The Accuracy of Noninvasive Peripheral Pulse Oximetry After Palliative Cardiac Surgery in Patients With Cyanotic Congenital Heart Disease.

BACKGROUND: Children with cyanotic congenital heart disease (CCHD) live with oxyhemoglobin saturations that are typically expressed as percentages in the range of 70s and 80s. Peripheral pulse oximetry (measurement of SpO2) performs poorly in this range and yet is widely used to inform clinical decisions in these patients. The reference standard is co-oximetry of arterial samples (SaO2). METHODS: In this study, 515 paired measurements of SpO2 and SaO2 were taken from 19 children who had undergone palliative cardiac surgery. RESULTS: SpO2 (Masimo SET LNCS Neo pulse oximeter) overestimated oxyhemoglobin saturation in 82% of measurements (mean 4.6% ± 6.6%). There was a strong negative correlation between mean bias and SaO2 ( r = -.96, P = .002, 95% confidence interval: -0.99 to -0.68). CONCLUSION: The results raise a concern that critical hypoxemia may go undetected and untreated if pulse oximetry is relied upon as the primary means of assessing oxyhemoglobin saturation in children with CCHD. Strong preference must be given to co-oximetry of arterial samples.

Accuracy of the Masimo SET® LNCS neo peripheral pulse oximeter in cyanotic congenital heart disease.

UNLABELLED: Introduction Non-invasive peripheral pulse oximeters are routinely used to measure oxyhaemoglobin saturation (SpO2) in cyanotic congenital heart disease. These probes are calibrated in healthy adult volunteers between arterial saturations of ~75 and 100%, using the gold standard of co-oximetry on arterial blood samples. There are little data to attest their accuracy in cyanotic congenital heart disease. Aims We aimed to assess the accuracy of a commonly used probe in children with cyanotic congenital heart disease. METHODS: Children with cyanotic congenital heart disease admitted to the Paediatric Intensive Care Unit with an arterial line in situ were included to our study. Prospective simultaneous recordings of SpO2, measured by the Masimo SET® LNCS Neo peripheral probe, and co-oximeter saturations (SaO2) measured by arterial blood gas analysis were recorded. RESULTS: A total of 527 paired measurements of SpO2 and SaO2 (using an ABL800 FLEX analyser) in 25 children were obtained. The mean bias of the pulse oximeter for all SaO2 readings was +4.7±13.8%. The wide standard deviation indicates poor precision. This mean bias increased to +7.0±13.7% at SaO2 recordings <75%. The accuracy root mean square of the recordings was 3.30% across all saturation levels, and this increased to 4.98% at SaO2 <75%. CONCLUSIONS: The performance of the Masimo SET® LNCS Neo pulse oximeter is poor when arterial oxyhaemoglobin saturations are below 75%. It tends to overestimate saturations in children with cyanotic congenital heart disease. This may have serious implications for clinical decisions.

Gas induction for pyloromyotomy.

BACKGROUND: Infants with pyloric stenosis are considered to be at high risk of aspiration on induction of anesthesia. Traditionally, texts have recommended classic rapid sequence induction (RSI) or awake intubation (AI). AI has generally fallen out of favor, while the components of RSI have become increasingly controversial. Infants are at high risk of hypoxemia if ventilation is not maintained while waiting for neuromuscular blockade to establish. The efficacy of cricoid pressure (CP) to prevent aspiration has not been proven. It can impair visualization of the glottis and make intubation difficult. It is debatable whether any RSI technique is needed for pyloromyotomy. A recent review of 235 infants reported no aspiration events. These children were anesthetized with a variety of techniques, including RSI, gas induction, and AI. In our institution, we teach a gaseous induction. The nasogastric tube is used to empty the stomach and anesthesia is induced with sevoflurane. A nondepolarizing muscle relaxant is administered and ventilation maintained until neuromuscular blockade is established and intubating conditions are optimal. We report our experience of this technique. METHOD: A retrospective medical notes review of all patients undergoing pyloromyotomy between 2005 and 2012. RESULTS: There were 269 patients (84.4% male, mean weight 3.74 kg ± 0.74). Two hundred and fifty-two (93.7%) received gas inductions and 17 (6.3%) intravenous (IV) inductions. Two children received an RSI. No patient-specific factors were identified to explain operator choice in those receiving IV inductions. There were no recorded aspiration events. CONCLUSION: Gas induction can be considered for children undergoing pyloromyotomy.