摘要:

To see if the known properties of thiopental of reducing Ca2+and K+ fluxes across the myocardial sarcolemma account for its arrhythmogenic action, we have evaluated the effect of the anesthetic on spontaneous contractile activity induced in isolated rabbit papillary muscles. Thiopental (20 mg/1) prolonged the duration of sustained automaticity induced by stimulation at 1–2 Hz in the presence of 1 μmol/I isoproterenol. Thiopental (10, 20 mg/l) shortened the delay before the onset of Ba2+‐induced automaticity, which involves a decrease in a K+ current. The minimum concentration of Ba2+required to induce automaticity was lowered by thiopental. Whether spontaneous activities were induced by high frequency stimulation in the presence of isoproterenol or by Ba2+, thiopental lowered the frequency of spontaneous beats. Thus, thiopental appears to have both arrhythmogenic and antiarrhythmic actions, and the former may be unmasked when catecholamines counteract the latter by increasing Ca2+influx. Like thiopental, halothane (1.0%) decreased the frequency and force of Ba2+‐induced automatic beats but, unlike thiopental,prolongedthe delay before the onset of Ba2+‐induced automaticity, indicating that halothane acts as a purely antiarrhythmic agent in this type of auto

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb03313.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

There is thought to be a genetic defect within the calcium release channel of the sarcoplasmic reticulum in malignant hyperthermia (MH). This primary alteration is hypothesized to influence the function and/or structure of various muscle membrane systems; e.g., to have a direct effect on the composition of the lipid matrix. Therefore, in striated muscle samples, we determined the quantity and fatty acid composition of the various types of membrane phospholipids. German Landrace pigs were classified as normal or susceptible to MH. Total lipid content from longissimus dorsi, semi‐membranosus muscle, and heart left ventricular (HLV) samples were extracted with chloroform/methanol and subsequently separated by high performance liquid chromatograpy. The single phospholipid fractions were collected and, following derivatization, the quantities of individual fatty acids were determined using a capillary gas chromatographic method. In general, samples from the susceptible pigs contained lower absolute amounts of individual phospholipids. The most notable differences occurred in the HLV, where phosphatidylinositol, phosphatidylserine, phosphati‐dylethanolamine and sphingomyelin were all significantly less (P≤0.05). The muscle from the susceptible animals also contained decreased amounts of the polyunsaturated phospholipid‐bound fatty acids (P≤0.05). These differences in phospholipid and fatty acid concentrations of membranes isolated from swine susceptible to MH may relate to their apparently increased sensitivities to halothane (e.g., fluidizing effects) or elevated te

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb03314.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Seven healthy patients were investigated during midazolam‐fentanyl nitrous oxide‐oxygen anaesthesia. The mechanical twitch response of the adductor pollicis muscle was recorded simultaneously during bilateral supramaximal train‐of‐four (TOF) stimulation of the ulnar nerves at the wrist. Intense neuromuscular block was evaluated using the post‐tetanic count (PTC) method. Core temperature and the peripheral skin temperature of one arm were kept normal and stable. Following cooling of the other arm to a peripheral hand skin temperature of 27d̀C, vecuronium was administered in a bolus dose of 0.05 mg‐kg‐1followed by maintenance doses of 0.02 mg‐kg‐1. In the hypothermic and the normothermic arm the onset time following the bolus dose was 180 ± 40 (mean ± s.d.) seconds and 140 ± 30 s, respectively, the duration of action was 26.4 ± 4.5 and 16.5 ± 4.0 min and the recovery time was 265 ± 90 and 130±60 s (P<0.01). The time course of action following maintenance doses showed a similar marked difference between the hypothermic and the normothermic arm. In the normothermic arm a close correlation was found between the number of posttetanic twitches and the time to first response to TOF stimulation. In contrast, in the hypothermic arm the number of post‐tetanic twitches showed great variation with a poor correlation to the duration of intense neuromuscular block. It is concluded that the time course of action of a vecuronium‐induced neuromuscular block is markedly prolonged during peripheral hypothermia and intense neuromuscular block cannot reliably be assessed using the PTC method at low peripheral temperature. Normal coreandperipheral temperature is essential for correct evalua

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb03315.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

If ethanol is added to the irrigant used during transurethral prostatic resection, the absorption of fluid can immediately be detected by measuring the ethanol concentration in the expired breath. To evaluate this method further, we studied the influence of chronic obstructive pulmonary disease (COPD) on the agreement between expired‐breath and blood‐ethanol concentrations. In 14 men with a mean age of 62 years (range 55–68), the concentrations of ethanol in whole blood and end‐expired breath were measured at 12 exactly timed intervals before, during, and after an intravenous infusion of 0.6 g‐kg‐1ethanol for 60 min. The pulmonary function was normal in seven of the subjects (control group) whereas the other seven suffered from severe COPD (study group). The results show that the accuracy and precision of breath‐alcohol analysis to predict the blood‐ethanol level were poorer during the infusion of ethanol than afterwards. However, at all times of sampling the estimation of blood‐ethanol concentration indirectly by analysis of breath was not significantly different for COPD patients and the control group. We conclude that ethanol monitoring of irrigant absorption can be used successfully in p

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb03316.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The effects of a split‐dose of atropine sulphate versus a single dose of glycopyrrolate given with neostigmine for the reversal of gallamine‐induced neuromuscular blockade were studied in 55 patients undergoing gynaecological surgery. The patients were randomized to receive either a single dose of glycopyrrolate (7 μg ‐ kg‐1) or two doses of atropine (8 μg ‐ kg‐1each), given with an interval of 1 min. There were no differences between the two methods with respect to percentage heart rate changes, salivation or arousal time. Four patients demonstrated cardiac arhythmias in the atropine group, whereas none occurred in the glycopyrrolate group (P<0.05). It is concluded that a split‐dose of atropine has similar chronotropic effects to a single dose of glycopyrrolate for the reversal of gallamine‐induced neuromuscular blockade. However, the finding of a higher incidence of cardiac arrhythmias in the atropine group suggests that this reversal regime should be reserved for patients withou

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb03317.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The onset phase of hypoalgesia, following intrathecal morphine, was assessed by experimental argon laser‐induced pain. A dose of 0.4 mg morphine was injected pre‐operatively at the L3‐L4 level into nine patients. The thresholds to laser‐induced pain and pain‐evoked brain potentials were monitored for 2 h at the Sl, LI, and C7 dermatomes. Hypoalgesia was detected at the SI and LI dermatomes after 5 and 15 min, respectively. No hypoalgesic effect was found at C7. This indicates that hypoalgesia was caused predominantly by segmental spinal mechanisms during the onset phase, and not by a general widespread effect. No latency changes (conduction delay) of the brain potentials evoked from the hypoalgesic dermatomes were found. Cutaneous pain, induced experimentally by laser stimulation, has the advantage of being quantitative and is useful to assess the onset and the segmental spread of hy

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb03318.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Eighty patients undergoing a standardized balanced anaesthesia were randomly assigned to either a suggestion group (N = 38) or a control group (N = 42), in a double‐blind design. Anaesthesia was maintained with nitrous oxide, enflurane and fentanyl. Patients in the suggestion group were played seaside sounds, interrupted by statements of the importance of touching the ear during a postoperative visit, by means of a prerecorded audiotape and headphones. Tapes containing these suggestions were played from 30 min after the first incision, for a duration of 15 min. Patients in the control group were only played seaside sounds. There were no significant differences between the groups in either the number of patients touching their ears postoperatively or the number and duration of ear touche

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb03319.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Renal cortical microcirculation and its relation to inulin clearance, central haemodynamics and pulmonary gas exchange were studied in eight pigs under continuous intravenous chlormethiazole‐pancuronium anaesthesia. The animals were studied during six consecutive 30‐min periods. Four of the animals were also studied 19 h after the first period. In the superficial renal cortex, regional blood flow (Q) was measured by laser Doppler flowmetry (LDF) and tissue oxygenation (P1o2) by surface microelectrode technique. Central haemodynamics and pulmonary gas exchange values were distributed within normal ranges. The importance of stable central haemodynamics in order to perform accurate microcirculatory measurements in the renal cortex was documented. A significant relation between Q and pulmonary capillary wedge pressure (PCWP) was found (P<0.0001) despite the fact that PCWP was distributed within a range of only 0.7 kPa (all values were well within the normal range for pigs). No other relationships were found between central haemodynamics or pulmonary gas exchange variables and renal microcirculatory parameters. Concerning renal microcirculation and inulin clearance, at least 2–3 h may be required for stabilization after surgery. The average temporal variability between measurements performed every 30 min in each animal was 6 ± 7% (s.d.) in the LDF values and 21 ± 21% in the P1o2, values (mean P1o2,). No correlations were found between Q or P1o2, and inulin clearance. Since the haemodynamic parameters, pulmonary gas exchange variables and haematocrit were distributed within narrow ranges, we regard the temporal microcirculatory variability obtained here as normal in this experimental situation, and consider the porcine model well suited for further studies concerning renal microcirc

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb03320.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Closed‐loop control of atracurium‐induced neuromuscular blockade by a model‐based adaptive feedback algorithm is described. Mean offsets (± s.d.) from setpoints at 50, 70 and 90% neuromuscular blocks using the Relaxograph® were 1.1 ± 1.3, 0.2 ± 0.7 and 0.1 ± 0.4%, respectively. Correspondingly, the mean steady‐state rates of infusion of atracurium were 0.20 ± 0.06, 0.25 ± 0.03 and 0.39 ± 0.10 mg ‐ kg‐1‐ h‐1. The described controller provides reasonable control of atracurium dosing at different degrees of neuromuscular blockade. It gives a solution to the problem of adapting pharmacokinetic and pharmacodynamic data to individuals when using population mean data as starting

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb03321.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Diltiazem ‐ a calcium entry blocker ‐ was tested in a porcine model under continuous chlormethiazole‐pancuronium anaesthesia as protection against renal failure following 60 min of renal ischaemia. Fourteen pigs were randomly allocated to one experimental (diltiazem and ischaemia) and one control group (only ischaemia) (n = 7 in each). Diltiazem was administered as a continuous intravenous infusion started before the ischaemic insult. In two additional animals diltiazem was given but ischaemia was not induced. The postischaemic renal cortical microcirculation was simultaneously investigated in four different regions in the left kidney during the first 4 h of reperfusion. Laser Doppler flowmetry (LDF) was performed in two different regions and measurement of tissue oxygenation was done in two other regions. In the two animals treated with diltiazem without ischaemia, only minor variations in central haemodynamic and renal microcirculatory parameters were evident. In the control group (ischaemia), superficial renal cortical blood flow (Q decreased from 49 ± 11 (s.d.) arbitrary units at baseline to 24 ± 4 arb. units 4 h after start of reperfusion (P<0.05). Simultaneously, mean Pto2decreased from 4.5 ± 1.2 kPa to 2.4 ± 1.5 kPa (P<0.05) and the percentage of the measured Pto2values that were<0.6 kPa (Pto2) increased from 1 ± 2% to 19 ± 25% (P<0.05). In the experimental group Q decreased from 49 ± 8 arb. units at baseline to 27 ± 10 arh. units 4 h after start of reperfusion (P<0.05). Simultaneously, mean Pto2decreased from 4.6 ± 1.3 kPa to 3.2 ± 2.0 kPa (P<0.05) and L‐Pto2increased from 0 to 18 ± 23% (P<0.05). No significant differences in the renal microcirculatory parameters were found between control and experimental groups at baseline or 4 h after start of reperfusion. The postischaemic reduction (P<0.05) in inulin clearance during the investigated period was also unaffected by diltiazem. Thus, we conclude that intravenous pretreatment with diltiazem, which was used in this experimental porcine model, has no beneficial influence on either superficial renal cortical microcirculation or on recovery of inulin clearan

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb03322.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY