bluuebunny/crossref_metadata_2025 huggingface dataset:
The dissociation of sedative from spinal antinociceptive effects following administration of a novel alpha‐2‐adrenoceptor agonist, MPV‐2426, in the locus coeruleus in the rat
Authors: Xu M. , Wei H. , Kontinen V. K. , Kalso E. , Pertovaara A.
Published: March 2003

Background: MPV‐2426 is a novel alpha‐2‐adrenoceptor agonist developed for spinal pain therapy. In the present study we characterized its sedative and antinociceptive properties following microinjections into the brainstem and intrathecally at the lumbar spinal cord level.

Methods: Sedative effects of MPV‐2426 were assessed in a locomotion measuring device following unilateral microinjection into the locus coeruleus (LC) of the brainstem or 1–2 mm rostral to the LC in rats. Antinociceptive effects induced by MPV‐2426 in the brainstem, and for comparison intrathecally at the lumbar spinal cord level, were determined with a tail‐flick test. Dexmedetomidine was used as the reference alpha‐2‐adrenoceptor agonist.

Results: MPV‐2426 produced a dose‐related hypolocomotive/ sedative effect, which was significantly stronger following microinjection into the LC than 1–2 mm rostral to the LC. The sedation induced by MPV‐2426 was reversed by atipamezole (1 mg/kg s.c.), an alpha‐2‐adrenoceptor antagonist. The sedative potency of dexmedetomidine, the reference alpha‐2‐adrenoceptor agonist, was stronger and less dependent on the exact injection site in the brainstem. Following microinjections at sedative doses in the brainstem, only dexmedetomidine produced a significant antinociceptive effect in the tail‐flick test. When microinjected into the lumbar spinal cord, MPV‐2426 and dexmedetomidine had an equally strong antinociceptive effect in the tail‐flick test.

Conclusion: The results indicate that the sedative potency of MPV‐2426 is considerably weaker than that of dexmedetomidine. Additionally, the spread of MPV‐2426 within the central nervous system is more limited than that of dexmedetomidine. This could explain why MPV‐2426 is sedative only when injected into the LC while antinociceptive effect is obtained when it is injected intrathecally at the lumbar spinal cord level.
Epileptiform EEG during sevoflurane mask induction: Effect of delaying the onset of hyperventilation
Authors: Vakkuri A. , Jäntti V. , Särkelä M. , Lindgren L. , Korttila K. , Yli‐Hankala A.
Published: March 2003

Background: Hyperventilation during sevoflurane‐N2O‐O2 mask induction in adults is associated with a hyperdynamic circulatory response and epileptiform electroencephalogram (EEG). We tested the hypothesis that delaying onset of hyperventilation will prevent severe (periodic) epileptiform EEG and hyperdynamic response.

Methods: Thirty patients were randomized to receive either delayed (group D, n=15) or immediate (group I, n=15) onset of hyperventilation during sevoflurane (8% in N2O 50%) mask inhalation induction with single‐breath method for unconsciousness. Fifteen patients were allowed to breathe spontaneously for 2 min after loss of consciousness and controlled hyperventilation (ETCO2 <4%) was started thereafter. In 15 patients controlled hyperventilation was started immediately after loss of consciousness. EEG was recorded, and mean arterial pressure (MAP) and heart rate (HR) registered.

Results: Epileptiform EEG patterns were seen in 13 patients in group I and in 9 patients in group D (n.s.). Periodic epileptiform discharges (PED) tended to occur more often in group I (P=0.07). Heart rate and MAP were higher in group I than in group D from 2 min to 3 min (P<0.05), and both HR and MAP rose significantly from the baseline in group I. In group D, HR but not MAP rose significantly from baseline.

Conclusion: Regardless of its timing, hyperventilation at a high sevoflurane concentration produced severe epileptiform EEG with a hyperdynamic response. PED tended to occur more often with immediate onset of hyperventilation (
Note).
Preoperative treatment with recombinant human erythropoietin or predeposit of autologous blood in women undergoing primary hip replacement
Authors: Gombotz H. , Gries M. , Sipurzynski S. , Fruhwald S. , Rehak P.
Published: March 2003

Background: Controversy exists about the advantages of predeposit of autologous blood (PDAB), and whether more comfortable blood conservation regimens may yield comparable results. To test the hypothesis that preoperative treatment with recombinant human erythropoietin (rHuEPO) with or without acute concomitant normovolaemic haemodilution (ANHD) is as effective as PDAB in reducing allogeneic blood transfusions, we conducted a prospective randomised study in women undergoing primary hip replacement.

Methods: Sixty consecutive female patients scheduled for primary hip replacement and suitable for PDAB were randomly assigned to one of 3 groups. Group I (EPO) and II (ANHD) received 600 U/kg rHuEPO s.c. and 100 mg iron saccharate i.v. on day 14 and, if needed, on day 7 before surgery. Additionally, in group II acute normovolaemic haemodilution (ANHD) was implemented after induction of anaesthesia. In group III (PDAB) conventional PDAB up to 3 U, without volume replacement but with concomitant oral iron therapy, was performed starting 4 weeks before surgery.

Results: The blood conservation methods resulted in a comparable net gain of red cells in all 3 groups until the day of surgery. Because of the withdrawal of autologous blood, haemoglobin values before surgery were lower in the PDAB group than in the EPO and ANHD groups, and during surgery were lower in the PDAB and ANHD groups than in the rHuEPO‐only group. Applying moderate ANHD in conjunction with preoperative rHuEPO treatment did not yield an incremental decrease in allogeneic transfusions. There was no difference between the groups in the number of patients who received allogeneic transfusions or in the total number of allogeneic units transfused.

Conclusions: Withdrawal of autologous blood is associated with lower pre‐ and intraoperative haemoglobin levels when compared to preoperative augmentation of red cell mass using rHuEPO. As a measure to reduce allogeneic transfusion requirements, preoperative treatment with rHuEPO may be as effective as standard predeposit of autologous blood in women undergoing primary hip replacement, but requires less preoperative time.
Total versus tube‐related additional work of breathing in ventilator‐dependent patients
Authors: Haberthür C. , Elsasser S. , Eberhard L. , Stocker R. , Guttmann J.
Published: March 2003

Background: In tracheally intubated or tracheostomized spontaneously breathing patients, tube resistance can highly increase the patient’s work of breathing. In this study we focused upon the relationship between total (WOBtot) and tube‐related additional inspiratory work of breathing (WOBadd) and compared different ventilatory modalities for proper tube compensation.

Methods: In ten tracheostomized spontaneously breathing patients we measured WOBtot and WOBadd in the continuous positive airway pressure (CPAP) mode, under inspiratory pressure support of 5, 10, and 15 cmH2O in the pressure support ventilation (PSV) mode, and under flow‐adjusted pressure support in the automatic tube compensation (ATC) mode. WOBadd and WOBtot were calculated on the basis of measured tracheal pressure and esophageal pressure, respectively. Inspiratory peak tracheal pressure above PEEP was taken as an estimate of pressure support beyond mere tube compensation (i.e., overcompensation).

Results: The percentage of the tube‐related WOBadd on WOBtot in the CPAP mode was 52%. It decreased with increasing pressure support in the PSV mode from 32% (PSV 5 cmH2O) to 17% (PSV 15 cmH2O). WOBadd was only 15% of WOBtot in the ATC mode. In contrast to the other ventilatory modes, reduction of WOBadd in the ATC mode was achieved with the smallest amount of overcompensation, i.e. with minimal pressure assist beyond mere tube compensation.

Conclusion: In tracheally intubated or tracheostomized spontaneously breathing patients, adequate compensation of tube resistance (i.e. with minimal overcompensation and minimal undercompensation) is best done by the ATC mode.
Comparative effect of amrinone, aminophylline and diltiazem on rat airway smooth muscle
Authors: Matsuda F. , Sugahara K. , Sugita M. , Sadohara T. , Kiyota T. , Terasaki H.
Published: March 2003

We investigated the effect of amrinone, a phosphodiesterase III inhibitor, on rat airway smooth muscle, and thereafter, compared its activity with aminophylline and diltiazem. Amrinone produced relaxation of the acetylcholine‐induced airway contraction in a dose‐related manner. This bronchodilatory activity of amrinone was similar to that of aminophylline, but smaller than that of diltiazem. The 50% relaxant effect (ED50) of amrinone, aminophylline and diltiazem were 3.6×10−4 M, 1.4×10−4 M and 1.4×10−5 M, respectively. Diltiazem was the most potent airway relaxant, and amrinone was less potent in these experiments. Taken together in its positive inotropic and chronotropic effects and anti‐inflammatory activity, however, amrinone could be beneficial for treatment of patients suffering from asthma or heart failure with cardiac asthma.
Anaphylactic reactions during induction of anaesthesia using rocuronium for muscle relaxation: A report including 3 cases
Authors: Heier T. , Guttormsen A. B.
Published: March 2003

Anaphylaxis during induction of anaesthesia is a dreaded complication with a mortality rate of 3–6%, most frequently associated with the use of muscle relaxants. Current knowledge on this matter is reviewed in relation to the presentation of 3 cases of anaphylaxis and bronchospasm associated with the use of the recently released nondepolarizing muscle relaxant rocuronium. Bronchospasm may be the sole sign of a serious drug reaction, triggered by precipitation of insoluble thiopental crystals when mixed with a muscle relaxant in the intravenous (iv) line. It is recommended that these drugs are administered via different injection ports. The hypotension requires immediate treatment with oxygen, epinephrine and large amounts of iv fluids. Epinephrine infusion may be needed for hours. It is recommended that serum tryptase is measured approximately 2 h after debut of the serious drug reaction. Allergy testing should be performed for all the drugs the patient was exposed to, 4–8 weeks after the incident, and due to cross‐reactivity, including all available muscle relaxants. Doctors are urged to inform their patients, and systematically register adverse drug reactions.
A comparison of anaesthesia using remifentanil combined with either isoflurane, enflurane or propofol in patients undergoing gynaecological laparoscopy, varicose vein or arthroscopic surgery
Authors: Chung F. , Mulier J.‐P. , Scholz J. , Breivik H. , Araujo M. , Hjelle K. , Upadhyaya B. , Haigh C.
Published: March 2003

Background: Anaesthesia comprising remifentanil plus isoflurane, enflurane or propofol was randomly evaluated in 285, 285 and 284 patients, respectively, undergoing short‐procedure surgery.

Methods: Anaesthesia was induced with propofol (0.5 mg · kg−1 and 10 mg · 10 s−1), and a remifentanil bolus (1 μg · kg−1) and infusion at 0.5 μg · g−1 · min−1. Five minutes after intubation, remifentanil infusion was halved and 0.5 MAC of isoflurane or enflurane, or propofol at 100 μg · kg−1 · min−1 were started and titrated for maintenance.

Results: Patient demography and anaesthesia duration were similar between the groups. Surgery was performed as daycases (52%) or inpatients (48%). The median times (5–7 min) to extubation and postoperative recovery were similar between the groups. Responses to tracheal intubation (15% vs 8%) and skin incision (13% vs 7%) were significantly greater in the total intravenous anaesthesia (TIVA) group (P<0.05). Fewer patients given remifentanil and isoflurane (21%) or enflurane (19%) experienced ≥1 intraoperative stress response compared to the TIVA group (28%) (P<0.05). Median times to qualification for and actual recovery room discharge were 0.5–0.6 h and 1.1–1.2 h, respectively. The most common remifentanil‐related symptoms were muscle rigidity (6–7%) at induction, hypotension (3–5%) and bradycardia (1–4%) intraoperatively and, shivering (6–7%), nausea and vomiting postoperatively. Nausea (7%) and vomiting (3%) were significantly lower with TIVA compared with inhaled anaesthetic groups (14–15% and 6–8%, respectively; P<0.05).

Conclusion:

Anaesthesia combining remifentanil with volatile hypnotics or TIVA with propofol was effective and well tolerated. Times of extubation, postanaesthesia recovery and recovery room discharge were rapid, consistent and similar for all three regimens.
Effects on the bispectral index during medium‐high dose fentanyl induction with or without propofol supplement
Authors: Barr G. , Anderson R. E. , Öwall A. , Jakobsson J. G.
Published: March 2003

Background: The search for a drug‐independent monitor to determine depth of anaesthesia and hypnosis continues. The bispectral analysis (BIS) of the EEG correlates well with the clinical dose–response of hypnotic drugs during induction, but the effect on BIS of an opiate induction, as for coronary bypass surgery, is not known.

Methods: Fourteen patients scheduled for elective coronary bypass surgery were studied. BIS was recorded during induction in 7 patients receiving 10 μg/kg fentanyl without any hypnotic agent and in 7 patients receiving 0.5 mg/kg propofol before the fentanyl dose.

Results: The effect of fentanyl was very variable both regarding BIS and clinical response. Five of the 7 patients that received only fentanyl lost their response to verbal command within 8 min. BIS values at loss of response varied between 45 and 94. One patient remained awake with BIS 43. All 7 patients receiving propofol before the fentanyl dose lost their response to verbal command within 5 min. BIS values at the time for loss of response varied between 78 and 98.

Conclusion: Loss of response to verbal command when a medium‐high dose of fentanyl is used for induction cannot be distinguished from wakefulness with adequate sensitivity by BIS. The current BIS algorithm seems not to accurately reflect the hypnotic effects of fentanyl.
Stability of an epidural analgesic solution containing adrenaline, bupivacaine and fentanyl
Authors: Kjønniksen I. , Brustugun J. , Niemi G. , Breivik H. , Anderssen E. , Klem W.
Published: March 2003

Background: A low dose solution of adrenaline 2 μg · ml−1, fentanyl 2 μg · ml−1 and bupivacaine 1 mg · ml−1 has been reported to give superior pain control when used for epidural analgesia after major surgery. The present paper describes the compounding and chemical stability of this triple‐component solution during storage and use.

Methods: Sterile triple‐component concentrates (11X) were diluted by the use of gas isolator technology to give ready‐to‐use infusion solutions. Eight solutions were analysed by reverse phase high‐performance liquid chromatography (HPLC) methods, and assays were performed on 1, 45, 90 and 180 days after storage at 2–8°C. After 180 days the solutions were subsequently stored at 22°C for four days before they were reanalysed. HPLC quantification of adrenaline was also performed on samples from solutions given to 28 different patients.

Results: The concentration of adrenaline and fentanyl decreased approximately 3.5% from 1 to 180 days at 4°C and four days at 22°C. The corresponding figure for bupivacaine was an apparent increase by 2.4% in concentration. No absorption to the polypropylene plastic bags of fentanyl and bupivacaine was detected. None of the 28 samples derived from used infusion bags contained less than 95% of the declared content of adrenaline.

Conclusions: The triple‐component epidural analgesic solution remained stable during six months of cold storage, followed by four days of storage at room temperature. No significant degradation of adrenaline was observed in infusion solutions returned from the wards.
Cutaneous sympathetic vasoconstrictor reflexes for the evaluation of interscalene brachial plexus block
Authors: Lehtipalo S. , Winsö O. , Koskinen L‐O. D. , Johansson G. , Biber B.
Published: March 2003

Background: Although signs of sympathetic blockade following interscalene brachial plexus block include Horner’s syndrome, increased skin temperature and vasodilatation, the degree of sympathetic blockade is not easily determined. The aim of this study was, therefore, to use activation of cutaneous finger pad vasoconstrictor reflexes for description and quantification of the degree of sympathetic blockade following unilateral interscalene brachial plexus block.

Methods: Eight patients scheduled for acromioplasty under general anesthesia were studied. An interscalene plexus catheter was inserted preoperatively on the side to be operated upon and used postoperatively for administration of bupivacaine, given as a bolus (1.25 mg kg−1) followed by a continuous infusion (0.25 mg kg−1 h−1). Skin blood flow (SBF) in the pad of the index finger was assessed by the laser Doppler technique, and regional skin vascular resistance (RVR) was calculated. The inspiratory gasp test (apnea at end‐inspiration) or a local heat provocation were used as provocations of the cutaneous microcirculation.

Results: Interscalene brachial plexus block increased SBF and decreased RVR at rest, and produced satisfactory sensory and motor block. The inspiratory gasp test decreased SBF and increased RVR in the unblocked arm, while the opposite, increased SBF and decreased RVR, were observed during local heat provocation. In the blocked arm, these gasp‐induced cutaneous vasoconstrictor and heat‐induced vasodilator responses were attenuated.

Conclusions: Interscalene brachial plexus block reduces regional sympathetic nervous activity, illustrated by increases in skin blood flow, skin temperature and attenuated vasoconstrictor responses to an inspiratory gasp. The inspiratory gasp vasoconstrictive response is a powerful and sensitive indicator for monitoring the sympathetic blockade following interscalene brachial plexus block.
Effects of ketamine on formalin‐induced activity in the spinal dorsal horn of spinal cord‐transected cats: differences in response to intravenous ketamine administered before and after formalin
Authors: Nagasaka H. , Nakamura S. , Mizumoto Y. , Sato I.
Published: March 2003

Background: Although formalin has been widely used as an algesic substance in rodent studies, the unique biphasic effect seen in rats is not present in humans. Humans, like cats, have a monophasic behavioral response to formalin injection. Electrophysiologically, spinal dorsal horn neurons in cats also have what could be considered a monophasic response after the initial burst of activity following formalin injection. Although several studies of the effects of ketamine on formalin responses have been carried out in rodents, we are unaware of similar studies in cats. We hypothesize that such species differences may explain observed differences in preemptive analgesic effects. Therefore, we examined the effects of ketamine on activity of spinal wide dynamic range (WDR) neurons evoked by formalin injection in cats.

Methods: We investigated in cats the effect of ketamine on the activity of WDR neurons in the spinal dorsal horn that was evoked by formalin. In addition, we studied the effects of pre‐ and post‐administration of ketamine on the maintained phase of the formalin response. Each dose was a subanesthetic, anesthetic or high anesthetic dose (3.0 mg · kg−1, 10 mg · kg−1, and 30 mg · kg−1).

Results: Intravenously administered ketamine produced a dose‐dependent depression of evoked activity that was significantly greater when the drug was administered before formalin.

Conclusions: In spite of the species differences in responses to formalin, there still appears to be a clear preemptive effect of ketamine in the cat. Species differences may not explain apparent differences between human and animal preemptive analgesia.
Effects of propofol on desipramine‐sensitive [3H]‐noradrenaline uptake kinetics in rat femoral artery
Authors: Sandström K. , Wallerstedt S. M. , Törnebrandt K. , Bodelsson M.
Published: March 2003

Background: The intravenous anaesthetic propofol inhibits the neuronal uptake of noradrenaline (uptake1) from the vascular sympathetic neuromuscular junction, resulting in an enhancement of the sympathetic neurotransmission. This could be important for maintenance of blood pressure during propofol anaesthesia. The aim of the present study was to determine how propofol influences the kinetics of uptake1.

Methods: Isolated segments of rat femoral arteries were incubated with [3H]‐noradrenaline in the presence or absence of propofol and the radioactivity taken up was measured in a scintillation counter. The uptake1 inhibitor, desipramine, was used to delineate the specific neuronal uptake.

Results: Desipramine and 10 μM propofol significantly reduced the uptake in segments incubated with 0.1 μM [3H]‐noradrenaline. Propofol at 1 μM and 100 μM did not affect the uptake. Non‐linear regression analysis of specific uptake yielded Km 0.50 μM, Vmax 1.6 pmol mg−1 15 min−1 and Hill coefficient 1.1. Propofol (1–10 μM) increased the Km value and propofol (10–100 μM) increased the Vmax value concentration‐dependently, while the Hill coefficient was not affected.

Conclusion: Propofol seems to have a biphasic effect on the uptake of noradrenaline in the vascular sympathetic neuromuscular junction. At lower propofol concentrations there is a decrease in the affinity of the noradrenaline transporters. The resulting uptake inhibition is counteracted at higher propofol concentrations by an increase in the efficacy of the uptake.
Adenosine and cardioprotection during ischaemia and reperfusion – an overview
Authors: Sommerschild H. T. , Kirkebøen K. A.
Published: March 2003

Adenosine is a local hormone, with numerous tissue‐specific biological functions. In the myocardium, adenosine is released in small amounts at constant basal rate during normoxia. During ischaemia the production of adenosine increases several fold due to breakdown of adenosine triphosphate (ATP). Increased production of adenosine causes coronary vasodilatation. Thus, adenosine couples myocardial metabolism and flow during ischaemia and is called a homeostatic or “retaliatory metabolite”. Furthermore, adenosine has electrophysiological effects in supraventricular tissue, causing a decrease in heart rate. In 1985 it was discovered that adenosine also exerts cardioprotective effects directly on cardiomyocytes. The aim of this review is to give an overview of the role of adenosine as a directly cytoprotective agent during myocardial ischaemia and reperfusion. We will focus on its effects on the myocytes, elicited by stimulation of adenosine receptors in sarcolemma, which triggers intracellular signalling systems. We will also address the new aspect that adenosine can influence regulation of gene expression. There is evidence that the myocardium is capable of endogenous adaptation in response to ischaemia, namely “hibernation” and early and late phases of “preconditioning”. Endogenous substances produced during ischaemia probably trigger these responses. We will discuss the role of adenosine in these different settings. Adenosine can be given exogenously through intravasal routes; however, this review will also focus on the effects of endogenously produced adenosine. We will discuss pharmacological ways to increase endogenous levels of adenosine, and the effects of such interventions during ischaemia and reperfusion. Finally, we will review results from studies in humans together with relevant experimental studies, and indicate potential therapeutic implications of adenosine.
Preoperative ropivacaine infiltration in breast surgery
Authors: Johansson A. , Axelson J. , Ingvar C. , Luttropp H.‐H. , Lundberg J.
Published: March 2003

Purpose:

The aim of the study was to investigate whether preoperative infiltration with ropivacaine in conjunction with breast surgery improves postoperative pain management and attenuates postoperative nausea and vomiting.

Method:

Prospective, randomised, double‐blind study, including 60 healthy women (ASA 1–2) allocated to one of two groups. Thirty patients were given 0.3 ml/kg saline in the operating field before surgery. Another 30 patients received a similar volume of ropivacaine 3.75 mg/ml. A visual analogue scale (0–100 mm) was used for evaluation of postoperative pain, nausea and vomiting. If the score was more than 30 mm at rest, the patients were given ketobemidone i.v. as treatment for postoperative pain, and dixyrazine i.v. against nausea and vomiting. The intra‐ and postoperative analgesic requirements and postoperative nausea and vomiting were registered.

Results: The intraoperative fentanyl consumption was similar in the saline group 81±22 μg vs 76±28 μg; (ns) in the ropivacaine group. The postoperative 24‐h ketobemidone consumption was also similar to those treated with ropivacaine (4.2±2.6 mg vs 4.2±4.3 mg; ns). Postoperative nausea and vomiting (PONV) occurred with similar frequencies in both groups. The 24‐h dixyrazine consumption was the same in the two groups (2.1±2.7 mg in the saline group compared to 2.4±2.8 mg in the ropivacaine group; ns). After 6 h recovery, 41% of all patients had experienced nausea and 20% vomiting.

Conclusion: We found no differences in postoperative pain management between 3.75 mg/ml ropivacaine and saline wound infiltration before breast surgery. The data show similar postoperative needs of analgesics and antiemetics with a similar frequency of PONV.
Pharmacokinetics of 0.2% ropivacaine and 0.2% bupivacaine following caudal blocks in children
Authors: Ala‐Kokko T. I. , Partanen A. , Karinen J. , Kiviluoma K. , Alahuhta S.
Published: March 2003

Background: Ropivacaine is the first S‐enantiomer aminoamide local anaesthetic in clinical use, and has been found to be less toxic than bupivacaine. Caudal ropivacine has been shown to cause less motor blockade and longer duration of analgesia in the postoperative period than bupivacaine in children. Plasma levels of ropivacaine and bupivacaine have not been previously compared in children. This study was undertaken to compare the total venous plasma concentrations of similar doses of ropivacaine and bupivacaine following caudal administration.

Methods: Blood samples were obtained to determine the total venous plasma levels of the used local anaesthetic in 30 children, aged 2.3–8.7 years, ASA I, given 1 ml · kg−1 of either 0.2% ropivacaine or 0.2% bupivacaine in a prospective, randomised manner.

Results: There were no differences in the individual peak plasma concentrations achieved. Time to the measured peak plasma concentration was significantly shorter in the bupivacaine group. The plasma concentrations of bupivacaine were significantly lower than for ropivacaine at 60, 90 and 120 min after the block.

Conclusion: Absorption and tissue distribution of ropivacaine is slower than for bupivacaine following caudal administration in children.
Coagulation effects of a recently developed hydroxyethyl starch (HES 130/0.4) compared to hydroxyethyl starches with higher molecular weight
Authors: Entholzner E. K. , Mielke L. L. , Calatzis A. N. , Feyh J. , Hipp R. , Hargasser S. R.
Published: March 2003

Background: Hydroxyethyl starches (HES) are known to interfere with blood coagulation according to molecular weight, the degree of substitution and the C2/C6 ratio. A recently developed low molecular hydroxyethyl starch (HES 130/0.4) was designed to reduce the blood compromising potency.

Methods: In this study, effects of a 30% in vitro haemodilution with the new HES preparation (HES 130/0.4) in comparison to HES 200/0.5, HES 450/0.7 and sodium chloride solution were investigated using intrinsic and extrinsic activated thrombelastography (TEG) and plasmatic coagulation tests.

Results: Whereas plasmatic tests revealed no prolongation of coagulation by HES in comparison to sodium chloride, the TEG variables clotting time, clot formation time and maximal clot firmness showed a significant (P<0.05) inhibition by all the HES preparations. The inhibition was most pronounced in HES 450 (P<0.05 vs HES 130) while HES 130 did not show a statistically significant difference in extrinsic activated maximal clot firmness when compared to sodium chloride.

Conclusion: These in vitro results demonstrate that hydroxythyl starches especially compromise clot polymerisation. The new preparation HES 130/0.4 seems to inhibit platelet function to a lesser extent than hydroxyethyl starch preparations with a higher molecular weight and degree of substitution.
Influence of opioids on the vascular tone of isolated porcine coronary artery segments
Authors: Klockgether‐Radke A. P. , Gravemann J. , Kettler D. , Hellige G.
Published: March 2003

Background: It was the aim of this study to elucidate the influence of opioids on coronary vascular tone using the model of isolated porcine coronary artery segments.

Methods: We studied the effects of fentanyl (0.01, 0.1, 1.0 μg ml−1), alfentanil (0.1, 1.0, 10 μg ml−1), and sufentanil (0.01, 0.1, 1.0 μg ml−1) on the contractile response to three vasoconstrictors, acetylcholine, histamine and serotonin.

Results: Fentanyl (0.1, 1.0 μg ml−1) dose‐dependently attenuated the contractile response to acetylcholine, but not to histamine and serotonin. There were no differences in fentanyl's vasorelaxing potency between rings with intact and denuded endothelium. Alfentanil and sufentanil did not exert any significant influence on any of the vasoconstrictors tested.

Conclusion: It is concluded that, in isolated porcine coronary artery rings, fentanyl at high concentrations has an attenuating effect on acetylcholine‐induced contractions, which is independent of endothelial function, whereas alfentanil and sufentanil do not influence coronary vascular tone.
Hemidiaphragmatic paresis after interscalene supplementation of insufficient axillary block with 3 mL of 2% mepivacaine
Authors: Koscielniak‐Nielsen Z. J.
Published: March 2003

Breathing difficulty, agitation, and confusion developed in a 55‐year‐old male, ASA classification group III with a non‐small‐cell lung cancer 10 min after interscalene supplementation of insufficient axillary block with 3 mL of 2% mepivacaine with adrenaline 5 μg mL−1. After administration of thiopentone and suxamethonium the patient's trachea was intubated and the lungs were ventilated with oxygen‐enriched air. The block was successful and surgery was conducted as scheduled. Radiographic monitoring of the lungs at the end of operation showed ipsilateral elevation of the diaphragm with reduced respiratory excursions. Postoperatively, the patient was somnolent and hypercapnic, but maintained satisfactory oxygenation while breathing spontaneously and was extubated. Both the temporal relationship of events and the regression of all symptoms within three hours suggest that 3 mL of mepivacaine with adrenaline injected into the interscalene space blocked the phrenic nerve and compromised diaphragmatic function, which precipitated the respiratory failure.
Endogenous morphine is produced in response to cardiopulmonary bypass in neonatal pigs
Authors: Brix‐Christensen V. , Goumon Y. , TØnnesen E. , Chew M. , Bilfinger T. , Stefano G. B.
Published: March 2003

Background: Cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response. Endogenous morphine production has previously been demonstrated in humans after cardiac surgery with CPB. It has been hypothesized that morphine plays a role as an anti‐inflammatory mediator in the systemic inflammatory response. The aim of this study was to investigate if the CPB procedure in itself elicits an endogenous morphine production in neonatal pigs.

Methods: Endogenous morphine production was measured in arterial blood in piglets exposed to sternotomy alone (sham group, n=10) or sternotomy and CPB (n=10). Blood samples were obtained immediately after the induction of anaesthesia, at the end of CPB and 4 h later. Morphine in arterial blood was detected by radioimmunoassay and confirmed by gas chromatography mass spectrometry.

Results: Animals undergoing CPB showed detectable endogenous morphine concentrations immediately after CPB, with increased concentrations postoperatively. There was no measurable morphine production in the sham operated pigs.

Conclusion: The CPB procedures elicits an endogenous morphine production in neonatal pigs. This morphine response is analogous to the previously demonstrated response in patients subjected to cardiac surgery and CPB.
Surgical stress induces acute coronary release of tissue‐type plasminogen activator in the pig
Authors: Österlund B. , Holmgren A. , HÄggmark S. , Jern C. , Johansson G. , Seeman‐Lodding H. , Biber B.
Published: March 2003

Background: Tissue‐type plasminogen activator (t‐PA) is an endothelium derived key enzyme in the initiation of endogenous fibrinolysis. Acute regulated release of active t‐PA occurs within minutes in response to threatening thrombotic vessel occlusion. The aim of this study was to investigate the impact of surgical stimulation on the kinetics of t‐PA release in the coronary vascular bed in the pig.

Methods: In anaesthetised pigs (n=16), arterio‐venous concentration gradients of t‐PA, and plasma flows (retrograde thermodilution) were obtained across the coronary vascular bed before (control) and at 1, 3, 5 and 10 min after sternotomy.

Results: At control, no significant coronary net flux (release or uptake) of t‐PA was observed, while sternotomy induced a rapid net release of total t‐PA (132.6 ng · min−1), with an associated increase in active t‐PA (93.6 ng · min−1). This response, evident already after 1 min, showed a peak at 5 min and returned towards baseline levels within 10 min. No concurrent alterations in aortic levels of active t‐PA were found and haemodynamic variables were unaltered.

Conclusion: The rapidly increasing and transient net coronary release of t‐PA after sternotomy suggests that the endothelium actively promotes local endogenous fibrinolysis during surgery. Such events could reflect a dynamic responsiveness to protect the coronary circulation during stress.
Stroke following appendectomy under general anesthesia in a patient with basilar impression
Authors: Zotter H. , Zenz W. , Gallistl S. , ZÖhrer B. , Lindbichler F.
Published: March 2003

We report a boy who developed a vertebral stroke immediately after an appendectomy. Basilar impression was diagnosed eight years after this event when skull roentgenograms revealed basilar impression with high standing tip of the odontoid. We speculate that muscle relaxation and cervical hyperextension during intubation in the presence of basilar impression resulted in vertebral artery dissection and stroke. We suggest that patients with vertebral stroke and no obvious risk factors should be evaluated for the presence of malformations of the craniovertebral junction to be able to take precautions against excessive neck movement during intubation.
Risk factors for preoperative anxiety in adults
Authors: Caumo W. , Schmidt A. P. , Schneider C. N. , Bergmann J. , Iwamoto C. W. , Bandeira D. , Ferreira M. B. C.
Published: March 2003

Background: Patients who undergo surgery experience acute psychological distress in the preoperative period. The objective of this study was to identify and quantify the effect of risk factors for preoperative anxiety in adults.

Methods: A cross‐sectional study was performed with 592 inpatients scheduled for elective surgery. Age ranged from 18 to 60 years (ASA physical status I–III). Demographic information was collected using a structured questionnaire. The measuring instruments were a visual analog scale, the State‐Trait Anxiety Inventory, the Montgomery‐Äsberg Depression Rating Scale, the WHO Self‐Reporting Questionnaire‐20, and the future self‐perception questionnaire. Multivariate conditional regression modeling was used to control confounding factors and to determine independent predictors of preoperative anxiety, taking into account the hierarchical relationship between risk factors.

Results: High preoperative anxiety was associated with history of cancer (odds ratio (OR)=2.26) and smoking (OR=7.47), psychiatric disorders (OR=5.93), negative future perception (OR=2.30), moderate to intense depressive symptoms (3.22), high trait‐anxiety (3.83), moderate to intense pain (2.12), medium surgery (OR=1.52), female gender (OR=2.0), ASA category III (OR=3.41), up to 12 years of education (OR=1.36), and more than 12 years of education (OR=1.68). Previous surgery (OR=0.61) was associated with lower risk for preoperative state‐anxiety.

Conclusions: History of cancer and smoking, psychiatric disorders, negative future perception, moderate to intense depressive symptoms, high trait‐anxiety, moderate to intense pain, medium surgery, female gender, ASA category III, up to 12 years of education and more than 12 years of education constituted independent risk factors for preoperative state‐anxiety. Previous surgery reduced the risk for preoperative anxiety.
Recovery profile and side effects of remifentanil‐based anaesthesia with desflurane or propofol for laparoscopic cholecystectomy
Authors: Grundmann U. , Silomon M. , Bach F. , Becker S. , Bauer M. , Larsen B. , Kleinschmidt S.
Published: March 2003

Background: Nitrous oxide (N2O) has been suggested to contribute to bowel distension, resulting in worsened operating conditions for laparoscopic surgery, and to increase incidence of postoperative nausea and vomiting. Therefore, our objective was to assess the feasibility of two remifentanil‐based anaesthetic regimens free from N2O with special regard to recovery profile, postoperative analgesic demand and side effects in patients undergoing laparoscopic cholecystectomy.

Methods: Fifty patients (ASA I–II, 23–65 yr) were randomly assigned to receive remifentanil‐based anaesthesia in conjunction with propofol (group R/P) or desflurane (group R/D). After standardised induction of anaesthesia, analgesia was continued with remifentanil in all patients. For maintenance of hypnosis, propofol or desflurane were used in concentrations to ensure loss of consciousness, lack of awareness, and maintenance of heart rate and blood pressure within ±25% of initial values. At the end of surgery all anaesthetics were discontinued without tapering and early emergence and recovery were recorded. Pain scores were assessed by using a visual analogue scale. Patient‐controlled analgesia with i.v. piritramide was used for treatment of postoperative pain and recorded for 90 min in the postanaesthesia care unit (PACU). In addition, side effects were noted.

Results: Early emergence from anaesthesia did not differ between the groups. In group R/P, time to eye opening, spontaneous respiration and extubation was 4.4±2.9 min, 5.2±3.4 min and 5.5±3.3 min respectively, compared with 4.7±2.7 min, 5.3±2.4 min and 5.7±2.5 min in group R/D. While pain scores did not differ between both groups on admission to the PACU, patients receiving desflurane required more i.v. piritramide as compared to those receiving propofol, 22.0±6.5 mg and 17.9±7.0 mg, respectively (P<0.05). Nausea was less frequent after propofol (16% vs. 48%, P<0.05).

Conclusion: In patients undergoing laparoscopic cholecystectomy, remifentanil‐based anaesthetic regimens in conjunction with propofol or desflurane are suitable and allow for rapid recovery from anaesthesia. However, the use of propofol results in less postoperative analgesic consumption and nausea as compared to desflurane.
Early detection of increased tumour necrosis factor alpha (TNFα) and soluble TNF receptor protein plasma levels after trauma reveals associations with the clinical course
Authors: Spielmann S. , Kerner T. , Ahlers O. , Keh D. , Gerlach M. , Gerlach H.
Published: March 2003

Background: The inflammatory response after trauma includes tumour necrosis factor alpha (TNFα) as pro‐inflammatory cytokine. Furthermore, both soluble TNF receptor proteins (sTNF‐R1 and sTNF‐R2) were described to influence the post‐traumatic inflammatory response and organ dysfunction.

Method:

From 47 trauma patients, blood samples were obtained at the scene of accident, at hospital admission, after 4 h, 12 h, and 24 h, and daily until day 6. Plasma levels of TNFα, sTNF‐R1 and sTNF‐R2 were measured by enzyme immunoassay (EIA) and analysed comparing clinical parameters such as injury scores (ISS, AIS), development of multiple organ dysfunction syndrome (MODS) and/or systemic inflammatory response syndrome (SIRS), and outcome.

Results: Significant changes were observed in a time‐dependent manner: TNFα and soluble TNF receptor levels were elevated compared to values of healthy persons. At 4 h after trauma, TNFα and sTNF‐R2 showed an increase from initial values, which continued during the entire observation period. Severe trauma led to enhanced sTNF‐R1 levels on scene and on hospital admission. Development of SIRS along with elevated sTNFR1 began on scene and was present on admission, with increased sTNF‐R2 from day 1 to day 4. MODS (until day 6) was preceded by increased sTNF‐R2 levels on admission and up to 4 h after trauma. Outcome was associated neither with TNFα nor with soluble TNF receptor levels.

Conclusion: Thus, in trauma patients, early post‐traumatic MODS and SIRS coincide with increased levels of TNFα and TNF receptor proteins, revealing different, time‐dependent changes. Hence, detection of TNFα and soluble TNF receptor proteins after trauma should pay regard to the time point of sampling.
Blood viscosity, hemodynamics and vascular hindrance in a rat model of acute controlled bleeding and volume restitution with blood or Haemaccel
Authors: Hilzenrat N. , Arish A. , Yaari A. , Almog Y. , Sikuler E.
Published: March 2003

Background:

Hemorrhage and volume restitution with commercially available solutions is followed by reduced blood viscosity. Consequent hemodynamic changes may arise not only from the reduced viscosity itself but also from changes in vascular geometry induced by autoregulation processes. Vascular hindrance reflects the contribution of vascular geometry to flow. Our aim was to explore the possible effects of blood volume restitution with Haemaccel or blood, on regional blood flow and vascular geometry.

Methods: Under ketamine anesthesia, blood was withdrawn at a rate of 0.3 ml/min for 15 min followed by 15 min of stabilization. The shed blood or Haemaccel was infused at the same rate and volume as used for withdrawal. Hemodynamic measurements were performed using radioactive microspheres. Blood viscosity was measured with an Ostwald viscometer. Vascular hindrance was calculated as the resistance/viscosity ratio.

Results: Volume replacement with Haemaccel (n=10), compared to blood (n=10), was followed by increased cardiac output and portal venous inflow (37.1±9.0 and 3.1±0.5 vs 25.9±6.8 and 2.2±0.9 ml · min−1 · 100 g bw−1, respectively; P<0.05), decreased viscosity (2.8±1.3 vs 3.7±1.3, respectively; P<0.01) and decreased peripheral and splanchnic arteriolar resistance (3.8±1.1 and 40.9±7.6 vs 5.2±1.7 and 61.1±29.5 mmHg · ml−1 · min · 100 g bw, respectively; P<0.05). No significant differences between the groups were observed in vascular hindrance and cardiac output distribution.

Conclusion: Volume replacement with Haemaccel, compared to blood, induced increase in systemic and splanchnic blood flows, reflecting mainly changes in viscosity and not in blood vessel geometry. These results suggest no significant difference in overall activation of autoregulation process between volume restitution with blood or Haemaccel.
The effect of chronic cocaine administration on hemodynamic stability and neurohumoral mediators during isoflurane anesthesia and shock in rats
Authors: Mets B. , Pantuck C. B. , Diaz J. , Soo E.
Published: March 2003

Background: The aim of this investigation was to determine whether chronic cocaine administration altered endogenous vasoconstrictor secretion in response to hypotension from isoflurane anesthesia and blood loss in rats.

Methods: Rats received continuous intravenous infusions of saline (n=11), or cocaine 6 mg kg−1 d−1 (n=13) or 18 mg kg−1 d−1 (n=12) for 13 days. On day 14, rats were anesthetized with intraperitoneal ketamine and xylazine and a femoral artery catheter and a tracheotomy performed to allow lung ventilation (PaCO2, 30–40 mmHg). After baseline parameters were noted, isoflurane was introduced to end‐tidal concentrations of 0.7% for 10 min (1/2 MAC), 1.4% for 10 min (MAC) and again 0.7% for 10 min (1/2 MAC‐2) when 5 ml of blood was withdrawn (SHOCK). Blood samples were drawn to assess arterial blood gas indices at various time points as well as plasma epinephrine, angiotensin II and vasopressin at MAC, 1/2 MAC‐2 and SHOCK.

Results: Rats administered cocaine had higher oxygen extraction, required higher minute ventilation and had lower PaO2 values than rats administered saline despite similar body temperatures and hematocrits. Isoflurane administration resulted in significant dose dependent but similar blood pressure decreases in all study groups. Plasma epinephrine, angiotensin II and vasopressin concentrations were not different in saline or cocaine treated animals at any time point.

Conclusion: These data suggest that chronic cocaine treatment in rats does not impair endogenous vasoconstrictor secretion nor alter the heart rate and blood pressure response to isoflurane and blood loss.
Management of postoperative pain in Spain
Authors: Puig M. M. , Montes A. , Marrugat J.
Published: March 2003

Background: The management of postoperative pain is suboptimal world‐wide. This survey was carried out to determine current management in Spanish hospitals.

Methods: Spanish hospitals were divided into two groups: <200 beds (n=346) and >200 beds (n=186). A structured questionnaire was mailed to the heads of the anaesthesiology services of a random sample of 150 of hospitals of <200 beds, and all larger hospitals.

Results: Only 19% of hospitals with <200 beds responded and further analysis of this group was not possible; 53% of hospitals with >200 beds responded. In this sample (>200 beds), 45% of patients receive information on postoperative pain, given by the anaesthesiologist in 78% of cases. Over 70% of the hospitals do not have an acute pain unit and responsibility for postoperative pain lies with the anaesthesiology team in 71%, with the surgical team in 40% and with nursing in 33%, with an overlap of pain caretakers. Pain is measured on the surgical wards in 36% and recorded with the vital signs in 34%. On post‐anaesthetic recovery wards, analgesia is most frequently given by intravenous (83%), epidural (78%) and continuous intravenous (66%) administration. On surgical wards, the most frequent routes that are available are epidural (72%), intravenous (69%) and intramuscular (58%). Only 28% of the anaesthesiology services are satisfied with the pain treatment carried out in their hospitals. No significant differences on postoperative pain management were observed between teaching and non‐teaching institutions.

Conclusion: The survey shows that the management of postoperative pain in hospitals with >200 beds in Spain is suboptimal and this is associated with dissatisfaction among many anaesthesiologists.