Jørgen E. Linde

Neonatal Outcome Following Cord Clamping After Onset of Spontaneous Respiration

BACKGROUND AND OBJECTIVE: Evolving data indicate that cord clamping (CC) beyond 30 to 60 seconds after birth is of benefit for all infants. Recent experimental data demonstrated that ventilation before CC improved cardiovascular stability by increasing pulmonary blood flow. The objective was to describe the relationship between time to CC, onset of spontaneous respirations (SR), and 24-hour neonatal outcome. METHODS: In a rural Tanzanian hospital, trained research assistants, working in shifts, have observed every delivery (November 2009–February 2013) and recorded data including time interval from birth to SR and CC, fetal heart rate, perinatal characteristics and outcome (normal, death, admission). RESULTS: Of 15 563 infants born, 12 780 (84.3%) initiated SR at 10.8 ± 16.7 seconds, and CC occurred at 63 ± 45 seconds after birth. Outcomes included 12 730 (99.7%) normal, 31 deaths, and 19 admitted; 11 967 were of birth weight (BW) ≥2500 g and 813 <2500 g. By logistic modeling, the risk of death/admission was consistently higher if CC occurred before SR. Infants of BW <2500 g were more likely to die or be admitted. The risk of death/admission decreased by 20% for every 10-second delay in CC after SR; this risk declined at the same rate in both BW groups. CONCLUSIONS: Healthy self-breathing neonates are more likely to die or be admitted if CC occurs before or immediately after onset of SR. These clinical observations support the experimental findings of a smoother cardiovascular transition when CC is performed after initiation of ventilation.

Normal Newborn Heart Rate in the First Five Minutes of Life Assessed by Dry-Electrode Electrocardiography.

Background: There is limited evidence regarding the heart rate (HR) during the first minutes of life. Nonetheless, resuscitative actions within the first minute are partly guided by different HR levels. The advent of an electrocardiographic (ECG) HR sensor with early HR detection has provided the opportunity to study changes immediately following delivery. Objective: The objectives were to determine immediately following delivery: (i) the time to achievement of reliable ECG signals using dry electrodes, (ii) changes in HR, and (iii) the influence of the onset of breathing and cord clamping on the HR. Methods: Healthy term neonates were randomly included between July and October 2013. The HR was recorded by the ECG sensor, placed over the abdomen immediately after birth. Results: Fifty-five newborns were included. The median time from birth to placement of the HR sensor was 3 s (quartiles: 2 and 5), and the median time to the start of breathing was 6 s (quartiles: 2 and 15). The HR was around 120 beats/min (bpm) in the first seconds of life. As determined via breakpoint analysis, the HR increased by 1 beat in the first 40 s to 149 ± 33 bpm, followed by a moderate increase until 130 s and stabilization thereafter. After the onset of breathing, the HR decreased for 10 s and then increased. Minimal HR changes were observed after cord clamping. Conclusion: A dry-electrode ECG sensor detected reliable ECG signals almost immediately after birth. The normal HR increased significantly in spontaneously breathing infants during the first minute, influenced by the onset of breathing. Delayed cord clamping had a minimal impact on the HR, likely reflecting an earlier onset of breathing.

The relation between given volume and heart rate during newborn resuscitation

BACKGROUND During delivery room resuscitation of depressed newborns, provision of appropriate tidal volume (TV) with establishment of functional residual capacity (FRC) is essential for circulatory recovery. Effective positive pressure ventilation (PPV) is associated with a rapid increase in heart rate (HR). The relationship between delivery of TV and HR responses remains unclear. OBJECTIVES The study objectives were to determine (1) the relationship between a given TV during initial PPV and HR responses of depressed newborns, and (2) the optimal delivered TV associated with a rapid increase in HR. METHODS In a Tanzanian rural hospital, ventilation and ECG signals were recorded during neonatal resuscitation and stored in Neonatal Resuscitation Monitors. Resuscitators without positive end-expiratory pressure were used for PPV. No oxygen was used. Perinatal events were observed and recorded by research assistants. RESULTS 215 newborns of gestational age 37.3±1.9 weeks and birth weight 3115±579g were included. There was a non-linear relationship between delivered TV and HR increase. TV of 9.3ml/kg produced the largest increase in HR during PPV. Frequent interruptions of PPV sequences to provide stimulation/suctioning occurred in all cases and were associated with further HR increases, especially for newborns with initial HR<100 beats/minute. CONCLUSIONS There was a consistent positive relationship between HR increase and delivered TV. The unanticipated finding of a further increase in HR with PPV pauses to provide stimulation/suctioning suggests that most newborns were in primary rather than secondary apnea.

Born not breathing: A randomised trial comparing two self-inflating bag-masks during newborn resuscitation in Tanzania

AIMS Effective ventilation is crucial to save non-breathing newborns. We compared standard equipment for newborn resuscitation to a new Upright bag, in an area with high neonatal mortality. METHODS Newborns requiring resuscitation at Haydom Lutheran Hospital, Tanzania, were ventilated with 230ml standard or 320ml Upright bag-mask by weekly non-blinded block randomisation. A Laerdal Newborn Resuscitation Monitor collected ventilation data through a flow sensor between mask and bag and heart rate with electrocardiography electrodes. Primary outcome was expiratory tidal volume per birth weight. RESULTS Of 6110 babies born, 136 randomised to standard bag-mask and 192 to Upright, both groups had similar birth weight, gestational age, Apgar scores, gender, and mode of delivery. Compared to standard bag-mask, Upright gave higher median expiratory tidal volume (8.6ml/kg (IQR: 3.5-13.8) vs. 10.0ml/kg (IQR: 4.3-16.8) difference ratio 1.29, 95%CI 1.05, 1.58, p=0.014)), increased mean airway and peak inspiratory pressures, and higher early expired CO2 (median at 20s 4.2% vs. 3.2%, p=0.0099). Clinical outcome 30min post-delivery was normal in 44% with standard versus 57% with Upright (p=0.016), but similar at 24h. CONCLUSION AND RELEVANCE Upright provided higher expired tidal volume, MAP, PIP and early ECO2 than the standard bag. Clinical outcome differed at 30min, but not at 24h. Larger volume of Upright than standard bag can be an important factor. The results are relevant for low- and high-income settings as ventilatory and heart rate parameters during resuscitation of newborns are rarely reported. Trial registered at www.ClinicalTrials.gov, NCT01869582.

Timing of cord clamping in relation to start of breathing or ventilation among depressed neonates—an observational study

The optimal timing of cord clamping (CC) in nonbreathing neonates needing stabilisation/resuscitation remains unclear. The objective was to describe the relationship between time to CC, initiation of breathing or positive pressure ventilation (PPV) after stimulation/suction and 24‐hour neonatal mortality/morbidity.

Detection of Activities During Newborn Resuscitation Based on Short-Time Energy of Acceleration Signal

Objectives: Clinical intervention for non-breathing newborns due to birth asphyxia needs to be conducted within the first minute of life. The responses of the babies are affected by complicated interactions between physiological conditions of the newborns and the combination of various clinical treatments, e.g., drying thoroughly, stimulation, manual bag-mask ventilation, chest compression, etc. Previously, we have proposed methods to detect and parameterize various events regarding bag mask ventilation. However, the outcome of the resuscitation is likely influenced by not only ventilation but also other therapeutics activities. The detection of the existence of activities using information from acceleration signals is illustrated in this paper. Methods: Short time energy of the acceleration signal is calculated. A thresholding method is applied on the amplitude of the energy signal to determine activity or rest. Results: The average sensitivity and specificity of the detection of activities are 90 % and 80 % respectively. Conclusions: The performance of the detection algorithm indicates the possibility to use acceleration signal to detect the presence of various activities during resuscitation procedure.

Exploratory Analysis of Ventilation Signals from Resuscitation Data of Newborns

Prevention of neonatal mortality and morbidity because of birth asphyxia is still a major challenge. In a non-breathing baby, resuscitation including manual ventilation should start within one minute after birth. Information extracted from ventilation signals might give a good indication of the effectiveness of therapy. A framework for exploratory data analysis was developed facilitating the development of signal parameters to identify the relationships between certain signal characteristics and various outcome groups. Low p-values found for some ventilation parameters indicates that the method presented could be useful in discovering factors and parameters that might be important for the outcome of ventilation therapy and for guiding further treatment.

Exploring the Relationship Between Characteristics of Ventilation Performance and Response of Newborns During Resuscitation

Birth asphyxia is one of the leading causes of newborn deaths in low resource settings. In non-breathing newborns, ventilation should commence within the first minute after birth. Ventilation signals were studied and parameterized to reflect the characteristics of the provided ventilation. The effectiveness of ventilation was characterized by changes in Apgar score and heart rate. A framework for exploring the association between ventilation parameters and the effectiveness of ventilation is proposed. A statistical hypothesis test method was used to calculate p-values for different patient groups for some ventilation parameters. The results show some low p-values indicating the possible correlation between the corresponding ventilation parameters and the outcome of the treatment.

Fresh stillborn and severely asphyxiated neonates share a common hypoxic–ischemic pathway

To characterize, among non‐breathing flaccid neonates at delivery, immediate heartrate and responses to ventilation in relation to the clinical diagnosis of fresh stillbirth (FSB) or early neonatal death (END) within 24 hours.

Automatic Detection and Parameterization of Manual Bag-Mask Ventilation on Newborns

Objectives: Birth asphyxia is a condition where a fetus suffers from lack of oxygen during birth. Intervention by manual ventilation should start within one minute after birth. Bag-mask resuscitators are commonly used in situations where ventilation is provided by a single health care worker. Due to a high complexity of interactions between physiological conditions of the newborns and the clinical treatment, the recommendations for bag-mask ventilation of infants remains controversial. The purpose of this paper is to illustrate the processing and parameterization of ventilation signals recorded from the Laerdal newborn resuscitation monitor into meaningful data. Methods: Basic signal processing approaches are applied on various signal channels (airway pressure, flow, CO