It invariably affects other functions and organ systems. Better methods than PaO 2 and SpO 2 for assessing tissue oxygenation and altered redox status in clinical practice may some day become available.
Until then, identifying practices that reduce the risk of potential hyperoxic damage can only be beneficial for many babies. SpO 2 is considered the fifth vital sign, 6 of value to detect hypoxemia, but it cannot reveal hyperoxemia.
SpO 2 monitors were introduced into practice without adequate education for healthcare providers responsible for data interpretation and administration of the fraction of inspired oxygen FiO 2. Therefore, the monitors are not well understood by many clinicians.
In addition, the performance of SpO 2 monitors is not uniform. The advantages of SpO 2 monitors with signal extraction technology Masimo SET during situations of low perfusion and motion have been previously described.
SpO 2 monitoring is based on the relation between hemoglobin Hb and oxygen. Bohr showed that the dissociation curve was sigmoid shaped, with an initial relative horizontal portion, followed by a vertical one, ending again with a horizontal shape. When PaO 2 is low, Hb gets rid of the oxygen, so the little oxygen available is given to the tissues.
On the other hand, Hb affinity for oxygen increases as successive molecules of oxygen bind after a certain PaO 2 level has been reached. They all affect the P Oxygen delivery to the tissues and cells depends on this and is influenced by O 2 consumption and the complex interplay of many factors Figure 1. We do not know which value of PaO 2 is critical in neonates. This oxygen content is likely to be sufficient to avoid neonatal tissue hypoxia at usual ranges and interactions of the factors described in Figure 1 with oxygen consumption.
Above a certain, though not precisely known, PaO 2 level, the dissolved PaO 2 is unnecessary and potentially harmful.
However, why expose infants to risk as low as it may be if lower PaO 2 without hypoxemia can meet all demands at the tissue and cellular levels?
A saturation value measured by a blood gas machine should never be used. The Food and Drug Administration requires that SpO 2 monitors be calibrated to display functional saturation. However, the bias, accuracy and precision of the equipment are different, more so during unstable conditions and at lower SpO 2.
Since some monitors are better than others, a similar or even larger disparity in SpO 2 simultaneous readings between different SpO 2 monitors exists. Therefore, accepting the imprecision of the real world, the one SpO 2 value cannot be the sole focus. It is much more reasonable to work with ranges of SpO 2. Table 1 Table 2 summarizes this paper's findings. This PaO 2 may be too low for a specific infant. This can be explained by adequate pulmonary blood flow, minimal extra- and intrapulmonary shunting as it can occur with CPAP or IMV , lower alveolar pressures of CO 2 , and subsequent increase in alveolar pressure of oxygen.
Today's best neonatal clinical practice has led to improved outcomes, 18 but many neonatal practices may be impacting the neonatal brain unfavorably. We must turn off the lights and the oxygen when not necessary to avoid a potentially bad combination. Oxygen, a potent oxidant, is a health hazard if inhaled in excess. The potential detrimental effects associated with oxygen include retinopathy of prematurity ROP , bronchopulmonary dysplasia BPD , increase length of stay LOS , impaired brain development and possibly infection and cancer.
ROP remains the leading cause of blindness and vision impairment in children, despite advances in care. Wright et al. We found only one study suggesting that changing practice is not associated with improvements in ROP. There are other potential benefits of avoiding high SpO 2 targets and decreasing the amount of oxygen given to infants. This change in practice, did not have a detrimental effect on neurodevelopmental outcomes at 18 months corrected age, but the Bayley scores actually improved.
Sepsis is one of the leading causes of morbidity and mortality in the neonatal unit. Oxygen is an immune modulator. If the antioxidant mechanism is deficient or overwhelmed by excess oxygen, the harmful and toxic effects of ROS could depress the immune response. We recently reported that the response to this change in practice yields better effects in girls than in boys.
Mental changes with oxygen therapy in human adults were reported by Comroe over 50 years ago. This seems to be the case in human neonates. Hyperoxia independently contributed to the risk of disabling cerebral palsy CP in very-low birth weight infants mechanically ventilated 50 and was also found to increase adverse outcomes, including CP, after perinatal hypoxia-ischemia encephalopathy in term newborns.
The risk of high PaO 2 may start during the first minutes of life. In the delivery room, oxygen may trigger a cascade of events that may be impossible to stop, despite the best NICU care. Pure oxygen must be avoided because of its toxicity even for a short period of time.
Finally, who would have imagined that only a few minutes of oxygen could be associated with childhood cancer? A small fraction of the oxygen consumed by the mitochondria is constantly converted to superoxide radical anions, hydrogen peroxide, hydroxyl radicals and other ROS. Their excess can modify the intracellular redox status, altering signal transduction, enzyme activation and protein, DNA and RNA synthesis, leading to aging and cancer.
Healthcare providers do that for them. It is clear that changes in practices are necessary, trying to avoid neonatal hyperoxemia in the delivery room, the NICU, the operating room and during transport and diagnostic studies. We summarize some of these practices in Table 2. In Table 3 we summarize some other issues regarding clinical care with supplemental oxygen, in order to improve neonatal daily care of oxygen administration and monitoring.
These issues include necessary equipment, clinical assessment and actions during procedures, apnea and manual ventilation. In addition, Table 3 presents one approach regarding increases and wide fluctuations of FiO 2 and stresses the important issues of not turning SpO 2 alarms off and keeping SpO 2 readings within acceptable SpO 2 ranges. Finally, it is imperative to decrease the FiO 2 if the SpO 2 reading is as good as it is normally in room air Table 3.
In the newborn, oxygen is more toxic than originally believed. Our understanding of the potential serious toxic damage that we can induce by administering excessive oxygen to breathe is improving.
We have failed in clinical practice by exposing many newborns worldwide to high oxygen levels and hyperoxic states when trying to prevent hypoxia. What can we do? Remind ourselves that treating hypoxemia is not the same as inducing hyperoxia. We must move forward with the objective of not permitting hypoxemia. At the same time, we must make every effort to avoid hyperoxia Tables 2 and 3.
We cannot forget that in clinical care we cannot see many important factors at the cellular and tissue level. Only healthcare providers can induce hyperoxia and its inherent risks. A future goal in clinical care would be to find better SpO 2 limits or different technologies that can assist clinicians in eliminating hyperoxemia and hypoxemia during the neonatal period.
Until this happens, we should change general practice, aiming to avoid hyperoxia without permitting hypoxemia. This paper was supported by a grant from Dey, L. Masimo, among other industries, has supported educational activities organized by Dr. While it all may seem overwhelming at first, you will become a pro before you know it. Contact your child's doctor or oxygen equipment provider with any questions. You may be trying to access this site from a secured browser on the server.
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Text Size. Page Content. Home oxygen delivery systems There are three main types of oxygen delivery systems used at home, including: Compressed gas. Other equipment Depending on the reason your baby needs oxygen therapy, an apnea monitor or a pulse oximeter may be used. The atmosphere of earth consists of a mixture of many gases such as nitrogen, oxygen and carbon dioxide.
Therefore the fraction of oxygen in room air is 0. This is true, both at sea level and at high altitudes, and is adequate to meet the needs of aerobic metabolism in adults and newborn infants. In South Africa kPa is the unit usually used to express partial pressure.
At this oxygen saturation the haemoglobin in arterial blood is fully loaded with oxygen. At these levels hypoxaemia the red cells will not be adequately loaded with oxygen. The infant may now appear cyanosed and the cells of the body will not receive enough oxygen for aerobic metabolism hypoxia.
Therefore, extra oxygen is needed in the inspired air i. If the cells of the body do not receive enough oxygen they can be damaged or die. Without adequate oxygen, cells are forced to change from aerobic to anaerobic metabolism. This markedly reduces the amount of energy the cells can produce.
Toxic substances, such as lactic acid, are also produced as a by-product of anaerobic metabolism. This causes a metabolic acidosis. The cells of many organs, but particularly the brain, are affected by these metabolic changes. Infants with respiratory distress due to clinical conditions such as hyaline membrane disease, pneumonia and meconium aspiration.
Extra oxygen may also be needed by some infants who require resuscitation at birth. Therefore, do not give oxygen unless it is needed. Also do not give more oxygen than is required. In an emergency, oxygen should be given for as short a time as possible. Giving oxygen can be dangerous when it is not required. This causes retinal ischaemia and haemorrhage with healing by fibrosis. This important eye problem is called retinopathy of prematurity. Mild degrees of retinopathy recover and vision is not affected.
However, severe retinopathy with a lot of fibrosis causes a condition known as retrolental fibroplasia which can permanently impair vision and even result in blindness. The lower the gestational age the greater is the risk of retinopathy of prematurity. The risk of retinopathy is greatest in infants under 32 weeks gestation. At term the risk of oxygen toxicity to the retina is much less. Retinopathy is diagnosed by examining the eye with an ophthalmoscope.
If these investigations are not available, give just enough oxygen to correct central cyanosis, i. As there are dangers in giving too much or too little oxygen, the following principles must be followed to ensure that oxygen administration is safe:. Oxygen or medical air direct from a cylinder or wall piping is very dry and cold. Oxygen and medical air should always be humidified and warmed if it is being given at high flow rates via nasal prongs or an endotracheal tube.
Warmed humidification is not necessary if oxygen and medical air is given into a head box or by nasal cannulas as a low flow is inspired through the nasal passages, where it can be warmed and humidified. Dangers of humidifiers include overheating, drowning and infection. A supply of both oxygen and medical air is needed for a blender. Oxygenation and oxygen therapy must be closely monitored.
Appropriate use is life saving but inappropriate use has dangers: i. In unwell infants, oxygen needs are continually changing and the nurse should vary the inspired oxygen concentration within these guidelines. Call medical staff for urgent assistance. Babies receiving supplemental oxygen, or those likely to need it should be monitored by continuous pulse oximetry, with the exception of babies close to being discharged on oxygen. If an arterial line is in situ , regular blood gases should be done.
The frequency of these varies with the clinical situation discuss this with medical staff or NS-ANPs. For recommended values see saturation targets above. Be careful to decrease FiO2 after a desaturation and avoid overshooting to high SpO2 levels.
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