Effects of intra-ischemic blood pressure on outcome from 2-vessel occlusion forebrain ischemia in the rat.

Halothane anesthetized Sprague-Dawley rats underwent 10 min of bilateral carotid artery occlusion with mean arterial pressure (MAP) held at 30, 50 or 60 mmHg. Sham rats did not undergo ischemia. A 7-day recovery interval was allowed. Intra-ischemic electroencephalographic (EEG) changes, behavioral function (Days 5-7), and histologic injury (Day 7) were evaluated. Under similar conditions, cerebral blood flow was determined after 10 min ischemia by the [3H]nicotine indicator fractionation technique. EEG isoelectricity was observed in 11 of 11, 5 of 10, and 2 of 11 rats in the 30 mmHg, 50 mmHg, and 60 mmHg groups respectively. Neither passive avoidance cross-over latencies nor general motor scores were affected by intra-ischemic MAP and no differences from sham performance were observed. The per cent of CA1 neurons counted as dead (left and right hemispheres combined) was significantly affected by intra-ischemic MAP (72, 46 and 28% in the 30 mmHg, 50 mmHg, and 60 mmHg groups, respectively; P less than 0.001). A greater than 50% CA1 neuronal mortality rate was present only in those rats exhibiting EEG isoelectricity. However, the number of rats demonstrating greater than a 25% interhemispheric difference in CA1 neuronal loss was greatest in the 50 mmHg group (P less than 0.02). Hippocampal blood flow decreased in association with severity of hypotension (8 +/- 1, 35 +/- 8, and 48 +/- 2 ml/100 g/min (mean +/- S.E.M.) for 30, 50, and 60 mmHg, respectively; P less than 0.01). Again, however, the greatest variability in blood flow was observed at MAP = 50 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)     

Interventions to promote optimal health outcomes in children with Type 1 diabetes—are they effective?

The incidence of Type 1 diabetes is increasing worldwide, imposing enormous public health costs, as well as profoundly affecting individual quality of life. There is evidence that psychological problems are increased in children with diabetes and this morbidity is often associated with poor metabolic control. Specific risk factors for this dual morbidity are emerging from empirical studies. The next challenge is to identify effective interventions for use with children at risk for adverse mental and physical health outcomes. The intervention literature is reviewed. It is noted that most studies have used diabetes-specific, unstandardized interventions in groups of adolescents, with few interventions trialled with younger children. No study has targeted a specific psychological disorder such as behaviour problems or depression, both of which are known to be increased in children with diabetes and for which effective standardized interventions are available. Attention is drawn to methodological limitations in many of the studies conducted to date and suggestions made to reduce these in future interventions attempting to reduce the burden of illness in children with diabetes.     

Nitrous oxide withdrawal reduces intracranial pressure in the presence of pneumocephalus

Nitrous oxide anesthesia has been implicated as contributing to the development of delayed tension pneumocephalus following surgery performed in the sitting position. The authors tested the hypothesis that withdrawal of nitrous oxide anesthesia administered during formation of an intracranial gas cavity would lead to a decrease in intracranial pressure (ICP) as N2O diffuses from the cavity back into the blood. Ten halothane-anesthetized rabbits were prepared for measurement of supracortical ICP and arterial blood pressure (BP) and for intracranial volume alterations via a cisterna magna infusion catheter. Hyperventilation (Paco2 = 28-30 mmHg) and mannitol were used to shrink the brain to accommodate intracranial infusion of either air or lactated Ringer's (LR) solution, which was used to elevate ICP to between 10-15 mmHg from a baseline ICP of 2.1 +/- 2.5 mmHg over a period of 8 to 10 min. Following stabilization at an elevated ICP, inhalation of nitrous oxide (75%) was either initiated or withdrawn (if already present during the induced ICP increase) and the subsequent changes in mean ICP and BP were recorded. Following ICP elevation with LR to 10 +/- 1 mmHg, initiation of 75% N2O administration resulted in no change in ICP and modest increases (P less than 0.05) in BP and cerebral perfusion pressure (CPP = BP - ICP) after 4 min. However, when ICP was raised (to 12 +/- 3.5 mmHg) with intracranial air infusion, subsequent initiation of 75% N2O inhalation caused an abrupt ICP increase to 22.3 +/- 9 mmHg (from control P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Combined open and laparoscopic approach to chronic pain following open inguinal hernia repair

Introduction: Chronic groin pain is the most common long-term complication after open inguinal hernia repair. Traditional surgical management of the associated neuralgia consists of injection therapy followed by groin exploration, mesh removal, and nerve transection. The resultant hernia defect may be difficult to repair from an anterior approach. We evaluate the outcomes of a combined laparoscopic and open approach for the treatment of chronic groin pain following open inguinal herniorrhaphy. Methods: All patients who underwent groin exploration for chronic neuralgia after a prior open inguinal hernia repair were prospectively analyzed. Patient demographics, type of prior hernia repair, and prior nonoperative therapies were recorded. The operation consisted of a standard three trocar laparoscopic transabdominal preperitoneal hernia repair, followed by groin exploration, mesh removal, and nerve transection. Outcome measures included recurrent groin pain, numbness, hernia recurrence, and complications. Results: Twelve patients (11 male and 1 female) with a mean age of 41 years (range 29–51) underwent combined laparoscopic and open treatment for chronic groin pain. Ten patients complained of unilateral neuralgia, one patient had bilateral complaints, and one patient complained of orchalgia. All patients failed at least two attempted percutaneous nerve blocks. Prior repairs included Lichtenstein (n=9), McVay (n=1), plug and patch (n=1), and Shouldice (n=1). There were no intraoperative complications or wound infections. With a minimum of 6 weeks follow up, all patients were significantly improved. One patient complained of intermittent minor discomfort that required no further therapy. Two patients had persistent numbness in the ilioinguinal nerve distribution but remained satisfied with the procedure. Conclusions: A combined laparoscopic and open approach for postherniorrhaphy groin pain results in good to excellent patient satisfaction with no perioperative morbidity. It may be the preferred technique for the definitive management of chronic neuralgia after prior open hernia repair.     

Incidence of Finding Residual Disease for Incidental Gallbladder Carcinoma: Implications for Re-resection

Re-resection for gallbladder carcinoma incidentally discovered after cholecystectomy is routinely advocated. However, the incidence of finding additional disease at the time of re-resection remains poorly defined. Between 1984 and 2006, 115 patients underwent re-resection at six major hepatobiliary centers for gallbladder carcinoma incidentally discovered during cholecystectomy. Data on clinicopathologic factors, operative details, TNM tumor stage, and outcome were collected and analyzed. Data on the incidence and location of residual/additional carcinoma discovered at the time of re-resection were also recorded. On pathologic analysis, T stage was T1 7.8%, T2 67.0%, and T3 25.2%. The median time from cholecystectomy to re-resection was 52 days. At the time of re-resection, hepatic surgery most often consisted of formal segmentectomy (64.9%). Patients underwent lymphadenectomy (LND) (50.5%) or LND + common bile duct resection (43.3%). The median number of lymph nodes harvested was 3 and did not differ between LND alone (n = 3) vs LND + common duct resection (n = 3) (P = 0.35). Pathology from the re-resection specimen noted residual/additional disease in 46.4% of patients. Of those patients staged as T1, T2, or T3, 0, 10.4, and 36.4%, respectively, had residual disease within the liver (P = 0.01). T stage was also associated with the risk of metastasis to locoregional lymph nodes (lymph node metastasis: T1 12.5%; T2 31.3%, T3 45.5%; P = 0.04). Cystic duct margin status predicted residual disease in the common bile duct (negative cystic duct, 4.3% vs positive cystic duct, 42.1%) (P = 0.01). Aggressive re-resection for incidental gallbladder carcinoma is warranted as the majority of patients have residual disease. Although common duct resection does not yield a greater lymph node count, it should be performed at the time of re-resection for patients with positive cystic duct margins because over one-third will have residual disease in the common bile duct. Presented at the 48th Annual Meeting of the Society for Surgery of the Alimentary Tract at Digestive Week 2007, Plenary Session, Washington, DC, March 23, 2007.     

Optimal metabolite curve fitting for kinetic modeling of 11C-WAY-100635.

Many quantitative imaging protocols that make use of a metabolite-corrected arterial input function require the use of a mathematic model to describe the rate of metabolism of the radioligand. Commonly, parametric models are fit to metabolism data and then the fitted model is used to correct the plasma input function. (11)C-WAY 100635 is a rapidly metabolized radioligand used extensively in mapping the 5-hydroxytryptamine receptor 1A system. METHODS: To evaluate the adequacy of fit of 4 metabolite models, we examined data from 92 subjects who received an injection of (11)C-WAY 100635, were imaged with PET, and underwent measurement of total plasma concentration and metabolites. The performance of these models was assessed according to residual plots, as well as fit and information criteria. RESULTS: The study showed that the choice of model has a substantial effect on the resulting estimates of outcome measures. CONCLUSION: Among the models considered, the Hill model provides the best fit across all criteria.     

Heart failure survival score continues to predict clinical outcomes in patients with heart failure receiving β-blockers

BACKGROUND: The Heart Failure Survival Score (HFSS) has been previously shown to effectively risk-stratify patients under evaluation for heart transplantation. However, this model was developed before broad use of beta blockade. We hypothesized that the prognostic tool would retain its ability to risk stratify patients treated with beta-blockers. METHODS: We collected clinical data on 524 consecutive patients referred for heart transplantation from 1994 to 2001. Kaplan-Meier survival analysis and multivariable Cox regression analysis were performed with events defined as death, left ventricular assist device placement, or United Network of Organ Sharing 1 heart transplantation. RESULTS: Kaplan-Meier analysis of the patient population revealed effective discrimination by the survival score both for beta-blocker treated and untreated patients (both p <0.0001). Two-year event-free survival was 94% +/- 2% and 84% +/- 4% for beta-blocker and no beta-blocker patients in the low-risk HFSS strata. Cox proportional hazard modeling showed that HFSS strata (medium risk: HR 2.65, 95% CI 1.75-4.02, p <0.001; high risk: HR 5.51, 95% CI 3.64-8.33, p <0.001) and beta-blocker treatment (HR 0.45, 95% CI 0.31-0.64, p <0.001) were significant predictors of event-free survival. Receiver operating curves (area under the curve) for HFSS strata used to predict 2-year events were similar for beta-blocker treated (0.78 +/- 0.04) and untreated (0.80 +/- 0.03) patients. CONCLUSIONS: The HFSS provides effective risk stratification with or without beta-blocker therapy. Consideration of beta-blocker therapy with survival score strata improves outcome prediction in patients evaluated for heart transplantation.