Central Arterial Line Placement for Pediatric Cardiac Surgery: A Single-Center Experience.

BACKGROUND: Peripheral arterial line placement is a common, low-risk procedure in pediatric patients undergoing cardiac surgery. Central arterial cannulation may be used when peripheral cannulation is not feasible. At present, there are limited data to guide central arterial-line site selection in pediatric patients. We aimed to (1) quantify the rate of complications associated with central arterial-line placement in pediatric patients undergoing cardiac surgery, (2) determine risk factors associated with central arterial-line complications, and (3) describe placement trends during the last decade. METHODS: This was a retrospective, single-center cohort study of pediatric patients who underwent intraoperative placement of an axillary or femoral arterial line for cardiac surgery between July 1, 2012 and June 30, 2022. The primary outcome studied was the incidence of complications, defined as vascular compromise, pulse loss, ultrasound-confirmed thrombus or flow abnormality, and/or positive blood cultures not attributable to another source. Patients' characteristics and perioperative factors were analyzed using univariate and multivariate analysis to examine the relationship between these factors and line-associated complications. RESULTS: A total of 1263 central arterial lines were analyzed-195 axillary arterial lines and 1068 femoral arterial lines. The overall incidences of vascular compromise and pulse loss from central arterial-line placement were 17.8% and 8.3%, respectively. Axillary lines had lower rates of vascular compromise (6.2% vs 19.9%, P < .001), pulse loss (2.1% vs 9.5%, P < .001), and ultrasound-confirmed thrombus of flow abnormalities (14.3% vs 81.1%, P = .001) than femoral lines. Complications were more common in neonates and infants. By multivariate logistic regression, femoral location (odds ratio [OR], 4.16, 95% confidence interval [CI], 1.97-8.78), presence of a genetic syndrome (OR, 1.68, 95% CI, 1.21-2.34), prematurity (OR, 1.48, 95% CI, 1.02-2.15), and anesthesia time (OR, 1.17 per hour, 95% CI, 1.07-1.27 per hour) were identified as independent risk factors for vascular compromise. Femoral location (OR, 7.43, 95% CI, 2.08-26.6), presence of a genetic syndrome (OR, 1.86, 95% CI, 1.18-2.93), prematurity (OR, 1.65, 95% CI, 1.02-2.67), and 22-G catheter size (OR, 3.26, 95% CI, 1.16-9.15) were identified as independent risk factors for pulse loss. CONCLUSIONS: Axillary arterial access is associated with a lower rate of complications in pediatric patients undergoing cardiac surgery as compared to femoral arterial access. Serious complications are rare and were limited to femoral arterial lines in this study.

The Evaluation of a Noninvasive Respiratory Volume Monitor in Mechanically Ventilated Neonates and Infants.

BACKGROUND: The respiratory volume monitor (RVM) (ExSpiron, Respiratory Motion Inc, Watertown, MA) uses thoracic impedance technology to noninvasively and continuously measure tidal volume (TV), respiratory rate (RR), and minute ventilation (MV). We aimed to validate the accuracy of the RVM to assess ventilation in neonates and infants by comparing it to spirometry. METHODS: We used the RVM and Respironics NM3 spirometer (Respironics NM3 Respiratory Profile Monitor, Philips Healthcare, Amsterdam, the Netherlands) to record simultaneous and continuous measurements of MV, TV, and RR. The RVM measurements, with and without external calibration, were compared to the Respironics NM3 spirometer using Bland-Altman analysis. The relative errors (Bland-Altman) between RVM and Respironics NM3 were calculated and used to compute individual patient bias, precision, and accuracy as the mean error, the standard deviation (SD) of the error, and the root mean square error. Bland-Altman limits of agreement (LoA) were computed, and equivalence tests were performed. RESULTS: Forty patients were studied to compare the RVM and Respironics NM3 measurements. The mean difference (ie, bias) for MV was 1.8% with 95% LoA, defined as mean ± 1.96 SD, in the range of -12.1% to 15.7%. Similarly, the mean difference (ie, bias) for TV and RR was 1.2% (95% LoA, -11.0% to 13.5%) and 0.6% (95% LoA, -3.7% to 5.0%), respectively. The mean measurement precision of the RVM relative to the Respironics NM3 for MV, TV, and RR was 10.8%, 8.9%, and 8.4%, respectively. The mean measurement accuracy for MV, TV, and RR across patients was 11.0%, 9.7%, and 7.1%, respectively. CONCLUSIONS: The data demonstrate that the RVM measures TV and MV in this cohort with an average relative error of 11% when using patient calibration and 16.9% without patient calibration. The average relative error of RR was 7.1%. The RVM provides accurate measurement of RR, TV, and MV in mechanically ventilated neonates and infants.

Twenty Years of Anesthetic and Perioperative Management of Patients With Tetralogy of Fallot With Absent Pulmonary Valve.

OBJECTIVE: Review the authors' institutional experience of the induction and perioperative airway management of children with tetralogy of Fallot with an absent pulmonary valve. DESIGN: Retrospective chart review. SETTING: Large academic children's hospital. PARTICIPANTS: Patients with the diagnosis of tetralogy of Fallot with absent pulmonary valve undergoing primary cardiac repair over a 20-year period. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Forty-four patients were identified with tetralogy of Fallot with an absent pulmonary valve from January 1995 through August 2014. Forty-two patients (95%) required surgery in their first year of life. Sixteen patients (36%) required mechanical ventilation preoperatively, including 11 neonates. Of the 28 patients not intubated preoperatively, only 1 (3.8%) exhibited minor airway obstruction following induction that was managed uneventfully. All intubations in the operating room were performed in the supine position. Five patients who were mechanically ventilated preoperatively in a lateral or prone position were supinated in the operating room without significant cardiopulmonary compromise. There were no patients who suffered cardiopulmonary arrest or required mechanical circulatory support. The median time to extubation was 2 days (range 1-13 days) in those patients who were not mechanically ventilated prior to their surgery. Ultimately, 5 patients required tracheostomy and 1 patient underwent lobectomy. Although, there was no mortality at 30 days, 4 children died within 1 year of their surgery. All the children who died had a genetic syndrome and required mechanical ventilation preoperatively. CONCLUSIONS: While there are theoretical concerns specific to the induction and airway management of tetralogy of Fallot with an absent pulmonary valve, there were no episodes of cardiorespiratory arrest or extracorporeal membrane oxygenation in the authors' series. Neonatal age at the time of surgery, preoperative need for mechanical ventilation, and concomitant genetic syndromes are risk factors for respiratory morbidity. Mortality in this study was low compared to historic reports, likely reflecting improvement in surgical technique and intensive care management.

Pausing With the Gauze: Inhibition of Temporary Pacemakers by Radiofrequency Scan During Cardiac Surgery.

BACKGROUND: Radiofrequency identification (RFID) detection systems are used to detect retained surgical sponges and may cause electromagnetic interference (EMI), altering intended function of cardiac pacing systems. Three pediatric patients requiring temporary pacing for postoperative atrioventricular block experienced transient inhibition of ventricular pacing during the use of RFID detection system. Bench testing was performed to evaluate the mechanism of pacemaker inhibition. METHODS: Impedance of temporary pacing wires was obtained using a pacing system analyzer. Temporary pacemakers (Medtronic 5388, Medtronic 5392, and Biotronik Reocor D) at nominal settings (VVI 120 bpm, output 10 mA) were attached at the ventricular terminal to temporary pacing wires and a resistor for sham impedance in physiologic range. An RFID detection system and wand (RF Assure, model 200) or mat was tested over wires. Induced current and voltages were recorded via an oscilloscope attached to lead terminals. Inhibition of pacing was determined for the following variables: distance from wires, sham impedance, and programmed sensitivity. RESULTS: In bench testing, the RFID system induced a stereotyped EMI signal in temporary pacing wires with peak root-mean-square voltage demonstrating an exponential decay relationship with increasing distance from pacing wires. Induced voltages overlapped with normal sensing range of temporary pacemakers, resulting in pacemaker inhibition at nominal settings (ventricular sensitivity 2.0 mV, distance from wand <23 cm). Increasing height, decreasing device sensitivity, or increasing sham impedance (at fixed sensitivity) attenuated EMI and inhibition for all 3 temporary pacemakers used and with the automated RFID detection mat in place of the wand. Programming pacemakers asynchronously prevented inhibition. CONCLUSIONS: Normal operation of RFID detection systems may cause inhibition of temporary pacing systems consistent with oversensing from EMI. Precaution should be taken, including considering pacing asynchronously to avoid effects of inhibition.

Propofol compared with isoflurane inhibits mitochondrial metabolism in immature swine cerebral cortex.

Anesthetics used in infants and children are implicated in the development of neurocognitive disorders. Although propofol induces neuroapoptosis in developing brain, the underlying mechanisms require elucidation and may have an energetic basis. We studied substrate utilization in immature swine anesthetized with either propofol or isoflurane for 4 hours. Piglets were infused with 13-Carbon-labeled glucose and leucine in the common carotid artery to assess citric acid cycle (CAC) metabolism in the parietal cortex. The anesthetics produced similar systemic hemodynamics and cerebral oxygen saturation by near-infrared spectroscopy. Compared with isoflurane, propofol depleted ATP and glycogen stores. Propofol decreased pools of the CAC intermediates, citrate, and α-ketoglutarate, while markedly increasing succinate along with decreasing mitochondrial complex II activity. Propofol also inhibited acetyl-CoA entry into the CAC through pyruvate dehydrogenase, while promoting glycolytic flux with marked lactate accumulation. Although oxygen supply appeared similar between the anesthetic groups, propofol yielded a metabolic phenotype that resembled a hypoxic state. Propofol impairs substrate flux through the CAC in the immature cerebral cortex. These impairments occurred without systemic metabolic perturbations that typically accompany propofol infusion syndrome. These metabolic abnormalities may have a role in the neurotoxity observed with propofol in the vulnerable immature brain.