Biomedical subjects
Publications and source records attributed to R W Powell.
An 8 year-old girl had a large congenital nevus involving the posterior thigh, leg, and foot. The nevus on non-weight-bearing areas was resected, and the areas were resurfaced with artificial skin and ultra-thin split-thickness grafts. A good result was ultimately achieved. Our management of this case and the relative merits of this new technology are detailed.
BACKGROUND/PURPOSE: Hypothermia (HT) remains a significant stress to the newborn and has been implicated in the pathogenesis of necrotizing enterocolitis (NEC). The authors assessed the effect of transient HT (32 degrees C) on regional organ blood flow in anesthetized piglets at age 7 to 10 days preterm (PREM), 1 to 2 days (NB), and 1 to 2 weeks (NEO). METHODS: Radiolabeled microspheres were used to determine organ blood flows (mL/min/g) at baseline, 15, and 60 minutes after HT and 60 minutes after rewarming to baseline core temperature. RESULTS: Heart rate and cardiac output decreased significantly in all groups. Cardiac flow decreased significantly in the NEO group, and central nervous system (CNS) flow decreased significantly in the NB and NEO groups. Both returned to baseline levels after rewarming. The PREM group experienced decreased cardiac, CNS, and intestinal blood flows but not to significant levels. NB and NEO intestinal blood flow showed significant decreases, which remained so after rewarming (a response not seen in hypoxia or hypovolemia). Cardiac output did not return to baseline levels in any group. CONCLUSIONS: HT causes derangements in organ blood flows that differ from other deleterious stimuli such as hypoxia and hypovolemia. The prolonged intestinal ischemia supports HT as a factor in the development of NEC. This delay may offer opportunity to intervene in an attempt to lessen ischemia-reperfusion injury.
Atlanto-occipital dislocation occurs more often in children due to the laxity of the ligamentous structures anchoring the occiput to the axial skeleton. The mechanism of action usually involves a sudden acceleration-deceleration force on the head of the child. The dislocation usually severs the spinal cord at the foramen magnum, resulting in acute respiratory arrest. We have managed four patients who sustained this injury and arrived at our trauma center with signs of life. Two patients were hemodynamically unstable, had positive diagnostic peritoneal lavage, and underwent splenectomy. Both patients had obvious separation of the occiput and C1 on lateral cervical spine films. Both remained very unstable and died soon after celiotomy. The other two patients were stabilized, and both met criteria for brain death; one family agreed to organ donation. A 5-year analysis revealed 57 pediatric deaths, with 10 patients sustaining atlanto-occipital dislocations (17.5%). Nine of 10 patients sustained other injuries, but in only 2 patients were the injuries immediately life-threatening. With continued improvement in emergency medical systems and pediatric trauma care, we can expect to see more pediatric patients with this injury arriving in trauma centers with signs of life. In our experience, 50 per cent of patients may meet organ donor criteria, and our incidence of this injury (17.5%) reveals atlanto-occipital dislocation as a major contributor to pediatric trauma mortality.
A girl born with laryngeal stenosis, tracheal esophageal fistula and esophageal atresia, imperforate anus, duodenal atresia, and Mayer-Rokitansky-Kuster-Hauser syndrome is presented. An explanation of the abnormalities and the surgical approach are presented.
Increased intra-abdominal pressure represents a difficult problem when closing abdominal wall defects (AWD) and can cause renal insufficiency and vascular injury to the intestine with the development of necrotizing enterocolitis. Urinary bladder pressure measurements have been shown to accurately reflect intra-abdominal pressure in animal models. This study compares outcomes with and without vesical pressure measurements in AWD. Since its description in 1987, these vesical pressure measurements have guided the closure of AWDs. A pressure of <20 cm H2O allows closure by primary fascial, skin, or staged prosthetic closure. All charts of patients who underwent AWD closure from 1981 to 1993 were reviewed and data collected including type of defect and closure, gestational age, weight, age at operation, fluid requirements and urinary outputs, ventilator requirements, days to first and total feeding, total parenteral nutrition (TPN) days, hospital days, hospital charges, morbidity, and mortality. Results were analyzed by paired or unpaired Student's t test or Fisher's exact test. Twenty-seven infants did not receive vesical pressure measurements, whereas 13 did. No significant differences occurred in the parameters recorded in these two diverse groups. When gastroschisis patients only were compared, a significant decrease in intravenous fluid requirements in the vesical measurement group occurred on postoperative Day 2 (155.3+/- 37.5 versus 109.6 +/- 34.3; P = 0.016), and a significant decrease in urinary output occurred on postoperative Day 3 (4.2 +/- 112 versus 3.1+/- 1.1; P=0.044). Ventilator support, TPN days, and oral feeding data were all lower in the vesical measurement group but did not reach statistical significance. Hospital days and hospital changes showed a trend to lower values in the measured group (P values 0.052 and 0.095, respectively). Intraoperative vesical pressure measurements represent a simple, safe, effective method to guide the closing of AWD and result in less capillary leak and more prompt diuresis, and may result in significantly less morbidity, mortality, and cost.
Acute hemorrhage in premature infants occurs as the result of obstetrical complications, birth trauma, or operative procedures. This study evaluates the response of the preterm piglet to acute hemorrhage and resuscitation. Piglets delivered by Caesarean section 7-14 days preterm underwent acute arterial/venous hemorrhage (20 cc/kg). At 0, 15, and 60 min after hemorrhage, hemodynamic parameters and regional blood flows (reference organ technique) were measured. Animals were then resuscitated with shed blood (20 cc/kg), crystalloid (60 cc/kg), or colloid (dextran 40, 20 cc/kg) with study parameters obtained 30 min later (statistical analysis by ANOVA). Significant decreases in blood pressure (BP) and cardiac output (CO) occurred after hemorrhage. BP and CO were reestablished to near control levels following resuscitation with blood and crystalloid. Dextran failed to return BP to baseline; however, it resulted in CO 1.7 x control. Heart and CNS blood flow were not significantly influenced by hemorrhage; however, dextran increased flows to these organs significantly above control levels. In the kidney and small bowel, flows decreased significantly following hemorrhage; blood and crystalloid restored flows to near baseline, while dextran resulted in flows significantly greater. In summary, the preterm piglet responds to hemorrhage with maintenance of blood flow to the heart and brain and significantly decreased flows to the kidney and small intestine. Flows following resuscitation with blood and crystalloid are comparable to those in control. Dextran resuscitation resulted in flows significantly greater than baseline; this response might be detrimental with ongoing hemorrhage and/or prolonged ischemia.
Stapled anastomoses of the gastrointestinal tract, commonplace in adults and older children, are rarely performed in newborns because of the size of the instruments. The development of smaller stapling devices for laparoscopic and thoracoscopic procedures presented an opportunity to evaluate the efficacy of such anastomoses in neonates and infants. Over an 11-month period, seven newborn or young infants underwent stapled functional end-to-end small or large intestinal anastomoses using the Endo-GIA 30. The male:female ratio was 3:4, and the mean age was 72d (range, 1 to 134 days). The mean weight at the time of the stapled anastomosis was 3.7 kg (range, 1.88 to 6.6 kg). The clinical setting requiring the intestinal anastomoses included ileostomy closure after perforated necrotizing enterocolitis (3), intestinal atresia (1), distal ileal volvulus (1), left colon mesenteric cyst (1), and biliary atresia (1). There were no deaths or anastomotic leaks. Nasogastric decompression was discontinued at a mean of 6 days (range, 3 to 11 days), and oral feedings were begun at a mean of 7.0 days (range, 4 to 12 days). The patients were discharged from the hospital 7 to 117 days after the operation (mean, 33 days). The endoscopic stapling instrument is safe and effective in performing small and large intestinal anastomoses in newborns and young infants.
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OBJECTIVE: The authors determined the effects of dopamine and dobutamine on organ blood flow in newborn piglets. SUMMARY BACKGROUND DATA: Although the hemodynamic effects of dopamine and dobutamine are well described in adults, little is known of their consequences in neonates, and their impact on organ perfusion in premature infants is unclear. METHODS: Cannulae were placed in the femoral vessels and left atrium of term (1-14 days old) and prematurely delivered (Ceasarean section at 90% of term gestation) piglets. After stabilization, radiolabeled microspheres were injected. A continuous infusion of dopamine or dobutamine was started, and other microspheres were injected at 5, 10, and 15-micrograms/kg/minute drug doses (allowing a 20-minute equilibration period at and between each dose). Blood flows (mL/minute/g tissue) to organs were determined using reference organ techniques. RESULTS: In term animals only, dobutamine and dopamine increased systemic mean arterial pressure at the 15-micrograms dose. In term piglets, dobutamine produced dose-dependent increases (p < 0.05, analysis of variance) in heart and brain blood flow, although small intestinal blood flow decreased (1.47 +/- 0.13 mL/minute/g baseline to 1.31 +/- 0.11 mL/minute/g at 15-micrograms dose). There were no significant changes in blood flow to these organs in preterm animals. Dopamine significantly (p < 0.05) increased heart blood flow in both groups. Dopamine also increased small intestinal blood flow in term (1.63 +/- 0.22 mL/minute/g baseline to 3.13 +/- 0.34 mL/minute/g at 15-micrograms dose) and premature (0.31 +/- 0.10 mL/minute/g baseline to 1.11 +/- 0.29 at 15 micrograms dose) piglets. CONCLUSIONS: Dopamine may prove a valuable adjunct when a premature infant is at risk for conditions that reduce alimentary tract blood flow.
Age, degree of injury, different metabolic rates, and growth complicate the estimation of nutritional requirements in the pediatric trauma victim. This study was designed to determine energy requirements of the injured child in relation to injury severity. Fourteen patients of 600 seen in a 5-year period met our criteria for evaluation with significant weight loss, caloric deficit recorded to the lowest weight, and details of injury. There were 10 males and four females with a mean age of 11.24 years (+/- 5.5). Mean injury scores included ISS 24.24 +/- 5.96, PTS 4.8 +/- 1.7, and TSS 11.79 +/- 2.78. The closest Theoretical Caloric Requirement (ThCR) that would have produced the Cumulative Caloric Deficit was calculated from the actual weight loss and Caloric Intake. Eighty-six per cent of the ThCR were less than or equal to the 1989 Recommended Dietary Allowances (RDA) (mean -16.43 +/- 24%). The per cent increase of the ThCR above the basal was significantly higher for lower ISS scores (P < 0.05). When compared to RDA, the per cent change of the ThCR for mild injuries were 1.8 +/- 27.9% above the RDA and were 26.5 +/- 17.2% below the RDA for the severe injuries. These findings are consistent with the child with milder injuries resuming activity and the growth process earlier than a severely injured child. We would recommend calculating caloric requirements based on the RDA for milder injuries and on 0.75 RDA for the more severely injured child (ISS > 25).
Newborn piglets (aged 1 to 2 days and 7 to 14 days) were used to study (1) the redistribution of organ blood flow after a 25% acute blood loss and (2) the response to resuscitation with shed blood (20 mL/kg), crystalloid (normal saline [NS] or lactated Ringer's [LR]; 60 mL/kg), and colloid (Dextran-40, 20 mL/kg). Hemodynamic parameters showed little differences in the response to hemorrhage and resuscitation. The two age groups had no significant differences in parameters or blood flow (results combined). The animals maintained flow to the heart and central nervous system (CNS) and had significantly decreased flow to the kidneys and splanchnic organs. In the gastrointestinal tract, the small intestine was affected most severely, with a significant decrease in blood flow, especially to the mucosa. In all organ systems, Dextran 40 restored blood flow to levels significantly above the baseline. Shed blood and crystalloid restored flow to organs sustaining decreased flow, but crystalloid did not restore flow to the baseline level in the kidney and all segments of the gastrointestinal tract.
Between January 1983 and December 1991, 80 women with AJCC clinical stage I or II breast cancer were treated with conservative surgery and radiation therapy. Reexcision of the primary was performed in 40 breasts, and residual tumor was identified in 40% of these. Margins of resection were assessed in 80% and, of these, 46 patients had final margins of resection that were negative, 86% had axillary node dissection, 45 patients had histologically negative axillary nodes, and 24 had histologically positive axillary nodes. Of patients with histologically positive lymph nodes, 92% received systemic adjuvant treatment consisting of chemotherapy in 19/24 and tamoxifen in 14/24. Median follow-up was 34 months (range: 6-90 months). The adjusted 5-year actuarial Overall Survival for the group was 92%, and Disease-Free Survival was 80%. The 5-year Local Recurrence-Free Survival was 96%. The present study confirms the excellent results that can be obtained with conservative surgery plus radiation therapy.
Peripheral vascular reconstructions are common operations for the treatment of occlusive atherosclerosis, and the vast majority are uncomplicated. However, despite all precautionary measures, a small percentage of patients will manifest wound infection and graft exposure that may evolve to loss of limb and/or life. Treatment has traditionally consisted of systemic administration of antibiotic medication(s), graft extirpation, and extra-anatomic arterial bypass; yet despite use of these more radical modalities, morbidity and mortality have remained high. An additional meritorious adjunct for the treatment of exposed prosthetic or autogenous saphenous vein arterial bypass grafts is the use of local/regional autogenous skeletal muscular rotational flaps. Reported herein are the results of this technique applied to the inguinofemoral regions of eight patients. Rectus abdominis (1 patient), rectus femoris (4), and sartorius (4) skeletal muscular rotational flaps were employed. Seven of eight (88%) patients convalesced well at mean duration of follow-up measuring 24 months, although one patient subsequently required major amputation due to progression of occlusive atherosclerosis. One of eight (12%) patients succumbed secondary to irreversible sepsis, despite radical amputation. The data suggest that use of local/regional skeletal muscular rotational flaps is a useful adjunct for the treatment of patients with exposed arterial conduits.
Intradural extension of a sacrococcygeal teratoma (SCT) is extremely rare and only well-documented in presacral tumors that have been associated with a familial history, anorectal stenosis, and sacral dysraphism. This case documents the extension of a type I SCT into the dural sac with attachment to the filum terminale. A full-term female was transferred to our tertiary newborn intensive care unit with a sacral mass measuring 12 x 13 cm. It protruded from the buttocks and displaced the anus anteriorly. Rectal examination showed no presacral component. Radiographs demonstrated calcification in the soft tissue mass and a normal-appearing sacrum with the last sacral segment not visualized. At operation during dissection of the cephalad component, the SCT extended into the spinal canal. Neurosurgical consultation resulted in a sacral laminectomy which revealed the tumor to be attached to the tip of the filum terminale. The tumor was removed in toto with all sacral roots preserved. The infant required a second operation to revise a wound dehiscence and suspected cerebrospinal fluid leak. The final pathology report was benign SCT. Follow-up at 2 years showed no recurrence, normal sphincter tone, and a normal computed tomography scan. This represents the first well-documented intradural extension of a Type I SCT with attachment to the spinal cord. This extremely rare occurrence requires awareness with the availability of neurosurgical support to expedite operative management.
Indomethacin (IND), widely used in premature infants to effect nonoperative closure of patent ductus arteriosus (PDA), has been implicated in gastrointestinal tract (GI) perforations and necrotizing enterocolitis (NEC). The vasoactive effects of IND could simultaneously affect regional blood flow distribution, specifically a decrease in intestinal blood flow. This study determined blood pressure (BP), heart rate (HR), cardiac output (CO), total peripheral resistance (TPR) and regional blood flows (mL/min/g) at baseline, 15, 60, and 120 minutes after intravenous infusion of IND (0.4 mg/kg) in three groups: preterm piglets delivered 7 to 10 days before term; 1- to 2-day-old piglets; and 7- to 14-day-old piglets. IND did not significantly affect hemodynamic parameters (BP, HR, CO, TPR) or regional blood flows to the heart, central nervous system, kidney or GI tract in the premature animals. In 1- to 2-day-old animals, a significant increase in BP and TPR occurred at 120 minutes, with significant decreases in blood flow to the GI tract in the esophagus, stomach, and rectosigmoid. In the 7- to 14-day group CO significantly decreased while TPR increased. Significant decreases in blood flow occurred throughout the GI tract, most pronounced in the small intestine and colon, essentially due to decreased mucosal blood flow. Our study indicates that indomethacin can cause selective GI tract mucosal ischemia, and that the effect is increased in the more developed animal. This effect on mucosal blood flow suggests the GI tract disturbances seen after IND administration are due to an ischemic injury to mucosa previously affected by ischemia-reperfusion injury from other stresses.
Eighteen very low-birthweight infants with necrotizing enterocolitis (NEC) underwent periodic neurodevelopmental testing until two years of age. They were grouped according to whether they had had surgical intervention (N = 6) or non-surgical therapy (N = 12). At eight and 15 months corrected age, a significantly greater number of the surgical group exhibited motor delay. At 24 months, only one infant in the surgical group had persistent motor delays. These findings indicate a higher incidence of motor delays in infants requiring surgery for NEC. The delays involved skills influenced by the abdominal musculature. These motor delays persisted up to 24 months, but appeared to resolve with time.
Acute splenic sequestration crisis (ASSC) in children with various forms of sickle cell disease can result in life-threatening circulatory collapse due to the loss of circulating blood volume. Over a 6-year period we have treated 12 patients ranging in age from 5 1/2 months to 7 years presenting with acute sequestration crisis. Eleven had homozygous sickle cell disease and the other had sickle-thalassemia. One patient died of acute circulatory collapse. Eight patients underwent splenectomy after a major episode of sequestration with no serious infectious complications up to 5 years following splenectomy. Three patients with minor episodes have been followed with no recurrences. To foster early detection of this potentially lethal complication of sickle cell disease, an educational program in our Comprehensive Sickle Cell Center instructs the parents to examine the spleen and bring their child in for evaluation if the spleen enlarges. A newly developed videotape describes the common symptoms of ASSC and illustrates the technique of palpating the spleen. With early detection of sickle cell disease by neonatal screening and the educational program, the morbidity and mortality from this complication of sickle cell disease can be reduced.
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