Cerebral blood flow velocities and cerebrovascular resistance in normal-term neonates in the first 72 hours.

AIM: To determine the range of cerebral blood flow velocities (CBFVs) and Doppler indices of cerebrovascular resistance in normal-term neonates as a baseline for a study of hypoxic-ischaemic encephalopathy. METHODS: The CBFVs, resistive index (RI) and pulsatility index (PI) were measured in the anterior and middle cerebral arteries (ACA and MCA) of 38 normal neonates. RESULTS: The mean peak systolic, end diastolic and time-averaged velocities (PSV, EDV and TAV) were 36.3 ± 6.6, 12.4 ± 3.9 and 22.0 ± 4.0 cm/s (ACA) and 41.4 ± 13.2, 13.0 ± 5.5 and 25.8 ± 7.9 cm/s (MCA), respectively. All CBFVs in the ACA correlated with gestation; only EDV was correlated to post-natal age. The RI in the ACA (0.67 ± 0.06) and MCA (0.68 ± 0.07) were correlated (r = 0.72, P < 0.001); RI correlated to post-natal age. Two infants with RI < 0.55 were both fed within 25 mins of the study; RI correlated with post-prandial time (dichotomous, pivot 25 min). The mean PI was 1.11 ± 0.18 (ACA) and 1.17 ± 0.23 (MCA). Correlations were observed with post-natal age and post-prandial time (dichotomous). The average angle of insonation was greater in the ACA than in the MCA (median of 5° vs. 18°). CONCLUSIONS: Results corresponded with previous published studies. No correlation was observed between Doppler indices and gestation as component velocities all increase with advancing gestation. Less variation and smaller standard deviation of CBFV's was associated with a smaller angle of insonation. Low RIs (<0.55), without a pathological cause, warrants further study.

Knowledge of Safety, Training, and Practice of Neonatal Cranial Ultrasound: A Survey of Operators.

OBJECTIVES: Ultrasound can lead to thermal and mechanical effects in interrogated tissues. This possibility suggests a potential risk during neonatal cranial ultrasound examinations. The aim of this study was to explore safety knowledge and training of neonatal cranial ultrasound among Australian operators who routinely perform these scans. METHODS: An online survey was administered on biosafety and training in neonatal cranial ultrasound, targeting all relevant professionals who can perform neonatal cranial ultrasound examinations in Australia: namely, radiologists, neonatologists, sonographers, and pediatricians. The survey was conducted between November 2013 and May 2014. RESULTS: A total of 282 responses were received. Twenty of 208 (10%) answered all ultrasound biosafety questions correctly, and 49 of 169 (29%) correctly defined the thermal index. Two-thirds (134 of 214 [63%]) of respondents failed to recognize that reducing the overall scanning time is the most effective method of reducing the total power exposure. Only 13% (31 of 237) indicated that a predetermined fixed period of training or that a specified minimum number of supervised scans was used during training. The reported number of supervised scans during training was highly variable. Almost half of the participants (82 of 181 [45%]) stated that they had received supervision for 10 to 50 scans (median, 20 scans). CONCLUSIONS: There is a need to educate operators on biosafety issues and approaches to minimize power outputs and reduce the overall duration of cranial ultrasound scans. Development of standardized training requirements may be warranted.

Declining invasive prenatal diagnostic procedures: A comparison of tertiary hospital and national data from 2012 to 2015.

BACKGROUND: In recent years, the superior accuracy of maternal plasma cell-free DNA-based prenatal screening has resulted in >50% national decline in amniocenteses and chorionic villus sampling (CVS), creating new implications for specialist training. OBJECTIVE: To compare the annual figures on amniocenteses and CVS in a tertiary hospital with national population-based trends between 2012 and 2015. METHODS: Retrospective study examining the amniocentesis and CVS procedures performed in a tertiary hospital between 2012 and 2015. Numbers of procedures, indications for testing, type of test and diagnostic results were analysed. Trends in the annual numbers of procedures were compared to national population-based data from Medicare Benefits Schedule database. RESULTS: The annual numbers of diagnostic procedures in our tertiary centre fell from 267 to 215 over the study period, representing a 19.5% decline. This was significantly smaller than the corresponding national decline of 53.7% for the same period (P < 0.0001). In 2015, ultrasound abnormality (including nuchal translucency ≥ 3.5 mm) surpassed high-risk screening results as the most common indication for invasive testing. Thirty percent of procedures performed for an ultrasound abnormality occurred prior to 18 weeks gestation. CONCLUSION: Our tertiary centre experienced a relatively smaller decline in prenatal diagnostic procedures compared with national figures, largely due to an increase in testing for ultrasound abnormalities. Our results demonstrate the increasing contribution of first trimester ultrasound in the detection of fetal abnormalities in the cell-free DNA era and the continued viability of specialist training in invasive procedures.

Accuracy of a Weight-Based Formula for Neonatal Gastric Tube Insertion Length.

BACKGROUND: Gastric tubes are used in nurseries on a daily basis. Various methods of estimating gastric tube length for insertion using anatomical landmarks are used to assist correct placement. Sometimes, however, they can be up to 55% inaccurate. In 2012, we published a weight-based formula to estimate gastric tube length for insertion. PURPOSE: This study reviews the rates of correct gastric tube placement, as confirmed by radiography, after the incorporation of this weight-based formula into bedside practice. METHODS: A 6-month prospective study was performed in a tertiary neonatal intensive care unit. The formula estimating gastric tube length for insertion had been derived in an earlier study. This was incorporated into the hospital's policies and procedures guideline for the insertion of gastric tubes. Neonates with gastric tubes who required radiography for clinical reasons were included. The infant's weight and the type (orogastric or nasogastric) and length of tube were documented. A single radiologist assessed the tube position to be high, borderline, correct, or long. RESULTS: A total of 195 chest radiographs were obtained. Correct tube position was found in 84% of instances. This was a statistically and clinically significant improvement. IMPLICATIONS FOR PRACTICE: Implementation of a simple weight-based estimate for gastric tube length improves correct position rates. IMPLICATIONS FOR RESEARCH: Further studies comparing accuracy of length/height and weight-based estimations for gastric tube insertion lengths in very preterm and extremely preterm infants are needed.

Medical management of retained products of conception: A prospective observational study.

OBJECTIVE(S): To measure the success rate of primary medical therapy in managing retained products of conception (RPOC) in women with secondary postpartum haemorrhage (PPH) and to identify factors associated with need for surgical management. STUDY DESIGN: Postpartum patients presenting to a tertiary women's hospital Emergency Department between July 2020 and December 2022 with secondary PPH and evidence of RPOC on ultrasound were recruited. Clinical information relating to the presentation was collected prospectively. Antenatal and intrapartum data were collected from medical record and Birthing Outcome System database review. The primary outcome was the success of medical management for RPOC, defined by the implementation of medical or expectant management without subsequent need for surgical intervention. RESULTS: Forty-one patients with RPOC underwent primary medical or expectant management. Twelve patients (29%) were managed successfully with medical management, while twenty-nine (71%) proceeded to surgical management. Medical management involved antibiotics (n = 37, 90%), prostaglandin E1 analogue (n = 14, 34%) and other uterotonics (n = 3, 7%). A greater endometrial thickness on ultrasound was significantly associated with a requirement for secondary surgical intervention (p < 0.05). There was an association approaching statistical significance between a higher sonographic volume of RPOC and the failure of medical management (p = 0.07). There was no statistically significant association between the mode of delivery or the number of days postpartum with the success of medical management. CONCLUSION(S): For patients presenting with secondary PPH and sonographic RPOC, over two thirds required surgical management. Increased endometrial thickness was associated with an increased requirement for surgical management.

A weight-based formula for the estimation of gastric tube insertion length in newborns.

OBJECTIVE: Safe and effective functioning of nasogastric and orogastric tubes in the neonatal intensive care unit (NICU) is achieved by ensuring their correct placement within the stomach. Insertion length has traditionally been estimated using morphological measures, but studies have indicated that these are frequently inaccurate. This study aimed to evaluate the frequency of correct tube placement and to determine a weight-based formula for estimation of insertion length. STUDY DESIGN: A prospective study was performed over a 6-month period in a tertiary NICU. Infants with gastric tubes who required radiography for clinical reasons were included. The infant's weight and the type and length of tube were documented. A radiologist assessed the tube position to be high, borderline, correct, or long. RESULTS: A total of 218 radiographs of infants weighing 397 to 4131 g were included. Correct tube position was achieved on 74% of occasions. By analyzing data for correct tube positions, formulas were derived to predict tube insertion length in centimeters: orogastric = [3 × weight (kg) + 12] and nasogastric = [3 × weight (kg) + 13]. The formulas correctly predicted 60% of misplaced orogastric tubes and 100% of misplaced nasogastric tubes. CONCLUSION: We propose a novel weight-based formula for estimation of gastric tube insertion length in newborn infants to improve the accuracy of this routine procedure.

Surveillance Practice for Sonographic Detection of Intracranial Abnormalities in Premature Neonates: A Snapshot of Current Neonatal Cranial Ultrasound Practice in Australia.

There are no publications reporting on scan duration and Doppler use during neonatal cranial ultrasound scans. We investigated current practice of neonatal cranial ultrasound at four large tertiary neonatal intensive care units in Australia. Cranial scans were prospectively recorded between March 2015 and November 2016. Variables, including total number of scans, scan duration and frequency and duration of colour and spectral Doppler mode, were extracted. A total of 196 scans formed the final cohort. The median (range) number of scans for each neonate was 1 (1-12). The median (range) overall total scan duration was 309 (119-801) s. Colour mode with or without spectral Doppler mode was used in approximately half of the cohort (106/196, 54%). Our findings comport with our hypotheses. Operators performing neonatal cranial scans in Australia have low overall scan durations. Although the use of Doppler mode during neonatal cranial scans is not standard practice in all neonatal intensive care units, it is used widely irrespective of the degree of prematurity or the presence of brain pathology. Further efforts are required to incorporate recommendations on scan duration and the routine use of Doppler mode during neonatal cranial scans. This is especially imperative given that the most vulnerable neonates with the greater neural tissue sensitivity are likely to be scanned more often.