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Biomedical subjects

M R Langham

Publications and source records attributed to M R Langham.

At least 37 records · Page 2Linked to original sources
PubMed1995

Physiologic response to two endotracheal suctioning techniques in newborn lambs with and without acute pulmonary hypertension.

BACKGROUND: Endotracheal suctioning may cause sudden increases in pulmonary arterial pressure, which can result in hypoxia secondary to right ventricular failure and/or increased right-to-left shunting. An adaptor that allows suctioning without disconnecting the ventilator has been proposed to prevent these problems; however, its efficacy has not been rigorously studied. OBJECTIVE: To examine the physiologic responses to two endotracheal suctioning techniques in newborn lambs with and without acute pulmonary hypertension. METHODS: A repeated-measures design was used to compare two endotracheal suctioning techniques in seven newborn lambs with and without acute pulmonary hypertension. An adaptor was used in the ventilator-controlled technique, making disconnection of the ventilator during suctioning unnecessary. In the bag-controlled technique, the ventilator was disconnected and ventilation was done with a manual resuscitation bag. Physiologic variables, pulmonary and mean arterial pressure, peak inspiratory pressure, mixed venous oxygen saturation, cardiac index, and arterial blood gas values were recorded before, during, and after endotracheal suctioning. RESULTS: Endotracheal suctioning caused a statistically significant systemic hypertensive response in lambs with and without acute pulmonary hypertension, regardless of which suctioning technique was used. No statistically significant changes occurred in pulmonary arterial pressure using either technique. CONCLUSIONS: Use of an adaptor resulted in no differences in the physiologic responses to endotracheal suctioning. However, endotracheal suctioning was easier to perform using an adaptor because no extra equipment or person was needed.

Animals↗
PubMed1993

Relationship of the polymerase chain reaction for cytomegalovirus to the development of hepatitis in liver transplant recipients.

In a pilot study, the polymerase chain reaction was found to be more sensitive than standard viral culture methods for the detection of cytomegalovirus, particularly from blood and tissues. We therefore applied this technique to 71 serially collected liver biopsies from 16 orthotopic liver transplant patients. All patients were CMV-seropositive (n = 15) or seroconverted (n = 1). Seven patients (9 biopsies) had histologically proved CMV hepatitis, and all these biopsies were CMV PCR-positive. Six of these 7 patients had a prior liver biopsy that was CMV PCR-positive, but culture and histology-negative, an average of 13.2 +/- 6.9 days before the histologically positive biopsy. The 7th patient was not biopsied prior to the diagnostic biopsy. Three patients had 7 liver biopsies that were CMV PCR-positive, but histologically negative for CMV hepatitis. Two of these three had CMV infection confirmed by viral culture of blood or liver biopsy. The remaining 6 patients had a total of 26 liver biopsies that were negative for CMV by PCR, culture, and histology. Among liver transplant patients, CMV PCR performed on liver biopsy specimens correctly identified all histologically proven cases of CMV hepatitis. CMV PCR positivity in liver tissue did not correlate with latent infection and preceded the development of CMV hepatitis or other meaningful CMV infection in 8 of 10 patients.

Biopsy↗
PubMed1993

Psychological adjustment of liver transplant candidates.

The psychological functioning of 20 adult liver transplant candidates was evaluated. Using standardized assessment instruments, we found few personality disturbances and normal levels of anger. However, clinically significant levels of depression and anxiety were reported for 28% and 37% of the sample, respectively. Moreover, patients whose coping strategies were characterized by avoiding the exigencies of their illness reported more depression, more anxiety, and increased psychopathology. Disease severity was also positively correlated with anxiety and avoidant coping strategies. Implications of these findings for the pre-transplant psychological evaluation are discussed.

Adaptation, Psychological↗
PubMed1992

Pseudomembranous colitis following resection for Hirschsprung's disease.

Enterocolitis is the most common cause of significant morbidity and death in Hirschsprung's disease. Although most cases respond to nasogastric decompression, antibiotics, and colonic evacuation, some children have an unusually fulminant or protracted clinical course. Four cases are reported of pseudomembranous colitis (PMC) that developed 1 to 18 months (mean, 8 months) after definitive surgery for Hirschsprung's disease (Soave endorectal pull-though, 2; Duhamel procedure, 2). While all children presented with fever, abdominal distention, and diarrhea, indistinguishable from typical Hirschsprung's enterocolitis, the clinical course was fulminant in two cases, both of whom died of septic shock. Postmortem examination in both showed extensive colonic pseudomembranes despite identification of Clostridium difficile toxin and subsequent vancomycin therapy (initiated late in the clinical course). Two children in the series had protracted hospitalizations and eventually required diverting enterostomy despite recognition of C difficile toxin and treatment with enteral vancomycin, in one child necessitating multiple courses of antibiotic therapy. Awareness of the virulence of PMC associated with Hirschsprung's disease (even after definitive resection) should prompt submission of stool specimens from any child who presents with enterocolitis for both C difficile culture and toxin levels. On the basis of our experience it is our policy to initiate a prompt course of vancomycin by rectal lavage or nasogastric tube in all children with Hirschsprung's enterocolitis, pending culture results, in view of the significant morbidity and mortality exemplified by cases in this review.

Administration, Rectal↗
PubMed1988

Use of the Greenfield filter in adolescents for deep vein thrombosis and pulmonary embolism.

Serious venous thromboembolic disease is now recognized more frequently in the pediatric age group. Caval interruption is indicated most commonly for prophylaxis against life-threatening or recurrent pulmonary embolism (PE) when anticoagulation is ineffective or contraindicated. Greenfield vena caval filters have been utilized locally in 415 adult patients with 97% long-term patency and 5% recurrent embolization. Its application in adolescents is reported herein. Standard adult (30-mm) vena caval filters were placed in ten patients, ages 13 to 18. Four filters were required following PE, six were used for deep venous thrombosis (DVT) when anticoagulation was contraindicated, and one was inserted prophylactically. In eight patients, filter insertion was accomplished with local anesthesia, while two underwent filter placement under general anesthesia administered for other procedures. One filter was misplaced into the right renal vein, requiring a second filter insertion. All patients have been followed from 1 to 11 years with yearly vascular duplex imaging and radionuclide venograms documenting caval patency without clinical embolic sequelae. This duplicates the adult experience in safety and efficacy. As recognition of venous thromboembolism becomes more frequent in the pediatric age group, safe caval interruption may be necessary for those excluded from or not responsive to anticoagulation. This technique may be extended to smaller patients with miniaturization of both filter and carrier.

Adolescent↗
PubMed1987

Extracorporeal membrane oxygenation following repair of congenital diaphragmatic hernias.

From 1981 through 1986, 8 newborns with congenital diaphragmatic hernia required herniorrhaphy in the first 8 hours of life. Extracorporeal membrane oxygenation (ECMO) was employed in 7 after they met local criteria predictive of 95% mortality. These criteria were an alveolar-postductal arterial oxygen gradient greater than 600 mm Hg for 12 hours or hemodynamic instability. Four of these 7 patients had unremitting hypoxemia after herniorrhaphy (no "honeymoon" period), 3 of whom survived. One additional patient died, producing a mortality of 29%. ECMO used for 68 to 241 hours (mean, 163 hours) provided reliable oxygenation in all. Deaths resulted from disseminated intravascular coagulation and bleeding, and bleeding and pulmonary failure after ligation of a patent ductus arteriosus. Complications occurred in 6 patients and included bleeding (3), hernia recurrence (3), and air embolism (1). Follow-up ranging from 1 year to 6 years after discharge of the 5 survivors shows normal growth and development in 4. The reported mortality without ECMO following congenital diaphragmatic herniorrhaphy in the first 8 hours of life ranges between 60 and 80%. While bleeding may present problems, survival of newborns with refractory hypoxemia after diaphragmatic repair has improved with ECMO.

Extracorporeal Circulation↗
PubMed1987

Mortality with extracorporeal membrane oxygenation following repair of congenital diaphragmatic hernia in 93 infants.

The results of extracorporeal membrane oxygenation (ECMO) following repair of congenital diaphragmatic hernia (CDH) are analyzed for 93 neonates reported to the Neonatal ECMO Registry. Each infant was symptomatic at birth and developed life-threatening hypoxemia after herniorrhaphy. ECMO was used after neonates met criteria predictive of death in individual centers. These included (1) failure of medical therapy to reverse hypoxemia (35 neonates); (2) acute clinical deterioration making death appear likely (37 neonates); (3) AaDO2 greater than 600 for 8 hours (13 neonates); (4) oxygen index score of 51 for 4.8 hours (5 neonates); and (5) cardiac arrest (1 neonate). With ECMO, 52 infants (58%) survived and were discharged. Pre-ECMO arterial blood gas analysis was not predictive of outcome. Mortality was higher in small premature infants. ECMO corrected the hypoxemia, which usually causes death following congenital diaphragmatic herniorrhaphy. Unfortunately, 47 major bleeding complications occurred with 29 deaths. Therefore, improved survival may depend on new methods designed to prevent bleeding.

Cerebral Hemorrhage↗
PubMed1985

Effect of anticoagulation on the lysis of filter entrapped thromboembolism in dogs.

Resolution of thrombi entrapped in Greenfield vena caval filters is a primary mechanism for maintenance of caval patency with this device following an embolic event. In order to determine if anticoagulation is beneficial in this setting, thrombus was harvested from 65 mongrel dogs with infrarenal IVC thrombosis after phenolization. These thrombi were weighed and embolized into Greenfield filters placed above the renal veins. The infrarenal IVCs were then ligated and the animals allowed to recover. Beginning the first postoperative day, animals were given either oral coumadin daily to elevate the prothrombin time above 1.5 normal, subcutaneous heparin 500 u/kg/day divided into two doses, or received no treatment. They were sacrificed either 1, 2, 3, or 4 weeks after embolism and the residual thrombi weighed. Initial thrombus weights were similar for each period (differences NS). Comparison of initial with final weights revealed that both coumadin and heparin-treated animals had a significantly increased resolution in the first week when compared to controls. By 2 weeks, however, there were no significant differences between the groups, and controls proceeded to a mean of 95% resolution by 4 weeks. A general linear model used to separate the effects of treatment, time, and initial thrombus weight showed that resolution was primarily a function of initial thrombus weight, and of time. Coumadin was marginally beneficial. Thrombus resolution proceeds rapidly in this model without anticoagulation. These data suggest that prevention of deep vein thrombosis and its sequelae remain the sole indication for anticoagulation after filter placement.

Administration, Oral↗
PubMed1985

Experimental superior vena caval placement of the Greenfield filter.

Pulmonary embolism (PE) from sources superior to the right atrium has been documented in several reports, but mechanical device protection has not been advised because of the morbidity associated with occlusion of the superior vena cava (SVC). Mechanical protection must maintain caval patency, protect against recurrent PE, and be safe. Since the Greenfield filter has fulfilled these criteria when placed in the inferior vena cava (IVC), we tested its suitability for use in the SVC in 11 dogs. Thrombus was harvested from phenolized segments of infrarenal vena cava and embolized into filters positioned in the SVC through the jugular or brachiocephalic vein under fluoroscopic guidance. Central venous pressure (CVP) was monitored before and after embolization. The dogs were allowed to recover and were followed up with monthly vena caval contrast studies and CVP measurements. After 3 months the animals were put to death and autopsies performed to determine the size of any residual thrombus and to examine the pulmonary arteries for signs of PE. Ten dogs had correct placement of the filter in the SVC; there were no perforations and no episodes of PE. CVP rose slightly after embolization into the filter but caval patency was maintained in all animals. Resolution of filter-entrapped thrombi occurred in all animals (mean initial weight = 1.02 gm, mean final weights = 0.11 gm, p less than 0.05). In the eleventh animal the filter was discharged high, with one leg perforating the brachiocephalic vein. No hemorrhage or distal embolism occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Malignant fibrous histiocytoma of the breast. A case report and review of the literature.

The clinicopathologic features of a malignant fibrous histiocytoma arising in a female breast are presented. Seven cases have been previously reported. These may be divided into three subgroups based on history and pathologic findings. Three of the seven occurred in women without a history of other tumors or previous irradiation. One appeared with a cystosarcoma phyllodes, and three arose following radiation for carcinoma of the breast. The patient in this study had received no radiation. Treatment has been based on surgical resection; the roles of chemotherapy and radiation are uncertain. Although resection alone in the first subgroup has lead to no reported mortality, the small number of cases and the relatively short follow-up does not allow a meaningful assessment of the prognosis in this disease.

Biopsy, Needle↗
PubMed1984

Surgical approaches to thromboembolism.

Management of angiographically confirmed pulmonary thromboembolism in 313 patients has been based on a physiological classification system. Patients in shock (Class IV) are managed either by catheter embolectomy (26 patients) with 27 per cent mortality rate or by open embolectomy during active resuscitation (6 patients) with a 33 per cent mortality rate. High-risk patients with transient hypotension (Class III) are managed by anticoagulation and filter insertion. The most common indication for filter placement is a contra-indication to anticoagulation (37 per cent). Filter placement was infrarenal in 268 patients (86 per cent) and intentionally suprarenal in 19 patients (6 per cent). Misplacement has occurred into the iliac veins, renal veins and the heart but has not been seen since the guide wire technique for insertion was developed. The 30 day mortality for patients receiving filters was 14 per cent and due to other disorders. Only one death was suspected from recurrent embolism. One hundred and thirteen venacavagrams at intervals up to 99 months in 110 patients showed long-term patency in 97 per cent. Recurrent embolism was seen in five patients (2 per cent) but caused no deaths.

Aged↗