bluuebunny/crossref_metadata_2025 huggingface dataset:
Onset and duration of action of vecuronium in the elderly: comparison with adults
Authors: McCarthy G. , Elliott P. , Mirakhur R. K. , Cooper R. , Sharpe T. D. E. , Clarke R. S. J.
Published: January 2009

The onset and duration of action of vecuronium were studied in young adult (n = 30; mean age 34 ± 11.1 (s.d.) yr), middle‐aged (n = 20; mean age 60 ± 5.8 yr) and elderly patients (n = 30; mean age 80 ± 4.6 yr) anaesthetised with thiopentone, nitrous oxide in oxygen and halothane. Neuromuscular block was monitored by applying the train‐of‐four (TOF) stimulation at 2 Hz to the ulnar nerve every 12 s. Half the patients in each group received 0.08 and the other half 0.12 mg kg‐1 of the relaxant. The time to return of T1 (first response in the TOF sequence) to 25% of control was 28 ± 5.2 (s.d.), 34 ± 7.1 and 39 ± 10.2 min following 0.08 mg kg‐1 dose (P<0.05 between the elderly and young adults) and 45 ± 9.2, 48 ± 6.2 and 69 ± 19.2 min following 0.12 mg kg‐1 dose, respectively, in the three age groups (P<0.05 between the elderly and the other two groups). The recovery indices (time for 25–75% recovery of T1) after the 0.08 mg kg‐1 was 9.6 ± 3.4, 13.6 ± 5.1 and 17.4 ± 6.1 min, respectively (P<0.05 between the elderly and young adults). There was no significant difference in any of the parameters between the young adults and the middle‐aged. The onset of block at each dose was not significantly different between the three age groups; however, the time to maximum effect was significantly shorter with the higher dose in the young and the middle‐aged, but not in the elderly. Regression analysis of the data between age and the duration of action and recovery index suggested a significant prolongation (P<0.05) of these parameters in the elderly.
Evidence against endogenously released adenosine as modulator of the pressor response to hypoxia in isolated rat lungs
Authors: Jolin Å. , Kjæve J. , Helset E. , Tollåli T. , Sollevi A. , Bjertnæs L.
Published: January 2009

Unlike other vascular beds, lung vessels constrict when exposed to hypoxia. However, a marked difference has been noticed as regards the elicitability of hypoxic pulmonary vasoconstriction (HPV) in vivo as compared to in vitro models, like a preparation of isolated rat lungs; in the latter, HPV cannot be evoked from the onset of perfusion, but might be triggered gradually by repeated hypoxic challenges. The formation of adenosine, a potent dilator of most vascular beds, is enhanced during conditions of hypoxia or ischemia. Our hypothesis therefore was that pulmonary vasoconstriction was initially antagonized by tissue‐adenosine accumulating during the circulatory arrest necessary for lung isolation, and then, gradually invigorated along with the elimination of adenosine during periods of perfusion with normally oxygenated blood. In a first series of isolated rat lungs, we studied release of adenosine in connection with the third and the sixth hypoxic challenges. Although the vascular responses were of significantly different size, there was no sign of increased adenosine formation during any of the two provocations, as assessed by release of its more stable metabolites hypoxanthine, xanthine and uric acid. In a series of tissue preparations taken at the height of a fully developed hypoxic pressor response and immediately frozen, we could not find significant changes in tissue level of adenosine, hypoxanthine and inosine as compared to controls that had never been exposed to hypoxic challenges. Further, we found no correlation between the size of pressor responses and concentrations of adenosine and its metabolites, in either blood or in lung tissue. The results, in contrast to those of previous workers, indicate that adenosine formation is not favoured in hypoxic lungs.
Central cholinergic action produces antagonism to ketamine anesthesia
Authors: Mimura M. , Namiki A. , Kishi R. , Ikeda T. , Miyake H. , Iwasaki H.
Published: January 2009

Ketamine sometimes produces posthypnotic emergency reactions, such as prolonged hallucination or delirium. In a previous paper, we showed that physostigmine, an anticholinesterase agent, counteracts the manifestation of effects of ketamine at some doses. In the present study, we investigated the mechanism of the antagonistic effect of physostigmine on ketamine anesthesia. At first, rats were given ketamine 75 mg/kg. Immediately after the loss of righting reflex, the four groups of rats were given one of the three central cholinergic agents, physostigmine 0.1 mg/kg, oxotremorine 0.05 mg/kg, 4‐aminopyridine 3 mg/kg, or saline as the control. The sleeping times were 10.7 ± 1.0, 12.3 ± 0.9, 11.4 ± 1.3 and 21.2 ± 0.7 min, respectively. The three cholinergic agents antagonized ketamine anesthesia. In the other groups of rats, the central anticholinergic agent, l‐hyoscyamine, 0.5 mg/kg, was given subcutaneously for premedication before the above‐mentioned procedure. The sleeping times were 16.3 ± 1.2 min in the physostigmine group, 18.7 ± 1.0 min in the oxotremorine group and 18.6 ± 0.8 min in the 4‐aminopyridine group. The sleeping time was significantly longer in the premedicated group than in the non‐premedicated group, in the case of the three central cholinergic agents. The sleeping time in the saline group, 20.0 ± 0.4 min, was not significantly different from that of the control in the non‐premedicated case. It is, therefore, considered that the central cholinergic action produces antagonism to ketamine anesthesia.
Perioperative complement activation in neonates under halothane or fentanyl anaesthesia
Authors: Mikawa K. , Maekawa N. , Goto R. , Yaku H. , Obara H.
Published: January 2009

We investigated perioperative changes in complement activation in 18 neonates undergoing elective abdominal surgery with or without thoracotomy by measuring plasma concentrations of C3a and C5a, and leucocyte counts in peripheral blood. The 18 neonates, ranging in age from 1 to 17 days, were randomly divided into two groups according to type of anaesthetic procedures; the “halothane group” consisted of nine neonates in whom general anaesthesia was maintained with halothane and nitrous oxide (N2O) in oxygen, while the “fentanyl group” consisted of nine neonates in whom general anaesthesia was maintained with fentanyl and N2O in oxygen. Plasma C3a and C5a concentrations were higher in the fentanyl group than in the halothane group during the perioperative period. We have demonstrated that abdominal surgical trauma caused complement activation even in neonates undergoing the fentanyl rather than the halothane anaesthesia. Further studies are required to elucidate the precise mechanisms and the clinical implication of perioperative complement activation in neonates.
High frequency jet ventilation: use of the Bain system for entrainment
Authors: Buist R. J. , Lim M. , Francis D.
Published: January 2009

The use of a Bain system to convey anaesthetic gases for entrainment during high frequency jet ventilation (HFJV) was evaluated by examining the effect of varying the fresh gas flow (Vf) on the end‐tidal carbon dioxide (PE***, co2) in 46 ASA physical status I and II patients undergoing extracorporeal shock‐wave lithotripsy (ESWL). Anaesthesia was induced with methohexitone (1–2 mg ˙ kg‐1), fentanyl (1–1.5 μg ˙ kg‐1) and vecuronium (0.1 mg˙ kg‐1). After endotracheal intubation with a Mallinckrodt Hi‐Lo Jet cuffed endotracheal tube, the patient was immersed in a water bath and HFJV at 150 breaths per minute was instituted with an Acutronic AMS 1000 jet ventilator attached to the side channel of the Hi‐Lo tube. A Bain system was attached to the proximal end of the endotracheal tube to provide gases for entrainment. Anaesthesia was maintained with an intravenous infusion of methohexitone (5 mg ˙ kg‐1 ˙ h‐1) and 50% nitrous oxide in oxygen for both the jetted and entrained gases. PE, co2 was determined at 5‐min intervals by a single‐breath technique using a calibrated Engstrom Eliza capnograph. Thirty patients were randomly allocated to receive Vf's of 50 (Group 1), 75 (Group 2) and 100 (Group 3) ml ˙ kg‐1 ˙ min‐1, respectively. A further eight patients (Group 4) received a Vf of 100 ml ˙ kg‐1 ˙ min‐1 for 15 min, 75 ml ˙ kg‐1 ˙ min‐1 for the next 15 min and 50 ml ˙ kg‐1 ˙ min‐1 thereafter. In a further group of eight patients (Group 5), Vf was initially 25 ml ˙ kg‐1 ˙ min‐1 for 10 min and was then switched off for the remainder of the procedure. The results indicate that the magnitude of Vf supplied to a Bain system when this is used to provide gases for entrainment during HFJV has a negligible effect on carbon dioxide elimination.
Combined use of hypothermia and buffering in the treatment of critical respiratory failure
Authors: Wetterberg T. , Steen S.
Published: January 2009

A 20‐year‐old male, recovering from post‐traumatic ARDS, subsequently developed pneumonia with extreme hypercapnia (Paco2 max 19.4 kPa) and hypoxemia (Pao2 min 5.1 kPa), in spite of maximal mechanical ventilation. Hypothermia was induced by surface cooling, reducing the body temperature from 40°C to a mean of 33.3°C. Buffer infusion (1375 mmol) during the first 2 days increased base excess from 3 to 22 mmol/l and pH from 7.16 to a median value of 7.30. Active cooling was discontinued on day 11. Weaning from the ventilator was possible 9 days later and the patient subsequently recovered fully. Combined use of hypothermia and buffering might offer an alternative to extracorporeal lung assist (ECLA) and facilitate a reduction of barotrauma and oxygen toxicity during mechanical ventilation.
Influence of the type of anaesthesia on post‐operative subjective physical well‐being and mental function in elderly patients
Authors: Crul B. J. P. , Hulstijn W. , Burger I. C.
Published: January 2009

Standardized behavioural observations were used to establish the influence of the type of anaesthesia on the mental function and the subjective physical well‐being in 60 patients, all men, following urological surgery. The patients were randomized to two groups, receiving spinal or general anaesthesia. For evaluation of the influence of pre‐operative physical condition on post‐operative mental function, a supplementary group of 34 patients with pre‐existing cardiovascular and/or pulmonary disorders was included in the study. These patients all received spinal anaesthesia. The patients were observed from the day before surgery until 4 weeks after. In all patients a short‐lasting temporary decline in mental function was observed. The outcome was not influenced by the type of anaesthesia. In the two groups receiving spinal anaesthesia the decline in post‐operative mental function and subjective sense of well‐being was most pronounced in patients with a compromised physical condition pre‐operatively. Four weeks after surgery, no signs of mental deterioration were present; however, the subjective sense of physical well‐being had not fully returned.
Effects of acute isovolemic hemodilution and anesthesia on regional function in left ventricular myocardium with compromised coronary blood flow
Authors: Spahn D. R. , Smith L. R. , Mcrae R. L. , Leone B. J.
Published: January 2009

The effects of progressive, isovolemic hemodilution using Dextran 70 and the effect of halothane (0.7, 0.9, 1.1, and 1.3% end‐tidal, administered randomly at each level of hemodilution) on global cardiovascular and regional LV contractile functions were investigated in 24 dogs with induced critical constriction of the left anterior descending coronary artery (LAD). Two additional groups of six dogs each (with and without LAD stenosis) not undergoing hemodilution served as time controls. Regional LV contractile function was assessed by sonomicrometry in the flow‐compromised apical LAD territory, as well as in three non‐compromised LV areas supplied by the left circumflex coronary artery. Regional myocardial function was found to be stable throughout the study period of 4–5 h in both time control groups. Mean arterial and coronary perfusion pressures as well as LV dP/dtmin decreased (P<0.01) during hemodilution. LV dP/dtmax remained unchanged, and heart rate and LVEDP increased slightly (P<0.05). Systolic shortening (SS) in the LAD territory was unchanged at a hematocrit (HCT) of 33.5 ± 0.3% (mean ± s.e. mean), and decreased marginally at an HCT of 24.2 ± 0.1% (SS of 17.4 ± 1.0% as compared to 20.2 ± 1.6% at critical constriction (CC), P<0.05). No increase in post‐systolic shortening (PSS) occurred in the compromised area. Severe LAD dysfunction was observed in the LAD territory at an HCT of 14.9 ± 0.1%, as systolic shortening decreased (11.8 ± 1.1%, P<0.01 vs CC) and PSS increased (31.2 ± 3.4%, P<0.01 vs CC). The effects of hemodilution on global cardiovascular and regional myocardial functions were unaffected by halothane. Mild and moderate hemodilution therefore are relatively well tolerated in LV areas supplied by a compromised coronary artery, and the critical level of isovolemic hemodilution is between a hematocrit of 15 and 25% in dogs.
Effects of verapamil on histamine‐induced changes in lung mechanics
Authors: Mima M. , Taguchi H. , Oya M.
Published: January 2009

The effects of verapamil on airway resistance and total thoracic compliance were studied in 15 rabbits with histamine‐induced changes in lung mechanics. The animals, after being tracheotomized under anaesthesia, were subjected to mechanical ventilation in a time‐cycled, volume‐limited mode. Airway pressure and gas flow signals measured by a pneumotachograph and integrated for volume, were registered on a recorder. Each animal was given histamine hydrochloride in an isotonic solution of sodium chloride at a rate of 0.05 μg · kg‐1 · min‐1 through a peripheral venous line. Verapamil was infused intravenously in an isotonic solution of sodium chloride at a rate of 20 μg · kg‐1 · min‐1 after the initiation of histamine. Verapamil reduced the histamine‐induced increase in airway resistance by 20% at 20 min after the start of administration.
Effects of epinephrine and clonidine on plasma concentrations of spinal bupivacaine
Authors: Boico O. , Bonnet F. , Mazoit J. X.
Published: January 2009

ASA II–III patients, scheduled for peripheral vascular surgery, were included in a study designed to assess the effect of spinal epinephrine and clonidine on plasma concentrations of spinally administered 0.5% glucose‐free bupivacaine. Patients were allocated randomly to three groups to receive via a spinal catheter 22.5 mg (4.5 ml) of bupivacaine alone (Group B, 9 patients) or combined with 0.3 mg epinephrine (Group BE, 10 patients) or 0.15 mg clonidine (Group BC, 10 patients). Sensory blockade was assessed by pin‐prick and motor blockade on the Bromage scale. Bupivacaine plasma concentrations were measured by gas chromatography. A trend to prolongation of local anaesthetic blockade was documented in patients receiving bupivacaine plus epinephrine or clonidine. (Time to regression of sensory blockade to L2: 170 ± 75 min in Group B, 230 ± 50 min in Group BE, 232 ± 64 min in Group BC.) The maximum peak concentration (Cmax), the time to reach Cmax(Tmax) and the time‐concentration curve from 0–180 min (AUC) were not different for the three groups (Cmax228 ± 112 ng · ml‐1in Group B, 215 ± 103 ng · ml‐1in Group BE, 234 ± 159 ng · ml‐1in Group BC; Tmax41 ± 34 min in Group B, 59 ± 31 min in Group BE, 68 ± 32 min in Group BC; AUC 31.0 ± 1.7 mg · ml‐1· min‐1in Group B, 27.3 ± 1.1 mg · ml‐1· min‐1in Group BE, 27.0 ± 1.1 mg · ml‐1· min‐1in Group BC). The results of this study suggest that epinephrine and clonidine do not decrease blood resorption of spinal bupivacaine.
A two‐dose epidural morphine regimen for cesarean section patients: therapeutic efficacy
Authors: Zakowski M. I. , Ramanathan S. , Turndorf H.
Published: January 2009

A single dose of epidural morphine (EM) usually produces 24 h of post‐cesarean section (CS) analgesia and patients require supplemental analgesics beyond this period. This study assesses if a second dose of EM administered 24 h after the first one offers superior therapeutic efficacy compared to conventional analgesics. Patients (n = 100) were randomized to receive one or two doses of epidural morphine. In all patients, EM 5 mg was administered after delivery. After 24 h patients received epidurally either normal saline (n = 50, Group 1) or morphine 5 mg (n = 50, Group 2). An independent observer used a visual analogue scale to assess nausea, itching, and analgesia 24 h after each injection. Results were expressed as mean ± 1 s.e. mean and analyzed using nonparametric methods. The second dose of EM produced a significantly lower incidence and severity of nausea and itching than did the first dose (P<0.01) in Group 2 with no difference in analgesia. The second day postoperative pain score in Group 1 was significantly greater than the first day score in the same group, and significantly greater than the severity score in Group 2. Only 36% of patients receiving two doses of EM required supplemental analgesics beyond 48 h compared to 76% of those receiving one dose (P<0.01). No serious complications were noted. In summary, the use of a second dose of EM for post‐CS analgesia produces better analgesia and reduces the need for oral analgesics. The second dose produced fewer side‐effects, probably due to acute tolerance to morphine.
Failure of anaesthesia after accidental subdural catheter placement
Authors: van der Maaten J. M. A. A. , van Kleef J. W.
Published: January 2009

A case is described where an epidural anaesthetic was complicated by dural puncture, following which attempted conversion to a continuous subarachnoid infusion technique resulted in failure of anaesthesia. Accidental subdural catheter placement was confirmed radiologically, subdural spread of solution being demonstrated; however, only minimal anaesthetic effects were produced.
Atracurium‐induced neuromuscular block in the isolated arm
Authors: Eriksson L. I. , Vandenbrom R. H. G. , Lennmarken C. , Agoston S.
Published: January 2009

A modification of the isolated arm technique was applied in 10 females under opioid‐based i.v. anaesthesia for comparison of the offset of an atracurium‐induced neuromuscular block in an isolated arm to an arm with maintained circulation. The neuromuscular blocking effect of a bolus dose of atracurium 0.5 mg · kg‐1 was measured bilaterally using the integrated adductor pollicis EMG response (integrated T1 EMG response in % of baseline value and T4/T1 ratio) after bilateral ulnar nerve train‐of‐four (TOF) stimulation. At 10% T1 recovery, one arm was isolated from the general circulation for 20 min by means of a tourniquet cuff (isolated arm), while normal circulation was maintained in the other arm (control arm). In both arms, the TOF response, peripheral skin temperature, mixed peripheral venous pH and plasma concentrations of atracurium and laudanosine were then measured and compared. Core and peripheral skin temperatures in both arms remained stable and normal throughout the study, and mixed peripheral venous pH stayed within physiological limits in both arms in all subjects. In the isolated arm, recovery of the neuromuscular block was markedly delayed compared to the control arm, the integrated EMG T1 response and TOF ratio being significantly reduced in the isolated arm after 20 min of isolation. The decline in plasma concentration of atracurium was less in the isolated arm than in the control arm, whereas laudanosine levels increased in the isolated and decreased in the control arm. Normal peripheral circulation is of major importance for termination of an atracurium‐induced neuromuscular block. The contribution of Hofmann elimination to termination of an atracurium‐induced neuromuscular block appears to be of minor importance.
Sublingual premedication with brotizolam
Authors: Laub M. , Espersen K. , Ejlersen E. , Krintel J. J.
Published: January 2009

This randomized, double‐blind and double‐dummy study was carried out in order to compare the perioperative sedation after premedication with either brotizolam 0.25–0.50 mg sublingually or diazepam 5–10 mg orally. Sixty‐two patients aged 18–60 years scheduled for minor gynaecological surgery in general anaesthesia were included. Assessments were: 1. auditory continued response time (ACRT); 2. coma scale; 3. anxiety scale; and 4. final patient questionnaire. One hour after premedication the brotizolam group was more sedated, based on ACRT (P<0.01) and the coma scale (P<0.05). The final questionnaire showed (P<0.05) that the brotizolam group was more satisfied with the effect of the premedication. Seven hours after the premedication the ACRT scores in both groups were similar to those before premedication and all the patients could walk about freely. In conclusion, as a premedicant in outpatients sublingual brotizolam appears to be a good alternative to diazepam.
Lidocaine pretreatment effectively decreases the incidence of hiccups during methohexitone administration for dilatation and curettage
Authors: Weksler N. , Stav A. , Ovadia L. , Berman M. , Segal A. , Ribac L. , Lemberg L.
Published: January 2009

The efficacy of lidocaine 1 mg · kg‐1 for prevention of methohexitone‐induced hiccups was assessed in a double‐blind fashion in 200 patients undergoing dilatation and curettage for pregnancy interruption. The patients were randomly assigned to receive either lidocaine 1% or saline 0.9% in a similar way (1 ml for every 10 kg of body weight). The incidence of hiccups was 16% in the control group compared to 6% in the lidocaine group. We speculate that this reduction in the methohexitone‐induced hiccup ratio is related to lidocaine's membrane‐stabilizing properties, which decrease the excitability of all the nervous structures involved in this reflex.
The effects of propofol, methohexitone and isoflurane on the baroreceptor reflex in the cat
Authors: Sellgren J. , Biber B. , Henriksson B. Å. , Martner J. , Pontén J.
Published: January 2009

The effects of propofol (P), methohexitone (M) and isoflurane (I) on the baroreceptor reflex were studied in a cat model in which the blood pressure in a bilateral isolated carotid sinus preparation was artificially varied between 50–200 mmHg. The influence from aortic and cardiopulmonary baroreceptors was excluded by vagotomy. With basal chloralose anaesthesia as control, the investigated anaesthetics were used in doses corresponding to MAC 0.5 and 1.0. The maximum change in systemic mean arterial pressure (MAP) and heart rate (HR) following a defined increase in carotid sinus pressure was used as an index of baroreceptor reflex sensitivity. Compared to control, M and I anaesthesia were associated with significant depression of baroreceptor reflex sensitivity at the high dose (corresponding to MAC 1.0), and during I anaesthesia also at the low dose (MAC 0.5). The baroreceptor reflex sensitivity was maintained during propofol anaesthesia. The carotid sinus pressure interval at which the maximum changes in MAP could be elicited, was significantly higher during M than during P. This indicates resetting of the baroreflex.
Elimination of apparatus dead space — a simple method for improving CO2 removal without increasing airway pressure
Authors: Larsson A.
Published: January 2009

During mechanical ventilation the apparatus dead space can be eliminated by insufflating through one lumen of a tracheal double‐lumen tube and allowing expiration through the other. In six intravenously anesthetized pigs, this technique resulted in an 18% (1 kPa) decrease in Paco2 compared with insufflating through both lumens (32 ml rebreathing volume). Oxygenation, airway pressures, and tidal volumes were unchanged. Flushing the trachea with fresh gas during the expiratory phase did not improve the efficiency of ventilation. It is concluded that elimination of apparatus dead space improves CO2 removal without increasing airway pressures and tidal volumes, and it is suggested that minimization of apparatus dead space should be tried before more advanced ventilatory modes are considered.
Gas exchange impairment and pulmonary densities after cardiac surgery
Authors: Hachenberg T. , Brüssel T. , Roos N. , Lenzen H. , Möllhoff T. , Gockel B. , Konertz W. , Wendt M.
Published: January 2009

In 11 patients with impaired respiratory function after coronary artery revascularization surgery, thoracic computed tomography (TCT) and cardiopulmonary profile were obtained. The patients were haemodynamically stable without clinical or radiological signs of lung oedema. Oxygenation was reduced in all patients (alveolo‐arterial Po2‐difference (PA‐aO2) = 37.3 ± 10.39 kPa, venous admixture (QVA/Qx) = 26.4 ± 4.4%) during mechanical ventilation with positive end‐expiratory pressure (PEEP = 5 cmH2O) (0.5 kPa). TCT‐scan analysis revealed considerable amounts of crest‐shaped bilateral densities in dependent lung regions. There were no differences between the right and left hemithorax. Atelectatic lung tissues were defined as areas presenting with attenuation values of ‐ 200 to + 20 Hounsfield Units. The magnitude of non‐ventilated areas correlated with QVA/QT (r = 0.875, P≤0.01), but not with the duration of either extracorporeal circulation, surgical procedure or general anaesthesia. It is concluded that atelectasis in dependent lung areas contributes to impaired gas exchange after cardiac surgery.
Hemodynamic interactions when combining verapamil, acute changes in extracellular ionized calcium concentration and enflurane, halothane or isoflurane in chronically instrumented dogs
Authors: Hysing E. S. , Chelly J. E. , Jacobson L. , Doursout M. F. , Merin R. G.
Published: January 2009

To assess the hemodynamic interactions when combining verapamil, acute changes in extracellular ionized calcium concentration [Ca2+] and enflurane (2.5%), halothane (1.2%) or isoflurane (1.6%), seven dogs were chronically instrumented to measure heart rate (HR), aortic, left atrial and left ventricular (LV) pressures, and cardiac output (CO). [Ca2+] was lowered 0.35 mmol · 1‐1 by citrate infusion and then increased 0.35 mmol·1‐1 above control level by CaCl2 infusions. Verapamil was infused at 3 μg·kg‐1 min‐1 (loading dose 200 (awake), 150 (isoflurane) or 100 (enflurane and halothane) μg · kg‐1), giving mean verapamil concentrations around 75 (range of means: 66–84 ng · ml‐1). Verapamil produced mostly minor changes in the cardiovascular effects of changing [Ca2+] in both awake and anesthetized dogs, indicating mostly additive effects. Verapamil induced a decrease in HR at high [Ca2+] and abolished an increase in mean aortic pressure at both low and high [Ca2+] awake. Verapamil exaggerated the decrease in CO and stroke volume (SV) induced by low [Ca2+] during enflurane anesthesia and abolished the increase in CO induced by low [Ca2+] and exaggerated the increase in SV and LV dP/dtmax induced by high [Ca2+] during halothane anesthesia.
Reduced left ventricular diameters at onset of bradycardia during epidural anaesthesia
Authors: Jacobsen J. , Søfelt S. , Brocks V. , Fernandes A. , Warberg J. , Secher N. H.
Published: January 2009

Pathophysiologic mechanisms of bradycardia during epidural anaesthesia (L3‐L4 with 1% lidocaine, 38 ml) were evaluated by studying changes in selected cardiovascular and hormonal parameters. Six of eight subjects (analgesia to T8‐T10) remained circulatory stable with no significant changes in heart rate (HR), mean arterial pressure (MAP) and thoracic impedance (TI). In one of two subjects MAP decreased after 25 min from 85 to 50 mmHg (11.3 to 6.7 kPa), HR from 80 to 45 beats · min‐1 while thoracic impedance increased from 25.5 to 26.5 ohm. End‐systolic diameter (ESD) and end‐diastolic diameter (EDD) of the left ventricle determined with echocardiography were reduced from 3.8 to 3.2 cm (17%) and 5.6 to 5.0 cm (11%), respectively. In the other subject MAP decreased after 25 min from 75 to 50 mmHg (10.0 to 6.7 kPa) and HR from 82 to 60 beats · min‐1 while thoracic impedance increased from 28.8 to 29.6 ohm. ESD was reduced from 3.8 to 3.3 cm (13%), and EDD from 5.6 to 5.0 cm (11%). Both subjects recovered after infusion of saline and being placed in the head‐down position. There were no consistent changes in plasma catecholamines, whereas pancreatic polypeptide increased from 5 and 3 to 152 and 69 pmol·1‐1, vasopressin from 3 and 2 to 152 and 46 pmol·1‐1, and aldosterone from 282 and 229 to 383 and 485 pmol·‐1, respectively. The established level of analgesia suggests that the changes in circulatory and hormonal variables as well as successful resuscitation of the subjects with saline in the head‐down position conform to central blood volume depletion leading to increased vagal tone. During epidural anaesthesia presyncopal symptoms were preceded by an approximately 13% reduction in left ventricular diameters.
Direct spinal effect of intrathecal acetaminophen on visceral noxious stimulation in rabbits
Authors: Jensen F. Molke , Dahl J. B. , Frigast C.
Published: January 2009

The aim of this study was to investigate the effect of intrathecal acetaminophen on visceral and somatic noxious stimulation in the intact, non‐anesthetized rabbit. Sixteen rabbits had intrathecal catheters implanted surgically. Visceral noxious stimulation was induced by intestinal distension of the distal colon and somatic stimulation with increasing electrical current through skin electrodes placed in either the cervical or the lumbar area. The effect on visceral noxious stimulation was assessed following intrathecal injection of 0.5, 2.5 and 5 mg of acetaminophen and following 10 and 50 mg acetaminophen intravenously. Naloxone 0.2 mg and yohimbine 0.1 mg were administered intrathecally prior to intrathecal injection of acetaminophen 5 mg. A dose‐dependent effect of intrathecal acetaminophen against the visceromotor reflex produced by intestinal distension was shown. No effects on thresholds to lumbar or cervical electrical stimulation or intestinal distension were observed following i.v. administration. Thresholds to noxious electrical stimulation were only significantly elevated at the lumbar level following i.t. injection of 5 mg acetaminophen. Naloxone failed to antagonize the effect of intrathecal acetaminophen, whereas intrathecal yohimbine attenuated the effect of intrathecal acetaminophen in both tests. In conclusion, a spinal, dose‐dependent, naloxone‐irreversible, and yohimbine‐reversible effect of intrathecal acetaminophen on electrical and visceral noxious stimulation was demonstrated.
Endogenous and exogenous nitrates
Authors: ÄNggård E. E.
Published: January 2009

The endothelium‐derived relaxing factor (EDRF) is nitric oxide (NO) or a closely related nitrosothiol derivative. It is formed from the amino acid, L‐arginine. NO is rapidly inactivated locally and is instantly destroyed by haemoglobin when released into the blood stream. EDRF‐NO as well as NO generated from vasodilator nitrates act by activation of soluble guanylate cyclase, elevating cellular cyclic GMP levels, causing vasodilatation and inhibition of platelet aggregation. Endothelium‐dependent vasodilatation is attenuated in hypertension, atherosclerosis and diabetes. This is due to either loss of endothelium or deficient formation of EDRF‐NO. In these conditions, therapy with exogenous nitrates may substitute for a failing endogenous mechanism.
Renal effects of high dose desmopressin and dextran. A study in normal subjects and in patients undergoing total hip replacement
Authors: Flordal P. A. , LjungstrÖoUm K.‐G.
Published: January 2009

Dextran 70 and the haemostatically active vasopressin analogue desmopressin were administered to four healthy volunteers and to 12 patients undergoing total hip replacement. In volunteers the antidiuretic effect of a single i.v. dose of desmopressin (0.3 μg/kg bodyweight) caused a mean net urine deficit, compared with controls, of 890 ml/24 h. Both drugs increased estimated blood volume, but only the combination caused an increase still persisting after 24 h (+ 530 ml). Desmopressin‐treated surgical patients had the same urine volumes as controls, without the use of more diuretics or more i.v. fluid administration. Creatinine clearance was significantly increased postoperatively in patients on desmopressin, compared with controls. Thus the long‐lasting antidiuretic effect of desmopressin seen in healthy volunteers was absent in surgical patients, possibly because there was a compensatory increase in glomerular filtration rate (creatinine clearance).
The effects of prophylactic dixyrazine on postoperative vomiting after two different anaesthetic methods for squint surgery in children
Authors: Karlsson E. , Larsson L. E. , Nilsson K.
Published: January 2009

The incidence of postoperative vomiting after squint surgery was studied for two anaesthetic techniques with and without prophylactic dixyrazine. After induction, anaesthesia was maintained with either fentanyl/pancuronium/nitrous oxide or halothane/nitrous oxide in two randomly selected groups of 58 children each. Half of the children in each group were randomly allocated to receive dixyrazine 0.25 mg kg‐1 i.v. after surgery had been completed but before reversal of muscle relaxants or termination of anaesthesia. With prophylactic dixyrazine the incidence of postoperative vomiting was significantly reduced from 69% (20/29) to 21% (6/29) in the fentanyl group and from 45% (13/29) to 10% (3/29) in the halothane group. Without prophylactic dixyrazine, 20 of 29 children in the fentanyl group vomited compared to 13 of 29 in the halothane group (n.s.). Thus, prophylactic dixyrazine reduced the incidence of vomiting in children given either opioid or halothane anaesthesia for squint surgery. In comparable groups avoidance of opioid anaesthetic technique and use of prophylactic dixyrazine resulted in a greatly reduced incidence of vomiting.
Duration of experimental nerve block by combinations of local anesthetic agents
Authors: Hassan H. G. , Youssef H. , Renck H.
Published: January 2009

The effects of bupivacaine‐prilocaine and meperidine‐lidocaine combinations (as compared with those of the agents used alone) on the duration of peripheral sensory nerve block were studied with the infraorbital nerve block model (IONB) in the rat, and those on motor block with spinal anesthesia (SA) in the mouse. The duration of bupivacaine‐induced IONB was invariably prolonged when prilocaine was included in the solution. When included in 0.125% bupivacaine, 1.0% prilocaine had a slightly less pronounced enhancing efTect than 0.5% prilocaine (24–57% vs. 74%‐104%, respectively). The duration of IONB with 1.0% prilocaine was significantly reduced (14–37%) by inclusion of 0.125% bupivacaine. In SA, inclusion in 0.125% bupivacaine of prilocaine (0.5% or 1.0%) prolonged motor block by 128% and 192%, respectively. When included in 0.25% bupivacaine, both 0.5% and 1.0% prilocaine significantly reduced the duration of SA, by 42% and 37%, respectively. With one exception, the duration of IONB by meperidine was significantly shortened (<44%) when lidocaine was included in the solution. In SA, inclusion of 2% lidocaine with 2% meperidine did not affect the duration of meperidine‐induced motor block. The duration of SA obtained with the combination of 4% lidocaine and 4% meperidine was 45% shorter than that induced by 4% meperidine alone. The reasons for these variable effects are not clear, but may be due to interaction or antagonism at any of multiple sites.
Coronary artery spasm with ventricular tachycardia after administration of methoxamine during cervical epidural anesthesia ‐ a case report
Authors: Mizuyama K. , Dohi S. , Harukuni I.
Published: January 2009

Coronary artery spasm occurred during thoracotomy under cervical epidural anesthesia in a 60‐year‐old male patient who had no prior history of myocardial ischemia. It is most likely that the administration of methoxamine induced the spasm. Hypotension and venodilatation induced by the epidural anesthesia and increased vagal tone might also contribute to the spasm.
Cerebral haemodynamic and electrocortical CO2 reactivity in pigs anaesthetized with fentanyl, nitrous oxide and pancuronium
Authors: ÅAkeson J. , Messeter K. , Rosen I. , BjÖoUrkman S.
Published: January 2009

Cerebral haemodynamic, metabolic and electrocortical reactivity to alterations in arterial CO2, tension (PaCO2) was assessed in seven mechanically ventilated juvenile pigs to test an experimental model designed for cerebral pharmacodynamic and pharmacokinetic studies. The animals were anaesthetized with fentanyl, nitrous oxide and pancuronium and sequentially normo‐ and hyperventilated over a 100‐min period. Five measurements were made at 25‐min intervals. The cerebral blood flow (CBF) was measured with the intraarterial 133Xe technique and the cerebral metabolic rate for oxygen (CMRo2) determined from CBF and the cerebral arteriovenous oxygen content difference. A linear correlation (r = 0.845) was found between CBF and PaCO2. The cerebrovascular reactivity to hypocapnia (ΔCBF/ΔPaCO2) was maintained throughout the experimental period and amounted to (95% confidence interval) 9.1 (7.1–11.1) ml · 100 g‐1 · min‐1 · kPa‐1 within the PaCO2 range 3.3–6.3 kPa. The CMRo2 was not influenced by hyperventilation. The baseline electroencephalographic (EEG) pattern was stable at normocapnia (mean PaCO2 5.6 kPa), whereas spectral values for delta and total average voltage increased significantly (P<0.05) at extensive hypocapnia (3.5 kPa). Maintenance of cerebral CO2 reactivity and spectral EEG voltage at a stable plasma level of fentanyl is complementary to the cerebral haemodynamic and metabolic stability previously found at sustained normocapnia in this model.
Enhanced pneumonia resolution by inhalation of nitric oxide?
Authors: Blomqvist H. , Wickerts C. J. , Andreen M. , Ullberg U. , ÖOUrtqvist ÅAR. , Frostell C.
Published: January 2009

We present a patient with severe bacteraemic pneumococcal pneumonia associated with severe hypoxaemia, where nitric oxide (NO) 15–40 ppm was added to the inspired gas. Nitric oxide therapy improved gas exchange, reduced pulmonary vasoconstriction and peak airway pressure. The patient survived. We observed an unexpected rapid and complete disappearance of bilateral pulmonary infiltrates during the first 120 h of the 7‐day NO inhalation period.
Prolonged total extracorporeal lung assistance without systemic heparinization
Authors: Fjalldal O. , Torfason B. , ÖNundarson P. T. , Thorsteinsson A. , VigfúuAsson G. , StefÁaAnsson T. , MagnÚuAsson V.
Published: January 2009

A 16‐year‐old female developed severe ARDS in her single remaining lung following pneumonectomy for blunt trauma. Total extracorporeal lung assist (ECLA) for 40 days using a covalently heparin‐coated circuit proved lifesaving. Systemic heparinization was not applied, as the heparinized surface by itself prevented clotting of the extracorporeal circuit. Systemic primary fibrinolysis developed but was not associated with major bleeding. A veno‐right ventricular cannulation technique was used and maximum venous drainage for the extracorporeal circulation was achieved by elevating the bed 50 cm from the floor. This allowed extracorporeal blood flow (ECBF) approaching cardiac output (CO) and complete extracorporeal replacement of lung function. After 40 days, lung recovery allowed discontinuation of ECLA. Five days later the patient suffered serious lung collapse and was operated for a bronchopleural fistula. The patient was extubated 4 weeks after terminating ECLA and discharged in good condition 5 weeks later.
Slow potentials of EEG burst suppression pattern during anaesthesia
Authors: JÄaUntti V. , Yli‐Hankala A. , Baer G. A. , Porkkala T.
Published: January 2009

EEG burst suppression pattern was recorded during propofol and isoflurane anaesthesia. Using a long time constant, i.e. a high‐pass filter with low cut‐off frequency, revealed slow potentials, DC shifts, during bursts. These have been extensively studied in conjunction with cognitive‐evoked potentials and epileptic discharges, but not previously in burst suppression EEG.
Hepatic disposition of sufentanil in patients undergoing coronary bypass surgery
Authors: Lange H. , Stephan H. , Zielmann S. , Sonntag H.
Published: January 2009

In order to clarify the relative contribution of the liver to the short‐term disposition of sufentanil, hepatic blood flow was measured during induction of anaesthesia with a 10 μg/kg i.v. bolus dose of sufentanil followed by a continuous infusion of 0.3 μg/kg/min of sufentanil. The hepatic clearance of the drug was 0.57 1/min after induction and 0.55 1/min at sternotomy, its hepatic extraction 92% and 91%, respectively. As a consequence of the high hepatic extraction, the hepatic clearance of sufentanil was closely dependent on hepatic plasma flow. Comparing the hepatic clearance of sufentanil with data from the literature for total body clearance of sufentanil, there is a significant difference of more than 0.3 1/min. It is concluded that there is evidence for a relevant extrahepatic disposition of sufentanil.
Variability of pipecuronium neuromuscular blockade
Authors: Diefenbach C. , Mellinghoff H. , Buzello W.
Published: January 2009

The dose‐response relationship and the variability of the time variables in pipecuronium neuromuscular blockade were studied in 29 patients (ASA physical status 3) during halothane anaesthesia. The ED95 (twitch tension) was determined in 9 patients using the cumulative dose response technique. Another 20 patients received the resulting ED95 as a single bolus. The mean ED95 was 35 μg‐kg‐1 (95% confidence interval: 29–41 μg.kg‐1). Following bolus injection of 1. ED95, an 80–100% twitch depression was achieved within 4.6±1.3 min (mean ± s.d.). The duration from end of injection of pipecuronium to 25% twitch recovery, the time from 25% to 75% twitch recovery, and the time from 25% twitch recovery to the train‐of‐four ratio (TOF) returning to 0.7 was 35 ± 14, 37 ± 26, and 63 ± 27 min, respectively. The time from end of injection to TOF = 0.7 varied within a 2‐h range (54–160 min). Thus, the time variables in pipecuronium neuromuscular blockade were as poorly predictable as those reported in the literature on pancuronium, alcuronium and doxacurium.
The onset of alcuronium and tubocurarine: alone and in combination
Authors: Roberts S. P. , Pollard B. J.
Published: January 2009

The rates of onset of neuromuscular blockade have been measured following 0.25 mg.kg‐1alcuronium (ED95), 0.51 mg.kg‐1tubocurarine (ED95), a combination of 50% of the ED95 of each and a combination of 33% of the ED95 of each. Train‐of‐four stimulation of the ulnar nerve was used with recording of the amplitude of the evoked compound electromyogram from the thenar prominence. The rate of increase in blockade in patients receiving the 50% combination was significantly greater than for either agent given alone, or than for the 33% combination. The mean time to 75% block of the first contraction of the train (T1) with the 50% mixture was 90 s, significantly faster than alcuronium alone (132 s), tubocurarine alone (174 s) or the 33% mixture (127 s). These latter three groups did not differ significantly. In conclusion, the rate of onset of the 50% combination resulted in a more rapid onset of neuromuscular blockade, whereas the rate of onset of the 33% combination was no different to that of either drug alone. This small degree of acceleration with agents which are known to be markedly synergistic makes it unlikely that this technique will prove to be of clinical importance.
Oesophageal thermal tube for intraoperative hypothermia in liver transplantation
Authors: Steib A. , Beller J. P. , von Bandel M. , Beck F. , Chabrol J. L. , Otteni J. C.
Published: January 2009

In order to prevent the occurrence of major hypothermia during liver transplantation, with its deleterious effects on intraoperative cardiovascular activity and on postoperative graft functioning, this study evaluated the benefit of an oesophageal rewarmer, used during surgery, in addition to the usual methods of warming (OR temperature at 22°C, rewarming of fluids and blood, heating mattress, heat and moisture exchanger). We compared 10 patients with an oesophageal rewarmer (OeR group) to 10 patients without (Control group). The anaesthetic procedure was similar in all cases. Rectal (RT) and pulmonary artery (PT) temperatures were recorded during the three phases of surgery (pre‐anhepatic, anhepatic, postanhepatic phase) and their time course was analysed with non‐parametric tests. The two groups were comparable with regard to duration of surgery, blood and fluid requirements and veno‐venous bypass flow rate. The RT decreased similarly in both groups, but was significantly higher in the OeR group at peritoneum closure (P<0.01). The PT was higher in the OeR group after onset of venous shunting (P<0.05) and during the third phase of surgery (P<0.01). Three incidents (one leakage and two herniations of the latex tube) occurred, without detrimental effects on the patients. It is concluded that the oesophageal heat exchanger allows better rewarming after revascularization of the graft, but is unable to prevent cardiac hypothermia at unclamping.
The effects of amrinone and calcium chloride on pulmonary vasculature and biventricular function in ethchlorvynol‐induced lung injury in sheep
Authors: Nakatsuka M. , Gehr L. C. , Glauser F. L.
Published: January 2009

The effects of amrinone and CaCl2on pulmonary vasculature and biventricular function in sheep with acute lung injury (ALI) were studied. Seven sheep were ventilated with a tidal volume of 10–12 ml.kg‐1with end‐tidal C02of 40 ± 5 mmHg (5.3 ± 0.7 kPa) after acute lung injury was induced with up to 30 mg kg‐1of ethchlorvynol (ECV). Biventricular function and hemodynamic profiles were estimated with a rapid computerized thermodilution method and modified pulmonary artery catheters after acute lung injury, following a loading dose (1 mg kg‐1) and maintenance dose (5 μg kg‐1min‐1) of amrinone and after a bolus dose of CaCl2(20 mg kg‐1). ECV successfully induced acute lung damage in sheep, causing significant increases in pulmonary artery pressure (PAP) and pulmonary vascular resistance index (PVRI). Amrinone reversed the unfavorable changes induced by ECV, significantly reducing PAP, PVRI and left ventricular end‐diastolic volume (LVEDV). CaCl2, however, reversed the effect of amrinone and increased PAP, PVRI, and LVEDV but decreased left ventricular ejection fraction.
Pregnancy outcome in an extremely small woman with muscular dystrophy and respiratory insufficiency
Authors: Ekblad U. , Kanto J.
Published: January 2009

Throughout her pregnancy and delivery, we followed a tiny 32‐year‐old woman suffering from muscular dystrophy and respiratory insufficiency. With carefully monitored maternal and fetal oxygenation and planned cesarean section under combined epidural and general anesthesia, she delivered a healthy baby at 32 gestational weeks.
Diaphragmatic activity during isoflurane anaesthesia in dogs
Authors: Ide T. , Kochi T. , Isono S. , Mizuguchi T.
Published: January 2009

The effect of isoflurane administration on diaphragmatic activity was investigated in six anaesthetized mechanically ventilated dogs. Diaphragmatic strength was assessed by measuring the transdiaphragmatic pressure (Pdi) generated during supramaximal stimulation of both cervical phrenic nerves at frequencies of 0.5, 10, 20, 50 and 100 Hz under partially isometric conditions at 1, 1.5 and 2 minimum alveolar anaesthetic concentrations (MAC), after maintaining 1 h of stable conditions. Pdi measurements were made at the start of the stimulation (initial) and at the end of a 2‐s period (2‐s). The force‐frequency relationship was compared at each anaesthetic level. For single twitch (0.5 Hz) stimulation, the time constant of diaphragmatic relaxation was also assessed. The sequence of changing anaesthetic depth was altered in random fashion between animals. Pdi amplitude at single twitch stimulation was unchanged at the three anaesthetic concentrations. There was no significant difference in initial Pdi at various stimulus frequencies with increasing depth of isoflurane anaesthesia. In addition, no change in 2‐s Pdi during low frequency stimulation (10 and 20 Hz) was noted during any of the three levels of anaesthesia. By contrast, 2‐s Pdi with 50 Hz stimulation during 2 MAC isoflurane exposure decreased significantly below Pdi levels seen at 1 and 1.5 MAC (P<O.O1). Furthermore, 2‐s Pdi at 100 Hz stimulation decreased significantly in a dose‐dependent fashion. From these results, we conclude that isoflurane reduces diaphragmatic activity at higher stimulation frequencies of 50 and 100 Hz.