Upper extremity ischemia is superior to lower extremity ischemia for remote ischemic conditioning of antero-lateral thigh cutaneous blood flow.

Remote ischemic conditioning (RIC) is known to improve microcirculation in various settings, but little is known about the impact of the amount of ischemic tissue mass or the limb itself. Since ischemia and subsequent necrosis of flaps is one of the most dreaded complications in reconstructive surgery, adjuvant methods to improve microcirculation are desirable. We therefore performed a randomized trial to compare the effect of arm versus leg ischemia for RIC of the cutaneous microcirculation of the antero-lateral thigh. Forty healthy volunteers were randomized to undergo 5 min of ischemia of either the upper or lower extremity, followed by 10 min of reperfusion.Ischemia was induced by a surgical tourniquet applied to the proximal limb, which was inflated to 250 mmHg for the upper and 300 mgHg for the lower extremity. This cycle was repeated a total of three times. Cutaneous microcirculation was assessed by combined laser doppler spectrophotometry on the antero-lateral aspect of the thigh to measure cutaneous blood flow (BF), relative hemoglobin content (rHb), and oxygen saturation (StO2). Baseline measurements were performed for 10 min, after which the ischemia/reperfusion cycles were begun. Measurements were performed continuously and were afterwards pooled to obtain a mean value per minute. Both groups showed significant increases in all three measured parameters of cutaneous microcirculation after three cycles of ischemia/reperfusion when compared to baseline (BF: 95.1% (P < 0.001) and 27.9% (P = 0.002); rHb: 9.4% (P < 0.001) and 5.9% (P < 0.001), StO2: 8.4% (P = 0.045) and 9.4% (P < 0.001). When comparing both groups, BF was significantly higher in the arm group (P = 0.019 after 11 min., P = 0.009 after 45 min). In conclusions, both ischemic conditioning of the upper and lower extremity is able to improve cutaneous BF on the ALT donor site. However, RIC of the upper extremity seems to be a superior trigger for improvement of cutaneous BF.

[Postoperative pain management after ambulatory surgery. A survey of anaesthesiologists]. / Postoperative Schmerztherapie nach ambulanten Operationen. Eine Befragung der behandelnden Anästhesisten.

BACKGROUND: Data on practice and quality of postoperative pain treatment by anaesthesiologists after ambulatory surgery are sparse. The current survey enrolled anaesthesiologists in private practice who were responsible for pain therapy after ambulatory surgery. The aim of this investigation was to evaluate the implementation of the German S3 guidelines for acute and postoperative pain therapy in the outpatient setting. PATIENTS AND METHODS: A total of 2,156 anaesthesiologists in private practice received a postal questionnaire which was limited to those anaesthesiologists who were responsible for postoperative pain therapy. The questionnaire included items such as types of surgery, techniques of anaesthesia and analgesic drugs used for pain management during the immediate postoperative phase and for the treatment at home as well as details of pain measurement. RESULTS: Out of 116 responses 108 could be analyzed covering a total of 86,616 patients receiving postoperative pain therapy, 80% of the operations were performed using general anaesthesia and local anaesthesia was additionally used in 9% of the institutions. In the perioperative period 66% of the respondents administered non-steroidal-antiinflammatory drugs (NSAIDs), 62% metamizol (dipyrone), 41% paracetamol (acetaminophen) and 73% opioids. After discharge 81% of the responding anaesthesiologists prescribed NSAIDs, 55% metamizol and 47% opioids for pain relief at home. Only 40% of the respondents measured and documented pain intensity. Nearly all respondents (93%) were satisfied with their pain management after outpatient surgery. CONCLUSIONS: Pain therapy after ambulatory surgery significantly varied with respect to the methods, drugs and measures of quality assurance used by anaesthesiologists in private praxis. This survey demonstrated that the national guidelines of acute pain therapy have only been partially implemented.

Left ventricular assist with an axial flow pump (Hemopump): clinical application.

Eighteen patients suffering from acute left heart failure were selected as candidates for Hemopump support. In 6 patients, peripheral atheromatosis prevented insertion of the device. Of the remaining 12 patients, 9 had postcardiotomy shock, 2 had acute rejection after orthotopic heart transplantation, and 1 had acute myocardial infarction complicated by a large postinfarction ventricular septal defect. During Hemopump support, hemodynamics recovered in all patients. Major complications were related to mechanical pump failure, such as fracture of the drive cable and expulsion of the cannula out of the ventricle, or to hemolysis of variable degree. Seven patients (58%) survived and were discharged from the hospital: the 2 patients bridged to heart transplantation and 5 of the 9 postcardiotomy patients, including 1 who could not be weaned but later underwent successful transplantation. The patient with the postinfarction ventricular septal defect died after removal of the device because of hemolysis. These results indicate that the Hemopump is a relatively noninvasive and efficacious left ventricular system of moderate power.

Combination of extracorporeal membrane oxygenation (ECMO) and pulmonary lavage in a patient with pulmonary alveolar proteinosis.

We describe a rare case of pulmonary alveolar proteinosis in a young woman with dyspnea and progressive hypoxaemia due to the alveolar deposition of insoluble, surfactant-like material. Routine treatment includes whole-lung-lavage (WLL) using double-lumen-tubes for selective lavaging of each lung. We performed three whole-lung-lavages and used veno-venous extracorporeal membrane oxygenation (v-vECMO) to support oxygenation during these procedures.

Hemolysis with the F21 hemopump.

The aim of this study was to determine the influence of mechanical factors on free hemoglobin using an F21 hemopump cannula. These factors (flow, rotary speed, reduction of the cross section area of the silicone tube and foreign material on the screw) were tested in a mock circulation with ox blood. Irrelevant increase in free hemoglobin were induced by foreign bodies either in the inlet or on the screw. The hemopump flow was easily affected and almost suppressed by small amounts of foreign bodies on the screw. Other reasons for elevated concentrations of plasma free hemoglobin may imply a general disorder of the pump, anticoagulation, renal function, red cells or a combination of these factors.

A new pneumatic pump for extracorporeal circulation: TPP (true pulsatile pump). Experimental and first clinical results.

A pulsatile, membrane type pump, TPP, was developed for use in routine cardiac surgery. The artificial ventricle consists of a polycarbonate housing with an inlet and outlet polyurethane tricuspid valve. The membrane is actuated hydraulically. For pre-clinical studies, we designed a study in sheep. After a pump run of 6 hours the animals were allowed to recover and sacrificed after 72 hours. All clinical parameters returned to normal values (p > 0.05 vs. control values). During pump run we found elevated free plasma hemoglobine. However, these values returned to normal until the end of the observation period. Thereafter, the device was used in ten routine cardiac surgery procedures. All patients survived the procedure and were discharged from hospital. The postoperative course of lab parameters (kidney, liver and blood count) was no different to routine cardiac surgical procedures. This pulsatile pump system can thus be safely employed in cardiac surgery.

Pain management in children: assessment and documentation in burn units.

Burns are considered to be among the most painful types of trauma. Especially the pain of children is often unsatisfactorily treated. This study investigates the assessment and documentation of pain by physicians and nurses in children suffering from burns. Pain management was considered sufficient in 80% of ventilated patients and in 60% of non-ventilated patients. The minority of the staff regarded pain management as sufficient during dressing changes after the acute phase and during nursing care. Thirty-eight per cent of the physicians and 58% of the nurses documented the pain. Standardized documentation was used by fewer than 20% of the staff. Pain documentation was not considered relevant for further therapy by 48% of the physicians. More than half of all participants believed that an improvement of the pain therapy performed in their hospital was necessary. Standardized documentation, an algorithm for the application of analgesics, and more training in pain management were desired by many staff members.

Post-traumatic pain. Causes and therapeutic concepts.

Each patient has the right of a dedicated pain therapy according to the state of the art. However an efficient pain therapy is not possible without knowing the cause of pain. In most posttraumatic pain situations peripheral nociceptors are activated and normal afferences are conducted via an intact nociceptive system. In contrast, neuropathic pain pain is caused by lesions of the nervous system itself. Mechanisms of central sensibilization and involvement of the sympathetic nervous system may lead to chronification of such pain conditions. The therapeutic regime of nociceptive and neuropathic pain is demonstrated by algorithms of treatment modalities. Apart from classic non-opioid analgesics, co-analgesics and opioids have an important status in chronic pain management as well. Prescription of these substances has to follow strictly defined standards of pain therapy. Blockades with local anaesthetics as mono-therapy of chronic pain are obsolete. In posttraumatic pain, however, a certain number of adjuvant blockades or infiltrations of triggerpoints may be helpful. The exeptional place of sympathetic blockades are in diagnosis and therapy of sympathetic maintained pain (SMP).

[Postoperative pain after ambulatory surgery]. / Postoperative Schmerztherapie nach ambulanten Operationen.

BACKGROUND: Outpatient surgeons were surveyed about the quality of postoperative pain therapy after outpatient interventions. PATIENTS AND METHODS: Of 2,317 outpatient surgeons who received a questionnaire by mail, 419 responded. The return rate was 18.1%. The questionnaire collected data on the operative procedures and methods of anesthesia from 2004 and the analgesics, which were applied in the immediate postoperative period and at home. Methods and contents of quality control were registered. RESULTS: The respondents indicated that the person responsible for the pain therapy was the surgeon in 74% of the practices, the anesthesiologist in 16%, and both in 10%. The drugs used in the practice were: novaminsulfone (34%), NSAIDs (28%), and opioids (36%). The drugs used for at-home care were: NSAIDs (58%), opioids (43%), novaminsulfone (32%), and mixed analgesics (28%). No analgesics were given by 6%, and 21% prescribed a supplementary antiemetic. Routine pain measurement was performed with pain scales in only 11% of the practices; among the certified practices, 48% performed pain measurement for quality control. Ninety-five percent of the surgeons were satisfied with the pain therapy. CONCLUSION: This survey shows that the guidelines for acute pain therapy (http://www.awmf.de ) are only partially implemented.

[Neurophysiological aspects of pain and its consequences for the anesthetist]. / Neurophysiologische Aspekte von Schmerz und ihre Konsequenzen für den Anästhesisten.

Nociception is a protective system of the body which prevents it from injury and tissue damage. Human beings respond to noxious stimuli by moving away. They learn by pain to avoid these situations in future. Shortly after major injury, there is a limited analgesic period allowing the body to flee the area of danger, later on, emerging pain compels the body to rest and supports recuperation. While acute pain has a certain meaning, chronic pain does not. It induces a comprehensive suffering including loss of initiative, appetite and vigilance. It reduces life-quality, often accompanied by depressive moods. Acute pain causes changes in the central nervous system leading to an increased sensitivity of nociception (hyperalgesia). During healing, the central processing of noxious stimuli is normalised taking minutes to weeks. Sometimes, unknown factors initiate chronification of pain. Changes on a molecular level in peripheral tissue as well as in the central nervous system induce "cellular early genes", a synthesis of c-fos, c-jun and other proteins favouring the chronification of pain. All efforts have to be made to depress or interrupt such a development. One of the first steps to pain prophylaxis in a hospital is an optimal surgical technique: incision, extension, limited tissue damage and minimal invasive surgery should guarantee the smallest impairment of the nociceptive system possible. However, nociceptive input is intense and of long duration and leads to central sensibilisation. Postoperative pain has lost its function as surgery anticipates healing. Pain induces a reduction of ventilation, circulation, digestion and increases the risk of other disorders. There is need of aggressive pain treatment for humanitarian reasons and for reasons of late sequelae like permanent pain and increased reduction of function. This is of pivotal importance in patients with amputations or sympathetic reflex dystrophy (SRD). Antinociception is best provided by regional anaesthesia technique with a combination of local anaesthetics and opioids which results in better outcome. Hence, regional anaesthesia techniques are strongly indicated in those patients. Good antinociception may be even more important than it is assumed today. Anand demonstrated a lower morbidity and mortality in 45 newborns undergoing cardiothoracic surgery, when general anaesthesia was performed with high-dose sufentanil versus halothane supplementary doses of morphine. Anaesthesiologists have to reconsider the quality of general anaesthesia: the antinociception of their regimen.

[Propofol: the ideal long-term sedative?]. / Propofol: Das ideale Langzeitsedativum?

Propofol is commercially available as Disoprivan. It is formulated as an aqueous emulsion with 1% 2,6-diisopropylphenol, 10% soya bean oil, 2,5% glycerol and 1.2% egg phosphatide. Since 1986, propofol has been used as a sedative drug in the ICU and is highly valued for its numerous positive qualities. High effectiveness is combined with excellent control, which is demonstrably still present even after 2 weeks of sedation. This control enables short-term neurological surveillance of the patient and rapid weaning from the respirator once drug administration is stopped. Propofol does not disturb cerebral autoregulation. Depression of spontaneous breathing facilitates the ventilation of intubated patients. As the solution contains lipids, it contributes to parenteral nutrition. All in all, ease of control and rapid response make propofol a highly valued product in ICUs. It is easy to understand why many ICU specialists consider propofol an ideal drug for long-term sedation. The present authors, however, are convinced that certain limitations must be taken into account. First, cardiovascular depression, especially if potentiated by drugs such as beta- and Ca-entry blockers, may lead to hypotensive episodes. Potential problems (drug tolerance, hypertriglyceridaemia) may be revealed in long-term studies. As long as no such studies have been presented, the authors believe that it is too early to consider propofol the ideal drug for long-term sedation.

[A concept for the improvement of postoperative pain management]. / Ein Konzept zur Verbesserung der postoperativen Schmerzbehandlung.

Many articles in the literature document the fact that postoperative pain therapy has not improved for decades despite new insights into pain physiology, the availability of powerful analgesics and the development of new techniques. This project was set up to develop practical, effective, safe, and easy to run acute pain therapy. METHODS. Postoperative pain management had to be optimized according to the facilities available today. Therefore, the legal background is presented first. Second, several medical and organizational principles were chosen to serve as a basis for the new organizational structure: Continuously monitoring the patient's pain during the whole stay in hospital, Introduction of a simple verbal 4-point pain score for determination and documentation of pain allowing the nurses to differentiate pain that should be treated or not, A simple sedation score, Use of "balanced analgesia" and "pre-emptive analgesia", Drug administration according to the needs of the patient, Partial transfer of the responsibility for pain treatment to nurses. Plans and algorithms were expanded to allow nurses and anaesthesiologists to reach the previously determined goals. RESULTS. In a small study including 107 patients, it was demonstrated that the quality of pain treatment improved significantly. Furthermore, patients, nurses and physicians are much more content with the new pain treatment regimen. DISCUSSION. The difficulties in realizing such a concept are described. The importance of thorough teaching is underlined in a nurse-based system. However, it is not yet clear whether this pain treatment has resulted in reduced morbidity, reduced mortality and a shortened hospital stay of the patients.

Use of left-ventricular assist with the Hemopump in cardiac surgery.

From July 1989 to May 1992 16 patients received circulatory support with a Hemopump assist device in the Department of Cardiac Surgery of the Katholieke Universiteit Leuven. The mean age of those patients was 56 +/- 13 years (ranging from 23 to 72 years). The mean time of assisted circulation was 60 +/- 46 h (ranging from 2 to 168 h). Group I consists of 13 patients who received the device after postcardiotomy cardiac failure (survival 38%). Group II includes 1 patient who received the pump prior to repair of a large postinfarction ventricular septal defect (survival 10%). Group III consists of 2 patients for whom the Hemopump was used as a bridge to cardiac retransplantation. Both are still alive (survival 100%). If the 21-F Hemopump is implanted following a critical indication it can be used rather successfully for mechanical circulatory support.

The effects of adding sufentanil to bupivacaine for postoperative patient-controlled epidural analgesia.

We tested the hypothesis that postoperative patient-controlled epidural analgesia was more effective with the combination of sufentanil and bupivacaine (Group 2) than with bupivacaine alone (Group 1). One hundred patients undergoing thoracic, upper abdominal, and aortic surgery were provided with an epidural catheter and randomly allocated to one of the two groups. Postoperatively, patients were monitored in a postanesthetic care unit for at least 1 day before they were transferred to a ward. Both groups had similar demographics and operations. Pain treatment was continued for 4.4 +/- 0.6 and 4.5 +/- 0.7 days for Groups 1 and 2, respectively. Although Group 2 patients needed less volume of the epidural analgesics on Postoperative Days 1 and 2, they reported lower pain intensity at rest and during activity for the first three postoperative days. The groups did not differ from each other regarding the incidence of respiratory depression. There was no late respiratory depression; however, three cases of early respiratory depression were detected and easily treated (Group 1 one event, Group 2 two events). Motor block was only seen in patients with lumbar epidural catheters. There was no difference between groups, and all patients with thoracic catheters could be mobilized beginning on the first postoperative day. We conclude that 1) the addition of sufentanil to a small-dose bupivacaine augments epidural analgesia and 2) thoracic epidural catheters should be used for postoperative analgesia after abdominal or thoracic surgery.

[Oral opioids for long-term treatment of chronic non-cancer pain]. / Orale Opioide zur Langzeittherapie chronischer Nicht-Tumorschmerzen.

The treatment of cancer pain with opioids is well accepted. However, the use of opioids for the treatment of non-cancer pain is still a matter of controversy. The main matters of concern are physical dependence and opioid abuse. Another argument against opioids is the lack of efficacy. Experiences with opioids in non-cancer pain have been published on about 850 patients, the longest therapy lasting almost 14 years. 85% of the patients treated with opioids had beneficial effects. In a number of investigations evaluating the opioid sensibility of pain by PCA and intravenous infusions, 67-80% of the patients with neuropathic pain responded to opioids. The efficacy of opioids in the treatment of non-cancer pain was proven in 3 placebo controlled studies. In 2 studies pain reduction in neuropathic pain was similar to that in nociceptive pain. When opioids are used, the administration has to be performed according to well defined standards. The indication for opioids must be made by a specialist in pain management. The diagnosis must clearly reveal an organic origin of the pain. Before the start of therapy the duration as well as the criteria for discontinuation must be set up. The treatment must be controlled by a specialist team and frequent regular follow up investigations must be performed. These must include proper documentation of the pain level, changes in patients' function and in social activities. The reliable intake of prescribed medication must be assured if necessary by laboratory screening. The treatment of non-cancer pain with opioids may be an alternative for those patients, who didn't gain sufficient reduction of pain by other therapies. Standards for this therapy are an absolute necessity and are to be followed closely.

[Inadvertent potassium chloride infusion in an epidural catheter]. / Versehentliche Infusion von Kaliumchlorid in einen Epiduralkatheter.

In a 65 years old male patient 38 cc of a 7.45% potassium chloride-solution was inadvertently infused within 3 hours into an epidural catheter on the first postoperative day. The epidural potassium chloride administration resulted in a paresis and painful paraesthesia of the patient's legs and a level of sensory blockade to TH 11. Furthermore vegetative symptoms like hypertension and tachycardia were observed. For therapy a single bolus of 40 mg dexamethasone was administered intravenously followed by an epidural infusion of sodium chloride 0.9% 99 cc/h for several hours. About 6 hours after the start of infusion all symptoms had disappeared. It is proposed that the use of colour-coded epidural catheter devices and coloured electrolyte solutions as well as infusion-pumps with a larger reservoir that reduce the frequency of syringe changes would be helpful in avoiding such complications.

[Prevention of "post-sevoflurane delirium" with midazolam]. / Prophylaxe des "Postsevoflurandelirs" mit Midazolam.

In a randomized double-blind placebo-controlled trial in children 2-7 years of age, we investigated the effect of a single prophylactic midazolam bolus (0.1 mg/kg b.w.) prior to the termination of anaesthesia, on the incidence and severity of agitation occurring after sevoflurane administration. Compared to the placebo group, midazolam prophylaxis significantly decreased the incidence of postanaesthetic delirium. However, the incidence of severe agitation requiring treatment was not different between the groups (placebo: n = 6; midazolam: n = 4). The mean severity of agitation was significantly lower in patients with midazolam prophylaxis. When midazolam was administered for the treatment of severe agitation it reduced the severity but did not abolish agitation. All patients were discharged from the recovery room after the 2 h observation period. From our study we conclude that a small prophylactic midazolam bolus is able to reduce the incidence and severity of agitation after sevoflurane anesthesia in some patients but is insufficiently effective in patients with severe agitation. Thus, the prophylactic administration of midazolam extenuates but does not solve the problem of post-sevoflurane agitation.

[Treatment of low back pain--significance, principles and danger]. / Medikamentöse Therapie bei Rückenschmerzen - Bedeutung, Prinzipien und Gefahren.

Today, a wide range of efficient analgesic and non-analgesic drugs for the treatment of back pain are available. However, drugs should never be the only mainstay of a back pain treatment program. Non-steroidal antiinflammatory drugs (NSAID) are widely used in acute back pain. NSAIDs prescribed at regular intervals are effective to reduce simple back pain. The different NSAIDs are effective for the reduction of this pain. They have serious adverse effects, particularly at high doses, in the elderly, and on long-term administration. The new cyclooxygenase II-inhibitors have less gastrointestinal complications. But the long-term experiences are limited up to now. Considerable controversy exists about the use of opioid analgesics in chronic noncancer pain. Many physicians are concerned about the effectiveness and adverse effects of opioids. Other clinicians argue that there is a role for opioid therapy in chronic noncancer pain, e. g. especially in chronic low back pain. There is a low incidence of organ toxicity in patients who respond to opioids. The incidence of abuse and addiction is likewise relatively low. The potential for increased function and improved quality of life seems to outweigh the risks. However, there is a lack of randomised controlled trials (RCT) on opioid therapy in a multimodal pain treatment approach. Clinical experience and some studies suggest administration of sustained release opioids because of better comfort for the patient and less risks for addiction. The opioids should be selected due to the specific side effects of the different drugs. For patients with pre-existing constipation transdermal fentanyl should be preferred. Antidepressant medications have been used for the treatment of chronic back pain, though there is only little scientific evidence for their effectiveness. There is no evidence for the use of antidepressants in acute low back pain. Trials of muscle relaxants for patients with acute back pain have used a wide range of agents, e. g. benzodiazepines. They mostly reduce acute back pain, but they have significant adverse effects including drowsiness and psychological and physical dependence even after relatively short treatment. Benzodiazepines are not indicated in the treatment of chronic back pain. Drugs are sometimes necessary for the patients to begin and persevere a multimodal treatment program. Drug therapy should be terminated as soon as other treatment strategies succeed. Unfortunately, no studies exist evaluating the place of analgesics within a multimodal treatment program.

[Delayed negative pressure pulmonary edema]. / Verzögert auftretendes, postobstruktives Lungenödem.

A young athletic male adult (smoker) developed a pulmonary edema 30 min after the end of anaesthesia. Extubation was complicated by a laryngospasm. After artificial ventilation for 12 h the patient recovered completely.A negative pressure pulmonary edema (NPPE) develops after deep inspiratory efforts with an occluded airway. Such a maneuver leads to negative intrapleural pressures of -50 to -100 mmHg. This pressure gradient causes damage to the pulmonary capillaries, a transcapillary volume shift into the interstitium,and hemodynamic changes that increase the intrapulmonary blood volume. As a NPPE may occur with a delay of up to 1 h it is crucial to provide adequate monitoring for patients at risk. Symptomatic therapy usually leads to complete recovery within several hours.