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Biomedical subjects

T E Wiswell

Publications and source records attributed to T E Wiswell.

At least 55 records · Page 3Linked to original sources
PubMed1991

Multiple site blood cultures in the initial evaluation for neonatal sepsis during the first week of life.

We present the first investigation that examines the usefulness of multiple site blood cultures in the initial evaluation for neonatal sepsis during the first week of life. Two sets of blood cultures (1 aerobic and 1 anaerobic bottle/set; BACTEC, NR 6A/7A) from different sites were obtained from 460 inborn infants who were evaluated for possible sepsis. From 0.5 to 1 ml of blood was inoculated into each blood culture bottle. In 18 infants the use of multiple site blood cultures yielded important information. In 8 of these neonates bacteremia was confirmed whereas in 10 cases contamination from skin flora was documented. We could identify no instances in which the delay in antibiotic therapy while the second set of blood cultures was obtained contributed to an adverse outcome. We conclude that multiple site blood cultures are useful in the initial evaluation for suspected sepsis during the first week of life.

Bacterial Infections↗
PubMed1990

Major congenital neurologic malformations. A 17-year survey.

We present characteristics of four major congenital neurologic malformations--anencephaly, spina bifida, encephaloceles, and hydrocephalus--from a population of 763, 364 live-born and still-born infants born from 1971 through 1987. During the 17-year study period, 275 infants had anencephaly (0.36 per 1000 total births), 526 had spina bifida (0.69 per 1000 total births), 112 had encephaloceles (0.15 per 1000 total births), and 370 had hydrocephalus (0.48 per 1000 total births). There was a female preponderance of infants with anencephaly, spina bifida, and encephaloceles, while males predominated among those with hydrocephalus. We found declining incidences of anencephaly, spina bifida, and encephaloceles only among white females. Black infants were significantly less likely than white infants or infants of other races to have spina bifida. Twenty percent of infants with anencephaly had congenital anomalies unrelated to the primary defect, as did 40% with encephaloceles, 37% with hydrocephalus, and 22% with spina bifida. Because the racial background of the patient population closely resembles that of the United States as a whole, the features of the malformations described may reflect those of the country.

Anencephaly↗
PubMed1990

The effect of 100% oxygen on the propagation of tracheobronchial injury during high-frequency and conventional mechanical ventilation.

We compared the histologic alterations in the tracheae and bronchi of 30 premature baboons that were ventilated with either 100% or prn (as needed) oxygen (the fraction of inspired oxygen necessary to maintain the PaO2 between 50 and 80 mm Hg). The baboons were treated with either conventional positive-pressure ventilation (7 were treated with 100%; 7, prn) or high-frequency oscillatory ventilation (8 were treated with 100%; 8, prn). We used a semiquantitative scoring system to grade tissue changes in the trachea, carina, and main-stem bronchi. The fraction of inspired oxygen for all prn animals fell to a plateau of approximately 0.28 after 36 hours, where it remained for the duration of the study. The 15 100% baboons were ventilated for a mean of 139 hours, while the 15 prn baboons were ventilated for a mean of 151 hours. The findings in all conventional and oscillator-ventilated animals were similar and characterized by squamous metaplasia, cilia loss, and goblet cell loss. For both methods of ventilation, there were no differences in the injury scores between 100% and prn oxygen-treated animals. We concluded that there were no additional tracheobronchial histologic changes with 100% oxygen compared with prn oxygen.

Animals↗
PubMed1990

Acrofacial dysostosis with ambiguous genitalia.

We report on a 46,XY infant with mandibulofacial dysostosis, preaxial and postaxial limb anomalies, urethral stenosis with left hydronephrosis, and ambiguous genitalia with phallic/scrotal transposition. This infant with atypical pre/postaxial acrofacial dysostosis (AFD) is the first to be reported with ambiguous genitalia. The acrofacial dysostoses are a heterogenous group of disorders characterized by varying degrees of mandibulofacial dysostosis with acral limb defects and may represent a polytopic field defect. These disorders have generally been separated on the basis of their limb anomalies into preaxial, postaxial, lethal, and atypical types. Most cases are sporadic, but various causes have been postulated including autosomal dominant and recessive inheritance, a chromosome 2q duplication, and a possible case of diabetic embryopathy. We review the nonfacial/limb anomalies in other cases of AFD and compare them to those of our case, thereby expanding the spectrum of anomalies in these disorders.

Abnormalities, Multiple↗
PubMed1990

Management of asymptomatic, term gestation neonates born to mothers treated with intrapartum antibiotics.

Intrapartum antibiotics are frequently administered to parturient women for suspected chorioamnionitis to treat infection in the mother and to prevent or treat infection in the baby. We sent a questionnaire to the 150 United States fellowship program directors in neonatology and pediatric infectious disease, focusing on recommendations for evaluation and therapy of apparently healthy, pretreated, term gestation infants. Eighty-three (55%) of the completed responses were analyzed. Sixteen (19%) respondents do no initial laboratory evaluation but simply observe the baby, 65 (78%) take a complete blood count as well as a platelet count, 59 (71%) obtain blood cultures, 41 (49%) check urine antigen for Group B Streptococcus (GBS) and 23 (28%) perform a lumbar puncture. Only 39% of respondents would begin antibiotic therapy for all pretreated infants. If the evaluation were unremarkable 65 directors would treat for less than or equal to 3 days. If only the urine GBS antigen were positive 47 would treat for greater than or equal to 7 days, while if an elevated immature neutrophil:total neutrophil ratio were the sole abnormality 19 would treat for greater than or equal to 7 days. Forty-four respondents thought that a combination of an elevated immature neutrophil:total neutrophil ratio and a positive urine GBS antigen should always be considered indicative of bacteremia. Given a different scenario, that of a mother treated with intrapartum antibiotics because of a positive cervical culture for GBS and a risk factor (e.g. temperature greater than or equal to 38 degrees C), 58 respondents would begin antibiotics. There is no consensus regarding management of pretreated, healthy appearing, term gestation neonates.

Anti-Bacterial Agents↗
PubMed1990

Different high-frequency ventilator strategies: effect on the propagation of tracheobronchial histopathologic changes.

To assess the role of high-frequency ventilator strategy in the propagation of airway injury, we compared the tracheobronchial histologic alterations in 20 newborn piglets ventilated for 8 hours with high-frequency flow interruption (HFFI). Ten animals were assigned to HFFI with a strategy of continuous pulsations at a frequency of 10 Hz and a mean airway pressure of 16 cm H2O. Ten piglets were treated at identical settings except for 10 one-second baseline pauses per minute to a positive end-expiratory pressure of 5 cm H2O. A semiquantitative scoring system was used to grade light microscopic tissue alterations in the trachea, carina, and mainstem bronchi. Ultrastructural changes were evaluated with scanning electron microscopy. The HFFI-continuous-treated piglets had significantly more damage in all areas than the HFFI-baseline pause group (P less than .001). The upper tracheas of animals in both groups were altered to a greater extent than the lower tracheas (P less than .007). In addition, numerous "skip" areas of injury were noted throughout the tracheas. High-frequency ventilator strategy is a determinant of the severity of airway histologic changes. Factors that adversely affect tissue oxygenation or cause direct mechanical trauma may also influence the degree of injury. Optimal operating characteristics and limitations of different high-frequency devices must be assessed before their use in human neonates.

Animals↗
PubMed1990

Meconium aspiration syndrome: have we made a difference?

Meconium aspiration syndrome (MAS) and its associated complications are reviewed from the period before the routine use of intubation and suctioning to the present (1973 through 1987). Of the 176,790 neonates born during this period, the amniotic fluid was stained in 21,472 (12.15%). Subsequently, MAS developed in 1162 (5.41%) of the meconium-stained neonates. Male neonates were more prone to the disorder than female neonates (P = .022). There were no racial predilections for MAS. The incidence of MAS significantly decreased during the 15 years (P = .043). Of the neonates with MAS, 49 (4.22%) died as a direct consequence of the disorder. The death rate significantly declined during the study period (P = .041). Of the neonates with MAS, 345 (29.7%) required mechanical ventilation, and 134 (11.53%) had pneumothoraxes. Among neonates with MAS, the requirement for mechanical ventilation, as well as the incidence of pneumothoraxes, did not decrease from 1973 through 1987. The incidence of MAS has declined since the advent of combined obstetric and pediatric suctioning of the oropharynx and trachea. Furthermore, there are significantly fewer deaths from the disorder. These declines were likely influenced by other improvements in perinatal care, which have occurred since the early 1970s. The results do not support the contention that severe MAS and resultant deaths can be prevented altogether.

Apgar Score↗
PubMed1990

Circumcision.

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Circumcision, Male↗
PubMed1990

Routine neonatal circumcision: a reappraisal.

Routine neonatal circumcision has long been a controversial subject. The American Academy of Pediatrics has recently outlined a new position on circumcision that is a marked departure from its previous stance. Neonatal circumcision has many potential advantages: The procedure helps prevent urinary tract infections, penile cancer, sexually transmitted diseases and, perhaps, acquired immunodeficiency syndrome. The risk of complications from the procedure is low. Fewer penile problems occur in circumcised boys than in uncircumcised boys. It is more economical to perform the procedure early in life, rather than later. No evidence shows that penile hygiene alone is as beneficial as circumcision.

Circumcision, Male↗
PubMed1989

Malignant hyperthermia in infancy.

We have described two infants, aged 2 months and 5 months, who had malignant hyperthermia, an entity not generally believed to occur during infancy. Both children were under general anesthesia when MH occurred, and both responded well to administration of dantrolene and sodium bicarbonate.

Colonic Diseases↗
PubMed1989

Risks from circumcision during the first month of life compared with those for uncircumcised boys.

The records of 136,086 boys born in US Army hospitals from 1980 to 1985 were reviewed for indexed complications related to circumcision status during the first month of life. For 100,157 circumcised boys, there were 193 complications (0.19%). These included 62 local infections, eight cases of bacteremia, 83 incidences of hemorrhage (31 requiring ligature and three requiring transfusion), 25 instances of surgical trauma, and 20 urinary tract infections. There were no deaths or reported losses of the glans or entire penis. By contrast, the complications in the 35,929 uncircumcised infants were all related to urinary tract infections. Of the 88 boys with such infections (0.24%), 32 had concomitant bacteremia, three had meningitis, two had renal failure, and two died. The frequencies of urinary tract infection (P less than .0001) and bacteremia (P less than .0002) were significantly higher in the uncircumcised boys. Serious complications from routine prepuce removal are rare and relatively minor. Circumcision may be beneficial in reducing the occurrence of urinary tract infections and their associated sequelae.

Circumcision, Male↗
PubMed1989

Determinants of tracheobronchial histologic alterations during conventional mechanical ventilation.

It was hypothesized that diverse mechanisms may influence upper airway injury during mechanical ventilation. To assess the roles of several factors in the propagation of such injury, the tracheobronchial histologic changes in 53 newborn piglets were compared following conventional positive pressure ventilation. Eight animals were assigned to each of four positive pressure ventilation groups at "low" settings (an FiO2 of 0.25, a frequency of 10 breaths per minute, a peak inspiratory pressure of 20 cm H2O, a positive end-expiratory pressure of 4 cm H2O, a flow rate of 10 L/min, and an inspiratory time to expiratory time ratio of 1:2): (1) positive pressure ventilation with no hypotension or hypoxemia; (2) positive pressure ventilation with hypotension; (3) positive pressure ventilation with hypoxemia; and (4) positive pressure ventilation with both hypotension and hypoxemia. In addition, eight piglets were assigned to each of two positive pressure ventilation groups at "high" settings (greater frequency [40 breaths per minute], higher peak inspiratory pressure [40 cm H2O], and greater flow rate [17 L/min]): (1) positive pressure ventilation with no hypotension or hypoxemia; and (2) positive pressure ventilation with both hypotension and hypoxemia. The changes were mild and similar among the first three positive pressure groups at low settings. However, the injury scores of the combined hypotension and hypoxemia group (group 4) were greater than those of the former three positive pressure ventilation groups (P less than .004). The piglets receiving positive pressure ventilation at high settings with no hypotension or hypoxemia (group 5) had no more injury than those in the first three groups receiving positive pressure ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Necrotizing enterocolitis in full-term infants. A case-control study.

We performed a case-control investigation of 43 full-term infants with necrotizing enterocolitis (NEC) to identify possible risk factors and unique features of the disorder in the more mature infant. Two control groups were used. The first consisted of "healthy" term infants. The second was a group of "sick" term infants who did not develop NEC. The 43 term infants with NEC represented 12.7% of all 338 neonates with NEC. The median age at onset of symptoms was 2 days, and 18 infants developed NEC on the first day of life. Two (4.7%) of the 43 affected term infants died, while 35 (11.9%) of 295 preterm infants with the disorder died. Only three of the full-term infants who subsequently developed NEC had entirely unremarkable courses prior to the onset of symptoms. Sick infants, in particular those who are small for gestational age or require exchange transfusions, are at risk for NEC. Several other features that may be associated with the subsequent development of NEC include the following: perinatal asphyxia, presence of umbilical catheters, antecedent respiratory distress, polycythemia, and maternal preeclampsia. Full-term infants with these features should be treated with cautious observation and aggressive management early in the neonatal period should they develop signs and symptoms suggestive of NEC.

Enterocolitis, Pseudomembranous↗
PubMed1988

Twins and triplets with necrotizing enterocolitis.

We reviewed 2856 multiple-gestation pregnancies from 1980 to 1985 to identify whether birth order or other features (eg, asphyxia) were significant risk factors for the development of necrotizing enterocolitis (NEC). There were 42 infants identified as having NEC from 30 pairs of twins and three sets of triplets. The firstborn was diagnosed with NEC in 19 (45%) of the cases, with the disorder occurring in the secondborn in 23 cases (55%). While infants A and B were simultaneously affected in nine cases, among the three sets of triplets, no thirdborn infants developed NEC. Although the secondborn infants had significantly lower one-minute Apgar scores and a more frequent need for resuscitation, they were no more prone to develop NEC than were firstborn infants. Multiple gestation, birth order, feeding practices, and a number of other features we evaluated were not associated with the development of NEC. Our findings support the contention that prematurity is the only consistent risk factor in the development of NEC.

Birth Order↗
PubMed1988

Influence of ventilatory technique on pulmonary baroinjury in baboons with hyaline membrane disease.

To assess the influence of ventilatory technique on pulmonary baroinjury in experimental hyaline membrane disease, we randomized 24 premature baboons to six treatment groups according to ventilator (PPV, positive pressure ventilator; HFO, high frequency oscillator; HFI, high frequency flow interrupter) and O2 therapy FIO2 as clinically indicated, or FIO2 1.0). PaCO2 was adjusted by varying pressure amplitude, and for PPV, also by rate (less than 60/min). HFO and HFI were set at a frequency of 10 Hz. Animals were cared for with standard NICU techniques until death or sacrifice at 11 days. One animal died at delivery and was excluded from data analysis. There were no intergroup differences in Paw, Pa/AO2, PaCO2 or oxygenation index (IO2 = [Pa/AO2]/Paw) prior to death of the first study animal at 13 h. Animals who subsequently developed airleak had higher Paw, lower Pa/AO2 and lower IO2 during this period. The degree of airleak was significantly less with HFO compared to PPV or HFI. The effect of O2 exposure did not appear different with respect to the degree of airleak or the frequency of severe tracheal injury, although survival was shortened. Severe tracheal injury was more frequent with HFI compared to PPV or HFO. BPD was found only in 100% O2 exposed animals surviving greater than 1 wk. Management of premature baboons with HFO and appropriate O2 resulted in less severe airleak, 100% survival, and no evidence of severe tracheal injury or BPD. These outcomes were not achieved with clinically similar strategies using PPV or HFI.

Animals↗