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.

Bilateral pulmonary artery banding in higher risk neonates with hypoplastic left heart syndrome.

Objectives: Limited data on performing bilateral pulmonary artery banding (BPAB) before stage 1 Norwood procedure suggest that some patients may benefit through the postponement of the major cardiopulmonary bypass procedure. The objective of this study was to evaluate the effectiveness of BPAB in the surgical management of high-risk patients with hypoplastic left heart syndrome (HLHS). Methods: A retrospective review of all high-risk neonates with HLHS who underwent BPAB at our institution was performed. No patients, including those with intact or highly restrictive atrial septum (IAS), were excluded. Results: Between October 2015 and April 2021, 49 neonates with HLHS (including 6 with IAS) underwent BPAB, 40 of whom progressed to the Norwood procedure. Risk factors for not progressing to the Norwood procedure after BPAP include low birth weight (P = .043), the presence of multiple extracardiac anomalies (P = .005), and the presence of genetic disorders (P = .028). Operative mortality was 7.5% (3/40). IAS was associated with operative mortality (P = .022). Conclusions: The strategy of BPAB prestage 1 Norwood procedure was successful in identifying at-risk patients and improving Norwood survival. Although not all patients will need this hybrid approach, a significant number can be expected to benefit from this tactic. These results support the need for a substantial hybrid strategy, in addition to a primary stage 1 Norwood surgical strategy, in the management of HLHS.

Effect of Nitric Oxide Delivery Device on Tidal Volume Accuracy During Mechanical Ventilation at Small Tidal Volumes.

BACKGROUND: Inhaled nitric oxide (INO) is used in infants as a therapy for elevated pulmonary vascular resistance. When INO is delivered at low tidal volumes, displayed inspiratory and expiratory volumes vary widely. We hypothesize that volume is removed by the sampling line during the ventilation cycle, and this results in a net volume loss at low tidal volumes. This study aimed to measure the volumes delivered and to assess the accuracy of displayed ventilator values using a test lung. METHODS: A test lung was connected to a ventilator and an INO delivery system. All tests were performed with stable mode settings across volumes of 18, 30, 42, and 60 mL. Flow measured with a pneumotachometer attached between the test lung and the circuit assessed the percent error between inspiratory and expiratory volumes measured by the pneumotachometer measured and displayed on the ventilator under various INO/sample line conditions to determine where and how much volume was being displaced. RESULTS: Displayed and measured inspiratory volumes had small variations between the INO/sample line conditions and baseline. However, expiratory volumes, with the sample line connected, exhibited large percent error values that increased (-14, -20, -27, and -34) as tidal volume decreased (60, 42, 30, and 18 mL) and error was significantly larger compared to baseline in all tidal volumes (P < .01) with and without INO delivery. CONCLUSIONS: We concluded that inspiratory volumes were not affected by INO delivery, but additional removal of volume in the expiratory phase of the breath cycle by the sampling line results in a large error in the displayed expiratory volume.

Sleep and mechanical ventilation in the intensive care unit.

Sleep is essential to a patient's well-being. The importance of sleep is highlighted by the adverse effects in the wake of its absence both physically and mentally. Sleep is difficult to achieve in the intensive care unit due to noise, patient care activities, illness, and mechanical ventilation. Activities related to mechanical ventilation such as suctioning, discomfort of the essential tremor, alarms, treatments and sedation effects can all alter sleep architecture. However, mechanical ventilation itself especially as it relates to asynchrony may also play a larger role than previously thought. This paper aims to review sleep in the intensive care unit and the relationship of mechanical ventilation.