The Mechanical and Structural Properties of Reinforcing Materials used in Prosthetic Herniorrhaphy

Three types of reinforcing material that are used in herniorrhaphy were tested by biaxial straining to obtain their load-extension properties. Steel mesh was by far the stiffest material, followed by porcine skin, then Mersilene mesh, when tested by suturing around their periphery. The Mersilene mesh and porcine skin failed around the holes made by the suture, whilst the sutures failed when used with the steel mesh.

A comparison of the direct cost of care in an open-bay and single-family room NICU

OBJECTIVE

This research examined the proposition that the direct costs of care were no different in an open-bay (OPBY) as compared with a single-family room (SFR) neonatal intensive care (NICU) environment.

STUDY DESIGN

This was a sequential cohort study.

RESULT

General linear models were implemented using clinical and cost data for all neonates admitted to the two cohorts studied. Costs were adjusted to year 2007 U.S. dollars. Models were constructed for the unadjusted regression and subsequently by adding demographic variables, treatment variables, length of respiratory support and length of stay. With the exception of the last, none were found to achieve significance. The full model had R(2)=0.799 with P=0.0095 and predicted direct costs of care less in the SFR NICU.

CONCLUSION

For the time, location and administrative practices in place, this study demonstrates that care can be provided in the SFR NICU at no additional cost as compared with OPBY NICU.

Adiabatic evolution of plasma equilibrium

A new theory of plasma equilibrium is introduced in which adiabatic constraints are specified. This leads to a mathematically nonstandard structure, as compared to the usual equilibrium theory, in which prescription of pressure and current profiles leads to an elliptic partial differential equation. Topologically complex configurations require further generalization of the concept of adiabaticity to allow irreversible mixing of plasma and magnetic flux among islands. Matching conditions across a boundary layer at the separatrix are obtained from appropriate conservation laws. Applications are made to configurations with planned islands (as in Doublet) and accidental islands (as in Tokamaks). Two-dimensional, axially symmetric, helically symmetric, and closed line equilibria are included.

Pharmacokinetics of 3-methyl-(triazen-1-yl)imidazole-4-carboximide following administration of temozolomide to patients with advanced cancer

The antitumor activity of temozolomide (TMZ) is believed to arise via formation of the reactive, alkylating metabolite 3-methyl-(triazen-1-yl)imidazole-4-carboximide (MTIC), which is produced by chemical hydrolysis of the parent drug. MTIC has not been quantitated in plasma or urine following administration of TMZ to patients. We developed a sensitive, specific method for the determination of MTIC levels in plasma, based on reverse-phase high-pressure liquid chromatography of the supernatant that is obtained by methanol precipitation of plasma proteins. Due to poor stability under physiological conditions, determination of MTIC required rapid specimen processing, precipitation of plasma proteins with methanol, and storage of the methanolic supernatant at -70 degreesC. The pharmacokinetics of MTIC were studied in 15 patients who received 125-250 mg/m2 TMZ. Peak plasma concentrations of 0.07-0.61 microgram/ml MTIC were observed approximately 1 h after a p.o. dose of TMZ. Appearance and disappearance (t1/2, 88 min) of the reactive metabolite paralleled the appearance and disappearance of TMZ in plasma. The mean values of the metabolite peak plasma concentration and AUC were 2.6% (range, 1.6-4.6%) and 2.2% (range, 0.8-3.6%), respectively, of the values for TMZ. MTIC did not accumulate in plasma following five consecutive daily doses of TMZ.

Survival of the tiny neonate: USD School of Medicine/Sioux Valley Hospital experience, 1981-1992

The survival of very low birth weight newborn infants of < or = 1000 gms cared for in the University of South Dakota School of Medicine/Sioux Valley Hospital Neonatal Intensive Care Unit was analyzed for the 12 year period of 1981-1992. Survival has increased from 45% in 1981-1983 to 65% in 1990-1992. The most recent figures for 1990-1992 indicate 54% survival in neonates of < or = 600 gms, 73% in those of 601-700 gms, 56% in those of 701-800 gms, 60% in those of 801-900 gms and 81% in those of 901-1000 gms. Survival rates by birth weight and gestational age are comparable to nationally published statistics. The potential for normal long term outcome, including physical growth and intellectual development, appears to be very good, with 74% of long term survivors having no evidence of severe physical or neurologic impairment at the time of discharge from the hospital.

Acid-base abnormalities associated with cocaine toxicity in emergency department patients

There is little information on the prevalence and clinical presentation of acid-base abnormalities associated with cocaine toxicity. To address these issues, arterial blood gas results were evaluated in 156 cocaine-associated emergency department patient visits. Arterial blood gas results were obtained as part of the patient's clinical assessment. The majority of patients (52%) had a normal pH (7.35 to 7.45). Thirty-three percent of patients were acidotic, with a pH between 6.4 and 7.35. In 33 patients the acidosis was metabolic, with a HCO3- of 14 +/- 6 mmol/L. The acidosis was primarily respiratory in 18 patients, with evidence of hypoventilation. Hypoventilation was generally secondary to chest trauma or decreased mental status. Alkalosis (pH > 7.45) was observed in 15% of patients, and was usually respiratory, as evidenced by tachypnea and a low PCO2. These results indicate that metabolic and respiratory acid-base abnormalities are common during cocaine toxicity. Acidosis and alkalosis were associated with numerous patient presentations, including chest pain, shortness of breath, decreased mental status, trauma, and seizures. Acid-base abnormalities do not appear to be associated with a specific route of cocaine self-administration. Patients with a history of potential cocaine toxicity should be evaluated for acid-base abnormalities.

Does prenatal care decrease the incidence and cost of neonatal intensive care admissions?

This study was conducted to examine the potential effects of expanded Medicaid coverage for low income women. Statewide birth data for 1983 to 1985 were examined to determine the relationship between prenatal care and admissions to neonatal intensive care units (NICUs) and the costs of this care. An NICU sample was constituted from infants who were discharged live following more than 7 NICU days, were referred to an out of state tertiary center, or died following NICU admission. Inadequate care (no prenatal care, only last trimester care, or less than five visits) was received by 11% of the total birth cohort and by 18% of the infants in the NICU sample (p less than 0.001). Infants with inadequate care had a NICU admission rate of 5.10% versus 2.86% for those with adequate prenatal care (p less than 0.001). The hospital billings for infants in the NICU sample with inadequate care were significantly higher than were those for infants with adequate care (p less than 0.05). Assuming that economic resources limit access to prenatal care, the projection can be made that had all women with inadequate prenatal care received Medicaid-covered adequate prenatal care, expenditure for this care would yield more than a two to one return in savings in NICU costs.

Mothers' behavior with home infant apnea monitors

This study presents findings from 35 interviews with mothers of infants who were monitored for apnea following discharge from the same neonatal intensive care unit. The interviews took place at a mean of 28 weeks following discontinuation of the infant home apnea monitor and focused upon the mothers' behavior with the monitor. One family had independently ceased to use the monitor within 1 week of their infant's hospital discharge. All other mothers reported always having used the monitor at night, and 92% always used it during their infants' daytime naps. Approximately one half of the mothers would not have been able to consistently hear an alarm, however, when their infant was asleep. Consistency of availability to a monitored infant was not related to the mothers' background, attitudes, or experiences with their infant. These data indicate the need to emphasize for all caregivers the importance of being available to their monitored infant at all times.

Studies of aerosol distributions in a small laboratory containing a heated phantom

In order to provide information to assist in the design and planning of workplace air-sampling facilities, we have studied the variations in time and space of aerosol concentrations in a small room containing a glove-box and a heated phantom. Aerosol concentrations are reduced by factors of 10(2)-10(3) between the source and the phantom and walls of the room. Time-series plots of concentration show large departures from mean concentrations and fluctuations measured at the mouth and chest of the phantom are frequently uncorrelated. Both the average concentration around the phantom and the fluctuations in concentration tend to increase when the phantom is heated.

The microcomputer as a clinical research tool

A microcomputer system has been developed for clinical perinatal-neonatal research. This system is composed of commercially available hardware and software that is readily available, relatively inexpensive, and easy to learn to use. Systems like this permit compilation of data, statistical analysis, and the possibility of intercommunication with other microcomputers and mainframe systems in collaborative research endeavors. Further, microcomputer systems allow investigators immediate access to data and data analysis within their own offices.

Lumbar puncture in infants

Lumbar puncture is indicated in any infant with symptoms suggestive of meningitis (seizures, intractable vomiting and unexplained fever) and in the evaluation of neonatal intracranial bleeding. The infant must be held firmly in the lateral decubitus or sitting position. Under sterile conditions, a 22- to 25-gauge needle is inserted into the L3-4 interspace. The most important complication is unrecognized compromise of respiratory status.

Endotracheal intubation of the neonate

Endotracheal intubation in the newborn may be a lifesaving procedure, a especially in cases of meconium aspiration and congenital diaphragmatic hernia. All equipment for performing intubation should be available in the delivery area. The most common and potentially serious error is leaving the endotracheal tube in the wrong position. Auscultation of the chest and abdomen must be performed and a chest x-ray obtained to document the location of the tube.

The death of a newborn twin: an analysis of parental bereavement

The emotional responses of eight families who lost a singleton newborn were compared with those of eight families who lost a twin. The mean gestational age of the babies in both groups was 31 weeks. At a mean time of 15 months following their loss, parents were sent a questionnaire which requested that they report their responses during the first six weeks following their baby's death and their present response to this experience. Embedded in the questionnaire was a 20-item depression symptom inventory. Analysis of variance indicated that although mothers experienced significantly more depressive symptoms than fathers (F = 59.48, P = .001) and that all symptoms had diminished greatly over time (F = 6.02, P = .032), there was no significant difference between the parents who had lost a twin and those who had lost a singleton. However, family, friends, and hospital staff frequently ignored or downplayed the death of the twin assuming that the grief of the parents would be minimal because of the surviving twin. Results of this study indicate that the presence of a living twin in no way lessens the grieving process and that a conscious effort needs to be made to allow parents to express openly their feelings of loss when a twin dies.

Respiratory distress following elective repeat cesarean section

The clinical course and chest radiographs of 47 infants with respiratory distress after elective cesarean section were reviewed. The mean difference between the gestational age determined prenatally and that postnatally was 2.6 +/- 1.6 weeks. However, 14 of the infants were delivered at term. All 47 infants required more than 40% oxygen, and 18 infants required a respirator. Fifteen infants developed a pneumothorax; one, a pneumopericardium; one, bronchopulmonary dysplasia; and one infant died. Chest radiographs and the clinical course were consistent with hyaline membrane disease in 17 patients; respiratory distress syndrome type II in 24; and in three the radiographic findings were normal. These data suggest that some of the respiratory morbidity subsequent to elective repeat cesarean section is not secondary to iatrogenic delivery of a premature infant, and that much of it is not due to hyaline membrane disease. These data emphasize that respiratory distress in an infant delivered by elective cesarean section does not necessarily suggest poor prenatal care in regard to the timing of delivery.

Supraventricular tachycardia with edema, ascites, and hydrops in fetal sheep

Continuous supraventricular tachycardia was induced in 13 fetal sheep for 72 to 216 hours. The PaO2 decreased from 18.1 +/- 1.2 (SEM) to 15.4 +/- 0.9 mm Hg and the PaCO2 increased from 41.5 +/- 1.2 (SEM) to 46.0 +/- 1.0 (SEM) mm Hg with pacing. The hematocrit, total protein, albumin, serum [Na+] and [K+], and osmolality remained unchanged throughout the study. All study fetuses showed signs of ascites (mean = 88 +/- 67.5 [SD] ml), and one was grossly hydropic. Six fetuses, all of which had greater than or equal to 50 ml of ascites, died as the results of pacing. Gross pathologic findings in 13 fetuses included: cardiomegaly in seven, cyanotic myocardium in two, hepatomegaly in seven, pulmonary congestion in two, generalized edema in three, and massive edema (hydrops) in one. None of these conditions was found in the 14 control animals. There was no correlation of the severity of effects upon the fetus and the induced heart rate, the duration of tachycardia, or the site of implantation of the pacemaker. The conclusion was that organomegaly, generalized edema, and hydrops fetalis were the direct result of supraventricular tachycardia in utero; the exact mechanism of production and the reasons for the variable manifestations of tachycardia remain unclear.

Dose requirement of d-tubocurarine and metocurine used for chronic respiratory paralysis in neonates

Nondepolarizing muscle relaxants are being used with increasing frequency in neonatal intensive care units. However, information concerning the chronic use of these agents and their dose requirements of d-tubocurarine and metocurine in neonates in whom respiratory paralysis was used as an adjunct to mechanical ventilation. All infants with gestational age greater than or equal to 38 wk demonstrated a dramatic daily increase in dose requirement of metocurine during the initial 8 days. However, infants with gestational age greater than or equal to 33 wk did not demonstrate a statistically significant daily increase in dose requirement. The 4 infants who received metocurine for more than 10 days exhibited a plateau of the dose requirement after 8-10 days. In contrast to the infants receiving metocurine, infants who received d-tubocurarine did not demonstrate a significant change in daily dose requirement. Four infants who received metocurine and four who received d-tubocurarine had acute renal failure and were not included in the above analysis. These infants had a significantly decreased dose requirement compared to the expected dose requirement for infants of comparable gestational age. There was no relationship between the dose requirement and the pH, serum potassium, or the use of aminoglycoside antibiotics.

An analysis of tolazoline therapy in the critically-ill neonate

There were 47 seriously-ill neonates with medical causes of respiratory distress and 10 infants with severe respiratory distress secondary to a congenital diaphragmatic hernia treated with tolazoline according to a strict protocol designed to manage persistent fetal circulation (PFC). Of the 47 infants, 28 (60%) had a positive response defined as an increase in the pO2 greater than or equal to 24 mm Hg within 4 hr of beginning the drug. Of 7 infants, 4 with congenital diaphragmatic hernia had a positive response. The mean increase in the pO2 for the 47 infants was statistically significant (p less than .05). Of the 47 infants with medical disorders, 27 survived (survival 57%), whereas only 2 of the 10 infants with congenital diaphragmatic hernia and severe persistent fetal circulation survived (survival 28%). Erythema (60%), hematest positive gastric aspirates (55%), thrombocytopenia (45%), hyponatremia (40%) and increased gastric aspirates (36%) were the most common adverse effects occurring during tolazoline infusion. Hypotension occurred in nine cases, but was transient. Of the 27 survivors, 20 with medical causes of persistent fetal circulation were evaluated at age 1 yr. Eighty percent of these infants studied were considered normal as defined by an MDI and PI of the Bayley Scales of greater than or equal to 70. These data suggest that tolazoline is a useful adjunct in the management of neonates with PFC. In addition, tolazoline was more effective in mechanically ventilated neonates treated with respiratory paralytic agents. Although tolazoline resulted in a significant improvement in the paO2 in 4 infants with congenital diaphragmatic hernia, it did not appear to improve mortality in these infants.

Respiratory paralysis to improve oxygenation and mortality in large newborn infants with respiratory distress

The nonsynchronous respiratory efforts of neonates with surgically correctable disorders may inhibit effective mechanical ventilation. The records of 25 infants treated with metocurine for muscular paralysis to improve mechanical ventilation were reviewed. All patients were greater than 35 (37.6 +/- 2.1) weeks gestation and 2.27 (2.98 +/- .47) kg. All required ventilatory support with an FiO2 of 100%. The mortality rate of this group of infants was 20% as compared with 73% (p < .001) in a similar group of 26 infants managed without paralysis. In 10 of the 25 infants treated with metocurine, pre- and 1 hr postparalysis paO2 values were available. The mean paO2 prior to paralysis was 62 (45--111) mm Hg and the mean post-paralysis paO2 was 144 (75--227) mm Hg, representing at 132% increase in paO2 (p < .001). The mean dosage for metocurine was 3.5 (1.45--6.79) mg/kg/day; however, those requiring paralysis for greater than 7 days showed a dramatically increasing requirement. These preliminary data suggest that respiratory paralysis reduces right-to-left shunting, improves paO2 and decreases mortality in large infants with severe respiratory distress requiring ventilatory support.

Increased incidence of lactobezoars in low birth weight infants

Fifteen low birth weight infants had their conditions complicated by the formation of a lactobezoar. The mean gestational age was 30.3 weeks; mean birth weight was 1,184 g, and the mean age at the time of diagnosis was 11.8 days. Twelve of the infants were receiving an 80 kcal/dL-formula and one infant, a 40 kcal/dL-formula designed for the premature infant. Symptoms included abdominal distension, emesis or increased gastric residual, diarrhea, hematest-positive stools, abdominal mass, and gastric perforation.

Fetal and neonatal ventricular arrhythmia

Ventricular arrhythmia in the perinatal period is observed with greater frequency than reported in the literature. Four cases from the authors' experience and an analysis of the literature are presented. Of the total of 45 cases, nine were detected in utero, three persisted beyond the neonatal period, and two resulted in death with associated disorders. Twenty-four percent of the entire group had serious medical disorders associated with arrhythmia; however, 43% of the group with ventricular tachycardia had major associated disease.