Directly observed therapy in an inner city hospital.

SETTING: A directly observed therapy (DOT) tuberculosis (TB) program in a large urban teaching hospital in the East Harlem section of New York City. OBJECTIVE: In response to an emergent epidemic of TB, the State Department of Health mobilized a coalition of providers outside the public sector to provide DOT and medical care for people with TB, with the goal of treatment until cure. The results of the first 150 patients of one program are reviewed. DESIGN: A multidisciplinary DOT team coordinated treatment at several sites within and without the institution, according to established medical regimens. RESULTS: The program served a hard-to-reach population, 63% human immunodeficiency virus (HIV) positive, 64% substance users, 17% inadequately housed and 15% indigent. In the program's first three years there was 85% overall compliance with DOT visits. Using the completion of therapy index, 66% of patients completed therapy, 13% remained on treatment, 7% transferred to self medication and 1% were lost to follow up. No patient on DOT developed a drug resistant organism. There were no hospital readmissions for TB. CONCLUSION: The experience of this program demonstrates the efficacy of an intensive, personalized DOT program in ensuring treatment until cure.

Safe and effective use of transcutaneous blood gas monitors.

The Medical Devices Amendments of 1976 (PL 94-295) will compel users of transcutaneous monitors to comply with Class II, Performance Standards. These standards will have to provide reasonable assurance of the safety and effectiveness of the device. Similar standards are in preparation for other cardiac and respiratory monitors. Dangers of tcPO2 monitors include shock and burn, which requires attention to the insulation of the monitor from the power line and from recorders used to record the output. Optimal safe time vs. temperature limits have not yet used to record to output. Optimal safe time vs. temperature limits have not yet been established, and these may vary with age, skin site, blood pressure and body and environmental temperature. The usefulness of alarms for PO2, sensor temperature and heating power, and their limits remain ot be defined by extensive clinical use. Standards for drift, reproducibility, recalibration interval and accuracy will have to be set after more extensive clinical use especially by groups not involved in the initial prototype development and testing. In order to prove that these devices are also effective, physicians will have to document that care would have been different, and might have impaired patient safety, if the device had not been used.

Transcutaneous bilirubinometry. I. Correlations in term infants.

The transcutaneous bilirubinometer was evaluated in 43 white infants, eight black infants, and in nine white infants treated with phototherapy. The reproducibility of the instruments was determined after trials consisting of both five and 100 repetitions. Among the infants not being treated with phototherapy, TcB index and serum bilirubin concentration correlated at 0.90 level in both white and black infants. Phototherapy reduced the accuracy of the TcB and, at the present time, the use of this index in infants under light therapy cannot be recommended. Otherwise the TcB is a valuable tool in screening healthy term infants for hyperbilirubinemia.

Transcutaneous bilirubinometry. The cephalocaudal progression of dermal icterus.

The transcutaneous bilirubinometer (TcB) was used to document the cephalocaudal progression of dermal icterus in neonates. The TcB index of a specific area was compared with that of the forehead (TcB ratio). Four surface regions were identified, placed in the following sequence with respect to decreasing TcB ratio values: (1) forehead and sternum; (2) elbow, upper part of the back, and upper part of the abdomen; (3) lower part of the back and knee; and (4) palm and sole. To examine the relationship of the skin region of different serum bilirubin levels, a model was created that allowed the correlation of the TcB index with the specific region's distance from the forehead. Area differences in TcB values at lower bilirubin concentrations were less marked than at high levels. While the mechanism of this phenomenon has not been elucidated, the role of biophysical properties of the skin remains to be explored.

Intermediate phototherapy in the treatment of jaundice in the premature infant.

A controlled trial of the use of intermittent phototherapy for the treatment of hyperbilirubinemia in newborn infants is reported. Periods of illumination of (1) 15 minutes light on, 15 minutes light off, (2) 15 minutes on, 30 minutes off, and (3) 15 minutes on, 60 minutes off are as effective as is continuous illumunation. A comparison with previous trials of intermittent phototherapy is made and differences in results are explained using as a model the action of light on bilirubin.

Continuous monitoring of PO2 during apnea of prematurity.

We studied the changes in PO2 during 72 isolated episodes of apnea of prematurity in 20 low-birth-weight infants. A stable PO2 prior to the onset of apnea was observed in 65% of the episodes. A falling PO2 was noted in only 18% of the cases. The mean initial PO2 was 75 mm Hg and no infant was hypoxic (PO2less than 40 mm Hg) immediately prior to apnea. The mean PO2 fell to 60 mm Hg at the end of apnea and continued to fall to a mean low PO2 of 46 mm Hg. The mean PO2 at recovery was 79 mm Hg. We concluded that in this group of premature infants, hypoxia is not the initiating even in the apnea of prematurity. Furthermore, we noted that arterial oxygen tension continues to fall despite the reestablishment of respiratory efforts, that the rate of recovery from apnea is slower than the rate of fall, and that bradycardia associated with apnea is not initiated by hypoxemia.

The relationship of fetal heart rate patterns to the fetal transcutaneous PO2.

Continuous transcutaneous PO2 (tcPO2) monitoring of the human fetus was performed during 46 labors, 30 of which were complicated by abnormal fetal heart rate (FHR) patterns. FHR variability decreased with increases in the fetal tcPO2, and FHR variability increased with decreases in the fetal tcPO2. Analysis of the tcPO2 and FHR tracings provided an explanation for this apparent discrepancy. While rising fetal tcPO2 values were usually associated with decreased FHR variability, the pattern of late deceleration and decreased variability must still be considered an ominous pattern. The fetal tcPO2 declined during the deceleration and rose thereafter, with corresponding decreased FHR variability. Incomplete recovery of the fetal tcPO2 was associated with progressive acidosis. Repetitive and isolated late deceleration patterns showed markedly dissimilar fetal tcPO2 changes, suggesting different mechanisms may be involved in their production. Further studies are required before any definite conclusions can be drawn about the relationship of the FHR and the fetal tcPO2.

Umbilical vein occlusion and transient acceleration of the fetal heart rate. Experimental observations in subhuman primates.

Transient acceleration of the fetal heart rate is commonly seen in the cardiotachometer tracing of the human fetus during labor. A likely cause appeared to be partial occlusion of the umbilical cord. On the basis of this hypothesis, fetal cardiovascular responses to partial occlusion of the umbilical cord or isolated intra-abdominal portion of umbilical vein were studied in near-term pregnant baboons and rhesus monkeys prior to and following sympathetic blockade with dibenzyline and propranolol. The responses were of two types. In the well-oxygenated fetus, partial occlusion resulted in transient acceleration of heart rate and a decrease in pulse pressure. This response was abolished with dibenzyline or propranolol. In the hypoxic fetus, partial occlusion resulted in either bradycardia and hypotension or hypotension with no alteration in heart rate. Thus, transient acceleration of the fetal heart rate can be explained on the basis of a sympathetic response to diminished venous return. It would appear to be an early sign of a potential cord complication. This response will not be seen if the fetus becomes asphyxiated and hypoxic.