Biomedical subjects
Publications and source records attributed to Denis D Bensard.
We review a case of a diaphragmatic hernia simulating on chest radiograph left lower lobe pneumonia and associated pleural effusion. We also characterize the atypical chest radiographic findings of this patient and recommend further imaging with computed tomography in unusual patient presentations.
BACKGROUND: Toll-like receptors (TLRs) serve as mediators of innate immune responses to pathogen-associated molecular patterns (PAMPs) which include lipopolysaccharide (LPS) and staphylococcal enterotoxin B (SEB). TLR-4 is thought to act as the primary effector of LPS recognition and TLR-2 is thought to mediate responses to Gram-positive bacterial proteins. Chemokines such as macrophage inflammatory protein (MIP-2) are peptides that are responsible for lung neutrophil (PMN) sequestration following an infectious or inflammatory insult. Given the Gram-positive origin of SEB, we hypothesized that mice with altered TLR-4 signaling would exhibit no difference in lung PMN sequestration following SEB when compared to wild-type mice. METHODS: Wild-type and TLR-4 mutant mice were administered intratracheal saline, LPS (Escherichia coli 0.1 mg/kg), or SEB (1 mg/kg). After 24 h, lung PMN accumulation was determined by myeloperoxidase (MPO) assay and bronchoalveolar lavage fluid cell count (BALfcc). Total lung and BALf MIP-2 was measured by enzyme-linked immunosorbent assay. RESULTS: There was an increase in lung PMN accumulation (by both MPO and BALfcc) and MIP-2 following LPS and SEB in wild-type mice compared to saline-treated controls. In contrast, TLR-4 mice failed to exhibit an increase in lung MIP-2 or PMN accumulation following either LPS or SEB compared to wild-type mice. CONCLUSIONS: TLR-4 mutant mice are unresponsive to intratracheal LPS. SEB elicited an increase in lung MIP-2 and PMN accumulation in wild-type mice. However, TLR-4 mutant mice were protected from this process. This suggests that TLR-4 signaling may mediate the responses to other PAMPs in addition to LPS.
BACKGROUND: Traditional surgical teaching stresses that hypotension is an indicator of loss of circulating blood volume. The purpose of this study is to critically evaluate hypotensive injured children for evidence of a hemorrhagic insult. METHODS: Over a 2-year period, data were collected prospectively from children injured via a blunt mechanism. Systolic blood pressure (SBP) was recorded in the field and on arrival to the emergency department. RESULTS: In all, 194 injured children were identified as hypotensive. Only 82 (42%) had identifiable injuries to account for significant volume loss. Children 0 to 5 years old had a 61% incidence of isolated head injury (46 of 76) and only a 34% incidence of hemorrhagic insult (26 of 76). Children 6 to 12 years old had a 31% incidence of isolated head injury (22 of 72) and a 52% incidence of hemorrhagic insult (38 of 72). Finally, patients more than 12 years old had a 33% incidence of isolated head injury (15 of 46) and a 39% incidence of hemorrhagic insult (18 of 46). CONCLUSIONS: Hypotension should not be viewed only as a potential marker of loss of circulating volume, but also as a possible indicator of head injury in young trauma victims.
PURPOSE: Injury is the leading cause of cardiac arrest in children older than 1 year. Previous findings suggest that children who require cardiopulmonary resuscitation (CPR) administered by paramedics for any reason rarely survive to hospital discharge. The authors evaluated the outcome of children sustaining cardiac arrest after blunt trauma in a Regional Pediatric Trauma Center. METHODS: Children (age < 16) who underwent CPR in the field or in the emergency department (ED) after blunt trauma were identified from the trauma registry of a regional pediatric trauma center over a 3-year period (1997 to 2000). Patient demographics, rate of survival to discharge, factors influencing survival, and organ donation data were obtained from the trauma registry and medical record. Probability of survival (Ps) was calculated by TRISS analysis. RESULTS: Twenty-five children were identified with a history of cardiac arrest after blunt injury (mean age; 3.3 years; range, 0.1 to 10; mean ISS, 30.7; range, 13-75; mean RTS, 1.58). Mean calculated Ps was 22.7%. However, only 2 (8%) survived. Death in the majority (91%) of the 23 patients who died occurred secondary to brain or spinal cord injury, and only 2 (9%) occurred as the result of exsanguinating hemorrhage. CPR was first performed in the field in 10 patients (40%), en route in 6 (24%), and in the ED in 9 (36%). Of the children who survived, both had vitals in the field, and CPR was administered initially in the ED. Mean length of ED resuscitation before death was 80 minutes. Of the children who died, organ donation occurred in only 3 (13%). The 2 survivors had no head injury and were discharged within 3 weeks of injury. CONCLUSIONS: Cardiopulmonary resuscitation after blunt injury in children rarely results in survival. The majority of deaths occur as a result of isolated intracranial injury and not exsanguinating hemorrhage. Although all children should receive aggressive resuscitation after injury, the need for CPR in the field portends a poor outcome. Furthermore, these data would suggest that prolonged or heroic efforts for children sustaining cardiac arrest in the field are not indicated.
BACKGROUND/PURPOSE: Although thoracoscopy in children is a well-accepted technique, there are limitations to this approach. Small lung nodules or those not located on the pleural surface often require an open thoracotomy. The purpose of this report is to evaluate the utility of computed tomography (CT) guided needle localization of lung nodules in children followed by thoracoscopic resection. METHODS: From 1997 to 2000, 13 thoracoscopic procedures were performed on 12 children who presented with small pulmonary nodules (<1 cm) or nodules deep to the pleural surface. Preoperative needle localization was performed by injecting methylene blue under CT guidance. Patients then were taken directly to the operating room for thoracoscopic resection. RESULTS: All 13 procedures were completed successfully thoracoscopically. Twelve yielded diagnostic pathologic findings as well as therapeutic resections in 7. All patients underwent extubation in the operating room, and chest tubes were removed within 36 hours. No thoracotomies were performed, and there were no complications. CONCLUSIONS: Preoperative localization utilizing CT guidance is safe and beneficial in children with pulmonary nodules less than 1 cm in size and those located deep to the pleural surface. This technique allows the surgeon to perform thoracoscopy for diagnosis and therapeutic resection of these lesions rather than submitting patients to the morbidity of a thoracotomy.
BACKGROUND/PURPOSE: Neutrophils (PMNs) are well known effectors of lung injury after sepsis. The accumulation of PMNs into the lung is dependent on a complex cascade of events that includes the local production of chemokines. Interestingly, neonates are protected from lung injury after zymosan-induced sepsis. The authors hypothesized that this protection was caused by either altered PMN function or diminished lung chemokine production compared with the adult. METHODS: Sepsis was induced in neonatal and adult rats by an intraperitoneal injection of zymosan. Animals were killed 24 hours later and lungs examined for PMN accumulation and function, chemokine production, and lung injury. RESULTS: Septic neonates (SN) were protected from pulmonary edema when compared with septic adults (SA). Lung PMN number and chemokine (MIP-2) production increased in both septic neonates and adults when compared with vehicle (V) treated animals. Conversely, PMN function was decreased significantly in neonates when compared with adults. CONCLUSIONS: Despite equivalent lung PMN accumulation and chemotactic protein production, PMN function and lung injury in septic neonates was diminished when compared with that of adults. These findings suggest that neonates may be relatively protected from sepsis-induced lung injury caused by immature PMN function.
BACKGROUND: Although postinjury multiple organ failure (MOF) is a well-described phenomenon in adults, the incidence of this syndrome in children is unknown. The purpose of this study was to describe the incidence, course, and severity of pediatric postinjury MOF. We hypothesized that the incidence and severity of postinjury MOF in children would be less when compared with adults. METHODS: Patients were retrospectively identified from the trauma registry of a regional pediatric trauma center and an adult Level I trauma center with pediatric commitment for a 3-year period. All trauma patients less than 16 years old who survived for longer than 24 hours and had an Injury Severity Score > 15 were eligible. An accepted MOF score was used. Categorical variables were compared by chi2 and continuous variables by t test. A value of p< 0.05 was considered statistically significant. RESULTS: Of 534 patients identified, 334 (63%) were admitted for evaluation of isolated head injury and excluded from further analysis. The rate of postinjury MOF in children was found to be only 3%, with a low (17%) mortality when compared with historical adult data (50%). CONCLUSION: The incidence of postinjury MOF in the child is less than in the adult, given equivalent injury severity. These observations solidify the contention that postinjury MOF is rare in children, and is less severe when it occurs. Delineating the mechanism(s) whereby children are protected from postinjury MOF may provide insight into the development of strategies to prevent MOF in other age groups as well as various disease states.
The influx of neutrophils into tissues in response to inflammatory stimuli involves C-X-C chemokines. Interleukin-1 (IL-1) stimulates chemokine production in vitro, but its role in vivo on chemokine production is not as clearly understood. We hypothesized that IL-1 mediates in vivo tissue C-X-C chemokine production induced by systemic lipopolysaccharide (LPS). IL-1 activity was blocked by IL-1 receptor antagonist (IL-1Ra). Rats were injected with Salmonella typhi LPS (0.5 mg/kg) with and without prior administration of IL-1Ra. Cytokine-induced neutrophil chemoattractant-1 (CINC-1) and macrophage inflammatory protein-2 (MIP-2) protein and mRNA levels, tissue neutrophil accumulation, and indices of organ injury were measured. LPS administration resulted in increased plasma, lung, and liver IL-1beta that was decreased by Il-1Ra. LPS also induced an increase in plasma, lung, and liver CINC-1 and MIP-2 protein and mRNA. However, IL-1Ra had no effect on LPS-induced plasma or lung tissue CINC-1 levels. In contrast, IL-1Ra pretreatment did significantly decrease CINC-1 protein expression in the liver (45% decrease) and MIP-2 protein expression in plasma (100% decrease), lung (72% decrease) and liver (100% decrease) compared to LPS- treated controls. Steady-state mRNA levels by Northern blot analysis of both CINC-1 and MIP-2 in lung and liver were similar to the protein findings. Pretreatment with IL-1Ra also resulted in a 47% and 59% decrease in lung and liver neutrophil accumulation, respectively, following LPS. In addition, indices of both lung and liver injury were decreased in animals pretreated with IL-1Ra. In summary, LPS induces IL-1beta and MIP-2 expression in the lung and liver, both of which are IL-1 dependent. Although lung neutrophil accumulation in both lung and liver after LPS is also IL-1 mediated, lung CINC-1 levels were unaffected by IL-1Ra. These data suggest that IL-1 regulates tissue chemokine expression and neutrophil accumulation after LPS.
OBJECTIVE: Pediatric gastric access for long-term enteral feeding may be performed via a laparotomy, laparoscopy, or a percutaneous approach. In children and adolescents, laparoscopic-assisted gastrostomy may be difficult due to a thick abdominal wall. Therefore, if the abdominal wall is estimated to be >2 cm on physical examination, or in children in whom a percutaneous endoscopic gastrostomy was unsuccessfully attempted by a gastroenterologist, we routinely perform a laparoscopic-assisted percutaneous endoscopic gastrostomy. METHODS: From January 1998 through February 2003, we retrospectively reviewed 15 cases of a laparoscopic-assisted percutaneous endoscopic gastrostomy. Instruments used to perform this technique are a percutaneous endoscopic gastrostomy kit, an Olympus flexible endoscope, and one 5-mm STEP port placed through an infraumbilical incision for a 5-mm, 30-degree scope. RESULTS: Age range was 2 years to 20 years (mean, 10). Operative time ranged from 20 minutes to 45 minutes. When a concurrent laparoscopic Nissen fundoplication was performed (n = 6), the percutaneous endoscopic gastrostomy was placed after completion of the Nissen fundoplication. No intraoperative complications occurred, and all tubes were successfully placed. Feeds were instituted the following day and advanced to goal. To date, no postoperative complications have occurred, and revision has not been necessary. CONCLUSIONS: Laparoscopic-assisted percutaneous endoscopic gastrostomy in children and adolescents is safe and effective. Utilizing laparoscopy permits evaluation of the peritoneum and lysis of adhesions, if necessary. Moreover, laparoscopy provides excellent exposure for accurate placement of the PEG, while avoiding injury to other organs.
OBJECTIVE: Hypertrophic pyloric stenosis is a common pediatric surgical condition. A Ramstedt pyloromyotomy is performed either via laparotomy or laparoscopy. We report our first 25 cases of laparoscopic pyloromyotomy at an academic children's hospital. METHODS: From January 2002 through February 2003, we retrospectively reviewed our first 25 laparoscopic pyloromyotomies. All patients had documented hypertrophic pyloric stenosis by ultrasound criteria. Three incisions were made, one 5-mm umbilical port, one 3-mm right upper quadrant port, and a third left upper quadrant working stab incision. A 4-mm, 30 degrees scope was used in all cases. A longitudinal pyloromyotomy was performed using an arthrotomy scalpel. The pylorus was further separated with a laparoscopic Benson spreader. At the completion of the pyloromyotomy, the stomach was insufflated with air to identify any mucosal injury. RESULTS: Age range was 2.3 weeks to 8.4 weeks. Operating time has decreased from 70 minutes to 15 minutes. Two conversions to an open procedure were necessary, both during the first 10 cases. No mucosal perforations or incomplete pyloromyotomies have occurred. Feeds were started within 4 hours and advanced to goal. Time to discharge ranged from 12 hours to 30 hours. One patient developed umbilical cellulitis that was successfully treated with antibiotics. CONCLUSIONS: Laparoscopic pyloromyotomy is a safe, effective procedure for hypertrophic pyloric stenosis in a resident teaching environment. Laparoscopy permits excellent visualization, has comparable postoperative recovery, and superior cosmesis.
BACKGROUND: Ventriculoperitoneal shunt is the preferred treatment for hydrocephalus. Known complications include infection, obstruction, and disconnection with the fractured fragment migrating in the peritoneal cavity. We report 17 cases of laparoscopic evaluation and revision of ventriculoperitoneal shunts in children. METHODS: From January 2000 through October 2002, we retrospectively reviewed our experience with laparoscopy and ventriculoperitoneal shunts. RESULTS: Laparoscopy was performed in 17 children with a malfunctioning shunt, presumed shunt dislodgment or disconnection, reinsertion of a shunt after externalization, and primary shunt placement. Six patients (35%) were converted to an open laparotomy due to dense adhesions. Eleven patients (65%) underwent successful laparoscopic-assisted ventriculoperitoneal shunt placement: 5/11 (45%) had lysis of adhesions or pseudocyst marsupialization with repositioning of a functional shunt, or both; 3/11 (27%) had successful retrieval of a disconnected catheter with reinsertion of a new catheter; 2/11 (18%) had laparoscopic confirmation of satisfactory placement and function, requiring no revision; 1/11 (9%) had an initial shunt placed with laparoscopic guidance due to the obesity. Operative time for the laparoscopic procedure ranged from 30 minutes to 60 minutes. All laparoscopic procedures used 1-mm or two 5-mm ports. Perioperatively, no adverse neurological sequelae occurred due to the pneumoperitoneum. CONCLUSIONS: Laparoscopic guidance or revision of ventriculoperitoneal shunts permits (1) direct visualization of catheter insertion within the peritoneal cavity, (2) satisfactory positioning, (3) lysis of adhesions or marsupialization with catheter repositioning, or both, and (4) retrieval of fractured catheters.
OBJECTIVE: Laparoscopic Nissen fundoplication is performed in neonates and children for significant gastroesophageal reflux. An aberrant left hepatic artery encountered during laparoscopic Nissen fundoplication makes dissection around the esophageal hiatus more difficult if the artery is not transected. Although some suggest division of the aberrant left hepatic artery, this is associated with risk of significant hepatic injury from ischemia. We routinely preserve the aberrant left hepatic artery and sought to determine (1) the incidence of aberrant left hepatic artery and (2) the results following preservation of the aberrant left hepatic artery. METHODS: Between January 2000 and October 2002, 195 laparoscopic Nissen fundoplications were performed. We documented intraoperative findings of each procedure, and reviewed postoperative radiographic studies and clinic visits. RESULTS: In 30 patients (15%), an aberrant left hepatic artery was identified. All dissections were performed laparoscopically with the Nissen fundoplication positioned cephalad to the aberrant left hepatic artery. Postoperatively, 2 patients (6%) have had evidence of wrap failure. The remainder of the patients has had normal radiographic studies or no clinical evidence of reflux during clinic visits. CONCLUSION: During laparoscopic Nissen fundoplication in neonates and children, an aberrant left hepatic artery may be encountered in approximately 15% of patients. When an aberrant left hepatic artery is identified, it should be preserved to avoid the potential risk of hepatic ischemic injury.