Intervention and Outcome for Neonatal Hypotension

Accuracy and Reproducibility of a Modified Echocardiographic Method for Right Ventricular Output Calculation in Neonates

We aimed to evaluate the accuracy and reproducibility of right ventricular output (RVO) using different anatomical landmarks: the internal pulmonary valve diameter (PVD) between the valve hinge points (hinge-PVD) according to the traditional technique, and PVD between the valve leaflet tips (tip-PVD). This was a retrospective analysis of prospective collected data. All neonates with echocardiographic measurements of RVO and left ventricular output (LVO) without congenital heart disease, including patent ductus arteriosus and patent foramen ovale > 3 mm, were included. Accuracy was assessed by comparison with LVO. Intra- and inter-observer reproducibility of the off-line analysis were assessed. Forty-five neonates were included. RVO calculation with tip-PVD was more accurate than hinge-PVD in comparison with LVO, r2 0.712 versus 0.464, bias (95% limits of agreement) 1.4 mL/kg/min (-26-29 mL/kg/min) versus 61 mL/kg/min (-11-132 mL/kg/min), respectively. Both hinge-PVD and tip-PVD presented similar reproducibility, with an intra-observer bias (95% LOA) of 0.3 (-1.0-0.5) and -0.2 (-0.8-0.5) respectively, and an inter-observer bias of 0.1 (-1.3-1.6) and 0.1 (-1.4-1.6). RVO calculation using tip-PVD was more accurate than the conventional technique, with similar reproducibility.

Haemodynamic assessment and management of hypotension in the preterm

The management of low blood flow states in premature neonates is fraught with many challenges. We remain over-reliant on regimented stepwise protocols that use mean blood pressure as a threshold for intervention to guide treatment, without giving due consideration to the underlying pathophysiology. The current available evidence does not reflect the need to concentrate on the unique pathophysiology of the preterm infant and thus leads to widespread misuse of vasoactive agents that often do not provide the desired clinical effect. Therefore, understanding the underlying pathophysiological underpinnings of haemodynamic compromise may better guide choice of agent and assess physiological response to the selected intervention.

[Risk factors and prognosis of hypotension within 72 hours after birth in extremely preterm infants]

OBJECTIVES

To investigate the risk factors and prognosis of hypotension within 72 hours after birth in extremely preterm infants.

METHODS

A retrospective analysis was conducted on clinical data of extremely preterm infants admitted to the Children's Hospital of Zhejiang University School of Medicine from January 2019 to April 2022. Based on the presence of hypotension within 72 hours after birth, the eligible infants were divided into a hypotension group (41 cases) and a normotension group (82 cases). The clinical characteristics, echocardiographic parameters within 72 hours after birth, and early complications were compared between the two groups. Multivariate logistic regression analysis was used to explore the risk factors for hypotension within 72 hours after birth, and receiver operating characteristic curve analysis was performed to evaluate the predictive value of relevant indicators for the occurrence of hypotension within 72 hours after birth in the preterm infants.

RESULTS

The proportion of infants who required medication or surgical closure of patent ductus arteriosus (PDA), the proportions of infants with intraventricular hemorrhage ≥ grade III and severe pulmonary hemorrhage, and the mortality rate within 7 days in the hypotension group were significantly higher than those in the normotension group (P<0.05). Multivariate logistic regression analysis showed that lower birth weight, larger PDA diameter, and hemodynamically significant PDA were risk factors for the occurrence of hypotension within 72 hours after birth in extremely preterm infants (P<0.05). The receiver operating characteristic curve analysis showed that the combination of birth weight, PDA diameter, and hemodynamically significant PDA had an area under the curve of 0.873 (95%CI: 0.802-0.944, P<0.05) for predicting hypotension within 72 hours after birth, with a sensitivity of 73.2% and specificity of 91.5%.

CONCLUSIONS

Hypotension within 72 hours after birth is closely related to birth weight and PDA, and increases the risk of early severe complications and mortality in extremely preterm infants.

Comparison of clinical outcomes between active and permissive blood pressure management in extremely preterm infants

Background

There remains uncertainty about the definition of normal blood pressure (BP), and when to initiate treatment for hypotension for extremely preterm infants. To determine the short-term outcomes of extremely preterm infants managed by active compared with permissive BP support regimens during the first 72 hours of life.

Method

This is a retrospective medical records review of 23 +0-28 +6 weeks' gestational age (GA) infants admitted to neonatal units (NNU) with active BP support (aimed to maintain mean arterial BP (MABP) >30 mmHg irrespective of the GA) and permissive BP support (used medication only when babies developed signs of hypotension) regimens. Babies admitted after 12 hours of age, or whose BP data were not available were excluded.

Results

There were 764 infants admitted to the participating hospitals; 671 (88%) were included in the analysis (263 active BP support and 408 permissive BP support). The mean gestational age, birth weight, admission temperature, clinical risk index for babies (CRIB) score and first haemoglobin of infants were comparable between the groups. Active BP support group infants had consistently higher MABP and systolic BP throughout the first 72 hours of life (p<0.01). In the active group compared to the permissive group 56 (21.3%) vs 104 (25.5%) babies died, and 21 (8%) vs 51 (12.5%) developed >grade 2 intra ventricular haemorrhage (IVH). Death before discharge (adjusted OR 1.38 (0.88 - 2.16)) or IVH (1.38 (0.96 - 1.98)) was similar between the two groups. Necrotising enterocolitis (NEC) ≥stage 2 was significantly higher in permissive BP support group infants (1.65 (1.07 - 2.50)).

Conclusions

There was no difference in mortality or IVH between the two BP management approaches. Active BP support may reduce NEC. This should be investigated prospectively in large multicentre randomised studies.

Echocardiography performed by the neonatologist: the impact on the clinical management

BACKGROUND

The aim of this study was to assess whether neonatologist-performed echocardiography (NPE) changed the previously planned hemodynamic approach in critically ill newborn infants.

METHODS

This prospective cross-sectional study included the first NPE of 199 neonates. Before the exam, the clinical team was asked about the planned hemodynamic approach and the answer was classified as an intention to change or not to change the therapy. After being informed about the NPE results, the clinical management was grouped as performed as previously planned (maintained) or modified.

RESULTS

NPE modified the planned pre-exam approach in 80 cases (40.2%; 95% CI: 33.3-47.4%), and variables associated with an increased chance of this modification were exams to assess pulmonary hemodynamics (prevalent ratio (PR): 1.75; 95% CI: 1.02-3.00) and to assess systemic flow (PR: 1.68; 95% CI: 1.06-2.68) in relation to those requested for patent ductus arteriosus, pre-exam intention of changing the prescribed management (PR: 2.16; 95% CI: 1.50-3.11), use of catecholamines (PR: 1.68; 95% CI: 1.24-2.28) and birthweight (per kg) (PR: 0.81; 95% CI: 0.68-0.98).

CONCLUSION

The NPE was an important tool to direct hemodynamic management in a different approach from the previous intention of the clinical team, mainly for critically ill neonates.

IMPACT

This study shows that neonatologist-performed echocardiography guides the therapeutic planning in the NICU, mainly in the more unstable newborns, with lower birthweight and receiving catecholamines. Exams requested with the intention of modifying the current approach were more likely to change the management in a different way than planned pre-exam.

Non-invasive cardiac output monitoring before and after baby extubation - A feasibility study (NICOMBabe study)

BACKGROUND

Mechanical ventilation induces changes in intrapleural, intrathoracic and intra-abdominal pressure. These changes have various implications on cardiac output (CO).

AIMS

The aim of this study was to determine the feasibility of measuring changes in CO after elective extubation in neonates using the principle of transthoracic bioreactance (TBR).

STUDY DESIGN

This was a prospective observational cohort study in a level III neonatal centre. CO, stroke volume (SV) and heart rate were measured continuously for 2 h before and 2 h after elective extubation by TBR.

SUBJECTS

Neonates undergoing elective extubation were eligible for enrolment.

OUTCOME MEASURES

The primary outcome of the study was change in CO post elective extubation.

RESULTS

Ten neonates were enrolled, seven (70 %) had a statistically significant decrease in CO after extubation, three (30 %) infants had a statistically significant increase in CO after extubation. Changes in CO were primarily driven by changes in SV and the pattern of change was related to patent ductus arteriosus (PDA) status prior to extubation.

CONCLUSION

Extubation significantly influences CO in neonatal patients and the pattern of change appears to be related to PDA status.

Hemodynamic management of the micropreemie: When inotropes are not enough

Managing perfusion in the micropreemie is challenging and should be guided by the patho-physiology, gestational and postnatal age of the baby, perinatal history, and the persistence of fetal shunts. The assessment should incorporate bedside tools such as blood pressure, clinical perfusion markers, and functional echocardiography. The multimodal approach to diagnose and identify the cause of hemodynamic compromise paves the way to a targeted approach to treatment. Characterizing the predominant pathophysiologic cause of low cardiac output and impaired cellular metabolism enables a more accurate use of inotropes, vasopressors, and volume support to suit a particular pathophysiologic situation.