Measuring the increase in exhaled carbon dioxide in spontaneously breathing infants at birth, the RISE study

This is a prospective, observational study of spontaneously breathing term and late preterm infants in the delivery room. The primary outcome will be the measured exhaled carbon dioxide levels in the first ten minutes of life. A combined neonatal CO2/Flow sensor (Neonatal CO2 Flow Sensor, Phillips Healthcare, Massachusetts, USA) will be attached to a face mask (Laerdal round mask, Laerdal, Stavanger, Norway or Neonatal Resuscitation Masks, Fisher&Paykel, Auckland, New Zealand). Immediately after birth, a face mask will be placed over the mouth and the nose. Infants will breathe through the mask. The NM3 Respiratory Profile Monitor (Phillips Healthcare, Massachusetts, USA). consists of a combined CO2/Flow sensor which measures exhaled carbon dioxide with an infrared light beam at different wavelengths in order to precisely determine gas concentrations in the expired breaths. In addition, the monitor can record pulse and SpO2 via pulse oximetry, with a 2 second averaging time. The respiratory gas measurements are obtained by continuously measuring the infrared light absorption in gas flow through an adapter in the breathing circuit. Gas flow, tidal volume, respiratory rate and airway pressures are measured with a flow sensor. The dead space of the CO2/Flow neonatal sensor is less than 1 mL according to the manufacturer and unlikely to interfere with breathing. We plan to obtain the measurements immediately after the baby is delivered and continue whilst the baby is lying on the mother’s chest. The purpose of the study is to measure exhaled carbon dioxide during the transition of a healthy newborn, starting with the baby’s first breath. The natural transition of the healthy newborn includes bonding with the mother after birth. To minimize interference with the normal monitoring and stabilization of preterm and term infants after birth, we will record respiratory measurements for the first 60 seconds of life, then record 10-20 breaths every 1 minute for the first ten minutes of life, at 1-2 hours of life, and at 12-72 hours of life. The intermittent application of the facemask during the first 10 minutes of life will reduce the small risk of rebreathing carbon dioxide in the circuit’s dead space and will allow for a more natural neonatal transition. During data collection, breaths will be counted if the investigator feels that there is a proper mask seal and leak is minimal. During the study, if there are any signs of respiratory compromise, the study will be abandoned and ventilatory support given according to the Australian Neonatal Resuscitation guidelines. After a vaginal delivery, data will be collected whilst the baby is on the mother’s chest. If the baby cannot be held by the mother (or other family member), the baby can be positioned close to the mother and placed on a dedicated research trolley with a warming mattress during data collection. In the event of a caesarian section delivery, we will also collect data immediately after delivery. One of the researchers will scrub and don sterile gown and gloves and stand next to the delivering consultant. A dedicated research trolley with a warming mattress and sterile drapes will be placed close to the surgical field. A plastic sterile sheathing will be placed over the flow sensor tubes and wires. Two holes will be cut into the sheath and secured with sterile ties, one for a sterile mask to connect to the flow sensor and one for the distal end of the flow sensor. If the obstetric team feels that we are interfering with patient care, the study will be abandoned. After the baby is placed onto the research trolley with a warming mattress and moved out of the sterile field, a pulse oximetry sensor will be placed on the infant’s right hand or wrist. Once the baby is out of the sterile field, the process of data collection after a caesarean delivery will be the same as for a vaginal delivery. The study should not preclude skin to skin contact of babies with their mothers after a caesarean delivery in the first ten minutes of life. The data acquisition system that will be used for this study is portable and will be housed on a research trolley with a warming mattress that can move with the baby from the sterile field to the resuscitation bed for evaluation and then to the head of the bed so that the baby can bond with the mother. The natural transition of the healthy newborn includes bonding with the mother after birth. Our goal is to minimize interference with this process. The pulse oximeter will record continuously for the first 10 minutes of life, then the sensor will be removed. We will record the baby’s temperature at 10-12 minutes of life. The pulse oximeter will be reapplied at the 1-2 hour and 12-72 hour recordings. We aim to record the exact timing of several events that occur in the first 2 minutes after the birth of the neonate, including the time the facemask is applied, the time the cord is clamped, the time the baby first breaths/cries, and the time that the pulse oximetry sensor is placed on the baby’s right wrist. After some trial and error recording events during routine deliveries, we feel that we will achieve a high fidelity accounting of these events after birth by making a de-identified audio recording of the investigator dictating the sequence of events into an audio recorder (an iphone placed in the investigators chest pocket). Immediately after the delivery, we will record the timing of events onto a patient data form and erase the audio recording. If available, we will also record the umbilical arterial cord blood gas for analysis. The signals of airway flow, tidal volumes, airway pressure, breathing pattern, exhaled carbon dioxide, heart rate, and SpO2 will be converted from analog to digital signal and recorded at 100Hz using a custom built software program which presents the data in graphical and table form. Measurements recorded will be analyzed using Stata Software (StataCorp, College Station, Texas, USA) for statistical analysis. We plan to review the data collected after enrolling 10, 20, and 50 babies. The purpose will be to review patient safety and efficacy of data collection. Specifically, we will monitor the baby’s temperature at 10-12 minutes, the risk of breaking the sterile field in caesarian sections, the potential of interfering with patient care, and need for resuscitation (apart from routine drying and stimulation). The measurements obtained from this cohort of babies constitutes an observational study. This data will provide valuable information on exhaled carbon dioxide in the first minutes after birth.