Automatic Oxygen Control System Improves Oxygen Delivery in Preterm Infants

By Will Boggs MD

 January 31, 2014

NEW YORK (Reuters Health) - For maintaining O2 saturation in preterm infants, an automatic oxygen control system is better than routine manual control, new research suggests.

"It is possible to improve respiratory support for preemies with new technology," Dr. Michael Siegfried Urschitz from University Medical Center of the Johannes Gutenberg University, Mainz, Germany told Reuters Health by email. "The time has come that intelligent assistant systems (like in cars) can be used by physicians to improve patient care."

Dr. Urschitz and colleagues earlier showed that automatic was better than manual care in maintaining oxygen saturation within the desired range in infants receiving nasal continuous positive airway pressure (CPAP) and in mechanically ventilated infants.

In the current study, they compared outcomes with closed-loop automatic control of the inspired oxygen vs routine manual control by nursing staff under routine conditions in three level-III NICUs, for 24 hours with each approach.

The study had to be terminated prematurely after enrollment of 34 preterm infants, according to a report January 27th online in Pediatrics.

The goal was to keep the O2 saturation within a targeted range. In every patient, the target saturation was higher during closed-loop automatic control than during routine manual control, averaging 11.1 percentage points higher (with a 2 percentage point increase deemed clinically relevant).

The percentage of time spent below the target range was lower with closed-loop automatic control, whereas the percentage of time spent above the target range did not differ between closed-loop automatic control and routine manual control.

Moreover, nurses had to make fewer manual adjustments to inspired oxygen percentage in the closed-loop automatic control period than in the routine manual control period.

Throughout the study periods, the mean target saturation levels were higher with closed-loop automatic control than with routine manual control.

"This device might help to reduce morbidity resulting from intermittent hypoxemia or large fluctuations in oxygen saturation levels, such as retinopathy of prematurity, brain injury, or other organ damage and may help to improve neurodevelopmental outcome," the researchers suggest. "Furthermore, the system may also reduce workload related to inspired oxygen control and may help to decrease the level of noise and stress for nursing staff members and patients alike."

The automated system is more costly. "The difference is about 1000" - about US$1350 - "but pricing is not finished," Dr. Urschitz said.

Dr. Fleur Tehrani from California State University in Fullerton has studied systems like the one used for automatic control in this study. Dr. Tehrani told Reuters Health by email, "Automatic closed-loop systems can help physicians in controlling ventilation parameters more effectively and save costs, too."

"In manual control, FiO2 is adjusted by the medical personnel by measuring either arterial oxygen pressure values or arterial oxygen saturation," Dr. Tehrani explained. "In the automatic mode, such data is analyzed by a computer and FiO2 is adjusted automatically by the computer."

"The system that these authors have used was first introduced in 1999," Dr. Tehrani explained. "Its main disadvantage is that it cannot respond to acute hypoxic episodes. There have been other computerized methods that can respond more effectively and robustly to hypoxia."

Dr. Nelson Claure heads the Neonatal Pulmonary Research Laboratory at University of Miami Miller School of Medicine, Miami, Florida, where he co-developed and patented an algorithm for automatic FiO2 control that was built into the ventilator that was used in their studies. He told Reuters Health by email, "Under routine clinical conditions premature infants spend considerable periods of time outside the clinician's intended target range of arterial oxygen saturation. Systems for automatic FiO2 control are likely to increase the time these infants spend within these ranges."

"Studies that evaluated automatic FiO2 control in premature infants, including the one recently published and those published previously, have shown promising results in regards to the maintenance of arterial oxygen levels within a targeted range, reduction in hyperoxemia and episodes of severe hypoxemia," Dr. Faure said. "These studies also showed reduced exposure to supplemental oxygen and staff workload. There are at this time ongoing studies to further confirm these findings."

"At present time there are no data on the impact of extended use of automatic FiO2 control on morbidities such as retinopathy of prematurity and bronchopulmonary dysplasia in the premature infant population that are influenced by excessive oxygen administration or insufficient/fluctuating oxygen levels," Dr. Faure said. "This evidence, that can be obtained in clinical trials, is likely to influence the adoption of this technique."