bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of inhalation inductions with xenon and sevoflurane
Authors: NAKATA Y. , GOTO T. , MORITA S. 
Published: January 2009

Background: Xenon is an odorless gas with low blood‐gas solubility coefficient and without occupational and environmental hazards. This investigation was performed to evaluate the speed of induction, and respiratory and cardiovascular reactions to inhalation induction with xenon compared to an equianesthetic concentration of sevoflurane.Results: Compared to equianesthetic sevoflurane, xenon produced a faster induction of anesthesia (14759 versus 71221 s, respectively) with smaller decreases in respiratory rate, tidal volume and minute ventilation. Both agents showed comparable cardiovascular stability and oxygen saturation during induction. One patient in the sevoflurane group had breath‐holding and movements of extremities and another had only breath‐holding. No patients in the xenon group experienced any complications.Conclusion: Xenon produced a faster induction of anesthesia without any complications than sevoflurane. Xenon had smaller decreases in tidal volume and respiratory rate during induction than sevoflurane. Xenon might offer an alternative to sevoflurane for an inhalation induction.Method Twenty‐four adult ASA 1–2 patients premedicated with 0.05 mg/kg of midazolam were instructed to take vital capacity breaths of 1 minimum alveolar concentration (MAC) of either xenon or sevoflurane until they lost consciousness. Induction time, total ventilatory volume, tidal volume, respiratory rate, minute ventilation, end‐tidal MAC fraction, cardiovascular parameters and oxygen saturation were recorded. The patients were interviewed on the following day to evaluate their acceptability rating of the inhalation inductions.
Laryngeal mask bite blocks ‐ rolled gauze versus Guedel airway
Authors: KELLER C. , SPARR H. J. , BRIMACOMBE J. R. 
Published: January 2009

Background: Biting on the silicone tube and pilot balloon of the laryngeal mask airway (LMA) may obstruct or damage them with the teeth and a bite block is recommended. The recommended bite block is a wad of gauze swabs rolled into a cylindrical shape and placed alongside the LMA. It is considered that this avoids irritating the posterior pharyngeal wall and damage to teeth whilst supporting the LMA tube when taped to it. The Guedel airway is commonly used as a bite block with the tra‐cheal tube and many anaesthetists also use it with the LMA. The aim of the following study was to compare rolled gauze swabs with a Guedel airway as a bite block for the LMA.Methods: We compared the Guedel airway with rolled gauze swabs as a bite block for the laryngeal mask airway (LMA) in 120 ventilated patients in whom cuff pressures were limited to 5.87 kPa (60 cm H20) and anaesthesia management was standardised.Results: In the Guedel airway group, there was a higher incidence of ventilatory problems (0 vs 4, P < 0.05), bleeding (0 vs 8, P < 0.01), hoarseness (0 vs 4, P0.05) and sore throat (2 vs 12, P < 0.01).Conclusion: 1. The Guedel airway is an unsuitable bite block for the LMA. 2. Cuff pressure limitation is compatible with adequate ventilation. 3. The combination of LMA and Guedel airway probably prevents either from sitting in the correct anatomical position.
Autoregulation and vasodilator responses by isoflurane and desflurane in the feline renal vascular bed
Authors: SUNDEMAN H. , BIBER B. , RANER C. , WINSÖ O. 
Published: January 2009

Background: Inhalational anesthetics have agent‐specific effects on the renal circulation. This study investigated renal vasodilator responses produced by either autoregulation, 0.8% isoflurane (ISO) or 3.5% desflurane (DES).Methods: We measured systemic mean arterial pressure (MAP‐SYST; axillary artery), renal blood flow (QREN; perivascular ultrasound) and central venous pressure (CVP) in normoventilated cats (n=8) during basal chloralose anesthesia (control) and after the addition of IS0 and DES. Renal mean arterial pressure (MAPREN) was controlled by an aortic clamp. QREN was measured at pre‐set MAPREN levels of 50, 70 and 90 mmHg. Renal vascular resistance (RREN) was derived.Results: When MAPREN was artificially restrained from 13325 mmHg to 90 mmHg during control, RREN decreased by 35% and no significant change in QREN was observed, reflecting an intact autoregulation. RREN levels during IS0 or DES at stages with unrestrained MAPREN (9526 and 10229 mmHg, respectively), were not significantly different from RREN at 90 mmHg during control. When MAPREN was artificially decreased below 90 mmHg, QMN decreased in a similar fashion among control and ISO/DES sequences. The autoregulatory capacity was not significantly different among these sequences. Between 90–70 mmHg, the autoregulatory capacity was reduced and not demonstrable below 70 mmHg.Conclusion: The renal autoregulatory capacity was not attenuated by either IS0 or DES. These agents produced equipotent renal vasodilation, which was not more powerful than that produced by autoregulation alone. The renal vasorelaxant effects of IS0 and DES may therefore to a substantial extent be attributable to autoregulation.
Vectorcardiographic changes during laparoscopic cholecystectomy may mimic signs of myocardial ischaemia
Authors: GANNEDAHL P. , ODEBERG S. , LJUNGQVIST O. , SOLLEVI A. 
Published: January 2009

Background: Laparoscopic surgery involves the use of intra‐ab‐dominal carbon dioxide insufflation (pneumoperitoneum). The increased intra‐abdominal pressure causes marked haemodyn‐amic changes, which may influence electrocardiographic monitoring. The aim of the present study was to elucidate the influence of pneumoperitoneum on vectorcardiographic recordings.Methods: Vectorcardiographic changes (QRS vector difference= QRSVD, QRS loop area, QRS magnitude, ST vector magnitude, spatial ST vector change) were recorded continuously applying computerized vectorcardiography in 12 anaesthetised cardio‐vascularly healthy patients, scheduled for laparoscopic cholecystectomy.Measurements were made before and during pneumoperitoneum in three different body positions (supine, Trendelenburg and reversed Trendelenburg), also employing transesophageal echo‐cardiography and invasive blood pressure monitoring. Results: Pneumoperitoneum significantly increased QRSVD, in parallel with an enlargement in loop area and magnitude. The magnitude was significantly increased in the transversal and frontal planes and there was a tendency to increase the magnitude in the sagittal plane. The increase in QRS‐VD reached levels previously associated with the development of myocardial ischaemia in patients with coronary artery disease. The ST‐variables were not changed by the pneumoperitoneum. The positional changes also influenced QRSVD significantly.Conclusions: When computerized vectorcardiography is used for ischaemia monitoring during pneumoperitoneum, the ST‐variables seem reliable. However, vectorcardiographic QRS changes should be interpreted with caution, as the QRS alterations found during pneumoperitoneum mimic the changes seen during myocardial ischaemia.
Contradictory effects of dopamine at 32°C in pigs anesthetized with ketamine
Authors: ROSCHER R. , INGEMANSSON R. , WETTERBERG T. , ALGOTSSON L. , SJÖBERG T. , STEEN S. 
Published: January 2009

Background: In critically ill patients who were surface cooled to 332C, we have observed that dopamine sometimes causes a substantial decrease in blood pressure. The present study was designed to compare the effects of dopamine in normothermia to those seen after surface cooling to 32C.Methods: Seven pigs with a mean body weight of 21 kg were anesthetized with ketamine and muscle relaxation was induced with pancuronium. They were mechanically ventilated and given dopamine infusions (5 and 12 μg · kg‐1 min‐1) in normothermia and after surface cooling by cold water immersion to a central blood temperature of 320C (range 31.6–32.6C).Results: In normothermia, dopamine at a dose of 5 μg · kg‐1 min‐1 increased mean arterial blood pressure (MAP) by 16% (P < 0.01) and cardiac output (CO) by 9% (P=0.051); at 12 μg kg‐1 min‐1 dopamine increased MAP by 26% (P < 0.01) and CO by 18% (P < 0.01). In hypothermia, MAP and CO did not change at an administration rate of 5 μg kg‐l · min‐1; at 12 μg · kg‐1 min‐1 CO was unchanged but MAP was significantly reduced by 15% (P < 0.01).Conclusion: Dopamine increased CO and MAP in normothermia but not at 32C, where there was even a significant reduction of MAP in this porcine model.
Preoperative adjuvant epidural tramadol: the effect of different doses on postoperative analgesia and pain processing
Authors: Wilder‐Smith C. H. , Wilder‐Smith O. H. G. , Farschtschian M. , Naji P. 
Published: January 2009

Background:Tramadol is an analgesic with combined opioid agonist and monoamine reuptake blocker properties, which may be useful as a perioperative analgesic and antinociceptive adjuvant.Methods:The dose‐dependent effects of adjuvant preoperative epidural tramadol on postoperative analgesia (pain scores and patient‐controlled analgesia (PCA) use) and pain processing (heat pain thresholds) were prospectively studied in a double‐blind, randomised, placebo‐controlled 5‐day trial. Forty patients undergoing knee or hip surgery received anaesthesia with epidural lidocaine and epidural tramadol 20, 50 or 100 mg or placebo as a preoperative adjuvant. Postoperative analgesia was by intravenous PCA tramadol in all patients.Results:Postoperative pain scores were similar in all groups. The time to first PCA use was shorter, the total dose and duration of PCA use greater, and side‐effects more common with 20 mg tramadol than with 100 mg or placebo (P<0.05). There were no differences in PCA doses required or side‐effects between the tramadol 100 mg and placebo treatment groups. Heat pain tolerance thresholds were increased with 100 mg tramadol at 48 h postoperatively compared to baseline and placebo (P= 0.01).Conclusions:Preoperative adjuvant epidural tramadol does not improve postoperative analgesia after lidocaine epidural anaesthesia compared to placebo. Tramadol 20 mg results in anti‐analgesia and increased side‐effects. While tramadol 100 mg depresses postoperative pain‐processing, as measured by heat pain tolerance thresholds, this is not reflected in improved clinical pain measures.
Improved oxygenation using the prone position in patients with ARDS
Authors: Flaatten H. , Aardal S. , Hevrøy O. 
Published: January 2009

Background: The prone position is known to increase oxygen uptake in patients with Adult Respiratory Distress Syndrome (ARDS).Methods: In this clinical study from 1995–96, 14 ARDS patients with severe respiratory failure were treated for at least 1 h in the prone position. Responders, defined as having more than 10% increase in PaO2/FiO2 ratio from baseline after 1 h, were treated at least 6 h in the prone position.Results: 11 patients responded during the first period of the prone position (primary responders). Two of the 3 non‐responders were turned prone a second time with increase in the PaO2FiO2 ratio (secondary responders). Mean PaO2FiO2 ratio (mean±SEM) in the supine position was 11.7±0.8 kPa, increasing to 16.6±1.8 kPa and 18.0±1.4 kPa after 1 and 6 h respectively (P=0.009). Mean time spent in the prone position was 69 h (range 3–256 h), and mean ventilatory time was 17 d (3–52 d). The mortality in this subgroup of our patients with ARDS was 42%, compared to 58% in 19 patients not turned prone in the same period.Conclusions: The prone position together with PEEP appears to improve ventilation‐perfusion matching. The prone position is simple, effective and readily available and could be used early in most patients with ARDS.
Reduced CO2‐elimination during combined high‐frequency ventilation compared to conventional pressure‐controlled ventilation in surfactant‐deficient piglets
Authors: Lichtwarck‐Aschoff M. , Zimmermann G. J. , Erhardt W. 
Published: January 2009

Background: Combined high‐frequency ventilation (CHFV) combines a conventional low‐frequency component with superimposed high‐frequency jet pulses. The intention is to overcome the limited CO2‐elimination of high‐frequency ventilation, and to decrease airway pressures and enhance hemodynamic performance by reducing the conventional component. The present study was performed to compare the effects of conventional continuous positive‐pressure ventilation (CPPV) on gas exchange, airway pressures and cardiac output to those of CHFV at matched minute volume (MV) and mean airway pressure (MPAW).Methods: Sixteen anaesthetised piglets with lavage‐induced surfactant deficiency were ventilated with CPPV, with positive end‐expiratory pressure (PEEP) set to obliterate the lower inflection point of the inspiratory pressure‐volume loop. This setting was compared to CHFV during which 50% of the total MV was applied as superimposed jet pulses of 20 Hz at otherwise unchanged settings, and to CPPV at a PEEP level which was reduced (CPPVred) until MPAW matched MPAW during CHFV. Gas exchange, airway pressures and hemodynamics were measured after the ventilatory setting had been applied for 20 min.Results: MPAW decreased from (median) 2.7 kPa with CPPV to 2.4 kPa with CHFV (P≤0.05). Peak inspiratory pressure was 3.6 kPa with CPPV, 3.2 kPa with CHFV, and 3.2 kPa with CPPVred (P≤0.05 for differences to CPPV), respectively. PaCO2 was comparable during CPPV (5.9 kPa), CPPVred and CHFVCO2, while it increased during CHFV (6.8 kPa, (P≤0.05)). Cardiac output did not differ significantly between the settings.Conclusions: In the porcine lavage model, CO2‐elimination is reduced during CHFV compared to CPPV at matched minute volume. At matched mean airway pressure, CHFV fails to reduce peak inspiratory airway pressure and to improve hemodynamic performance compared to CPPV.
Plasma catecholamines and haemodynamic changes during pneumoperitoneum
Authors: Myre K. , Rostrup M. , Buanes T. , Stokland O. 
Published: January 2009

Background: Insufflation of CO2 into the abdomen is used during all kinds of laparoscopic operations. The procedure elicits haemodynamic and hormonal responses. The reports on sympathetic responses to laparoscopic surgery have been conflicting. However, few studies have assessed sympathetic and haemodynamic responses to CO2 insufflation per se, eliminating possible effects of intubation, skin incision, surgical manipulation and positioning of the body. No studies have measured both venous and arterial plasma catecholamines, the latter being a more sensitive indicator of sympathetic activity. In the present study, we hypothesised an increased sympathetic activity during pneumoperitoneum and an association between haemodynamic and sympathetic responses.Methods: Plasma adrenaline and noradrenaline from the radial artery and superior vena cava were measured immediately before and 10 min after abdominal insufflation of CO2 in 11 subjects. Haemodynamics were monitored invasively.Results: During pneumoperitoneum arterial plasma noradrenaline increased from 155 (106, 209) pg/ml (median, lowest and highest quartile) to 283 (188, 378) pg/ml (P=0.003), while there were no changes in arterial plasma adrenaline. The calculated arterial‐superior vena cava difference in plasma noradrenaline did not change, indicating no increased sympathetic activity in the drainage area of the superior vena cava. Heart rate and cardiac index were unchanged, while total peripheral resistance and mean arterial blood pressure increased (P=0.002). The changes in arterial plasma noradrenaline were closely related to the changes in total peripheral resistance (r=0.69, P=0.01).Conclusions: Plasma noradrenaline increases during pneumoperitoneum and is associated with changes in total peripheral resistance. Plasma adrenaline is unchanged and there is no evidence of increased sympathetic outflow to the drainage area of the superior vena cava. Thus, the increase in plasma noradrenaline may be due to more local activation of the sympathetic nervous system, probably somewhere from the drainage area of the inferior vena cava.
Effects of desflurane, sevoflurane and halothane on postinfarction spontaneous dysrhythmias in dogs
Authors: Novalija E. , Hogan Q. H. , Kulier A. H. , Turner L. H. , Bosnjak Z. J. 
Published: January 2009

Background: Although desflurane (DES) and sevoflurane (SEV) have desirable features for use in patients with coronary artery disease, their effects on ventricular dysrhythmias following infarction are less known. We therefore examined the effects of DES and SEV upon spontaneous postinfarction ventricular dysrhythmias in dogs, and compared those effects to the well‐established antidysrhythmic effects of halothane (HAL) in this model.Methods: After institutional approval, the left anterior descending coronary artery was ligated in 16 adult mongrel dogs during isoflurane anesthesia. All dogs developed acute myocardial infarction and severe ventricular tachydysrhythmias. Twenty‐two hours after infarction, dogs were anesthetized at 1.5 MAC with desflurane (10.8%) followed by sevoflurane (3.5%) in the treatment group (n=10), or halothane (1.3%) in the other group (n=6). Anesthetic gases were allowed to equilibrate for at least 20 min at each end‐tidal concentration. At this time, the ECG was recorded for 9 min and evaluated for the number of ventricular ectopic and sinoatrial beats and summed duration of ventricular tachycardia.Results: DES and SEV reduced the average rate of total ventricular ectopic beats by 40 ±4% and 42 ±4%, respectively. HAL decreased total ventricular ectopic rate by 59 ±6% and 62 ±5% after durations of anesthesia comparable to DES and SEV, respectively. Decreases in dysrhythmia in the presence of DES and SEV were significantly smaller than those produced by HAL after a comparable total duration of anesthesia.Conclusions: DES and SEV inhibit spontaneous postinfarction ventricular dysrhythmias, although attenuation of dysrhythmias was smaller than the inhibition during comparable doses of HAL.
Transient radicular irritation with intrathecal plain lignocaine
Authors: Henderson D. J. , Faccenda K. A. , Morrison L. M. M. 
Published: January 2009

Background: The aetiology of the syndrome known as transient radicular irritation (TRI) has generated much interest.Method: A 50‐year‐old woman had right knee arthroscopy performed under spinal anaesthesia with 1% plain lignocaine. Result: At home, on the night of the procedure, she was woken by severe, bilateral cramp‐like pain in both buttocks radiating to her thighs. Neurological examination of her lower limbs, the next morning, was entirely normal. The pain lasted for 36 h and a full recovery was made.Conclusions: This case of transient radicular irritation occurred in a patient given 40 mg of subarachnoid lignocaine (the lowest dose of isobaric preservative‐free lignocaine reported thus far that has been associated with these symptoms). Her operation was performed in the supine position. The lack of confounding factors (hyperbaricity, high concentration solution, preservatives, lithotomy position) suggests lignocaine as a possible cause, yet current theories do not fully explain the aetiology of transient radicular irritation. Results from large‐scale epidemiological studies will hopefully provide insight into the cause of this problem.
Intraoperative monitoring with somatosensory evoked potentials in carotid artery surgery ‐ less reliable in patients with preoperative neurologic deficiency?
Authors: Linstedt U. , Maier C. , Petry A. 
Published: January 2009

Background: In a retrospective analysis of intraoperative somatosensory evoked potential (SEP) results during carotid artery surgery we found some cases with postoperative neurologic deficits, surprisingly without significant SEP changes.Methods: Median nerve SEP were monitored as usual. Indication for selective shunting was a complete loss of amplitude N20/P25 in the first period of the investigation, later on a 50% reduction, or a prolongation of the central conduction time (CCT) of about 1.5 ms after cross‐clamping. Anaesthesia was maintained with isoflurane in N2O/O2, fentanyl and atracurium.Results: Over a 3‐year period 146 patients were monitored. Indications were: transient ischaemic attacks (TIA) (n=51), stroke (n=23), stroke with residuals (n=39), asymptomatical stenosis (n=29), subclavian steal syndrome (n=4). Twenty‐four patients received an intraluminal shunt following SEP alterations. Post‐operatively, 5 patients (3.4%) had symptoms of intraoperative brain ischaemia (stroke n=2, TIA n=3), 4 of them showing only minor intraoperative SEP alterations; 1 received a shunt because of CCT prolongation. Four of these 5 patients had cerebral neurologic deficiency preoperatively.Conclusion: Since some authors have found a 100% sensitivity of intraoperative SEP, it is remarkable, that 1 patient with postoperative stroke and 3 patients with TIA had no significant SEP changes intraoperatively. We suppose there was an association with preoperative neurological deficits resulting from previous strokes. In such cases, regional critical ischaemia may apparently occur outside the sensory pathway monitored with SEP.
A comparison of the effects of fentanyl and propofol on left ventricular contractility during myocardial stunning
Authors: Ross S. , Munoz H. , Piriou V. , Ryder W. A. , Foex P. 
Published: January 2009

Background: The intravenous anaesthetic propofol has been shown to possess free radical scavenging activity and calcium channel blocking effects in a number of in vitro models. We decided to compare the effects of propofol with those of fentanyl on myocardial contractility during and after ischaemia to determine whether propofol could protect the heart and improve recovery of ventricular contractile function in open‐chested dogs.Methods: Twenty adult beagles were acutely instrumented, under halothane anaesthesia, to measure ECG; aortic, left ventricular pressures; cardiac output; coronary flow; and segmental lengths in the regions perfused by the left anterior and left circumflex coronary arteries. After surgery and a stabilisation period halothane anaesthesia was terminated and fentanyl (100 μg. kg‐1 bolus followed by 2 μ.kg‐1·min‐1 infusion; n=10) or propofol (5 mg. kg‐1 bolus followed by 0.3 mg· kg‐1 min‐1 infusion; n=10) anaesthesia commenced. After a stabilisation period the LAD coronary artery was occluded for 10 min and then reperfused for 3 h. Measurements were taken throughout the protocol.Results: We found no significant difference in recovery of contractile function between propofol and fentanyl as assessed by normalised preload recruitable work area (50±10 vs 47±16%), normalised systolic shortening (36±12 vs 48±14%) and peak left ventricular dP/dt (1665±276 vs 1846±151 mmHg.s‐1) at the end of reperfusion.Conclusion: We conclude that at the concentration used in this study propofol shows no improvement in contractility during “stunning” when compared to fentanyl.