[The role of non-opioid analgesics in the management of postoperative pain.]

At present, intramuscular application of opioids given on request is the most widespread form of postoperative analgesia. This method is widely recognized as often being inadequate, however. As advanced techniques of pain management, such as patient-controlled analgesia, are not generally available, the question arises as to whether non-opioid analgesics should routinely be used in order to improve this situation. A review of the literature indicates that apart from when used following abdominal surgery, in particular, operations on the biliary tract, non-steroidal anti-inflammatory drugs (NSAIDS) offer effective postoperative pain control. Following minor surgery, the quality of analgesia can be better than that achieved with the weak opioids. The discrepancy between biliary tract operations and all other forms of surgery raises the question whether in the former case pain may have been partly due to spasms of visceral smooth muscle and hence be less readily amenable to the action of NSAIDS. A potential problem with the perioperative use of NSAIDS is that they inhibit platelet aggregation. Apart from tonsillectomy, there are no reports of increased intra- or postoperative bleeding when these drugs have been used for minor surgery, and only isolated reports following major operations. Despite these results, it must be borne in mind that most studies have been carried out on patients of ASA groups I and II and that conclusions drawn from the literature are not necessarily representative for the elderly and for patients with organ failure. Alternative substances have received relatively little attention. Of these, the pyrazolone derivative, metamizol, may well prove to be of value for patients in whom the use of NSAIDS is contraindicated or relatively ineffective such as after biliary tract surgery.

Keine synergistische Wirkung der Kombination von ∆9-Tetrahydrocannabinol und Piritramid bei postoperativen Schmerzen

BACKGROUND

It is concluded from animal experiments that cannabinoid receptor and mu-opioid receptor agonists act synergistically with respect to antinociception. In order to demonstrate this effect under clinical conditions, we conducted a randomized double blind trial with patients after radical prostatectomy.

PATIENTS AND METHODS

From the evening before the operation until the morning of the second postoperative day, all patients received eight oral doses of either placebo or 5 mg Delta(9)-tetrahydrocannabinol (dronabinol). Postoperatively patients had access to patient-controlled analgesia with the micro-opioid agonist piritramide for 48 h. We expected patients receiving dronabinol to require significantly less piritramide compared to patients on placebo.

RESULTS

The consumption of piritramide was recorded in 100 patients after radical retropubic prostatectomy with regional lymphadenectomy. Patients in the placebo group consumed 74 mg (median), interquartile range (IQR) 44-90 mg, patients in the verum group consumed 54 mg (median) IQR 46-88 mg. The difference between groups was not statistically significant. Plasma concentrations of Delta(9)-THC were measurable in all patients in the verum group. The levels (median) were 1.5 ng/ml (IQR 0.6-2.3), 1.3 ng/ml (IQR 0.5-2.2) and 1.9 ng/ml (IQR 0.8-2.7) on the day of operation, the first and second postoperative day, respectively.

CONCLUSION

We found neither a synergistic nor even an additive antinociceptive interaction between Delta(9)-tetrahydrocannabinol and the micro-opioid agonist piritramide in a setting of acute postoperative pain.

[Postoperative analgesia with rofecoxib. How effective is the preoperative application of a 25 mg dose?]

OBJECTIVE

The purpose of this study was to evaluate the analgesic efficacy of 25 mg rofecoxib.

METHODS

In a randomized, prospective double-blind study we investigated the analgesic efficacy of 25 mg rofecoxib in 62 patients scheduled for minor trauma surgery. Patients received 2 h before induction of anesthesia either 25 mg rofecoxib (verum) orally or placebo. These applications were repeated postoperatively after 24 h. Postoperative pain intensity was measured by the numeric rating scale (NRS). All patients were allowed to order piritramid from a PCA-device (bolus 2 mg, lockout 5 min in the recovery room, 15 min on the ward) for 24 h after surgery. 10/20/30 min, as well as 1/2/4/6 h and 24 h after surgery cumulated doses of piritramid, pain scores (0-10) and side effects were recorded.

RESULTS

Pain relief and cumulated doses of piritramid in both groups were comparable at all points in time. There were no significant differences in the incidence of side effects between the two groups.

CONCLUSION

Preoperative application of 25 mg rofecoxib is not effective for postoperative analgesia in patients after minor trauma surgery.

Spinal hematoma: a literature survey with meta-analysis of 613 patients

Spinal hematoma has been described in autopsies since 1682 and as a clinical diagnosis since 1867. It is a rare and usually severe neurological disorder that, without adequate treatment, often leads to death or permanent neurological deficit. Epidural as well as subdural and subarachnoid hematomas have been investigated. Some cases of subarachnoid spinal hematoma may present with symptoms similar to those of cerebral hemorrhage. The literature offers no reliable estimates of the incidence of spinal hematoma, perhaps due to the rarity of this disorder. In the present work, 613 case studies published between 1826 and 1996 have been evaluated, which represents the largest review on this topic to date. Most cases of spinal hematoma have a multifactorial etiology whose individual components are not all understood in detail. In up to a third of cases (29.7%) of spinal hematoma, no etiological factor can be identified as the cause of the bleeding. Following idiopathic spinal hematoma, cases related to anticoagulant therapy and vascular malformations represent the second and third most common categories. Spinal and epidural anesthetic procedures in combination with anticoagulant therapy represent the fifth most common etiological group and spinal and epidural anesthetic procedures alone represent the tenth most common cause of spinal hematoma. Anticoagulant therapy alone probably does not trigger spinal hemorrhage. It is likely that there must additionally be a "locus minoris resistentiae" together with increased pressure in the interior vertebral venous plexus in order to cause spinal hemorrhage. The latter two factors are thought to be sufficient to cause spontaneous spinal hematoma. Physicians should require strict indications for the use of spinal anesthetic procedures in patients receiving anticoagulant therapy, even if the incidence of spinal hematoma following this combination is low. If spinal anesthetic procedures are performed before, during, or after anticoagulant treatment, close monitoring of the neurological status of the patient is warranted. Time limits regarding the use of anticoagulant therapy before or after spinal anesthetic procedures have been proposed and are thought to be safe for patients. Investigation of the coagulation status alone does not necessarily provide an accurate estimate of the risk of hemorrhage. The most important measure for recognizing patients at high risk is a thorough clinical history. Most spinal hematomas are localized dorsally to the spinal cord at the level of the cervicothoracic and thoracolumbar regions. Subarachnoid hematomas can extend along the entire length of the subarachnoid space. Epidural and subdural spinal hematoma present with intense, knife-like pain at the location of the hemorrhage ("coup de poignard") that may be followed in some cases by a pain-free interval of minutes to days, after which there is progressive paralysis below the affected spinal level. Subarachnoid hematoma can be associated with meningitis symptoms, disturbances of consciousness, and epileptic seizures and is often misdiagnosed as cerebral hemorrhage based on these symptoms. Most patients are between 55 and 70 years old. Of all patients with spinal hemorrhage, 63.9% are men. The examination of first choice is magnetic resonance imaging. The treatment of choice is surgical decompression. Of the patients investigated in the present work, 39.6% experienced complete recovery. The less severe the preoperative symptoms are and the more quickly surgical decompression can be performed, the better are the chances for complete recovery. It is therefore essential to recognize the relatively typical clinical presentation of spinal hematoma in a timely manner to allow correct diagnostic and therapeutic measures to be taken to maximize the patient's chance of complete recovery.

[Droperidol and dimenhydrinate alone or in combination for prevention of postoperative nausea and vomiting]

BACKGROUND

Droperidol and dimenhydrinate are inexpensive antiemetic drugs. Droperidol, especially, has been studied extensively in the past, but there are no studies that used the combination of both drugs for prevention of postoperative nausea and vomiting (PONV). Thus, the aim of this randomised controlled and double-blinded study was to evaluate the antiemetic efficacy and the side effects of such a combination therapy.

METHODS

240 inpatients undergoing ENT surgery under general anaesthesia were randomised to receive one of four antiemetic regimes: placebo, dimenhydrinate (1 mg x kg-1), droperidol (15 micrograms x kg-1), or the combination of both drugs (droperidol 15 micrograms x kg-1 + dimenhydrinate 1 mg x kg-1) was administered after induction of anaesthesia and repeated 6 hours after the first administration. For general anaesthesia a standardised technique including benzodiazepine premedication, propofol, desflurane in N2O/O2, vecuronium, and a continuous infusion of remifentanil was used. Postoperative analgesia and antiemetic rescue medication were standardised. Episodes of vomiting, retching, nausea, and the need for additional antiemetics were recorded for 24 hours. The main goal of the study was to increase the number of patients who were completely free from PONV (chi 2-test with Fisher-Yates' correction). Furthermore, the severity of PONV was analysed using a standardised scoring algorithm.

RESULTS

Data of 227 patients could be analysed. The incidence of patients who suffered from PONV was 41.3% (95%-confidence interval: 29-55%) in the placebo-group. Dimenhydrinate alone reduced PONV to 34.5% (95%-CI: 22-48%). This marginal effect and the effect of droperidol (PONV: 26.4% (95%-CI: 15-40%)) could not be proven statistically, since the power of the study was too small. The combination of both drugs decreased PONV to 19.6% (95%-CI: 10-32%) and also reduced the severity of the symptoms to a clinically acceptable level.

CONCLUSION

Dimenhydrinate failed to reduce the incidence and severity of PONV. The efficiency of droperidol given alone was within the ranges previously known from metaanalytic data. The combination of both drugs showed a moderate synergistic effect.

Spinal epidural abscess: a meta-analysis of 915 patients

Spinal epidural abscess (SEA) was first described in the medical literature in 1761 and represents a severe, generally pyogenic infection of the epidural space requiring emergent neurosurgical intervention to avoid permanent neurologic deficits. Spinal epidural abscess comprises 0.2 to 2 cases per 10,000 hospital admissions. This review intends to offer detailed evaluation and a comprehensive meta-analysis of the international literature on SEA between 1954 and 1997, especially of patients who developed it following anesthetic procedures in the spinal canal. In this period, 915 cases of SEA were published. This review is the most comprehensive literature analysis on SEA to date. Most cases of SEA occur in patients aged 30 to 60 years, but the youngest patient was only 10 days old and the oldest was 87. The ratio of men to women was 1:0.56. The most common risk factor was diabetes mellitus, followed by trauma, intravenous drug abuse, and alcoholism. Epidural anesthesia or analgesia had been performed in 5.5% of the patients with SEA. Skin abscesses and furuncles were the most common source of infection. Of the patients, 71% had back pain as the initial symptom and 66% had fever. The second stage of radicular irritation is followed by the third stage, with beginning neurological deficit including muscle weakness and sphincter incontinence as well as sensory deficits. Paralysis (the fourth stage) affected only 34% of the patients. The average leukocyte count was 15,700/microl (range 1,500-42,000/microl), and the average erythrocyte sedimentation rate was 77 mm in the first hour (range 2-50 mm). Spinal epidural abscess is primarily a bacterial infection, and the gram-positive Staphylococcus aureus is its most common causative agent. This is true also for patients who develop SEA following spinal anesthetics. Magnetic resonance imaging (MRI) displays the greatest diagnostic accuracy and is the method of first choice in the diagnostic process. Myelography, commonly used previously to diagnose SEA, is no longer recommended. Lumbar puncture to determine cerebrospinal fluid protein concentrations is not needed for diagnosis and entails the risk of spreading bacteria into the subarachnoid space with consequent meningitis; therefore, it should not be performed. The therapeutic method of choice is laminectomy combined with antibiotics. Conservative treatment alone is justifiable only for specific indications. Laminotomy is a therapeutic alternative for children. The mortality of SEA dropped from 34% in the period of 1954-1960 to 15% in 1991-1997. At the beginning of the twentieth century, almost all patients with SEA died. Parallel to improvements in the mortality rate, today more patients experience complete recovery from SEA. The prognosis of patients who develop SEA following epidural anesthesia or analgesia is not better than that of patients with noniatrogenic SEA, and the mortality rate is also comparable. The essential problem of SEA lies in the necessity of early diagnosis, because only timely treatment is able to avoid or reduce permanent neurologic deficits. The problem with spinal epidural abscesses is not treatment, but early diagnosis - before massive neurological symptoms occur" (Strohecker and Grobovschek 1986).

Dimenhydrinate and metoclopramide alone or in combination for prophylaxis of PONV

PURPOSE

Dimenhydrinate and metoclopramide are inexpensive antiemetic drugs. Metoclopramide, especially, has been studied extensively in the past, but there are no studies on the combination of both drugs for prevention of postoperative nausea and vomiting (PONV).

METHODS

One hundred and sixty male inpatients undergoing endonasal surgery were randomized to receive one of four antiemetic regimens in a double-blind manner: placebo, 1 mg x kg(-1) dimenhydrinate, 0.3 mg x kg(-1) metoclopramide, or the combination of both drugs was administered after induction of anesthesia. Patients received a second dose of these drugs six hours after the first administration to mitigate their short half-life. Standardized general anesthesia included benzodiazepine premedication, propofol, desflurane in N2O/O2 vecuronium, and a continuous infusion of remifentanil. Postoperative analgesia and antiemetic rescue medication were standardized. Episodes of vomiting, retching, nausea, and the need for additional antiemetics were recorded for 24 hr. The incidences of PONV were analyzed with Fisher's Exact test and the severity of PONV (rated by a standardized scoring algorithm) with the Jonckheere-Terpestra-test.

RESULTS

The incidence of patients free from PONV was 62.5% in the placebo-group and increased to 72.5% in the metoclopramide-group (P = 0.54), 75.0% in the dimenhydrinate-group (P = 0.34), and 85.0% in the combination- group (P = 0.025). In the latter group, the severity of PONV was reduced compared with placebo treatment (P = 0.017; Jonckheere-Terpestra-test).

CONCLUSION

Dimenhydrinate and metoclopramide were ineffective in reducing the incidence and the severity of PONV. Their combination reduced the incidence of PONV compared with placebo.

Evaluation of three risk scores to predict postoperative nausea and vomiting

BACKGROUND

So far there are three different scores to predict postoperative vomiting (PV: Apfel et al., 1998) or postoperative nausea and vomiting (PONV: Koivuranta et al., 1997; Palazzo and Evans, 1993). All three scores used logistic regression analysis to identify and create weights for the risk factors for PV or PONV. In short, these were sex, age, history of previous PONV, motion sickness, duration of anaesthesia, and use of postoperative opioids. However, an external evaluation and a comparison of these scores has not been performed so far.

METHODS

Patients undergoing a variety of surgical procedures under general anaesthesia were studied prospectively. Preoperatively, they completed a questionnaire concerning potential risk factors for the occurrence of PV or PONV implemented in the three risk scores. Balanced anaesthesia (induction agent, nondepolarising neuromuscular blocker, opioid, and inhalation agent in nitrous oxide/oxygen) was performed. No intravenous anaesthesia or any antiemetic prophylaxis was applied. Postoperatively, the patients were observed in the recovery room for the occurrence of PV and PONV and were visited twice on the ward within the 24-h observation period. Both the patients and the nursing staff were asked whether PV or PONV was present. The severity of PONV was categorised using a standardised scoring algorithm. A total of 1,444 patients was finally included into the analysis. Using information of the predicted risk for the individual patients and the actual occurrence of PV or PONV, Receiver Operator Characteristics (ROC-curves) were drawn. The area under each ROC-curve was calculated as a means of the predictive properties of each score and was compared for statistical differences.

RESULTS

For prediction of PONV (any severity) the AUC-values (AUC=area under the curve) and the corresponding 95%-confidence intervals were: Apfel: 0.70 (0.67-0.72); Koivuranta: 0.71 (0.69-0.73); Palazzo: 0.68 (0.65-0.70). For prediction of PV: Apfel: 0.73 (0.71-0.75); Koivuranta: 0.73 (0.70-0.75); Palazzo: 0.68 (0.65-0.70). Thus, all three scores appeared to have a moderate accuracy as measured by the AUC. The score of Koivuranta predicts PONV (P=0.007) and also PV (P=0.002) significantly better than Palazzo's score. Furthermore, for predicting of PV the score of Apfel was also superior to Palazzo's score (P=0.005). All three scores predict PV with the same accuracy as PONV.

CONCLUSION

The occurrence of PV and PONV in patients undergoing surgery under balanced anaesthesia can be predicted with moderate but acceptable accuracy using one of the available risk scores, regardless of local surgical or anaesthesiological circumstances. For clinical practice, we recommend the score published by Koivuranta, since its calculation is very simple.

Droperidol and dimenhydrinate alone or in combination for the prevention of post-operative nausea and vomiting after nasal surgery in male patients

Droperidol and dimenhydrinate are inexpensive antiemetic drugs. Droperidol, especially, has been studied extensively, but there are no studies on the combination of both drugs for prevention of post-operative nausea and vomiting. One hundred and forty male hospitalized patients undergoing nasal surgery were randomized to receive one of four anti-emetic regimes: placebo, dimenhydrinate (1 mg kg-1), droperidol (15 micrograms kg-1), or the combination of both drugs (droperidol 15 micrograms kg-1 + dimenhydrinate 1 mg kg-1) administered after induction of anaesthesia. Patients in the dimenhydrinate-group and the combination-group received a second dose of dimenhydrinate 6 h after the first administration to mitigate the short half-life of the drug. For general anaesthesia a standardized technique, including benzodiazepine premedication, propofol, desflurane in N2O/O2, vecuronium, and a continuous infusion of remifentanil, was used. Post-operative analgesia and anti-emetic rescue medication were standardized. Episodes of vomiting, retching, nausea, and the need for additional anti-emetics were recorded for 24 h. The main endpoint of this study was the number of patients who were completely free of post-operative nausea and vomiting (Fisher's Exact Test). Furthermore, the severity of post-operative nausea and vomiting was analysed using a standardized scoring algorithm. The incidence of patients completely free of post-operative nausea and vomiting was 62.9% in the placebo-group, 77.1% in the dimenhydrinate-group (P = 0.21), and 82.9% in the droperidol-group (P = 0.07). This increased to 94.3% in the combination-group (P = 0.0015). In all three treatment groups the severity of post-operative nausea and vomiting was reduced significantly compared with placebo treatment (P = 0.0003). The incidence of side effects was similar in the four groups. Dimenhydrinate was ineffective in reducing the incidence of post-operative nausea and vomiting and droperidol only reduced the severity of post-operative nausea and vomiting. However, the combination of both drugs significantly reduces the incidence of post-operative nausea and vomiting when compared with placebo treatment.

[Meta-analysis of controlled randomized studies on droperidol for prevention of postoperative phase vomiting and nausea]

OBJECTIVE

Randomised, controlled trials using prophylactic droperidol to prevent postoperative nausea and vomiting (PONV) were included in a meta-analysis to estimate efficiency and dose-response of treatment.

MATERIALS AND METHODS

Studies were systematically extracted from Medline, the manufacturer's database, and a supplemental search of references lists and current issues of locally available anaesthesia journals. Complete prevention of PONV defined as absence of nausea, retching, and vomiting within 6 hours (early PONV) and within 48 hours (late PONV) was chosen as the main end point. Additional information such as dose of droperidol, time and way of administration, and biometric data of the patients were extracted from each study. The pooled relative risk and the number-needed-to treat (NNT) were calculated.

RESULTS

A total of 72 studies with 107 comparative subgroups were accepted for analysis according to the prospectively defined criteria. Of these sixty-nine trials reported a lower incidence of PONV with droperidol. The incidence of early and late PONV among the 5370 patients receiving droperidol was 23.4% and 38.2%, respectively. The corresponding incidence among the 3954 control patients was 40.7% and 53.9%. The relative risk for patients receiving prophylactic droperidol of suffering from early PONV was 0.58 and 0.71 for late PONV. The NNT for preventing one patient from PONV was 5.8 and 6.4 for early and late PONV, respectively. Treatment with droperidol was more effective when the baseline risk for PONV was higher than 25% for early PONV and 35% for late PONV. Under these circumstances the NNT was between 2.6 and 5.6. There was no dose response relationship for droperidol when the drug was applied in doses ranging from 0.5 to 300 micrograms.kg-1 body weight. It was not possible to derive reliable information about the incidence of side-effects of the droperidol administration.

CONCLUSION

Droperidol is an effective antiemetic drug. The drug can be administered to patients with an increased risk of suffering from PONV without antiemetic prophylaxis. Since a positive dose response is lacking, droperidol should only be administered in doses of 1 mg or less.

[Validation of a risk score for prediction of vomiting in the postoperative period]

BACKGROUND

A risk score to predict postoperative vomiting was presented in a recent issue of this journal. In the present study this score was evaluated at another hospital under different surgical and anaesthetic conditions. Furthermore, we examined whether the score, which was originally designed to predict the occurrence of postoperative vomiting (POV) only, is also useful for prediction of postoperative nausea and vomiting (PONV).

METHODS

The risk score was applied to 226 patients undergoing inpatient orthopaedic surgery under standardised general anaesthesia (propofol, desflurane in N(2)O/O(2), fentanyl, vecuronium, postoperative opioid analgesia). For 24 hours postoperatively, the patients were followed up for the occurrence of nausea, retching, and vomiting. Perioperatively, risk factors for POV were recorded (gender, age, smoking habits, history of previous PONV or motion sickness, duration of anaesthesia). Using these risk factors the individual risk for suffering POV was calculated for each patient. With these data two ROC-curves (for prediction of POV and PONV respectively) were constructed and the area under the ROC-curve (AUC) as a means of the prediction probabilities of the score was calculated.

RESULTS

The incidence of POV as predicted by the score (22,8%) fits well to the actual incidence of this event (19,5%). The score predicts the occurrence of POV significantly better than can be expected by a random estimation. In spite of different surgical and anaesthetic conditions, the accuracy of the prediction in the present dataset was not significantly different from that reported by the authors of the scores in their validation set. Furthermore, the prediction properties for POV (AUC: 0,73) were not different from the prediction of PONV (AUC: 0,72).

CONCLUSION

The present risk score provides valid prognostic results even under modified surgical and anaesthetic conditions, and, thus, may obviously be applied to other institutions. Furthermore our results support the hypothesis, that individual risk factors rather than the type of surgery or anaesthetic management have a major impact on the occurrence of POV and PONV.

[Dimenhydrinate and metoclopramide for prevention of nausea and vomiting following septorhinoplasties in women]

OBJECTIVES

Dimenhydrinate and metoclopramide are inexpensive antiemetic drugs. Metoclopramide, especially, has been studied extensively in the past, but there are no studies that used the combination of both drugs for prevention of postoperative nausea and vomiting (PONV).

METHODS

120 female inpatients undergoing endonasal surgery were randomised to receive one of four antiemetic regimes: placebo, dimenhydrinate (1 mg x kg-1), metoclopramide (0.3 mg x kg-1), or the combination of both drugs (1 mg x kg-1 + 0.3 mg x kg-1) were administered intravenously after induction of anaesthesia and repeated 6 hours after the first administration. For general anaesthesia a standardised technique including benzodiazepine premedication, propofol, desflurane in N2O/O2 vecuronium and a continuous infusion of remifentanil was used. Postoperative analgesia (diclofenac or metamizole supplemented with piritramide) and antiemetic rescue medication (dolasetron and droperidol) were standardised. Episodes of vomiting, retching, nausea, and the need for additional antiemetics were recorded in the recovery room and 2, 5, 8, and 24 hours after surgery. The main goal of the study was to increase the number of females staying completely free from PONV (Chi 2-test). Furthermore, the severity of PONV was analysed, using a standardised scoring algorithm.

RESULTS

There were no differences between the two groups with regard to biometric data and distribution of risk factors for developing PONV. In all four groups nearly the similar number of patients stayed completely free from PONV: Placebo: 60.7%, metoclopramide: 66.7%, dimenhydrinate: 64.3%, combination: 64.4% (differences not significant). There was also no difference in the severity of nausea and emetic sequel.

DISCUSSION

In females undergoing endonasal surgery under propofol-desflurane-remifentanil anaesthesia the incidence of PONV is about 40%. In this setting, both metoclopramide and dimenhydrinate were ineffective to reduce the incidence and the severity of PONV. The combination of both drugs revealed no additional synergistic effect.

[Dolasetron, droperidol and a combination of both in prevention of postoperative nausea and vomiting after extracapsular cataract extraction under general anesthesia]

BACKGROUND

Both, droperidol and the new 5-HT3-antagonist (e.g. dolasetron) are effective drugs in the prevention of postoperative nausea and vomiting (PONV). It was the aim of this prospective double blind placebo controlled study to determine the efficacy of low-dose droperidol, dolasetron, and a combination of both drugs in the prevention of PONV after extracapsular cataract extraction.

METHODS

148 inpatients undergoing cataract surgery were stratified according to gender and then randomised to receive one of four antiemetic regimens: placebo, droperiodol (10 micrograms x kg-1), dolasetron (12.5 mg), or the combination of both drugs (10 micrograms x kg-1 + 12.5 mg). The drugs were administered intravenously 5-10 minutes before the end of anaesthesia. General anaesthesia and the perioperative management of the patients were standardised: benzodiazepine premedication, induction with etomidate, alfentanil and mivacurium. Maintenance using desflurane in N2O/O2, and a continuous infusion of mivacurium was used. Postoperative analgesia (diclofenac or paracetamol) and antiemetic rescue medication (dimenhydrinate and metoclopramide) was standardised. Nausea, episodes of vomiting, retching and the need for additional antiemetics were recorded for 24-hours. The severity of PONV was categorised using a standardised scoring algorithm. The main aim of the study was the number of patients who stayed completely free from PONV.

RESULTS

There were no differences between the two groups with regard to biometric data, type of surgery, and distribution of risk factors for developing PONV. In all three treatment groups significantly less patients suffered from PONV (placebo: 66%; droperidol: 89%, dolasetron: 92%, combination: 89%; p = 0.011). Furthermore, the severity of PONV was reduced (p = 0.012).

CONCLUSION

Low-dose droperidol and dolasetron are equally effective to reduce the incidence of PONV after cataract surgery under general anaesthesia. The combination of both drugs revealed no additional effect.

Dimenhydrinate for prevention of post-operative nausea and vomiting in female in-patients

Dimenhydrinate is an inexpensive antihistaminic drug, that is frequently used as an anti-emetic during anaesthesia. The popularity of the drug is contrasted by the lack of modern studies concerning its efficacy in reducing the incidence of post-operative nausea and vomiting. Thus, dimenhydrinate was compared with placebo in this prospective, randomized, double-blind study. One hundred and thirty-three female in-patients were studied. They were stratified according to the type of surgery (laparoscopic cholecystectomy, thyroid resection or knee arthroscopy) to ensure an homogeneous distribution in both groups. General anaesthesia was induced with etomidate, fentanyl, vecuronium and maintained with enflurane in N2O/O2. Neuromuscular block was reversed with pyridostigmine/atropine. Patients in the dimenhydrinate group (n = 67) received 62 mg dimenhydrinate intravenously after induction of anaesthesia. Placebo patients (n = 66) received saline. Administration of dimenhydrinate (and placebo) was repeated three times during the 48-h study to mitigate the short half-life of the drug. Post-operative analgesia and anti-emetic rescue medication was standardized. Episodes of vomiting, retching and the need for additional anti-emetics were recorded. Nausea was assessed using a 10-cm visual analogue scale. Post-operative nausea and vomiting was rated as 'none', 'mild', 'moderate' and 'severe' using a fixed scoring algorithm. There were no differences between the two groups with regard to biometric data, type of surgery and distribution of risk factors for developing post-operative nausea and vomiting. In the dimenhydrinate group, more patients remained completely free from post-operative nausea and vomiting compared with placebo (dimenhydrinate: 38.8%; placebo: 15.1%; P = 0.004). The incidence of severe post-operative nausea and vomiting was also reduced from 39.4% to 14.9%. No relevant side effects were observed. Intra-operative dimenhydrinate, followed by three further administrations after surgery, reduces the incidence and the severity of post-operative nausea and vomiting without side effects. However, there still remained an unacceptable high number of patients who were not prevented completely from experiencing post-operative nausea and vomiting.

Droperidol-supplemented anaesthesia decreases post-operative nausea and vomiting but impairs post-operative mood and well-being

Post-operative nausea and vomiting is distressing for patients and can cause dissatisfaction and impaired well-being in the post-operative period. This study examined the question whether the reduced incidence of post-operative nausea and vomiting inevitably translates into improved clinical status and well-being. In this context high doses of droperidol were investigated. On the one hand, droperidol is known to be a powerful anti-emetic, but on the other hand there is concern about psychological effects, both in the pre- and the post-operative period. In this prospective randomized double-blinded study, droperidol (5-7.5 mg) was compared with midazolam (5-7.5 mg) used to supplement fentanyl-N2O based anaesthesia, with respect to post-operative mood and well-being using a psychological questionnaire (Bf-S-test). Furthermore, the incidence of post-operative nausea and vomiting was recorded. Out of 160 patients undergoing thyroidectomy and laparoscopic cholecystectomy, data from 150 patients were analysed. The administration of droperidol significantly lowered the incidence of post-operative nausea and vomiting from 77.8% to 55.1% compared with midazolam (P = 0.0059; chi 2-test). Although post-operative nausea and vomiting is an independent risk factor for post-operative discomfort and bad mood, patients receiving droperidol showed impaired well-being 6 h after surgery. Well-being scores returned to pre-operative base-line values and did not differ between the two groups 24 and 48 h post-operatively. The reduced incidence of post-operative nausea and vomiting achieved with high dose droperidol does not equate with increased post-operative well-being. It is an important point at issue to decide whether smaller doses of droperidol that are commonly used for anti-emetic therapy are free of these side effects.

Changes in gastric intramucosal pH following mesenteric traction in patients undergoing pancreas surgery

BACKGROUND/AIM

During major abdominal surgery, mesenteric traction (MT) may result in hemodynamic instability mainly due to endogenous prostacyclin release. Gastric intramucosal pH (pHi) and PiCO2 are indicators of splanchnic tissue perfusion with a predictive value for the postoperative outcome. We investigated the influence of MT on gastric pHi and on postoperative outcome in patients undergoing pancreas surgery.

METHODS

Forty-six consecutive patients scheduled for pancreas surgery were investigated. We registered hemodynamics and pHi by gastric tonometry and documented postoperative outcome (complications, hospital stay). Baseline data (T0) were recorded after skin incision. Further assessments followed 30, 60 and 120 min after intentional MT (T1-3) and at the end of surgery (T4).

RESULTS

Thirty-three patients demonstrated a decrease in mean arterial pressure (MAP) following MT, whereas 13 patients showed entirely stable hemodynamics. The significant reduction in MAP in patients with an MT response was not associated with changes in pHi as compared to patients with no response (stable MAP) (T0 7.34 +/- 0.08 vs. 7.35 +/- 0.06; T1 7.34 +/- 0.05 vs. 7.32 +/- 0.07; T2 7.32 +/- 0. 05 vs. 7.31 +/- 0.08; T3 7.32 +/- 0.05 vs. 7.32 +/- 0.07; T4 7.26 +/- 0.1 vs. 7.27 +/- 0.08; mean +/- SD, MT response vs. no response). Neither MT response nor gastric intramucosal acidosis as evidenced by a pHi <7.32 at the end of surgery predicted postoperative complications or longer hospital stay.

CONCLUSION

No deterioration of gastric pHi was found, which could reflect acceptable splanchnic perfusion and oxygenation despite systemic blood pressure reactions in patients experiencing an MT response.

Magnetic resonance epidurography with gadolinium-DTPA

The aim of this study was to evaluate and describe MRI epidurography as a new imaging tool. Five volunteers and one patient were investigated with MR epidurography after injection of 20 ml Gd-DPTA solution (1:250/1 ml Gd-DPTA/250 ml normal saline). Magnetic resonance epidurography is possible. With fat-suppression techniques, the contrast between Gd-DPTA solution in the epidural space and surrounding soft tissue proved adequate. Using the multiplanar capability of MRI with MR epidurography coronal and sagittal projections similar to conventional epidurography, axial slices comparable to CT epidurography can be obtained. Magnetic resonance epidurography is superior to conventional and CT epidurography. Presently, due to high costs as compared with conventional and CT epidurography, MRI is not suitable for the routine monitoring of peridural catheters, but it may have a place in the future with decreasing costs for MRI and for the evaluation of patients with spine pathology, especially in describing epidural processes.

Vasopressor hormone response following mesenteric traction during major abdominal surgery

BACKGROUND

We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI2) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia.

METHODS

In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGF1 alpha (stabile metabolite of PGI2), TXB2 (stabile metabolite of thromboxane A2) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection.

RESULTS

Following MT, arterial hypotension occurred along with a substantial PGI2 release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF1 alpha (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P = 0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB2 (164 (87) vs. 58 (1) ng/L, P = 0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P = 0.001), AVP (41 +/- (18) vs. 12 (7) ng/L, P = 0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients.

CONCLUSION

Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI2 release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A2, presumably contributing to hemodynamic stability within 30 min after MT.

[Results of a survey of anesthetists on postoperative nausea and vomiting]

OBJECTIVE

Although an increasing number of studies concerning postoperative nausea and vomiting (PONV) have been performed, we do not know, what anaesthesiologists think about this problem and how they handle it in their daily routine.

METHODS

A survey was performed involving anesthesiologists at 30 institutions of different size. 474 out of 1000 questionnaires were returned.

RESULTS

When asked what kind of general anaesthesia they prefere in a woman at a very high risk to suffer PONV, the following answers were obtained: anaesthesia induction with propofol (78%), thiopentone (17%), etomidate (5%). Maintenance of anaesthesia with an inhalation anesthetic (44%) or with propofol (44%). The remaining 14% would use a combination of these techniques (6%) or neuroleptanaesthesia with droperidol (5%) or midazolam (1%). Only 10% of the respondants would omit nitrous oxide. There is no consensus about the optimal amount of intraoperative opioids. Fentanyl, alfentanil, and sufentanil are rated to contribute equally to the occurence of PONV, whereas opioids used for postoperative analgesia are thought to have substantial differences: piritramid is rated to be much less emetogenic than tramadol and morphine. 70% advocate routine antiemetic prophylaxis for high-risk patients (most often mentioned risk factors were: female sex: 85%, obesity: 81%, high doses of intraoperative opioids: 72%) and 23% administrate antiemetics even for all patients. Ondansetron and droperidol are suggested to be superior to metoclopramide, triflupromazine, dimenhydrinate, and transdermal scopolamine. However, metoclopramide is the drug of first choice for more than 50% of the respondants followed by droperidol, whereas only 29% use ondansetron as a first line drug. An unexpected high number of anaesthesiologists (13%) have experience with non-pharmacological methods for prophylaxis and treatment of PONV. Acupuncture/acupressure (10%) was most often mentioned.

CONCLUSION

A great majority (93%) stated, that PONV is a relevant problem, that still remains unsolved. This proofs the need for further controlled studies.

Therapeutic suggestions given during neurolept-anaesthesia decrease post-operative nausea and vomiting

A double-blind randomized study was performed in 100 patients undergoing thyroidectomy to evaluate the effect of positive therapeutic suggestions made during neurolept-anaesthesia. The classic droperidol-fentanyl-N2O technique was used as these drugs preserve the neurophysiological functions required to process the information in the therapeutic suggestions given during general anaesthesia. Patients in the suggestion group heard positive non-affirmative suggestions during the whole operation. An autoreverse tape player was used. The control group listened to an empty tape. Both groups were comparable with respect to demographic variables, anaesthetic technique, drug dosage, duration of anaesthesia and surgery. Patients in the suggestion group suffered significantly less from post-operative nausea or vomiting (suggestion: 47.2% vs. control: 85.7%) and required less anti-emetic treatment (suggestion: 30.6% vs. control: 68.6%). We conclude that therapeutic suggestions heard during neurolept-anaesthesia are processed and decrease post-operative nausea and vomiting in patients after thyroidectomy.

Ibuprofen does not impair renal function in patients undergoing infrarenal aortic surgery with epidural anaesthesia

OBJECTIVE

To investigate the effect of preoperative ibuprofen administration on renal function during and after infrarenal aortic surgery under thoracolumbar epidural anaesthesia (EPA).

DESIGN

A prospective randomised, double-blinded clinical study.

SETTING

Operation room and intensive care unit in a university hospital.

PATIENTS

Twenty-six consecutive patients scheduled for elective infrarenal aortic surgery.

INTERVENTIONS

The patients were prospectively randomised to receive 400 mg ibuprofen intravenously (i.v.) or a placebo aliquot before surgery.

MEASUREMENTS AND RESULTS

We assessed renal function by calculating creatinine clearance, and fractional sodium excretion before surgery (baseline), 1 h after cross-clamping (intraoperative), 6 h after cross-clamping (postoperative) and 24 h after cross-clamping (on the 1 st postoperative day). At each point in time, we additionally registered haemodynamics and determined the plasma concentration of 6-keto-PGF1alpha (stable metabolite of prostacyclin, PGI2), bicyclic PGE2 (stable metabolite of PGE1 E2), active renin, aldosterone and vasopressin by radioimmunoassays. Throughout the observation period the renal function parameters mostly remained within the normal range without a significant difference between ibuprofen- and placebo-treated patients (creatinine clearance: baseline 41 +/- 3 vs 38 +/- 6, intraoperative 57 +/- 8 vs 64 +/- 11, postoperative 64 +/- 9 vs 56 +/- 9, first postoperative day 43 +/- 5 vs 47 +/- 6 ml x min x m(-2), means +/- SEM). The plasma levels of 6-keto-PGF1alpha (68 +/- 8 vs 380 +/- 71* ng x l(-1)), bicyclic PGE2 (57 +/- 5 vs 88 +/- 9* ng x l(-1)) and vasopressin (14 +/- 7 vs 45 +/- 10* ng x l(-1), p < 0.0125), however, were significantly higher during the intraoperative period in the placebo-treated patients.

CONCLUSION

The inhibition of endogenous prostaglandin release by ibuprofen does not substantially impair renal function during infrarenal aortic surgery under EPA.

[Epiduritis after long-term pain therapy with an epidural catheter--review of the literature with a current case report]

Patients suffering from vascular disease are often a challenge for the acute pain service. Ischaemia, impaired wound healing, stump and phantom limb pain often require a complex analgesic regimen. Invasive measures such as spinal or epidural catheters can be very helpful but carry the risk of infection, as shown by this case report. A 53-year-old woman with a ten-year history of diabetes developed arterial vascular disease. Her right lower leg had been amputated two years previously. She was now admitted with necroses of the left forefoot. A bypass operation was performed under general anaesthesia. Because of intractable ischaemic pain, she was provided with an epidural catheter by the acute pain service. The bypass occluded, however, and a few days later her left lower leg also had to be amputated, this operation being performed under epidural anaesthesia with bupivacaine. The catheter was subsequently used for postoperative pain control and as a means to prevent phantom limb pain. When signs of superficial catheter infection were noticed days later, the catheter was immediately removed. Intractable pain then developed in the left leg which could not be sufficiently controlled with opioids and NSAIDs, and so a second epidural catheter was inserted one segment rostrally. Several days later the infected vascular prosthesis had to be removed followed by amputation of the thigh, this operation also being performed in epidural anaesthesia. Eleven days after insertion of the first epidural catheter, the patient complained of low back pain and headache. Examination by a neurologist revealed no signs of intraspinal infection. The second epidural catheter dislocated at this point in time and it was decided to introduce a third one, this being the only means to treat the otherwise intractable stump pain. Ten days later meningism, Kernig's sign and leucocytosis developed. NMR tomography detected intraspinal fluid in the epidural space at the dorsal border of the spinal canal. A hemilaminectomy was performed. The spinal epidural space showed signs of inflammation of the adipose tissue, but no pus. A little necrotic material and residues of an old haematoma were removed and the epidural space was lavaged. Specimens taken from the epidural material revealed colonisation with staphylococcus epidermidis, which was sensitive to the broad spectrum antibiotics formerly given to the patient to treat the infection in the left stump. By the next day, all signs of epiduritis had disappeared and the patient recovered completely.

Epidural bolus clonidine/morphine versus epidural patient-controlled bupivacaine/sufentanil: quality of postoperative analgesia and cost-identification analysis

We compared the costs, quality of analgesia, and side effects of postoperative patient-controlled epidural analgesia (PCEA) with bupivacaine/sufentanil versus an epidural bolus (BOLUS) of clonidine/morphine in 68 patients with pancreatic surgery. Postoperative pain treatment was performed over 4 days: the PCEA pump was filled with bupivacaine 0.25% and sufentanil 2 micrograms/mL and set to 3-mL bolus and 10-min lockout time. BOLUS patients received injections of clonidine 150 micrograms plus morphine 2 mg on demand. Visual analog scale (VAS) score at rest and during coughing, heart rate (HR), systolic arterial pressure (SAP), incidence of postoperative nausea and vomiting, pruritus, duration of intestinal paralysis, hospital treatment, and costs for personnel and material were recorded. VAS scores during coughing (3 +/- 2.5 vs 5 +/- 3, P < 0.001) was higher, and HR (79 +/- 13 vs 89 +/- 15, P < 0.001), and SAP (110 +/- 18 vs 124 +/- 23, P < 0.001) were lower, in the BOLUS compared with the PCEA group. The incidence of hypotension (SAP < 80 mm Hg) was greater (6 vs 0, P < 0.001) in the BOLUS group. The incidence of all other side effects was comparable. The costs of personnel ($204 +/- $40 vs $166 +/- $38, P < 0.001) were higher in the BOLUS group, but the costs of material ($51 +/- $17 vs $87 +/- $18, P < 0.001) were higher in the PCEA group. Total costs ($62 +/- $9 vs $62 +/- $11 per day, P = 0.9) were comparable. We conclude that because of superior analgesia and reduced side effects at analogous costs, PCEA is preferable to the BOLUS technique for the treatment of postoperative pain.

IMPLICATIONS

An epidural clonidine/morphine bolus technique resulted in inferior analgesia, more side effects, and comparable costs compared with a bupivacaine/sufentanil patient-controlled regimen in a randomized controlled trial after abdominal surgery.

[Differential indications for non-opioids for postoperative analgesia III. Analgesic effect of perioperative administration of metamizole plus diclofenac after spinal anesthesia]

PURPOSE

In a previous study we investigated the analgesic efficacy of a combination of metamizol plus diclofenac after general anaesthesia. After minor orthopaedic surgery postoperative opioid requirements were reduced by 73% during the first 24 h after surgery. In the present study, we have investigated the efficacy of this analgesic combination after minor orthopaedic operations performed in spinal anaesthesia.

METHODS

Seventy four patients, scheduled for minor orthopaedic surgery, participated in this double-blind, randomised, placebo-controlled study. The setting was comparable to our previous study. Before induction of spinal anaesthesia, verum-treated patients received a diclofenac suppository (100 mg), and metamizol (1 g/100 ml NaCl 0.9% intravenously over 15 min). These infusions were repeated at 6 h and 12 h. In addition to the third infusion, the patients received a further diclofenac suppository (100 mg). Cumulated doses of buprenorphine (PCA, patient-controlled analgesia), pain scores (0-10), blood pressure, heart rate and side effects were recorded during the first 6 h and again at 24 h.

RESULTS

After spinal anaesthesia had subsided, all patients required increasing doses of buprenorphine. Verum-treated patients required significantly lower doses during the first 24 h after surgery (median -29%).

CONCLUSIONS

The combination of metamizol and diclofenac causes a clinically relevant reduction in opioid requirements after minor orthopaedic surgery in spinal anaesthesia.

[Postoperative analgesia after endoscopic abdominal operations. A randomized double-blind study of perioperative effectiveness of metamizole]

In comparison to conventional operating technique endoscopic surgery reveals numerous advantages, particular rapid mobilisation and earlier discharge from observation. For a effective utilization of these advantages, it is desirable to have a efficient postoperative analgesic scheme, which can be continued into the period after discharge from hospital. In a randomised, prospective double-blind study we investigated the analgesic efficacy of dipyrone in 40 patients, scheduled for endoscopic abdominal surgery (mainly endoscopic cholecystectomy). Patients received before induction of anesthesia either dipyrone (1 g/100 ml NaCl i.v.) or placebo (100 ml NaCl i.v.). These infusions were repeated 6 h and 12 h after first application. After surgery all patients were allowed to self-administer buprenorphine intravenously from a PCA-pump (Bolus 30 micrograms, lockout 5 min in the recovery room, 30 min on the ward). Every hour for the first 6 h and after 24 h, cumulated doses of buprenorphine, pain scores (0-10), pulse, blood pressure and side effects were recorded. Dipyrone-treated patients had significantly less pain immediately after surgery and used a significantly lower cumulated dose of buprenorphine (-67%; 90 micrograms vs. 270 micrograms buprenorphine) in the first 24 h after surgery.

The impact of prostanoids on pulmonary gas exchange during abdominal surgery with mesenteric traction

We investigated the effect of intravenous (iv) ibuprofen on prostanoid release and on pulmonary gas exchange after abdominal mesenteric traction (MT) during either abdominal aortic surgery or pancreas resection. In a prospective, randomized, double-blind study, 400 mg ibuprofen (pancreas n = 13, aorta n = 13) or a placebo (pancreas n = 13, aorta n = 13) was administered iv before skin incision. MT was applied uniformly. The prostanoid plasma concentrations, venous admixture (Q(va)/Q(t)), and PaO2/FIO2 ratio were determined at baseline (before MT) and 5, 15, 45, and 90 min after MT. Patients who underwent aortic surgery were older and exhibited a lower preoperative PaO2 than those who underwent pancreas resection. Placebo-treated patients revealed a 30-fold peak increase in 6-keto-prostaglandin F1alpha (stable metabolite of prostacyclin) levels after intentional MT during aortic as well as pancreatic operations. This response was accompanied by an increase in Q(va)/Q(t) (ibuprofen: pancreas 7% +/- 1%, aorta 14% +/- 2%; placebo: pancreas 16% +/- 3%, aorta 26% +/- 3%/15 min after MT [mean +/- SEM, P < 0.05, placebo vs ibuprofen]), which resulted in decreased PaO2/ FIO2 ratio only in the aortic surgery patients (ibuprofen: 310 +/- 19; placebo: 237 +/- 24 15 min after MT, [mean +/- SEM, P < 0.05]). The authors conclude that ibuprofen-pretreated patients demonstrated almost constant prostanoid levels without changes in pulmonary gas exchange after MT.

[Effectiveness, side effects and costs of postoperative pain therapy: intravenous and epidural patient-controlled analgesia (PCA)]

PURPOSE

Improvement of the quality of analgesia, reduction of side effects and costs by application of epidural (PCEA) in comparison to intravenous patient-controlled analgesia (PCA) in postoperative pain treatment.

METHODS

62 patients with upper abdominal surgery took part in this randomised prospective study which was approved by the local ethics committee. Epidural catheters were inserted at T 8/9 (group PCEA). General anaesthesia was performed with propofol, sufentanil 2 micrograms/kg, pancuronium, enflurane and O2:N2O = 1:2. Postoperative analgesia consisted of epidural bupivacaine 0.25% + sufentanil 2 micrograms/ml (BS). (bolus 0.05 ml/kg, lockout 10 min) in group PCEA, or of intravenous morphine (bolus 2 mg. lockout 10 min) in group PCA. The following parameters were recorded until the evening of postoperative day 4: pain intensity at rest (VASR, 1-10) and on coughing (VASH, 1-10), blood pressure, heart rate, blood gas analysis, ability to ambulate, pruritus, nausea/vomiting (PONV), patient satisfaction (0-4), time and expenses for postoperative pain treatment.

RESULTS

Median VASR (1 vs 2) and VASH (3 vs 4.5) were lower, cough intensity (2 vs 1) and patient satisfaction score (4 vs 3) were higher in PCEA compared to PCA. Ability to ambulate, pruritus, PONV, haemodynamics, paO2 and paCO2 were comparable. Postoperative pain treatment with PCEA was more time-consuming (407 vs 299 min) and expensive (71 vs 40 S/day) than PCA.

CONCLUSION

PCEA in comparison to PCA after major abdominal surgery provides superior analgesia with comparable side effects at approximately 80% higher costs.

Reduced postoperative analgesic demand after inhaled anesthesia in comparison to combined epidural-inhaled anesthesia in patients undergoing abdominal surgery

We studied the effect of epidural/general combination anesthesia, in comparison to inhaled anesthesia, on postoperative pain and analgesic consumption in patients undergoing upper abdominal surgery. Anesthesia was induced with propofol and maintained with enflurane in 70% N2O as necessary to maintain arterial blood pressure within 20% of baseline. Group I received bupivacaine 0.25% 0.2 mL/kg and sufentanil 1 microgram/kg 65 +/- 3 min before dermal incision and 0.1 mL/kg bupivacaine 0.25% + sufentanil 2 micrograms/mL (BS) every hour thereafter. Group II received 0.2 mL/kg of BS 316 +/- 15 min after dermal incision in the recovery room. Postoperative patient-controlled epidural analgesia (PCEA) with BS was provided. Pain intensities and consumption of PCEA BS were recorded on postoperative days (PODs) 1 to 5. Inspiratory fraction of enflurane was lower (0.5% +/- 0.01% vs 1.6% +/- 0.04%; P < 0.001) in Group I compared with Group II. Cumulative postoperative consumption of PCEA BS was higher in Group I compared with Group II from the evening of POD 2 until the end of the study (301 +/- 19 mL vs 249 +/- 17 mL; P < 0.001), while pain intensities were comparable at all times. The intraoperative effects of combined BS and enflurane/N2O (inspiratory fraction [Fi] approximately 1 minimum alveolar anesthetic concentration [MAC]) did not preempt postoperative pain in contrast to enflurane/N2O anesthesia (Fi approximately 2.8 MAC).

[Epidurography: comparison with CT, spiral CT and MR epidurography]

PURPOSE

The purpose of this study was to explain the origin of image patterns demonstrated by conventional epidurography, which is a controversially discussed topic in recent literature.

MATERIAL AND METHODS

After introduction of thoracic epidural catheters and iopamidol injection, conventional epidurography and CT-epidurography were performed on 25 preoperative patients. After injection of Gadolinium-DTPA MR-epidurography was performed in two patients treated for chronic pain with already introduced epidural catheters. Three volunteers also underwent identical imaging after introduction of thoracic epidural catheters and in addition helical-CT epidurography using twin-beam technology.

RESULTS

40% of the patients demonstrated the railroad track phenomenon. We were able to prove that it is a sign of a rhythmically variable filling of segments of the lateral epidural space with contrast medium 76% of the patients demonstrated no ventral epidural space at the thoracic level. 56% of the patients showed a medial area of translucence combined with a band-shaped contrasting of the epidural space in the standard ap view. This was proven in all cases to be a plica mediana dorsalis by CT. In all volunteers who underwent helical-CT and MR epidurography we observed the railroad track phenomenon and the filling defect of the anterior thoracic epidural space.

CONCLUSION

CT epidurography is well suited for obtaining new insights into the interpretation of findings obtained by conventional epidurography.

Perioperative endotoxemia and bacterial translocation during major abdominal surgery: evidence for the protective effect of endogenous prostacyclin?

OBJECTIVE

To investigate the potential role of endogenous prostacyclin (PGI2) released after mesenteric traction during major abdominal surgery on perioperative endotoxemia and bacterial translocation.

DESIGN

Prospective, randomized, double-blind clinical study.

SETTING

Operating room and surgical intensive care unit in a university hospital.

PATIENTS

Fifty consecutive patients scheduled for major abdominal surgery (pancreas resection, abdominal aortic surgery).

INTERVENTIONS

Fifteen minutes before skin incision, either 400 mg of ibuprofen or a placebo equivalent were administered intravenously. Immediately after peritoneal incision, eventration and action of the small bowel was intentionally performed in a uniform fashion.

MEASUREMENTS AND MAIN RESULTS

Baseline values were obtained before induction of anesthesia. Additional measurements, along with assessments of hemodynamics and gas exchange, were performed before incision of the peritoneum and at 5, 30, and 45 mins and 3, 6, and 24 hrs after mesenteric traction. Arterial plasma concentrations of 6-keto-prostaglandin F1 alpha and thromboxane B2 (stable metabolites of PGI2 and thromboxane A2) were determined by radioimmunoassay. Endotoxin was measured by limulus amebocyte lysate test. Mesenteric lymph nodes were sampled in 31 patients (ibuprofen n = 14, placebo n = 17) and sent for culture under sterile conditions. Transient hypotension and a marked increase of plasma 6-keto-prostaglandin F1 alpha concentrations occurred up to 6 hrs after mesenteric traction in untreated patients with median peak concentrations (2243 vs. 72 ng/L [p < .0001, placebo vs. ibuprofen], observed 5 mins after mesenteric traction). Endotoxemia occurred in both study groups. However, after mesenteric traction, plasma endotoxin concentrations were significantly higher in the ibuprofen group. Median peak concentrations (0.12 vs. 0.27 EU/mL [p < .001, placebo vs. ibuprofen]) were observed 3 hrs after mesenteric traction. Gram-negative bacteria in mesenteric lymph nodes were detected exclusively in the ibuprofen group (n = 5, p < .01).

CONCLUSIONS

In ibuprofen-pretreated patients, significantly higher endotoxin concentrations as well as bacterial translocation to mesenteric lymph nodes occurred, despite the absence of a transient decrease in mean arterial pressure that had been associated with PGI2 release. Therefore, we hypothesized that during major abdominal surgery, endogenous PGI2 released in response to mesenteric traction may play a crucial role in maintaining splanchnic microcirculation and thus preserving gut mucosal barrier function.

[Differential indications of non-opioid drugs for postoperative analgesia II. Quantification of the analgesic effect of a combination of metamizol plus diclofenac via patient-controlled analgesia]

OBJECTIVE

In a previous study we investigated the analgesic efficacy of metamizol. After laparoscopic operations, in particular, the reduction of postoperative opioid requirements within the first 24 h after surgery attained clinical relevance (-67%). In the present study we investigated the analgesic efficacy of supplementary diclofenac.

METHODS

86 patients, scheduled for minor orthopaedic surgery, laparoscopic cholecystectomy or resection of the thyroid gland, participated in a doubleblind, randomised, placebo-controlled study. The setting was comparable to our previous study, apart from the supplementary administration of diclofenac. Before induction of anaesthesia, verum-treated patients received a diclofenac suppository (100 mg), in addition to metamizol (1 g/100 ml NaCl 0.9% intravenous over 15 min). These infusions were repeated at 6h and 12h. In addition to the third infusion, the patients received a further diclofenac suppository (100 mg). Cumulated doses of buprenorphine (PCA, patient-controlled analgesia), pain scores (0-10), blood pressure, pulse and side effects were recorded during the first 6 h and again at 24 h.

RESULTS

All verum-treated patients had significantly less pain immediately after surgery and required lower cumulated doses of buprenorphine during the first 24 h after operation (laparoscopic cholecystectomy -33%, minor orthopaedic surgery -73%, resection of thyroid gland -60%).

CONCLUSIONS

Combination of metamizol and diclofenac cause a clinically relevant reduction in opioid requirements, in particular after minor orthopaedic surgery and resection of the thyroid gland. There is no need for supplementary diclofenac following laparoscopic surgery.

Prophylactic use of epidural mepivacaine/morphine, systemic diclofenac, and metamizole reduces postoperative morphine consumption after major abdominal surgery

BACKGROUND

Surgical trauma induces nociceptive sensitization leading to amplification and prolongation of postoperative pain. While preemptive analgesic treatment with numerous agents has been successful in experimental animals, results of human studies remain conflicting. The authors used a multimodal approach for preemptive analgesia before abdominal surgery: diclofenac and metamizole inhibit prostaglandin synthesis, thus influencing peripheral sensitization; epidural local anesthetics induce conduction block, epidural opioids inhibit nociceptive synaptic transmission, and metamizole induces descending inhibition. The interaction of these drugs might suppress spinal nociceptive sensitization and postoperative analgesic demand.

METHODS

One hundred forty-two patients scheduled for major abdominal surgery were randomly assigned to one of three groups and studied prospectively. Epidural catheters in groups 1 and 2 were placed at interspaces T8-T10, the position of the catheter was confirmed by epidurography, and sensory testing after administration of 5 ml mepivacaine 1%. Group 1 received 75 mg intramuscular diclofenac, 1000 mg intravenous metamizole, 5.3 +/- 1 mg epidural morphine, and 15-20 ml mepivacaine 1% 85 +/- 41 min before skin incision. Epidural analgesia was maintained by injections of 0.1 ml.kg-1.h-1 mepivacaine 1%. Group 2 patients received the balanced analgesia regimen before wound closure (221 +/- 86 min after skin incision). Group 3 patients did not receive any study substances. General anesthesia was induced with 5 mg/kg thiopental and 2 micrograms/kg fentanyl and maintained with enflurane and nitrous oxide. Postoperative analgesia consisted of patient-controlled intravenous morphine over 5 days.

RESULTS

Median visual analog scale pain intensities were < 3 cm and did not differ among the groups. Morphine consumption per hour on postoperative day 2 was 0.8 +/- 0.1 mg/h (group 1) < 1.2 +/- 0.1 mg/h (group 2) = 1.1 +/- 0.1 mg/h (group 3) and cumulative morphine consumption (in mg) on the morning of day 5 was 95 +/- 9 (group 1) < 111 +/- 11 (group 2) < 137 +/- 10 (group 3).

CONCLUSIONS

A significant reduction of patient controlled analgesia requirements could be achieved by our preincisional balanced analgesia regimen compared to application before wound closure. The more distinct difference between patients receiving balanced analgesia and those in the control group is based on the analgesic action of the study substances, which lasted about 14 h.

[Epidural and intrathecal administration of alpha 2-adreno-ceptor agonists for postoperative pain relief]

Spinal clonidine interacts with pre- and postsynaptic alpha(2)-adrenoceptors on afferent neurons in the superficial dorsal horn of the spinal cord: it causes analgesia by inhibition of the synaptic and electrotonic neurotransmission of nociceptive impulses. Epidural doses higher than 4 microg/kg have an analgesic onset time of less than 30 min, reduce pain by more than 70 %; these effects last for 4-5 h. Epidural clonidine analgesia is accompanied by a reduction in heart rate, cardiac output and blood pressure of approximately 20 % compared with baseline. The haemodynamic side effects mean close supervision is needed during the first hour after epidural application and limit the use of epidural clonidine to patients who are refractory to the analgesic effects of epidural opioid or local anaesthetics. In these patients excellent results can be achieved either with clonidine alone or with a combination of clonidine and an opioid or a local anaesthetic to exploit the additive or supra-additive interactions of these drugs.

[Differential administration of non-opioids in postoperative analgesia, I. Quantification of the analgesic effect of metamizole using patient-controlled analgesia]

OBJECTIVE

The aim of this study was to investigate: 1. Whether the perioperative administration of metamizol causes a significant reduction in postoperative opioid requirements within the first 24 h after surgery. 2. The opioid-sparing effect after different types of operations. 3. Whether preoperative application of metamizol causes a significant reduction of the pain-score immediately after operation.

METHODS

In a double-blind, randomised, placebo-controlled study, 117 patients, scheduled for minor orthopaedic or laparoscopic surgery or other operations (mainly resection of the thyroid gland and inguinal herniotomies) received either metamizol (1 g/100 ml NaCl 0.9%) or placebo (100 ml NaCl 0.9%) intravenously over 15 min in three separate doses: the first dose was given just before induction and the others 6 h and 12 h later. After surgery all patients were allowed to self-administer buprenorphine from a PCA (patient-controlled analgesia) pump (Bolus: 30 microgram, lockout: 5 min in the recovery room, 30 min on the ward). Every hour for the first 6 h and after 24 h, cumulated doses of buprenorphine, pain scores (0-10), blood pressure, pulse and side effects were recorded.

RESULTS

After minor orthopaedic and laparoscopic surgery, metamizol-treated patients had significantly less pain immediately after surgery and used a significantly lower cumulated dose of opioid in the first 24 h after surgery (-20% and -67% respectively) than patients receiving placebo. After the other types of surgery no analgesic effect could be established.

CONCLUSIONS

Perioperative administration of metamizol results in better pain relief and significantly lower buprenorphine requirements particularly after laparoscopic operations. To achieve a significant pain reduction immediately after the operation, the first dose should be applied before induction.

[Clinical randomized controlled studies in anesthesiology according to quality guidelines of good clinical practice. 2: Principles of implementation, analysis, publication and evaluation]

This article was written to give researchers and clinicians a short synopsis of ethical and thorough design, conduct, analysis, publication, and interpretation of randomised controlled clinical trials according to the European quality standards of Good Clinical Practice (GCP). The paper consists of two parts. In the first part we introduce important elements of study design, especially study hypothesis, criteria of inclusion and study population, sample size calculation, validity considerations, bias and confounding, randomisation, stratification, and masking of treatment assignment. Different treatment allocation like multiple parallel groups, factorial experiment, cross-over, and sequential design are presented. Requirements of ethical standards according to the Declaration of Helsinki are discussed for their necessity in any experimentation in humans. Principles of informed consent are demonstrated with emphasis on special conditions in anaesthesia, emergency medicine, and intensive care research. In the second part of this article we explain issues of baseline assessment, experimental intervention, data recording, and data monitoring, particularly of negative or hazardous treatment effects. Topics of data analysis and reporting of trial results in publications are illustrated with regard to their influence on subsequent interpretation.

Analgesic and hemodynamic effects of epidural clonidine, clonidine/morphine, and morphine after pancreatic surgery--a double-blind study

This study characterizes analgesia an hemodynamics after epidural clonidine 8 micrograms/kg (Group C) or clonidine 4 micrograms/kg+morphine 2 mg (Group CM) in comparison to epidural morphine 50 micrograms/kg (Group M). Forty-five patients scheduled for pancreatectomy in combined general/epidural anesthesia were studied. The study drugs were administered 75 min postoperatively and for 10 h pain intensity (visual analog scale [VAS]), heart rate (HR), mean arterial pressure (MAP), and cardiac output (CO) were measured; filling pressures were kept > 5 mm Hg. Adequate analgesia could be achieved within 1 h in all patients of Groups C and CM, but only in six patients of Group M (P < 0.001). Quality of analgesia was comparable in all groups (VAS reduction 82% +/- 20%, mean +/- SD) but duration of analgesic action was longer in Groups CM (586 +/- 217 min) and M (775 +/- 378 min) compared to Group C (336 +/- 119 min) (P < 0.001). In Group M, no hemodynamic alterations occurred. In Groups C and CM, HR, CO, and MAP were reduced significantly compared to baseline within the first 15-90 min, while stroke volume and systemic vascular resistance remained stable. We conclude, that hemodynamic alteration after epidural clonidine under conditions of stable filling pressures is caused mainly by a decrease in HR. It is not an effect of analgesia but of the intrinsic antihypertensive action of clonidine.

[Clinical randomized controlled studies in anesthesiology according to the quality guidelines of good clinical practice. 1: Basic trial design]

This article was written to give researchers and clinicians a short synopsis of ethical and thorough design, conduct, analysis, publication, and interpretation of randomised controlled clinical trials according to the European quality standards of Good Clinical Practice (GCP). The paper consists of two parts. In the first part we introduce important elements of study design, especially study hypothesis, criteria of inclusion and study population, sample size calculation, validity considerations, bias and confounding, randomisation, stratification, and masking of treatment assignment. Different treatment allocation like multiple parallel groups, factorial experiment, cross-over, and sequential design are presented. Requirements of ethical standards according to the Declaration of Helsinki are discussed for their necessity in any experimentation in humans. Principles of informed consent are demonstrated with emphasis on special conditions in anaesthesia, emergency medicine, and intensive care research. In the second part of this article we explain issues of baseline assessment, experimental intervention, data recording, and data monitoring, particularly of negative or hazardous treatment effects. Topics of data analysis and reporting of trial results in publications are illustrated with regard to their influence on subsequent interpretation.

[Analgesia with intra-articular morphine following knee joint arthroscopy? A double-blind, randomized study with patient-controlled analgesia]

Previous studies investigating the peripheral action of locally instilled morphine after arthroscopic knee surgery found evidence for an analgesic effect. Follow-up studies have lead to conflicting results. We used patient-controlled analgesia (PCA) to test the analgesic potency of intraarticular morphine. METHODS. Patients undergoing arthroscopic knee surgery under general anaesthesia received, after written informed consent and in double-blind and randomised manner, 1 mg morphine diluted in 10 ml saline either intraarticularly or intravenously at the end of the surgical procedure. A control injection of 10 ml saline was given at the other site. The pain intensity on a visual analogue scale (VAS) and the cumulative morphine consumption were recorded at 1, 2, 3, 4, 6, 8 and 24 h after the end of general anaesthesia.

STATISTICS

Wilcoxon rank sum test with P < 0.05. RESULTS. A total of 59 patients were included in the study; 29 received morphine intraarticularly (verum group), 30 intravenously (control group). There was no difference in gender, age, duration of arthroscopy or anaesthesia. There were more than 60% diagnostic arthroscopies in both groups; other types of surgery were comparable, with the exception of cruciate band repair procedures only in the control group. We found no difference in morphine consumption or pain intensity between the two groups throughout the study period. Median overall consumption of morphine after 24 h was 14 mg in the verum group and 15 mg in the control group, with wide interindividual variation. Pain intensities were remarkably low. The peak pain intensity of both groups was found at 1 h postoperatively, with median 16/100 on the VAS in both groups. Blinding was robust. CONCLUSION. We found no reduction in postoperative morphine supplementation after 1 mg morphine intraarticularly compared to 1 mg intravenously given at the end of knee arthroscopies. There were also no differences in pain intensities on a VAS. We conclude that titration of postoperative pain with a morphine-filled PCA pump was unable to show a difference in analgesic potency between intraarticular and intravenous morphine.

Analgesic and hemodynamic effects of epidural clonidine, clonidine/morphine, and morphine after pancreatic surgery--a double-blind study

This study characterizes analgesia an hemodynamics after epidural clonidine 8 micrograms/kg (Group C) or clonidine 4 micrograms/kg+morphine 2 mg (Group CM) in comparison to epidural morphine 50 micrograms/kg (Group M). Forty-five patients scheduled for pancreatectomy in combined general/epidural anesthesia were studied. The study drugs were administered 75 min postoperatively and for 10 h pain intensity (visual analog scale [VAS]), heart rate (HR), mean arterial pressure (MAP), and cardiac output (CO) were measured; filling pressures were kept > 5 mm Hg. Adequate analgesia could be achieved within 1 h in all patients of Groups C and CM, but only in six patients of Group M (P < 0.001). Quality of analgesia was comparable in all groups (VAS reduction 82% +/- 20%, mean +/- SD) but duration of analgesic action was longer in Groups CM (586 +/- 217 min) and M (775 +/- 378 min) compared to Group C (336 +/- 119 min) (P < 0.001). In Group M, no hemodynamic alterations occurred. In Groups C and CM, HR, CO, and MAP were reduced significantly compared to baseline within the first 15-90 min, while stroke volume and systemic vascular resistance remained stable. We conclude, that hemodynamic alteration after epidural clonidine under conditions of stable filling pressures is caused mainly by a decrease in HR. It is not an effect of analgesia but of the intrinsic antihypertensive action of clonidine.

[CT-epidurography. A comparison of conventional and CT-epidurography with contrast medium injection through a thoracic peridural catheter]

Epidurography with contrast medium is used to verify the correct position of an epidural catheter and to detect malpositioning. There is great variability in the distribution of contrast medium according to the individual morphology of the epidural space and the way it is injected. Results of investigations of the anatomy of the spinal canal and epidural space performed with anatomic specimens, epiduroscopy, and conventional and computed tomographic (CT) epidurography are sometimes contradictory. We have performed CT epidurography in approximately 30 patients to date. Insights regarding the distribution of contrast medium in the epidural space can help to interpret conventional epidurographies and to explain special features, such as the "rail-road-track phenomenon" or the plica mediana dorsalis. METHODS. Patients scheduled for major abdominal operations were studied. Catheters were introduced into the thoracic epidural space on the day before the operation. Conventional epidurographies were performed routinely after insertion of the catheters with a mobile X-ray apparatus, usually in the recovery room, using 5 ml iopamidol (Solutrast 250 M). Selected patients (good mental state and stable psychic condition), after written consent and with approval of the local ethical committee, were investigated with CT epidurography using the same contrast medium (partly diluted). From among the CT scans performed until now, five characteristic images are presented and compared to conventional epidurographies. RESULTS. When small volumes (5 ml) of iopamidol were injected slowly, we regularly observed a railroad-track phenomenon in the AP images of conventional epidurographies. After rapid injection of larger volumes (10-15 ml), the spread was more homogeneous and sometimes outline a lighter zone of contrast distribution in the midline. CT epidurography in these cases (5 out of 30 patients) revealed a plica mediana dorsalis. In the majority of the CT scans of the thoracic epidural space its anterior (ventral) compartment was unfilled by contrast medium. According to the findings of several investigators, dura mater and ligamentum longitudinal posterius have grown together, so that an epidural space does not exist in ventral thoracic segments of the spinal canal. In lower thoracic and lumbar segments both structures are separate, and a wide anterior epidural space was present and filled with contrast medium. In other cases the dorsal and dorsolateral epidural space was completely filled, but the contrast medium stopped behind the spinal nerves and surrounding dural sheaths, as if these structures, together with the connective tissue strands between them, formed a membrane that spread in a frontal plane. A railroad-track phenomenon is interpreted in the literature as the X-ray correlate of contrast medium spread in the subdural space, indicating an incorrect catheter position. According to conventional epidurographies and confirmed by CT scans, this feature is also seen regularly in cases with correct catheter position. Small volumes of iopamidol spread preferentially into the wider parts of the epidural space between the gaps of the vertebral arcs, whereas the dura mater and periosteal layers touch at the inner side of the pedicules and laminae, allowing the existence of only a potential epidural space. This rhythmic widening and narrowing of the epidural space is the explanation of the "railroad track" in AP contrast epidurographies. CONCLUSIONS. CT epidurography is a valuable tool to provide better insight into the morphology of the epidural space when filled with fluid (contrast medium, local anaesthetics), complementing findings using epiduroscopy and anatomic specimens. It stands to reason that this time- and cost-expensive method can never replace conventional epidurographies, but can help to interpret them properly.

[Analgesia and hemodynamics under 8 mu/kg clonidine for pain therapy following major abdominal surgery]

OBJECTIVE

To characterise the haemodynamic profile after epidural injection of high-dose clonidine for postoperative pain management and to establish recommendations for the therapy of haemodynamic instabilities.

DESIGN

20 patients with major surgery on pancreas, stomach or infrarenal aorta took part in the study. Anaesthesia was a combined epidural/inhalational regimen with bupivacaine 0.25%, enflurane, oxygen/nitrous oxide, fentanyl 0.1 mg and pancuronium. Postoperative analgesia consisted of morphine 50 micrograms/kg in 10 ml NaCl 0.9% for the first 12 postoperative hours; if pain > = 5 points on the VAS occurred after > 12 h postoperatively clonidine 8 micrograms/kg in 10 ml NaCl 0.9% was injected epidurally and the pain intensity (self-assessment by the patient using the visual analog scale) and circulation (invasive pressure monitoring, pulmonary artery catheter) was monitored for 60 minutes in ten minutes intervals.

RESULTS

The reduction of the initial VAS score of 6 was 50% after 20 minutes and 100% after 60 minutes. We observed a significant decline in heart rate (87 +/- 11 (t0), 74 +/- 10 min-1 (t60)), mean arterial pressure (97 +/- 17 (t0), 72 +/- 15 mmHg (t60)) and cardiac output (8.7 +/- 1.3 (t0), 7.0 +/- 1.3 l.min-1 (t60)) (all p < 0.001) and no change of systemic vascular resistance. Filling pressures (CVP and PCWP) remained stable. In 9 patients the mean arterial pressure fell below 60 mmHg (always within the first 40 min); 6 of these patients responded to infusion of a colloid (500 ml of hydroxyethyl starch at > = 2 ml/kg.min) whereas the other 3 patients needed a bolus injection of a betamimetic catecholamine (theodrenaline/cafedrine, Akrinor).

CONCLUSION

Epidural clonidine 8 micrograms/kg causes rapid and intense analgesia. Haemodynamic instability is a consequence of a drop in heart rate and has to be treated accordingly. The application of a pure vasopressor does not seem to be indicated taking in account the fact that the total peripheral resistance remains unchanged and in the normal range.

[The effect of thoracic epidural anesthesia on the pathophysiology of the eventration syndrome]

Abdominal mesenteric traction (MT) results in decreased mean arterial pressure (MAP), systemic vascular resistance (SVR) and increased cardiac output (CO). This response is induced by a considerable release of prostacyclin (PGI2). Precipitous falls in systemic arterial pressure related to central and/or autonomic nervous reflex arcs also have been described during operations on the upper abdominal viscera. Those hypotensive responses to visceral traction appear to be transmitted along afferent fibres contained within the splanchnic nerves. We investigated the influence of supplementary thoracic epidural anaesthesia on mesenteric traction response during major abdominal surgery. METHODS. With the approval of the Human Investigation Review Board we studied 40 patients scheduled for major abdominal surgery (infrarenal aortic, gastrointestinal and pancreatic surgery) according to a prospective, randomized double-blinded protocol. Patients were randomized to two different anaesthetic regimens. Patients in group 1 received general anaesthesia (GA n = 20) with 0.1-0.15 mg/kg midazolam and 10 micrograms/kg fentanyl prior to skin incision. Maintenance included 65% nitric oxide in oxygen and 0.1 mg increments of fentanyl as required. Group 2 patients (EA n = 20) underwent a combined technique of dose-reduced general anaesthesia and supplementary continuous, thoracic epidural anaesthesia (bupivacaine 0.25%, sensory blockade T4 to L1-3). In both anaesthesia groups ibuprofen (400 mg i.v.) or a placebo equivalent was administered 15 min before the induction of anaesthesia. MT was applied in a uniform fashion. Baseline values preceded the incision of the peritoneum. Further assessments followed 5, 15 and 30 min after MT. The plasma concentrations of 6-keto-PGF1 alpha (stable metabolite of PGI2), TXB2 (stable metabolite of thromboxane), PGF2 alpha, KH2-PGF2 alpha (stable metabolite of PGF2 alpha) were determined by radioimmunoassay. At all assessments we recorded systolic and diastolic blood pressure, heart rate and measured arterial blood gases. Statistical analyses were performed using three-factor ANOVA for repeated measurements after log(x) transformation. A P-value of less than 0.05 was considered significant when the Bonferroni-Holm adjustment was applied. RESULTS. Patients with supplementary epidural anaesthesia demonstrated lower systolic (P = 0.0001) and diastolic (P = 0.006) blood pressure than those in the GA group. Nevertheless, in untreated patients in the EA and GA group there was a significant decrease of about 20-30% in systolic and diastolic blood pressure (P = 0.0001) after mesenteric traction. Irrespective of the anaesthetic procedure, paO2 (P = 0.0001) decreased after mesenteric traction in the placebo group. The control patients in the GA group exhibited a more pronounced increase in heart rate after MT. After traction on the mesentery a significant 20- to 30-fold increase in 6-keto-PGF1 alpha plasma concentrations occurred in the placebo group: GA group 1950/58 (5 min), 1574/59 (15 min) 858/66 (30 min) ng/l, P < 0.0001; EA group: 2002/106 (5 min), 2955/107 (15 min) 1807/70 (30 min) ng/l, P < 0.0001, for placebo vs ibuprofen. There was no statistically significant difference between the two anaesthetic procedures used. In ibuprofen-pretreated patients haemodynamics and paO2 values were stable, while 6-keto-PGF1 alpha plasma concentrations remained within the normal range. CONCLUSION. Our data clearly indicate that the mesenteric traction response consists in relevant haemodynamic alterations and a significant decrease of paO2. Stable haemodynamics and paO2 following cyclooxygenase inhibition signify an action mediated by prostacyclin. Deafferentation of the splanchnic nerves by supplementary thoracic epidural anaesthesia did not influence either prostacyclin release or the decrease in blood pressure and paO2 after traction on the mesentery root...

[No better vigilance after general anesthesia with propofol in colonic surgery. A comparison of three procedures for general anesthesia (propofol, halothane and midazolam/fentanyl) in combination with catheter epidural anesthesia]

Early mental and psychomotor recovery was studied in 67 patients undergoing colorectal surgery under continuous epidural anaesthesia and light general anaesthesia using propofol, halothane, and midazolam/fentanyl. The study was approved by the local ethics committee. All patients received epidural anaesthesia with 0.25% bupivacaine and were then randomly allocated to one of three groups. In group I (halothane), light general anaesthesia was induced with thiopental 3-5 mg/kg and maintained with halothane. The propofol group (II) received 2 mg/kg for induction and a mean continuous infusion of 1.7 mg/kg.h. In group III (Mi/Fe), midazolam and fentanyl were used for induction and maintenance. All patients were intubated, received non-depolarising muscle relaxants, and were manually ventilated with nitrous oxide-oxygen (2:1.2). For postoperative analgesia, 0.05 mg/kg morphine was administrated epidurally 30 min before the end of the operation; 30, 60, 90, and 120 min after arriving in the recovery room, vigilance was assessed using a modified Steward score, the Trieger test, the ability to recall a column of numbers (KAI test), and symbol counting (CI test). Heart rate, blood pressure, arterial oxygen saturation, and blood gases were recorded. RESULTS. The three groups were comparable with regard to age, sex, ASA classification, and duration of anaesthesia and operation (Table 3). There was no difference between the groups in performance of the recovery tests (Figs. 2-5), blood pressure, heart rate, arterial blood gas analysis (Fig. 6), or oxygen saturation. Comparing pre- and postoperative values, we found severe psychomotor and mental impairment in all groups. pCO2 was slightly elevated in all groups, but only 3 patients in the propofol group and 6 in the midazolam/fentanyl group developed hypercapnia above 50 mm Hg. Patients receiving propofol or midazolam/fentanyl had significantly less postoperative nausea and vomiting than those receiving halothane (Table 5). CONCLUSION. It is concluded that propofol offers no advantage over halothane or midazolam/fentanyl where early postoperative recovery is concerned. Intraoperatively, all three techniques provided good anaesthesia. Propofol and midazolam/fentanyl caused less postoperative nausea and vomiting than halothane anaesthesia.

The effect of ephedrine bolus administration on left ventricular loading and systolic performance during high thoracic epidural anesthesia combined with general anesthesia

We investigated the effect of ephedrine on left ventricular function in patients without cardiovascular disease under high thoracic epidural anesthesia combined with general anesthesia. Because the epidural block was extended to all cardiac segments, ephedrine was assumed to be deprived of its centrally mediated actions. Left ventricular (LV) function was assessed using transesophageal echocardiography. We measured arterial pressure (AP), heart rate (HR), LV end-systolic and end-diastolic diameter and area (ESA, EDA), wall thickness, and LV ejection time before and after intravenous ephedrine bolus administration. We calculated area ejection fraction (EFA), end-systolic wall stress (ESWS), and mean velocity of circumferential fiber shortening (mVcfc). Ephedrine had a biphasic effect on left ventricular function. It transiently decreased EDA from 18.9 to 16.5 cm2 (mean), whereas EFA and mVcfc were increased from 33% to 49%, and from 1.88 to 2.67 circumferences/s, respectively. During the second phase, ephedrine increased mean arterial pressure (MAP) from a baseline value of 62 to 87 mm Hg, EDA was restored to 19.3 cm2, and EFA and mVcfc remained above baseline (52% and 2.64 circumferences/s, respectively). ESWS was not significantly increased from baseline. We conclude that ephedrine improves left ventricular contractility, even in the presence of high thoracic epidural anesthesia, without causing relevant changes of left ventricular afterload.

Effect of phenylephrine bolus administration on left ventricular function during high thoracic and lumbar epidural anesthesia combined with general anesthesia

The effect of phenylephrine (PHE) boluses on left ventricular (LV) function was examined in patients without cardiovascular disease who developed arterial hypotension during high thoracic epidural anesthesia (TEA) combined with general anesthesia (GA) (group 1) or lumbar epidural anesthesia (LEA) combined with GA (group 2). LV function was assessed by transesophageal echocardiography (TEE) before and after central venous injection of 1 microgram/kg PHE. Fractional diameter shortening (FDS), end-systolic wall stress (ESWS), and rate-corrected velocity of circumferential fiber shortening (mVcfc) were determined. PHE effectively restored arterial blood pressure in both groups with a peak effect between 30 and 45 s after injection. FDS was reduced from 38% to 25% (mean, P < 0.01) in group 1 and remained unchanged in group 2. ESWS increased from 70 to 143 x 10(3) dyne.cm-2 (P < 0.01) and from 57 to 86 x 10(3) dyne.cm-2 (P < 0.05), in groups 1 and 2, respectively. mVcfc was significantly reduced from 1.11 to 0.80 circ/s (P < 0.05) in group 1 and was not altered in group 2. The authors conclude that PHE given as an intravenous bolus to patients under high TEA plus general anesthesia causes a transient impairment of LV function.