Heparin-Coated Left Heart Bypass: Renal Function and Hormonal Response

The effect of partial (50 mI/min/kg) left heart bypass (LHBP) on renal function, plasma renin activity (PRA), aldosterone, arginine vasopressin and atrial natriuretic peptide (ANP) response was studied in ten anesthetized, open-chested mongrel dogs (weight 23-50 kg) over a period of 6 h. Standard equipment with systemic heparinization (control), initially 300 IU/kg, was employed in five dogs, and heparin-coated equipment without additional heparin in the other five (heparin coated). Urine was continuously collected through a transurethral catheter. Urine samples and pulmonary artery blood samples for hormonal assays were taken at preset intervals before and during LHBP. The results in each group were summarized as median (25th-75th) and compared using the Mann-Whitney U test. In the control group higher blood loss required higher volume substitution. Urine output was maintained in heparin coated and slightly decreased at 3-4 h in control LHBP. Creatinine clearance at 3-5 h and free-water clearance at 3-6 h were significantly higher with heparin-coated LHBP. PRA, aldosterone and vasopressin peaked at 1-2 h of LHBP similarly in both groups, not exceeding the values before perfusion. PRA and aldosterone response was sustained during 6 h and the percentage changes corrected for hemodilution indicated a stronger response with standard equipment. Vasopressin concentrations were slightly but significantly higher in the control group at 1 and 6 h of perfusion. Corrected for hemodilution, vasopressin percentage changes were not different in the two groups. ANP, despite atrial unloading, rose similarly in both groups. There was a tendency to poorly sustained ANP response (control > heparin-coated) after 6 h of perfusion. In conclusion, preserved renal function and attenuated hormonal response during canine partial LHBP are results of better hemostasis and circulatory integrity of perfusion without systemic heparinization.

Guidelines for sedation and/or analgesia by non-anaesthesiology doctors

The still ever increasing demand for sedation and/or analgesia for diagnostic and therapeutic procedures puts high pressure on anaesthesia care providers all over Europe. Since the capacity to provide that service by anaesthetists is limited in most European countries, guidelines for non-anaesthetist doctors who want to sedate patients on a high-quality level and especially in a safe way are mandatory. This paper, produced by a working party of the European Board of Anaesthesiology of the European Union of Medical Specialists (EUMS/UEMS), gives direction to those practitioners who feel responsibilities in this area of medicine. Close cooperation with anaesthesiologists seems mandatory to achieve and sustain a high-quality standard for our patients undergoing medical or surgical procedures under sedation.

Anaesthesia for lung volume reduction surgery

To date, only a few published studies have been concerned with the anaesthesiological aspects of lung volume reduction surgery. This review summarizes the different anaesthetic concepts and offers a general strategy to meet specific requirements. Limitation of peak inspiratory pressure, tolerance of hypercapnia and avoidance of hypoxia during one-lung ventilation, and the immediate postoperative tracheal extubation of these patients, are considered to be crucial. However, many aspects of the procedure and of anaesthesiological management remain to be elucidated.

State-of-the-art blood saving techniques

Preoperative autologous donation, the use of erythropoietin, acute normovolaemic haemodilution, acceptance of minimal perioperative haemoglobin levels, the use of specific drugs (aprotinin, antifibrinolytics), cell saving and a meticulous surgical technique aimed at minimizing blood loss have all been described as blood saving techniques. Each has proved effective in reducing the need for allogeneic blood transfusions. With an appropriate selection of patients, all techniques can be used efficiently.

Hypoxia aggravates lipopolysaccharide-induced lung injury

The animal model of inflammatory response induced by intratracheal application of lipopolysaccharide includes many typical features of acute lung injury or the acute respiratory distress syndrome. A number of experimental investigations have been performed to characterize the nature of this injury more effectively. In inflammatory conditions, hypoxia occurs frequently before and in parallel with pulmonary and non-pulmonary pathological events. This current study was designed to examine the in vivo effect of hypoxia as a potentially aggravating condition in endotoxin-induced lung injury. Lipopolysaccharide, 150 microg, was instilled intratracheally into rat lungs, and thereafter animals were exposed to either normoxia or hypoxia (10% oxygen). Lungs were collected 2, 4, 6 and 8 h later. Inflammatory response and tissue damage were evaluated by quantitative analysis of inflammatory cells and mediators, surfactant protein and vascular permeability. A significantly enhanced neutrophil recruitment was seen in lipopolysaccharide-animals exposed to hypoxia compared to lipopolysaccharide-animals under normoxia. This increased neutrophil accumulation was triggered by inflammatory mediators such as tumour necrosis factor-alpha and macrophage inflammatory protein-1beta, secreted by alveolar macrophages. Determination of vascular permeability and surfactant protein-B showed enhanced concentrations in lipopolysaccharide-lungs exposed to hypoxia, which was absent in animals previously alveolar macrophage-depleted. This study demonstrates that hypoxia aggravates lipopolysaccharide injury and therefore represents a second hit injury. The additional hypoxia-induced inflammatory reaction seems to be predominantly localized in the respiratory compartment, underlining the compartmentalized nature of the inflammatory response.

Anaesthetic preconditioning but not postconditioning prevents early activation of the deleterious cardiac remodelling programme: evidence of opposing genomic responses in cardioprotection by pre- and postconditioning # #This article is accompanied by Editorial I

BACKGROUND

Anaesthetic preconditioning (A_PreC) and postconditioning (A_PostC) both provide protection against ischaemia-reperfusion in the heart. However, post-ischaemic gene responses may differ between the two therapeutic strategies.

METHODS

Isolated perfused rat hearts were exposed to 40 min test ischaemia followed by 3 h reperfusion and used to determine transcriptional changes in response to A_PreC and A_PostC. A_PreC was induced by 15 min of isoflurane 2.1 vol% followed by 10 min of washout, and A_PostC was induced by 15 min of isoflurane 2.1 vol% administered at the onset of reperfusion. Untreated hearts served as ischaemic control (ISCH). Coupled-two way clustering (CTWC) and principal component analysis (PCA) were used to identify gene expression patterns.

RESULTS

A_PreC (7[sd 1]%) and A_PostC (6[2]%) produced a similar decrease in infarct size (ISCH 36[1]%, P<0.05). However, post-ischaemic genomic reprogramming was completely different. Few genes were jointly regulated (2.1 per thousand of upregulated genes and 1.3% of downregulated genes). Eight stable gene clusters including three subclusters emerged from CTWC and were related to inflammation, signalling, ion channels, transcription factors, long interspersed repetitive DNA, heat shock response and remodelling. Two stable sample clusters were identified for postconditioned hearts (first cluster) and for all other protocols (second cluster), emphasizing the unique cardiac phenotype elicited by A_PostC. PCA revealed a close genomic relationship between A_PreC and non-ischaemic healthy myocardium.

CONCLUSIONS

A_PreC, but not A_PostC, induces a post-ischaemic gene expression profile similar to virgin myocardium and prevents activation of the deleterious cardiac remodelling programme. Hence A_PreC and A_PostC are not interchangeable with respect to their molecular outcome in the heart.

[Strategies for perioperative sympatho-modulation]

Despite the growing evidence for the efficacy of different sympatho-modulatory therapies to lower perioperative cardiac morbidity and mortality, such therapeutic strategies are rather infrequently used in daily clinical practice. Most physicians involved in perioperative medicine are aware of the increasing literature related to this topic, but only few comply with current clinical practice guidelines even in the absence of contraindications. This review discusses possible explanations for this reluctance and again summarizes the basic and clinical principles of current sympatho-modulatory therapies including alpha(2)-agonism, beta-adrenergic antagonism, and regional anesthetic techniques in modern anesthetic practice. In addition, the emerging perioperative concept of a patient-tailored individualized pharmacotherapy based on "gene profiling", particularly the adrenergic polymorphisms, is discussed.

Complaints of sore throat after tracheal intubation

BACKGROUND AND OBJECTIVE

Sore throat and hoarseness rank, besides pain and nausea, among the most frequent subjective complaints after tracheal intubation for general anaesthesia. Our intention was to determine the incidence of postoperative sore throat from a large sample of patients and thus to identify the most important associated factors.

METHODS

We prospectively followed up 809 adult patients who underwent elective surgical interventions and examined their history, the applied anaesthetic techniques, perioperative course and the occurrence, intensity and duration of postoperative throat complaints. The assignment and professional experience of the involved intubators were also assessed. The influence of a multitude of variables on postoperative throat complaints was statistically analysed.

RESULTS

Postoperative sore throat was present in 40% overall being significantly higher in female than in male (44% vs. 33%; P = 0.001). The mean pain intensity in the affected patients (n = 323) was 28+/-12 mm on a visual analogue scale where 0 = no pain and 100 = extreme pain. The average duration was 16+/-11 h. Main factors associated with throat complaints were female sex; history of smoking or lung disease, duration of anaesthesia, postoperative nausea, bloodstain on the endotracheal tube and natural teeth. We could find no influence on the occurrence or intensity of throat complaints by the professional assignment or the length of professional experience of the personnel involved.

CONCLUSIONS

Postoperative throat complaints frequently arise after tracheal intubation for general anaesthesia in the first 2 postoperative days, but they are of limited intensity and duration.

Preconditioning with sevoflurane decreases PECAM-1 expression and improves one-year cardiovascular outcome in coronary artery bypass graft surgery

BACKGROUND

Cardiac preconditioning is thought to be involved in the observed decreased coronary artery reocclusion rate in patients with angina preceding myocardial infarction. We prospectively examined whether preconditioning by sevoflurane would decrease late cardiac events in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

Seventy-two patients scheduled for elective CABG surgery were randomized to preconditioning by sevoflurane (10 min at 4 vol%) or placebo. For all patients, follow-up of adverse cardiac events was obtained 6 and 12 months after surgery. Transcript levels for platelet-endothelial cell adhesion molecule-1 (PECAM-1/CD31), catalase and heat shock protein 70 (Hsp70) were determined in atrial biopsies after sevoflurane preconditioning.

RESULTS

Pharmacological preconditioning by sevoflurane reduced the incidence of late cardiac events during the first year after CABG surgery (sevoflurane 3% vs 17% in the placebo group, log-rank test, P=0.038). One patient in the sevoflurane group and three patients in the placebo group experienced new episodes of congestive heart failure and three additional patients had coronary artery reocclusion. Perioperative peak concentrations for myocardial injury markers were higher in patients with subsequent late cardiac events [NTproBNP, 9031 (4125) vs 3049 (1906) ng litre(-1), P<0.001; cTnT, 1.31 (0.88) vs 0.46 (0.29) microg litre(-1), P<0.001]. Transcript levels were reduced for PECAM-1 and increased for catalase but unchanged for Hsp70 in atrial biopsies after sevoflurane preconditioning.

CONCLUSIONS

This prospective randomized clinical study provides evidence of a protective role for pharmacological preconditioning by sevoflurane in late cardiac events in CABG patients, which may be related to favourable transcriptional changes in pro- and antiprotective proteins.

The airway compartment: chambers of secrets

The adhesion molecule intercellular adhesion molecule-1 (ICAM-1) is known to play a crucial role in lung inflammation such as endotoxin-induced injury. Although ICAM-1 has been characterized on endothelial cells, limited information is available regarding its expression in the epithelial compartment. The present review provides novel views on this aspect.

Release of inflammatory mediators in irradiated cell salvage blood and their biological consequences in human beings following transfusion

BACKGROUND AND OBJECTIVE

Irradiation of intraoperative cell salvage blood has recently been used to inactivate tumour cells before retransfusion, during cancer surgery. No information is available about a potential inflammatory response of the recipient to the retransfusion of irradiated intraoperative cell salvage blood. This pilot study was conducted to investigate the possible release of the pro-inflammatory mediators, tumour necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), eotaxin and monocyte chemo-attractant protein-1 (MCP-1), in the serum of recipients by intraoperative retransfusion of irradiated intraoperative cell salvage blood.

METHODS

Nine patients undergoing gynaecological cancer surgery were included in this study. Intraoperative cell salvage blood was irradiated with 50 Gy and retransfused to the patient. Serum and intraoperative cell salvage blood concentrations of TNF-alpha, IL-1beta, eotaxin and MCP-1 were repeatedly analysed before and after retransfusion, respectively before and after irradiation.

RESULTS

Traces of mediators were detected in intraoperative cell salvage blood but no increase due to irradiation was observed. Following transfusion of intraoperative cell salvage blood, minute quantities (all < 30 pg mL(-1) of mediators were detected in the serum of patients. However, there was no significant upregulation compared to serum values before retransfusion.

CONCLUSIONS

These results provide evidence that retransfusion of irradiated intraoperative cell salvage blood might represent a blood-saving strategy in cancer surgery without an immunological inflammatory response as shown by a lack of upregulation of inflammatory mediators.

Effect of rofecoxib on platelet aggregation and blood loss in gynaecological and breast surgery compared with diclofenac

BACKGROUND

Non-selective cyclooxygenase (COX) inhibitors or non-steroidal anti- inflammatory drugs (NSAIDs) are frequently omitted for perioperative pain relief because of potential side-effects. COX-2-selective inhibitors may have a more favourable side-effect profile. This study tested the hypothesis that the COX-2-selective inhibitor rofecoxib has less influence on platelet function than the NSAID diclofenac in gynaecological surgery. In addition, analgesic efficacy and side-effects of the two drugs were compared.

METHODS

In this single-centre, prospective, double-blind, active controlled study, women undergoing vaginal hysterectomy (n=25) or breast surgery (n=25) under general anaesthesia received preoperatively 50 mg of rofecoxib p.o. followed 8 and 16 h later by two doses of placebo or three doses of diclofenac 50 mg p.o. at the same time points. We assessed arachidonic acid-stimulated platelet aggregation before and 4 h after the first dose of study medication, estimated intraoperative blood loss, and haemoglobin loss until the first morning after surgery. Analgesic efficacy, use of rescue analgesics, and side-effects were also recorded.

RESULTS

In the rofecoxib group, stimulated platelet aggregation was disturbed less (P=0.02), and estimated intraoperative blood loss (P=0.01) and the decrease in haemoglobin were lower (P=0.01). At similar pain ratings, the use of anti-emetic drugs was less in the rofecoxib group (P=0.03).

CONCLUSION

Besides having a smaller effect on platelet aggregation, one oral dose of rofecoxib 50 mg given before surgery provided postoperative analgesia similar to that given by three doses of diclofenac 50 mg and was associated with less use of anti-emetics and less surgical blood loss in gynaecological surgery compared with diclofenac.

Patient well-being after general anaesthesia: a prospective, randomized, controlled multi-centre trial comparing intravenous and inhalation anaesthesia

BACKGROUND

The aim of this study was to assess postoperative patient well-being after total i.v. anaesthesia compared with inhalation anaesthesia by means of validated psychometric tests.

METHODS

With ethics committee approval, 305 patients undergoing minor elective gynaecologic or orthopaedic interventions were assigned randomly to total i.v. anaesthesia using propofol or inhalation anaesthesia using sevoflurane. The primary outcome measurement was the actual mental state 90 min and 24 h after anaesthesia assessed by a blinded observer using the Adjective Mood Scale (AMS) and the State-Trait-Anxiety Inventory (STAI). Incidence of postoperative nausea and vomiting (PONV) and postoperative pain level were determined by Visual Analogue Scale (VAS) 90 min and 24 h after anaesthesia (secondary outcome measurements). Patient satisfaction was evaluated using a VAS 24 h after anaesthesia.

RESULTS

The AMS and STAI scores were significantly better 90 min after total i.v. anaesthesia compared with inhalation anaesthesia (P=0.02, P=0.05, respectively), but equal 24 h after both anaesthetic techniques (P=0.90, P=0.78, respectively); patient satisfaction was comparable (P=0.26). Postoperative pain was comparable in both groups 90 min and 24 h after anaesthesia (P=0.11, P=0.12, respectively). The incidence of postoperative nausea was reduced after total i.v. compared with inhalation anaesthesia at 90 min (7 vs 35%, P<0.001), and 24 h (33 vs 52%, P=0.001).

CONCLUSION

Total i.v. anaesthesia improves early postoperative patient well-being and reduces the incidence of PONV.

Anaesthetics and cardiac preconditioning. Part I. Signalling and cytoprotective mechanisms

Cardiac preconditioning represents the most potent and consistently reproducible method of rescuing heart tissue from undergoing irreversible ischaemic damage. Major milestones regarding the elucidation of this phenomenon have been passed in the last two decades. The signalling and amplification cascades from the preconditioning stimulus, be it ischaemic or pharmacological, to the putative end-effectors, including the mechanisms involved in cellular protection, are discussed in this review. Volatile anaesthetics and opioids effectively elicit pharmacological preconditioning. Anaesthetic-induced preconditioning and ischaemic preconditioning share many fundamental steps, including activation of G-protein-coupled receptors, multiple protein kinases and ATP-sensitive potassium channels (K(ATP) channels). Volatile anaesthetics prime the activation of the sarcolemmal and mitochondrial K(ATP) channels, the putative end-effectors of preconditioning, by stimulation of adenosine receptors and subsequent activation of protein kinase C (PKC) and by increased formation of nitric oxide and free oxygen radicals. In the case of desflurane, stimulation of alpha- and beta-adrenergic receptors may also be of importance. Similarly, opioids activate delta- and kappa-opioid receptors, and this also leads to PKC activation. Activated PKC acts as an amplifier of the preconditioning stimulus and stabilizes, by phosphorylation, the open state of the mitochondrial K(ATP) channel (the main end-effector in anaesthetic preconditioning) and the sarcolemmal K(ATP) channel. The opening of K(ATP) channels ultimately elicits cytoprotection by decreasing cytosolic and mitochondrial Ca(2+) overload.

Anaesthetics and cardiac preconditioning. Part II. Clinical implications

There is compelling evidence that preconditioning occurs in humans. Experimental studies with potential clinical implications as well as clinical studies evaluating ischaemic, pharmacological and anaesthetic cardiac preconditioning in the perioperative setting are reviewed. These studies reveal promising results. However, there are conflicting reports on the efficacy of preconditioning in the diseased and aged myocardium. In addition, many anaesthetics and a significant number of perioperatively administered drugs affect the activity of cardiac sarcolemmal and mitochondrial K(ATP) channels, the end-effectors of cardiac preconditioning, and thereby markedly modulate preconditioning effects in myocardial tissue. Although these modulatory effects on K(ATP) channels have been investigated almost exclusively in laboratory investigations, they may have potential implications in clinical medicine. Important questions regarding the clinical utility and applicability of perioperative cardiac preconditioning remain unresolved and need more experimental work and randomized controlled clinical trials.

[A short history of the Swiss Society of Anaesthesiology and Reanimation (SSAR)]

In common with most continental countries, anaesthesia in post-World War II Switzerland was clearly in arrears in comparison to the Anglo-American and Scandinavian countries. As early as in 1947, however, motivated young physicians left Switzerland for England, Scandinavia and the USA to familiarise themselves with the advances made in modern anaesthesia. In March, 1951, three of these pioneers, Ch. Bovay (Lausanne), W. Hügin (Basel), and K. Zeller (Winterthur), founded the Professional Association of Swiss Anaesthesiologists, thus preparing the ground for the Swiss Society of Anaesthesiology which was founded on July 5 th, 1952, on the occasion of the annual meeting of the Swiss Society of Surgery held in Zurich. Members of the first Executive Committee were Ch. Bovay, K. Zimmermann (Zurich), and W. Hügin. In 1963, the latter was appointed first Professor of Anaesthesiology in Switzerland by the University of Basel. Looking back, the 18 physicians involved in the foundation of the Society were indeed most courageous. This step towards independence is all the more admirable since the Swiss Society of Surgery, by founding a Section of Anaesthesiology, attempted to retain sovereignty over this small and new group of specialists. Only in 1954 anaesthesiology was recognised by the Swiss Medical Association as a medical specialty in its own right. In 1967 the name was changed to Swiss Society of Anaesthesiology and Reanimation (SSAR). Since coming into existence, the Society has grown more than 40-fold, with a total membership approaching 800 by 2002 end. In recent years, the SSAR took a particular interest in promoting both the training and CME of anaesthesiologists, in supporting research by its young members and in improving the quality and safety of anaesthesia.

Decreased alveolar oxygen induces lung inflammation

Molecular mechanisms of the inflammatory reaction in hypoxia-induced lung injury are not well defined. Therefore, effects of alveolar hypoxia were studied in rat lungs, exposing rats to 10% oxygen over periods of 1, 2, 4, 6, and 8 h. An increase in the number of macrophages in bronchoalveolar lavage fluid of hypoxic animals was shown between 1 and 8 h. Extravasation of albumin was enhanced after 1 h and remained increased throughout the study period. NF-kappaB-binding activity as well as mRNA for TNF-alpha, macrophage inflammatory protein (MIP)-1beta, and monocyte chemoattractant protein (MCP)-1 were increased within the first 2 h of exposure to hypoxia. Hypoxia-inducible factor (HIF)-1alpha and intercellular adhesion molecule (ICAM)-1 mRNA were upregulated between 1 and 6 h. Elimination of alveolar macrophages by intratracheal application of liposome-encapsulated clodronate led to a decreased expression of NF-kappaB binding activity, HIF-1alpha, TNF-alpha, ICAM-1, and MIP-1beta. In summary, alveolar hypoxia induced macrophage recruitment, an increase in albumin leakage, and enhanced expression of inflammatory mediators, which were mainly macrophage dependent. Alveolar macrophages appear to have a prominent role in the inflammatory response in hypoxia-induced lung injury and the related upregulation of inflammatory mediators.

Role of alveolar epithelial ICAM-1 in lipopolysaccharide-induced lung inflammation

Intercellular adhesion molecule-1 (ICAM-1) is known to play a central role in lung inflammation. Limited information, however, is available regarding the expression and biological function of ICAM-1 in the alveolar epithelial compartment. The current report analyses the expression pattern of ICAM-1 in primary cultures of rat alveolar epithelial cells (AECs) and in the rat lung following instillation of bacterial endotoxin (lipopolysaccharide (LPS)) in order to better define the role of alveolar epithelial ICAM-1. AECs stimulated in vitro with LPS were evaluated for ICAM-1 and ICAM-1 messenger ribonucleic acid content. Adherence assays with neutrophils and macrophages were performed. Endotoxin-induced ICAM-1 upregulation on AECs was demonstrated in vivo by immunofluorescence staining. In addition, the effect of intratracheally-instilled anti-ICAM-1 was assessed. Significant upregulation of ICAM-1 occurred in vitro and in vivo on AECs after LPS stimulation. Adherence assays showed a 114% increase in adhesion of neutrophils to AECs. Antibody directed against ICAM-1 reduced this adhesion by 40%. A significant reduction in the number of neutrophils in bronchoalveolar lavage fluid and whole lung was seen under airway ICAM-1 blockade. These data indicate that intercellular adhesion molecule-1 participates in the inflammatory response to lipopolysaccharide-induced lung injury in the distal airways by interacting mainly with neutrophils.

Late oesophageal perforation after intraoperative transoesophageal echocardiography

Serious haemodynamic instability occurred during emergency surgery for a perforated duodenal ulcer in a 72-year-old man with acute myocardial infarction. Intraoperative transoesophageal echocardiography was crucial for diagnosis of the location of myocardial infarction in the right ventricle and the subsequent haemodynamic management. Postoperatively, a thrombus in the right coronary artery was removed by coronary angiography. The patient's trachea was extubated on the fourth postoperative day. Another 4 days later a leak in the lower oesophagus was suspected because of pleural empyema, and verified. The patient's trachea had to be re-intubated and an oesophageal stent was inserted. The patient was discharged, fully recovered, 2 months after the operation.

Changes in intrathoracic blood volume associated with pneumoperitoneum and positioning

BACKGROUND

It is still controversial whether elevated cardiac filling pressures after the onset of pneumoperitoneum are the consequence of increased intrathoracic pressure or of increased venous return. The aim of this study was to assess the effects of pneumoperitoneum and body positioning on intrathoracic blood volume (ITBV).

METHODS

Thirty anesthetized patients were randomly assigned to have CO2-pneumoperitoneum (13 mmHg) either in a supine, in a 15 degrees head-up tilt or in a 15 degrees head-down tilt position. Measurements of ITBV and hemodynamics by the double indicator method were recorded after induction of anesthesia and application of a fluid bolus (Lactated Ringer's solution 10 ml/kg), after positioning and after induction of pneumoperitoneum.

RESULTS

Intrathoracic blood volume index (ITBVI) increased significantly after induction of pneumoperitoneum in all body positions (supine: from 18.5 +/- 3.3 -20.2 +/- 5.2 ml/kg (+6%) head-up from 16.7 +/- 3.8 - 17.4 +/- 3.7 ml/kg (+16%) and head-down: from 19.8 +/- 5.6 - 20.5 +/- 5.9 ml/kg (+14%)). Heart rate did not change significantly in any of the groups. Cardiac index showed a statistically significant change in the head-down position with pneumoperitoneum (-11%). A good correlation was found for stroke volume (SV) with ITBV (r = 0.79), but not with central venous pressure (r = 0.26). Systemic vascular resistance index increased significantly in all three groups (supine +6%, head-up +16%, head-down position +14%).

CONCLUSION

The present study indicates that the onset of pneumoperitoneum, even with moderate intra-abdominal pressures, is associated with an increased intrathoracic blood volume in ASA I/II patients.

[Participation--oriented analysis of the anesthesia workplace. A work system for anesthesia in a multidisciplinary operating room]

INTRODUCTION

The aim of this study was the detection and understanding of weak points in the ergonomic design of anaesthesia workplaces in a multidisciplinary operating room facility.

METHODS

Analysis of workplaces and of working processes by means of observations, computer-supported task recording and video-photo documentation. During guided interviews the participants were provided with material for naming-by-pointing and drawing. Subsequently, the background of the problems encountered and possible improvements were visualised.

RESULTS

Important deficits were devices not positioned within reach and view, difficulties in operating the lines connecting the patient and the devices, and inconsistent workplace layouts. These were caused by erroneous planning of the facility and disregarding ergonomic principles in equipment design. The initial improvements implemented were the development of a new concept for a flexible equipment positioning and the design of a tool for cable handling.

DISCUSSION AND CONCLUSION

Although from the very beginning of the study the anaesthesia personnel quoted the handling of the lines connecting patients and devices as the main cause for working difficulties, the external ergonomist could contribute to a broader view of the problems. The method presented here initiated a mutual learning process between ergonomist and users and resulted in a common understanding of the problems and their causes. Compared to the traditional consulting process, more time and efforts were necessary but were offset by the users' acceptance of the improvements and the prevention of design errors.

[Tumescent technique for local anesthesia]

Tumescent local anesthesia was originally used in liposuction but is also carried out for other plastic, cosmetic, dermatological procedures and for surgery of the venous system, often in outpatients. For this purpose, large amounts of fluids containing diluted lidocaine or prilocaine and epinephrine are infused subcutaneously. In this review of the literature, this technique is assessed in view of potential anesthesiological complications such as intoxication with lidocaine, prilocaine, overdosage of epinephrine or overload with fluids. While originally a lidocaine dosage of 35 mg/kg b.w. was considered to be safe, dosages were then increased to 55 mg/kg b. w. and even 90 mg/kg b. w. without data showing the safety of such high doses. Published data of plasma concentrations were obtained from small numbers of patients, showing that the concentrations were below 5 microg/ml which is considered the nontoxic range. The maximum levels were observed after 4 - 12 hours, if epinephrine was used. In a few patients, however, the values had not yet begun to decrease at the end of the 23 hours observation period. Replacing lidocaine by prilocaine shifts the problem of toxicity to that of the formation of methemoglobine, which can reach levels of more than 10 %. Data about effects of high-dose epinephrine in the literature are sparse, but tachycardia, arrhythmias and hypertension remain a major concern. Although fluids are applied subcutaneously, an overload with fluids may occur. Cases of lung edema have been reported, however, hypovolemia caused by a loss of fluid into the third space cannot be excluded. Because of these possible complications, tumescent local anesthesia should be employed in outpatients with great care. Patients should be monitored during the procedure and for a sufficient period of time thereafter by adequately trained staff. Patients with cardiac or pulmonary risk factors should not undergo tumescent local anesthesia.

Modulation of beta-adrenergic receptor subtype activities in perioperative medicine: mechanisms and sites of action

This review focuses on the mechanisms and sites of action underlying beta-adrenergic antagonism in perioperative medicine. A large body of knowledge has recently emerged from basic and clinical research concerning the mechanisms of the life-saving effects of beta-adrenergic antagonists (beta-AAs) in high-risk cardiac patients. This article re-emphasizes the mechanisms underlying beta-adrenergic antagonism and also illuminates novel rationales behind the use of perioperative beta-AAs from a biological point of view. Particularly, it delineates new concepts of beta-adrenergic signal transduction emerging from transgenic animal models. The role of the different characteristics of various beta-AAs is discussed, and evidence will be presented for the selection of one specific agent over another on the basis of individual drug profiles in defined clinical situations. The salutary effects of beta-AAs on the cardiovascular system will be described at the cellular and molecular levels. Beta-AAs exhibit many effects beyond a reduction in heart rate, which are less known by perioperative physicians but equally desirable in the perioperative care of high-risk cardiac patients. These include effects on core components of an anaesthetic regimen, such as analgesia, hypnosis, and memory function. Despite overwhelming evidence of benefit, beta-AAs are currently under-utilized in the perioperative period because of concerns of potential adverse effects and toxicity. The effects of acute administration of beta-AAs on cardiac function in the compromised patient and strategies to counteract potential adverse effects will be discussed in detail. This may help to overcome barriers to the initiation of perioperative treatment with beta-AAs in a larger number of high-risk cardiac patients undergoing surgery.

Hypoxia mediates increased neutrophil and macrophage adhesiveness to alveolar epithelial cells

Leukocyte infiltration is known to play an important role in hypoxia-induced tissue damage. There is a paucity of information on the role of hypoxia in the expression of adhesion molecules on respiratory epithelial cells. The current studies focus on the adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), their expression pattern on alveolar epithelial cells, and their biologic function under hypoxic conditions. Rat alveolar epithelial cells (AEC) were exposed to hypoxia for several time periods. With 5% oxygen, mRNA for ICAM-1 and VCAM-1 rose by 100%, peaking between 0.5 and 1 h. ICAM-1 and VCAM-1 protein showed an increase between 2 and 4 h. Neutrophil adherence to hypoxia-exposed AEC was enhanced by 115%. This increase was reduced by 83% with anti-ICAM-1 antibody. Adherence of alveolar macrophages to AEC increased by 118% and could be blocked by 95% with anti-VCAM-1 antibody. The present study shows for the first time an early increase of ICAM-1 and VCAM-1 expression on rat AEC under hypoxic conditions. These adhesion molecules are involved in increased adhesiveness of neutrophils and macrophages. Such responses might play an important role in the adhesion of leukocytes and macrophages to lung epithelial cells during hypoxic conditions.

Isolated reduction of haematocrit does not compromise in vitro blood coagulation

Low haematocrit values are generally well tolerated in terms of oxygen transport but a low haematocrit might interfere with blood coagulation. We thus sampled 60 ml of blood in 30 healthy volunteers. The blood was centrifuged for 30 min at 2000 g and separated into plasma, which contained the platelet fraction, and packed red blood cells. The blood was subsequently reconstituted by combining the entire plasma fraction with a mixture of packed red blood cells, 0.9% saline, so that the final haematocrit was either 40, 30, 20, or 10%. Blood coagulation was assessed by computerized Thrombelastograph analysis. Data were compared using repeated measures analysis of variance and post-hoc paired t-tests with Bonferroni correction. Decreasing the haematocrit from 40 to 10% resulted in a shortening of reaction time (r) and coagulation time (k), and an increase in angle alpha, maximum amplitude (MA) and clot strength (G) (all P<0.02). This pattern represents acceleration of blood coagulation with low haematocrit values. The isolated reduction in haematocrit, therefore, does not compromise in vitro blood coagulation.

Clonidine decreases propofol requirements during anaesthesia: effect on bispectral index

Assessment of the effect of clonidine on depth of anaesthesia is difficult because clonidine combines analgesic, sedative and direct haemodynamic effects. We thus evaluated the influence of clonidine on the bispectral index (BIS) and its potential dose-sparing effect on propofol. After induction of anaesthesia with target-controlled infusion of propofol and obtaining an unchanged bispectral index (pre-BIS), clonidine 4 microg kg(-1) or placebo was administered randomly to 50 patients in a double-blind manner. Subsequently, if there was a decrease in BIS we reduced the target concentration of propofol until pre-BIS was reached. The pre-BIS was maintained and a remifentanil infusion was added during surgery. The courses of the BIS, heart rate and blood pressure were recorded and the total amounts of intra-operative propofol and remifentanil were determined. Assessment of implicit memory during anaesthesia was performed with an auditory implicit memory test consisting of item sequences. Administration of clonidine resulted in a decrease in the BIS from 45 (SD 4) to 40 (6) (P<0.001), which allowed a reduction of propofol target concentration from 3.3 (0.6) to 2.7 (0.7) microg ml(-1) (P<0.001) and measured propofol concentration from 2.9 (0.6) to 2.5 (0.7) kg ml(-1) (P=0.009) in order to maintain the pre-BIS value. During subsequent surgery, propofol requirements were reduced by 20% (P=0.002) in the clonidine group and a similar amount of remifentanil was used in each group. The increase in anaesthetic depth given by clonidine can therefore be measured with bispectral EEG analysis and allows reduction of the propofol dose to achieve a specific depth of anaesthesia.

Preoperative pulmonary evaluation: facts and myths

This review summarizes recent reports on preoperative pulmonary evaluation focusing on the impact on outcome in thoracic and non-thoracic surgery. Data suggest that hitherto widely accepted pulmonary function tests do not predict perioperative complications. Therefore, they may not be considered alone to decide on the patient's operability. So-called prohibitive lung function parameters should no longer be used to deny a potentially curative lung resection. A more clinically oriented, interdisciplinary approach to severely compromised patients may be best suited to discuss and solve their problems.

Physiological properties of blood substitutes

Blood substitutes (modified hemoglobin solutions, perfluorocarbon emulsions) serve as artificial oxygen carriers and are alternatives to blood transfusions. Hemoglobin solutions mimic the sigmoidal oxygen dissociation curve of natural blood. Perfluorocarbon emulsions exhibit a linear relation between PO2 and dissolved oxygen. The most advanced substances may enter medicine in few years.

[Cardiovascular stress protection following anesthesia induction. Comparison of clonidine and esmolol]

Alpha-2-adrenoceptor-agonists as well as cardioselective betareceptor-antagonists have been shown to blunt stress response due to tracheal intubation. The purpose of our study was to investigate,whether clonidine or esmolol is more efficient to attenuate stress response due to intubation.44 patients were randomly assigned to receive either clonidine (n=22; 3 microg/kg) or esmolol (n=22; 2 mg/kg) immediately prior to a standardized induction of anaesthesia. Heart rate, arterial blood pressure, cardiac output, epinephrine and norepinephrine plasma concentrations were measured before,during and 10 min after intubation. Blood pressure was measured invasively and cardiac output was determined by transthoracic echocardiography. Absolute values and increase of mean arterial pressure and norepinephrine plasma concentrations were significantly less in the clonidine group (p<0,05). Clonidine (3 microg/kg) is more efficient than esmolol (2 mg/kg) in blunting stress response due to endotracheal intubation.

Low- and medium-molecular-weight hydroxyethyl starches: comparison of their effect on blood coagulation

BACKGROUND

High-molecular-weight hydroxyethyl starch (HES) compromises blood coagulation more than medium-molecular-weight HES. The authors compared medium molecular weight HES (200 kd [HES200]) and low-molecular-weight HES (70 kd [HES70]).

METHODS

In a prospective, double-blind, randomized-sequence crossover study, 22 male volunteers received 15 ml/kg HES200 and HES70. Blood samples were taken before and 5 min, 30 min, 1 h, 2 h, 4 h, 8 h, and 24 h after infusion. The following parameters were analyzed at all time points: prothrombin time, activated partial thromboplastin time, fibrinogen, factor VIII, antigenetic and functional von Willebrand factor, platelets, Thrombelastograph analysis parameters (reaction time, coagulation time, maximum amplitude, angle alpha, and clot lysis 30 and 60 min after maximum amplitude), ionized calcium, hematocrit, HES plasma concentration, molecular weight (weight average and number average), molar substitution, and polydispersity (weight average/number average). Repeated-measures analysis of variance (P < 0.05) was used to compare the response of the aforementioned parameters to the infusion of HES70 and HES200.

RESULTS

Both HES solutions had a significant impact on all parameters. A slightly greater compromise with HES200 was found in activated partial thromboplastin time (P = 0.010), factor VIII (P = 0.009), antigenetic von Willebrand factor (P = 0.041), functional von Willebrand factor (P = 0.026), maximum amplitude (P = 0.008), and angle alpha (P = 0.003). No difference was established with the other parameters. HES concentration (P < 0.001), weight average (P < 0.001), number average (P < 0.001), and polydispersity (P < 0.001) were higher with HES200. There was no difference with molar substitution (P = 0.091).

CONCLUSIONS

Low-molecular-weight hydroxyethyl starch (70 kd) compromises blood coagulation slightly less than HES200, but it is unclear whether this is clinically relevant.

Comparison of a new video-optical intubation stylet versus the conventional malleable stylet in simulated difficult tracheal intubation

Handling and efficacy of a new video-optical intubation stylet were assessed in a simulated difficult tracheal intubation setting and compared with a conventional malleable stylet. Forty-five anaesthetists performed 10 tracheal intubations using both techniques. Laryngoscopy was performed by the observer, who created a grade 3 view according the classification by Cormack and Lehane. The time taken to place the tracheal tube and the final tracheal tube positions were documented. Mean (SD) intubation time for the video-optical stylet was 20.4 (7.7) s and for the malleable stylet 10.2 (3.3) s (p<0.01). With the video-optical stylet the trachea was correctly intubated in all 225 attempts; with the malleable stylet 44 (19.6%) oesophageal and 44 (19.6%) endobronchial intubations occurred (p<0.01). The video-optical intubation stylet enabled us to recognise inappropriate tracheal tube positions and to correct them immediately. This equipment can be considered a reliable and effective tool for management of the difficult airway.

Preoperative clonidine attenuates stress response during emergence from anesthesia

STUDY OBJECTIVES

To investigate whether a single preoperative IV dose of clonidine blunts the hemodynamic and hyperadrenergic responses not only to intubation, but also to extubation.

DESIGN

Randomized, double-blind, placebo-controlled study.

PATIENTS

29 ASA physical status I and II patients (ages 18-65) who were scheduled for noncardiac, elective surgery. Patients were randomly assigned to either receive clonidine 3 microg/kg IV immediately before anesthesia induction or placebo.

INTERVENTIONS

Insertion of a 14 G cannula in a large cubital vein for the determination of plasma catecholamines using local anesthesia. Insertion of a radial artery catheter for measuring blood pressure (BP) using local anesthesia. Transthoracic echocardiography to determine cardiac output (CO).

MEASUREMENTS

Heart rate (HR), mean arterial pressure (MAP), CO, and plasma catecholamine concentrations. Measurements were performed: before induction (baseline), during intubation, 10 min after intubation, after surgery, during extubation, and 10 min after extubation.

MAIN RESULTS

During intubation MAP, HR, and CO were lower in the clonidine group. Compared with baseline measurements, MAP and CO increased less in the clonidine group during intubation. During extubation, MAP was lower in the clonidine group. CO and MAP increased less as compared with baseline measurements in the clonidine group. Compared with the measurements after surgery CO less in the clonidine group during extubation (p < 0.05 for all results).

CONCLUSIONS

A single preoperative IV dose of clonidine (3 microg/kg) blunts the hemodynamic responses due to extubation in noncardiac surgery of intermediate duration.

Citrate storage affects Thrombelastograph analysis

BACKGROUND

Thrombelastograph analysis (TEG) is used to evaluate blood coagulation. Ideally, whole blood is immediately processed. If impossible, blood may be citrated and assessed after recalcification. No data describe the effect of such treatment and storage on TEG parameters.

METHODS

Three studies were performed in 90 surgical patients. In 30 patients, blood was citrated (1:10, 0. 129 M) and recalcified (20 microl 2 M CaCl2 to 340 microl citrated blood), and TEG was performed with native blood and after recalcification after 0, 15, and 30 min of citrate storage. In another 30 patients, TEG was performed with citrated blood recalcified immediately and after 1-72 h storage. In a third study, thrombin-antithrombin complex, prothrombin fragment 1+2, and beta-thromboglobulin were measured (using enzyme-linked immunoabsorbant assay tests) at corresponding time points. Data were compared using repeated-measures analysis of variance and post hocpaired t tests.

RESULTS

TEG parameters were different in recalcified citrated blood compared with native blood (P < 0.05) and changed significantly during 30-min (P < 0.025) and 72-h (P < 0.001) citrate storage. TEG parameters measured between 1 and 8 h of citrate storage were stable. Thrombin-antithrombin complex and prothrombin fragment 1+2 values were not elevated in native blood. After 30 min of citrate storage a gradual thrombin activation was observed, as evidenced by increasing thrombin-antithrombin complex and prothrombin fragment 1+2 values (P < 0.05). beta-Thromboglobulin level was increased after 2 and 8 h of citrate storage (P < 0.01).

CONCLUSIONS

Analysis of native blood yields the most reliable TEG results. Should immediate TEG processing not be possible, citrated blood may be used if recalcified after 1-8 h.

Lipopolysaccharide induces functional ICAM-1 expression in rat alveolar epithelial cells in vitro

Lipopolysaccharide (LPS)-induced lung inflammation is known to increase pulmonary intercellular adhesion molecule-1 (ICAM-1) expression. In the present study, L2 cells, a cell line of alveolar epithelial cells, were stimulated with LPS, and ICAM-1 expression was studied. ICAM-1 protein on L2 cells peaked at 6 (38% increase; P < 0.01) and 10 (48% increase; P < 0.001) h after stimulation with Escherichia coli and Pseudomonas aeruginosa LPS, respectively. ICAM-1 mRNA expression was markedly increased, with a peak at 2-4 (E. coli) and 4-6 (P. aeruginosa) h. Adherence assays of neutrophils to LPS-stimulated L2 cells showed a threefold increase in adherence (P < 0.001). Pretreatment of the neutrophils with anti-lymphocyte function-associated antigen-1 and anti-Mac-1 antibodies reduced adherence by 54% (P < 0.001). Analysis of immunofluorescence staining for ICAM-1 showed an exclusive apical expression of ICAM-1. These results indicate that LPS upregulates functional active ICAM-1 on the apical part of the membrane in rat pneumocytes.

Factors influencing the individual effects of blood transfusions on oxygen delivery and oxygen consumption

OBJECTIVE

To determine factors influencing the individual effects of blood transfusions regarding oxygen delivery and consumption.

DESIGN

Chart review.

SETTING

A university hospital cardiosurgical intensive care unit.

PATIENTS

Sixty-seven patients with 170 transfusion events evaluated.

INTERVENTIONS

Blood transfusion.

MEASUREMENTS AND MAIN RESULTS

Measurements were performed before and after a blood transfusion, separated by 302 +/- 13 mins (mean +/- SEM). The individual increase in cardiac index resulting from a blood transfusion was inversely related to cardiac index before transfusion (p < .001), oxygen delivery index before transfusion (p < .001), and oxygen consumption index before transfusion (p < .001). The individual increase in oxygen delivery index was inversely related to oxygen consumption index before transfusion (p < .001). The individual increase in oxygen consumption index was inversely related to oxygen consumption index before transfusion (p < .001). Individual changes in cardiac index, oxygen delivery index, and oxygen consumption index were not significantly related to preoperative ejection fraction (25%-87%), age (32-81 yrs), and pretransfusion hemoglobin concentration (5.0-11.8 g/dL).

CONCLUSION

In adult patients after cardiovascular surgery, oxygen delivery- and oxygen consumption-related variables predict the individual response to blood transfusions better than do patient characteristics such as preoperative ejection fraction, age, and pretransfusion hemoglobin concentration. Including oxygen delivery and oxygen consumption, variables into the transfusion decision, thus, may enable a more individual use of allogeneic blood in specific situations.

Hyaluronan induces monocyte chemoattractant protein-1 expression in renal tubular epithelial cells

Hyaluronan (HA) is a nonsulfated glycosaminoglycan that accumulates in the renal interstitium in immune-mediated kidney diseases. The functional significance of such HA deposition in the kidney has not been elucidated. Several studies have suggested that HA may exhibit proinflammatory effects. Since chemokines such as monocyte chemoattractant protein-1 (MCP-1) play an important role in the recruitment of leukocytes in renal injury, this study tested whether HA and its fragments could promote MCP-1 production by renal parenchymal cells. Mouse cortical tubular cells were stimulated with fragmented HA or with high molecular weight HA (Healon) in vitro and were examined for MCP-1 expression. Fragmented HA, but not Healon, increased MCP-1 mRNA within 30 min with a peak after 2 h. In addition, a 10-fold increase of MCP-1 protein in the supernatant was found after a 6-h stimulation with fragmented HA. The enhanced MCP-1 mRNA and protein expression in response to HA was dose-dependent between 1 and 100 microg/ml. Upregulation of MCP-1 protein production could be blocked by preincubation with actinomycin D or cycloheximide, suggesting that MCP-1 mRNA and protein expression in response to HA are based on de novo synthesis. The HA-stimulated MCP-1 production was also inhibited with anti-CD44 antibodies, suggesting that MCP-1 is upregulated at least in part by signaling through CD44. In summary, fragmented HA markedly stimulates renal tubular MCP-1 production by mechanisms that involve binding to the HA receptor CD44. It is hypothesized that the accumulation of HA in immune renal injury could participate in the recruitment and activation of inflammatory cells in vivo through production of MCP-1.

Compromised blood coagulation: an in vitro comparison of hydroxyethyl starch 130/0.4 and hydroxyethyl starch 200/0.5 using thrombelastography

We compared the effects of progressive in vitro hemodilution (30% and 60%) on blood coagulation in 80 patients receiving one of two different 6% hydroxyethyl starch (HES) solutions using thrombelastography (TEG). The newly developed solution has a mean molecular weight of 130 kD and a degree of substitution, defined as the average number of hydroxyethyl groups per glucose moiety, of 0.4 (HES 130/0.4); the conventional solution has a mean molecular weight of 200 kD and a degree of substitution of 0.5 (HES 200/0.5). Both HES solutions significantly compromised blood coagulation, as seen by an increase in reaction time and coagulation time and a decrease in angle alpha, maximal amplitude, and coagulation index (all P < 0.05). There was no difference between HES 130/0.4 and HES 200/0.5 diluted blood (P > 0.05 for all TEG variables). When analyzing the intrinsic HES effect by taking hemodilution with 0.9% saline into account, progressive hemodilution with both HES solutions resulted in an increasing clot lysis (P < 0.05 after 60 min). Again, there was no difference between HES 130/0.4 and HES 200/0.5 diluted blood. We conclude that HES 130/ 0.4 and HES 200/0.5 compromise blood coagulation to the same degree.

IMPLICATIONS

Progressive in vitro hemodilution using hydroxyethyl starch (HES) compromises blood coagulation. We observed similar effects of a new HES solution with a mean molecular weight of 130 kD and a degree of substitution of 0.4 (HES 130/0.4), compared with the conventional HES 200/0.5.

Perioperative reliability of an on-site prothrombin time assay under different haemostatic conditions

Perioperative use of laboratory coagulation assays is limited by the delay in obtaining results. The management of haemostasis during major surgical procedures requires rapid and accurate measurement of the prevailing coagulation status. In this prospective study, we have evaluated the reliability of on-site prothrombin time assessed by the portable coagulation monitor CoaguChek-Plus compared with standard laboratory assays during elective non-cardiac surgery. Sixty-two patients were assigned to one of three groups: group A = normal preoperative coagulation where minor intraoperative blood loss is expected; group B = normal preoperative coagulation where major intraoperative blood loss is expected; and group C = preoperative anticoagulation and minor intraoperative blood loss expected. On-site prothrombin time and laboratory prothrombin time showed poor correlation in group A (r2 = 0.24; bias (2 SD) 1.80 (3.34) S) and group B (r2 = 0.30; 1.43 (3.12) S). The correlation in group C was better (r2 = 0.71; 1.41 (1.92) S). We conclude that prothrombin time measured with the CoaguCheck-Plus monitor did not appear to be suitable for the management of haemostasis.

Substantial changes in arterial blood gases during thoracoscopic surgery can be missed by conventional intermittent laboratory blood gas analyses

Substantial and clinically relevant changes in arterial blood gases are likely to occur during thoracoscopic surgery with one-lung ventilation (OLV). We hypothesized that they may be missed when using the conventional intermittent blood gas sampling practice. Therefore, during 30 thoracoscopic procedures with OLV, the sampling intervals between consecutive intermittent laboratory blood gas analyses (BGA) were evaluated with respect to changes of PaO2, PaCO2, and pHa ([H+]) using a continuous intraarterial blood gas monitoring system. Frequency and timing of BGA were based on the clinical judgment of 16 experienced anesthesiologists who were blinded to the continuously measured values. Extreme fluctuations of PaO2 (37-625 mm Hg), PaCO2 (27-56 mm Hg), and pHa (7.24-7.51) were observed by continuous blood gas monitoring. During 63% of all sampling intervals, PaO2 decreased >20% compared with the preceding BGA value, which remained undetected by intermittent analysis. In 10 patients with a continuously measured minimal PaO2 value < or = 60 mm Hg, the preceding BGA overestimated this minimal PaO2 by > 47%. Correspondingly, PaCO2 increases of > 10% were observed in 35% of all sampling intervals, and [H+] increases of > 10% were observed in 24% of all sampling intervals. Because these blood gas changes were not reliably detected by using noninvasive monitoring and their magnitude is not predictable during OLV, intermittent BGA with short sampling intervals is warranted. In critical cases, continuous blood gas monitoring may be helpful.

IMPLICATIONS

The magnitude of blood gas changes during thoracoscopic surgery with one-lung ventilation is not predictable and not reliably detected by noninvasive monitoring. Using a continuous intraarterial blood gas monitoring device, we demonstrated that intermittent laboratory blood gas analysis with short sampling intervals is warranted to detect arterial hypoxemia.

The effect of potato starch derived and corn starch derived hydroxyethyl starch on in vitro blood coagulation

We have compared the effects of progressive in vitro haemodilution (30% and 60%) with potato starch derived hydroxyethyl starch and corn starch derived hydroxyethyl starch on blood coagulation in 80 patients using thrombelastography. Both solutions significantly compromised blood coagulation as evidenced by an increase in coagulation time and decrease in angle alpha, maximum amplitude and coagulation index (p < 0.05). Blood coagulation was more compromised during haemodilution with potato starch derived hydroxyethyl starch as compared with corn starch derived hydroxyethyl starch (p < 0.05). When taking the effect of haemodilution with 0.9% saline into account, haemodilution with both hydroxyethyl starch solutions also augmented clot lysis (p < 0.05), with potato starch derived hydroxyethyl starch having a greater effect than corn starch derived hydroxyethyl starch (p < 0.05). We conclude that potato starch derived hydroxyethyl starch compromises in vitro blood coagulation more than corn starch derived hydroxyethyl starch.

Characterization of rat lung ICAM-1

OBJECTIVE AND DESIGN

We expressed soluble rat ICAM-1, generated a polyclonal anti-ICAM-1 antibody, and studied ICAM-1 upregulation in lung inflammatory conditions. Bacterial and baculovirus expression systems were employed.

MATERIAL

250 g adult, male Long Evans rats were used. For in vitro studies, rat pulmonary artery endothelial cells (RPAEC), rat alveolar macrophages and aortic rings were stimulated (as described below) and evaluated for ICAM-1 expression.

TREATMENT

RPAEC and macrophages were stimulated with lipopolysaccharide (LPS) and recombinant murine tumour necrosis factor alpha (TNFalpha). In vivo immunoglobulin G (IgG) immune complex-induced lung injury was employed.

METHODS

Enzyme-linked immunoassay (ELISA) Western and Northern blot analyses and immunohistochemical evaluations were performed. All experiments were done at least in duplicate. Data were analyzed by two-tailed Student's t-test.

RESULTS

ICAM-1 expression of RPAEC was time- and dose-dependent, peaking at 6h after LPS-stimulation. LPS and TNFalpha each enhanced ICAM-1 expression on alveolar macrophages (reaching a maximum at 2 h). In IgG immune complex-induced lung injury, ICAM-1 mRNA isolated from whole lung peaked at 4 h, while lung ICAM- I protein peaked at 6 h.

CONCLUSIONS

Quantitation of ICAM-1 expression in vitro and in vivo suggests that ICAM-1 plays a central role in two lung inflammatory models. Furthermore, lung ICAM-1 upregulation involves at least two cell types: vascular endothelial cells and alveolar macrophages.

[Opioids in treatment of chronic noncancer pain]

Opioids have been accepted as appropriate analgesic treatment for pain associated with cancer. However, controversy exists about their use for chronic noncancer pain. Reasons for reluctance are concerned about efficacy and potential adverse effects such as respiratory depression, addiction, physical dependence or intolerance. Many physicians worry about liability and legal restrictions. Nevertheless, pain management of chronic severe pain with opioids can be the only help when alternative methods are too risky of fail to be effective. This article briefly reviews the published literature on this topic and discusses some practical guidelines for the use of opioids in the treatment of non-cancer pain.