Effects of occupational use of vibrating tools in the autonomic, central and peripheral nervous system

OBJECTIVES

The objective of this study was to clarify the autonomic, central and peripheral nervous effects of vibrating-tool operation.

METHODS

The ECG R-R interval variability (CVRR), including the C-CVHF, C-CVLF (two component CVs of the CVRR reflecting parasympathetic and sympathetic activities, respectively) and the power spectral densities (PSDHF and PSDLF) after autoregressive analysis, short-latency somatosensory evoked potentials (SSEP), distribution of nerve conduction velocities (DCV), and median and radial nerve conduction velocities (NCVs) were measured in 17 vibrating-tool operators and the same number of age-matched control subjects. Some of the operators complained of white finger even in summer as soon as they arrived at the cold workplace.

DESIGN

The significance of the differences in neurophysiological data between the exposed and unexposed groups and the associations between these data in the former were investigated.

RESULTS

The CVRR, C-CVHF and PSDHF were significantly lower in the vibrating-tool operators than in the matched controls. The N9-N13 interpeak latency of the SSEP, i.e., conduction time of the cervico-spinobulbar pathway, in the operators was significantly prolonged as compared with the controls; the faster velocities of the DCV and the NCVs were significantly slowed in the operators. The N9-N13 interpeak latency in the operators was significantly correlated with the C-CVHF.

CONCLUSION

Complex stressors of local vibration, cold, noise and heavy work, seem to affect the cervico-spinobulbar, parasympathetic and peripheral nerve functions. Also, parasympathetic hypofunction may imply a consequence in brainstem pathology induced by cold exposure in addition to vibration.

Pancuronium increases pulmonary arterial pressure in lung injury

We studied 25 mongrel dogs who were anaesthetized and their lungs ventilated for investigation of the effects of pancuronium on pulmonary arterial pressure (PAP) in the normal lung, in oleic acid-induced lung injury and in lung injury with hypoxaemia. In the normal lung, PAP was not affected by pancuronium. During lung injury, however, PAP was increased from 21.5 (SD 2.8) to 24.6 (4.2) mm Hg (P < 0.01) and from 22.0 (4.2) to 27.0 (5.8) mm Hg (P < 0.01) after pancuronium 0.08 mg kg-1 and 0.16 mg kg-1, respectively, and from 26.0 (2.9) to 37.1 (3.1) mm Hg after pancuronium 0.16 mg kg-1 when hypoxaemia was present (P < 0.01). The increase in PAP induced by pancuronium was associated with increases in cardiac output and pulmonary vascular resistance. Pretreatment with phentolamine attenuated the pancuronium-induced increase in PAP. The increase in PAP induced by pancuronium was also reduced by vagotomy. If these results in dogs are relevant clinically, then pancuronium should be avoided as a neuromuscular blocker in lung injury.

[Lateralization in dissociated vertical deviation with flash visual evoked potentials]

Lateralization, suggesting misrouting of optic nerve fibers in albinism, was examined by the flash visual evoked potentials (flash VEP) test in dissociated vertical deviation (DVD). Eighteen cases of DVD were studied and compared with 5 cases of X-recessive ocular albinism and 4 normal controls. Full-field monocular and binocular stimulation was employed with electroencepharograph electrodes on O1 and O2 (10/20 system), and the latency of P100 was statistically analysed with two-way analysis of variance. The difference in the P100 latency between contralateral and ipsilateral stimulation was significant (p < 0.05) in albinism, but not in DVD and normal controls. Therefore, DVD is probably not associated with misrouting of optic nerve fibers.

[Landau-Kleffner syndrome: relationship between aphasia and electroencepharographic changes]

The relationship between aphasia and electroencephalogram (EEG) findings was studied in 2 patients with Landau-Kleffner syndrome. The appearance of diffuse spike and wave complexes almost always preceded the exacerbation of aphasia. Prior to the improvement of aphasia, EEG abnormality localized into the temporal region, and subsequently disappeared.

Biosynthesis of the acetylenic compounds in cultured cells of Asparagus officinalis from D- and 13C-labelled phenylalanines

Studies on the biosynthetic pathway of acetylenic compounds, 4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]phenol and its related compounds, in cultured cells of Asparagus officinalis L. (Liliaceae) revealed that all of the 17 carbon atoms in their skeletons are supplied by phenylalanine. It is also concluded that p-substituted phenylacetylenic moieties (the C6-C2 unit) in these compounds are derived from C6-C3 shikimate pathway metabolites via phenylalanine. As a working hypothesis concerning the C6-O-C3 unit formation, a spirotetrahydrofuran type intermediate is predicted.

Hemodynamics and oxygen consumption during warm heart surgery

We compared the effects of normothermic cardiopulmonary bypass (CPB) with those of hypothermic CPB in patients who underwent coronary artery bypass grafting (CABG) with respect to hemodynamics and oxygen balance. The patients in our study were divided into two groups according to temperature during CPB: systemic normothermia combined with warm blood cardioplegia (group W,n=36) and systemic hypothermia combined with cold crystalloid cardioplegia (group C,n=26). In group W, the use of directcurrent (DC) defibrillators was less frequent after release of the cross clamp, and the duration of CPB and of reperfusion was shorter. After CPB, the cardiac index and arterial pressure were higher and the dosages of dopamine were lower in group W than in group C. The serum glucose level during and after CPB was lower and the base excess during CPB was higher in group W than in group C. Oxygen consumption ([Formula: see text]) was unchanged throughout the operation in group W, while it decreased during CPB and increased at the end of surgery in group C. The oxygen extraction ratio (ERo2) increased during CPB in group W, while it was unchanged throughout the operation in group C. Mixed venous oxygen saturation ([Formula: see text]) was maintained above 65% during and after CPB in group W and group C. Our results showed that normothermia may be superior to hypothermia during CPB with respect to recovery of cardiac function and avoidance of hyperglycemia. The whole-body oxygen demand-supply balance may be preserved during normothermic as well as hypothermic CPB.

Biosynthesis of acetylenic compounds in cultured cells of Asparagus officinalis from [1-13C]- and [U-13C] Glucose

The biosynthetic pathway of phenolics with an acetylenic group, 4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]phenol (1) and its related compounds, isolated from suspension-cultured cells of Asparagus officinalis L. (Liliaceae), was studied in feeding experiments using [1-13C]- and [U-13C] glucose. Analyses of the 13C-NMR spectra of the methyl ether and acetate of the 13C-labelled species of 1 indicated that the aromatic rings at both ends of the molecule are formed from shikimic acid. It was also assumed that the acetylenic carbons in the C5 chain could be incorporated together with its adjacent aromatic ring through any phenethyl class compound derived from phenylpropanoids, and the propenylene carbon through glycolysis metabolites with C3 carbon units.

Which blood gas caused the brain damage?

In order to analyse the effects of various physiological parameters including blood gas data on the cerebral oxygenation, we developed a model to enable us to estimate PtO2 (tissue PO2) from these physiological parameters. This model was applied successfully to a set of blood gas data of a patient who had brain damage after cardiac surgery. Contrary to the original impression, we concluded that a very low PaCO2 of 13 mmHg towards the end of CPB was the most likely cause of his damage.

[Statistical analysis of anesthesiologists' thinking patterns concerning regulation of the blood pressure and the concentration of inhaled anesthetics]

During surgery, the anesthesiologists adjust the concentration of inhaled anesthetics according to the change in blood pressure in order to achieve good control of anesthesia. Usually the thinking patterns of individual anesthesiologists differ from one to another. We obtained data from each anesthesiologist's thinking pattern concerning the regulation of blood pressure and the concentration of inhalational anesthesia. These patterns were analyzed statistically and compared for individual anesthesiologist. The results showed that anesthesiologists' regulation rules were formed independently of the 3 drugs and were specific to individuals. Some trends depending on institution were observed, but no statistically significant difference was found.

[Anesthesia for SUMO wrestlers]

We anesthetized 34 sumo wrestlers. All patients were male. Average age was 21.1. Their height was 181.9 +/- 4.5 (mean +/- SD) cm, and they weighted 135.2 +/- 16.9 kg. Anesthetic methods used were spinal anesthesia alone in 17 patients, general anesthesia alone in 9, general anesthesia + epidural anesthesia/or spinal anesthesia/or axillary block in 8. The preoperative data showed findings common to obese patients; liver dysfunction, abnormal blood sugar, and abnormal ECG such as ST depression or left ventricular hypertrophy. For intubation, fiberscopy was required in one patient, and almost all patients required high FIO2, otherwise SaO2 decreased. For spinal anesthesia or epidural anesthesia, we needed long needles of 8 to 15 cm.

Effects of cementum-impregnated gelatine membrane on early healing following periodontal flap surgery

The purpose of this study was to investigate the initial healing response of surgically flapped periodontal tissues in the presence of gelatine membrane compounded with particles of cementum. Four monkeys with no periodontal disease were used in this experiment. Full thickness flaps were raised and recession type defects were created on the buccal side of the maxillary lateral incisors and second premolars. Exposed root surfaces were thoroughly curetted, and composite cementum-impregnated membranes placed directly onto planed root surfaces. Flaps were then sutured back to the original position. Animals were sacrificed at 2, 4, 7 and 10 post-surgical days, and block specimens including the tooth, gingiva and bone were subsequently processed for light and electron microscopy. The resultant analysis revealed that gelatine membranes were partially resorbed at 2 days post-surgery and completely resorbed by 10 postoperative days. In the early stages of gelatine resorption, most liberated cementum particles accumulated on planed dentin surface but some became demineralized within the surgical wound. Cementoblast-like cells with well-developed rough endoplasmic reticulum appeared on the root surface 7 days following surgery. Newly synthesized collagen fibrils aligned parallel to the root surface were seen at 10 post-surgical days. The results suggest that the newly developed composite membrane enhances the formation of new periodontal attachment.

Acetylenic compounds isolated from cultured cells of Asparagus officinalis

Three new acetylenic compounds, compounds I, II and III were isolated from the cultured cells of Asparagus officinalis L. (Liliaceae) and their structures identified as 1-methoxy-4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]-benzene, 4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]phenol and 4-[5-(4-hydroxyphenoxy)-3-penten-1-ynyl]phenol, respectively, from chemical and spectral analysis.

[Analysis of the anesthesiologists' action patterns concerning regulation of the blood pressure and the concentration of inhalational anesthesia]

The action pattern of each anesthesiologist is different. We have developed a computer program simulating anesthesiologists' action patterns during operation and have extracted the action patterns of anesthesiologists using a computer program. The simulation program was designed to gather data on anesthesiologists' response to the change in blood pressure. The results indicate that the action pattern differs significantly from one anesthesiologist to another in responding to the change in blood pressure. That of one particular anesthesiologist remained the same, regardless of the agent used. His action pattern is directed only by the value of MAC and according to his own personal principle.

Respiratory muscle pressure analysis in pressure-support ventilation

The extent to which respiratory muscles are exerted during partially supported ventilation is difficult to differentiate, because these muscles and the ventilator work simultaneously to produce ventilation. We have developed a new method for determining the pressure developed by the respiratory muscles in partially supported ventilation. In seven patients on pressure-support ventilation (PSV), pressure, flow, and lung volume change were measured at the airway opening. Various PSV levels (0-15 cmH2O) were applied to each patient in random order. By utilizing a model of respiratory mechanics, we calculated the pressure developed by the respiratory muscles and the inspiratory work performed by the muscles from the measured parameters by use of the resistance and elastance of the respiratory system obtained during controlled ventilation. Increasing PSV from 0 to 15 cmH2O modulated the resultant breathing pattern, i.e., increasing tidal volume and decreasing respiratory rate. The respiratory muscle pressure, although less negative, had a shape that corresponded to the shape of airway occlusion pressure at each PSV level, and both pressures decreased concomitantly with increasing PSV. The respiratory muscle work progressively decreased with increasing PSV. This analysis enabled clear and continuous quantifications of the respiratory muscle force generation and inspiratory work during partially supported ventilation.

[Single dose toxicity studies of lactitol (NS-4) in mice and rats]

The single dose toxicity studies of lactitol, a hepatic encephalopathy drug, were performed in ddY mice and SD rats of both sexes by administering the drug orally, intravenously or subcutaneously. The drug was administered as a single dose followed by a 14-day observation. Oral LD50 values of lactitol were estimated to be between 23 and 30 g/kg in male mice, approximately 30 g/kg in female mice, and more than 30 g/kg in male and female rats. Lethal dose was more than 10 g/kg intravenously and subcutaneously in mice and rats of both sexes. The signs of toxicity in mice and rats observed following the administration of this drug included the following: decreased spontaneous movement [p.o., i.v., s.c.]; diarrhea, oligopnea or prone position, transient decreased body weight [p.o]. There were no treatment-related changes in gross examination. Based on these results, it was found that lactitol had a very low acute toxicity when administered by a single dose method in mice and rats.

[Two cases of unexplained pupillary dysfunction after cardiac surgery in severely diabetic patients]

We experienced two cases of unexplained pupillary dysfunction in severely diabetic patients after cardiac surgery. In both patients, marked bilateral dilatation of the pupils and the absence of light reflex were recognized immediately after leaving the operating room. The pupillary dysfunction, however, was not accompanied by other neurological deficits, and the pupil sizes returned normal spontaneously by 24 hours. We speculated that impaired peripheral perfusion during cardiopulmonary bypass caused transient tissue ischemia on the basis of microangiopathies of severe diabetes mellitus. Bilateral ciliary ganglia were thought to be most susceptible to the impaired perfusion and responsible for the pupillary dysfunction.

[The effects of incentive spirometry on pulmonary functions]

The effects of incentive spirometry on pulmonary functions were studied in 46 normal adults of advanced age ('N' group) and 42 patients with chronic pulmonary emphysema ('E' group). Subjects of the both groups carried out deep breathing exercises by using incentive spirometry, 'Souffle', for five minutes, five times daily for four weeks. Pulmonary functions and arterial blood gases were measured at the start of exercise program, and at two and four weeks after the start. Both groups showed significant increases in VC, FEV1.0, peak expiratory flow, the flow at 75 percent VC (V75), maximal voluntary ventilation and PaO2, and a significant decrease in A-aDO2 at both two and four weeks after the start. In addition, V25 increased significantly in 'E' group. It is concluded that 'Souffle' is one of the useful preoperative respiratory managements for elderly patients and those with chronic pulmonary emphysema.

Pulmonary capillary pressure measured with a pulmonary arterial double port catheter in surgical patients

We developed a pulmonary artery (PA) double port catheter technique for reliable clinical measurements of pulmonary capillary pressure (Ppc). In seven elective surgical patients, the PA double port catheter with the second PA port 1 cm proximal to the balloon was inserted. The two PA ports, connected to identical pressure measuring systems, provided the pulmonary arterial pressures (Ppa) distal and proximal to the balloon. After general anesthesia was stabilized, the two Ppas were measured simultaneously during a PA occlusion maneuver during 10 s of apnea. The instant of occlusion was determined precisely as the time when the two Ppa traces sharply diverged. A single exponential equation was fitted to the segment of distal Ppa tracing starting 0.3 s after the instant of occlusion. Ppc was determined as the value of the exponential fit extrapolated to time 0. In six of seven patients, PA occlusion occurred consistently in the early systolic phase regardless of the timing of balloon inflation. Mean Ppa, Ppc, and pulmonary arterial wedge pressure were 16.6, 11.8, and 7.6 torr. The ratio of venous to total resistance ranged from 0.37 to 0.54 (mean:0.46). We conclude that this technique is clinically feasible and valuable in precise definition of the instant of PA occlusion. By defining PA occlusion consistently, this technique can provide reliable Ppc estimation in the clinical settings.

Natural frequency/damping coefficient relationship of the catheter-manometer system required for high-fidelity measurement of the pulmonary arterial pressure

Using a digital simulation method, we analyzed the relationship between natural frequency (fn) and damping coefficient (Zeta) of the catheter-manometer system required for high-fidelity measurement of the pulmonary arterial pressure. The pulmonary artery pressure waveform was obtained with a catheter-tip transducer and it was fed into a dynamic simulator programmed on a computer. The original waveform and the output of the simulator were compared and judged visually for the fidelity. From this analysis, the combination of fn and Zeta was obtained and was plotted on a fn-Zeta diagram. It showed as an area, which was convex on the left side and open on the right side. The left-convex endpoint was located at a damping coefficient of about 0.7. At a lower heart rate, this area was extended to the lower frequency side, while, at a higher heart rate, this area was limited to the higher frequency side. The fn-Zeta diagram was also constructed theoretically by calculating the relations between natural frequencies and damping coefficients of a second order system with the amplitude and phase error tolerance set at +/-5% respectively.

[A graphic presentation of the anesthesiologist's action pattern]

The action patterns of anesthesiologists are different among individuals. We have developed a graphic presentation system for anesthesiologists' action patterns using computer graphics. The resulting representation is called "thought map". Data were obtained from 6 anesthesiologists (4 certified instructors and 2 new doctors) with a time interval of 2 years, regarding the use of 3 drugs (enflurane, sevoflurane and isoflurane). The "maps" were compared among individuals, dates and drugs. The following results were obtained: 1) significant differences existed among individuals, 2) during the 2-year time interval, 2 new drugs were introduced and the practice pattern alterations were seen in the maps, 3) for the 2 new anesthesiologists, the maps show the process of professional knowledge acquisition. We propose an index ("immovable rate"), denoting the proportion of the map where concentration of the drug didn't change. This index is to be used for evaluating human thinking.

Cardiac autonomic dysfunction in rotogravure printers exposed to toluene in relation to peripheral nerve conduction

The autonomic nervous effects of toluene remain less clear. To clarify this neurotoxicity, ten rotogravure printers and the same number of age-matched unexposed controls were examined, by using the coefficient of variation in electrocardiographic R-R intervals (CVRR), the distribution of nerve conduction velocities (DCV) and the maximal motor and sensory nerve conduction velocities (MCV and SCV) in the median nerve. Also, the C-CVHF and C-CVLF (two component CVs of the CVRR reflecting parasympathetic and sympathetic activities, respectively) were computed from component spectral powers using autoregressive spectral and component analyses. These printers had been exposed to toluene (estimated exposure levels of toluene at 83 ppm) for 1-36 years. The CVRR and C-CVHF were significantly lower in the printers than in the controls. No significant difference between the printers and the controls was found in either any DCV parameters or the SCV in the forearm, except the MCV and the SCV in the palm. In the light of previous work on the brainstem/hippocampus damages due to toluene, these data suggest that toluene causes potential damages in the central autonomic nervous system, mainly parasympathetic hypoactivity.

Report on the computer software contest at the 39th Congress of the Lapan Society of Anesthesiology

We held another computer software contest at the 39th Congress of the JSA. The aim and procedure were similar to those for the first contest in 1991. Twenty-four softwares entered the contest; the machines are divided approximately two to one ratio between NEC PC9801 series and Macintosh. We received donations of 2 million yen worth of instruments and goods for prizes plus some cash. They were given away to those who made entries for the contest.Most of these programs have been registered as free softwares at various computer networks. A plan is under way to distribute them in diskette forms.

[Simulation in anesthesia]

Simulation in anesthesia is reviewed. Its aim includes education/training, analysis of phenomena, explanation or interpretation of phenomena and instrument checks. It deals with pharmacokinetics/pharmacodynamics of inhalational and intravenous agents, respiration and circulation, action and behavior of anesthesiologists and income analysis. Simulations are accomplished mainly by using computers, yet few use physical models or a physical model combined with computers. For writing this review, CD-ROM's of Medline data were used. Problems in searching literatures through this route are discussed. Finally, the problem of the distribution of softwares is also discussed.