Closed-loop control of the partial pressure of arterial oxygen in neonates.

A closed-loop control system has been developed to regulate automatically the partial pressure of arterial oxygen (PaO2) to a pre-set level in neonates with RDS (Respiratory Distress Syndrome). A microcomputer-based system is described which uses the PaO2 value from an indwelling umbilical artery electrode as the input to a robust control algorithm. The derived control signal is used to modify the position of a motor driven oxygen/air blender, thus regulating the percentage of oxygen delivered in the inspired gas mixture. The parameters of the control algorithm were conservatively chosen, and the safety aspects of the system are discussed. A total of 48 h of closed-loop control were recorded on seven pre-term infants with mild-to-moderate RDS being nursed in headboxes. Ten separate closed-loop control intervals were recorded, and overall the results showed a marked improvement over comparable periods of manual control. The percentage of time for which the recorded PaO2 was within +/- 1 kPa of the chosen target value (10 kPa) was 74.9 +/- 10.2% when averaged over the ten closed-loop control periods. The corresponding figure for the comparable manual control intervals was 45.2 +/- 16.0%.

[1]  E. Reynolds,et al.  CONTINUOUS MONITORING OF ARTERIAL OXYGEN TENSION USING A CATHETER-TIP POLAROGRAPHIC ELECTRODE IN INFANTS , 1975, Pediatric Research.

[3]  P. Rolfe,et al.  Electrochemical aspects of intravascular oxygen transducers. , 1984, Journal of biomedical engineering.

[4]  Karl Johan Åström.  Adaptive Control: Fundamental Problems , 1987 .

[5]  E. Reynolds,et al.  Comparison of transcutaneous oxygen tension with arterial oxygen tension in newborn infants with severe respiratory illnesses. , 1978, Pediatrics.

[6]  Y Kawakami,et al.  A control system for arterial blood gases. , 1981, Journal of applied physiology: respiratory, environmental and exercise physiology.

[7]  J D Horgan,et al.  Pulmonary to arterial circulatory transfer function: importance in respiratory control. , 1966, Journal of applied physiology.

[8]  E. Davison.  The robust control of a servomechanism problem for linear time-invariant multivariable systems , 1976 .

[9]  J. Nunn,et al.  A reassessment of the validity of the iso-shunt graph. , 1984, British journal of anaesthesia.

[10]  J. M. Gupta,et al.  Changes in blood gas tensions following administration of amine buffer THAM to infants with respiratory distress syndrome. , 1967, Archives of disease in childhood.

[11]  J F Nunn,et al.  The use of iso-shunt lines for control of oxygen therapy. , 1973, British journal of anaesthesia.

[12]  M. Neuman,et al.  The neonatal oxycardiorespirogram. , 1984, Critical reviews in biomedical engineering.

[13]  H. Bucher,et al.  Transcutaneous PO2 monitoring in routine management of infants and children with cardiorespiratory problems. , 1976, Pediatrics.

[14]  A. J. Bart,et al.  Mathematical analysis and digital simulation of the respiratory control system. , 1967, Journal of applied physiology.

[15]  S. Godfrey,et al.  New technique for servo-control of arterial oxygen tension in preterm infants. , 1979, Archives of disease in childhood.

[16]  A. Fanaroff,et al.  Efficacy of computer-assisted management of respiratory failure in neonates. , 1986, Pediatrics.

[17]  O. Linderkamp,et al.  In Vivo vs. In Vitro Response Time of Trancutaneous Po2 Electrodes A comparison of four devices in newborn infants , 1978, Acta anaesthesiologica Scandinavica. Supplementum.

[18]  Karl Johan Åström.  A robust sampled regulator for stable systems with monotone step responses , 1980, Autom..

[19]  V. Yu,et al.  Retrolental fibroplasia--controlled study of 4 years' experience in a neonatal intensive care unit. , 1982, Archives of disease in childhood.