Comparison of the microbial barrier properties of a needleless and a conventional needle-based intravenous access system.

BACKGROUND: Sporadic reports of increased infection rates involving concerning access systems, especially in home-care setting, have raised questions concerning the safety of all needleless systems. Addressing this concern, Baxter Healthcare Corporation and the Centers for Disease Control an d Prevention performed parallel laboratory studies comparing the microbial barrier properties of the Interlink (trademark of Baxter Healthcare Corporation, Deerfield, Ill) needleless system with a conventional intravenous access system. METHODS: Studies of needleless and conventional systems evaluated fluid path contamination introduced through injection site septa, which were intentionally inoculated with high levels of bacteria and subsequently punctured with a without alcohol swabbing disinfection before access. RESULTS: With disinfection, the combined effects of the disinfection technique and the barrier properties of the septa prevented the transfer of organisms into the fluid path in 94% to 96% of needleless test articles and 96% to 100% of conventional test articles. Without disinfection, the barrier properties of the septa alone prevented the transfer of organisms into the fluid path in 20% to 69% of needleless test article and 10% to 28% of conventional test articles. CONCLUSIONS: The data demonstrate the needless system performs as well as the conventional intravenous access system with respect to the risk of microbial contamination and reinforce the need for appropriate septum disinfection before accessing either system.

Meconium obstruction in markedly premature infant.

Markedly premature infants may present with intestinal obstruction and perforation secondary to inspissated meconium in the absence of cystic fibrosis. Between 1990 and 1994, 13 patients were treated for intestinal obstruction secondary to inspissated meconium. The average birth weight was 760 g. Prenatal and postnatal risk factors were identified, and included intrauterine growth retardation, maternal hypertension, prolonged administration of tocolytics, patent ductus arteriosus, hyaline membrane disease, and intraventricular hemorrhage. Stooling was absent or infrequent during the first 2 weeks of life. Surgical presentation consisted of distension and/or perforation between days 2 and 17 of life. Twelve patients required operative intervention. Findings invariably included one or more obstructing meconium plugs with proximal distension and frequent necrosis of the dilated segments. Surgical options consisted of resection or enterotomy, accompanied by primary closure or by distal irrigation and exteriorization. Irrigation led to iatrogenic bowel injury in two patients. One patient was managed successfully with oral and rectal gastrograffin and oral acetylcysteine. Ten patients were discharged, all of whom had normal stooling patterns and tested negatively for cystic fibrosis. Three patients died, two from the primary disease. The markedly premature infant is at risk for obstruction and eventual perforation secondary to meconium plugs, presumably formed in conjunction with intestinal dysmotility. Prompt diagnosis and timely intervention require a high index of suspicion, attention to stooling patterns and abdominal examinations, and screening radiographs when indicated.

Nutrition support teams: past, present, and future.

Nutrition support teams have evolved rapidly and grown in numbers since the early 1970s. While not all hospitals have or need nutrition support teams, the team approach has been demonstrated to be an excellent mechanism for identifying patients in need of nutrition support, reducing the complications associated with enteral and parental nutrition, and providing cost-effective nutrition support in a variety of hospital environments. The organization of a nutrition support team is reviewed, and suggestions are outlined for team survival in this uncertain era of health care reform. New JCAHO standards are reported which require performance-based interdisciplinary delivery of nutrition support, and make it more likely that efficiently organized nutrition support teams will thrive and continue to make important contributions to safe and cost-effective health care now and in the immediate future.

A clinician-driven home care delivery system.

The financial, entrepreneurial, administrative, and legal forces acting within the home care arena make it difficult for clinicians to develop and operate home care initiatives within an academic setting. HomeMed is a clinician-initiated and -directed home care delivery system wholly owned by the University of Michigan. The advantages of a clinician-directed system include: Assurance that clinical and patient-based factors are the primary determinants of strategic and procedural decisions; Responsiveness of the system to clinician needs; Maintenance of an important role for the referring physician in home care; Economical clinical research by facilitation of protocol therapy in ambulatory and home settings; Reduction of lengths of hospital stays through clinician initiatives; Incorporation of outcome analysis and other research programs into the mission of the system; Clinician commitment to success of the system; and Clinician input on revenue use. Potential disadvantages of a clinician-based system include: Entrepreneurial, financial, and legal naivete; Disconnection from institutional administrative and data management resources; and Inadequate clinician interest and commitment. The University of Michigan HomeMed experience demonstrates a model of clinician-initiated and -directed home care delivery that has been innovative, profitable, and clinically excellent, has engendered broad physician, nurse, pharmacist, and social worker enthusiasm, and has supported individual investigator clinical protocols as well as broad outcomes research initiatives. It is concluded that a clinician-initiated and -directed home care program is feasible and effective, and in some settings may be optimal.

Efficacy of the Nissen fundoplication in the management of gastroesophageal reflux following esophageal atresia repair.

From January 1974 to December 1988, 80 patients with esophageal atresia (EA) and tracheoesophageal fistula (TEF) were treated at the C.S. Mott Children's Hospital with division of their TEF and esophagoesophagostomy. Thirty-four in this group developed gastroesophageal reflux (GER). After an unsuccessful trial of medical management, 21 underwent Nissen fundoplication, and an additional child with refractory GER died intraoperatively before completion of her fundoplication. Following fundoplication, only eight patients had an uncomplicated course with elimination of reflux and no postoperative dysphagia. Wrap disruption and recurrent reflux occurred in 7 of the 21 (33%), a markedly higher incidence than the 10% figure seen in 220 children without EA who have undergone fundoplication at this institution. Upward tension on the wrap due to the presence of a shortened esophagus probably predisposes to an increased frequency of fundoplication failure in the EA child. In addition, postoperative dysphagia requiring prolonged gastrostomy feedings complicated eight otherwise successful initial or redo-fundoplications. Prolonged dysphagia in this group is likely related to the inability of the dyskinetic esophagus, common in EA, to overcome the increased resistance caused by the Nissen fundoplication. Three deaths (14%) from complications related to antireflux surgery occurred in the series. Although 15 of the 21 children (71%) eventually had excellent long-term results following initial or redo-fundoplication with elimination of reflux and normalization of oral intake, morbidity and mortality were clearly significant. Due to the high incidence of postoperative dysphagia and recurrent reflux, the transabdominal Nissen fundoplication may not be appropriate in EA patients.

Prenatal ultrasonography and early surgery for congenital cystic disease of the lung.

With the recent advent of prenatal ultrasound as a routine screening procedure, diagnosis of congenital cystic lung disease has been made in utero, raising the possibility of elective surgery for these lesions early in infancy before the patient develops respiratory distress or potentially life-threatening infection. From 1979 to 1989 six cases of congenital lung cyst were diagnosed in utero by prenatal ultrasound and followed during pregnancy. Two of the six were not confirmed after birth because the mothers preferred an abortion. The remaining four cases were studied periodically during gestation by ultrasonography. At birth, the first infant developed respiratory distress and underwent urgent left upper lobectomy and left lower segmentectomy at age 18 hours. The other three underwent elective lobectomy at age 10 days, 3 months, and 7 months, respectively. The fourth infant had a normal chest x-ray and ultrasound at birth, and the congenital cysts were confirmed by computed tomography scan. The pathological diagnosis in all four cases was cystic adenomatoid malformation. In two cases, intraoperative measurement of pulmonary function demonstrated significant improvement after resection of the affected lobe. We conclude that congenital lung cysts can be accurately diagnosed by prenatal ultrasound "screening" as early as 18 to 24 weeks' gestation. Advantages of early diagnosis include the option of moving the mother and unborn child to a high-risk obstetrical center for urgent operation on the newborn infant if necessary. Otherwise, once the diagnosis is confirmed, surgical correction can be performed electively and safely before respiratory distress or pulmonary infection complicates the infant's growth and development.

Permanent central venous access devices.

The development of permanent central venous access devices in the last 20 years has been accompanied by decreased complication rates, improved patient comfort, and increased cost-effectiveness. Subclavian venous access, first applied to infants and small children in the early 1970s, has given way to the Silastic permanent right atrial catheter by both cutdown and percutaneous techniques. The disadvantages of an occlusive aseptic dressing, frequent catheter irrigation, and disturbance of body image led to development of the totally implantable venous access system, which has been successfully used for long-term infusion of chemotherapeutic agents, antibiotics, blood products, and total parenteral nutrition. The recent introduction of permanent peripheral central venous catheters has further decreased the expense and complication rate of long-term venous access in infants and children. These developments and the accumulated expertise in finding alternative venous access sites (common facial, deep inferior epigastric, lumbar, and azygos veins) have helped minimize mechanical and septic complications and have increased the safety of even the most difficult venous access procedures.

Intravenous nutrition for the pediatric patient.

Nutritional management of infants and children differs from that of adults because of the extra requirements for growth and the limitations of physiological immaturity. Although parenteral nutrition (PN) is an accepted practice and a potentially life-saving therapy for pediatric patients who cannot be fed through their gastrointestinal tract, it is associated with the risk of serious metabolic, mechanical, and infectious complications. Candidates for PN should be selected according to well-defined indications, with initial nutritional assessment and with careful attention given to fluid, electrolyte, vitamin, trace element, and caloric requirements. Total calories should be administered so that the nonprotein-calorie to gram-nitrogen ratio is in the range of 150 to 250:1. Although short-term supplemental nutritional support can be administered through a peripheral vein, long-term total PN is best delivered by central venous access. PN should be initiated and monitored in accordance with well-established protocols. The lowest complication rate and highest cost-effectiveness are achieved by an interdisciplinary team that includes one or more nurses, dietitians, pharmacists, and physicians. The development of safe, reliable, and miniaturized intravenous pumps with built-in monitors has made home parenteral nutrition possible and desirable in selected patients.

Efficacy and safety of total parenteral nutrition in pediatric patients.

Pediatric patients differ from adult patients because of active musculoskeletal growth and development of visceral organs and because they have a proportionately smaller nutritional reserve, especially premature infants. Measures of outcome of effective nutritional support in pediatric patients who have experienced trauma or medical disease or who have undergone surgical procedures include weight gain, increased height and circumference of the head, increased hepatic synthesis of plasma proteins, immunocompetence, decreased morbidity, improved survival, and fast recovery. If a pediatric patient cannot eat or be tube-fed enterally after 3 days of recovery and support with fluids, parenteral nutrition is indicated. Examples in which this treatment has dramatically decreased morbidity include gastroschisis, short-bowel syndrome, necrotizing enterocolitis, and Hirschsprung's disease. Contraindications to its use include severe congenital (usually genetic) defects and terminal cancer, conditions in which life expectancy and quality of life are severely decreased. The team approach to parenteral and enteral nutrition in pediatric patients is preferred, and stable patients receiving long-term nutritional support, including infants, should be considered for home parenteral nutrition. When administered by protocol, parenteral nutrition is safe in pediatric patients. In properly selected pediatric patients, direct and indirect costs for such therapy may be significantly less than those in adults, and the cost-to-benefit ratio is appreciably higher when life expectancy, parental pleasure, and potential work productivity are considered. Ethical and social issues in initiating and discontinuing parenteral nutrition are best decided during thorough empathic discussions between physicians and parents.

Intestinal vaginoplasty for congenital absence of the vagina.

Congenital absence of the vagina is rare and occurs as a result of aplasia of the Müllerian ducts (46,XX) or complete androgen insensitivity syndrome (AIS--46,XY). Both syndromes are associated with normal female external genitalia and these patients are raised as females. These children are usually treated during adolescence with chronic dilatation of the shallow vaginal introitus (pressure tube technique) or by skin graft vaginoplasty (McIndoe procedure). Neither of these procedures is entirely satisfactory, as both may lead to neovaginal stenosis, inadequate length, poor lubrication, or all three. We have recently modified the operation first described by Baldwin in which a loop of sigmoid colon or small bowel is isolated, closed at one end, and brought down on its vascular pedicle as a neovagina and anastomosed to the hymenal ring. We have performed this operation on four adolescents (mean age, 15 years) and two infants (aged 4 days and 14 months) with excellent results (mean follow-up, 7.5 years for the adolescents and 1.8 years for the infants).(ABSTRACT TRUNCATED AT 250 WORDS)

Redo fundoplication in infants and children with recurrent gastroesophageal reflux.

The Nissen fundoplication is well established as the surgical treatment for medically refractory gastroesophageal reflux (GER) in childhood. Recurrent GER following fundoplication is a challenging problem with a reported incidence ranging from 0% to 12%. From January 1974 to January 1989, 286 children have been treated for GER with Nissen fundoplication and gastrostomy tube placement at the University of Michigan C.S. Mott Children's Hospital; 242 of these children have been followed for an average of 30 months, the remaining 44 have been lost to follow-up. Twenty-nine children (12%) have developed recurrent reflux following fundoplication. Medical management with thickened upright feelings, gastrostomy feedings, or gastrojejunostomy tube feedings has been successful for 11 children with control of reflux symptoms. Five additional children who were treated nonoperatively died of coexistant medical problems within 2 months following documentation or recurrent reflux. The remaining 13 children have required redo fundoplication for wrap disruption or herniation, and an additional six children, initially treated at other institutions, have also undergone redo fundoplications. One other child treated at this hospital required redo fundoplication for a postoperative partial gastric volvulus causing gastric outlet obstruction. Of the 20 children who have undergone a second Nissen fundoplication, 16 (80%) are doing well without recurrent GER. Four children have developed recurrent GER with wrap disruption; 1 is doing well following a third fundoplication, 2 have been managed successfully with continuous feedings via gastrojejunostomy feeding tubes, and a fourth child died of complications related to a recurrent tracheoesophageal fistula. Conservative management with gastrojejunal tube feedings should be considered in the initial management of children with recurrent GER following fundoplication.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term follow-up of brain-damaged children requiring feeding gastrostomy: should an antireflux procedure always be performed?

Due to the frequent presence of latent gastroesophageal reflux (GER) in mentally impaired children, it is now standard to perform upper gastrointestinal contrast (UGI) and pH probe studies in all children referred for feeding gastrostomy, even if they are without clinical evidence for GER. For patients with documented GER, an antireflux operation performed in conjunction with gastrostomy is usually considered mandatory. Some authors have suggested that a "protective" antireflux operation be performed at the time of gastrostomy placement in all brain-damaged children, citing a high incidence of postoperative GER in this group of patients following gastrostomy, even with a negative preoperative evaluation for GER. To evaluate this theory, we prospectively studied, over the past 6 years, all mentally retarded children referred for feeding gastrostomy with UGI contrast and esophageal pH probe studies. In total, 148 children were studied; 105 had a positive evaluation for GER and underwent gastrostomy and antireflux surgery. Of the 43 children with a negative preoperative evaluation for GER, 37 are doing well following gastrostomy alone without clinical reflux at an average follow-up of 21 months. Six of the 43 (14%) developed symptomatic GER occurring at an average of 10 months following gastrostomy placement. Five of these children have been successfully treated with an antireflux operation and the sixth patient has been successfully managed nonoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

A study of the lethal effects of intravenous injection of thrombin in rabbits.

Thrombin can stop bleeding during ophthalmic surgery by directly converting fibrinogen to fibrin. Little attention has been given to the potential risk of inadvertent intravenous administration of thrombin causing massive intravascular coagulation. We injected rabbits with a dose of thrombin, adjusted for body weight, equivalent to the amount used in ocular surgery. We also studied the effects of treating the rabbits with heparin. The rabbit injected with thrombin alone died within 30 seconds due to total intravascular coagulation. Three additional rabbits injected with thrombin but treated with heparin (intraperitoneally 40 minutes before thrombin, intravenously 30 minutes before thrombin, and intravenously immediately after thrombin injection) survived without any ill effects noted over the next month. For extraocular cases we recommend color coding the thrombin with some methylene blue. Using an eye dropper, rather than a syringe, reduces the chance of intravascular injection.

Hirschsprung's disease in adolescents and adults.

Hirschsprung's disease in the adolescent and adult is a rare and often misdiagnosed cause of lifelong refractory constipation. Two adolescent and three adult patients with Hirschsprung's disease treated between 1973 and 1987 at the University of Michigan Medical Center are reported. Each patient presented with chronic constipation requiring enemas, cathartics, and multiple hospital admissions for management. Diagnosis in each case was made with barium enema and full-thickness rectal biopsy. Four patients underwent endorectal pull-through procedures, all with good long-term results. The fifth patient, initially treated with a Duhamel retrorectal pull-through procedure, required reoperation for constipation secondary to a retained rectal septum. Review of 199 cases of adult Hirschsprung's disease enables comparison of the various operative procedures for this disorder with respect to postoperative complications and functional outcomes. Anorectal myectomy with low anterior resection, the Duhamel-Martin procedure, and the Soave endorectal pull-through procedure are the most acceptable methods for surgical management.

Sterility of total parenteral nutrient solutions stored at room temperature for seven days.

The sterility of total parenteral nutrient (TPN) solutions stored at room temperature for up to seven days after preparation was studied. The study was conducted in two parts. In part 1, a positive control phase was conducted to validate that the filter set would capture bacteria or fungi in the TPN solutions. In part 2,300 unused TPN solutions were retrieved from patient-care areas within 24 hours of preparation. These solutions were randomized into three study groups of 24, 72, or 168 hours after preparation. Each TPN solution was filtered aseptically using an inline 0.22-micron filter. The filters were suspended in brain-heart infusion broth and incubated at 35 degrees C. Filters were visually evaluated for turbidity as an indicator of microbial contamination. Microbial growth was reported in 2 of 100 samples filtered 24 hours after preparation (group 1) and in 1 of 100 samples filtered 72 hours after preparation (group 2). No growth was detected in TPN solutions filtered 168 hours after preparation (group 3). Turbid samples were subcultured, and contaminants were identified as coagulase-negative Staphylococcus species and gram-positive bacilli in the group 1 samples and coagulase-negative Staphylococcus species in the group 2 samples. The difference in contamination rates among the three groups was not significant. TPN solutions may be stored after preparation at room temperature for an extended time (up to 168 hours) without increasing the risk to patient safety. However, at this institution, expiration dates are extended only to the time that supports practical recycling of standard TPN solutions (72 hours).

Reversal of mortality for congenital diaphragmatic hernia with ECMO.

Extracorporeal Membrane Oxygenation (ECMO) has been available to neonates with respiratory failure at the University of Michigan School of Medicine since June 1981. In order to evaluate the impact of this type of pulmonary support, a retrospective analysis of 50 neonates with posterolateral congenital diaphragmatic hernia (CDH) who were symptomatic during the first hour of life and were treated between June 1974 and December 1987 was carried out. The patients were divided into two groups, those treated before June 1981 (16 patients) and those treated after June 1981 (34 patients). Overall survival improved from 50% (eight of 16 patients) during the pre-ECMO era to 76% (26 of 34 patients) during the post-ECMO period (p = 0.06). During the period after June 1981, 21 neonates were unresponsive to conventional therapy and were therefore considered for ECMO. Failure of conventional therapy was defined as acute clinical deterioration with an expected mortality of greater than 80% based on an objective formula previously reported. Six patients were excluded on the basis of specific contraindications to ECMO. Thirteen of 15 infants (87%) supported with ECMO survived. Three patients treated before 1981 met criteria for ECMO; all three died while receiving treatment using conventional therapy. These survival differences are significant (p less than 0.01). In addition, the survival of 87% for the infants treated with ECMO versus the expected mortality of greater than 80% for these same patients when treated with conventional therapy is highly significant (p less than 0.005). Based on this data, ECMO appears to be a successful, reliable, and safe method of respiratory support for selected, critically ill infants with CDH.

The development of necrotizing enterocolitis following repair of gastroschisis: a surprisingly high incidence.

We recently observed the development of necrotizing enterocolitis (NEC) in two consecutive newborn infants after gastroschisis repair. Because this association was unexpected, a retrospective review of our 11-year experience was performed using a multivariant computer analysis. The cohort consisted of 54 newborns with gastroschisis. All infants with omphalocele were excluded. Ten of 54 infants (18.5%) developed NEC as defined by classical clinical findings and pneumatosis intestinalis. Twenty-one distinct episodes of NEC occurred with up to three episodes (mean, 2.1) per patient. Twenty of the 21 episodes were successfully treated nonoperatively. Two infants developed pneumoperitoneum, one of whom underwent laparotomy upon which no perforation or intestinal infarction was found. Eight of the ten patients survived--a survival rate no different than for the remainder of the study group. Neither of the two deaths was attributable to NEC. The NEC was atypical in that no significant relationship was established with known predisposing conditions such as prematurity or low Apgar scores. Suspected risk factors such as time of feeding, type of closure, type of formula, total parenteral nutrition (TPN), and composition of TPN were not statistically related. Significant associations included concurrent TPN associated cholestatic liver disease in nine of the ten infants, antecedent intestinal surgery other than abdominal wall closure in five of the ten infants, and delay in initiation of enteral feedings (greater than 30 days) in eight of ten infants. In addition, the NEC occurred significantly later (range, 32 to 79 days; mean, 52 days) in the clinical course than usual; in fact, three of ten infants were rehospitalized with NEC following discharge. We conclude that a relationship exists between NEC and gastroschisis.(ABSTRACT TRUNCATED AT 250 WORDS)