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Biomedical subjects

L Tokics

Publications and source records attributed to L Tokics.

At least 19 recordsLinked to original sources
PubMed1999

Acute quadriplegic myopathy following autologous peripheral blood stem cell transplantation for breast cancer.

Autologous peripheral blood stem cell transplantation (APSCT) is increasingly used in the treatment of breast cancer. We report a patient who experienced septic shock, and after treatment with antibiotics, high-dose corticosteroids and mechanical ventilation due to respiratory insufficiency, developed quadriplegia. Electroneurophysiological examination, as well as a muscle biopsy, showed a typical picture of acute quadriplegic myopathy with loss of thick filament proteins. This is, to the best of our knowledge, the first reported case of this complication following APSCT.

Acute Disease↗
PubMed1996

Influence of age on circulation and arterial blood gases in man.

BACKGROUND: Modern data on the influence of age on hemodynamic and blood gas data in healthy subjects are sparse, especially in middle aged or older subjects. Most measurements have been done in patients during major surgery or in intensive care when the patients have one or more failing organ systems. This study reports on hemodynamics, blood gases and blood volume in healthy patients prior to anesthesia and elective surgery. METHODS: A total of 116 subjects (92 males, 24 females) were investigated prior to anesthesia and elective surgery. No one had received any premedication or was taking regular medication. All subjects were in good physical condition, except for their surgical disease, and clinical examination and history did not reveal any sign of cardiopulmonary disease. Measurements were made of systemic and pulmonary vascular pressures, cardiac output, arterial blood gases and blood volume by 131I-Albumin distribution. RESULTS: Cardiac output, stroke volume, and blood volume correlated to body surface. Relating these variables to body size eliminated almost all differences between the male and female groups. These variables, as well as both systemic and pulmonary artery systolic vascular pressures, were affected by increasing age. Pulmonary capillary wedge and right atrial pressures were not influenced by age. PaO2 decreased with age from 14.0 kPa at 20 years to 11.3 kPa at 80, whereas PaCO2 was unaltered. No effect of light smoking was found on pulmonary circulation or arterial blood gases. Significant correlations were found between blood volume on the one hand and body size and age on the other hand, but not in regard to sex.

Adult↗
PubMed1996

V/Q distribution and correlation to atelectasis in anesthetized paralyzed humans.

Regional ventilation and perfusion were studied in 10 anesthetized paralyzed supine patients by single-photon emission computerized tomography. Atelectasis was estimated from two transaxial computerized tomography scans. The ventilation-perfusion (V/Q) distribution was also evaluated by multiple inert gas elimination. While the patients were awake, inert gas V/Q ration was normal, and shunt did not exceed 1% in any patient. Computerized tomography showed no atelectasis. During anesthesia, shunt ranged from 0.4 to 12.2. Nine patients displayed atelectasis (0.6-7.2% of the intrathoracic area), and shunt correlated with the atelectasis (r = 0.91, P < 0.001). Shunt was located in dependent lung regions corresponding to the atelectatic area. There was considerable V/Q mismatch, with ventilation mainly of ventral lung regions and perfusion of dorsal regions. Little perfusion was seen in the most ventral parts (zone 1) of caudal (diaphragmatic) lung regions. In summary, shunt during anesthesia is due to atelectasis in dependent lung regions. The V/Q distributions differ from those shown earlier in awake subjects.

Adult↗
PubMed1995

Lung function after open versus laparoscopic cholecystectomy.

Postoperative lung function and gas exchange were studied in 36 patients after cholecystectomy. Twenty-four of the patients underwent laparoscopic cholecystectomy while the remaining twelve were operated with open technique. Before surgery all patients had normal ventilatory volumes (forced vital capacity, FVC and forced expired volume in 1 s, FEV1) and normal gas exchange. Two hours postoperatively FVC was reduced to 64 +/- 16% (P < 0.05) of the preoperative level in the laparoscopic group and to 45 +/- 23% (P < 0.05) after open cholecystectomy. On the first postoperative day FVC was virtually normal in the laparoscopic patients (77 +/- 17% of preoperative level, NS), whereas the open surgery patients still had a decreased FVC (56 +/- 13% of preoperative, P < 0.05). FEV1 in the postoperative period followed the same course as FVC. Gas exchange was significantly impaired in the early postoperative period in all patients but no difference between the two groups was found. Two hours postoperatively PaO2 was reduced to 85% (P < 0.05) of preoperative value and PaCO2 had increased by 0.5 kPa (P < 0.05). The alveolo-arterial oxygen tension difference (PA-aO2) had increased by approximately 45% to a mean of 3.7 kPa (P < 0.05). On the first postoperative day gas exchange was still significantly impaired in the open surgery patients. Atelectasis detected by computed X-ray tomography of the lungs were found in both groups. However, the amount of atelectasis tended to be smaller in the laparoscopic group than in the open surgery patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

CT-assessment of dependent lung densities in man during general anaesthesia.

PURPOSE: We aimed to describe the frequency of atelectasis occurring during anaesthesia, to describe the size and pattern of the atelectasis, and to standardise the method of identifying the atelectasis and calculate its area. MATERIAL AND METHODS: Patients (n = 109) scheduled for elective abdominal surgery were examined with CT of the thorax during anaesthesia. RESULTS: In 95 patients (87%) dependent pulmonary densities were seen, interpreted as atelectasis. Two different types of atelectasis were found-homogeneous (78%) and non-homogeneous (9%). Attenuation values in histograms of the lung and atelectasis were studied using 2 methods of calculating the atelectatic area. CONCLUSION: On the basis of the present findings, we defined atelectasis as pulmonary dependent densities with attenuation values of -100 to +100 HU.

Adolescent↗
PubMed1994

Phrenic nerve stimulation during halothane anesthesia. Effects of atelectasis.

BACKGROUND: Atelectasis formation during anesthesia may be due to loss of respiratory muscle tone, in particular that of the diaphragm. This was tested by tensing the diaphragm by phrenic nerve stimulation (PNS) and observing the effect on atelectasis. METHODS: Twelve patients (mean age 48 yr) without preexisting lung disease were studied during halothane anesthesia. PNS was executed with an external electrode on the right side of the neck. Chest dimensions and area of atelectasis were studied by computed tomography of the chest. RESULTS: Right-sided PNS against an occluded airway at functional residual capacity reduced the atelectatic area in the right lung from 5.1 to 3.8 cm2. The atelectasis was reduced to 1.1 cm2 after application of positive end-expiratory pressure (PEEP) of 10 cmH2O and large tidal volumes but increased to 2.5 cm2 within 1 min after discontinuation of PEEP. Commencement of PNS immediately after PEEP prevented the atelectasis from increasing, the mean area being 0.9 cm2. In seven patients, in whom the trachea was intubated with a double-lumen endobronchial catheter the atelectatic area was smaller during PNS with an open airway than during positive pressure inflation of the lung with the same volume as inspired during PNS (3.5 and 5.2 cm2, respectively. CONCLUSIONS: The findings indicate that contracting the diaphragm in the anesthetized subject reduces the size of atelectasis.

Adult↗
PubMed1993

Analysis of lung density by computed tomography before and during general anaesthesia.

Pulmonary structure was analysed by means of computed tomography (CT) in 20 lung-healthy patients, relating tissue density to the attenuation value (AV) of a picture element. Regional density of pulmonary tissue (rlung) was determined using mean lung density in five regions of interest (ROI1-5) (sector method). Vertical and horizontal distributions of x-ray attenuation were analysed by density profiles, relating AV values to evenly distributed and normalised length scales. In group I (n = 12), CT-densitometry was obtained in awake, supine patients and after induction of general anaesthesia. In group II (n = 8), the effect of mechanical ventilation with positive end-expiratory pressure (PEEP, 1.0 kPa [10 cmH2O]) was studied. In the awake state, a vertical tissue density difference between the top and bottom of the lung was found in all patients, accounting for a mean of 0.235 g.cm-3 (right lung) and 0.199 g.cm-3 (left lung). Only minor changes were seen in the horizontal lung density profiles. After induction of anaesthesia, x-ray attenuation of ROI1-4 showed no significant differences when compared with the awake state. The basal lung areas (ROI5) revealed a significantly increased tissue density (P < or = 0.01), reaching mean values of 0.94 g.cm-3 (right lung) and 0.814 g.cm-3 (left lung). Similarly, vertical density profiles showed a markedly enhanced rlung of the bottom of the lung in all patients, interpreted as atelectasis. The amount of atelectasis accounted for 4.8 +/- 2.6% (right lung) and 4.7 +/- 2.1% (left lung) of the intrapulmonary area.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Atelectasis and lung function in the postoperative period.

Thirteen patients with healthy hearts and lungs, and with a mean age of 68 years, who were scheduled for lower abdominal surgery during isoflurane anaesthesia with muscular paralysis, were investigated with arterial blood gases, spirometry, pulmonary x-ray and computed tomography (CT) of the chest before and during anaesthesia, as well as during the first 4 postoperative days. Before anaesthesia, lung function and gas exchange were normal in all patients. Pulmonary x-ray and CT scans of the lungs were also normal. During anaesthesia, 6 of 13 patients developed atelectasis (mean 1.0% of intrathoracic transverse area in all patients). Two hours postoperatively, 11 of 13 patients had atelectasis and the mean atelectatic area was 1.8%. Pao2 was significantly reduced by 2.1 kPa to 9.8 kPa. On the first postoperative day, the mean atelectasis was unaltered (1.8%). None of the atelectasis found on CT scanning could be detected on standard pulmonary x-ray. Forced vital capacity (FVC) and forced expired volume in 1 s (FEV1) were significantly decreased to 2/3 of preoperative level. Pao2 was significantly reduced to less than 80% of the preoperative level (mean 9.4 kPa). There were significant correlations between the atelectatic area and the impairment in FVC, FEV1, and Pao2. Spirometry and blood gases improved during the succeeding postoperative days, and atelectasis decreased. No patient suffered from pulmonary complications, as judged from clinical criteria and pulmonary x-ray, in contrast to the findings of atelectasis in 85% of the patients by computed tomography.

Abdomen↗
PubMed1991

Influence of age on atelectasis formation and gas exchange impairment during general anaesthesia.

We have studied the effects of anaesthesia on atelectasis formation and gas exchange in 45 patients of both sexes, smokers and nonsmokers, aged 23-69 yr. None of the patients showed clinical signs of pulmonary disease, and preoperative spirometry was normal. In the awake patient, partial pressure of arterial oxygen (PaO2) decreased with increasing age (P less than 0.001) and the alveolar-arterial oxygen partial pressure difference (PAO2-PaO2) increased with age (P less than 0.001). Shunt, assessed by the multiple inert gas elimination technique, was small (mean 0.5%) and uninfluenced by age. However, there was an increasing dispersion (log SD Q) of ventilation/perfusion ratios (VA/Q) and increasing perfusion of regions of low VA/Q (VA/Q less than 0.1) with increasing age (P less than 0.001 and P less than 0.05, respectively). No patient displayed any atelectasis as assessed by computed x-ray tomography of the chest. During inhalation anaesthesia (halothane or enflurane) with mechanical ventilation, 39 of 45 patients developed atelectasis and shunt. There was a strong correlation between the atelectatic area and the magnitude of shunt (r = 0.81, P less than 0.001). Atelectasis and shunt did not increase significantly with age, whereas log SD Q and perfusion of regions with low VA/Q ratios did (r = 0.55, P less than 0.001 and r = 0.35, P less than 0.05, respectively). Awake, the major determinant of PaO2 was perfusion of regions of low VA/Q ratios, which increased with age. During anaesthesia shunt influenced PaO2 most, low VA/Q being a secondary factor which, however, was increasingly important with increasing age, thus explaining the well-known age-dependent deterioration of arterial oxygenation during anaesthesia.

Adult↗
PubMed1991

Radiospirometry V/Q.

Single photon emission computerized tomography (SPECT) of the lungs was used for topographical determination of V/Q ratios in anaesthetized-paralyzed subjects. Ventilation and perfusion were estimated from the distribution of an inhaled aerosol containing a radioactive isotope and injected macroaggregates of human albumin tagged with another isotope. There was a prominent gradient of V/Q ratios in the vertical direction. In the horizontal plane there were marked gradients of both ventilation and perfusion of similar appearance with maxima in central lung regions, resulting in only small gradients of V/Q ratios.

Anesthesia, Inhalation↗
PubMed1991

Chronic obstructive pulmonary disease and anaesthesia: formation of atelectasis and gas exchange impairment.

Gas exchange impairment and the development of atelectasis during enflurane anaesthesia were studied in 10 patients (mean age 70 yrs) with chronic obstructive pulmonary disease (COPD). Awake, no patient displayed atelectasis as assessed by computed X-ray tomography. The ventilation/perfusion distribution (VA/Q), studied by the multiple inert gas elimination technique, displayed an increased dispersion of VA/Q ratios (the logarithmic standard deviation of the perfusion distribution, mean log Q SD 0.99; upper 95% confidence limit of normal subject: 0.60), and increased perfusion of regions with low VA/Q ratios (0.005 less than VA/Q less than 0.1: 5.4% of cardiac output). Shunt was negligible (mean 0.6%). Computed chest tomography showed significantly larger cross-sectional thoracic areas than previously seen in subjects with healthy lungs (p less than 0.01). No atelectasis was seen in any patient. During anaesthesia there was a further worsening of the VA/Q mismatch with significantly increased log Q SD (1.29, p less than 0.05) but no increase in shunt (mean 1%). Minor atelectatic areas were noted in three patients, the others displayed no atelectasis at all. Chest dimensions were reduced by no more than 3% during anaesthesia, suggesting an unchanged or only minimally affected functional residual capacity. These findings contrast with those seen in patients with healthy lungs in whom atelectasis and shunt regularly develop during anaesthesia.

Aged↗
PubMed1990

The influence of body position and differential ventilation on lung dimensions and atelectasis formation in anaesthetized man.

The effects of body position and anaesthesia with mechanical ventilation on thoracic dimensions and atelectasis formation were studied by means of computerized tomography in 14 patients. Induction of anaesthesia in the supine position reduced the cross-sectional area for both lungs and caused atelectasis formation in dependent lung regions in 4/5 patients. Conventional ventilation with positive end-expiratory pressure (PEEP) increased thoracic dimensions and reduced, but did not eliminate, the atelectatic areas. The vertical diameters of both lungs were smaller in the lateral position as compared to the supine position (16.7 vs 10.4 cm in the left lung and 17.3 vs 12.8 cm in the right lung). The lateral positioning also caused a large reduction of the atelectatic area in the non-dependent lung. Differential ventilation with selective PEEP to the dependent lung eliminated (3/8 patients) or reduced (5/8 patients) dependent lung atelectasis. It can be concluded that lung geometry is altered in the lateral position: the shape of the lung makes the vertical diameter of each lung less in the lateral position, compared to the supine position. The atelectatic areas are mainly located in the dependent lung in the lateral position, and these atelectatic areas could be further reduced by selective PEEP to this lung.

Adult↗
PubMed1990

Ventilation-perfusion relationships and atelectasis formation in the supine and lateral positions during conventional mechanical and differential ventilation.

Patients without respiratory symptoms were studied awake and during general anesthesia with mechanical ventilation prior to elective surgery. Ventilation-perfusion (VA/Q) relationships, gas exchange and atelectasis formation were studied during five different conditions: 1) supine, awake; 2) supine during anesthesia with conventional mechanical ventilation (CV); 3) in the left lateral position during CV; 4) as 3) but with 10 cm of positive end-expiratory pressure (PEEP) and 5) as 3) but using differential ventilation with selective PEEP (DV + SPEEP) to the dependent lung. Atelectatic areas and increases of shunt blood flow and blood flow to regions with low VA/Q ratios appeared after induction of anesthesia and CV. With the patients in the lateral position, further VA/Q mismatch with a fall in PaO2 and increased dead space ventilation was observed. Atelectatic lung areas were still present, although the total atelectatic area was slightly decreased. Some of the effects caused by the lateral position could be counteracted by adding PEEP. Perfusion of regions with low VA/Q ratios and venous admixture were then diminished, while PaO2 was slightly increased; shunt blood flow and dead space ventilation were essentially unchanged. During CV + PEEP, there was a decrease in cardiac output, compared to CV in the lateral position. DV + SPEEP was more effective than CV + PEEP in decreasing shunt flow and increasing PaO2 in the lateral position; in addition to this, cardiac output was not affected.

Adult↗
PubMed1990

Atelectasis causes gas exchange impairment in the anaesthetised horse.

The anatomical basis of gas exchange impairment in the anaesthetised horse was studied by computerised tomography (CT; three shetland ponies) and morphological analysis (one pony and three horses). By means of CT, densities were seen in dependent lung regions early during anaesthesia, both with spontaneous breathing and with mechanical ventilation. The densities remained for some time where they had initially been created when the animal was turned from dorsal to sternal recumbency. Deep insufflation of the lungs reduced the dense area. Gas exchange was impaired roughly in proportion to the dense area. On histological analysis, the densities were atelectatic and congested with blood. Gravimetry showed no more extravascular water per unit lung tissue in the atelectatic than in the 'normal' regions, and the blood content was increased only slightly. It is concluded that the horse develops atelectasis in dependent lung regions early during anaesthesia in dorsal recumbency, and that atelectasis is the most likely explanation for the large shunt and impaired arterial oxygenation regularly seen during anaesthesia.

Anesthesia↗
PubMed1989

Atelectasis and gas exchange impairment during enflurane/nitrous oxide anaesthesia.

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 atelectatic area.

Adult↗
PubMed1989

Pulmonary densities during anaesthesia. An experimental study on lung morphology and gas exchange.

The nature of dense areas in dependent lung regions regularly seen in anaesthetized humans was examined in a sheep model. During anaesthesia with muscle paralysis and mechanical ventilation dense areas in dependent lung regions could be seen by means of computerized tomography (CT). They had the same location and the same attenuation as in anaesthetized humans. Gas exchange impairment tended to increase in proportion to the size of the dense area on the CT scan. Microscopy showed that the densities in the sheep were atelectatic lung regions, with no or little interstitial oedema and only minor vascular congestion. The atelectatic lung tissue was sharply demarcated and the lung tissue in the immediate vicinity was well aerated, or even hyperinflated. Gravimetry showed the same amount of extravascular fluid and blood per unit lung weight in the atelectatic lung and in the aerated lung region. It is concluded that the densities appearing in dependent lung regions during anaesthesia are caused by atelectasis.

Anesthesia↗
PubMed1988

Thoracoabdominal restriction in supine men: CT and lung function measurements.

Thoracoabdominal restriction was brought on by means of a corset, and the subsequent effects on thoracic dimensions and lung tissue were studied by computerized tomography (CT) and by various lung function tests in supine healthy volunteers (mean age 30 yr). Restriction caused reductions in total lung capacity (helium equilibration) from mean 6.84 to 4.80 liters, in functional residual capacity (FRC) from 2.65 to 2.08 liters, and in vital capacity from 5.16 to 3.45 liters. Closing capacity (single-breath N2 washout) fell from 2.42 to 1.88 liters, thus matching the reduction in FRC. The static pressure-lung volume curve was shifted to the right by 1.5 cmH2O at 50% of total lung capacity. However, no change in the slope of the curve was observed. The diaphragm was moved cranially by 1.2 cm, and the thoracic cross-sectional area was reduced by a mean 32 cm2 at a level just above the diaphragm. No changes in the lung tissue were seen on CT scanning. Gas exchange, as assessed by multiple inert gas elimination technique and arterial blood gas analysis, was unaffected by restriction. It is concluded that in supine subjects, thoracoabdominal restriction that reduces FRC by 0.6 liter is not accompanied by atelectasis (normal CT scan). In this respect the result differs from that found in anesthetized supine subjects who show the same fall in FRC and atelectasis in dependent lung regions.

Abdomen↗