Gerhard Fritsch

Dexmedetomidine added to ropivacaine extends the duration of interscalene brachial plexus blocks for elective shoulder surgery when compared with ropivacaine alone: A single-center, prospective, triple-blind, randomized controlled trial

Background and Objectives Research suggests that the addition of dexmedetomidine to local anesthetics can prolong peripheral nerve blocks; however, clinical safety data are limited, and interscalene blocks have not been studied. The present study was designed to test the hypothesis that dexmedetomidine added to ropivacaine would safely enhance the duration of analgesia without adverse effects when compared with ropivacaine alone. Methods We conducted a single-center, prospective, randomized, triple-blind, controlled trial of 62 patients undergoing elective shoulder surgery under general anesthesia with an interscalene block. Patients underwent ultrasound-guided interscalene blocks using either 12 mL of 0.5% ropivacaine or 0.5% ropivacaine plus 150-µg dexmedetomidine. The primary outcomes were self-reported duration of the nerve block and safety assessment (adverse effects and neurological sequelae). Data were analyzed in a blinded fashion. Results The median duration of the nerve block was 18 hours (95% confidence interval, 18–20) in the dexmedetomidine group and 14 hours (95% confidence interval, 14–16) in the ropivacaine group (P = 0.0001). Dexmedetomidine also lowered pain scores for the first 14 hours postoperatively and significantly hastened the time to sensory (P = 0.04) and motor (P = 0.002) block onset. Dexmedetomidine lowered heart rate but blood pressures were stable. Plasma levels of ropivacaine were not different between groups, and plasma dexmedetomidine levels were relatively low. There were no adverse events or neurological sequelae. Conclusions Dexmedetomidine added to ropivacaine for interscalene blocks increased the duration of the nerve block and improved postoperative pain. These additional efficacy and safety data should encourage further study of peripheral perineural dexmedetomidine in humans.

Abnormal pre-operative tests, pathologic findings of medical history, and their predictive value for perioperative complications.

Laboratory tests, electrocardiogram (ECG) and chest X‐rays still serve as part of the routine assessment before elective surgery in many institutions, even though there is little evidence of their predictive value relating to perioperative complications. This study investigates the correlation of abnormal findings in pre‐operative tests and pathologic findings in the medical history with perioperative complications.

Effectiveness of non-cardiac preoperative testing in non-cardiac elective surgery: a systematic review

Elective surgery is usually preceded by preoperative diagnostics to minimize risk. The results are assumed to elicit preventive measures or even cancellation of surgery. Moreover, physicians perform preoperative tests as a baseline to detect subsequent changes. This systematic review aims to explore whether preoperative testing leads to changes in management or reduces perioperative mortality or morbidity in unselected patients undergoing elective, non-cardiac surgery. We systematically searched all relevant databases from January 2001 to February 2011 for studies investigating the relationship between preoperative diagnostics and perioperative outcome. Our methodology was based on the manual of the Ludwig Boltzmann Institute for Health Technology Assessment, the Scottish Intercollegiate Guidelines Network (SIGN) handbook, and the PRISMA statement for reporting systematic reviews. One hundred and one of the 25 281 publications retrieved met our inclusion criteria. Three test grid studies used a randomized controlled design and 98 studies used an observational design. The test grid studies show that in cataract surgery and ambulatory surgery, there are no significant differences between patients with indicated preoperative testing and no testing regarding perioperative outcome. The observational studies do not provide valid evidence that preoperative testing is beneficial in healthy adults undergoing non-cardiac surgery. There is no evidence derived from high-quality studies that supports routine preoperative testing in healthy adults undergoing non-cardiac surgery. Testing according to pathological findings in a patients medical history or physical examination seems justified, although the evidence is scarce. High-quality studies, especially large randomized controlled trials, are needed to explore the effectiveness of indicated preoperative testing.

Non-adherence to guidelines for preoperative testing in a secondary care hospital in Austria: the economic impact of unnecessary and double testing.

Context Preoperative evaluation is aimed at prevention of complications and risk stratification. Routine testing should be abandoned in favour of selective ordering according to contemporary guidelines. This study was conducted to calculate the possible economic impact of a Web-based preoperative diagnostic guideline prior to its implementation in the state of Salzburg, Austria. Design Prospective observational cohort study. Setting The study was carried out in a secondary care hospital in Salzburg (Schwarzach). Participants and main outcome measures Data from 1363 consecutive patients scheduled for elective surgery from 1 September to 30 November 2007 were collected: demographic data, medical history, surgical procedure, preoperative tests and findings. The data were entered into the preoperative diagnostic guideline software and the guideline-adherent recommendations were compared with the investigations performed, with special attention to duplicate examinations. Results A total of 5879 tests were documented and analysed. In 65.6% of patients, guideline-adherent evaluation would have indicated only basic requirements, but 3380 additional tests were carried out. In all, 81.7% of tests were identified as nonadherent based on the preoperative diagnostic guideline software and 226 duplicate tests were performed. Possible savings per 1000 patients would be &OV0556;26 287 if preoperative diagnostic guideline recommendations were followed exactly and &OV0556;1076 if duplicated tests were avoided. According to a generalised linear model (Gamma model), an increase of 1 year of age leads to an increase of costs by a factor of 1.020. Conclusion These data indicate a considerable potential for improvement in process quality and cost reduction by using structured preoperative assessment with computer-assisted implementation of a guideline.

The impact of preoperative testing for blood glucose concentration and haemoglobin A1c on mortality, changes in management and complications in noncardiac elective surgery: a systematic review.

BACKGROUND The risks associated with surgery are elevated in patients with diabetes mellitus. For this reason, preoperative diagnostics frequently include the measurement of blood glucose and haemoglobin A1c (HbA1c), but it is unclear whether these tests contribute to improved perioperative or postoperative outcomes. OBJECTIVES This systematic review aimed to evaluate the evidence that preoperative testing for blood glucose and HbA1c might influence the following outcome parameters: changes in clinical management; mortality; and the incidence of perioperative and postoperative complications in patients undergoing elective, noncardiac surgery. DESIGN We performed a systematic search of the literature from January 2001 to March 2013, thus updating a review carried out by the National Institute for Health and Clinical Excellence (NICE) up to the year 2001. ELIGIBILITY CRITERIA Controlled studies including cohort and case–control studies with a population of at least 60 patients were eligible. RESULTS The search retrieved 1346 records (including hand-search). Twenty-two studies met all inclusion criteria and were included in the review. Fifteen cohort and two case–control studies evaluated the effectiveness of preoperative blood glucose testing and nine studies the effectiveness of testing HbA1c. Four of the included studies evaluated both tests. There were no data derived from high-quality studies supporting routine preoperative testing for blood glucose or HbA1c in otherwise healthy adult patients undergoing elective noncardiac surgery. Only in vascular and orthopaedic surgery may screening identify patients at an increased risk. CONCLUSION Preoperative blood glucose testing and testing for HbA1c is not required in nondiabetic patients unless there are clinical sings arousing suspicion. Patients scheduled for vascular and orthopaedic surgery carry an elevated risk justifying preoperative testing for blood glucose or HbA1c as a screening tool.

Preoperative Laboratory Testing

Routine preoperative testing is not cost-effective, because it is unlikely to identify significant abnormalities. Abnormal findings from routine testing are more likely to be false positive, are costly to pursue, introduce a new risk, increase the patients anxiety, and are inconvenient to the patient. Abnormal findings rarely alter the surgical or anesthetic plan, and there is usually no association between perioperative complications and abnormal laboratory results. Incidental findings and false positive results may lead to increased hospital visits and admissions. Preoperative testing needs to be done based on a targeted history and physical examination and the type of surgery.

Utility of Intraoperative Lung Ultrasonography

A patient with an endobronchial tumor and critical airway obstruction developed hypoxia and hypercarbia and, subsequently, cardiac arrest during a palliative laser core-out excision. The differential diagnosis included tension pneumothorax, as well as airway obstruction due to swelling of residual tumor or to blood clots. In this case, empiric needle decompression could have had deleterious consequences. Immediate bedside lung ultrasonography provided real-time information leading to the stabilization of the patient. This case provides compelling motivation for anesthesiologists to acquire this easily learned skill.

Bilateral Loss of Neural Function After Interscalene Plexus Blockade May Be Caused by Epidural Spread of Local Anesthetics: A Cadaveric Study

Background and Objectives Interscalene brachial plexus blockade is widely used in surgical procedures of the upper limb. Recently, we experienced the complication of a contralateral blockade after ultrasound-guided interscalene block. The clinical appearance was a blockade of both the ipsilateral and the contralateral cervical segments 6 to 8. We hypothesized that epidural spread of local anesthetics could be cause for this phenomenon. Methods We conducted a cadaveric study using ultrasound for needle guidance of interscalene blocks in 5 cadavers by a single investigator using contrast agent. Injections were made either ventral (extrafascial) or dorsal (subfascial) to the prevertebral lamina of the deep cervical fascia. Computed tomography was obtained following each injection with contrast agent immediately after incremental injections of progressively higher volumes. Subsequently, contrast spread to anatomic landmarks was investigated by a radiologist. Results After ultrasound-controlled injection of contrast agent beneath the prevertebral layer of the deep cervical fascia, 4 of the 5 investigated specimens showed contrast enhancement in the epidural space in the consecutive computed tomography scans. After extrafascial injection, none of the investigated specimens showed contrast enhancement in the epidural space. Conclusions Contralateral blockade after ultrasound-guided interscalene injection of local anesthetics is very likely to be the effect of epidural spread. Future in vivo studies are needed to understand the implications of needle location and volume on epidural spread in interscalene blockade.

Minimizing cardiac risk in perioperative practice – interdisciplinary pharmacological approaches

ZusammenfassungHINTERGUND: Die demographische Bevölkerungsentwicklung hat zur Folge, dass chirurgische Eingriffe bei einer größeren Anzahl von Patienten mit komplexen Begleiterkrankungen durchgeführt werden. Die perioperative Morbidität wird auf Grund dieses geänderten Risikospektrums hauptsächlich durch kardiale und respiratorische Komplikationen bestimmt. METHODEN: In dieser Übersichtsarbeit werden pharmakologische Ansätze der perioperativen kardiovaskulären Risikoprotektion (einschließlich der Auswirkungen rückenmarksnaher anästhesiologischer Regionalverfahren und der Erhaltung der Normothermie) auf das kardiale Outcome chirurgischer Patienten behandelt. Die einzelnen Kapitel sind folgendermaßen strukturiert: Pathophysiologie – Bekannte Studien – Neue Evidenz – Leitlinien/Empfehlungen. ERGEBNISSE: Es werden zunehmend innovative Konzepte wie die fast-track Chirurgie und neue pharmakologische Behandlungsstrategien eingesetzt, um diesen Herausforderungen zu begegnen. Hierbei handelt es sich um die medikamentöse Kardioprotektion, neue Strategien der Antikoagulation und Antiaggregation sowie um Behandlungspfade für die postoperative Schmerztherapie. SCHLUSSFOLGERUNG: Diese Konzepte beinhalten einen interdisziplinären Ansatz mit der strikten Kollaboration zwischen operativen Disziplinen und nicht-chirurgischen Disziplinen wie Innere Medizin, Kardiologie und Pharmakologie. Eine bereits bestehende Therapie mit Beta-Blockern oder anderen wahrscheinlich kardioprotektiven Medikamenten wie α2-Agonisten und Statinen sollte perioperativ weitergeführt werden. Die Beurteilung des Gesamtrisikos vor größeren Operationen sollte durch das mit dem Eingriff verbundene Risiko und den klinischen kardiologischen Zustand des Patienten erfolgen. Ansonsten könnten Nebenwirkungen einer potentiell effektiven Therapie deren Nutzen überwiegen. So sollte eine perioperative Therapie mit Beta-Blockern, wie kürzlich gezeigt, einem definierten Kollektiv von Hochrisiko-Patienten vorbehalten bleiben.SummaryBACKGROUND: In an aging population, major surgery is often performed in patients with complex co-morbidities. These patients present new risk constellations so that cardiac and respiratory complications mainly contribute to perioperative morbidity. METHODS: We composed a narrative review on pharmacological approaches to cardiovascular protection in the perioperative period including effects of central neuraxial blocks and hypothermia on cardiovascular outcome. The single chapters are structured as follows: pathophysiology-early studies-recent evidence-recommendations. RESULTS: In coping with this challenge, innovative concepts like fast track surgery and pharmacological treatment are being utilized with increasing frequency including perioperative cardioprotection, novel strategies of anticoagulation or antiplatelet therapy, and protocols for postoperative pain therapy. CONCLUSION: All the concepts described require an interdisciplinary approach in collaboration between operative physicians and physicians working in non-surgical disciplines like internal medicine, cardiology, and clinical pharmacology. The perioperative continuation of a pre-existing therapy with beta-blockers and other potentially cardioprotective agents like α2-agonists and statines is recommended. In the management of patients presenting for major surgery stratification of the perioperative risk is essential which considers both, invasiveness of the surgical procedure and conditions of the patient. Otherwise, side-effects might outweigh benefits of a potentially effective therapy as recently shown for the perioperative administration of beta-blockers that should be restricted to high-risk patients.

ProPath - A guideline based software for the implementation into the medical environment

Over the last decades, the amount of medical information has been growing rapidly. Online platforms such as patients and doctors blogs and forums and medical databases are widely and easily accessible to medical professionals as well as to the public. However, researching, filtering and evaluating the quality of this often overwhelming amount of data remains a challenge. Moreover, existing guidelines in the medical context are extensive and hardly applicable in the clinical context since reading and translation into clinical practice is time consuming [1][2]. Due to growing critical awareness among patients towards their medical treatment, there is an increased demand from internists, general practitioners, and other specialists, to explain medical conditions, treatment options and procedures in a more comprehensive fashion. In addition this discussion should be supported by the current state of clinical research. Expert systems could provide valuable support to fulfill these needs. Initial prototypes of expert systems in the inpatient arena were already implemented in the 1960s in the context of clinical trials [3]. The main goal of these systems was to improve medical care by assisting in the medical decision process. However, most of these systems did not remain in clinical practice for a prolonged period of time. In most cases, the user interface of the software was too complex for daily use. Appropriate application and a detailed insight into these systems requires a lot of handbook knowledge. Therefore the initial hurdles for the integration of software into specific clinical application, faced by the potential users were too cumbersome. The main purpose of the project ProPath was to eliminate these issues and at the same time provide optimal clinical practice for the health care system in a variety of medical topics. Both in the outpatient and inpatient scenario, there is an increasing demand to support communication and to improve the distribution of published knowledge and the application of practical experiences within the medical field. The main challenge to achieve that objective is to design an intuitive, user friendly software product that can be integrated into the current standard network environments. An example of successful implementation of a medical information system into clinical practice is the PROP system [4]. It is a medical decision support system, which has been designed, developed and implemented in Austria in the course of Reformpoolprojekt, in order to optimize the preoperative process. Since 2008, it is applied by general practicioners, pediatricians, clinicians and internists, in the state of Salzburg and was externally evaluated by the Paracelsus Medical University (PMU) in Salzburg. This paper provides an overview on how acquired knowledge can be utilized to reduce the complexity of designing and implementing clinical pathways (ProPath), supported by medical information or expert systems. Finally, statistical results evaluating PROP user-behavior are described.