bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of open heart surgery on oral mucous host defence systems
Authors: LÄHTEENMÄKI M. , TENOVUO J. , SALO M. , PERTTILÄ J.
Published: January 2009

Background: The immune response is affected by anaesthesia and surgery. This study was carried out on the effects of open heart surgery on the oral mucous host defence system, which is part of the common mucosal immune system.

Methods: Amylase, nonimmunological (lysozyme, myeloperoxidase, hypothiocyanite and thiocyanate) and immunological (IgA, IgG, and IgM) mucous host defence factors as well as oral bacterial flora were determined in the saliva of 18 patients undergoing open heart surgery preoperatively and on the 2nd, 3rd, and 7th postoperative days. To assess the specificity of the changes, the salivary flow rate and total protein content were also determined.

Results: Stimulated salivary flow decreased from 1.8 (1.3–2.2) ml/min (median; 25th and 75th quartiles) to 0.4 (0.3–0.5) ml/ min by the 2nd postoperative day and to 0.4 (0.2–1.0) ml/min by the 3rd postoperative day (P <0.001). Amylase, lysozyme, myeloperoxidase, total salivary peroxidase and thiocyanate levels increased, whereas hypothiocyanite levels decreased postoperatively (P < 0.01–0.001). Their total secretion rate, however, was reduced (P <0.05–0.001) owing to the lowered salivary flow rate. IgG and IgM concentrations were raised on the 2nd, 3rd and 7th postoperative days (P< 0.05–0.001), and IgA concentrations on the 2nd postoperative day (P <0.05). The total secretion of IgG and IgM as well as their salivary concentrations in relation to total protein concentrations also increased. The number of salivary anaerobically growing bacteria decreased postoperatively (P < 0.01), but the number of salivary streptococci remained unaffected.

Conclusions: Open heart surgery decreases the salivary secretion of nonimmunological host defence factors and increases the salivary secretion of IgA, IgG and IgM.
Effects of hypothermia and sternal retractors on median nerve somatosensory evoked potentials
Authors: PORKKALA T. , KAUKINEN S. , HÄKKINEN V. , JÄNTTI V.
Published: January 2009

Background: Somatosensory evoked potentials (SEPs) are altered by hypothermia, which is often used during cardiopulmonary bypass (CPB). However, the effect of hypothermia on SEP amplitudes is unclear. Also, the sternal retractors used during open heart surgery are reported to cause brachial plexus distension and SEP changes.

Methods: Median nerve SEPs under hypothermic CPB were studied in 29 elective patients scheduled for open heart surgery. In 23 patients who underwent left internal mammary artery (IMA) dissection, the effects of sternal retractors on cortical SEP before the initiation of CPB were investigated.

Results: A latency shift of all SEP components was detected when nasopharyngeal temperature decreased from 35.7(SD 0.4)°C to 27.8(SD 0.25)°C. The mean cortical N20 latency was increased by 39% (P< 0.0001), cervical N13 by 33% (P < 0.0001), and peripheral N9 by 27% (P <0.0001). The latency changes were reversible when normothermia was restored. The effect of hypothermia on SEP amplitudes was more complex. The mean amplitude of N20 decreased from 2.7 μV to 2.2 μV (P < 0.05) and the amplitude of N13 from 2.5 μV to 2.0 μV (P < 0.0001). In contrast, the N9 component showed an increase from 1.4 μV to 2.1 μV (P <0.0001) during hypothermia. The sternal retractors did not cause significant cortical SEP amplitude changes during IMA dissection or sternotomy. Also, the latency changes were small, although significant (P < 0.05).

Conclusion: Despite the moderate amplitude changes produced by hypothermia, SEPs can be successfully monitored during hypothermia. Theoretically, the different behaviour of amplitude in peripheral and cranial components of SEP during hypothermia is interesting. Hypothermia has a more profound effect on synaptic transmission, represented by the cortical N20 latency, than on the peripheral nerve conduction velocity. Intraoperative monitoring of temperature is essential whenever SEPs are recorded. The sternal retractors were not responsible for the intraoperative SEP changes.
The influence of anaesthetic techniques and type of delivery on peripartum serum interleukin‐6 concentrations
Authors: JONGH R. F. DE , BOSMANS E. P. , PUYLAERT M. J. , OMBELET W. U. , VANDEPUT H. J. , BERGHMANS R. A. , MAES M. , HEYLEN R. J.
Published: January 2009

Background: Interleukin‐6 is a pleiotropic cytokine with a wide range of physiological activities. It plays an important role in the immuno‐neuro‐humoral axis during stress and surgery.

Methods: Serum interleukin‐6 in parturients was measured on hospital admission, immediately after birth and 12 and 24 hours later. All parturients had uncomplicated pregnancies, and delivered vaginally without (n=31) or with (n=20) epidural analgesia, or underwent Caesarean section under epidural (n=20) or general (n=10) anaesthesia.

Results: Serum interleukin‐6 assayed immediately following Caesarean section was low, but peaked 12 hours later, irrespective of the anaesthetic technique or other foetomaternal characteristics. Patients who delivered vaginally showed the highest interleukin‐6 levels immediately after delivery. These were positively correlated with serum interleukin‐6 on admission and duration of labour. Serum interleukin‐6 was significantly higher in parturients who had epidural analgesia, and was significantly lower in those receiving intravaginal prostaglandins compared to those without prostaglandins.

Conclusion: The interleukin‐6 response after Caesarean section can be explained by a generalized acute phase response to surgery, with no anaesthetic, maternal or neonatal interference. The rapid increase in peripartum serum interleukin‐6 levels after vaginal delivery reflects, in part, cervical ripening or labour, their physiological triggers and psychological or physical stress. Regional anaesthesia, duration of labour and exogenous prostaglandin administration can modulate the peripartum interleukin‐6 response and subsequently the physiological effects of this cytokine.
Continuous low‐flow tracheal gas insufflation during partial liquid ventilation in rabbits
Authors: MESZAROS E. , OGAWA R.
Published: January 2009

Background: Both partial liquid ventilation (PLV) and tracheal gas insufflation are novel techniques for mechanical ventilation. In this study we examined whether PLV superimposed by continuous low‐flow tracheal gas insufflation (TGI) offers any advantage to the blood gases and lung mechanics in normal‐lung rabbits compared to the use of PLV only.

Methods: Eighteen anesthetized, paralyzed and mechanically ventilated rabbits were used. After obtaining a baseline PaCO2value between 29 and 39 mmHg (3.9 and 5.2 kPa), the animals were assigned to three equal groups according to the ventilation they received ‐ A group: PLV superimposed by TGI; B group: PLV only; and C group: continuous mandatory ventilation (CMV) superimposed by TGI. Serial arterial blood gases, pH and lung mechanics were measured.

Results: The animals in each group were hemodynamically stable. In the case of the A group, PaO2 continuously increased, and PaCO2 stabilized around 40.8±5.5 mmHg (5.4±0.7 kPa, mean±SD, NS). In the B group, the tendency for PaO2 to increase was not as definite; PaCO2 continuously increased from 35.2±2.3 mmHg (4.7±0.3 kPa) to 56.3±12.7 mmHg (7.5±1.7 kPa, P< 0.05) at the end of the experiment. In the C group, PaO2 and PaCO2 were stable during the observation period. The superimposition of TGI on PLV did not decrease the airway pressures compared to PLV alone.

Conclusion: In summary, continuous low‐flow TGI superimposed on PLV can decrease and stabilize the PaCO2 elevation caused by the initiation of PLV.
Postoperative epidural infusion of morphine and bupivacaine is safe on surgical wards
Authors: RYGNESTAD T. , BORCHGREVINK P. C. , EIDE E.
Published: January 2009

Background: There was an obvious need to improve the quality and safety of our postoperative pain treatment and to introduce an improved routine service on surgical wards.

Methods: It was decided to use postoperative epidural infusion of morphine 0.04 mg/ml and bupivacaine 2.5 mg/ml (0.25%): 4–8 ml/h as pain relief after major surgery. An education programme was run emphasising the benefits, side‐effects and the importance of regular monitoring of pain intensity, vital functions (respiratory rate, blood pressure, heart rate), motor function of the legs and the need for additional drugs in order to detect side‐effects as well as lack of adequate analgesic effect. A detailed observation sheet was used collecting information every 2 h throughout the epidural treatment period in order to secure monitoring and adjustment of the treatment. Close contact was maintained with the wards.

Results: We present a detailed analysis of our first 2000 postoperative patients, mainly after orthopaedic (46.1%), gastrointestinal (32.0%), urologic (8.7%) and vascular (8.5%) surgery. Duration of the treatment was less than 24 h in 41.4% and more than 48 h in 29.7%. Pain relief was adequate in most patients, best after vascular surgery in the lower extremities (mean VAS 0.15/10.0 (95% confidence interval 0.09–0.23)) and less after gastrointestinal (mean VAS 0.49/10 (0.43–0.54)) and thoracic surgery (mean VAS 0.59/10 (0.38–0.81)). The infusion was stopped due to respiratory depression in 3 patients (0.15%). Four (0.2%) had systolic blood pressure <80 mmHg and had to be treated with vasopressors. A total of 56 (2.8%) patients were considered to be problem patients due to excessive sedation (0.4%), hypotension (0.7%), respiratory depression (1.6%) or lower extremity paralysis (0.05%). All patients had urinary catheter until 6 h after termination of the epidural treatment. One patient had the epidural catheter accidentally placed subarachnoidally and experienced severe respiratory depression. No permanent sequelae were recorded in the postoperative patients, but 2 traumatised patients developed epidural abscesses after 3 weeks of treatment, which resulted in lower extremity paralysis. Late response to the warning signs might have contributed to the irreversible paraplegia.

Conclusion: Our experience with this postoperative epidural analgesia regime is favourable. It has been easy to administer and monitor. Pain relief was excellent, side‐effects were few and picked up by the established routines followed by the ward staff except in the 2 trauma patients who developed epidural abscesses. The staff on the surgical wards were motivated for this kind of work. Education and strict surveillance routines are mandatory in order to secure prompt action when warning signs develops (e.g. lower limb paralysis).
Caudal clonidine and bupivacaine for combined epidural and general anaesthesia in children
Authors: MOTSCH J. , BÖTTIGER B. W. , BACH A. , BÖHRER H. , SKOBERNE Th. , MARTIN E.
Published: January 2009

Background: Clonidine produces analgesia by actions on α2‐ad‐renoceptors and enhances both sensory and motor blockade from epidural injection of local anaesthetics. Low‐dose clonidine has been used so far for caudal injection in children. Our aim was to study the perioperative effects of high‐dose caudal clonidine when added to low concentration of bupivacaine for combined epidural and general anaesthesia in children.

Methods: After induction of general anaesthesia caudal block was performed either with 1 ml kg‐1 bupivacaine 0.175% with the addition of clonidine 5 μg kg‐1 (n=20), or with 1 ml kg‐1bupivacaine 0.175% (n=20). The intraoperative anaesthetic requirements, the perioperative haemodynamic effects, respiratory rate, sedation score, postoperative pain scores and side effects were assessed by a blinded observer. A patient‐controlled analgesia system was used for postoperative pain relief. The quality of postoperative pain relief was assessed using Smiley's pain analogue scale.

Results: Intraoperative haemodynamic responses did not differ between the groups. However, during emergence from general anaesthesia children in the clonidine group had significantly lower heart rates and blood pressures compared to children in the control group. In addition, heart rates and blood pressures were also lower in the clonidine group in the early postoperative period (P?< 0.05). Postoperative analgesia was significantly better in the clonidine group as evidenced by the total number of requests (3 vs 12, P< 0.05) and the total amount of tramadol (20.5 mg vs 72.8 mg, P < 0.05) administered. The duration of the caudal analgesia was significantly longer in the clonidine group (20.9±7.4 h vs 14.4±10.9 h, P< 0.05).

Conclusion: Our results suggest that caudal clonidine 5 μg kg‐1 enhances and prolongs caudal blockade with bupivacaine 0.175% in children. It also blocks sympathoadrenergic responses during emergence from anaesthesia. Sedation and cardiovascular effects are observed up to 3 h into the postoperative period.
Weight gain during pregnancy does not influence the spread of spinal analgesia in the term parturient
Authors: EKELØF N. P. , JENSEN E. , POULSEN J. , REINSTRUP P.
Published: January 2009

Background: It is still controversial whether the spread of spinal anaesthesia in pregnancy is influenced by particular physique. Investigation was based on a clinical observation that parturients with a pronounced “pregnant” physique, e.g. generalised oedema and heavy abdomen, tended to develop more cephalad sensory blockades than parturients without these physical signs. Using weight gain during pregnancy as a measure for the physique at term, we aimed to determine whether this parameter influences the distribution of analgesia after subarachnoidal injection of plain bupivacaine.

Methods: Thirty women presenting for elective Caesarean section were studied. All the women received 13.5 mg plain bupivacaine via subarachnoid injection at the L2_3 interspace. Thirty minutes after the injection, while the women were in the supine position with a left lateral tilt on a horizontal operating table, the maximum cephalad extent of sensory analgesia (loss of sensation to sharpness of pinprick) was determined.

Results: Neither weight gain during pregnancy (6–22 kg, range), height (152–185 cm), weight (56–98 kg) nor body‐mass index (20.2–31.8 kg/m2) correlated with the cephalad spread of sensory blockade.

Conclusion: In parturients, weight gain during pregnancy, height, weight and body‐mass index did not influence the extent of sensory analgesia after subarachnoidal administration of plain bupivacaine.
Pharmacodynamic modelling of the analgesic effects of piritramide in postoperative patients
Authors: KIETZMANN D. , BOUILLON T. , HAMM C. , SCHWABE K. , SCHENK H. , GUNDERT‐REMY U. , KETTLER D.
Published: January 2009

Background:The concentration‐effect relationship of piritramide, a synthetic opioid analgesic predominantly used for postoperative analgesia and analgosedation, has not been reported so far.

Methods:Twenty‐four patients of both genders aged 58.1 (11.7) yr (mean (SD)) received inhalational anaesthesia for abdominal surgery. Postoperative pain was assessed with a visual analogue scale (VAS). Analgesia was provided with piritramide, infused at a rate of 7 μg kg‐1min‐1until analgesia was considered sufficient (VAS<25) or up to a maximum dose of 0.2 mg/kg. The plasma concentrations of piritramide were determined by gas chromatography. An inhibitory fractional sigmoid Emax‐model was used to describe the relation between effect site concentration and perceived pain.

Results:The equilibration half‐life between plasma and effect site concentrations (T1/2(keo) was 16.8 min (median; range: 4.4–41.6 min). The steady‐state plasma concentration required to produce 50% of maximum analgesia (EC50) was 12.1 ng/ml (range: 2.9–29.8 ng/ml) and correlated with initial pain intensity. The slope factor γ was 1.9 (range: 0.5–6.1) and increased with age. Clinically relevant respiratory depression did not occur. Due to the relatively large equilibration half‐life of the effect compartment, the context‐sensitive half‐time of the effect site concentrations after short‐time administration (<2 h) clearly exceeded those of alfentanil, sufentanil, and fentanyl.

Conclusions:The analgesic effect of piritramide was adequately described by an inhibitory fractional Emax‐model. In order to overcome the pronounced hysteresis, piritramide should initially be administered as an intravenous bolus of at least 5 mg.
Interaction between sufentanil and U‐50488H with respect to antinociception and respiratory depression in rats
Authors: VERBORGH C. M. L. , CAMU F. , MEERT T. F.
Published: January 2009

Background:Opiate receptors have been argued to differentially regulate analgesia and respiratory depression. In order to validate possible interactions between the opiate mu‐ and kappa‐receptors, interactions between sufentanil and U‐50488H were studied in rats.

Methods:Rats equipped with an arterial catheter were tested in the tail flick latency (TFL) test after intravenous treatment with sufentanil (a mu‐agonist), U‐50488H a kappa‐agonist) or fixed ratio combinations of both drugs. Simultaneously, respiratory changes were monitored by blood gas analysis.

Results:The ED50s of sufentanil for a TFL >6.0 and <10.0 s were 0.0002 and 0.00059 mg/kg. For U‐50488H the corresponding values were 1.53 and 8.11 mg/kg. Using a fixed dose ratio of 1/10000, an additivity was demonstrated between sufentanil and U‐50488H in terms of antinociception. With regard to respiratory parameters, PaCO2significantly increased after all doses of sufentanil early after treatment. At the higher doses tested, there was also a decrease in PaO2and O2saturation. For U‐50488H only the highest doses resulted in an early and small shift in PaCO2. The combination of sufentanil/U‐50488H resulted in only a small increase in PaCO2at the highest dose regimen tested.

Conclusion:The results presented here demonstrate that drug mixtures of sufentanil and U‐50488H can be additive with respect to antinociception with additionally less risk for respiratory side‐effects, as compared with sufentanil alone. Therefore, a combination of mu‐ and kappa‐opiate receptor agonists might be more beneficial than each agent alone.
Minimum alveolar concentration of sevoflurane for tracheal extubation in children
Authors: HIGUCHI H. , URA T. , TAODA M. , TANAKA K. , SATOH T.
Published: January 2009

Background: One advantage of tracheal extubation during deep anaesthesia is that respiratory complications are reduced. Sevoflurane is a suitable anaesthetic agent for children. This study was conducted to determine the minimum alveolar concentration of sevoflurane required to prevent cough or movement during and after tracheal extubation (MACextubation).

Methods: We studied 30 nonpremedicated children, aged 2–10 yr, undergoing plastic surgery. They were allocated randomly to five groups (end‐tidal sevoflurane concentrations: 2.0, 2.5, 3.0, 3.5, 4.0%). After surgery, 60% nitrous oxide was discontinued and the target concentration of sevoflurane was maintained for at least 10 min in 100% oxygen, then the trachea was extubated to determine MACextubation. Logistic regression was used to estimate MACextubation. of sevoflurane.

Results: MACextubation. was 2.3 (0.2; standard error)% (95% confidence limits: 1.2% and 2.7%).

Conclusions: Tracheal extubation in 50% of anaesthetized children age 2–10 yr may be accomplished without coughing or moving at 2.3% end‐tidal concentration of sevoflurane.
Intravenous dolasetron and ondansetron in prevention of postoperative nausea and vomiting: a multicenter, double‐blind, placebo‐controlled study
Authors: KORTTILA K. , CLERGUE F. , LEESER J. , FEISS P. , OLTHOFF D. , PAYEUR‐MICHEL C. , WESSEL P. , NAVE S. , HAHNE W. , BROWN R.
Published: January 2009

Background: Intravenous dolasetron mesilate has shown efficacy in the prevention of postoperative nausea and vomiting (PONV) when administered as a single dose prior to emergence from anesthesia. This trial compared intravenous dolasetron and ondansetron for the prevention of PONV when administered at induction of anesthesia.

Methods: This double‐blind, placebo‐controlled, multicenter trial randomized patients to one of four single IV treatments: placebo, 25 or 50 mg dolasetron, or 4 mg ondansetron. Efficacy was measured by complete response (0 emetic episodes and no rescue medication), nausea severity and patient satisfaction as measured on a visual analog scale (VAS), investigator's rating of nausea severity, and total response (complete response with no nausea [≤ mm VAS]).

Results: 514 patients at 24 sites were evaluated for efficacy. The 50 mg dolasetron and 4 mg ondansetron doses were statistically equivalent, and superior to placebo, for all efficacy measures. Complete response rates were 49%, 51%, 71% and 64% for placebo, 25 and 50 mg dolasetron, and ondansetron, respectively. Dolasetron 50 mg was statistically superior to 25 mg dolasetron for complete response, total response, VAS maximum nausea, time to first emetic episode, and patient satisfaction. The majority of adverse events were of mild‐to‐moderate intensity. Headache was the most frequently reported treatment‐related adverse event with a 3%‐5% incidence across treatments.

Conclusion: When given at induction of anesthesia, 50 mg intravenous dolasetron is equivalent to 4 mg ondansetron and superior to 25 mg dolasetron and placebo for the prevention of PONV. All treatments were safely administered and well tolerated.
Nitrous oxide reduces inspired oxygen fraction but does not compromise circulation and oxygenation during hemodilution in pigs
Authors: SCHOU H. , SÁ V. PEREZ DE , ROSCHER R. , LARSSON A.
Published: January 2009

Background: The use of nitrous oxide (N2O) during hemodilution has been questioned. Nitrous oxide reduces the inspired oxygen fraction (F1O2), depresses myocardial function and may reduce cardiac output (CO) and systemic oxygen delivery (DO2SY). The aim of this study was to evaluate the importance of the effects of nitrous oxide on systemic and myocardial circulation and oxygenation during extreme, acute, normovolemic hemodilution.

Methods: Ten midazolam‐fentanyl‐pancuronium anesthetized pigs were exposed to 65% N2O before and after extreme isovole‐mic hemodilution (hematocrit 33±1% and 10±1%, respectively). Systemic and myocardial hemodynamics, oxygen delivery and consumption and blood lactate were measured before (at FrO2 1.0 and 0.35) and during N2O exposure.

Results: Hemodilution caused an increase in CO from 137±43 to 229±32 ml kg‐1 min‐1 (P< 0.01), a decrease in systemic vascular resistance (from 42±14 to 20±4 mmHg L‐1 min‐1, P < 0.05), a decrease in mean arterial blood pressure (from 119±19 to 100±26 mmHg, P<0.05) and a decrease in DO2SY from 21.1 ±6.9 to 13.7±2.1 ml kg‐1 min‐1 (P < 0.01). Cardiac venous blood flow increased by 135% (P < 0.01) and cardiac venous saturation from 25±6 to 41±5% (P < 0.05). After hemodilution, changing FIO2 from 1.0 to 0.35 reduced arterial blood oxygen content from 59.4±3.7 to 52.3±5.1 ml L‐1 (P < 0.01), mixed venous saturation (SvO2) from 75±9 to 47±7% (P < 0.05) and DO2SY from 13.7±2.1 to 11.9+2.3 ml kg‐1 ‐ min‐1 (P < 0.05). Dissolved oxygen at F1O2=1.0 and F1O2=0.35 constituted 25.4±3.1% and 10.1 ±1.5%, respectively, of systemic oxygen delivery after hemodilution, compared with 10.7±1.2% and 3.9±0.5% before hemodilution (P < 0.01). Left ventricular oxygen delivery and consumption were unchanged. Exposure to N2O did not affect mean arterial blood pressure or systemic vascular resistance before or after hemodilution. After hemodilution during N2O‐exposure, CO and DO2SY decreased by 9% (P < 0.01 and P < 0.05, respectively), but no changes in SvO2, systemic oxygen uptake or arterial lactate were observed. The effect of N2O on myocardial oxygenation was similar before and after hemodilution; cardiac venous blood flow, left ventricular oxygen delivery and uptake decreased, but no animals showed left ventricular lactate production.

Conclusion: Nitrous oxide did not compromise systemic and myocardial circulation and oxygenation during acute normovolemic hemodilution in pigs. Possible adverse effects from the use of nitrous oxide during hemodilution seem to be related to a reduced FIO2, reducing the safety margin for systemic oxygen delivery.
Effects of halothane and isoflurane on left ventricular diastolic function during surgical stress in patients with coronary artery disease
Authors: HOULTZ E. , CAIDAHL K. , ADIN C. , GUSTAVSSON T. , RICKSTEN S.‐E.
Published: January 2009

Background: The effects of inhalation anesthetics on left ventricular (LV) systolic function are well documented, while the effects of these agents on LV diastolic function have mainly been evaluated in animal studies, with conflicting results.

Methods: We investigated the effects of halothane and isoflurane, when used to control the stress response to sternotomy in 33 patients with coronary artery disease (CAD). LV early diastolic relaxation and end‐diastolic stiffness were evaluated from mitral Doppler flow profiles, transesophageal two‐dimensional echocardiography, and central hemodynamic measurements. Measurements were performed a) after induction of anesthesia, b) after volume loading, c) prior to surgery and d) during surgery, 10 min after introduction of the inhalation anesthetic. The effects of the anesthetics on Doppler indices reflecting early diastolic relaxation, and on the left ventricular end‐diastolic pressure‐area (LVED P/A) relationship, were studied.

Results: When data obtained during surgical stress were compared to the control situation, we found an increase in the LV filling pressures in both groups, while only the isoflurane group showed an increase in heart rate. An increase in end‐systolic LV area and decreased fractional area change was present in the halothane group, while an increase in LV end‐diastolic area, and similar changes in the mitral Doppler indices (decreases of deceleration rate and time of early diastolic filling), indicating an impairment of early diastolic relaxation, was present in both groups. Isoflurane induced a displacement of the LVED P/A relationship leftwards from the baseline LVED P/A curve.

Conclusion: Both halothane and isoflurane impair early diastolic relaxation in patients with CAD, when used to control intraoperative surgical stress. In contrast to halothane, isoflurane induced a change in the LVED P/A relationship, suggestive of an increased LVED stiffness.
α1‐adrenoceptor stimulation is able to reverse halothaneinduced cardiac depression in isolated rat hearts
Authors: OKUYAMA T. , HOKA S. , OKAMOTO H. , KAWASAKI T. , YAMAURA K. , TAKAHASHI S.
Published: January 2009

Background:Stimulation of myocardial α1‐adrenoceptors has been shown to exert positive inotropic effects through a cyclic AMP‐independent mechanism. The purpose of this study was to examine if α1‐adrenoceptor stimulation is able to attenuate myocardial depression produced by exposure to halothane, and to test if α1‐adrenoceptor stimulation alters myocardial oxygen supply‐demand balance in hearts exposed to halothane.

Methods:The effects of phenylephrine were examined in 7 isolated perfused rat hearts. Variables measured were: heart rate, isovolumetric peak left ventricular pressure (LVP), LV dP/dt, coronary arterial flow, myocardial O2delivery (DO2), myocardial O2consumption (MVO2) and the ratio of DO2/MVO2. Each heart was exposed to phenylephrine cumulatively 0.1 μM, 0.3 μM, 1 μM and 3 μM under the administration of 1% halothane in the presence of propranolol 1μM.

Results:Halothane 1% decreased the heart rate by 9±3%, LVP by 37±3%, and LV dP/dt by 35±2%. Phenylephrine restored these decreases to the baseline levels. Phenylephrine maintained or further enhanced the reductions in coronary flow and DO2produced by halothane, resulting in a decrease in the DO2/ MVO2ratio.

Conclusion:α1adrenoceptor stimulation is capable of restoring direct cardiac depressant effects of halothane with a possible impairment of the oxygen supply‐demand balance.
Intermittent airway obstruction in a child caused by a cervical lipoblastoma
Authors: RASMUSSEN L. S. , KIRKEGAARD J. , KAASBØL M.
Published: January 2009

Severe intermittent airway obstruction was caused by a lipoblastoma in a 9‐month‐old boy. The tumor was located in the lower part of the neck and moved into the thoracic inlet causing compression of the trachea when he moved his head forwards. A tumor compressing or obstructing the trachea is infrequently the cause of airway obstruction in infants and children. Nevertheless, overlooking a tumor may have serious consequences when giving anesthesia due to the risk of difficulties with artificial ventilation depending on the localisation of the tumor. Every case of unexplained respiratory failure must be subject to a systematic approach that considers lung disease, broncho‐constriction, large airway obstruction, and external compression of the airway.
Testing for MH susceptibility
Authors: GRONERT G. A.
Published: January 2009

Two PROVOCATIVE papers by Ording et al. in this issue of Acta direct our thinking about MH testing in 3 ways. First, is the potential usefulness of added tests, e.g., 4‐chloro‐m‐cresol. Second, is a reconsideration of the role of genetic testing in MH, at present and in the future. Third, is unanticipated evidence demonstrating the need for world‐wide standardization of MH testing, thereby suggesting that differences in European (Eur) and North American (NA) testing protocols be resolved.
Does propofol reduce vomiting after strabismus surgery in children?
Authors: HAMUNEN K. , VAALAMO M. O. , MAUNUKSELA E.‐L.
Published: January 2009

Background: Previous studies have indicated that propofol anaesthesia may reduce the incidence of postoperative nausea and vomiting after strabismus surgery in children. This study was designed to investigate the incidence of vomiting after strabismus surgery at two different levels of propofol anaesthesia compared to thiopental/isoflurane anaesthesia.

Methods: Ninety ASA class I or II children, aged 5–14 yrs were randomly assigned to one of three groups: Group T/I (n=30) induction with 5 mg kg‐1 of thiopental and maintenance with isoflurane, group P5 (n=31) induction with propofol 2 mg kg‐1, maintenance with propofol infusion 5 mg kg‐1 h‐1 or group P10 (n=29) induction with propofol 2 mg kg‐1, maintenance with propofol 10 mg kg‐1 h_I. All received glycopyrrolate, vecuronium, fentanyl and controlled ventilation with O2/N2O 30/ 70. Ketorolac i.v. was given to prevent postoperative pain. If additional analgesia was needed, ibuprofen/acetaminophen or buprenorphine was given according to clinical need.

Results: There were no differences between study groups with respect to age, weight, history of previous anaesthesia or emesis after previous anaesthesia, duration of anaesthesia, surgery or sleep after anaesthesia, or number of muscles operated. The incidence of vomiting was 37%, 29% and 28% in groups T/I, P5 and P10, respectively. There were no statistically significant differences between the three groups in the incidence of vomiting. The median age of patients who vomited was 7.5 (range 5.0–13.7) yrs while the median age of the patients who did not vomit was 9.1 (range 5.0–14.0) yrs (P < 0.01).

Conclusion: In the present study, propofol anaesthesia compared to thiopental/isoflurane anaesthesia did not reduce the incidence of vomiting following strabismus surgery in children.
Intubating conditions provided by propofol and alfentanil ‐ acceptable, but not ideal
Authors: HARSTEN A. , GILLBERG L.
Published: January 2009

Background: The use of muscle relaxants to facilitate intubation is associated with several side effects regardless of whether depolarizing or non‐depolarizing drugs are used. In the present study we compared the intubating conditions, haemodynamic responses and changes in oxygen saturation following induction with alfentanil and propofol or alfentanil, thiopental and suxamethonium.

Methods: Eighty patients (ASA I or II) were in a double‐blind manner assigned to receive either of the two induction methods. Intubating conditions were assessed on the basis of jaw relaxation, ease of insertion of the endotracheal tube and coughing on intubation. Heart rate, systolic arterial pressure and oxygen saturation were monitored throughout the procedure.

Results: The use of alfentanil and propofol resulted in significantly lower scored intubation points. Systolic arterial pressure decreased and heart rate increased significantly in the alfentanil‐thiopental‐suxamethonium group as compared to the alfentanil‐propofol group. There were no significant changes in oxygen saturation.

Conclusion: The results show that propofol and alfentanil in combination provides haemodynamic stability and unaltered oxygen saturation but less optimal intubating conditions.
Recovery characteristics of sevoflurane‐ or propofol‐based anaesthesia for day‐care surgery
Authors: RÆDER J. , GUPTA A. , PEDERSEN F. M.
Published: January 2009

Background: Sevoflurane has a low blood‐gas partition coefficient resulting in a rapid recovery. Few studies have examined the maintenance and recovery characteristics of sevoflurane compared with propofol in a standardized outpatient population.

Methods: The study was a multicentre study performed in 10 centres. One hundred and sixty‐nine elective outpatients due for knee‐arthroscopy received 100 mg diclofenac rectally as pain prophylaxis prior to induction of general anaesthesia with fentanyl 1.0–1.5 μg/kg+propofol 2.0–2.5 mg/kg iv. Anaesthesia was maintained with 60% nitrous oxide in oxygen through a laryngeal mask and continuous administration of either: sevoflurane (group S) or propofol infusion (group P) in order to maintain stable haemodynamics. Data of postoperative function and side‐effects were collected in a double‐blind design, including a patient interview after 24 h.

Results: The sevoflurane patients had a significantly faster emergence from anaesthesia, with response to commands at 6.9±0.4 min versus 8.2±0.4 min in the propofol group (P < 0.05, mean±SD). At 15 min after surgery, group S had a better score in the digit symbol substitution test and felt less confused in a visual analogue scale test compared with group P (P<0.05). Peroperative bradycardia, nausea and vomiting and late postoperative dizziness were more common in group S. In the sevoflurane group, 32% had nausea or vomiting in the 24 h observation period compared with 18% for propofol (P < 0.05). There was no difference between group S and group P in postoperative pain, eligibility for recovery room discharge (75±12 versus 70±11 min) or home‐readiness (155±12 versus 143±11 min).

Conclusion: Maintenance of anaesthesia with sevoflurane results in a more rapid emergence, but a higher incidence of nausea and vomiting compared with propofol. The side‐effects were minor in our study, and did not result in any difference in time to discharge from the recovery ward or the hospital.
Impact of autotransfusion after coronary artery bypass grafting on oxygen transport
Authors: SCHMIDT H. , FØSGAARD S. , MORTENSEN P. E. , JENSEN E.
Published: January 2009

Background: Autotransfusion of shed mediastinal blood after coronary artery bypass grafting (CABG) has been shown to reduce the requirement for allogeneic blood. We have previously demonstrated in non‐randomized studies that the oxygen capacity of shed mediastinal blood is similar to the patient's circulating blood and better than stored allogeneic blood. Therefore, we wanted to examine the influence of autotransfusion of shed mediastinal blood on oxygen transport capacity in patients undergoing CABG.

Methods: A prospective, randomized, controlled study involving 120 patients having elective, uncomplicated CABG was performed. The autotransfusion group received transfusion of shed mediastinal blood for 18 h. Both groups received allogeneic red cells if their hemoglobin concentration decreased below 5 mmol/L. Red blood cell 2, 3‐diphosphoglycerate (2, 3‐DPG) was measured preoperatively and at intervals up to the hospital discharged. Hemodynamic measurements as well as blood gas and hemoglobin measurements from samples of arterial and mixed venous blood were used for calculation of oxygen transport capacity.

Results: During the autotransfusion period only 2 patients (4%) in the autotransfusion group required allogeneic blood compared to 11 patients (20%) in the control group. The 2, 3‐DPG levels in the autotransfusion group were unchanged before and after autotransfusion (4.4 vs. 4.3 umol/ml erythrocyte). In the control group, 2, 3‐DPG levels decreased from 4.3 to 3.9 umol/ ml erythrocyte during the same period. There were no differences in the other measured parameters for oxygen transport capacity between the groups.

Conclusion: Autotransfusion of shed mediastinal blood conserves the 2, 3‐DPG level of the red blood cells, while transfusion of stored blood leads to a decrease in 2, 3‐DPG levels. Autotransfusion had no effect on hemodynamic parameters, oxygen delivery or oxygen extraction.
Nasal mucosa inflammation induced by oxygen administration in humans
Authors: CAPELLIER G. , ZHANG Z. , MAHEU M. F. , POINTET H. , RACADOT E. , KANTELIP B. , REGNARD J. , BARALE F.
Published: January 2009

Background: The effect of oxygen toxicity in human airways is still poorly documented. We prospectively evaluated the inflammatory reaction induced by nasal oxygen exposure in an experimental setting.

Methods: Healthy subjects without nasal symptoms were exposed to high FIO2 during 5 h. Oxygen was delivered from a tank at a flow of 41/min to one nostril of each subject and both nostrils were studied. Mucociliary clearance was measured as saccharine nasal transit time (SNTT). Nasal lavage was performed with 5 ml normal saline and the fluid recovered was processed for cytology and measurements of cytokines concentrations: TNFα, IL‐6, IL‐8 and soluble ICAM‐1. Under local anaesthesia, biopsies were performed for immunochemistry and electron microscopy.

Results: After oxygen exposure mucociliary clearance decreased and SNTT increased from 16 [9–21] to 20.5 [14–32] min (median and extremes; P < 0.1). In the lavage fluid, concentration of IL‐6 was higher in the oxygen‐exposed nostril (40.5 [11–128] pg/ml) than in the non‐exposed one (7 [0–34] pg/ml; P < 0.05). There was also a trend for a higher IL‐8 in the exposed than in the non‐exposed nostril, (respectively 501 [214–587] pg/ml and 214 [122–616] pg/ml, P < 0.08), and for a higher number of polymorphonuclear cells in exposed nostril. In the mucosal biopsies substance P was not found, but ICAM‐1 expression was higher in the mucosa and submucosa of the exposed nostrils where mast cells were also more abundant and showed piecemeal degranulation.

Conclusion: In summary, we found clinical, functional and biological evidence of ongoing nasal inflammation following high FIO2 inhalation for 5 h. Since the histology and behaviour of nasal and bronchi mucosa are very similar, the same inflammatory events are likely to be occurring in the bronchi upon high concentrations of inhaled oxygen.
Survey of postoperative analgesia following ambulatory surgery
Authors: RAWAL N. , HYLANDER J. , NYDAHL R‐A. , OLOFSSON I. , GUPTA A.
Published: January 2009

Background: The quality of pain relief during the first 48 hours following ambulatory surgery has been poorly documented. This questionnaire study was performed to evaluate the nature and severity of pain after the patient leaves the hospital.

Methods: 1100 patients in the age group 5–88 years who underwent ambulatory surgery during a period of 6months were asked to complete a questionnaire 48 h after the end of the operation. In thecase of children, parents were asked to complete a similar questionnaire. The questions were related to pain experienced during the first 48 h after surgery and to the nature andseverity of postoperative complications.

Results: A total of 1035 out of the 1100 patients returned the questionnaire, 94.1%. Overall the majority (65%) of patients had only mild pain at home; however, patients undergoing certain types of surgery had moderate‐to‐severe pain: inguinal hernia surgery (62% patients), orthopaedic surgery (41%), hand surgery (37%) and varicose vein surgery (36%). In these patients the severity of pain did not decrease during the 2‐day study period. About 10% patients had more severe pain than they had anticipated, and 20% had difficulty in sleeping at night due to severe pain. Despite this, over 95% of patients were satisfied with man‐agement of postoperative pain. Nausea (20%), tiredness (20%) and vomiting (8%) were the commonest complications reported during the first 48 h. A significant association was found between the administration of a general anaesthetic and the incidence of nausea postoperatively. A large number of patients were alone at home after the operation (28.4%); some (3.8%) had no access to a relative or friend in case of need.

Conclusion: Our results show that about 35% of day‐surgery patients experience moderate‐to‐severe pain at home in spite of analgesic medication. About 20% of patients had sleep problems due to severe pain. However, only 5% of patients were dissatisfied. Better analgesic techniques are necessary for patients undergoing certain types of surgery. Patient information and follow‐up routines need to be improved.
Perioperative magnesium infusion and postoperative pain
Authors: WILDER‐SMITH C. H. , KNØPFLI R. , WILDER‐SMITH O. H. G.
Published: January 2009

Background: NMDA receptor activation is considered one of the mechanisms involved in postoperative pain and hypersensitivity. Magnesium is the physiological blocker of the NMDA‐receptor‐complex‐associated calcium ionophore. The aim of this study was to determine if a pre‐, intra‐ and postoperative infusion of magnesium would reduce postoperative pain.

Methods: In a prospective, randomised, double‐blinded and placebo‐controlled study, 24 patients undergoing elective hysterectomy in standardised general anaesthesia received a 5 h infusion of either placebo or magnesium laevulinate (initial bolus 8 mmol: then 8 mmol/h) starting with induction of anaesthesia. Postoperative analgesia was by PCA morphine for the first 48 h and patients were followed for 5 d with regular assessments of pain and side‐effect scores.

Results: Overall, pain scores were similar with magnesium and placebo infusion, although patients in the magnesium group experienced more episodes of severe or unbearable pain (pla‐cebo=6%, magnesium=16%, P=0.02). Median pain scores were higher in the magnesium group only at 3 h postoperatively (P= 0.04): afterwards there were no significant differences. Except for the first postoperative hour (placebo=12.8±4.7 mg, mag‐nesium=9.3±3.2 mg, P=0.04), cumulative morphine consumption was similar. Gastrointestinal complication rates and patient satisfaction were similar in both groups.

Conclusions: Perioperative magnesium infusion does not improve postoperative analgesia. At the doses used in this study, the use of magnesium is associated with short‐term decreases in postoperative analgesia.
Preoperative hypnosis reduces postoperative vomiting after surgery of the breasts
Authors: ENQVIST B. , BJÖRKLUND C. , ENGMAN M. , JAKOBSSON J.
Published: January 2009

Background:Postoperative nausea and vomiting (PONV) after general anesthesia and surgery may have an incidence as high as 70% irrespective of antiemetic drug therapy. The use of preoperative hypnosis and mental preparation by means of an audio tape was investigated in the prophylaxis of nausea and vomiting before elective breast reduction surgery. Similar interventions have not been found in the literature.

Methods:Fifty women were randomized to a control group or a hypnosis group; the latter listened to an audio tape daily 4–6 days prior to surgery. A hypnotic induction was followed by suggestions as to how to relax and experience states incompatible with nausea and vomiting postoperatively (e.g. thirst and hunger). There was a training part on the tape where the patients were asked to rehearse their own model for stress reduction. Premedication and anesthetic procedures were standardized.

Results:Patients in the hypnosis group had significantly less vomiting, 39% compared to 68% in the control group, less nausea and less need of analgesics postoperatively.

Conclusions:Preoperative relaxation and/or hypnotic techniques in breast surgery contribute to a reduction of both PONV and postoperative analgesic requirements.
Topographical analysis of the EEG effects of a subconvulsive dose of lidocaine in healthy volunteers
Authors: DETSCH O. , ERKENS U. , JACOFSKY U. , THIEL A. , KOCHS E. , HEMPELMANN G.
Published: January 2009

Background:The purpose of the present study was to assess the effects of intravenous lidocaine on spatial changes of electroen‐cephalographic power and on psychomotoric status in conscious volunteers.

Methods:In 11 healthy volunteers lidocaine (2‐min bolus, 100 mg; 15‐min infusion, 40 μg kg‐1min‐1) or placebo were given intravenously in a randomized, single‐blinded, two‐way crossover study. Haemodynamics and lidocaine plasma concentrations were measured at baseline and within a period of 30 min following bolus injection. Vigilance and emotional status were tested using visual analogue scales (VAS). Toxic CNS effects were evaluated by a questionnaire. The raw EEG (17 leads, reference Cz) and computed power spectra were continuously recorded.

Results:The chosen lidocaine dosage led to nearly constant plasma concentrations (unbound lidocaine 2.5 min and 15 min after bolus 0.36±0.14 μg/ml and 0.30±0.06 μg/ml, respectively [mean±SD]). The placebo caused no symptoms, changes in VAS‐scores or EEG‐parameters. Lidocaine induced pronounced subjective symptoms and significant increases in delta activity for 15 min, most dominant at the frontotemporal and occipital leads (max. +219% O1). Frontal and occipital beta1 and beta2 power (max. +131% and +124% at O1, respectively) was immediately increased after the bolus injection. No EEG changes occurred at central region Cz, and no interhemispheric EEG differences were noted. Theta, alphal, and alpha2 power remained unchanged.

Conclusion:The current data demonstrate simultaneous changes in psychomotoric status as well as delta and beta spectral power during lidocaine infusion. These data could be an indication that the pronounced frontotemporal and occipital EEG changes are the electroencephalographic expression of subjective sensations.
Intravenous versus intraperitoneal morphine before surgery to provide postoperative pain relief
Authors: KALMAN S. H. , JENSEN A. G. , NYSTRÖM P. O. , EINTREI C.
Published: January 2009

Background:Opioid receptors have been demonstrated on peripheral afferent nerves throughout the body. The aim of the present study was to compare the effects of intravenous and intraperitoneal administration of morphine with regard to pain, postoperative morphinerequirement, and recovery after major abdominal surgery, and to describe the pharmacokinetics of intraperitoneal morphine in humans.

Methods:In a double‐blind manner, 30 patientsscheduled for major abdominal surgery were randomized to either 50 mg of morphine intravenously (IV) or 50 mg of morphine intraperitoneally (IP) before operation. Pain was measured on a visual analogue scale and morphine requirements were registered for 3 days. Recovery was measured as time to oral intake of food, time to flatulence and days in hospital. Plasma morphine, mor‐phine‐3‐glucuronide, and morphine‐6‐glucuronide concentrations were determined during the first 4 h after morphine administration.

Results:During the first postoperative hours there was less pain at rest (P=0.02) and on coughing (P=0.004) in the intravenous group. The requirementof additional morphine (P=0.016) was lower in the intravenous group during the first postoperative day. No major differences in recovery were seen. The plasma concentrations of morphine measured as area under the curve (AUC) during the first 4 h were similar, but the intravenous group showed significantly higher concentrations of the active metabolite morphine‐6‐glucuronide, (P=0.016), indicating a difference in pharmacokinetics after intraperitoneal compared to intravenous administration of morphine.

Conclusion:Intraperitoneal administration of 50 mg of morphine before major abdominal surgery is less efficient in reducing pain and postoperative morphine requirements than thesame amount of morphine given intravenously.