How to best induce anesthesia in infants with pyloric stenosis?

Perioperative Hypoxemia and Postoperative Respiratory Events in Infants with Hypertrophic Pyloric Stenosis

BACKGROUND

 Normalization of metabolic alkalosis is an important pillar in the treatment of infantile hypertrophic pyloric stenosis (IHPS) because uncorrected metabolic alkalosis may lead to perioperative respiratory events. However, the evidence on the incidence of respiratory events is limited. We aimed to study the incidence of peroperative hypoxemia and postoperative respiratory events in infants undergoing pyloromyotomy and the potential role of metabolic alkalosis.

MATERIALS AND METHODS

 We retrospectively reviewed all patients undergoing pyloromyotomy between 2007 and 2017. All infants received intravenous fluids preoperatively to correct metabolic abnormalities close to normal. We assessed the incidence of perioperative hypoxemia (defined as oxygen saturation [SpO2] < 90% for > 1min) and postoperative respiratory events. Additionally, the incidence of difficult intubations was evaluated. We performed a multivariate logistic regression analysis to evaluate the association between admission or preoperative serum pH values, bicarbonate or chloride, and peri- and postoperative hypoxemia or respiratory events.

RESULTS

 Of 406 included infants, 208 (51%) developed 1 or more episodes of hypoxemia during the perioperative period, of whom 130 (32%) experienced it during induction, 43 (11%) intraoperatively, and 112 (28%) during emergence. About 7.5% of the infants had a difficult intubation and 17 required more than 3 attempts by a pediatric anesthesiologist. Three patients developed respiratory insufficiency and 95 postoperative respiratory events were noticed. We did not find a clinically meaningful association between laboratory values reflecting metabolic alkalosis and respiratory events.

CONCLUSIONS

 IHPS frequently leads to peri- and postoperative hypoxemia or respiratory events and high incidence of difficult tracheal intubations. Preoperative pH, bicarbonate, and chloride were bad predictors of respiratory events.

Risk of Hypoxemia by Induction Technique Among Infants and Neonates Undergoing Pyloromyotomy

BACKGROUND

In patients presenting for pyloromyotomy, most practitioners prioritize rapid securement of the airway due to concern for aspiration. However, there is a lack of consensus and limited evidence on the choice between rapid sequence induction (RSI) and modified RSI (mRSI).

METHODS

The medical records of all patients presenting for pyloromyotomy from May 2012 to December 2018 were reviewed. The risk of hypoxemia (peripheral oxygen saturation [Spo2], <90%) during induction was compared between RSI and mRSI cohorts for all patients identified as well as in the neonate subgroup by univariate and multivariable logistic regression analysis. Complications (aspiration, intensive care unit admission, bradycardia, postoperative stridor, and hypotension) and initial intubation success for both cohorts were also compared.

RESULTS

A total of 296 patients were identified: 181 in the RSI and 115 in the mRSI cohorts. RSI was associated with significantly higher rates of hypoxemia than mRSI (RSI, 30% [23%-37%]; mRSI, 17% [10%-24%]; P = .016). In multivariable logistic regression analysis of all patients, the adjusted odds ratio (OR) of hypoxemia for RSI versus mRSI was 2.8 (95% confidence interval [CI], 1.5-5.3; P = .003) and the OR of hypoxemia for multiple versus a single intubation attempt was 11.4 (95% CI, 5.8-22.5; P < .001). In multivariable logistic regression analysis of neonatal subgroup, the OR of hypoxemia for RSI versus mRSI was 6.5 (95% CI, 2.0-22.2; P < .001) and the OR of hypoxemia for multiple intubation versus single intubation attempts was 18.1 (95% CI, 4.7-40; P < .001). There were no induction-related complications in either the RSI and mRSI cohorts, and the initial intubation success rate was identical for both cohorts (78%).

CONCLUSIONS

In infants presenting for pyloromyotomy, anesthetic induction with mRSI compared with RSI was associated with significantly less hypoxemia without an observed increase in aspiration events. In addition, the need for multiple intubation attempts was a strong predictor of hypoxemia. The increased risk of hypoxemia associated with RSI and multiple intubation attempts was even more pronounced in neonatal patients.

Ultrasound assessment of the gastric contents for the guidance of the anaesthetic strategy in infants with hypertrophic pyloric stenosis: a prospective cohort study

BACKGROUND

Evacuation of gastric content through a nasogastric tube, followed by rapid sequence induction, is usually recommended in infants undergoing pyloromyotomy. However, rapid sequence induction may be challenging, and is therefore controversial. Some anaesthetists regularly perform classical non-rapid induction technique, after blind aspiration of the gastric contents, although this aspiration may have been incomplete. This prospective observational study aimed to assess whether the ultrasound monitoring of the aspiration of the stomach contents, may be useful to appropriately guide the choice of the anaesthetic induction technique, in infants undergoing pyloromyotomy.

METHODS

Infants undergoing pyloromyotomy were consecutively included. Ultrasound assessment of the antrum was performed before and after the aspiration of the gastric contents through a 10 French gastric tube. The stomach was defined as empty when no content was seen in both supine and right lateral positions. The correlation between antral area and the aspirated gastric volume was also tested.

RESULTS

We analysed 34 infants. Ultrasound examination of the antrum failed in three infants. The stomach was empty in 30/34 infants (nine before aspiration, 21 after aspiration), allowing to perform a non-rapid induction technique in 88.2% of the infants. There was a significant correlation between antral area measured in right lateral decubitus and the aspirated gastric volume.

CONCLUSIONS

Our results suggest that the qualitative ultrasound assessment of the antral content may be a simple and useful point-of-care tool, for the choice of the most appropriate anaesthetic technique for pyloromyotomy according to the estimated risk of pulmonary aspiration of gastric contents.