Cerebral oxygenation and desaturations in preterm infants - a longitudinal data analysis

Fluctuations in Oxygen Saturation during Synchronized Nasal Intermittent Positive Pressure Ventilation and Nasal High-Frequency Oscillatory Ventilation in Very Low Birth Weight Infants: A Randomized Crossover Trial

BACKGROUND

Very low birth weight (VLBW) infants on noninvasive ventilation (NIV) experience frequent fluctuations in oxygen saturation (SpO2) that are associated with an increased risk for mortality and severe morbidities.

METHODS

In this randomized crossover trial, VLBW infants (n = 22) born 22+3 to 28+0 weeks on NIV with supplemental oxygen were allocated on two consecutive days in random order to synchronized nasal intermittent positive pressure ventilation (sNIPPV) and nasal high-frequency oscillatory ventilation (nHFOV) for 8 h. nHFOV and sNIPPV were set to equivalent mean airway pressure and transcutaneous pCO2. Primary outcome was the time spent within the SpO2 target (88-95%).

RESULTS

During sNIPPV, VLBW infants spent significantly more time within the SpO2 target (59.9%) than during nHFOV (54.6%). The proportion of time spent in hypoxemia (22.3% vs. 27.1%) and the mean fraction of supplemental oxygen (FiO2) (29.4% vs. 32.8%) were significantly reduced during sNIPPV, while the respiratory rate (50.1 vs. 42.6) was significantly higher. Mean SpO2, SpO2 above the target, number of prolonged (>1 min) and severe (SpO2 <80%) hypoxemic episodes, parameters of cerebral tissue oxygenation using NIRS, number of FiO2 adjustments, heart rate, number of bradycardias, abdominal distension and transcutaneous pCO2 did not differ between both interventions.

CONCLUSIONS

In VLBW infants with frequent fluctuations in SpO2, sNIPPV is more efficient than nHFOV to retain the SpO2 target and to reduce FiO2 exposure. These results demand more detailed investigations into cumulative oxygen toxicities during different modes of NIV over the weaning period, particularly with regard to consequences for long-term outcomes.

Changes in cerebral tissue oxygenation and fractional oxygen extraction with gestational age and postnatal maturation in preterm infants

OBJECTIVE

This study examined the correlation of cerebral tissue oxygen saturation (SctO₂) and cerebral tissue fractional oxygen extraction (cFTOE) with gestational age (GA) and postnatal age over the first 28 days of life.

STUDY DESIGN

Preterm infants with birth weight (BW) <1500 g were monitored with near-infrared spectroscopy (NIRS) during the first 28 days of life. SctO₂ and cFTOE measurements were analyzed using a linear mixed model.

RESULTS

A total of 70 preterm infants were included. Mean SctO₂ decreased with increasing GA; SctO₂ was 76.4% and 74.6% in the first 24 h for infants 24 and 28-week GA, respectively. For infants born at 24 and 28 it decreased to 52.9% and 58.4% at 28 days of life, respectively. cFTOE increased with increasing GA and postnatal age.

CONCLUSIONS

There is an inverse relationship between SctO₂ and gestational age and postnatal age but a direct relationship between cFTOE with GA and postnatal age.

Effects of spinal anesthesia and sedation with dexmedetomidine or propofol on cerebral regional oxygen saturation and systemic oxygenation a period after spinal injection

PURPOSE

To evaluate changes in cerebral regional oxygen saturation (rSO₂) after spinal anesthesia and compare the changes in rSO₂ and systemic oxygenation between dexmedetomidine sedation and propofol sedation.

METHODS

Thirty-six patients scheduled to undergo transurethral surgery under spinal anesthesia were randomly assigned to the dexmedetomidine (n = 18) and propofol groups (n = 18). We used near-infrared spectroscopy sensors to measure rSO₂, and obtained data from each side were averaged. After oxygen insufflation, baseline measurements of mean arterial blood pressure (MAP), heart rate, rSO₂, pulse oximetry saturation (SpO₂), bispectral index, and body temperature were made. After spinal anesthesia, we measured these parameters every 5 min. Twenty minutes after spinal injection, dexmedetomidine or propofol administration was started. We measured each parameter at 10, 25, and 40 min after the administration of dexmedetomidine or propofol.

RESULTS

The baseline rSO₂ in the dexmedetomidine group was 71.3 ± 7.3%, and that in the propofol group was 71.8 ± 5.6%. After spinal anesthesia, rSO₂ in both groups decreased significantly (dexmedetomidine group: 65.4 ± 6.9%; propofol group: 64.3 ± 7.4%). After administering sedatives, rSO₂ was equivalent after spinal anesthesia. rSO₂ was comparable between the two groups. MAP and SpO₂ were significantly higher in the dexmedetomidine group than in the propofol group.

CONCLUSION

Spinal anesthesia decreased rSO₂; however, the decline was not severe. Dexmedetomidine and propofol did not compromise cerebral oxygenation under spinal anesthesia. Nevertheless, MAP and SpO₂ were more stable in dexmedetomidine sedation than in propofol sedation. Dexmedetomidine may be suitable for spinal anesthesia.

The application of near-infrared spectroscopy in oxygen therapy for premature infants

Objective: This study used near-infrared spectroscopy (NIRS) to detect the pulmonary regional oxygen saturation (rSO₂) of premature infants. The oxygenation state of the lung tissue was also evaluated, which provided preliminary evidence regarding the application of NIRS in oxygen therapy for premature infants.Methods: NIRS was used to measure the pulmonary rSO₂ of 26 premature infants (gestational age <32 weeks). The correlations between pulmonary rSO₂ and the arterial partial pressure of oxygen (PaO₂), arterial oxygen saturation (SaO₂), and pulse oxygen saturation (SpO₂) were analyzed. The diagnostic value of NIRS was evaluated via both Pearson's correlation and receiver operating characteristic (ROC) curve analyses.Results: Pulmonary rSO₂ was positively correlated with both PO₂ and SaO₂; the linear correlation coefficients (r) were 0.544 (p = .004) and 0.515 (p = .007), respectively. No significant correlation was found between rSO₂ and SpO₂ (p = .098). SpO₂ was positively correlated with PO₂ (r = 0.402, p = .042) and SaO₂ (r = 0.625, p = .001). NIRS could be used to predict hypoxemia (area under the curve [AUC] = 0.843; Youden's index =0.654) when the pulmonary rSO₂ was 62.39%, the sensitivity was 88.9%, and the specificity was 23.5% (p = .005) as well as predict hyperoxemia (AUC = 0.775; Youden's index = 0.65) when the pulmonary rSO₂ was 61.99%, the sensitivity was 100%, and the specificity was 35% (p = .045). SpO₂ predicted hypoxemia (AUC = 0.784, p = .019) but not hyperoxemia (AUC = 0.7, p = .144).Conclusion: NIRS objectively reflects the changes in oxygenation in the lung tissue. This study provides evidence for the clinical application of NIRS.