Effects of bronchial blockers on gas exchange in infants with one-lung ventilation: a single-institutional experience of 22 cases

Point-of-care ultrasound to confirm the position of bronchial blockers in children

PURPOSE

We described the accuracy of ultrasound in determining the position of bronchial blockers (BBs) in children underwent thoracoscopic surgery.

METHODS

We enrolled 52 children with ASA grade I-III who received thoracoscopic surgery with placement of BBs. Point-of-care ultrasound was performed according to the BLUE protocol. The ultrasound-guided lung sliding sign and curtain sign were used to assess the position of BBs. The accuracy of ultrasound in evaluating the position of BBs, as well as the accuracy and operating time of sliding sign and curtain sign at each examination point were recorded and compared.

RESULTS

The accuracy of ultrasound in evaluating the position of BBs was 88% (46/52, 95% CI 0.69-0.97). When using the curtain sign to assess the position of BBs, the accuracy was 90% (94/104, 95% CI 0.78-0.96), which was significantly higher than when using the sliding sign (65% (136/208), 95% CI 0.55-0.74) (p = 0.002). The accuracy of curtain sign at the left mid-axillary line-diaphragm and the right mid-axillary line-diaphragm was respectively 96% (50/52, 95% CI 0.80-0.99) and 84% (44/52, 95% CI 0.65-0.95), which were higher than that of sliding sign at upper blue points and lower blue points. There was no significant difference in the operating time between two ultrasound signs (the curtain sign, 13.4 ± 8.2 s vs. the lung sliding sign, 16.2 ± 10.0 s, p = 0.065).

CONCLUSION

Point-of-care ultrasound can effectively assess the position of BBs. The accuracy of using the curtain sign at the mid-axillary line-diaphragm is higher than that of using the lung sliding sign at the anterior chest wall.

Comparison between pressure-controlled ventilation with volume-guaranteed mode and volume-controlled mode in one-lung ventilation in infants undergoing video-assisted thoracoscopic surgery

BACKGROUND

The appropriate ventilation mode for one-lung ventilation (OLV) in infants undergoing video-assisted thoracoscopic surgery (VATS) remains controversial. Here we investigated the effect of ventilatory mode "pressure-controlled ventilation-volume guaranteed" (PCV-VG) on the airway pressures and oxygenation parameters by comparing it with volume-controlled ventilation (VCV).

METHODS

We retrospectively analyzed the clinical data of infants aged 2 to 12 months who underwent extratracheal bronchial blockage for OLV in our center between January 2017 and August 2020. The infants were divided into two groups according to the OLV pattern: group G (n=30, receiving PCV-VG) and group V (n=28, receiving VCV). Mean arterial pressure (MAP), heart rate (HR), maximum inspiratory pressure (P_peak), mean airway pressure (P_mean), dynamic compliance (Cdyn), partial arterial pressure of oxygen (PaO₂) was measured and compared between these two groups 10 min before OLV (T1), 30 min after the onset of OLV (T2) and 15 min after OLV (T3). The possible occurrence of hypoxemia and hypotension during OLV was monitored.

RESULTS

Compared to group V, group G had significantly higher PaO₂and C_dyn (both P<0.05) and significantly lower P_peak and P_mean (both P<0.05) in T2. However, all indicators did not show significant differences between these two groups at T1 and T3 (all P>0.05). The incidence of hypoxemia was significantly higher in group V than in group G (P<0.05), while the difference in the incidence of hypotension was not statistically significant (P>0.05).

CONCLUSIONS

Mechanical ventilation using the PCV-VG mode is possible in infants when performing OLV during VATS. Compared to VCV, PCV-VG can offer lower P_peak and P_mean, improve lung compliance, and achieve better oxygenation.