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Epidural fentanyl and caesarean section: when should fentanyl be given?

Epidural fentanyl is often added to epidural local anaesthetic agents to improve the quality of anaesthesia obtained during Caesarean section. Fentanyl may be given either before or after delivery of the infant. When given before delivery, fentanyl has not been reported to cause neonatal depression, although this remains a concern. A prospective, randomized, double-blind study was undertaken to determine if fentanyl was more effective if given before or after delivery of the baby in 64 women undergoing Caesarean section under lidocaine epidural anaesthesia. Maternal outcome was determined by time to achieve T4 neural blockade, the dose of lidocaine necessary to achieve this block and intraoperative scores for pain, nausea, vomiting, shivering, and sedation. Neonates were assessed by umbilical arterial blood pH and Apgar scores. No differences were detected in either group with respect to maternal or neonatal outcome. We recommend using only epidural local anaesthetic agents before delivery, and giving epidural fentanyl following delivery of the infant.

Adult↗

Rewarming following hypothermic cardiopulmonary bypass in the malignant hyperthermia-susceptible patient: implications for diagnosis and perioperative management.

A 55-year-old, malignant hyperthermia-susceptible patient underwent myocardial revascularization without incident. Six hours postoperatively, he developed what was initially diagnosed as an MH crisis, for which he received intravenous dantrolene. The resultant muscle weakness prolonged the duration of postoperative mechanical ventilation and likely contributed to the development of a postoperative pneumonia. Plasma dantrolene levels were measured for the first 48 hours postoperatively and correlated with clinical findings. On reviewing the patient's perioperative course, it was felt that the hypermetabolic state was not due to MH. The patient's pattern of rewarming following hypothermic cardiopulmonary bypass was similar to non-MH-susceptible patients. Because of the difficulty in diagnosing a MH crisis after hypothermic bypass, it is recommended that patients receive prophylactic dantrolene preoperatively and after bypass. Nondepolarizing muscle relaxants should be given postoperatively to prevent shivering and respiratory acidosis while patients rewarm.

Cardiopulmonary Bypass↗

Caesarean section for twins in a patient with myotonic dystrophy.

The management of a patient with myotonic dystrophy undergoing Caesarean section for delivery of twins in breech position is reported. Anaesthetic management must reflect the multi-system nature of the disease in addition to the implications of pregnancy. Known triggers of myotonic crisis (succinylcholine, shivering) must be avoided. Attention to respiratory reserve is necessary in view of the restrictive defect this disease can impose. Cardiomyopathy and conduction system disturbances may be features. Upper gastrointestinal incoordination can superimpose the added risk of aspiration on the pregnant myotonic. Ineffective uterine contraction can cause vigorous post partum haemorrhage. Endocrine disturbances, especially diabetes mellitis, may be present. There may be increased sensitivity to sedative and narcotic agents. The newborn myotonic will need the expertise of neonatal care.

Adult↗

Hypertension after epidural meperidine.

The use of epidural opiates, unlike the use of epidural local anaesthetics, is considered to have little, if any, effect on the cardiovascular system. A 76-year-old man with a flail chest injury was given a lumber epidural injection of meperidine. During the injection he suddenly complained of feeling cold, shivered vigorously and became tachypneic. His arterial blood pressure rose from 170/70 to 300/100; his pulse rate rose to 150/min. The patient was severely hypertensive for 40 minutes until treated with intravenous phentolamine. There is increasing evidence in the literature implicating the involvement of endogenous opiates in the central control mechanisms of blood pressure control.

Accidents, Traffic↗

Anaesthetic management of labour and delivery in the parturient with mitochondrial myopathy.

PURPOSE: We describe the anaesthetic management for Caesarean section in a parturient with a defect in complex III of the respiratory chain who had increased lactate concentrations at rest and with exercise. CLINICAL FEATURES: We administered effective epidural anaesthesia with lidocaine for Caesarean delivery. The serum lactate concentration was less than the preoperative value both during and after surgery. Shivering during the perioperative period was avoided by administering warm i.v. fluids, warm local anaesthetic solution and epidural meperidine. Pain relief after surgery was provided with i.v. PCA morphine augmented by local infiltration with bupivacaine to fascia and skin edges and epidural injection with meperidine. CONCLUSION: Mitochondrial myopathies are an uncommon group of disorders in which mitochondrial dysfunction leads to clinical disease of muscle and sometimes of other organs with high energy requirements. The management of labour and delivery in women with mitochondrial myopathies should be individualized according to severity of disease and formulated by consultation between attending physicians and the anaesthetist. Epidural analgesia reduces stress and work associated with labour and reduces oxygen demand during labour. However, parturients with defects of the respiratory chain with documented increased lactate concentrations at rest and with exercise are best managed with elective Caesarean delivery with regional anaesthesia to prevent life-threatening lactic acidosis during labour. The association between malignant hyperthermia and these disorders has not been proved, but it appears prudent to consider these women as MH susceptible until definitive data regarding this possible relationship are available.

Adult↗

Heat conservation vs convective warming in adults undergoing elective surgery.

PURPOSE: To determine the relative efficacy of heat conservation and convective warming in maintaining perioperative normothermia, (central temperature > or = 36 degrees C). METHODS: Thirty-seven patients undergoing elective gynaecological, orthopaedic, or general surgery scheduled to last two hours were prospectively studied. Patients were randomized to one of two groups. Group 1 patients received heat conservation with reflective blankets (Thermadrape, Vital Signs, Inc., Totowa, NJ) applied preoperatively and warmed i.v. fluids (Hotline SIMS Level I Technologies, Inc, Rockland, MA), Group 2 patients received convective warming (BairHugger, Augustine Medical Inc., Eden Prairie, MN) after induction of anaesthesia and i.v. fluids at room temperature. All patients received general anaesthesia with isoflurane. Tympanic membrane and forearm-fingertip skin temperature gradients were measured perioperatively at 15 min intervals. RESULTS: Central temperature decreased after induction to a minimum level of 35.9 +/- 0.1 degrees C in group 1 and 36.0 +/- 0.1 degrees C in group 2 and then increased towards pre-induction values in group 2, and were higher (P < 0.05) than in group 1: 95% group 2 patients had central temperature > or = 36.0 degrees C at the end of surgery (vs 69% of group 1, P < 0.05). During the first 30 min in PACU, central temperatures were higher in group 1 than in group 2 (36.8 +/- 0.1 degrees C vs 36.2 +/- 0.2 degrees C, P < 0.05). After 60 min, central temperatures were similar (36.8 degrees C). The incidence of shivering and degree of peripheral cutaneous vasoconstriction were also similar. CONCLUSION: Patients receiving convective warming were more likely to leave the operating room normothermic, and had higher central temperatures during the first 30 min in the recovery room. The intergroup temperature differences were small, and by 60 min, had disappeared.

Adult↗

[Total intravenous anesthesia with propofol and remifentanil. Results of a multicenter study of 6,161 patients].

INTRODUCTION: The aim of this study was to investigate efficacy and tolerability of propofol, remifentanil and cisatracurium or mivacurium in routine anesthetic practice. PATIENTS AND METHODS: A total of 6,161 patients scheduled for abdominal or orthopedic surgery were included in this open multicenter phase IV study. Perioperative hemodynamics as well as induction, recovery and discharge times, anesthetics, frequency of PONV and side-effects were studied. RESULTS: Quality of induction and maintenance of anesthesia were evaluated by anesthesiologists to be good or very good in 88%. 86% of the patients assessed anesthesia as good or very good. Adverse events were reported for 28 patients (0.45%), with hypotension and bradycardia being most frequent. Recovery was evaluated by anesthesiologists to be good or very good in 88%, surgeons and nursing staff assessed the TIVA as good or very good in 90%. Most frequent postoperative complaints were pain (16.7%), nausea (6.1%), shivering (3.1%) and vomiting (0.7%). CONCLUSIONS: The study showed that total intravenous anesthesia using propofol, remifentanil and cisatracurium or mivacurium is safe, tolerable and effective and has a high degree of acceptance.

Abdomen↗

[Cholinesterase inhibitors. Importance in anaesthesia, intensive care medicine, emergency medicine and pain therapy].

Many drugs currently used in anaesthesia practice modify cholinergic transmission, therefore, acetylcholinesterase inhibitors are a part of anaesthetic pharmacology. Besides its well established use in the antagonism of neuromuscular blockades and the therapy of central anticholinergic syndrome (CAS), results of controlled studies and case reports suggest other favourable indications such as the prevention and therapy of postanaesthetic shivering and the treatment of various types of intoxication and delirium. Cholinesterase inhibitors may also have analgesic properties. This review summarises the pharmacological and physiological background and describes favourable indications of this class of drugs.

Acetylcholine↗

[Total intravenous anesthesia with methohexital-alfentanil or propofol-alfentanil in hypogastric laparotomy. Clinical aspects and the effects of stress reaction].

Total intravenous anaesthesia (TIVA) using a combination of a hypnotic and an analgesic agent is gaining increasing popularity as an alternative to balanced anaesthesia with volatile anaesthetics for abdominal surgery. Among the required characteristics of the drugs used in this technique are a good correlation between dose, plasma concentrations, and effect as well as rapid elimination from the circulation, allowing close control of anaesthetic depth. Two hypnotic drugs with similar pharmacokinetic and pharmacodynamic profiles are propofol and methohexitone, both of which can be employed as a component of a TIVA technique. Two TIVA combinations utilising either of these drugs with alfentanil were tested against isoflurane-nitrous oxide in a balanced regimen. METHODS. Twenty-seven healthy women undergoing hysterectomy for non-malignant diseases participated in the study after having given written consent. They were randomly allocated to receive either isoflurane (Iso), methohexital-alfentanil (M-A), or propofol-alfentanil (P-A). Blood samples for determination of cortisol, prolactin, catecholamines, glucose, lactate, non-esterified fatty acids, and pharmacon concentrations were drawn repeatedly from before induction until 360 min after surgery. Anaesthesia was induced in group Iso with fentanyl 0.1 mg and M 1.5 mg.kg-1 and maintained with Iso-N2O. In the TIVA groups M or P was given in a two-step infusion to load peripheral compartments and then maintain plasma concentrations within the hypnotic range. A was given as a continuous infusion in an identical dose (0.1 mg.kg-1 initial, 0.125 mg.kg-1.h-1 maintenance) in both groups. If signs of insufficient depth of anaesthesia occurred (heart rate or systolic blood pressure > 25% above baseline), then first A (0.5-1 mg), and if that was ineffective, then 50 mg hypnotic was administered. The A infusion was stopped 30 min before the end of surgery, and Iso or the hypnotic was stopped at skin closure. Recovery time was the time until the patients were able to give their birth date after stopping the Iso or hypnotic. RESULTS. The three groups were comparable with regard to age, weight, and duration of surgery. The total doses of M and P were 1,357 +/- 125 mg (mean +/- SEM) and 1,315 +/- 121 mg, respectively, and the total A doses were 20.7 +/- 2.5 mg (M-A) and 23.4 +/- 3.5 (P-A). The peak plasma concentrations were P 10.6 +/- 1.5 micrograms.ml-1 and M 12.4 +/- 2.6 micrograms.ml-1. At the end of surgery the P concentrations were in the projected range while those of M were somewhat lower than expected (P 3.7 +/- 0.4 microgram.ml-1; M 3.5 +/- 0.6 microgram.ml-1). Three patients each in the P-A and M-A groups required supplementary A injections. Five patients in the P-A group required additional bolus injections of the hypnotic as compared to 2 in the M-A group. The median recovery times were Iso 15 min, M-A 50 min, and P-A 25 min (P < 0.05). The incidence of shivering was Iso 3/9, M-A 5/9, and P-A 0/9 (P < 0.05); vomiting occurred with equal frequency in all groups (Iso 33%, M-A 33%, P-A 22%). The patients were somewhat more restless in group M-A. Systolic blood pressure dropped in a similar manner in all groups after induction of anaesthesia (Iso -31%, M-A -37%, P-A -36%) but recovered during surgery. The intraoperative response of cortisol (Iso + 216%, M-A +92%, P-A +43%) and catecholamines (noradrenaline Iso +56%, M-A +30%, P-A -21%) was lower in the TIVA groups, whereas prolactin increased after induction in all groups. Plasma concentrations of glucose, lactate, and fatty acids were lower in the TIVA groups than in the Iso group intraoperatively, but increased to comparable postoperative levels. CONCLUSIONS. Both TIVA regimens are acceptable alternatives to balanced anaesthesia with Iso N2O. (ABSTRACT TRUNCATED)

Adult↗

[Inverse fick's principle in comparison to measurements of oxygen consumption in respiratory gases. Does intrapulmonary oxygen uptake account for differences shown by different system methods?].

Automated measurements of respiratory gas exchange recently became available for the determination of oxygen uptake (VO2) in critically ill patients. Whereas these metabolic gas monitoring systems (MBM) are assumed to measure total body VO2, the reversed Fick method in principle excludes intrapulmonary VO2. Previous clinical reports comparing VO2 measured by the reversed Fick principle (VO2Fick) with VO2 measured by MBM (VO2MBM) found that VO2MBM was significantly greater than VO2Fick. It was suggested that these differences between methods represent VO2 of pulmonary and bronchial tissue, as intrapulmonary VO2 had been estimated to account for 15% of total body VO2 in dogs with experimental pneumonia. The objective of this study was to compare VO2Fick with VO2MBM in patients with and without pneumonia and to assess the reproducibility of both methods in critically ill patients. METHOD. With institutional approval nine critically ill patients with acute pneumonia were studied under controlled mechanical ventilation. The diagnosis of pneumonia was based on respective changes of chest X-rays, body temperature > 38 degrees C, and WBC counts > 12,000/mm3. Inspiratory oxygen fractions (FIO2) ranged from 0.3 to 0.6; all patients routinely received opioids and hypnotics. Complete muscle relaxation was achieved during the periods of measurement to avoid sudden changes in VO2 due to shivering or involuntary movements. Arterial and pulmonary-arterial blood samples were drawn simultaneously after aspiration of the sevenfold catheter dead space. Measurements of haemoglobin concentration (Hb), fractional oxygen saturation (SO2), and O2 partial pressure (PO2) were performed by use of a calibrated haemoximeter and blood gas analyser, respectively; 2 x 5 thermodilution measurements of cardiac output (CO) were spread randomly over the respiratory cycle for each determination of VO2Fick. To minimise systematic errors of CO measurements, the CO computer was calibrated in an extracorporeal flow model using an electromagnetic flowmeter. Calculations of VO2Fick were based on an oxygen binding capacity of 1.39 ml/g Hb. Simultaneous measurements of VO2MBM were obtained by use of a Datex Deltatrac MBM that had been validated in vitro with a gas dilution model of respiratory gas exchange. Calibration of the MBM was performed prior to each measurement. Gas supply of the respirator was provided by an external high-precision mixing device to reduce errors in VO2 measurements that may arise from short-term oscillations in FIO2. All patients with pneumonia were studied on three consecutive days; thus, measurements from 27 days could be analysed. On each day two sets of measurements were performed at an interval of 60 min to assess the reproducibility of differences between methods. During each set of measurements duplicate blood samples were drawn twice, before and after thermodilution measurements of CO, to evaluate the short-term repeatability of VO2Fick. The beginning and the end of each set of measurements were marked in the computer record of the MBM to assess the respective repeatability of VO2MBM. Fifty control measurements were performed in ten patients undergoing major neurosurgical procedures. None of these patients exhibited signs of pulmonary infection. Except for the number of repeated measures, all VO2 measurements were obtained in the same way as in the study group. Descriptive statistical analysis was performed according to Bland and Altman; comparisons between methods were done by multivariate analysis of variance for repeated measures. RESULTS. Neither in the study group nor in the control group could a significant difference between methods be demonstrated. In patients with pneumonia the mean difference between methods (VO2Fick-VO2MBM) was 15.2 ml/min (4.2%); the double standard deviation of differences (2 SD) was 59.2 ml/min (19.2%).

Blood Gas Analysis↗

[Repeated addition of fentanyl to bupivacaine peridural analgesia in labor. Clinical action and fentanyl plasma level].

A combination of epidural opioids with local anaesthetics has been used to improve pain relief during labor and to reduce side effects, such as muscle weakness, usually seen when local anaesthetics are used alone. The addition of epidural fentanyl (F) produces highly effective analgesia, the only side effect being mild itching. Initial trials investigated the improvement in analgesia after a single administration of F during first- but not during second-stage labor. Even though pain perception during second-stage labor under epidural analgesia with local anaesthetics can be severe, the addition of opioids was avoided for fear of neonatal or maternal depression. A recent report found maternal and umbilical plasma concentrations following injection of 100 micrograms F to be safe and the investigators speculated that repeated addition of epidural/F to injection of local anaesthetic may prove beneficial for the parturient without exposing the mother or fetus to risk. We therefore studied maternal analgesia, maternal and umbilical plasma levels and associated side effects following repeated addition of 100 micrograms F to bupivacaine epidural analgesia during labor. METHODS. Following institutional and governmental approval 53 parturients were randomly assigned to receive either 8 ml bupivacaine 0.25% + 0.1 mg fentanyl (B + F group; n = 28) or 8 ml bupivacaine 0.25% + 2 ml saline (BUP group; n = 25) in an epidural catheter at L2/3. The same dose was reinjected upon the patients' request regardless of the degree of cervical dilatation. Blood pressure, heart rate, respiratory rate and the incidence of side effects were recorded before and following each epidural injection. Pain relief was determined at each injection and following cord clamping using the visual analogue pain scale (VAS; 0-100 mm). Maternal venous blood samples were collected to measure plasma F concentrations before and 20 and 40 min after each injection and at birth when umbilical venous and arterial blood was obtained. After centrifugation the samples were maintained at -20 degrees C and then analyzed by radioimmunoassay. At delivery, Apgar scores and umbilical venous and arterial blood gas values were determined. RESULTS. Both groups were comparable for age, weight, height, gestational age and parity. A total of 48 epidural injections were evaluated in the B + F group, 43 in the BUP group. No statistically significant group difference was found between the frequency of injections per delivery (B + F: 2.2; BUP: 1.8); regarding the time between the initial and the first top-up dose (B + F: 144 min; BUP: 140 min) or regarding the interval between the last injection and birth (B + F: 94 min; BUP; 90 min). However, the quality of pain relief during labor and particularly at birth was significantly improved by F (mean VAS in B + F group: 6 mm; mean VAS in BUP group: 42 mm). Mild itching was observed in 43% of patients receiving F, moderate shivering in 13% versus 40% in patients not receiving F. At control mean maternal F plasma levels were not zero but 0.25 ng/ml. After the initial injection and following the first and second top-up dose mean maximum maternal F plasma concentrations were 0.54 ng/ml (+/-0.32; +/-SD), 0.88 ng/ml (+/-0.62) and 1.06 ng/ml (+/-0.4) (range 0.18-2.76 ng/ml), respectively. The increase in maternal F concentrations with increasing injection frequency was statistically significant (P < 0.02). Mean umbilical venous and arterial F concentrations at birth were 0.72 ng/ml (+/-1.16) and 0.62 ng/ml (+/-0.52). No significant group differences were found regarding Apgar scores or umbilical blood gas analyses. In one newborn, radioimmunoassay resulted in unexplainably high umbilical F concentrations without any clinical signs of sedation, depressed vigilance and without any sequellae. DISCUSSION. Repeated addition of 100 micrograms F to epidural anaesthesia with bupivacaine significantly improves analgesia and provides pain relief not only during the fir

Adult↗

[Hypnosis--a side effect-free alternative to medical sedation in regional anesthesia].

Hypnosis can be an alternative to cerebral sedatives with no side effects for sedation during regional anaesthesia, especially in high-risk and fearful patients. Patients who have experience with relating techniques like Jakobson's progressive muscle relaxation are very good candidates for hypnosis. It is contraindicated in patients with psychotic disorders, major depression, and abuse of hallucinogenic drugs. The authors shows his personal method of hypnosis based on fixation and suggestive techniques like muscle relaxation, temperature sensation, and creation of emotional pictures. Of ten cases, hypnosis was successful in six (vegetative stress symptoms like tachycardia or shivering stopped immediately after induction of hypnosis), not completely successful in two (interruption of hypnosis after 30 min) and unsuccessful in two. Four cases where hypnosis was used during spinal anaesthesia for knee and hip surgery or brachial plexus block for open fixation of Colles' fracture are discussed as examples. As it requires more time (15 to 45 min to inform and test the patient) and special organisational conditions hypnosis will not become a routine procedure, but is still a good alternative for selected cases.

Adult↗

[Intraoperative heat conservation. A lot of hot air?].

Thermoregulation and its impairment by anaesthesia and surgery has recently been brought back into focus by researchers and clinicians. All volatile and IV anaesthetics, opioids, as well as spinal and epidural anaesthesia increase the inter-threshold range of thermoregulation from 0.2 degree C to 4 degrees C between vasodilation and vasoconstriction. Thermoregulatory vasoconstriction and shivering occurs in anaesthetized patients at lower core temperatures than in awake subjects. Following induction of general or spinal/epidural anaesthesia, core temperature decreases significantly due to internal redistribution of body heat from the core thermal compartment to peripheral tissues. About 1 h after induction of general anaesthesia and initial redistribution hypothermia, a real reduction in body heat occurs as heat loss exceeds metabolic heat production. Heat loss is further increased due to low operating room temperatures, evaporation from open body cavities, and cold IV fluids. Peripheral thermoregulatory vasoconstriction is triggered by core temperatures between 33 degrees C and 35 degrees C, and is able to slow heat loss. However, body heat content continues to decrease even though core temperatures remain nearly constant. During spinal or epidural anaesthesia thermoregulation remains intact in the unblocked body segments, leading to reduced real heat loss when compared to general anaesthesia. Inadvertent hypothermia markedly decreases drug metabolism. Coagulation is impaired by cold-induced defects of platelet function. Hypothermia reduces neutrophil phagocytosis and oxidative killing capacity, causing wound infections. Postoperative hypothermia represents an unnecessary stress for the circulatory system, elevating plasma catecholamines and leading to myocardial ischaemia and arrhythmias. These hypothermia-related morbidities therefore have consequences reaching fare into the postoperative period. Prevention of inadvertent hypothermia is always indicated. Forced-air warming is the most effective and safest method to prevent perioperative hypothermia.

Body Temperature↗

[Remifentanil with propofol or isoflurane. A comparison of the recovery times after arthroscopic surgery].

OBJECTIVES: Due to its unique pharmacokinetics, the new esterase-metabolised opioid remifentanil results in rapid post-anesthesia recovery. The aim of this clinical investigation was to compare recovery times after remifentanil anaesthesia in combination with hypnotic concentrations of either propofol or isoflurane. Dosages used in the study protocol were based on recommendations by the pharmaceutical manufacturer. METHODS: Patients (ASA status I-II) scheduled for elective arthroscopy were included in this trial. Without premedication in the morning, anaesthesia was induced identically in both groups: remifentanil bolus (1 microgram/kg), start of remifentanil-infusion (0.5 micrograms/kg/min), followed immediately by propofol (ca. 2 mg/kg). For maintenance of anaesthesia remifentanil (0.25 micrograms/kg/min) was combined with either a propofol infusion of 0.1 mg/kg/min or 0.5 MAC isoflurane (= 0.6 vol. %) in O2/air. Anaesthetic delivery was discontinued simultaneously with termination of surgery and recovery times were recorded. RESULTS: A total of 40 patients were studied at random in two groups of 20 each with comparable demographic data and anaesthetic technique (Tables 1 and 2). In both groups emergence was very rapid. Recovery times were significantly shorter for remifentanil-isoflurane than for remifentanil-propofol (Table 3): spontaneous ventilation 5.1 vs 8.1 min (P < 0.05), extubation 5.5 vs 8.6 min (P < 0.02), post-anaesthesia recovery score > or = 9 of 10 points 6.2 vs 11.3 min (P < 0.01), and arrival at PACU 16.2 vs 19.2 min (P < 0.01). Mild to moderate shivering was noted in 40% of all patients (9 cases following isoflurane, 7 following propofol). CONCLUSIONS: Using the manufacturer's recommended dosages, emergence after remifentanil anaesthesia is more rapid with 0.5 MAC isoflurane than with 0.1 mg/kg/min propofol. These results are most probably due to the different pharmacological properties of both co-anaesthetics, especially the applied dosages, and to different interactions with remifentanil. Present clinical experience suggests that a further dose reduction, especially for propofol, is possible. For both remifentanil groups emergence was remarkably rapid between return of consciousness and the awake state (on-off phenomenon), which might contribute to post-anaesthesia safety.

Adult↗

[Remifentanil and alfentanil: Sympathetic-adrenergic effect in the first postoperative phase in patients at cardiovascular risk].

UNLABELLED: Extubation and the immediate postoperative period are critical periods with strong sympatho-adrenergic stimulation. The aim of the present study was to investigate this period after balanced anaesthesia with remifentanil and alfentanil in cardiac risk patients. METHODS: 52 patients with coronary artery disease or with risk factors for coronary heart disease scheduled for elective extraperitoneal and extrathoracic operation were included in this study. Anaesthesia was induced by intravenous administration of etomidate, vecuronium and remifentanil (n = 27, 1 microgram/kg) or alfentanil (n = 25, 25 micrograms/kg). Anaesthesia was maintained with an Isoflurane/N2O/O2 mixture and by continuous intravenous infusion of remifentanil (0.25 microgram/kg/min) or alfentanil (45 micrograms/kg/h). During the first 60 minutes after extubation haemodynamic parameters were monitored and catecholamines were determined at defined time intervals. Parameters of recovery, the requirement of analgesics and cardiac medications were compared in both groups. Myocardial ischaemia was assessed by two-channel Holter electrocardiography. RESULTS: The beginning of spontaneous respiration and time of extubation were similar in both groups. The time interval until opening eyes and the time between the beginning of spontaneous respiration and extubation was shorter in the patients treated with remifentanil. In this group patients suffered earlier from pain and had a higher pain score. Although the plasma catecholamines were comparable in both groups, in the patients treated with remifentanil changes in haemodynamic parameters were more pronounced. The incidence of shivering and the requirements of analgesics and cardiac medications were higher in these patients. The incidence of ST-segment changes indicating myocardial ischaemia was similar. CONCLUSIONS: After balanced anaesthesia with remifentanil a more pronounced sympatho-adrenergic stimulation occurs because of the more rapid clearance of the analgesic effect in the recovery period compared to alfentanil requiring more analgesics and medications for the control of the haemodynamic parameters. Because of these specific pharmacological effects the use of remifentanil in cardiac risk patients has to be critically discussed.

Aged↗

[The use of remifentanil in critically ill patients. Clinical findings and early experience].

OBJECTIVES: It was the aim of this investigation to report our initial clinical experience on the use of remifentanil in critically ill patients undergoing mechanical ventilation. Additionally, we hypothesized that even under intensive care conditions remifentanil might facilitate a temporally predictable and "programmed" tracheal extubation. METHODS: Remifentanil was used for analgesia and sedation of mechanically ventilated patients who were admitted to the ICU following major noncardiac surgery or who had to be ventilated due to respiratory failure. The infusion was started with 0.15 microg/kg/min and then adapted in steps of 0.05 microg/kg/min according to clinical needs. After admission to the ICU the depth of sedation was adjusted to a Ramsay score level of 4 (sleeping patient, immediately arousable) and then targeted at a level of 2-3 (patient awake, co-operative and tranquil or responding to command only). In case of sufficient pain relief but inadequate sedation patients could receive bolus doses of midazolam (1-3 mg) or an infusion of clonidine (0.5 microg/kg/h), the latter especially in case of shivering or hypertension. Prior to extubation bolus doses of piritramide (3-5 mg) and a non-opioid analgesic (metamizol or propacetamol) could be used for postoperative pain relief. Data are presented as mean+/-SD. RESULTS: A total of 46 patients were studied, aged 62.8+/-15.4 yr with a mean APACHE II score of 19.2 points. The duration of remifentanil infusion ranged up to 78 h with a mean of 9. 8 h. The mean infusion rate was 0.14+/-0.08 microg/kg/min during ongoing analgesia and sedation and 0.10+/-0.08 microg/kg/min immediately before its discontinuance. Additional sedatives were necessary in 63% of all patients. Emergence was rapid in the majority of cases: 67% of all patients could safely be extubated within 15 min after termination of remifentanil, and a total of 87% were extubated within 45 min. A development of tolerance was not observed during the study period. CONCLUSIONS: Remifentanil appeared to be suitable for analgesia and sedation of critically ill patients undergoing mechanical ventilation: Even under intensive care conditions recovery was rapid in the majority of cases, and in two thirds of all patients tracheal extubation was temporally predictable and could be timed within 15 min. These results are best explained by the metabolism and offset of action of remifentanil obviously unaffected in the ICU area. However, for fast emergence the cautious use of additional sedatives is crucial.

APACHE↗

[27-year-old man with high fever and septic shock after returning from vacation].

A 27-year-old man was admitted with high fever and shivers eleven days after returning from vacation in Indonesia. Physical examination, laboratory values, abdominal ultrasound, and chest x-ray were not conclusive. All blood cultures yielded growth of Salmonella enterica serovar Typhi, and typhoid fever was diagnosed. Subsequently, the patient developed septic shock and pulmonary edema. In this case report epidemiological, clinical, and therapeutic aspects of typhoid fever are discussed with special emphasis on criteria for severe typhoid fever, which is treated with additional glucocorticoids.

Adult↗

Increased systemic oxygen consumption offsets improved oxygen delivery during dobutamine infusion in newborn lambs.

OBJECTIVE: To determine: 1) if dobutamine elicited a thermogenic response during postnatal development; and 2) if this response impacted on the balance between systemic O(2) delivery (DO(2)) and O(2) consumption (VO(2)), and involved one or a combination of adrenoceptor subtypes. DESIGN: Prospective non-randomized unblinded study. SETTING: University research laboratory. SUBJECTS: Thirty-five Border-Leicester cross lambs used in a main study performed at 1-2 days (n=7), 7-10 days (n=7), and 6-8 weeks (n=8), and in a adrenoceptor blockade substudy performed at 1-2 days (n=13). INTERVENTIONS: Lambs were instrumented under anaesthesia and dobutamine was infused at incremental rates of 1-40 microg/kg per minute. In separate subgroups of 1-2 day-old lambs, dobutamine was infused after selective or combined alpha1, beta 1, and beta 2-adrenoceptor blockade. MEASUREMENTS: Cardiac output, aortic and pulmonary arterial blood gases, and body temperature were measured. DO(2) and VO(2) were calculated. MAIN RESULTS: Dobutamine increased DO(2) similarly at all three ages. Dobutamine also increased VO(2) in the absence of muscle shivering, but the average rise in 1-2 day-old lambs was sevenfold to 12-fold greater (P<0.001) than in 7-10 day-old and 6-8 week-old animals, was associated with an increase in systemic O(2) extraction, and accounted for approximately 90% of the rise in DO(2). Body temperature rose by 1.3+/-0.5 degrees C in 1-2 day-old animals (P<0.001), but was unchanged in 7-10 day-old or 6-8 week-old lambs. In 1-2 day-old lambs, rises in DO(2), VO(2), and body temperature induced by dobutamine were not affected by selective alpha1, beta1 or beta2 adrenoceptor blockade, but were markedly attenuated by combined adrenoceptor blockade. CONCLUSIONS: A substantial rise in VO(2) which accompanied a pronounced thermogenic effect of dobutamine in newborn lambs utilized most of the associated increase in DO(2) and appeared to be dependent on activation of multiple adrenoceptor subtypes.

Adrenergic alpha-1 Receptor Antagonists↗