PubMed Health⌕ Search

Biomedical subjects

J F Lucey

Publications and source records attributed to J F Lucey.

At least 55 records · Page 3Linked to original sources
PubMed1980

Excessive handling as a cause of hypoxemia.

Continuous transcutaneous oxygen (TcPo2) monitoring was used to study low-birth-weight infants (15 control, 15 experimental) during their stay in the intensive care nursery (ICN). Twenty hours of continuous recordings were made of heart rate, respiratory rate, and TcPo2 in the first five days after birth. Personnel caring for the control infants were blind to the TcPo2 measurements. Those caring for the experimental group were instructed in the operation of the TcPo2 monitor and used the device to modify the timing and extent of procedures to minimize "undersirable time" (TcPo2 less than 40 or greater than 100 torr). Control group infants had an average of 40 min/20 hr in "undesirable time." When personnel used TcPo2 monitoring to modify care this "undesirable time" was reduced to 6 min/20 hr. This difference was statistically significant (P less than .001). Infants in the control group were handled more frequently, and experienced more hypoxemia. Of the hypoxemic time suffered by the control infants 75% was associated with handling. Only 5% of the hypoxemia or hyperoxemia was detected by blood Pao2 analysis or conventional monitors. Intermittent arterial blood gas sampling is an inadequate method for monitoring arterial oxygenation in low-birth-weight infants since hypoxemia and hyperoxemia are often missed. Continuous TcPo2 monitoring improves care by diminishing "undesirable time."

Critical Care↗
PubMed1980

Effect of application force on noninvasive measurements of intracranial pressure.

Application of the Ladd fiberoptic sensor to the anterior fontanel of the human newborn has been used as a method for monitoring intracranial pressure noninvasively. This study measures the effect of varying the force with which the sensor is applied to the fontanel. The Ladd sensor readings of five preterm human infants were continuously monitored while sensor application force was increased in a stepwise manner. The Ladd sensor readings for each infant varied with the force applied. In one infant sensor application was gradually increased while direct measurements of lumbar CSF pressure were made. Ladd sensor readings in this infant increased with increasing application force, while lumbar CSF pressure remained unchanged. It is concluded that readings obtained with the Ladd sensor applied to the anterior fontanel of the human infant depend on the force with which the sensor is applied. The effect of application force must be taken into account if noninvasive measurements of intracranial pressure are to be made with the Ladd device.

Humans↗
PubMed1980

Ultrasound detection of changing ventricular size in posthemorrhagic hydrocephalus.

Real time ultrasonography has been used to follow sequentially the changing size of the cerebral ventricles in an infant with posthemorrhagic hydrocephalus. A method for quantitating ventricular size is presented and the rapidity with which ventricular size decreases following removal of cerebrospinal fluid is demonstrated.

Cerebral Hemorrhage↗
PubMed1980

The newborn oxygram: automated processing of transcutaneous oxygen data.

Hypoxemic and hyperoxemic episodes are common in newborns with respiratory disorders. We have developed a microprocessor-based data system for use with transcutaneous oxygen (TcPO2) monitors in an attempt to quantitate these episodes. The amount of time spent by an infant in each of ten preset TcPO2 ranges can be automatically recorded. These data are referred to as the oxygram. Fourteen newborn infants were monitored for a total of 552 hours using this system. They spent a mean of 2.96% of the time with a TcPO2 less than or equal to 40 torr and 0.26% of the time with a TcPO2 greater than 100 torr. Representative oxygrams are presented. Clinical and research applications of the data system are discussed.

Humans↗
PubMed1979

Failure of conventional monitoring to detect apnea resulting in hypoxemia.

In summary, our findings support and confirm the concerns of many investigators that present methods of cardiorespiratory monitoring are inadequate for the detection of many forms of apnea. Nurses underrecord both the frequency and duration of apneic episodes. Bradycardia is an unreliable index of hypoxemia. Thoracic impedance monitors are unreliable because they detect only a fixed duration of respiratory pause and are sensitive to many artifacts unavoidable in a clinical setting. Finally, ineffective breathing patterns such as disorganized breathing, obstructive apnea, and paradoxical breathing are undetectable by thoracic impedance monitoring. We warn against the reliance on heart rate and thoracic impedance monitoring alone for infants with recurrent apnea.

Apnea↗
PubMed1978

Clinical limitations and advantages of transcutaneous oxygen electrodes.

We investigated the clinical use and limitations of the transcutaneous oxygen electrode described by Huch, Lübbers and Huch in 30 sick infants. One hundred and fifty-nine measurements of arterial oxygen tension (PaO2) and transcutaneous oxygen tension (tcPO2) were made. During the comparisons, arterial blood pressures, heart rate thoracic impedance were continuously recorded, skin axillary and environmental temperatures, hematocrit and skin thickness were measureed and the degree of peripheral perfusion noted. Despite a wide range of these variables, values of tcPO2 and PaO2 were similar (slope 0.963). Two groups of infants were identified in whom tcPO2 was lower than PaO2. These were infants receiving an intravascular infusion of tolazoline and infants with mean arterial blood pressures more than 2.5 s.d. below the predicted average value. Both of these situations represent extreme alterations in peripheral blood flow and give important information regarding the limitations of the method. Less extreme alterations in flow caused by mild hypotension, hypothermia, anemia, radiant warmers, and bilirubin lights did not adversely affect the transcutaneous PO2--arterial PO2 correlation. Advantages of transcutaneous oxygen monitoring over more conventional monitoring methods were assessed. We conclude that the transcutaneous oxygen electrode is safe, is easy to use, has few limitations and provides data which can help improve the management of most sick infants.

Blood Gas Analysis↗
PubMed1978

Transcutaneous oxygen monitoring in aminophylline-treated apneic infants.

Transcutaneous PO2 (tcPO2) monitoring offers a new approach to the evaluation of drug effects. We investigated the effect of theophylline on ten premature infants with apnea. Theophylline was administered as aminophylline, 8 mg/kg per rectum every 12 hours for two doses and 4 mg/kg every 12 hours for a total of two or five days (short and long courses). The tcPO2, heart rate (beat-to-beat), and thoracic impedance were continuously monitored during each of three 4-hour study periods: 12 hours before theophylline administration, 12 hours after initiation of theophylline therapy, and 24 to 48 hours after discontinuing the drug's use. Plasma levels were measured by a radioimmunoassay developed in our laboratory. Polygraphic recordings were analyzed without knowledge of treatment for frequency of apneic spells, mean duration of apneas, total duration of hypoxemia (tcPO2 less than or equal to 40 torr), total duration of hyperoxemia (tcPO2 greater than or equal to 100 torr), basal tcPO2, heart rate, and respiratory rate. In each case during theophylline use, cardiorespiratory patterns were altered, respirations were more regular, apneic spells were reduced, PO2 was stabilized with less hypoxia and hyperoxia, and bradycardic episodes were decreased. There was considerable variation in the response of the ten infants and a significant difference in the frequency of return of symptoms between those receiving short-term therapy and those receiving the longer course.

Aminophylline↗