Clinical fMRI: evidence for a 7T benefit over 3T.

Despite there being an increasing number of installations of ultra high field MR systems (>3T) in clinical environments, no functional patient investigations have yet examined possible benefits for functional diagnostics. Here we performed presurgical localization of the primary motor hand area on 3T and 7T Siemens scanners with identical investigational procedures and comparable system specific sequence optimizations. Results from 17 patients showed significantly higher functional sensitivity of the 7T system measured via percent signal change, mean t-values, number of suprathreshold voxels and contrast to noise ratio. On the other hand, 7T data suffered from a significant increase of artifacts (ghosting, head motion). We conclude that ultra high field systems provide a clinically relevant increase of functional sensitivity for patient investigations.

Protective effect of BDNF against beta-amyloid induced neurotoxicity in vitro and in vivo in rats.

We examined the potential protective effect of BDNF against beta-amyloid-induced neurotoxicity in vitro and in vivo in rats. In neuronal cultures, BDNF had specific and dose-response protective effects on neuronal toxicity induced by Abeta(1-42) and Abeta(25-35). It completely reversed the toxic action induced by Abeta(1-42) and partially that induced by Abeta(25-35). These effects involved TrkB receptor activation since they were inhibited by K252a. Catalytic BDNF receptors (TrkB.FL) were localized in vitro in cortical neurons (mRNA and protein). In in vivo experiments, Abeta(25-35) was administered into the indusium griseum or the third ventricle and several parameters were measured 7 days later to evaluate potential Abeta(25-35)/BDNF interactions, i.e. local measurement of BDNF release, number of hippocampal hilar cells expressing SRIH mRNA and assessment of the corpus callosum damage (morphological examination, pyknotic nuclei counting and axon labeling with anti-MBP antibody). We conclude that BDNF possesses neuroprotective properties against toxic effects of Abeta peptides.

Routine use of unilateral and bilateral radial arteries for coronary artery bypass graft surgery.

OBJECTIVES: This study sought to evaluate the routine use of radial artery (RA) grafts in patients undergoing coronary artery revascularization. BACKGROUND: Previous long-term studies have documented poor patency of saphenous vein grafts compared with internal thoracic artery (ITA) grafts. METHODS: We performed a prospective review of 175 of 249 consecutive patients. RESULTS: Fifty-four patients had bilateral RAs harvested. Mean number (+/- SD) of grafts/patient was 3.27 +/- 0.93, with 2.76 +/- 0.97 arterial grafts; a mean of 1.53 +/- 0.68 grafts were performed with the RA. The operative mortality rate was 1.6%. No deaths were related to RA grafts, and there were no RA harvest site hematomas or infections. Transient dysesthesia 1 day to 4 weeks in duration occurred in the distribution of the lateral antebrachial cutaneous nerve in six extremities (2.6%). Elective cardiac catheterization in 60 patients at 12 weeks postoperatively demonstrated a 95.7% patency rate. CONCLUSIONS: Because of potential benefit of long-term patency associated with arterial grafts, minimal morbidity and mortality associated with use of the RA and excellent short-term patency rates, we cautiously recommend use of one or both RAs as additional conduits to be used concomitantly with the ITA for arterial revascularization of the coronary arteries.

Teaching rapid sequence intubation to pediatric emergency physicians: a pilot course.

We describe and evaluate a pilot course designed to teach rapid sequence intubation (RSI) to pediatric emergency physicians. A questionnaire was utilized to assess participants' self-assessment of knowledge and skills in defined areas related to rapid sequence intubation, before and after the course. Thirteen pediatric emergency physicians (nine attendings and four fellows) participated in the pilot course. A significant increase in self-assessment of knowledge and skills was found after the course for most parameters analyzed. These areas included: knowledge of indications and contraindications for RSI, knowledge of specific sedating and paralyzing agents, knowledge of complications of RSI and their management, and level of comfort performing RSI when indicated (P < 0.05). We conclude that a formal course can significantly enhance self-assessment concerning ability to perform rapid sequence intubation. Further study is required to determine if such a course improves performance of this procedure.

Impact of specific substrate supply on efficiency of cardiac function: an update.

Investigations of the mechanisms that modulate energy generation during states of altered cardiac metabolism have reached a point where there is both need and demand for novel approaches. The evidence discussed here strongly suggests that both energy generation and utilization in these states may be effectively strengthened by nutritional manipulation. Compared with standard treatments for ischemia/reperfusion injury or heart failure, nutritional therapy may present an important and less toxic approach by affecting the mechanisms of energy utilization during compromised cardiac states. We provide not only a conceptual framework for further experimental studies of myocardial metabolism during ischemia and reperfusion injury but also a basis for developing clinically applicable nutrients designed to improve deranged cardiac function. The use of traditional energy substrates, in conjunction with those that may be conditionally important during compromised cardiac states, potentially offers a useful therapeutic modality in the treatment of the cardiac patient.

Acupuncture anesthesia for open heart surgery: a report of 800 cases.

This article reports the utilization of acupuncture in combination with chemical anesthesia and neuromuscular relaxant for patients with cardiac surgery, including valvular disease and by-pass. In 800 patients studied using this type of combination of anesthetic techniques, it was found that this procedure can be successful for cardiac surgery and that it allows light planes of anesthesia with less interference to circulatory regulation. There is a certain advantage of using acupuncture anesthesia when compared with chemical anesthesia, as the pharmacological agents are not used and hence post no metabolic load for the patients. From the 800 patients studied, it seems justifiable to recommend this anesthetic procedure for cardiac surgery.

The benefits of skull stripping in the normalization of clinical fMRI data.

Establishing a reliable correspondence between lesioned brains and a template is challenging using current normalization techniques. The optimum procedure has not been conclusively established, and a critical dichotomy is whether to use input data sets which contain skull signal, or whether skull signal should be removed. Here we provide a first investigation into whether clinical fMRI benefits from skull stripping, based on data from a presurgical language localization task. Brain activation changes related to deskulled/not-deskulled input data are determined in the context of very recently developed (New Segment, Unified Segmentation) and standard normalization approaches. Analysis of structural and functional data demonstrates that skull stripping improves language localization in MNI space - particularly when used in combination with the New Segment normalization technique.

Postoperative management: ventilation.

The major pulmonary disturbance after pediatric cardiac surgery consists of a loss of lung volume with an increase in extravascular lung water. Therapy is aimed at restitution of functional residual capacity with positive air-way pressure, with or without mechanical ventilation. After major corrective surgery, mechanical ventilation allows the patient to adjust to the altered circulatory physiology while decreasing the work of breathing. The technique of intermittent mandatory ventilation allows a smooth change from ventilatory support to spontaneous respiration.

Incidental finding of papillary fibroelastoma on the atrial septum.

Papillary fibroelastoma is rare but one of the most common benign primary cardiac tumors after myxoma. This lesion may be associated with embolization, angina and sudden death. The incidental finding of a small pedunculated papillary fibroelastoma arising from the atrial septum detected by transesophageal two-dimensional echocardiography (TEE) in a patient undergoing coronary artery bypass grafting is reported. The advantage of TEE in diagnosing intracardiac tumors is also described.

Ketamine for pediatric cardiac anesthesia.

Eighty-five patients ranging from 12 h to 7 years of age were included in this study. In the first group 35 cases received ketamine, gallamine and oxygen for surgery on the great vessels. Ketamine provided satisfactory analgesia and amnesia. Heart rate did not change significantly. Gallamine gave additional safety in the prevention of bradycardia. One hundred per cent oxygen increased oxygen saturation and made more oxygen available for the tissues. The combination secured favorable conditions even in cases of sevre right to left shunt. Seven patients developed some degree of bradycardia, requiring treatment. All but one responded to epinephrime infusion. The one who did not improve died on the table. There were 6 additional deaths during the first 48 postoperative hours. Fifty infants and children received pentobarbital and morphine premedication and ketamine, pancuronium, nitrous-oxide oxygen anesthesia for open heart surgery. Cardiovascular stability with good operating conditions characterized the course of anesthesia. The increase in systolic and diastolic blood pressures and heart rate was small after induction. Further changes in these parameters during anesthesia were statistically insignificant. Perfusion pressure during cardio-pulmonary bypass was well maintained. The addition of 50 per cent nitrous oxide to inhaled oxygen significantly potentiated the duration of hypnosis and analgesia proved by ketamine. Mechanical ventilation was facilitated in both groups by the analgesia extending well into the postoperative period. There were 6 deaths in the first 48 postoperative hours in this group. The state of consciousness at the end of anesthesia and postoperative conditions of all 85 patients were comparable with that found with other agents. The techniques described provided suitable alternatives to the anesthetic management pediatric cardiac surgery.

An alternative oxygen delivery system for infants and children in the post-anaesthesia care unit.

This randomized controlled trial compared the compliance of a blow-by oxygen method with the standard face mask by children recovering from anaesthesia. The rate at which a face mask was rejected when applied to infants and children in PACU was compared with that of a proposed "hose" method. The efficacy of the "hose" as a method of oxygen supplementation in children at low and high risk for developing postoperative hypoxaemia was also compared with the face mask. Using a Nellcor N-200 pulse oximeter, 66 infants and children (mean age 2.3 yr, range 2 mo-6 yr) were continuously monitored for 30 min upon arrival in the PACU. Patients were randomized to receive oxygen supplementation with either the face mask or the proposed "hose" method. The results showed a greater than 80 per cent rejection of the face mask in contrast to 100 per cent compliance with the "hose" method. The SaO2 measurements following 5, 15 and 30 min of O2 supplementation with the hose were all significantly higher than the SaO2 measurements obtained on room air upon arrival to the PACU. Patients with pre-existing cardiopulmonary disease had a 20 per cent incidence of arterial oxygen desaturation upon arrival to the PACU versus 2.1 per cent of patients with no pre-existing disease. It is concluded that the "hose" is associated with high patient compliance and is effective in the PACU in increasing the SaO2 in children at low or high risk of developing postoperative hypoxaemia.

Initial experience with transvenous implantable cardioverter defibrillator lead systems: operative morbidity and mortality.

Introduction of non-thoracotomy lead systems (Medtronic, Inc.) for the implantable cardioverter defibrillator (ICD) has expanded the indications for use of this mode of therapy. Patients previously considered "too ill" to undergo a thoracotomy as well as patients who are at a high risk for developing sudden death but without previous cardiac arrest, are now considered candidates. The initial experience with the non-thoracotomy lead system at our institution was analyzed for morbidity and mortality. Thirty-four patients underwent attempted intravascular lead implantation, with 30 having initial successful implantation (88.2%). There were 23 males; average ejection fraction (EF) was 38.6%. Three patients developed pulmonary edema and low output immediately after the procedure. Three patients developed electromechanical dissociation during defibrillation threshold testing. A prolonged testing time for the non-thoracotomy lead system was noted when compared to the thoracotomy system (57.39 vs 32.30 min; P < 0.0000). There were more intraoperative morbidities with the non-thoracotomy leads than with the thoracotomy system. There were no perioperative deaths. The potential consequences of prolonged anesthesia time and extensive defibrillation threshold testing should be considered when choosing the route of ICD implant, the type of anesthesia, and the intraoperative testing protocol for each patient.

Long-term stability of defibrillation thresholds with intrapericardial defibrillator patches.

From March 1982 to May 1, 1992, 105 consecutive patients underwent initial implant of cardioverter defibrillators (ICD) at our institution. Twenty-nine patients (23 male and 6 female, average ejection fraction 32.24%) with ICD systems implanted via thoracotomy and either intra- or extrapericardial patches, had one or more revisions including 56 generator changes or staged implant procedures, three patch revisions, one patch lead fracture without revision, and one sensing lead revision. The time between pulse generator revisions averaged 19.5 months. Initial defibrillation threshold mean was 12.8 joules (n = 25); at first revision, 14.46 joules (n = 29), (P = NS); by fifth revision, 15.0 joules (n = 2), (P = NS). One patch was noted to be crinkled at 70 months; one patch had migrated by 39 months, and two patch leads had fractured at the costal margin by 69 and 90 months. One patient with marginal defibrillation thresholds had an additional patch placed at revision to an upgraded ICD unit. Once acceptable defibrillation threshold (DFT) is obtained, the long-term intrapericardial DFT remains stable unless a specific problem occurs. As a small, nonstatistically significant increase in DFT may occur, caution must be exercised in patients with marginal DFTs.

Clinical evaluation of the safety of repetitive intraoperative defibrillation threshold testing.

One goal of the initial implantation procedure for a cardioverter defibrillator is determination of the configuration and patch location with the lowest defibrillation threshold (DFT). To determine the safety of multiple defibrillation tests, an analysis of the intraoperative defibrillation threshold tests (DFTT) in our patients was performed. In 84 patients, the mean number of DFT trials was 5.27; the mean number of joules received was 275.0. The maximum number of shocks in one implant procedure was 50 for a total of 4,895 joules without complications. Four patients received 30 or more DFT shocks without complication. There were two complications related directly to the DFTT: one patient with severe noninflammatory cardiomyopathy developed electromechanical dissociation and was subsequently resuscitated and survived; the second patient with severe triple vessel coronary artery disease suffered an intraoperative myocardial infarction during testing and eventually died 22 days postoperatively. All patients received an ICD unit; six patients had DFTs of greater than 20 joules. Based on our experience, we followed the clinical status (heart rate, blood pressure, ECG changes, fluid status, total anesthesia time) during the DFTT to determine the extent and duration of our testing protocol. Multiple shocks due to repositioning of the leads in a stable patient should not prohibit extensive testing as adverse consequences do not appear to be cumulative.