Disease Markers

Review Article

Ventilatory Efficiency in Children and Adolescents: A Systematic Review

Table 3

Summary of the selected studies from PEDro, MedLine, and PubMed.


Study	Type of study	Objective	Sample	Conclusion

[9]	Clinical trial and prospective	To provide reference values for cardiorespiratory ability, respiratory function, and hemodynamic responses during and after the maximal exercise test on stationary bicycles in children.	140 children (69 girls), ages 9–11.	The boys’ indicators of cardiorespiratory capability surpassed the girls’. There was no difference in the VE/VCO₂ index between the sexes.

[8]	Clinical trial and prospective	To use parameters to develop a multivariate model for predicting mortality in adolescents with CF.	127 adolescents with CF (mean age = 12.7 ± 0.9).	The joint evaluation of BMI, FEV₁%, and VE/VO₂ is a strong predictor of CF adolescent mortality.

[34]	Clinical trial	To create prediction equations for the CPT variables based solely on patients with Fontan circulation.	411 patients were submitted to the CPT; 166 in the maximal exercise stress test.	The VE/VCO₂ and VE/VO₂ indices at the anaerobic threshold had an inferior outcome in the validation cohort. Six from the eight prediction equations for the CPT variables proved valuable and were validated.

[11]	Clinical trial and prospective	To evaluate the exercise capacity in cardiac patients and compare the results between the two corrective surgical techniques.	101 patients submitted to the CPT.	VE/VCO₂ was 127% ± 30% from the predicted value. Results showed a reduced exercise capacity in patients with Fontan correction.

[12]	Clinical trial and controlled	To evaluate the correlation between ventilatory efficiency and the functional capacity in pediatric patients with PH.	76 children and young adults with PH were submitted to 258 cardiopulmonary exercise tests.	The VE/VCO₂ index was higher in PH patients, in comparison to the control group. The index was the highest in 12 patients with the worst prognosis (nine deceased, three pulmonary transplants).

[13]	Clinical trial, multicentric and prospective	To evaluate the ventricular function and metabolic effort test between sexes.	272 patients (158 boys (mean age = 14.3 ± 3.3)) with TF.	Women had a more inferior performance than men regarding the systolic function of the right ventricle, evaluated with cardiac magnetic resonance and exercise capacity, in addition to presenting a higher VE/VCO₂ index.

[14]	Clinical trial and retrospective	To supply reference data for the CPT variables in children and adolescents.	76 healthy children and adolescents who underwent the PCT test using the modified Bruce protocol.	The VE/VCO₂ index did not differ between boys and girls. In the group aged from 15–19 years, the boys presented higher values of VO₂peak and lower values of the VE/VCO₂ index than the girls.

[35]	Clinical trial and prospective	To evaluate the association of the VO₂peak <50% of the predicted value during the CPT in cardiac children with death risk or deterioration of cardiac function.	50 children (24 girls (mean age = 15, range = 13–17)), 18 with a single ventricle in palliative care.	VE/VCO₂ ≥ 34 was associated with children with biventricular circulation but not with children with a single ventricle in palliative care.

[24]	Controlled	To evaluate the ventilatory dynamics in obese and nonobese children.	73 overweight children were compared using parameters of age, sex, and height.	The VE/VCO₂ index was similar between groups.

[36]	Clinical trial and cross-sectional	To investigate the efficiency of oxygen absorption in children with CHD.	31 adolescents with CHD (16 with repaired Fontan and 15 with TF) underwent the CPT.	Ventilatory efficiency may be a valid parameter, regardless of the cardiorespiratory capability of children with coronary disease.

[37]	Clinical trial and cross-sectional	To verify if children present different responses to the evaluated cardiorespiratory and metabolic parameters during the maximal progressive exercise test when compared to adults.	25 healthy children (15 males, 10 females) (mean age 10.2 ± 0.2) and 20 healthy adults (11 males, 9 females) (mean age = 27.5 ± 0.4).	During the CPT, at the ventilatory anaerobic threshold, the HR, VO₂, RF, VCO₂, VD/VT, VE/VO₂, VE/VCO₂, and PETO₂ responses were higher in children when compared to adults.

[38]	Clinical trial, controlled and randomized	To verify in obese children if (1) ventilatory efficiency is diminished during progressive exercise, (2) loss of weight through diet improves ventilatory efficiency, and (3) diet associated with exercise training improves ventilatory efficiency.	38 obese children. Ten healthy children were included as a control group. All children underwent CPT.	Ventilatory efficiency was lower in obese children who presented weight loss through progressive exercise.

[29]	Cross-sectional	To determine if, in patients with corrected TF, there was improvement in the poor pulmonary blood flow distribution, after a surgical procedure, during exercise.	17 patients with corrected TF and residual stenosis of the pulmonary artery who were forwarded to a balloon angioplasty.	The patients with the balloon angioplasty presented a better VO₂peak and more efficient gas exchange during exercise.

[15]	Clinical trial and randomized	To investigate the effect of an eight-week exercise training course on the ventilatory threshold and ventilatory efficiency in overweight children.	20 overweight children underwent the progressive exercise test. They were split randomly into eight weeks of cyclism or a control group.	Aerobic exercise training may help to reverse the loss of cardiopulmonary function observed throughout time in overweight children.

[25]	Controlled	To verify ventilatory efficiency and the effort perception in obese and nonobese children submitted to a standard exercise load.	60 children (aged 6–17) were divided into two groups: 30 obese and 30 healthy individuals.	The VE/VCO₂ index did not differ between groups. In the studied population, the metabolic cost during exercise was higher in the obese group when compared to the control individuals.

[16]	Cross-sectional	To verify the differences in the ventilatory response to exercise in children and preadolescent individuals.	100 children divided into two groups: 10 years old and 13 years old.	There are differences in age and sex, in some aspects, of the ventilatory responses in pediatric subjects.

[19]	Controlled	To evaluate intra- and interrater reliability and the validity of the ventilatory threshold parameter in children.	35 premature children aged 6–12 years, and 20 term born controls.	The TV was considered the valid parameter for establishing aerobic capacity.

[32]	Cross-sectional	To investigate the relation between age and respiratory control in pediatrics.	80 children aged 6.4–17.6 years (42 males and 38 females).	Younger children, while eliminating CO₂ and regulating PaCO₂, presented less tachypnea during exercise when compared to older children.

[31]	Controlled	To document the ventilatory response to exercise in patients with exercise-induced bronchial obstruction.	11 children with bronchial obstructions.	Patients with a bronchial obstruction develop bronchoconstriction during exercise.

[17]	Cross-sectional and controlled	To determine the relation between the PCO₂ and CO₂ receptors and the respiratory response during exercise in healthy children and children with CF.	16 healthy children and 16 children with CF in phase 1 and 28 healthy children and 23 children with CF in phase 2.	The younger children ventilate more during exercise than the older children because they regulate the PaCO₂ at a lower level. The hypercapnic ventilatory response may be reduced in the presence of airway obstructions, being that a low hypercapnic ventilatory response may permit an exercise-induced hypercapnia in some patients with CF or advanced pulmonary disease.

[18]	Controlled	To evaluate the MV during exercise in a cycle ergometer in children with central hypoventilation syndrome compared to a control group.	6 children with CCHS and 6 healthy children.	The passive movement of the legs in pedaling increased the MV in both groups. The passive movement of the legs normalized the PetCO₂ in patients with hypoventilation syndrome.

[30]	Clinical trial and controlled	To evaluate the effects of aerobic training on adolescents and young adults with Down syndrome.	14 individuals with Down syndrome (mean age = 17.7).	Even though the training program did not improve aerobic capacity, it improved walking capacity.

[28]	Cross-sectional and controlled	To test, through exercise, the poor perfusion after intracardiac repair of TF.	13 children aged from 8–18 years, clinically stable (Class I) with 7–14 years post-op of the intracardiac repair of the TF, and 16 children in the control group.	The clinically stable children may present abnormalities in gas exchange, which is compatible with the slightly poor pulmonary perfusion expected 7–14 years after the surgical repair of TF.

[39]	Controlled	To evaluate the increase in aerobic metabolism in SCD patients.	34 patients with SCD, and 16 control individuals.	Children with SCD have an increased ventilatory response during exercise caused, partially, by the physiological increase of dead space and low hemoglobin. The increase in pulmonary dead space may be the result of sickled cells, which affect the capillary perfusion of the ventilated alveoli.

[33]	Cross-sectional	To establish normative data for untrained children through the James protocol in stationary bicycles.	151 North American children aged from 7–12 years.	The data may be used in the evaluations of preadolescents in North America.

[20]	Cross-sectional	To evaluate the pulmonary ventilation and gas exchange in anesthetized children with halothane, enflurane, and isoflurane.	24 children who were submitted to surgical procedures.	Although the MV was lower with the enflurane, the ventilatory efficiency was similar between the anesthetics.

[22]	Cross-sectional	To investigate the ventilatory efficiency during the use of halothane.	18 babies and children with congenital heart disease divided into two groups (1) hyperperfusion and shunt from left to right and (2) hypoperfusion and shunt from right to left.	The VE/VCO₂ and VD/VT were higher in children with diminished pulmonary blood flow, indicating a less efficient gas exchange in children with shunt from right to left.

CO₂: carbon dioxide; CCD: congenital cardiac disease; RF: respiratory frequency; PaCO₂: carbon dioxide partial pressure; PetCO₂: end-tidal carbon dioxide pressure; MV: minute ventilation; VCO₂: partial pressure of CO₂ in arterial blood; VD/VT: dead space/tidal volume ratio; VE/VCO₂: ventilatory efficiency index; VE/VO₂: ventilatory equivalent for oxygen; TV: tidal volume; HR: heart rate; BMI: body mass index; CF: cystic fibrosis; PH: pulmonary hypertension; CPT: cardiopulmonary test.