摘要:

The duration of effect of vecuronium has previously been studied in paediatric patients only during inhalation anaesthesia. We therefore studied the age–related differences in duration of action after administration of 0.1 mg kg‐1of vecuronium in 66% N2O in O2, fentanyl anaesthesia without inhalation agents. Forty–nine children (2 wk–14 yr, ASA 1–2) were selected for study and divided into four groups according to age. Evoked EMG monitor (Relaxograph, Datex, Finland) was calibrated with hypothenar muscle recording. The completely restored first twitch (T1) level was used as reference for recovery calculations. In infants (age<1 yr) the onset time (68 s) was only 0.6–0.8 times that of older patients (P<0.01). In infants the duration of surgical relaxation to Tl 10% (42 min) and the recovery index (21 min) were 1.7–2.9 times longer than in older patients (P<0.01). It took 55 min from the beginning of recovery to full restoration of Tl in infants, compared with 20–24 min in 3–15–year–old children. Interestingly, the younger the child, the more rapidly train–of–four ratio recovered compared with T1 (P<0.01). Because of the age–dependent prolongation of vecuronium relaxation and spontaneous recovery in small children, the level of relaxation should be monitore

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02855.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb03000.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Vibration strain may be defined as the sum of all reactions of the human being to vibration exposure. This also includes the biomechanical behavior of particular parts of the body. Knowledge about these reactions is necessary in the field of occupational health and ergonomics. Biomechanical models, experimental methods, and results are presented. It can be shown that under vibration exposure with different conditions (body posture, vibration direction), the body parts are in resonance at varying frequencies, mainly in a low frequency range.

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb03001.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

No rational approach has evolved for selecting operating conditions for clinical application of high‐frequency ventilation (HFV). To this end, we divide our discussion of HFV into considerations of mechanics versus transport, and treat the latter as a constraint. After describing some of the phenomena that influence distending pressure (and its distribution) expressed across pulmonary tissues, we address the pressure costs per unit ventilation and the factors that influence them. This narrowly defined approach leads to some fundamental strategies, compromises, and dilemmas. In particular, consideration of the mechanical interaction of the lung and chest wall leads to a paradox, and points out that the influence of the chest wall upon phasic regional lung distension is not well understoo

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb03002.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb03003.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The duration and possible accumulation of atracurium and pancuronium were studied in 59 patients (29 anephric and 30 normal) anaesthetized with 0.5% halothane in O2/N2O and supplemented by fentanyl. Equipotent doses of atracurium (0.5 mg–kg‐1) and pancuronium (0.1 mg–kg‐1) were given for intubation. Atracurium had a lower potency in anephric patients. The duration (first twitch response (TI) return to 20% of control) for atracurium was 28 min in anephric and 36 in normal patients. The corresponding mean times for pancuronium were 171 and 123 min, but with a very wide variation (range 20–380 min and 45–360 min, respectively). The duration of up to 8 incremental doses of atracurium (0.1 mg kg‐1) was 27 29 min in normal patients and of up to 13 increments was 25–34 min in anephric patients. Pancuronium (0.015 mg kg‐1) was given in a maximum of 4 increments. In normal patients the mean durations were 40–56 min, and in anephric patients 65–100 min. The duration of pancuronium, but not of atracurium, was prolonged with repeated injections (up to 2.7 times) in anephric patients. After pancuronium the spontaneous recovery was significantly slower in anephric patients, while the induced recovery was rapid and reliable in all groups. We conclude that atracurium is a safe and reliable muscle relaxant in normal and anephric patients, while pancuronium in both groups has a disturbing variation in duration and, in addition, signs of significant accumulation in anephric patients. The use of a nerve st

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02858.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Prior studies of gas transport mechanisms are reviewed with the aim of using these results to suggest improvements over current methods of ventilation. These concepts are cast in a simpler framework that more clearly identifies those factors that limit the rate of gas transport under conditions typical of HFV. One simplification introduced simulates the enhancement of molecular diffusion due to the movement of gas back‐and‐forth through regions of varying cross‐sectional area. The region of the lung that currently poses the greatest resistance to gas transport is represented by those airways having diameters in the range of 1.0 to 2.5 mm. This suggests that new efforts should be devoted to better understanding the nature of transport in this zone and to the development of variations in the method of ventilation that have the greatest influence

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb03004.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Spinal anaesthesia with 2, 3 or 4 ml of glucose–free 2% lignocaine was studied in 64 patients undergoing transurethral surgery of the bladder. Cephalad spread of analgesia, onset time, duration of analgesia, duration of motor block, quality of analgesia, and the cardiovascular effects were assessed. Two ml of 2% lignocaine was insufficient to produce reliable analgesia. Three ml provided sufficient analgesia in most of the patients, but 4 ml was needed to guarantee sufficient analgesia in all patients. Onset times for analgesia and motor block were 10–20 min. After 4 ml the median and interquartile values were: maximum cephalad spread: T8, (T10–T5); time from injection to regression of analgesia to T11: 84 min, (60–103 min); duration of complete motor block: 90 min, (60–120 min). All patients in the 3–ml and 4–ml groups developed complete motor block. There was a positive correlation between the dose and the duration of analgesia and motor block. A positive correlation, although weaker, was also seen between the dose and the maximum cephalad spread of analgesia. There was an inverse relationship between the cephalad spread of analgesia and the duration of motor block. Falls in systolic blood pressure>30% were noted in seven patients in whom the cephalad spread of analgesia was higher than in the rest of the patients. Spinal anaesthesia with glucose–free 2% lignocaine in doses of 3–4 ml provides reliable analgesia for transurethral surge

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02859.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

A liquid flow visualization technique was used to identify the location of neutrally buoyant bead clouds injected into airway models during flows simulating high frequency intermittent jet ventilation (HFIJV) in neonatal lungs. The motions of these bead clouds show that the convective or bulk mixing that occurs during HFIJV is made up of two parts; a turbulent convective exchange with the atmosphere caused by the jet in the trachea and a streaming motion along the airways driven by an interaction between the jet and the expansion and contraction of the airways due to their compliance. These convective streaming motions combine with molecular diffusion to produce augmented diffusion which transports O2and CO2between the trachea and the peripheral alveoli. Optimizing HFIJV (as well as other forms of HFV) depends on maximizing these airway convective streaming flows which depend on many more lung and fluid mechanical parameters than are necessary to describe conventional mechanical ventilation.

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb03005.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The isolated perfused rat heart was used to study the myocardial effects of glucocorticoid methylprednisolone sodium succinate (MPSS 0, 100, 500 and 1000 mg/1) in normoxic conditions. Various physiological variables including coronary flow rate (CFR), left ventricular developed pressure (LVDP), dP/dTmax, dP/dTmix, and heart rate (HR) were assessed. At the end of the perfusion period the hearts were freeze clamped and analyzed for tissue content of calcium and various metabolites. MPSS (500 mg/1) resulted in vasodilatation and inotropic stimulation. An increase was found in CFR (+17% 4), LVDP (+ 6% 1), dP/dTmax, (+13% 2), dP/dTmix, (+ 9% 3); (P<0.05). Heart rate was depressed (– 14% 2,P<0.05). MPSS (100 mg/1) had no effect on CFR or contractility. MPSS (1000 mg/1) resulted in a transient vasodilatation and a progressive myocardial depression. MPSS perfusion (100 and 500 mg/1) increased the adenine nucleotide pool and at all concentrations MPSS elevated the myocardial content of lactate. We conclude that in normoxic conditions there is a bell–shaped curve of myocardial inotropic stimulation by the glucocorticoid hormone, and also a stimulation of metabolism possibly by increased cellular supply of substra

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02861.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY