摘要:

Using the multiple inert gas elimination technique, ventilation/perfusion (V/Q) relationships were studied in an experimental porcine model of the early Adult Respiratory Distress Syndrome (ARDS) to establish the nature of the increased venous admixture. Six animals served as controls and revealed no major changes apart from a 10% decrease in cardiac output during the 4‐h observation period. All control animals showed a shift to a higher mean V/Q of perfusion (Qmean) and a maintained log standard deviation (Qsd) throughout the experiment. The distribution was unimodal and centered around a V/Q ratio of 1.0. The share of perfusion to V/Q ratio<0.005 (i.e. true shunt, Q) remained unchanged at 6–7% of cardiac output. Nine animals, given a continuous infusion ofE. coilendotoxin, showed a significant decrease of 53% in cardiac output (Q) at 4 h. Mean pulmonary artery pressure (MPAP) showed a 2‐phase reaction with a peak level at 0.5 h, and a second gradual increase from 2 h onwards. Venous admixture doubled at 0.5 h, after which it declined but remained elevated throughout the observation period. All endotoxin animals showed a shift in perfusion to a higher Qmeanwith a significantly wider Qsdat 0.5, 2 and 4 h. The distribution was unimodal and centered around a V/Q ratio of 1.0. True shunt was unchanged at 6–7% of cardiac output throughout the study. The increase in venous admixture in this experimental ARDS model is consequently explained by the widening of the V/Q scatter and is due to a perfusion shift to lower ventilation/perfusion ratios rather than to an increase in tru

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02980.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The development of atelectasis and effects on gas exchange during enflurane anaesthesia in nitrogen/oxygen or nitrous oxide/oxygen (inspired oxygen fraction 0.4) were studied in 16 lung‐healthy patients (mean age 49 years). Awake, no subject displayed atelectasis as assessed by computed x‐ray tomography of the thorax. Pulmonary gas exchange, studied by multiple inert gas elimination technique, and blood gases were normal. After 10 min of enflurane anaesthesia in nitrogen/oxygen, 14 of 16 subjects had developed atelectasis. After 30 min of enflurane anaesthesia in nitrogen/oxygen or nitrous oxide/oxygen, all patients had developed atelectasis, and a further increase was observed after 90 min of anaesthesia to approximately 5% of the intrathoracic area. There was no difference between the two anaesthesia groups. In the nitrogen group, shunt rose to a maximum of 5.8% at 30 min of enflurane anaesthesia, with a significant reduction to the initial anaesthesia level after 90 min of anaesthesia (3.4%). Perfusion of poorly ventilated lung regions (low VA/Q) averaged 4–5% and did not vary significantly during the anaesthesia. In the nitrous oxide group, shunt increased to 6.3% after 90 min of anaesthesia, and there was a parallel decrease in perfusion of low VA/Q regions. The findings suggest that besides prompt collapse of lung tissue during induction of anaesthesia, absorption of gas from closed‐off or poorly ventilated regions takes place and further increases the atelectat

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02981.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The serum cortisol and blood glucose concentrations were followed for up to 2 h after 35 transurethral prostatic resections performed under epidural anaesthesia. No significant variation in either of these levels was recorded in connection with the seven operations during which there was no disturbance of the fluid balance, or the seven where there was elevation in the central venous pressure indicative of intravenous fluid overload. In contrast, both the serum cortisol and the blood glucose level showed a significant increase in the nine patients with a blood loss of more than 800 ml, and in the nine recording absorption of irrigant in excess of 300 ml and immediate development of hyponatraemia. On the other hand, this response did not occur in the three patients with irrigant absorption where hyponatraemia developed with a delay of at least 20 min. These results suggest that the effect of surgery on the serum cortisol and blood glucose levels may be modified by disturbances of the fluid balance developing in the course of the operation.

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02982.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

In 20 patients subjected to craniotomy for supratentorial cerebral tumours, the haemodynamic changes during halothane and neurolept anaesthesia were evaluated by measuring mean arterial blood pressure (MABP) and cerebral arterio‐venous oxygen content differences (AVDo2) repeatedly during the operation. Ten patients were given 0.5% halothane anaesthesia and ten patients neurolept anaesthesia. MABP, AVDo2and Paco2were measured after induction of anaesthesia, before and after incision, after opening and closure of the dura, at the time of extubation and 1 h later. Concerning MABP and Paco2, no significant difference between the two groups was found. In both groups an increase in MABP was observed after incision (P<0.01 in the neurolept group andP<0.05 in the halothane group) and in the neurolept group after extubation (P<0.01). In both groups a decrease in AVDo2was observed after incision (P<0.01) and after extubation (P<0.01 in the neurolept group andP<0.05 in the halothane group). During the operation AVDo2values were significantly higher in the neurolept group (P<0.05). The results indicate that even a moderate increase in MABP after incision during neuroanaesthesia affects AVDo2values, suggesting an increase in cerebral blood flow. The study suggests that autoregulation of cerebral blood flow might be better preserved during neurolept anaesthesia. A state of hyperperfusion of the brain after extubation was unveiled in both group

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02983.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The circulatory effects of epinephrine, added to local anesthetic, during epidural analgesia were compared between middle‐aged (52–65 years) and elderly (75–82 years) patients undergoing transurethral resection of the prostate. We used 10 ml of 1.5% lidocaine with or without 1:200 000 epinephrine. The plasma epinephrine concentration peaked 5–10 min after the injection in the patients who received epinephrine with anesthetic. There was no significant difference in the plasma epinephrine concentration between the two age groups. Epinephrine caused a significant increase in the heart rate and a significant reduction in the diastolic arterial pressure in both age groups. A significant reduction of the systolic arterial pressure, however, occurred only in the middle‐aged patients. Neither the plasma concentration of endogenous epinephrine, heart rate nor arterial pressure changed significantly in the patients who received plain lidocaine. We conclude that the increase in the heart rate and decrease in the diastolic arterial pressure induced by epinephrine when added to an analgesic may not be influenced by advancing age. In contrast, the reduction in the systolic arterial pressure caused by epinephrine may become less pronounced

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02984.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Spinal anaesthesia with 3 ml, 4 ml or 5 ml of plain 0.5%, bupivacaine was performed in three groups of 20 orthopaedic (ASA I) patients at the LIV‐V interspace. Patients aged less than 20 years or more than 60 years and those outside the normal range of body mass index were excluded. The spread of analgesia was greater in the 4‐ml and 5‐ml groups compared to the 3‐ml group at each testing time (P<0.05). The mean maximum cephalad spread of pinprick analgesia (± s.d.) 60 min after injection was significantly higher (P<0.05) in the 4‐ml group (T10 ± 3.2) and in the 5‐ml group (T10 ± 2.7) than in the 3‐ml group (T12 ± 2.1). The interindividual variability of the cephalad spread of analgesia was greater in the 4‐ml and 5‐ml groups compared to the 3‐ml group (P<0.05). The degree of motor block was higher in the 5‐ml group than in the 3‐ and 4‐ml groups at 5 and 15 min after injection. In seven patients the first sign of motor block was the patient's inability to flex the ankle, rather than inability to raise an extended leg as was the case in the other patients. In all patients satisfactory anaesthesia for surgery of the

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02985.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The arterial to end‐tidal Pco2difference, Paco2‐Pe,co2, was measured at four different stages during coronary artery bypass grafting in 43 patients: 1) before sternotomy; 2) after sternotomy, sternum retracted; 3) after bypass, sternum still retracted; 4) sternum closed. Mean Paco2‐Pe,co2initially was 0.6 kPa and changed scarcely at all during the procedure. There were, however, some moderate individual changes in Paco2— Pe,co2during surgery, the range of changes compared to the initial value being from — 1.4 to + 1.3 kPa. The standard deviations for the changes from stage to stage were 0.3–0.4 kPa. Paco2— Pe,co2changed by more than 0.5 kPa on only 12 occasions in ten patients. The limitations of Paco2— Pe,co2as an index of the alveolar deadspace fraction and the efficiency of ventilatio

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02986.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The effects of halothane and thiopental on the respiratory efferent activities in the phrenic, recurrent laryngeal and hypoglossal nerves were studied in decerebrate, paralyzed and artificially ventilated cats. Inhalation of halothane (2%, 90 s) and intravenous injection of thiopental (2–3 mg/kg) produced a similar change in the breathing pattern, characterized by an increase in respiratory frequency and a decrease in the respiratory burst discharge in the three nerves studied. Depression of the respiratory activity was greatest in the hypoglossal nerve, intermediate in the recurrent laryngeal nerve, and least in the phrenic nerve. Both drugs diminished the whole power spectral densities of the three nerves. Thiopental selectively attenuated the high frequency peaks of these spectra and shifted the peak frequencies to lower values. Bilateral section of the vagus and carotid sinus nerves had no effect on the action of thiopental on the respiratory neural activities, whereas it decreased, but did not eliminate, the action of halothane. The present results demonstrate that both halothane and thiopental produce a selective depression of the upper airway motor activities, with stronger effects on the hypoglossal nerve. Effects on the peripheral receptors and the central respiratory drives differ between the two drug

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02987.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The effects of epidural analgesia on plasma calcitonin gene‐related peptide (CGRP) values during and after hysterectomy were investigated in 14 healthy patients. In seven patients who received general anaesthesia alone for pelvic surgery, there were no significant changes in plasma CGRP concentrations. In the remaining patients, who received extensive epidural blockade in addition to general anaesthesia, there were again no significant changes in plasma CGRP values. This was in spite of profound sympathetic blockade, as shown by marked hypotension and a significant decline in plasma catecholamines. The epidural group of patients showed the expected attenuation of the glucose, cortisol and growth hormone responses to surgery. The results show that circulating CGRP is unlikely to be involved in the modulation of peripheral vascular tone during pelvic surgery under either general or epidural anaesthesi

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02988.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

A power spectral analysis of electroencephalograms (EEGs) was performed in 30 infants who underwent plastic surgery for cleft lip or cleft palate. The study was conducted to investigate whether there was a significant correlation between EEG changes and arterial halothane concentration in infants. The power spectral analysis of EEGs was performed by the fast Fourier transform (FFT). Arterial halothane concentration was measured with gas chromatography. The relationship between the changes in the power spectra of EEGs and the arterial halothane concentration was examined by means of a multivariate analysis. Prior to administration of halothane, two kinds of EEG patterns were discernible. In one pattern the peak of the EEG power spectra was seen in the slow wave band (slow wave group); in the other the peak of the power spectra was present in the fast wave band (fast wave group). In the occipital lead the multiple correlation coefficient and the index of determination of the slow wave group were 0.71 and 0.50, respectively, and those of the fast wave group were 0.78 and 0.61, respectively. A significant correlation was proved to be present between the normalized values of the EEG power spectra and arterial halothane concentration in the occipital lead. Therefore, the results of the present study suggest that the relationship between changes in the power spectra of EEGs in the occipital lead and arterial halothane concentration in infants can be expressed by means of multiple regression formulas.

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1989.tb02989.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY