Perioperative concentrations of catecholamines in the cerebrospinal fluid and plasma during spinal anesthesia.

BACKGROUND: Catecholamine release is a physiological response to stress. The extent to which perioperative stress provokes the central release of catecholamines, which modulate pain perception in the spinal cord, still remains unknown. The perioperative course of catecholamine concentrations in the cerebrospinal fluid (CSF) and plasma was examined. METHODS: A prospective study was performed in 25 patients (ASA III, 60-84 years) undergoing elective hip joint replacement in spinal catheter anesthesia. The concentrations of dopamine, epinephrine and norepinephrine in the CSF and plasma were measured before anesthesia, immediately after surgery, and 6 and 24 h post-operatively. RESULTS: In most patients, dopamine and epinephrine were not detectable in CSF. CSF-norepinephrine concentrations decreased from median [interquartile-range] 159 [124;216] pre-anesthesia to 116 [79;152] pmol/l immediately post-operatively and were slightly elevated 24 h post-operatively (180 [134;302] pmol/l) (P=0.05). Dopamine plasma concentrations were not detectable or were barely above the detection threshold. Plasma epinephrine increased from 61 [28;77] pmol/l pre-anesthesia to 112 [69;138] pmol/l 6 h post-operatively and returned to baseline 24 h post-operatively (P=0.001). Plasma norepinephrine concentrations increased intra-operatively from 298 [249;422] to 556 [423;649] pmol/l and remained elevated 24 h after surgery (P=0.009). There was no association between changes in CSF or plasma norepinephrine or epinephrine concentrations and changes in heart rate (HR) or mean arterial pressure (MAP). CONCLUSION: During spinal anesthesia for elective hip joint replacement, norepinephrine concentrations were greater in plasma than in CSF. CSF dopamine and epinephrine concentrations were essentially undetectable. The changes in CSF-norepinephrine concentrations and the changes of plasma norepinephrine concentrations showed no association with each other; nor were there correlations between clinical stress parameters (HR, MAP) or visual analog scale pain, and the changes in CSF norepinephrine concentrations.

Perioperative changes in cerebral ischemic markers in the cerebrospinal fluid after preoperative nimodipine treatment.

BACKGROUND: Elderly patients with previous organ damage are at risk for minor neurologic deficits after major surgery. Spinal catheter analgesia is used whenever possible in this group and enables regular cerebrospinal fluid (CSF) sampling. Nimodipine, a calcium blocker, may have neuroprotective effects. We examined whether preoperative treatment with nimodipine affects ischemic markers in the CSF during extracranial surgery. METHODS: We performed a prospective, randomized, placebo-controlled, double-blind study in patients (ASA III or IV, 65-85 years) that underwent elective implantation surgery of the hip joint with intrathecal catheter anesthesia. Starting 15 h before surgery, patients received either 30 microg x kg(-1) h(-1) of nimodipine (n = 20) or 0.9% saline solution (placebo, n = 23) as a central venous infusion. The concentrations of neuron-specific enolase, hypoxanthine, creatine-kinase, lactate and pH in the CSF were determined before and immediately after surgery as well as 6 and 24 h after surgery. RESULTS: Before surgery, the baseline CSF pH was normal in all patients. Immediately after surgery it fell significantly to 7.08 +/- 0.29 in the placebo group and non-significantly to 7.27 +/- 0.38 in the treatment group; all values were normalized at 6 and 24 h after surgery in both groups. In the placebo group, lactate levels rose significantly from 1.48 +/- 0.28 mmol l(-1) before surgery to 1.77 +/- 0.27 mmol l(-1) immediately after surgery, and to 2.03 +/- 0.32 mmol l(-1) 24 h after surgery. In the treatment group, lactate concentrations remained stable up to 6 h after surgery (1.55-1.62 mmol l-1), while an increase to 2.10 +/- 0.48 mmol l(-1) was observed 24 h after the operation. Neuron-specific enolase, hypo-xanthine and creatine-kinase showed no change in either group. CONCLUSION: In conclusion, preoperative nimodipine treatment reduced intraoperative CSF acidosis and delayed surgery-related increases in lactate concentration in the CSF by several hours in elderly, comorbid patients at risk for minor postoperative neurologic deficits.

[Clinical significance of S-(+)-ketamine]. / Klinischer Stellenwert des S-(+)-Ketamin.

Among anaesthetic drugs, ketamine occupies a special position. biochemically, ketamine is a racemate consisting of equal shares of two optical enantiomers. Pharmacological investigations show differences between those enantiomers in both qualitative and quantitative properties. Furthermore, clinical superiority of S-(+)-ketamine has been described in different therapeutic studies with regard to anaesthetic potency, the extent of analgesia, effects and side effects during and after the operation, and undiserable psychological dysfunction. On a neuropharmacological basis, the clinical superiority of S-(+)-ketamine is due to its effect on NMDA receptors in central nervous tissue, opioid receptors on both central and peripheral levels, and noradrenergic, dopaminergic, and serotoninergic mechanisms. The main problems associated with the ketamine racemate in clinical use are desirable psychological dysfunction and a prolonged period of arousal. There are grounds for the assumption that the use of S-(+)-ketamine will minimise those problems without reducing anaesthetic potency or restricting the advantages of ketamine anaesthesia.

[Is the elimination of osteosarcoma cells with intraoperative "mesh autotransfusion" and leukocyte depletion filters possible?]. / Ist die Elimination von Osteosarkomzellen durch "maschinelle Autotransfusion" und Leukozyten-Depletionsfilter möglich?

UNLABELLED: Intraoperative autotransfusion is contraindicated in cancer surgery because of the possible risk of systemic tumor spread. The aim of the present study was to investigate whether a cell saver in combination with a white blood cell depletion filter can remove osteosarcoma cells. METHODS: A defined number of osteosarcoma cells from an established cell line were added to red cell concentrates and Ringer solution. The tumor cell concentration was 1000/ ml in the first five experiments, 7111/ml in test no. 6, 1667/ml in test no. 7 and 167/ml in test no. 8. Following thorough mixing, each unit was processed separately by a cell saver (DIDECO BT 795/P) in its normal operation mode to produce a red cell concentrate. This red cell concentrate was filtered using a leukocyte depletion filter (PALL BPF 4). Samples were taken before and after processing with the autotransfuser and after filtration with the white cell depletion filter. Cytospin specimens from all samples were examined for osteosarcoma cells by three different methods (Papanicolaou stain, Vimentin antibodies, DNA analysis). RESULTS: After processing with the autotransfuser, tumor cells were identified in the red cell concentrate. No osteosarcoma cells were evident after the combined use of cell saver and leukocyte depletion filter. CONCLUSION: The sole use of the autotransfuser DIDECO BT 795/P during osteosarcoma surgery is not recommended because of the potential danger of retransfusion of malignant cells. In combination with the leukocyte depletion filter PALL BPF 4, no osteosarcoma cells were identified in the red cell concentrate. Since the adhesiveness of tumor cells from established cell lines may be different from that of tumor cells in the intraoperative salvaged blood, further studies with blood from the surgical field are necessary to determine the efficacy of white cell depletion filters to eliminate osteosarcoma cells.

[A possible risk for geriatric risk patients caused by intraoperative disorder of cerebral energy utilization?]. / Ein mögliches Risiko für geriatrische Risikopatienten durch eine intraoperative Störung der zerebralen Energieutilisation?

OBJECTIVE: This study was carried out on cerebrospinal fluid (CSF) to investigate the perioperative course of certain ischaemic markers, namely neurone-specific enolase (NSE), creatine kinase (CK-BB), hypoxanthine, and lactate in order to identify a disturbed cerebral energy utilisation which could be responsible for the development of temporary mental dysfunctions. Those dysfunctions are characterised by preserved memory content and perception, but the coordination and association of these functions are disturbed. Typical clinical signs are motor restlessness, disordered emotions, and symptoms of dementia. Little is known about the aetiology of those symptoms, but they are most likely due to various events, such as direct drug effects, the extent of surgical trauma, sensorial deprivation, and disturbed perfusion. METHODS: Eight orthopaedic patients (ASA III or IV) scheduled for removal of their total hip replacement were anaesthetised by catheter-spinal anaesthesia (CSA) for pain relief in combination with standardised, modified neuroleptanalgesia (NLA). At six defined times (15 hours preoperatively, immediately before and after surgery and 6, 24, and 36 hours postoperatively) CSF samples were drawn and the ischaemic markers were determined by means of radioimmunoassay (NSE), electrophoresis (CK-BB), photometry (lactate), and high-pressure liquid chromatography (hypoxanthine). The release of ischaemic markers into CSF correlates linear with the extent of ischaemic brain damage. RESULTS: Mean concentrations of the following ischaemic markers increased in all patients intraoperatively: NSE from 12.3 ng/ml to 13.4 ng/ml, hypoxanthine from 1.86 mumol/l to 3.73 mumol/l, and lactate from 1.4 mmol/l to 2.0 mmol/l respectively, all of which returned to normal within 36 hours. The CK-BB concentrations were all within normal values and not affected by the operation during this investigation. CONCLUSION: Although no clinical signs of temporary mental dysfunction have been observed, the results indicate that in CSF ischaemic markers temporarily undergo certain changes in their concentrations during the removal of total hip replacements in elderly patients. These changes are reason for assuming that risk patients may suffer a temporary disturbed cerebral energy utilisation intraoperatively, even if stable clinical and cardiovascular conditions prevail under anaesthesia. Such a temporary ischaemic penumbra might be responsible for the postoperative development of temporary mental dysfunctions.

Intercostal nerve block, interpleural analgesia, thoracic epidural block or systemic opioid application for pain relief after thoracotomy?

The purpose of this study was to investigate the effect of different pain-relief methods (regional and systemic) following thoracotomies on the cardiovascular system, pulmonary gas exchange, various endocrine parameters and subjective perception. A further aspect was to evaluate the benefits of interpleural analgesia as a new regional technique against already established regional techniques, such as intercostal nerve block and thoracic epidural block. All postoperative pain methods led to a significant time-dependent reduction of the adrenaline concentrations in plasma while the noradrenaline concentrations did not change significantly. There were no statistical differences in catecholamine concentrations among the different study groups, although the mean concentrations of adrenaline in patients having a thoracic epidural block for pain relief were lower in comparison to the findings in other groups. The plasma concentrations of the "stress metabolites", such as glucose, free fatty acids and lactate, as well as the haemodynamic (mean arterial pressure, heart rate) and pulmonary parameters (blood gas analyses), showed no significant differences among groups. In contrast to the other pain-relieving methods, interpleural analgesia did not lead to sufficient pain relief in that 7 out of 10 patients needed supplementary systemic opioid therapy. Therefore, interpleural analgesia for pain relief following thoracotomies cannot be recommended.