Comparison of different types of ultrasound probes for lung ultrasound in neonates-A prospective randomized comparison study.

OBJECTIVE: To determine the effect of different types of probes for lung ultrasound in neonates. DESIGN: Prospective, blinded, randomized, comparative study between 2020 and 2022. SETTING: Single-center study at a third level neonatal unit. PATIENTS: Hemodynamically stable infants with either nasal continuous positive airway pressure, high flow nasal cannula or without respiratory support. INTERVENTION: Lung ultrasound using either an echo or microconvex probe. As control, the linear probe was used. MAIN OUTCOME MEASURES: Primary outcome measure was neonatologist performed lung ultrasound (NPLUS) score. Secondary outcome measures were number of B-Lines, thickness of the pleural line and subjective image quality. Furthermore, correlation between NPLUS results and clinical data was assessed. RESULTS: A total of 1584 video loops from 66 patients, with a mean corrected gestational age of 33.8 weeks (SD 4.23) and weight of 1950g (SD 910), respectively, were analyzed. NPLUS score was estimated lower with the echo- and microconvex probe compared to the linear probe, with a coefficient of -2.95 (p < 0.001) and -1.09 (p = 0.19), respectively. Correlation between the pulse oximetric saturation/fraction of inspired oxygen ratio and NPLUS score was moderately strong and best using the microconvex probe (Spearman's rho = -0.63, p<0.001). CONCLUSION: Our results not only confirm the current recommendations, but also demonstrate the extent of the varying results when different probes are used. The differences we discovered call for caution in interpreting scores, especially in the context of guiding therapies and communicating prognoses. Finally, the correlation between NPLUS score and clinical parameters contributes to validating the use of this diagnostic tool.

Regular lung recruitment maneuvers during high-frequency oscillatory ventilation in extremely preterm infants: a randomized controlled trial.

BACKGROUND: Lung recruitment maneuvers (LRMs) improve lung volume at initiation of high-frequency oscillatory ventilation (HFOV), but it is unclear when to repeat LRMs. We evaluated the efficiency of scheduled LRMs. METHODS: In a randomized controlled trial, extremely preterm infants on HFOV received either LRMs at 12-hour intervals and when clinically indicated (intervention) or only when clinically indicated (control). The primary outcome was the cumulative oxygen saturation index (OSI) over HFOV time, limited to 7 days. Additionally, LRMs were analyzed with respect to OSI improvement. RESULTS: Fifteen infants were included in each group. The mean (SD) postmenstrual age and weight at HFOV start were 23 + 6 (0 + 5) weeks and 650 (115) g in the intervention group and 24 + 4 (0 + 6) weeks (p = 0.03) and 615 (95) g (p = 0.38) in the control group. The mean (SD) cumulative OSI amounted to 4.95 (1.72) in the intervention versus 5.30 (2.08) in the control group (p = 0.61). The mean (SD) number of LRMs in 12 h was 1.3 (0.2) in the intervention versus 1.1 (0.5) in the control group (p = 0.13). Performing LRM when FiO2 > 0.6 resulted in a mean OSI reduction of 3.6. CONCLUSION: Regular versus clinically indicated LRMs were performed with equal frequency in preterm infants during HFOV, and consequently, no difference in lung volume was observed. LRMs seem to be most efficient at high FiO2. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT04289324 (28/02/2020).

Monitoring of carbon dioxide in ventilated neonates: a prospective observational study.

OBJECTIVE: To assess the reliability, accuracy and precision of distal end-tidal capnography (detCO2) in neonates compared with transcutaneous (tcCO2) carbon dioxide measurements. DESIGN: Observational, prospective clinical study. SETTING: Neonatal intensive care unit at Medical University of Vienna. PARTICIPANTS: Conventionally ventilated neonates with a body weight between 1000 g and 3000 g. INTERVENTION: End-tidal partial pressure of CO2 was measured in distal position using the separate lumen of a double-lumen endotracheal tube connected to an external side-stream capnometer. Three consecutive detCO2 and tcCO2 values were recorded simultaneously and compared with simultaneous arterialised partial pressure of CO2 (paCO2) measurements in each patient. MAIN OUTCOME MEASURES: Reliability, accuracy and precision of detCO2 and tcCO2 measurements compared with paCO2 in neonates. RESULTS: Twenty-five neonates were included with a median (range) weight at enrolment of 1410 (1010-2980) g, from which 81 simultaneous measurements of detCO2, tcCO2 and paCO2 were obtained. The mean (SD) of paCO2, detCO2 and tcCO2 was 45.0 (8.6) mmHg, 42.4 (8.4) mmHg and 50.4 (20.4) mmHg, respectively. The intraclass correlation between paCO2 and detCO2 and between paCO2 and tcCO2 reached 0.80 (95% CI 0.71 to 0.87, p<0.001) and 0.59 (95% CI 0.43 to 0.72, p<0.001), respectively. In the Bland-Altman analysis, bias and precision of detCO2 with respect to paCO2 amounted to -2.68 mmHg and 10.62 mmHg (95% CI 8.49 to 14.51), respectively. Bias and precision of tcCO2 with respect to paCO2 amounted to 5.39 mmHg and 17.22 mmHg (95% CI 13.21 to 23.34), respectively. CONCLUSION: DetCO2 had better reliability, accuracy and precision with paCO2 than tcCO2 in ventilated neonates without severe lung diseas. TRIAL REGISTRATION NUMBER: NCT03758313.

The Role of Lung Ultrasound in the Management of the Critically Ill Neonate-A Narrative Review and Practical Guide.

Lung ultrasound makes use of artifacts generated by the ratio of air and fluid in the lung. Recently, an enormous increase of research regarding lung ultrasound emerged, especially in intensive care units. The use of lung ultrasound on the neonatal intensive care unit enables the clinician to gain knowledge about the respiratory condition of the patients, make quick decisions, and reduces exposure to ionizing radiation. In this narrative review, the possibilities of lung ultrasound for the stabilization and resuscitation of the neonate using the ABCDE algorithm will be discussed.

Mirrored Ribs: A Sign for Pneumothorax in Neonates.

OBJECTIVES: To evaluate if "mirrored ribs"-a mirroring of chest structures-is a sign for pneumothorax in lung ultrasound in neonates. DESIGN: Retrospective study. SETTING: Medical University Vienna/General Hospital, Vienna, Austria. PATIENTS: All neonates admitted with clinical signs of pneumothorax between July 2018 and February 2019. INTERVENTIONS: Chest radiograph and lung ultrasound in succession. MEASUREMENTS AND MAIN RESULTS: Anterior-posterior chest radiograph and lung ultrasound were compared. "Mirrored ribs" were defined as mirroring of at least one rib and intercostal muscles in B-mode in the absence of B-lines. Twenty-nine cases in 26 patients were considered. Pneumothorax was diagnosed in 55% of cases using reported signs for pneumothorax in lung ultrasound and in 31% using chest radiograph. Lung ultrasound identified all pneumothoraces visible in chest radiograph. "Mirrored ribs" were visible in all patients with signs for pneumothorax and in none without signs for pneumothorax in lung ultrasound, representing a specificity and sensitivity of 100% compared with reported signs for pneumothorax in lung ultrasound. CONCLUSIONS: The occurrence of "mirrored ribs" in lung ultrasound in combination with absence of lung sliding, absence of B-lines and lung point might facilitate the rapid recognition of pneumothorax in neonates.

Discrepancy between invasive and non-invasive blood pressure readings in extremely preterm infants in the first four weeks of life.

BACKGROUND: The agreement between invasive and non-invasive blood pressure (BP) readings in the first days of life of preterm infants is contentiously debated. OBJECTIVE: To compare mean, systolic and diastolic invasive (IBP) and non-invasive BP (NBP) readings obtained during routine care in the first four weeks of life of extremely preterm infants. METHODS: We extracted pairs of IBP and NBP readings obtained from preterm infants born below 28 weeks of gestation from the local database. After exclusion of erroneous measurements, we investigated the repeated measures correlation and analyzed the agreement (bias) and precision adjusted for multiple measurements per individual. RESULTS: Among 335 pairs of IBP and NBP readings obtained from 128 patients, we found correlation coefficients >0.65 for mean, systolic and diastolic BP values. The bias for mean BP readings was -0.4 mmHg (SD 6.1), for systolic BP readings 6.2 mmHg (SD 8.1), and for diastolic BP readings -4.3 mmHg (SD 6.5). Overestimation of systolic IBP and underestimation of diastolic IBP by the non-invasive measurement were found both in the group with gestational age from 23 to 25.9 weeks and in the group with gestational age from 26 to 27.9 weeks. Systolic NBP readings tended to exceed invasive readings in the range <50 mmHg (bias 9.9 mmHg) whereas diastolic NBP readings were lower than invasive values particularly in the range >30 mmHg (bias -5.5 mmHg). CONCLUSION: The disagreement between invasive and non-invasive BP readings in infants extends to the first four weeks of life. Biases differ for mean, systolic and diastolic BP values. Our observation implies that they may depend on the range of the blood pressure. Awareness of these biases and preemptive concomitant use of IBP and NPB readings may contribute to reducing over- or under-treatment.