Obstructive sleep apnoea and perioperative complications in bariatric patients.

BACKGROUND: The objective of this study was to determine the relationship between perioperative complications and the severity of obstructive sleep apnoea (OSA) in patients undergoing bariatric surgery who had undergone preoperative polysomnography (PSG). METHODS: The records of 797 patients, age >18 yr, who underwent bariatric operations (442 open and 355 laparoscopic procedures) at Mayo Clinic and were assessed before operation by PSG, were reviewed retrospectively. OSA was quantified using the apnoea-hypopnoea index (AHI) as none (≤ 4), mild (5-15), moderate (16-30), and severe (≥ 31). Pulmonary, surgical, and 'other' complications within the first 30 postoperative days were analysed according to OSA severity. Logistic regression was used to assess the multivariable association of OSA, age, sex, BMI, and surgical approach with postoperative complications. RESULTS: Most patients with OSA (93%) received perioperative positive airway pressure therapy, and all patients were closely monitored after operation with pulse oximetry on either regular nursing floors or in intensive or intermediate care units. At least one postoperative complication occurred in 259 patients (33%). In a multivariable model, the overall complication rate was increased with open procedures compared with laparoscopic. In addition, increased BMI and age were associated with increased likelihood of pulmonary and other complications. Complication rates were not associated with OSA severity. CONCLUSIONS: In obese patients evaluated before operation by PSG before bariatric surgery and managed accordingly, the severity of OSA, as assessed by the AHI, was not associated with the rate of perioperative complications. These results cannot determine whether unrecognized and untreated OSA increases risk.

Endoscopic ultrasound rendezvous for bile duct access using a transduodenal approach: cumulative experience at a single center. A case series.

Endoscopic ultrasound (EUS)-assisted biliary access is utilized when conventional endoscopic retrograde cholangiopancreatography (ERCP) fails. We report a 10-year experience utilizing a transduodenal EUS rendezvous via a transpapillary route without dilation of the transduodenal tract, followed by immediate ERCP access. Patients included all EUS-guided rendezvous procedures for biliary access that were performed following ERCP failure. EUS-assisted bile duct puncture was performed via a transduodenal approach and a guide wire was advanced through the papilla without any dilation or bougienage of the tract; ERCP was performed immediately afterwards. EUS-assisted biliary rendezvous was attempted in 15 patients (mean age 66 +/- 18.2 years; malignant = 10, benign = 5). Mean diameter of measured bile ducts was 14.3 +/- 5.17 mm (range 4-23 mm). The reasons for initial ERCP failure were tumor infiltration or edema (n = 9), intradiverticular papilla (n = 2), pre-existing duodenal stent (n = 1), and anatomic anomalies (n = 3). Successful EUS-guided bile duct puncture and wire passage were achieved in all 15 patients (100 %), with drainage being successful in 12 / 15 (80 %). Failures occurred in three patients due to inability to traverse the biliary stricture (n = 2) or dissection of a choledochocele with the guide wire (n = 1); all were subsequently drained via percutaneous methods. Stents placed were metallic in eight patients and plastic in four. Complications consisted of moderate pancreatitis after a difficult ERCP attempt in one patient, and bacteremia after percutaneous biliary drainage in another. There were no instances of perforation, extraluminal air or fluid collections. EUS-assisted biliary drainage utilizing a transduodenal rendezvous approach demonstated a high success rate without any complications directly attributable to the EUS access. Advantages over percutaneous biliary and other methods of EUS biliary access include performance under the same anesthesia, and a very small-caliber needle puncture similar to EUS/fine-needle aspiration.

Recent advances and novel methods in pancreatic imaging.

Traditional imaging studies for evaluating pancreatic disease including abdominal ultrasound (US) and computerized tomography (CT) are widely utilized due to their availability, non-invasiveness, and familiarity to practitioners. The addition of endoscopic ultrasound (EUS) and magnetic resonance imaging (MRI) and magnetic resonance cholangiopancreatography (MRCP) has contributed significantly to the clinician's the ability to safely sample tissue, stage malignancy, evaluate the pancreatic ductal anatomy, and look for subtle parenchymal changes in the setting of chronic pancreatitis. The role of endoscopic retrograde cholangiopancreatography (ERCP) has diminished with the use of these less invasive modalities. Limitations in these conventional techniques include a lack of sensitivity and specificity in diagnosing early chronic pancreatitis, difficulties in differentiating malignancy from chronic or focal pancreatitis, and accuracy of staging pancreatic malignancy, particularly with regard to vascular involvement. Several recent advances in traditional imaging techniques have been described, which may improve our ability to accurately diagnose and stage pancreatic disease. Advances have been made in the standard modalities for imaging the pancreas such as multidetector CT, micro-bubble contrast enhanced ultrasound, and secretin stimulated MRCP. Other novel methods of pancreatic imaging have recently been described including EUS elastography, optical coherence tomography, diffusion weighted MRI, and MR spectroscopy. This article will review the recent advances in both traditional pancreatic imaging modalities as well as some of the emerging technologies for imaging evaluating diseases of the pancreas. As experience and clinical evidence accumulate, the role of these imaging techniques will continue to evolve.

Transjugular liver biopsy after transjugular intrahepatic portosystemic shunt (TIPS) or direct intrahepatic portocaval shunt (DIPS): Is it feasible, effective, and safe?

PURPOSE: To evaluate our experience with transjugular liver biopsies (TJLB) in patients with previously placed transjugular intrahepatic portosystemic shunt (TIPS) or direct intrahepatic portocaval shunt (DIPS). MATERIAL AND METHODS: A single-institution retrospective review was performed looking at all TJLBs in patients with previously placed TIPS or DIPS over the past seven years. There were six men and one woman (mean age 57.9±8.8 [SD] years; range: 47-71 years). Patient demographics, indications, procedural details, laboratory data, complications, and pathology were recorded. Patients with occluded TIPS were excluded from this study. RESULTS: Seven TJLBs were performed, five in patients who had a TIPS and two who had a DIPS. Of the patients with TIPS, biopsies were performed from the same hepatic vein as TIPS in three procedures and from a different hepatic vein in two procedures. In DIPS patients, both biopsies were performed from the right hepatic vein. The reasons for the transjugular rather than the percutaneous approach to liver biopsy included ascites, coagulopathy, or need for concurrent TIPS/DIPS evaluation and/or revision. All procedures were technically successful with adequate samples obtained. There were no immediate or delayed complications. CONCLUSION: Our results suggest that if needed a TJLB can safely and effectively be performed in patients with previously placed TIPS or DIPS.

S-adenosylhomocysteine catabolism and basis for acquired resistance during treatment of T-cell acute lymphoblastic leukemia with 2'-deoxycoformycin alone and in combination with 9-beta-D-arabinofuranosyladenine.

A patient with refractory T-cell acute lymphoblastic leukemia was treated with eight courses of the adenosine deaminase inhibitor, 2'-deoxycoformycin (dCF), over a 5-month period. After developing resistance to dCF, he responded to treatment with the combination of dCF and 9-beta-D-arabinofuranosyladenine (ara-A). We monitored the levels in plasma and urine of adenosine, 2'-deoxyadenosine, and ara-A as well as the accumulation of their nucleotide derivatives in erythrocytes and circulating lymphoblasts. We also monitored the activities of adenosine deaminase and S-adenosylhomocysteine (AdoHcy) hydrolase and the concentrations of AdoHcy and S-adenosylmethionine in lymphoblasts. Production of 2'-deoxyadenosine was related to both the duration of dCF infusion and the magnitude of cytolysis that occurred during treatment: much more 2'-deoxyadenosine was produced by dCF infusion when disease was active than by the same infusion given during remission. Resistance to dCF was associated with a decrease of greater than 90% in the amount of deoxyadenosine 5'-triphosphate accumulated by circulating lymphoblasts. Infusion of dCF resulted in increases of up to 20-fold in the concentration of AdoHcy in circulating lymphoblasts, causing a decrease in the S-adenosylmethionine:AdoHcy ratio (the "methylation index") from a pretreatment value of greater than 40:1 to less than 4:1. This ratio decreased to 2.5:1 during combined treatment with dCF and ara-A, which caused nearly complete inactivation of lymphoblast AdoHcy hydrolase. Decline in the methylation index was accompanied by inhibition of the methylation of newly synthesized lymphoblast RNA. Impaired ability to catabolize AdoHcy may have contributed to the cytolytic responses to dCF and ara-A, as well as to hepatic and central nervous system toxicity associated with their combined use.

Frequency-Dependent Selection for Plasmid-Containing Cells of ESCHERICHIA COLI.

Colicin-producing plasmid-containing cells of E. coli exhibit frequency-dependent selection when grown in glucose-limited continuous culture with the corresponding plasmid-free strain. The bases of this frequency-dependent effect are shown to be (1) the lower growth rate of the plasmid-containing strain under these conditions, and (2) the production of colicin, which attenuates the growth rate of the plasmid-free strain. These results are discussed in relationship to the maintenance of genetic variation in prokaryotes.

The role of endoscopic retrograde cholangiopancreatography and endoscopic ultrasound in diagnosis and treatment of acute pancreatitis.

Endoscopic retrograde cholangiopancreatography (ERCP) is an important tool for diagnosis and therapy in acute and recurrent pancreatitis. While treatment of biliary disorders leading to pancreatitis is common practice, over the past several years many specialized centers have been directing traditional biliary techniques such as sphincterotomy and stenting towards the pancreas. A justifiable fear of pancreatitis and other complications has caused many endoscopists to shy away from pancreatic endotherapy, but refinements in technique, extensive experience, and most notably the routine use of pancreatic stenting to prevent post-ERCP pancreatitis has opened up the field and allowed for endoscopists in specialized centers around the world to perform diagnostic and therapeutic ERCP of the pancreas safely and effectively. In acute gallstone pancreatitis, the benefit of therapeutic ERCP including biliary sphincterotomy has been proven in randomized controlled trials. There are also data to support the role of ERCP directed at the pancreatic sphincters and ducts in treatment of acute relapsing pancreatitis due to pancreas divisum, sphincter of Oddi dysfunction, smoldering pancreatitis, pancreatic ductal disruptions, and perhaps even in evolving pancreatic necrosis. Many causes of apparently idiopathic pancreatitis can be discovered after an extensive evaluation with endoscopic ultrasound (EUS), magnetic resonance cholangiopancreatography (MRCP) and ERCP with sphincter of Oddi manometry. ERCP often allows treatment of the underlying cause. Because of the inherent risks associated with ERCP, particularly when directed toward the pancreas, the role of ERCP in acute and especially recurrent pancreatitis should be primarily therapeutic with attempts to establish diagnosis whenever possible by less risky techniques including EUS and MRCP. With the added techniques, devices, skill-sets, and experience required, pancreatic endotherapy should preferably be performed in high volume tertiary referral settings. ERCP for diagnosis and treatment of severe or acute relapsing pancreatitis is also best performed using a multidisciplinary approach involving endoscopy, hepatobiliary-pancreatic surgery, and interventional radiology.

Therapeutic considerations in childhood idiopathic thrombocytopenic purpura.

This monograph reviews the literature regarding therapy for childhood idiopathic thrombocytopenic purpura (ITP). The role and mechanism of action are discussed for corticosteroids, splenectomy, and intravenous gamma globulin. Alternative therapies with potent immunosuppressive agents are also mentioned. Guidelines for the management of children with ITP are presented.

Immunopathology of childhood idiopathic thrombocytopenic purpura.

Modern laboratory techniques have begun to elucidate the pathophysiology of chronic childhood ITP. Quantitative assays of PAIgG, complement, immune complexes, and platelet kinetic studies have all provided important information. Chronic ITP of childhood appears to be similar to adult ITP, with production of an antibody directed against platelets and megakaryocytes. Most of the antibody is produced in the spleen, but other parts of the RES can also produce antibody. Complement, immune complexes, and cell-mediated immunity may play a role in the pathogenesis. Sensitized platelets are cleared by the RES, particularly in the spleen. Platelet kinetic studies show that platelet turnover is usually rapid with compensatory increased thrombopoiesis, but there are some patients who have decreased thrombopoiesis. Acute ITP of childhood is a brief illness, characterized by abrupt onset of hemorrhagic symptoms and complete recovery. It often follows a viral illness, suggesting that immune complexes as well as antibodies are important in the pathogenesis. Both the spleen and liver may be important organs of immune clearance.

Treatment of platelet alloimmunization with intravenous immunoglobulin. Two case reports and review of the literature.

Two pediatric patients with severe aplastic anemia, elevated antiplatelet antibody levels, refractoriness to human lymphocyte antigen-matched platelet transfusions, and sustained bleeding problems were treated with intravenous immunoglobulin (IVIG), pH 4.25, for three to over nine months. Improved responses to platelet infusions and improved hemostasis were demonstrated in both patients. A review of the published literature analyzing the role of IVIG in the treatment of platelet alloimmunization is presented.

Efficacy of intravenous gamma globulin in autoimmune-mediated pediatric blood dyscrasias.

Sixteen pediatric patients diagnosed with a variety of autoimmune-mediated hematocytopenias were treated with one to 50 courses of intravenous gamma globulin (IVIG), pH 4.25, over the course of one to 30 months. Thirteen patients had immune thrombocytopenic purpura (ITP), two had autoimmune neutropenia, and one had autoimmune hemolytic anemia. In one patient, chronic ITP was associated with systemic lupus erythematosis, and in a second patient, acute ITP was the presenting manifestation of infection with human immunodeficiency virus. Initial therapy consisted of 400 mg/kg/dose daily for five days for the first seven patients treated, and 1,000 mg/kg/dose daily for two days for the remaining nine patients. In 15 of 16 patients, there was a response to IVIG therapy. In nine of 16 patients, maintenance IVIG therapy for two to more than 30 months was required. Minimal toxicity was experienced in four of 210 separate infusions. Data are presented to support the use of IVIG in the management of childhood autoimmune disorders.

Venous thrombosis in a family with defective release of vascular plasminogen activator and elevated plasma factor VIII/von Willebrand's factor.

A family is described in which venous thrombosis developed in five members as early as 14 years of age. Routine coagulation studies, plasma antithrombin III, factor V, plasminogen, beta-thromboglobulin, fibrinopeptide A, prothrombin fragment F1+2, and thrombin-antithrombin III complex were all within normal limits. However, defective release of vascular plasminogen activator was observed on several occasions in all five subjects as compared with a control population of 125 persons (0.04 Committee on Thrombolytic Agents [CTA] units/ml plasma as compared with 0.21 CTS units/ml). In addition, levels of factor VII/von Willebrand's factor were significantly elevated above the normal range in this pedigree.

Mortality in children and adolescents with sickle cell disease. Cooperative Study of Sickle Cell Disease.

A study of the natural history of sickle hemoglobinopathies was begun in March 1979. By August 1987, a total of 2824 patients less than 20 years of age were enrolled. There have been 14,670 person-years of follow-up. Seventy-three deaths have occurred. Most of the deaths were in patients with hemoglobin SS. The peak incidence of death was between 1 and 3 years of age, and the major cause in these young patients was infection. Cerebrovascular accidents and traumatic events exceeded infections as a cause of death in patients greater than 10 years of age. There was limited success in identifying risk factors for death. Comparison of this study's overall mortality of 2.6% (0.5 deaths per 100 person-years) with previous reports indicates improvement of survival in US patients less than 20 years of age with sickle hemoglobinopathies. This improvement is most likely due to parental education and counseling about the illness and the early institution of antibiotics in suspected infections.

Current status of dilatation catheters and guiding systems.

New transluminal angioplasty catheters based upon the linear extrusion of the dilating element have been developed to facilitate placement of the dilating balloon within the arterial narrowing. In a multicenter study, the use of linear extrusion catheters has been shown to be safe and effective in adjunctive intraoperative peripheral dilatations. Physical measurements of the frictional forces exerted on the inner arterial surfaces during advancement of 3 angioplasty catheter designs show that the linear extrusion catheter consistently minimizes these forces. The use of a secondary guiding sheath in conjunction with a linear extrusion catheter provides additional directional capability. A secondary guiding sheath with a side port has recently been developed that allows access to difficult-to-cannulate vessels. The favorable results of the clinical studies and research data justify an ongoing evaluation of these concepts in percutaneous dilatation procedures and in intraoperative coronary procedures.

Agricultural production systems and environmental health.

By the turn of the century, American farmers and ranchers will be producing food and fiber through the application of highly sophisticated systems that involve a broad spectrum of relevant factors--from soil type, to options for fertilizer and pesticide use, to markets and other economic information. These systems will help farmers and ranchers better match land use to land capability, apply needed conservation practices, make environmentally sound production choices, and lower production costs. Most importantly, they will aid in selecting the best combinations of chemical and the biological means for producing and protecting plants and animals. The systems will also help complement currently available and new classes of chemicals with biological control mechanisms such as natural predators and naturally occurring protective phenomena such as allelopathy and other forms of resistance to insects, weeds, and disease. Additionally, they will incorporate the use of biodegradable, slow-release, or timed-release natural and synthetic pest control materials. Also, scientists will increasingly emphasize nutrition and food safety in the development of plant and animal germplasm and production and processing methods.

The impact of an elective curriculum in pathology.

Under the revised medical curriculum at Duke University, elective courses were offered in the third and fourth years beginning in 1968-1969. Departmental electives in autopsy, surgical, and systemic pathology were offered as major courses, and the subspecialty courses in cardiovascular, renal, pulmonary, pediatric, and neuropathology were taught by specialists in those areas. Special topics in subcellular and molecular pathology, neoplasia, environmental diseases, and experimental pathology were subscribed by medical and graduate students alike. To determine the impact of elective courses in pathology, these electives were compared to those offered by other basic science disciplines. Tabulation of total courses offered, student enrollment, and total academic credit hours were constructed for each basic science area. The data show that over the six year study period the students elected more courses in pathology than in any other basic science. The most heavily subscribed electives in pathology were those that were clinically oriented, such as cardiovascular or renal pathology. One impact of this elective system may be to enhance recruitment. During the period studied, 29 Duke graduates interned in pathology compared to six under a comparable time period in the traditional curriculum.

Validity of cardiac output measurement by the thermodilution method in the presence of acute tricuspid regurgitation.

Evaluation of patients with acute tricuspid insufficiency may include assessment of cardiac output by the thermodilution method. The accuracy of estimates of thermodilution-derived cardiac output in the presence of tricuspid insufficiency has been questioned. This study was designed to determine the validity of the thermodilution technique in a canine model of acute reversible tricuspid insufficiency. Cardiac output as measured by thermodilution and electromagnetic flowmeter was compared at two grades of regurgitation. The relationship between these two methods (thermodilution/electromagnetic) changed significantly from a regression slope of 1.01 +/- 0.18 (mean +/- standard deviation) during control conditions to a slope of 0.86 +/- 0.23 (p < 0.02) during severe regurgitation. No significant change was observed between control and mild regurgitation or between the initial control value and a control measurement repeated after tricuspid insufficiency was reversed at the termination of the study. This study shows that in a canine model of severe acute tricuspid regurgitation the thermodilution method underestimates cardiac output by an amount that is proportional to the level of cardiac output and to the grade of regurgitation.

Successful treatment of varicella pneumonia with prolonged extracorporeal membrane oxygenation in a child with leukemia.

A 5-year-old boy with acute lymphoblastic leukemia in complete continuous remission developed life-threatening varicella pneumonia and acute respiratory insufficiency (ARI). The child recovered after 92 hours of partial venoarterial perfusion with a membrane oxygenator. Functional asplenia developed. Serial pulmonary function tests after perfusion indicate moderately severe restrictive lung disease which has slightly improved during an 18 month period.

Clinical comparisons of methods of myocardial protection.

Currently, numerous methods are in use for myocardial hypothermia as a myocardial preservation modality for cardiac operations. During cardiac ischemia we have compared myocardial surface cooling with topical cold saline (Group I, N = 9), crystalloid cardioplegia plus topical cold saline (Group II, N = 8) and cardioplegia with a specially designed cooling jacket (Group III, N = 8) in patients undergoing aortic or mitral valve replacement, or both. Temperatures were assessed and recorded continuously in standardized locations for the right and left ventricular epicardium and endocardium. In Group I the rate of cooling was significantly slower than in the other two groups. Also, excessive gradients were developed across the left and right ventricular walls. In Group II the rate and depth of cooling were adequate and initial temperature gradients were eliminated. However, over the period of ischemia, significant rewarming occurred. In Group III temperatures were reduced rapidly and uniformly and maintained at or below 10 degrees C for the duration of the ischemic period. These differences are statistically significant (p less than 0.05). For optimal myocardial hypothermia, we recommend the following: separate cannulation of the superior and inferior venae cavae with caval snares; venting of the pulmonary artery (if inadequate, pulmonary vein occlusion or direct left atrial venting); induction of myocardial hypothermia with crystalloid or cold blood cardioplegia; and maintenance of hypothermia by the cooling jacket described herein. It is also desirable to continuously monitor temperatures of the right and left ventricular endocardial and epicardial surfaces.

Reversibility of cardiac xenograft rejection in primates.

More than 500 people died in 1988 because of the shortage of human heart donors. Cardiac xenografts from concordant primates may help to relieve this shortage. Two groups of ABO-matched cynomolgus monkey-to-baboon heterotopic cardiac xenografts were studied. Group 1 (n = 4) control animals had no immunosuppression. Group 2 (n = 6) baboons received cyclosporine, azathioprine, and methylprednisolone acetate. Myocardial biopsy, mixed lymphocyte culture, donor-specific crossmatch, and panel-reactive antibody determinations were performed after transplantation. Biopsy-proven rejection episodes (myocyte necrosis) were treated intravenously with steroids. A follow-up biopsy was performed 7 days after the first biopsy. If rejection persisted, antithymocyte globulin (10 mg/kg/day) was given for 7 days, and another biopsy was performed. Group 1 (control) graft survival was 8, 9, 9, and 10 days (mean, 9 days). Group 2 (immunosuppressed) graft survival was 3, 16, 18, 51, 84, and 392 days (mean, 94 days). Each immunosuppressed baboons' xenograft had myocyte necrosis and variable degrees of edema, cellular infiltrates, and vascular thrombosis consistent with mixed cellular and humoral rejection within 1 week. Only one rejection episode resolved with high-dose steroid therapy alone. Two baboons' rejection episodes resolved with antithymocyte globulin treatments, but rejection recurred in both. Low levels of or delayed progression of panel-reactive antibody was associated with long-term xenograft survival. Severe steroid-resistant rejection with cell-mediated and humoral immune elements developed early in our primate cardiac xenografts despite triple-drug immunosuppression. Use of antithymocyte globulin was associated with temporary resolution of rejection, but progressive increases in lymphocytotoxic antibody led invariably to eventual graft loss despite rare long-term survival.