bluuebunny/crossref_metadata_2025 huggingface dataset:
Continuous cardiac output measurements in the perioperative period
Authors: Jakobsen C‐J. , Melsen N. C. , Andresen E. B.
Published: January 2009

Management of critically ill patients is based on knowledge of fundamental physiologic variables. Automatized and continuous measurement of these variables is preferable. A new system based upon the thermodilution method has been developed to measure cardiac output automatically and continuously. We evaluated the system in the potentially unstable perioperative period with possible great and rapid changes in cardiac output. Twenty patients, scheduled for open heart or abdominal aortic aneurysm surgery, were included in the study, which was approved by the local ethical committee. The patients were monitored up to 30 hours. At random intervals five, iced, bolus thermodilution cardiac output (BCO) determinations were made and compared to the continuous cardiac output measurements (CCO). Two hundred and thirty‐one pairs of data were obtained. The cardiac outputs ranged from 2.5–14.9 1‐min‐1. The absolute bias was 0.31 1‐min‐1 (95% limits of agreement—1.4 1‐min‐1 to 2.0 1‐min‐1). The mean relative error was 4.7% with a standard deviation of the relative error of 15.4%. The linear regression was represented by: CCO= 1,1352‐BCO—0.36. The correlation coefficient R was 0.90 (P<0.001). In conclusion, the CCO measurement technique is a promising clinical method. The method is straightforward, requires no calibration, is independent of vascular geometry and measures with its limitations volumetric flow. Finally automatic and continuous patient monitoring provides more information and has potential to reveal previously undetected haemodynamic events.
Neurochemical evidence that [Ca2+]oantagonizes the effect of neomycin on acetylcholine release from mouse hemidiaphragm preparation: An attempt to assess the margin of safety
Authors: Chaudhry I. A. , Nitahara K. , Nagashima H. , Vizi E. S.
Published: January 2009

Although the neuromuscular junction is the most thoroughly studied synapse of any type and has become the model of our understanding of synaptic transmission, some questions remain unanswered; e.g. there has been no direct assessment of the size of margin of safety.

In this study the [Ca2+]o‐dependent, quantally released acetylcholine measured by a neurochemical method, and the contraction of the mouse hemidiaphragm in response to phrenic nerve stimulation were recorded, and the effect of neomycin was studied.

It was found that a much higher concentration of neomycin was needed to depress contractions, than to reduce acetylcholine release to the same extent, and that there was an inverse correlation between [Ca2+]oand the inhibitory effect of neomycin on acetylcholine release. Ninety percent of the release of acetylcholine had to be reduced by neomycin before any reduction in muscle responses could be seen. This indicates that the margin of safety is about 10.

In conclusion, at the neuromuscular junction any reduction in ACh release, whatever the mechanism, first produces a reduction in the margin of safety. The nondepolarizing neuromuscular blocking agents block primarily the nicotinic receptors located on the postjunctional site. Many receptors have to be blocked before a reduction of muscle response is observed. This is probably the reason why unexpected clinical problems (e.g. recurarization) have been described when a patient has been treated with antibiotics, even though the dose of muscle relaxant injected was relatively low.
Response to single twitch or single burst stimulation of the ulnar nerve as predictive guide for intubating conditions
Authors: Helbo‐Hansen H. S. , Jensen B. , Nørreslet J. , Kirkegaard‐Nielsen H. , Haas I. M. de
Published: January 2009

Disappearance of response to single twitch stimulation (STS) or train‐of‐four stimulation (TOF) of the ulnar nerve is insufficient as predictive guide for intubating conditions during onset of non‐depolarizing neuromuscular block. Double burst stimulation (DBS) appears to be a more reliable indicator of the optimal time for intubation. In the present study, the disappearance of tactile detectable response to 0.1 Hz single twitch stimulation (STS) of the ulnar nerve was compared with disappearance of response to 0.1 Hz single burst stimulation (three stimuli at 50 Hz=SBS) as predictor for optimal intubating conditions during onset of block induced by 0.08 mg . kg‐1 of vecuronium in 100 patients under light general anaesthesia where thiopentone was used as the sole anaesthetic. Intubation was performed immediately after disappearance of the twitch response. Likewise 0.05 Hz STS and 0.05 Hz SBS stimulation were compared under identical circumstances in another 100 patients. Intubating conditions were unacceptable in 10%, 14%, 8% and 10% of the patients in the 0.1 Hz STS, 0.1 Hz SBS, 0.05 Hz STS and 0.05 Hz SBS groups, respectively. There were no significant differences between the groups. In conclusion, neither absence of response to STS stimulation nor absence of response to SBS stimulation of the ulnar nerve at either 0.1 Hz or 0.05 Hz frequency does guarantee acceptable intubating conditions during onset of neuromuscular block induced by vecuronium 0.08 mg . kg‐1 when thiopentone is used as the sole anaesthetic.
Interstitial fluid volume during cardiac surgery measured by means of a non‐invasive conductivity technique
Authors: Olthof C. G. , Jansen P. G. M. , de Vries J. P. P. M. , Kouw P. M. , Eijsman L. , de Lange J. J. , de Vries P. M. J. M.
Published: January 2009

Fluid accumulation in the interstitium is frequently found after cardiac surgery. In extreme this can lead to pulmonary and myocardial oedema. The origin of this accumulation is not exactly known and may be twofold. It is probably a combination of the noninfectious whole body inflammatory response and a change in Starling forces due to a decrease in colloid osmotic pressure (COP) which is caused by the primed extracorporeal circuit. To study the changes in interstitial fluid volume (ISFV) a non‐invasive conductivity technique was used. The relationship between temperature and conductivity was first investigated in vitro. A linear relationship was found between conductivity and different saline solutions and temperature. From the in vitro experiments it can be concluded that temperature corrected conductivity does not depend on haematocrit. After the in vitro experiments eleven patients undergoing cardiac surgery were studied. During the first minutes of cardiopulmonary bypass (CPB) a steep significant decrease in COP to 61.4±6.9% (from 19.6±1.1 to 12.0±1.2 mmHg), and a rise in ISFV to 105.5±2.8% (from 12.3±1.4 mS to 14.0±1.3 mS) was noticed. After this decrease COP increased significantly, till the end of the operation, but did not reach the pre‐operative level. An increase in ISFV was noticed till the rewarming point. After this point no significant change in ISFV was noticed. Furthermore, a significant correlation was found between the fluid balance and the ISFV increase at the start, at the end of CPB, and at the end of the operation. From the in vivo experiments it can be concluded that the non‐invasive conductivity technique in a valuable acquisition for the investigation of ISFV changes during cardiac surgery. It shows that the changes in ISFV are mainly disturbed during the first part of CPB probably due to a marked decrease in COP.
Pulmonary sympathetic denervation does not increase airway resistance in patients with chronic obstructive pulmonary disease (COPD)
Authors: Groeben H. , Schwalen A. , Irsfeld S. , Lipfert P. , Hopf H.‐B.
Published: January 2009

Whether or not neural blockade of pulmonary sympathetic innervation is of relevance for airway resistance in patients with chronic obstructive pulmonary disease (COPD) is unknown. Accordingly we evaluated airway resistance during sympathetic blockade by high thoracic epidural anaesthesia in patients with COPD. Before and 45 min after thoracic epidural injection of bupivacaine 0.75% (6–8 ml; n=10) total respiratory resistance (oscillometry, Ros), vital capacity (VC), forced expiratory vital capacity in 1 s (FEV1, [% VC]), functional residual capacity (FRC; helium dilution method), and arterial blood gases were measured. Three additional patients received bupivacaine intravenously (1.2 mg . min‐1 for 45 min), another three received saline epidurally. Sensory blockade covered segment C5 through T8. As an indicator of widespread sympathetic blockade including the lungs, skin temperature increased significantly on thumb and little toe. Despite pulmonary sympathetic denervation Ros, FEV1, and FRC remained unchanged, while VC decreased slightly, probably due to intercostal muscle blockade. Blood gases remained constant. Neither intravenous bupivacaine nor epidural saline evoked directional changes. Since, in contrast to β‐adre‐noceptor blockade, pulmonary sympathetic denervation did not increase airway resistance in patients with COPD, neural sympathetic blockade seems to be of no relevance for airway resistance in these patients.
Is the pencil point spinal needle a better choice in younger patients? A comparison of 24G Sprotte with 27 G Quincke needles in an unselected group of general surgical patients below 46 years of age
Authors: Brattebø G. , Wisborg T. , Rodt S. Å. , Røste I.
Published: January 2009

Reports have indicated that there are less postoperative complaints after the use of pencil pointed spinal needles. We compared a 24G Sprotte needle with a 27G Quincke needle in a randomised study of 200 healthy patients (49% females), aged 15–46 years. Four patients (2%) reported postdural puncture heActache, three with the 24G Sprotte needle and one with the 27G Quincke needle. Thirteen patients (7%) suffered with nonspecific heActache, with no significant difference betwen the two groups. Of the 57 (29%) who reported backpain, a significantly higher proportion had received spinal anaesthesia with the Sprotte needle (OR=2.06). There was a significantly higher incidence of insufficient blocks after dural puncture with the Sprotte needle. Ease of needle insertion and number of puncture attempts was the same for both needle types.
A prospective survey of postoperative nausea and vomiting with special regard to incidence and relations to patient characteristics, anesthetic routines and surgical procedures
Authors: Larsson S. , Lundberg D.
Published: January 2009

We performed a prospective study on 421 patients subjected to routine general‐, orthopaedic‐, urologic‐, gynecological and paediatric surgery to estimate the current incidences of nausea and vomiting during the first 24 hours after surgery.

The overall incidences of postoperative nausea or vomiting were 17% and 28%, respectively. Postoperative emetic symptoms were not related to age in adults. Women had more often emetic symptoms than men (P<0.01). In general, opiate premedication was more frequently associated with postoperative nausea and vomiting than benzodiazepines (P<0.01), but in otherwise comparable subgroups of patients undergoing major surgery, this difference was not confirmed. Balanced general anaesthesia caused more nausea (23%) and vomiting (53%) than face‐mask anaesthesia (13% and 15%, respectively) or regional blocks (12% and 7%, respectively) (P<0.001). There was a positive correlation between the duration of anaesthesia and the incidence of postoperative emetic symptoms (P<0.001). The incidences of postoperative nausea and vomiting after abdominal surgery were 23% and 58% respectively. Corresponding figures for orthopaedic surgery were 25% and 34%, other kinds of extra‐abdominal surgery 18% and 32% and for laparoscopy 21% and 25%. After minor gynecological‐, urological‐and paediatric surgery the incidences were less than 20%.

In conclusion female gender, balanced anaesthesia, lengthy duration of anaesthesia, and abdominal and orthopaedic operations appeared to be most frequently associated with postoperative emetic symptoms.
Sevoflurane for ENT‐surgery in children A comparison with halothane
Authors: Johannesson G. P. , Floren M. , Lindahl S. G. E.
Published: January 2009

Sevoflurane, a new volatile anesthetic agent, is of great potential interest in pediatric anesthesia. Its use for ENT surgery in children was compared with halothane in this study.

Altogether 40 children participated in the investigation. In 18 (median age 4.2 years), halothane was used. The remainder (median age 4.0 years) were anesthetized with sevoflurane. After rectal premedication with midazolam and atropine, anesthesia was induced by mask (the agent in O2/N2O, 40/60) using a Mapleson D system. The trachea was intubated without the use of muscle relaxants and the children were then allowed to breathe spontaneously at fresh gas flows set high enough to avoid rebreathing. Hemoglobine oxygen saturation (SpO2), inspired and expired gas concentrations, respiratory rate (RR), heart rate (HR), ECG and blood pressure were followed.

Equianesthetic concentrations of the agents were used and induction characteristics were comparable between the two agents. RR and end‐tidal CO2 tensions were similar in the two groups. HR and systolic blood pressures were, however, higher with sevoflurane. Cardiac arrhythmias were seen more frequently with halothane (61%) than with sevoflurane (5%). During emergence, postoperative nausea/vomiting was more frequent after halothane anesthesia. Initially, postoperative excitement occurred more often after sevoflurane, when paracetamol was given during anesthesia, which was reduced (P<0.01) when paracetamol was given at the time for premedication. It is concluded that sevoflurane is an excellent induction agent, and maintains heart rate and systolic blood pressure better than when halothane is used. The incidence of cardiac arrhytmia is lower with sevoflurane than with halothane. Sevoflurane anesthesia does, however, result in a high rate of postoperative excitement after ENT surgery, a factor that must be addressed prior to anesthesia.
Venous blood gas analysis for evaluation of blood circulation of the hand during continuous axillary block
Authors: Larsen V. H. , Treschow M.
Published: January 2009

Computer analysis of blood gas measurements was used to evaluate the effect of a continuous axillary block on the circulation of the hand of a patient suffering from regional circulatory insuffiency due to ligation of the brachial artery. Venous blood samples drawn from the cephalic vein were analysed at 0, 1, 2.5 and 18 hours after the blockade. Improved circulation of the hand was indicated by decreased arterio‐venous oxygen difference and increased venous oxygen partial pressure following the blockade. The advantage in using the extended blood gas analysis is the possibility of estimating the main factors influencing tissue oxygenation: oxygen capacity, oxygen partial pressure and the haemoglobin oxygen affinity.
Spinal subdural bleeding after attempted epidural and subsequent spinal anaesthesia in a patient on thromboprophylaxis with low molecular weight heparin
Authors: Sternlo J.‐E. , Hybbinette C.‐H.
Published: January 2009

Despite the extensive use of low molecular weight heparins (LMWH) for thromboprophylaxis, only two serious complications have thus far been reported where spinal haematomas were incurred after epidural and spinal blocks in patients on such treatment. In our patient, who was on thromboprophylaxis with the LMWH drug enoxaparin, catheter epidural anaesthesia was abandoned due to a bloody tap and superseded by spinal anaesthesia. More than 40 hours later she had developed a paraparesis and complete sensory loss in the lower extremities. The MRT image showed haematomas epi‐ and subdurally, as well as subarachnoidally, but no epidural bleeding was seen at laminectomy.
Anaesthetic implications of long term diabetic complications
Authors: Jørgensen B. G. , Holm H. E.
Published: January 2009

A case history in which a patient suffering from long‐term diabetes mellitus underwent vascular surgery of a lower extremity is presented. Anaesthesia was commenced with an epidural anaesthesia, but due to insufficient analgesia combined with a high thoracal block general anaesthesia was added. The course was complicated because of cardiomyopathy, autonomic neuropathy, difficult laryngoscopy, aspiration of gastric content, and acute renal failure. Anaesthetic implications of long‐term diabetes mellitus are discussed.
A simplified concept for controlling oxygen mixtures in the anaesthetic machine — better, cheaper and more user‐friendly?
Authors: Berge J. A. , Gramstad L. , Grimnes S.
Published: January 2009

Modern anaesthetic machines are equipped with several safety components to prevent delivery of hypoxic mixtures. However, such a technical development has increased the complexity of the equipment. We report a reconstructed anaesthetic machine in which a paramagnetic oxygen analyzer has provided the means to simplify the apparatus. The new machine is devoid of several components conventionally included to prevent hypoxic mixtures: oxygen failure protection device, reservoir O2 alarm, N2O/air selector, and proportioning system for oxygen/nitrous oxide delivery. These devices have been replaced by a simple safety system using a paramagnetic oxygen analyzer at the common gas outlet, which in a feed‐back system cuts off the supply of nitrous oxide whenever the oxygen concentration falls below 25%. The simplified construction of the anaesthetic machine has important consequences for safety, cost and user‐friendliness. Reducing the complexity of the construction also simplifies the pre‐use checkout procedure, and an efficient 5‐point check list is presented for the new machine.
The accuracy of reference lists in Acta Anaesthesiologica Scandinavica
Authors: Nishina K. , Asano M. , Mikawa K. , Maekawa N. , Obara H.
Published: January 2009

To determine the accuracy of bibliographic citation in Acta Anaesthesiologica Scandinavica. We reviewed all 1990 volumes and part of 1994 volumes of the journal and sequentially numbered all references appearing in those years (n = 2701 and 2158 in 1990 (No. 1‐No. 8) and 1994 (No. 1‐No. 5), respectively). We randomly selected 100 references from each year. After citations of nonjournal articles were excluded, the remaining 195 citations were carefully scrutinized. Authors' names, article title, journal title, volume number, page numbers, and year w7ere examined in each selected reference. A reference was deemed correct if each element of the citation was identical to its source. Of the examined references, 40% and 45% contained one or more errors in 1 990 and 1994, respectively. The elements most likely to be inaccurate were, in descending order of frequency, article title, author, and page number. No significant differences existed in the error rate between the two years. We have found many citation errors in the reference lists of Acta Anaesthesiologica Scandinavica and no improvement in these latest four years. All contributors to Acta Anaesthesiologica Scandinavica should thoroughly check the accuracy of reference lists.
The effect of ketanserin upon postoperative blood pressure, cerebral blood flow and oxygen metabolism in patients subjected to craniotomy for cerebral tumours
Authors: Felding M. , Cold G. E. , Jagobsen C.‐J. , Stjernholm P. , Voss K.
Published: January 2009

Hypertension and cerebral hyperperfusion are often seen in the immediate postoperative period after craniotomy for supratentorial tunours. This study was performed to evaluate the effect of ketanserin, given at the end of the peroperative period, upon cerebral blood flow (CBF), and cerebral metabolic rate of oxygen (CMRO2) before extubation. Mean arterial blood pressure (MABP), cerebral arterio‐venous oxygen content difference (AVDO2), PaO2, and PaCO2 were repeatedly measured during the operation, and 180 minutes after extubation. Ten patients were included in this study. The results were compared to those from a recent study in which ten patients served as control. All patients were anaesthetized with thiopentone, fentanyl, nitrous oxide 67%, halo‐thane 0.5% anesthesia. Ten patients were given ketanserin 10–20 mg (mean 18,5 mg) before extubation. There was no significant difference in CBF‐ and CMRO2 values between the two groups. During the period between closure of the dura and 5 minutes after extubation, an increase in MABP was observed in the control group (P<0.05) but not in the ketanserin group. During the same period, a decrease in AVDO2 was observed in both groups (P<0.05) and during the next 10 minutes an increase was observed. However, no difference in AVDO2 values between the two groups was found.

These findings suggest that peroperative treatment with ketanserin reduces postoperative hypertension without influencing the cerebral blood flow or metabolism.
Low flow anaesthesia reduces occupational exposure to inhalation anaesthetics Environmental and biological measurements in operating room personnel
Authors: Imberti R. , Preseglio I. , Imbriani M. , Ghittori S. , Cimino F. , Mapelli A.
Published: January 2009

In the present study we evaluated the occupational exposure to N2O and isoflurane during open circuit (OC) (fresh gas flow ≥ minute volume) and low flow (LF) (fresh gas flow=1.5 1/min) anaesthesia. The effects of active scavenging and of a charcoal filter positioned on the exhausting branch of the ventilator on environmental and urinary concentrations of inhalation anaesthetics were also investigated. The study was carried out in the same operating room provided with non‐recirculating air changes (10 per hour). It involved anaesthetists and nurses during routine activity. N2O and isoflurane concentrations (time‐weighted average) were measured after 3‐hour continuous exposure: 1) in the environment at the level of the personnel's breathing zone (Ci); 2) in the environment at the ventilator zone (C); 3) in urine (Cu). During OC anaesthesia without active scavenging the breathing zone concentration of both N2O and isoflurane was very high (194.6±15.2 and 5.0±0.4 ppm, respectively). The activation of the scavenging greatly reduced the breathing zone concentration of N2O (31.6±4.1 ppm) and isoflurane (1.7±0.2 ppm). LF anaesthesia (with active scavenging) significantly reduced the environmental concentration of both anaesthetics (Ci N2O and isoflurane 22.7±1.8 and 0.6±0.04 ppm, respectively). During LF anaesthesia the breathing zone concentration of N2O remained low, even without scavenging (22.7 ±1.8 ppm). Similar results were obtained by measuring N2O and isoflurane concentrations at the ventilator zone and in urine. The application of a charcoal filter to the exhausting branch of the ventilator during LF anaesthesia without active scavenging reduced the environmental concentration of isoflurane to a lower value than that obtained with OC anaesthesia with active scavenging (Ci 0.88±0.1 vs 1.7±0.2 ppm). A linear correlation was found between environmental (Ci) and urinary concentrations of N2O and isoflurane. Our data show that LF anaesthesia reduces the exposure of the operating room personnel to inhalation anaesthetics. A charcoal filter positioned on the exhausting branch of the ventilator in substitution of the active scavenging is very effective in reducing isoflurane pollution. The evaluation of the urinary concentration of inhalation anaesthetics is a simple and reliable method of monitoring occupationally exposed personnel.
Desmopressin acetate does not reduce blood loss during total hip replacement in patients receiving dextran
Authors: Schött U. , Sollén C. , Axelsson K. , Rugarn P. , Allvin I.
Published: January 2009

The blood loss‐reducing effect of desmopressin during dextran therapy was studied in a double‐blind fashion in 79 elderly but otherwise healthy patients with preoperative normal bleeding time undergoing total hip replacement for primary coxarthrosis. An infusion of desmopressin (0.3 μg/kg body weight) or placebo was randomly administered immediately after administration of spinal anaesthesia and six hours later. Haemostasis was evaluated on the basis of vWF: ristocetin cofactor activity, FVIII: C activity, human tissue plasminogen activator (tPA), plasminogen activator inhibitor type (PAI), ß‐thromboglobuline (ßTG) and a clot impedance test (Sonoclot). There were no statistically significant differences (P>0.05) in mean blood loss or transfusion requirements between the placebo and the desmopressin group. There was a significantly increase (P<0.01) both in vWF: ristocetin cofactor and in FVIII: C activity after both infusions of desmopressin compared with placebo. There was no significant difference in ßTG, tPA, PAI or Sonoclot analysis between the groups. In conclusion, desmopressin did not reduce blood loss in patients undergoing total hip replacement.
Effect of dopexamine on calculated low gastric intramucosal pH following valve replacement
Authors: Gårdebäck M. , Settergren G. , ÖHquist G. , Tirén C.
Published: January 2009

Gastric tonometry was used to study the possible effect of dopexamine infusion on a low calculated intramucosal pH (pHi) as a sign of splanchnic ischemia.

Measurements were made during surgery and for approximately 18 hours postoperatively on 19 non‐selected adult patients undergoing valve replacement. Patients developing a postoperative pHi>7.30 were randomized to receive dopexamine (2 μg · kg‐1min‐1) or placebo in a double blind fashion. Eighteen patients wore randomized, 10 to receive dopexamine and 8 to placebo.

The calculated pHiremained unchanged for the first 2 hours in both groups. After 4 hours a significant (P<0.05) decrease in pHiwas noted in the dopexamine group which remained significantly below the placebo group during the monitoring period. The dopexamine treated patients had a significantly longer period of low pHibut the pH‐gap i.e. the difference between arterial pH and pHidid not differ between the two groups. Patients with postoperative complications, defined as infections (2), myocardial infarction (1), single‐ (2) or multiple organ failure and death (1), did not have longer periods with pHibelow 7.30. In these patients, however, a pH‐gap >0.12 occurred more often than in those without complications, indicating that an increased incidence of complications was related to a pH‐gap >0.12.

It is our opinion that true mucosal ischemia is best detected by estimating the difference in carbon dioxide tension between arterial blood and mucosa. This can be expressed either directly as PCO2‐gap (PtonCO2‐PaCO2) or indirectly as pH‐gap.
Postdural puncture headache (PDPH): Onset, duration, severity, and associated symptoms: An analysis of 75 consecutive patients with PDPH
Authors: Lybecker H. , Djernes M. , Schmidt J. F.
Published: January 2009

Among 873 consecutive patients who had undergone a total of 1021 spinal anaesthesias involving puncture of the lumbar dura, 75 (7.35%) complained of Postdural Puncture headache. (PDPH). The severity of each patient's PDPH was categorized, on a scale from mild to severe, on the basis of the onset, duration, severity of the heActa ches, and the degree to which they were accompained by auditory and vestibular symptoms. In the patients who developed PDPH, 65% developed symptoms within 24 hours of the lumbar punctures and 92% developed symptoms within 48 hours.

For the patients who recovered spontaneously the mean duration of the PDPHs was 5 days, with a range of 1–12 days. PDPH was characterized by headachches that were influenced by the patient's posture and the severity of PDPH was categorized as follows:

Mild PDPH resulted in a slight restriction of their physical activity. These patients were not confined to bed and had no associated symptoms.

Moderate PDPH forced the patient to stay in bed for part of the day, and resulted in restricted physical activity. Associated symptoms were not necessarily present.

Severe PDPH Patients were bedridden for the entire day and made no attempt to raise their head or to stand. Associated symptoms were always present.

Fortyfive of the PDPH patients (60%) recovered spontaneously. Of these, 8 patients (11%) were categorized as mild cases of PDPH, 14 (19%) as moderate, and 23 (30%) patients as severe cases of PDPH. Thirty of the PDPH patients (40%) were treated with an autologous epidural bloodpatch (AEBP). Of these, 27 patients (36%) were classified as severe and 3 patients (4%) as moderate PDPH.

ASSOCIATED SYMPTOMS were present in all patients who had severe PDPH and in 86 percent of the patients who had moderate degrees of PDPH. Of all the patients with PDPH, 60% complained of nausea, 24% of vomiting, 43% of stiffness of the neck, 13% of ocular symptoms, and 12% of auditive symptoms. The headches in the PDPH patients were localized to the frontal region, bilaterally, in 25% of the cases, occipitally in 27% of the cases and in both regions in the remaining 45% of the patients.
Epidural blood patch illustrated by CT‐epidurography
Authors: Djurhuus H. , Rasmussen M. , Jensen E. H.
Published: January 2009

Four patients, who received epidural blood patch to treat postdural puncture headache, were examined with computed tomography in order to demonstrate the distribution of the injected blood. Blood alone could not be identified, but adding 2 ml contrast agent Iohexol 180 mg J/ ml (Omnipaque®, Nycomed Imaging) to 18 ml blood gave an excellent demonstration of the distribution of the blood in the epidural space, both cranio‐caudally (7–14 segments) and spatially in relation to the epidural septae. The blood‐contrast media had a strong affinity to the dural sac. There was no support of the spacefilling effect of blood patch.
Effects of organic nitrate vasodilators on platelet function before and after cardiopulmonary bypass
Authors: Muikku O. , Kuitunen A. , Hynynen M.
Published: January 2009

Various in vitro, ex vivo and in vivo tests have shown that organic nitrates attenuate platelet function. Because organic nitrates are commonly administered to patients undergoing cardiac surgery, the postoperative bleeding tendency observed in these patients might be strengthened by nitrates. Therefore, we compared the acute effects of nitroglycerin (0.5 μg kg‐1 min‐1) and isosorbide dinitrate (0.5 or 2.5 ng kg‐1 min‐1) with those of placebo on platelet function both before and after cardiopulmonary bypass in 40 patients undergoing coronary artery bypass grafting (CABG). Bleeding time, platelet retention on glass beads, i.e. platelet adhesiveness, and thromboel‐astograph tracings were used as indicators of platelet function. Although nitroglycerin and isosorbide dinitrate induced significant haemodynamic changes, e.g. decreases in arterial and pulmonary arterial pressure, they had no significant effects on the indices of platelet function. We conclude that, when given in haemodynamically effective doses, neither nitroglycerin nor isosorbide dinitrate have any measurable acute effect on platelet function as evaluated with on‐site tests in patients undergoing CABG surgery.
The effects of midazolam, droperidol, fentanyl, and alfentanil on phagocytosis and killing of bacteria by polymorphonuclear leukocytes in vitro
Authors: Krumholz W. , Endrass J. , Knecht J. , Hempelmann G.
Published: January 2009

Polymorphonuclear leukocytes (PMNL) make an outstanding contribution to the defence against invading bacteria. We studied the effects of midazolam, droperidol, fentanyl, and alfentanil on phagocytosis and killing of Staphylococcus aureus and Escherichia coli by PMNL in vitro.

Using a method described by Eggleton et al. (5), PMNL were isolated from venous blood samples obtained from ten volunteers. The fluorescence microscopic method mentioned by Bellinari‐Pires et al. (6) was used to examine phagocytosis and killing.

Whereas both midazolam and droperidol caused a significant inhibition of phagocytosis as well as bactericidal activity, fentanyl and alfentanil did not influence these PMNL functions.

In order to find out whether midazolam and droperidol are able to intensify perioperative bacterial infections in vivo as well, additional clinical studies should be conducted.
Diltiazem does not increase ventricular fibrillation threshold during hypothermia
Authors: Bjørnstad H. , Jenssen D. , Mortensen E.
Published: January 2009

This study was designed to investigate whether the calcium channel blocker diltiazem affects the threshold for ventricular fibrillation during hypothermia in dogs.

Ten dogs were cooled from 37 to 25°C and rewarmed to 37°C. The threshold for ventricular fibrillation was determined at body temperatures 37, 34, 31, 28 and 25°C by programmed electrical stimulation using a stimulation protocol which involved application of maximal five extrastimuli. At 25°C, six dogs were given an i.v. bolus dose of 100 μg‐kg‐1followed by a continuous infusion of 100 μg‐kg‐1‐h‐1of diltiazem hydrochloride. The other four dogs, were given no drugs at 25°C and served as a control group. The dogs were rewarmed, and the stimulus protocol was performed at the same temperatures as during cooling.

Cooling from 37 to 25°C reduced the treshold for ventricular fibrillation in both groups. Heart rate were reduced, monophasic action potential duration at the apex and base of the heart increased from 167±5 ms to 469±17 ms and from 164±5 ms to 466±1 7 ms, respectively, when the temperature was reduced. The ventricular effective refractory period increased from 176±9 ms at 37°C to 472±15 ms at 25°C. Cooling increased QRS time on the ECG from 55±4 ms to 138±13 ms. Addition of diltiazem at 25°C did not affect the threshold for ventricular fibrillation during rewarming. Further, diltiazem at 25°C did not affect the heart rate or refractoriness. Cooling reduces the threshold for ventricular fibrillation. During hypothermia, the calcium channel blocker diltiazem does not seem to affect the threshold for ventricular fibrillation.
Are the cardiovascular actions of dopamine altered by isoflurane?
Authors: Raner C. , Biber B. , Henriksson B.‐Å. , Lundberg J. , Martner J. , Winsö O.
Published: January 2009

Dopamine seems theoretically to be a rationale choice when adrenergic support is needed to counter undesired cardiovascular depressant effects of isoflurane. Although the cardiovascular effects of isoflurane (ISO) and exogenous dopamine (DA) are well documented, there are no reports on their pharmacological interaction. The effects of ISO 1.4% (MAC 1.0) on the cardiovascular response to exogenous DA were studied in dogs during chloralose anesthesia. Instrumentation included catheterizations of the femoral artery (for aortic pressures and heart rate, HR), the pulmonary artery (for thermodilution cardiac output, CO, and pulmonary arterial pressures) and the left ventricle (for tip‐manometer measured left ventricular end‐diastolic pressure, LVEDP). ISO per se decreased HR (‐16%), mean arterial pressure (MAP; ‐33%), CO (‐29%), left ventricular dP/dt (LV dP/dt; ‐51%), and increased pulmonary artery occlusion (PAOP; +64%) and LVEDP (+28%). Prior to ISO, DA increased MAP, CO stroke volume (SV), LV dP/dt and LV dP/dt/SAP (systolic arterial pressure) at the dose 10 ug · kg‐1· min‐1. At the dose 20 μf · kg‐1· min‐1DA, besides these effects, increased PAOP and mean pulmonary artery pressure (MPAP).During ISO, DA at the dose 10 μg · kg‐1· min‐1restored MAP, CO, and SV to pre‐ISO control levels, while LV dP/dt was increased to +96% above the pre‐ISO control level. At the dose 20 μg · kg‐1· min‐1, DA increased MAP (+33%), LV dP/dt (+172%), PAOP (+ 132%) and MPAP (+50%) above pre‐ISO control levels. The cardiac effects of DA were similar to when it was given alone. However, the increase in SVR (at the dose 20 μg · kg‐1· min‐1) and MAP (at the 10 and 20 μg · kg‐1· min‐1doses) by DA was significantly more pronounced with ISO than without ISO.

In conclusion, the pressor effects of DA seem to be potentiated by ISO. DA restores systemic arterial pressure during ISO anesthesia by attenuating the cardiac depressant effects of ISO and by increasing SVR above pre‐ISO control levels.
Methylmethacrylate monomer produces direct relaxation of vascular smooth musclein vitro
Authors: Karlsson J. , Wendling W. , Chen D. , Zelinsky J. , Jeevanandam V. , Hellman S. , Carlsson C.
Published: January 2009

Methylmethacrylate bone cement is associated with severe hypotensive reactions during surgery and anesthesia. The purpose of thisin vitrostudy was to determine if methylmethacrylate monomer could produce hypotension by acting directly on vascular smooth muscle.

Segments of human saphenous vein or rabbit thoracic aorta were cut into rings. The rings were mounted in isolated tissue chambers in order to measure isometric tension development.

Methylmethacrylate monomer (methylmethacrylic acid ester) produced direct relaxation of venous or aortic rings preconstricted with either potassium ion or noradrenaline. The relaxation was concentration‐dependent, occurring at concentrations from 10‐1to 10‐1M. The relaxation of rabbit aortic rings {preconstricted with noradrenaline) was unaffected by pre‐treatment with atropine, propranolol, cimetidine, indomethacin, or methylene blue. Endothelial stripping with Triton X‐100, sufficient to completely abolish acetylcholine‐induced relaxation, also had little effect on methylmethacrylate‐induced relaxation. Methylmethacrylate produced direct relaxation of rabbit aortic rings constricted with either potassium or noradrenaline in calcium‐deficient media, and inhibited subsequent calcium‐induced constriction.

These results suggest that methylmethacrylate monomer may interfere with intracellular and extracellular calcium mobilization and excitation/contraction coupling in vascular smooth muscle. The direct relaxation of venous and arterial smooth muscle produced by methylmethacrylate monomer may contribute in part to the hypotension that can occur when acrylic bone cement is employed during orthopedic procedures.
Hemodynamic predictors of atrial fibrillation or flutter after coronary artery bypass grafting
Authors: Frost L. , Jacobsen C.‐J. , Christiansen E. H. , MoSlgaard H. , Pilegaard H. , Hjortholm K. , Thomsen P. E. B.
Published: January 2009

The cumulated incidence of atrial fibrillation or flutter after coronary artery bypass grafting is 30%. The causes of these arrhythmias have not yet been sufficiently identified. We therefore undertook the present study to analyze the possible association of hemodynamic function during the various phases of coronary artery bypass grafting and the later development of atrial fibrillation/flutter.

Hemodynamic function was measured with a pulmonary artery catheter in 120 consecutive patients undergoing elective coronary artery bypass surgery.

Thirty‐five (29%) of the patients developed atrial fibrillation/flutter. Logistic regression analysis identified independent predictors of atrial fibrillation/flutter: After induction of general anesthesia, the relative risk (95% confidence interval) of older age was 1.09/year (1.03–1.16), and the reduction in relative risk by an increase in left ventricular stroke work was 0.96/gm (0.93–0.99). After weaning from the extracorporeal circulation the independent significant predictors were age, relative risk 1.07/year (1.01–1.13), and increased central venous pressure, relative risk 1.12/mm Hg (1.00–1.26). At the time of admission to the intensive care unit, the relative risk of age was 1.10/year (1.03–1.18), and the relative risk of an increased central venous pressure was 1.26/mm Hg (1.06–1.49). However, the best prediction model (prediction after induction of general anesthesia) only provided a median predicted probability of atrial fibrillation/flutter of 0.37 for the patients who had atrial fibrillation/flutter, and a median predicted probability of atrial fibrillation/nutter of 0.20 for the patients without these arrhythmias. We identified possible hemodynamic predictors of atrial fibrillation/flutter after coronary bypass surgery, but the use of a risk stratification for development of atrial fibrillation/flutter based on hemodynamic function cannot be recommended.
Adenosine for per‐operative blood pressure control in an infant with neuroblastoma
Authors: Selldén H. , Kogner P. , Sollevi A.
Published: January 2009

We describe a child with a localised pelvic neuroblastoma and a hypertensive crisis during the first weeks of life due to elevated systemic norepinephrine of tumoural origin. In spite of treatment with high doses of α‐blockers, blood pressure did not respond fully and the boy had a very unstable circulation. Surgery was performed at one month of age. Adenosine, a potent short‐acting vasodilator, was used for peroperalive blood pressure control to protect the patient from an uncontrolled hypertensive crisis.

During tumour manipulation the child became hypertensive with systolic pressure exceeding 130 mm Hg and adenosine infusion (100 μg‐kg‐1 · min‐1) was started with a prompt normalisation of the blood pressure. Adenosine infusion could be discontinued after tumour removal.

Norepinephrine, dopamine, homovanillic acid and vanillylmandelic acid in urine were elevated preoperatively and normalised at follow up. Plasma concentrations of norepinephrine and dopamine were elevated preoperatively. Norepinephrine increased during hypertension due to tumour manipulation. Plasma neuropeptide Y increased during tumour manipulation but still within the normal range for infants.

It is concluded that adenosine can be used peroperatively in children with severe hypertension and in this case no adverse effects of adenosine were noted. Furthermore, tumour synthesis and systemic release of norepinephrine, but not neuropeptide Y, contributed to hypertension in this child with neuroblastoma.
Desflurane: a new volatile anesthetic for cesarean section: Maternal and neonatal effects
Authors: Abboud T. K. , Zhu J. , Richardson M. , Da Silva E. Peres , Donovan M.
Published: January 2009

Desflurane, a new volatile anesthetic agent with low blood/gas solubility, has recently been studied in clinical and animal trials but its use in obstetrics has not been adequately evaluated. This prospective study was undertaken to evaluate the maternal and neonatal effects of desflurane in obstetrical patients.

Seventy‐five healthy parturients undergoing primary or repeat cesarean section were randomly assigned to one of three groups of 25 each, end‐tidal 3% desflurane, 6% desflurane or 0.6% enflurane, combined with 50% N2O and O2. All patients had rapid sequence induction of anesthesia with thiopentone sodium followed by succinyl‐choline for tracheal intubation. After delivery, anesthesia was maintained with reduced concentration of desflurane or enflurane with 67% N2O in O2, supplemented by butorphanol tartrate. Maternal hemodynamic parameters, blood loss and maternal awareness during surgery were monitored. Neonatal outcome was evaluated by Apgar scores, neurological and adaptive capacity scores (NACS), cord blood gas and acid‐base status, and time to sustained respiraton (TSR).

Maternal blood loss did not differ significantly between the three groups and none of the patients developed intraoperative awareness. All three groups responded to psychomotor performance equally fast. Patients in all three groups developed transient hypertension and tachycardia during induction of anesthesia which returned to baseline values in approximately 5 min. Neonatal outcome was equally good in the three groups. More neonates in the 6% desflurane group had TSR>90 s compared to the 3% desflurane group (P<0.05). It is concluded that desflurane in subanesthetic concentration is a safe supplement to N2O‐O2 mixture for cesarean section with the advantage of rapid and smooth recovery. 3% desflurane in N2O‐O2 seems to be an adequate concentration for cesarean section for the healthy parturient.
A new method of using gas exchange measurements for the noninvasive determination of cardiac output: clinical experiences in adults following cardiac surgery
Authors: ÖSterlund B. , Gedeon A. , Krill P. , Johansson G. , Reiz S.
Published: January 2009

New mathematical algorithms have been applied to a computer controlled closed breathing circuit system for non‐invasive measurement of cardiac output (COniv). This system has been described in an animal study. Forty patients were studied 5 and 18 hours after cardiac surgery using the thermodilution technique as the reference (COtd). The variables entered into the algorithms for COniv were oxygen uptake, carbon dioxide elimination, end‐tidal carbon dioxide partial pressure, tidal volume and arterial oxygen saturation. Mixed venous carbon dioxide partial pressure was obtained from an automatically implemented short rebreathing manoeuvre. Pulmonary perfusion was calculated by a modified Fick equation for carbon dioxide and the shunt flow added to obtain COniv. During mechanical ventilation, there was a good agreement between COtd and COniv (r=0.8). The bias was ‐0.14 1/min and the precision was 0.77 1/min. The reproducibility of COniv was 0.03 1/min and for COtd ‐0.03 1/min with a standard deviation of the difference being 0.35 1/min for COniv and 0.31 1/min for COtd. In awake, but sedated extubated patients, the method proved unsatisfactory on account of uneven tidal volumes and difficulties with leakage around the mouth piece. We conclude that this new technique provides reliable and reproducible measures of cardiac output in sedated, ventilated patients.
Synergism between mivacurium and pancuronium in adults
Authors: Rautoma P. , Erkola O. , Meretoja O. A.
Published: January 2009

Mivacurium could be a useful agent as a final dose of a muscle relaxant following pancuronium if only additivily exists between these agents. We examined the interaction between mivacurium and pancuronium in 70 patients (ASA I‐II) during propofol‐alfentanil‐N2O‐C2anaesthesia. Neuromuscular function was monitored by adductor pollicis EMG.

Firstly we established dose‐response curves for mivacurium and pancuronium. Thereafter, 20 patients received a combination of 0.5 times the ED50doses of mivacurium and pancuronium (cMP) determined in the first part of this study. Patients were randomized to receive the cMP to the same IV‐line (n=10) or to two separate IV‐lines in opposite hands (n=10).

ED50values for mivacurium and pancuronium were 57.7 and 37.1 μg kg‐1, respectively. Maximal neuromuscular block following the cMP was 91.8 ±5.0% (mean±SD). This was highly significantly different from the estimated 50% NMB if only additivity exists between mivacurium and pancuronium (P=0.0001). After the cMP, the 25 75% recovery rime was 9.4± 1.3 min and the time to train‐of‐four ratio of 0.70 was 35.8±5.4 min. There was no statistical difference in any recorded neuromuscular parameter between the two subgroups receiving mivacurium and pancuronium to the same or to opposite hands (P>040).

We conclude that a significant synergism exists between mivacurium and pancuronium which may indicate that mivacurium does not produce a short‐acting NMB if given after pancuronium. We do not recommend using mivacurium together with pancuronium.
Statistical aspects in studies of preoperative fluid intake and gastric content
Authors: Søreide E. , Strømskag K. E. , Steen P. A.
Published: January 2009

Twelve randomised studies of preoperative intake of clear fluids and gastric content were reviewed and presented together with a separate study performed by the authors. A common deficiency in design was the omission of detailed information concerning randomisation procedures, distribution of data, and choice of statistical methods. Only one reviewed study included power calculations and only 3 reported 95% C.I. (Confidence Intervals). Deficiencies in design and data collection rendered the conclusion of two studies invalid. Incorrect use of statistical tests in some of the remaining studies may have resulted in non‐significant differences becoming statistically significant. This, however, did not change the main conclusion of a meta‐analysis that intake of clear fluids up to 2 hours before general Anaesthesia was safe as fluid intake either decreased or had no effect on gastric fluid volume.