# Carbon Dioxide and Hemoglobin at Presentation with Hypertrophic Pyloric Stenosis—Are They Relevant? Cohort Study and Current Opinions

## TL;DR

This study explores how hemoglobin and carbon dioxide levels relate in infants with pyloric stenosis, finding a link that may affect respiratory issues.

## Contribution

The study introduces a new perspective using the Stewart model to explain the complex acid-base dynamics in pyloric stenosis.

## Key findings

- Hypercapnia was observed in many infants with signs of hemoconcentration.
- A positive correlation was found between hemoglobin and pCO2 levels.
- Lactate levels were not affected by elevated pCO2.

## Abstract

Background

In infantile hypertrophic pyloric stenosis, recurrent vomiting of gastric contents leads to metabolic alkalosis, which is compensated for by an increase in carbon dioxide.Carbon dioxide acts as a respiratory stimulus a priori, but at high concentrations it may have a depressant effect on respiration.The role of blood carbon dioxide tension (pCO2) in the development of respiratory problems remains unclear.

In infantile hypertrophic pyloric stenosis, recurrent vomiting of gastric contents leads to metabolic alkalosis, which is compensated for by an increase in carbon dioxide.

Carbon dioxide acts as a respiratory stimulus a priori, but at high concentrations it may have a depressant effect on respiration.

The role of blood carbon dioxide tension (pCO2) in the development of respiratory problems remains unclear.

Material and Methods

A retrospective monoinstitutional cohort study was conducted on 105 infants.The following parameters were recorded on admission: biometrics, acid/base status, hemoglobin, lactate and sodium.The present study aims to determine the interaction between hemoglobin and the other acid/base components on pCO2.

A retrospective monoinstitutional cohort study was conducted on 105 infants.

The following parameters were recorded on admission: biometrics, acid/base status, hemoglobin, lactate and sodium.

The present study aims to determine the interaction between hemoglobin and the other acid/base components on pCO2.

Results

Hypercapnia was observed in a relevant number of children.Infants exhibiting hypercapnia have been observed to demonstrate signs of hemoconcentration.A positive correlation was identified between the concentration of hemoglobin and the partial pressure of carbon dioxide.The lactate level was not affected by the elevated partial pressure of carbon dioxide (pCO2).

Hypercapnia was observed in a relevant number of children.

Infants exhibiting hypercapnia have been observed to demonstrate signs of hemoconcentration.

A positive correlation was identified between the concentration of hemoglobin and the partial pressure of carbon dioxide.

The lactate level was not affected by the elevated partial pressure of carbon dioxide (pCO2).

Conclusions

There is a dependence of pCO2 on hemoglobin.An increase in carbon dioxide cannot easily be attributed to reduced carbon dioxide transport function due to hemoglobin deficiency.The physico-chemical Stewart model is a theoretical framework that can be utilized to elucidate the complex pathophysiology of gastric alkalosis in IHPS. This approach offers a novel perspective on the investigation of this condition.

There is a dependence of pCO2 on hemoglobin.

An increase in carbon dioxide cannot easily be attributed to reduced carbon dioxide transport function due to hemoglobin deficiency.

The physico-chemical Stewart model is a theoretical framework that can be utilized to elucidate the complex pathophysiology of gastric alkalosis in IHPS. This approach offers a novel perspective on the investigation of this condition.

Background: Recurrent vomiting in infantile hypertrophic pyloric stenosis (IHPS) leads to metabolic alkalosis and a respiratory-driven compensatory hypercapnia. Alkalosis has been identified as the main causal factor for respiratory depression on admission. The value of contribution of hemoglobin and carbon dioxide partial pressure to this phenomenon will be evaluated. Materials and Methods: A retrospective cohort study was conducted on 105 infants with IHPS. The acid/base status, including levels of hemoglobin and lactate, were recorded. Statistical comparisons, correlation analysis, linear regression and multivariate regression analysis were applied. Results: Hypercapnia was associated with hemoconcentration. We found a positive correlation was found between pCO2 and hemoglobin (p = 0.042). The multivariate linear regression analysis showed that pCO2 is dependent on hemoglobin (p = 0.002). Lactate, which is used as a marker for anaerobic glycolysis, showed no systematic correlation with pCO2. Conclusions: An increase in carbon dioxide cannot easily be attributed to a reduced transport function of carbon dioxide due to hemoglobin deficiency. Further investigation is needed to determine the extent to which low hemoglobin levels and increased pCO2 interact with hemoconcentration to contribute to respiratory problems.