0.001). There was no significant difference in the primary outcome, nor in the secondary outcomes of time to hyponatremia or duration of vasopressin infusion. The average dose of vasopressin was higher in the CDH vs non-CDH group (p = 0.018). The incidences of severe hyponatremia and hypertonic saline use were greater in the CDH vs non-CDH group for patients who had blood serum sodium samples collected (p = 0.049 and p = 0.033, respectively).

CONCLUSIONS

This study showed that severe hyponatremia occurred more frequently in CDH vs non-CDH patients. Extreme caution is necessary when managing total body sodium in patients with CDH.

Postoperative free water administration is associated with dysnatremia after congenital heart disease surgery in infants

Dysnatremia after congenital heart disease (CHD) surgery is common. European guidelines on intraoperative fluid therapy in children recommend isotonic solutions to avoid hyponatremia, but prolonged cardiopulmonary bypass and administration of high sodium-containing solutions (i.e., blood products and sodium bicarbonate) are associated with postoperative hypernatremia. The aim of the study was to describe fluid composition prior to and during the development of postoperative dysnatremia. A retrospective observational, single-center study including infants undergoing CHD surgery. Demographics and clinical characteristics were registered. Highest and lowest plasma sodium values were recorded and associations with perioperative fluid administration, blood products, crystalloids, and colloids were explored in relation to three perioperative periods. Postoperative dysnatremia occurred in nearly 50% of infants within 48 h after surgery. Hypernatremia was mainly associated with administration of blood products (median [IQR]: 50.5 [28.4-95.5] vs. 34.5 [18.5-61.1] mL/kg; p = 0.001), and lower free water load (1.6 [1.1-2.2] mL/kg/h; p = 0.01). Hyponatremia was associated with a higher free water load (2.3 [1.7-3.3] vs. 1.8 [1.4-2.5] mL/kg/h; p = 0.001) and positive fluid balance. On postoperative day 1, hyponatremia was associated with higher volumes of free water (2.0 [1.5-2.8] vs. 1.3 [1.1-1.8] mL/kg/h; p < 0.001) and human albumin, despite a larger diuresis and more negative daily fluid balance. Postoperative hyponatremia occurred in 30% of infants despite restrictive volumes of hypotonic maintenance fluid, whereas hypernatremia was mainly associated with blood product transfusion. Individualized fluid therapy, with continuous reassessment to reduce the occurrence of postoperative dysnatremia is mandatory in pediatric cardiac surgery. Prospective studies to evaluate fluid therapy in pediatric cardiac surgery patients are warranted.

Vasopressin-Induced Hyponatremia in Infants Following Cardiovascular Surgery

BACKGROUND

Vasopressin is increasingly used in infants following cardiac surgery. Hyponatremia is a noted adverse event, but incidence and risk factors remain undefined.

OBJECTIVE

The primary objective was to identify the incidence of vasopressin-induced hyponatremia. Secondary objectives included comparing baseline and change in serum sodium concentrations between infants receiving vasopressin with and without hyponatremia, and comparing vasopressin dose, duration, and clinical characteristics in those with and without hyponatremia.

METHODS

This Institutional Review Board-approved, retrospective case-control study included infants <6 months following cardiac surgery receiving vasopressin for ≥6 hours at a tertiary care, academic hospital. Patients who developed hyponatremia, cases, were matched to controls in a 1:2 fashion. Demographics and clinical characteristics were collected. Descriptive and inferential statistics were employed. A conditional logistic regression was used to assess odds of hyponatremia.

RESULTS

Of the included 142 infants, 20 (14.1%) developed hyponatremia and were matched with 40 controls. There was significant difference in median nadir between controls and cases, 142.0 versus 128.5 mEq/L (<0.001). A significantly higher number of cases received corticosteroids, loop diuretics, and chlorothiazide versus controls. The regression analysis demonstrated that each additional hour of vasopressin increased the odds of developing hyponatremia by 5% (adjusted odds ratio 1.05 [confidence interval 1-1.1]).

CONCLUSIONS AND RELEVANCE

Vasopressin-induced hyponatremia incidence was <15%. Vasopressin duration was independently associated with hyponatremia development.

Post-operative dysnatremia is associated with adverse early outcomes after surgery for congenital heart disease

BACKGROUND

Dysnatremia is a common disorder in critically ill surgical children. The study's aim is to determine the prevalence of dysnatremia and its association with outcomes after surgery for congenital heart disease (CHD).

METHODS

This is a single-center retrospective cohort study of children <18 years of age undergoing surgery for CHD between January 2012 and December 2014. Multivariable logistic regression analysis was used to evaluate the relationship between dysnatremia and outcomes during the perioperative period. A total of 1345 encounters met the inclusion criteria.

RESULTS

The prevalence of pre- and post-operative dysnatremia were 10.2% and 47.1%, respectively. Hyponatremia occurred in 19.1%, hypernatremia in 25.6%. Hypernatremia at 24, 48, and 72 h post-operative was associated with increased hospital mortality (odds ratios (OR) [95% confidence intervals (CI)] 3.08 [1.16-8.17], p = 0.024; 4.35 [1.58-12], p = 0.0045; 4.14 [1.32-12.97], p = 0.0148, respectively. Hypernatremia was associated with adverse neurological events 3.39 [1.12-10.23], p = 0.0302 at 48 h post-operative. Hyponatremia was not associated with any adverse outcome in our secondary analysis.

CONCLUSIONS

Post-operative dysnatremia is a common finding in this heterogeneous cohort of pediatric cardiac-surgical patients. Hypernatremia was more prevalent than hyponatremia and was associated with adverse early post-operative outcomes.

IMPACT

Our study has shown that dysnatremia was highly prevalent in children after congenital heart surgery with hypernatremia associated with adverse outcomes including mortality. It is important to understand fluid and sodium regulation in the post-operative period in children with congenital heart disease to better address fluid overload and associated electrolyte imbalances and acute kidney injury. While clinicians are generally very aware of the importance of hyponatremia in critically ill children, similar attention should be given to hypernatremia in this population.

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.

Postoperative dysnatremia in infants after open-heart surgery occurs frequently and is associated with prolonged intensive care length of stay

BACKGROUND

Dysnatremia after surgery for congenital heart disease (CHD) is well known and has been associated with prolonged pediatric intensive care unit length of stay (PICU-LOS). Fluctuations in plasma sodium levels occur perioperatively. The primary aim of the study was to evaluate the occurrence of dysnatremia during the first 48 h after surgery and whether it was associated with PICU-LOS. The secondary aim was to evaluate if the degree of sodium fluctuations was associated with PICU-LOS.

METHODS

A retrospective observational, single-center study including infants undergoing surgery for CHD. The highest and lowest plasma sodium value was registered for the prespecified time periods. PICU-LOS was analyzed in relation to the occurrence of dysnatremia and the degree of plasma sodium fluctuations. The occurrence of dysnatremia was evaluated in relation to surgical procedure and fluid administration.

RESULTS

Two hundred and thirty infants who underwent 249 surgical procedures were included. Dysnatremia developed in more than 60% within 48 h after surgery. Infants with normonatremia had a 40%-50% shorter PICU-LOS among children in RACHS-1 category 3-6, compared with infants developing either hypo- or hyper-/hyponatremia within 48 h after surgery (p = .006). Infants who had a decline of plasma sodium >11 mmol/L had almost double the PICU-LOS compared to those with a decline of <8 mmol/L.

CONCLUSION

Dysnatremias were common after surgery for CHD and associated with prolonged PICU-LOS. The degree of decline in plasma sodium was significantly associated with PICU-LOS. Fluid administration both in terms of volume and components (blood products and crystalloids) as well as diuresis were related to the occurrence of dysnatremias.

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.

A systematic review of the evidence supporting post-operative medication use in congenital heart disease

BACKGROUND

Targeted drug development efforts in patients with CHD are needed to standardise care, improve outcomes, and limit adverse events in the post-operative period. To identify major gaps in knowledge that can be addressed by drug development efforts and provide a rationale for current clinical practice, this review evaluates the evidence behind the most common medication classes used in the post-operative care of children with CHD undergoing cardiac surgery with cardiopulmonary bypass.

METHODS

We systematically searched PubMed and EMBASE from 2000 to 2019 using a controlled vocabulary and keywords related to diuretics, vasoactives, sedatives, analgesics, pulmonary vasodilators, coagulation system medications, antiarrhythmics, steroids, and other endocrine drugs. We included studies of drugs given post-operatively to children with CHD undergoing repair or palliation with cardiopulmonary bypass.

RESULTS

We identified a total of 127 studies with 51,573 total children across medication classes. Most studies were retrospective cohorts at single centres. There is significant age- and disease-related variability in drug disposition, efficacy, and safety.

CONCLUSION

In this study, we discovered major gaps in knowledge for each medication class and identified areas for future research. Advances in data collection through electronic health records, novel trial methods, and collaboration can aid drug development efforts in standardising care, improving outcomes, and limiting adverse events in the post-operative period.

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.

An evidence-based review of the use of vasoactive and inotropic medications in post-operative paediatric patients after cardiac surgery with cardiopulmonary bypass from 2000 to 2020

BACKGROUND

Infants with moderate-to-severe CHD frequently undergo cardiopulmonary bypass surgery in childhood. Morbidity and mortality are highest in those who develop post-operative low cardiac output syndrome. Vasoactive and inotropic medications are mainstays of treatment for these children, despite limited evidence supporting their use.

METHODS

To help inform clinical practice, as well as the conduct of future trials, we performed a systematic review of existing literature on inotropes and vasoactives in children after cardiac surgery using the PubMed and EMBASE databases. We included studies from 2000 to 2020, and the patient population was defined as birth - 18 years of age. Two reviewers independently reviewed studies to determine final eligibility.

RESULTS

The final analysis included 37 papers. Collectively, selected studies reported on 12 different vasoactive and inotropic medications in 2856 children. Overall evidence supporting the use of these drugs in children after cardiopulmonary bypass was limited. The majority of studies were small with 30/37 (81%) enrolling less than 100 patients, 29/37 (78%) were not randomised, and safety and efficacy endpoints differed widely, limiting the ability to combine data for meta-analyses.

CONCLUSION

Vasoactive and inotropic support remain critical parts of post-operative care for children after cardiopulmonary bypass surgery. There is a paucity of data for the selection and dosing of vasoactives and inotropes for these patients. Despite the knowledge gaps that remain, numerous recent innovations create opportunities to rethink the conduct of clinical trials in this high-risk population.

Hyponatremia With Intravenous Sulfamethoxazole/Trimethoprim in Children

Background: Intravenous (IV) sulfamethoxazole/trimethoprim (SMX/TMP) has been associated with hyponatremia in adults. Objective: The primary objective was to identify the number of patients with a serum sodium <135 mEq/L. Secondary objectives between the hyponatremic versus nonhyponatremic groups included demographic comparisons, median serum sodium concentrations, SMX/TMP cumulative dose, number of diuretics, and other medications causing hyponatremia. Methods: This was a retrospective study of children <18 years receiving IV SMP/TMX. Comparisons were conducted via Mann-Whitney-Wilcoxon and Mantel-Haenszel χ² tests with an a priori P value <0.05. Results: Sixty-one patients received 66 total courses; 20 courses (30.3%) were associated with hyponatremia with a decrease in the median nadir serum sodium concentration of 133 and 138 mEq/L in the hyponatremic and nonhyponatremic groups, respectively (P<0.001). The median age (interquartile range) was lower in the hyponatremic versus nonhyponatremic group, but this was not statistically significant: 0.6 (0.1-5.5) versus 3.9 (0.3-11.0) years; P=0.077. There was no significant difference in the median cumulative dose (mg/kg) between groups; P=0.104. In addition, there was a significant difference in the number of children in the hyponatremic versus nonhyponatremic groups receiving diuretics (16 [80.0%] vs 23 [50.0%], P=0.023) and other medications that cause hyponatremia (7 [35.0%] vs 5 [10.9%], P=0.034), respectively. Furosemide was noted to be the medication most associated with hyponatremia. Conclusion and Relevance: Approximately one-third administered IV SMX/TMP developed hyponatremia. Concomitant furosemide administration was one of the most common risk factors. Clinicians should be aware of this potential adverse event when initiating IV SMX/TMP in children.

Concurrent Use of Calcium Chloride and Arginine Vasopressin Infusions in Pediatric Patients with Acute Cardiocirculatory Failure

Acute heart failure (AHF) can cause low cardiac output and poor end-organ perfusion. Inotropic agents along with vasodilators can improve organ perfusion. Arginine vasopressin (AVP) and calcium chloride (CaCl) infusions are increasingly being used in low cardiac output states in pediatric AHF. We retrospectively reviewed 77 patients (0-18 years) with AHF admitted between January 2014 and May 2017 who received concurrent AVP and CaCl infusions. Surrogates of cardiac output and organ perfusion included hemodynamic vital signs, laboratory parameters, and urine output (UO). Organ dysfunction and vasopressor inotropic scores were also calculated. Median (IQR) age was 0.88 years (0, 3.75), and median weight was 6.62 kg (3.5, 13.7). Congenital heart disease was present in 70% (46/77) patients. Univentricular physiology was present in 25% (25/77) patients. None of the patients were in the immediate postoperative period. Median durations of AVP and CaCl were 2 days (1, 3) and 3 days (2, 6), respectively. Using Wilcoxon-signed rank test and Bonferroni correction, post hoc comparison showed that at 8 h post infusion, all systolic blood pressure (SBP) and diastolic blood pressure (DBP) results, and UO were greater than those 1 h prior to infusion. Median SBP increased from 79 mm Hg (71, 92) 1 h prior to 97 mm Hg (84, 107) 8 h post. Median DBP increased from 44 mm Hg (35, 52) 1 h prior to 54 mm Hg (44, 62) 8 h post. Heart rate showed a decrease between measurements 1 h prior to infusion and 8 h post, with median scores 146 (127, 162) and 136 (114, 150) beats per minute, respectively. Within first 8 h, median UO continuously increased from 6 mL/h. (0, 25) at 1 h post infusion to 20 mL/h. (2, 62) at 8 h post infusion. Median pediatric logarithmic organ dysfunction scores on days 4 through 7 post infusion were lower compared to day 1; median vasopressor inotropic scores on day 2 through 7 post infusion were lower compared to day 1. Serum lactate level, arterial pH, and base excess all showed favorable trend. Concurrent use of AVP and CaCl infusions may improve surrogates of cardiac output, and intensive care outcomes, and prevent organ dysfunction in children with AHF.

Clinical Associations of Early Dysnatremias in Critically Ill Neonates and Infants Undergoing Cardiac Surgery

Dysnatremias (DN) are common electrolyte disturbances in cardiac critical illness and are known risk factors for adverse outcomes in certain populations. Little information exists on DN in children with cardiac disease admitted to the cardiac intensive care unit (CICU) after undergoing cardiac surgery, either corrective or palliative. The aim was to determine the incidence and adverse outcomes associated with DN in neonates and infants undergoing cardiac surgery. Retrospective cohort and single center study performed at Children's Hospital Colorado from May 2013 to May 2014, in children under 1 year old admitted to the CICU after undergoing surgery for congenital or acquired cardiac disease. 183 subjects were analyzed.

EXCLUSIONS

subjects that demonstrated DN before surgery. Serum sodium levels were recorded for the first 72 h post-operatively. DN was present in 54% of the subjects (98/183): hypernatremia in 60 (33%), hyponatremia in 38 (21%). Multivariate analysis revealed that mild hypernatremia (146-150 mmol/dl) and moderate hypernatremia (151-155 mmol/dl) were associated with longer hospital length of stay (LOS, p < 0.05) and ventilation times (p < 0.05). No association was shown between mild/moderate hyponatremia (125-134 mmol/dl) with either outcome. Hours to DN were significantly lower in hypernatremic (median = 5.8 h) than hyponatremic (median = 43.8 h) patients (p < 0.001). Children younger than 30 days presented DN at an earlier stage than those 31 days-1 year old (median +2.2 vs. 17.3 h). No associations present between DN and the class of diuretic (loop vs. thiazide) administered, or the route of administration (intravenous bolus vs. constant infusion). Total median sodium bicarbonate administration was associated with hypernatremia, as was exposure to vasopressin within the first 72 h post-operatively. Dysnatremias are common in the early post-operative period in neonates and infants undergoing cardiac surgery. Mild to moderate hypernatremia, but not hyponatremia, is associated with longer LOS and longer ventilation time in infants undergoing cardiovascular surgery. Hypernatremia is also associated with younger infants, a higher surgical complexity, administration of bicarbonate and exposure to vasopressin. Diuretic type or interval timing of intravenous delivery did not demonstrate any effect. Prospective studies are needed in this population, in order to determine how DN, particularly hypernatremia, contributes to adverse outcomes, whether this association is independent of illness severity, and what may be safe treatments and interventions for these disorders.

Vasopressin improves hemodynamic status in infants with congenital diaphragmatic hernia

OBJECTIVE

To assess the ability of vasopressin to stabilize hemodynamics in infants with systemic hypotension secondary to congenital diaphragmatic hernia (CDH).

STUDY DESIGN

A retrospective chart review was performed to identify 13 patients with CDH treated with vasopressin for refractory hypotension to assess the effect of vasopressin on pulmonary and systemic hemodynamics and gas exchange in this setting. Data collected included demographics, respiratory support, inotropic agents, pulmonary and systemic hemodynamics, urine output, and serum and urine sodium levels during vasopressin therapy.

RESULTS

Vasopressin therapy increased mean arterial pressure and decreased pulmonary/systemic pressure ratio, heart rate, and fraction of inspired oxygen. In 6 of 13 patients, extracorporeal membrane oxygenation therapy was no longer indicated after treatment with vasopressin. Improvement in left ventricular function and oxygenation index after vasopressin initiation was associated with a decreased need for extracorporeal membrane oxygenation therapy. Prolonged vasopressin treatment was associated with hyponatremia, increased urine output, and increased urine sodium.

CONCLUSIONS

Vasopressin stabilized systemic hemodynamics without adverse effects on pulmonary hemodynamics in a subset of infants with CDH. Our results suggest a potential role for vasopressin therapy in patients with CDH with catecholamine-resistant refractory hypotension.