The Olfactomedin-4-Defined Human Neutrophil Subsets Differ in Proteomic Profile in Healthy Individuals and Patients with Septic Shock

The specific granule glycoprotein olfactomedin-4 (Olfm4) marks a subset (1-70%) of human neutrophils and the Olfm4-high (Olfm4-H) proportion has been found to correlate with septic shock severity. The aim of this study was to decipher proteomic differences between the subsets in healthy individuals, hypothesizing that Olfm4-H neutrophils have a proteomic profile distinct from that of Olfm4 low (Olfm4-L) neutrophils. We then extended the investigation to septic shock. A novel protocol for the preparation of fixed, antibody-stained, and sorted neutrophils for LC-MS/MS was developed. In healthy individuals, 39 proteins showed increased abundance in Olfm4-H, including the small GTPases Rab3d and Rab11a. In Olfm4-L, 52 proteins including neutrophil defensin alpha 4, CXCR1, Rab3a, and S100-A7 were more abundant. The data suggest differences in important neutrophil proteins that might impact immunological processes. However, in vitro experiments revealed no apparent difference in the ability to control bacteria nor produce oxygen radicals. In subsets isolated from patients with septic shock, 24 proteins including cytochrome b-245 chaperone 1 had significantly higher abundance in Olfm4-H and 30 in Olfm4-L, including Fc receptor proteins. There was no correlation between Olfm4-H proportion and septic shock severity, but plasma Olfm4 concentration was elevated in septic shock. Thus, the Olfm4-H and Olfm4-L neutrophils have different proteomic profiles, but there was no evident functional significance of the differences in septic shock.

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.

Pre-operative simultaneous stereotactic core biopsy and fine-needle aspiration biopsy in the diagnosis of invasive lobular breast carcinoma

Purpose: To determine the diagnostic value of stereotactic core needle biopsy (SCNB) in comparison to stereotactic fine-needle aspiration biopsy (SFNAB) in patients with invasive lobular carcinoma (ILC).

Material and Methods: Twenty-two patients with clinical or mammographic findings suspicious of malignancy underwent surgery where postoperative histopathology showed ILC. Pre-operative attempts of diagnosis were made using SFNAB and SCNB. SFNAB was done with a spinal needle 0.7- or 0.9-mm and SCNB was simultaneously performed with an automated 2.1-mm biopsy gun in all patients.

Results: SFNAB was diagnostic of carcinoma in 9 women, showed “probable carcinoma” in 5 and “atypia” in 3. In the remaining 5 women, SFNAB showed no atypia.

SCNB diagnosed ILC in 20 patients and showed ILC as well as invasive ductal carcinoma (IDC) in 1. Ductal carcinoma in situ was suggested in the remaining patient.

Conclusion: SCNB was superior to SFNAB in diagnosing ILC and did not miss any carcinoma, whereas SFNAB was non-diagnostic in 8 cases. SCNB is thus recommended in patients with suspicion of ILC of the breast.

Contrasting landscape influences on sediment supply and stream restoration priorities in northern Fennoscandia (Sweden and Finland) and coastal British Columbia

Sediment size and supply exert a dominant control on channel structure. We review the role of sediment supply in channel structure, and how regional differences in sediment supply and land use affect stream restoration priorities. We show how stream restoration goals are best understood within a common fluvial geomorphology framework defined by sediment supply, storage, and transport. Land-use impacts in geologically young landscapes with high sediment yields (e.g., coastal British Columbia) typically result in loss of in-stream wood and accelerated sediment inputs from bank erosion, logging roads, hillslopes and gullies. In contrast, northern Sweden and Finland are landscapes with naturally low sediment yields caused by low relief, resistant bedrock, and abundant mainstem lakes that act as sediment traps. Land-use impacts involved extensive channel narrowing, removal of obstructions, and bank armouring with boulders to facilitate timber floating, thereby reducing sediment supply from bank erosion while increasing export through higher channel velocities. These contrasting land-use impacts have pushed stream channels in opposite directions (aggradation versus degradation) within a phase-space defined by sediment transport and supply. Restoration in coastal British Columbia has focused on reducing sediment supply (through bank and hillslope stabilization) and restoring wood inputs. In contrast, restoration in northern Fennoscandia (Sweden and Finland) has focused on channel widening and removal of bank-armouring boulders to increase sediment supply and retention. These contrasting restoration priorities illustrate the consequences of divergent regional land-use impacts on sediment supply, and the utility of planning restoration activities within a mechanistic sediment supply-transport framework.

Stereotactic core needle biopsy in non-palpable breast lesions. What number is needed?

PURPOSE

To investigate whether three stereotactic core needle biopsies (S-CNB) in non-palpable breast lesion are enough for accurate preoperative diagnosis.

MATERIAL AND METHODS

Between September 1994 and December 2000, 523 patients with mammographically detected breast lesions and who proceeded to surgery were preoperatively stereotactically biopsied with an automated 14-gauge biopsy device. Three samples were taken from each lesion irrespective of whether the lesion presented as "microcalcifications only", "microcalcifications and a mass", or a "mass, architectural distorsion, or stellate lesion without microcalcifications". The histopathology was divided into three subgroups: diagnostic, atypia (ranging from atypical cells to probably cancer), and non-diagnostic material.

RESULTS

Post-surgical histopathology diagnosed 454 (87%) malignant tumors and 69 (13%) benign lesions. Three S-CNB correctly diagnosed the malignant tumors in 84% in the subgroup "microcalcifications only". In the category "microcalcifications and a mass", the diagnostic accuracy was 97% and in the subgroup "mass, architectural distorsion, or stellate lesion without microcalcifications" 3 S-CNB resulted in 93% correct diagnostic material. In 19 of the 454 patients (4%) 1, 2 or all 3 preoperative S-CNB showed atypia. In 20 patients (4%), all 3 S-CNB were non-diagnostic. Thirteen of these 20 patients had "microcalcifications only" and 7 had a mass without microcalcifications.

CONCLUSION

Three S-CNB were enough for correct diagnosis in "masses, architectural distorsions, or stellate lesions without microcalcifications" and in "microcalcifications and a mass", but were not sufficient in "microcalcifications only".

Comparison of preoperative simultaneous stereotactic fine needle aspiration biopsy and stereotactic core needle biopsy in ductal carcinoma in situ of the breast

PURPOSE

To compare the preoperative results of stereotactic fine needle aspiration biopsy (S-FNAB) with stereotactic core needle biopsy (S-CNB) performed simultaneously in breast lesions with the postoperative histopathological diagnosis of ductal carcinoma in situ (DCIS) of all histological grades.

MATERIAL AND METHODS

733 consecutive stereotactic biopsies were performed between May 1993 and June 1999. In 72 patients with mammographic findings suspicious of malignancy who were subjected to breast surgery, postoperative histopathology showed DCIS. Preoperatively, S-FNAB and S-CNB had been done simultaneously in all patients, S-FNAB with spinal needle 0.7 or 0.9 mm and S-CNB was performed with an automated 2.1-mm biopsy gun. An average of 3 S-FNABs and 3 S-CNBs were performed in each patient.

RESULTS

In 56 (78%) of the 72 patients S-CNB showed DCIS. In 3 patients (4%) the S-CNB revealed "probable carcinoma", in 7 patients (10%) "atypia" and in 6, the lesions were benign. In 34 (47%) of the 72 women S-FNABs showed carcinoma, not otherwise specified. In 6 cases (8%) the S-FNABs showed "probable carcinoma" and in 12 patients (17%) "atypia"; 8 lesions were benign and 12 not diagnostic.

CONCLUSION

S-CNB was superior to S-FNAB in diagnosing DCIS. Only 6 patients (8%) received a benign or non-diagnostic preoperative diagnosis with S-CNB compared to 20 patients (28%) with S-FNAB. S-CNB was superior to S-FNAB for preoperative diagnosis of DCIS, but S-FNAB could further increase the sensitivity of the biopsy since it diagnosed cancer in 4 cases where S-CNB showed benign material.

Comparison of preoperative simultaneous stereotactic fine needle aspiration biopsy and stereotactic core needle biopsy in ductal carcinoma in situ of the breast

PURPOSE

To compare the preoperative results of stereotactic fine needle aspiration biopsy (S-FNAB) with stereotactic core needle biopsy (S-CNB) performed simultaneously in breast lesions with the postoperative histopathological diagnosis of ductal carcinoma in situ (DCIS) of all histological grades.

MATERIAL AND METHODS

733 consecutive stereotactic biopsies were performed between May 1993 and June 1999. In 72 patients with mammographic findings suspicious of malignancy who were subjected to breast surgery, postoperative histopathology showed DCIS. Preoperatively, S-FNAB and S-CNB had been done simultaneously in all patients, S-FNAB with spinal needle 0.7 or 0.9 mm and S-CNB was performed with an automated 2.1-mm biopsy gun. An average of 3 S-FNABs and 3 S-CNBs were performed in each patient.

RESULTS

In 56 (78%) of the 72 patients S-CNB showed DCIS. In 3 patients (4%) the S-CNB revealed "probable carcinoma", in 7 patients (10%) "atypia" and in 6, the lesions were benign. In 34 (47%) of the 72 women S-FNABs showed carcinoma, not otherwise specified. In 6 cases (8%) the S-FNABs showed "probable carcinoma" and in 12 patients (17%) "atypia"; 8 lesions were benign and 12 not diagnostic.

CONCLUSION

S-CNB was superior to S-FNAB in diagnosing DCIS. Only 6 patients (8%) received a benign or non-diagnostic preoperative diagnosis with S-CNB compared to 20 patients (28%) with S-FNAB. S-CNB was superior to S-FNAB for preoperative diagnosis of DCIS, but S-FNAB could further increase the sensitivity of the biopsy since it diagnosed cancer in 4 cases where S-CNB showed benign material.

Radiological review of incidence breast cancers

OBJECTIVES

To examine the rate of incidence cancers detectable on review of previous screening mammograms using two reviewing methods. To compare the results with a previous study of interval cancers using the same reviewing methods.

SETTING

Almost 50000 women are regularly invited for service screening at Stockholm Söder Hospital. From 1989 to 1993, 119 women were identified with breast cancer detected at screening and the previous round attendance (incidence cancer).

METHODS

Screening mammograms, obtained before detection of the incidence cancers, were reviewed first mixed with other screening images (ratio 1:8) and then non-mixed. Reviewers from the screening unit responsible for the mammograms as well as reviewers from other units interpreted all images by both single and double reading.

RESULTS

The proportion detected on retrospective review varied between 5% and 50% depending on the review method used and the number of reviewers included to classify a case as truly identified. Generally more cancers were detected when non-mixed samples of mammograms were reviewed than when mixed samples were reviewed (mean increase 23%) and when interpreted by double reading compared with single reading (mean increase 14%).

CONCLUSIONS

In an experimental retrospective set up, fewer incidence cancers were identified in mixed than in non-mixed review. Generally more incidence cancers were identified on review (22%) than previously reported for interval cancers (14%), probably reflecting differences in tumour biology and growth. How many women with potentially visible incidence cancers would have benefited from earlier tumour detection still needs to be evaluated.

Pre-operative simultaneous stereotactic core biopsy and fine-needle aspiration biopsy in the diagnosis of invasive lobular breast carcinoma

PURPOSE

To determine the diagnostic value of stereotactic core needle biopsy (SCNB) in comparison to stereotactic fine-needle aspiration biopsy (SFNAB) in patients with invasive lobular carcinoma (ILC).

MATERIAL AND METHODS

Twenty-two patients with clinical or mammographic findings suspicious of malignancy underwent surgery where postoperative histopathology showed ILC. Pre-operative attempts of diagnosis were made using SFNAB and SCNB. SFNAB was done with a spinal needle 0.7- or 0.9-mm and SCNB was simultaneously performed with an automated 2.1-mm biopsy gun in all patients.

RESULTS

SFNAB was diagnostic of carcinoma in 9 women, showed "probable carcinoma" in 5 and "atypia" in 3. In the remaining 5 women, SFNAB showed no atypia. SCNB diagnosed ILC in 20 patients and showed ILC as well as invasive ductal carcinoma (IDC) in 1. Ductal carcinoma in situ was suggested in the remaining patient.

CONCLUSION

SCNB was superior to SFNAB in diagnosing ILC and did not miss any carcinoma, whereas SFNAB was non-diagnostic in 8 cases. SCNB is thus recommended in patients with suspicion of ILC of the breast.

Two models for radiological reviewing of interval cancers

OBJECTIVES

To compare two different review methods of examining how many of our interval cancers could be regarded as missed cases (overlooked and misinterpreted owing to observer's error).

SETTING

A mass screening programme in Stockholm 1989-91, performed at five independent screening units. 107,846 women attended for screening (70.6% of those invited), and 207 women with interval breast cancers were identified. Interval cancers from two of the units, 104 cases, are reviewed in this study.

METHODS

Screening examinations preceding the interval cancer diagnoses were reviewed both mixed with other screening images in a ratio 1:8 and non-mixed. Both internal reviewers (from the two units responsible for the screening mammograms) and external reviewers (from the other units) took part in the study.

RESULTS

The proportion regarded as missed cases varied between 7% and 34%, depending on what review method was used, and on the number of reviewers included to identify a case as missed. Mixed reviewing reduced the number identified as missed cases by 50% compared with non-mixed reviewing. Whether the reviewer was internal or external made no difference to the results.

CONCLUSIONS

Comparing the rate of missed cases from different studies may be misleading unless the same review method is used. No difference in detection rate could be shown whether the radiologist reviewed images from his/her own screening unit or not. Most of our interval cancers were not regarded as missed cases by either of the two methods.

Occurrence of Gasterophilus intestinalis and some parasitic nematodes of horses in Sweden

A survey was performed on the occurrence of some internal parasites in 461 horses (1-30 years old) slaughtered from October 1992 to September 1993 at the Linköping abattoir in central Sweden. Macroscopical examination was carried out specifically for parasites of the tear ducts and conjunctival sacs of the eyes, and of selected parts of the alimentary tract and cardio-vascular system. The following parasites were found in selected parts of the large intestine: encapsulated cyathostome larvae (in 35.6% of the horses), and mature strongyle worms (17.4%); in the stomach: Gasterophilus intestinalis (12.3% during October-June) and Habronema muscae (1.1%); and in the conjunctival sac: Thelazia lacrymalis (3.1%). Significantly more encapsulated cyathostome larvae were found during January to June than during other times of the year, and horses aged 1-5 years harboured significantly more larvae than older horses. Severe damage to the cranial mesenteric artery and its main branches was noticed in 16 (6.1%) out of 263 horses specifically examined. However, the 4th stage larva of Strongylus vulgaris was only recovered in 6 (2.3%) of the horses. Quantitative and qualitative faecal egg counts were done on 412 and 384 of the horses, respectively. Eggs of strongyles, Parascaris equorum and Strongyloides westeri were found in 78.1%, 1.9% and 0.2% of the faecal samples, respectively. Highest prevalence of strongyle eggs was found during July to September. Third stage larvae of the following nematodes were recovered from faecal cultures: subfamily Cyathostomum sensu lato (78.1%) Triodontophorus spp. (6.5%), Strongylus vulgaris (3.6%), Trichostrongylus axei (1.3%), while Gyalocephalus sp., Oesophagodontus sp., Poteriostomum sp. and Strongylus edentatus each comprised less than 0.5%.

Occurrence of Gasterophilus intestinalis and some parasitic nematodes of horses in Sweden

A survey was performed on the occurrence of some internal parasites in 461 horses (1-30 years old) slaughtered from October 1992 to September 1993 at the Linköping abattoir in central Sweden. Macroscopical examination was carried out specifically for parasites of the tear ducts and conjunctival sacs of the eyes, and of selected parts of the alimentary tract and cardio-vascular system. The following parasites were found in selected parts of the large intestine: encapsulated cyathostome larvae (in 35.6% of the horses), and mature strongyle worms (17.4%); in the stomach: Gasterophilus intestinalis (12.3% during October-June) and Habronema muscae (1.1%); and in the conjunctival sac: Thelazia lacrymalis (3.1%). Significantly more encapsulated cyathostome larvae were found during January to June than during other times of the year, and horses aged 1-5 years harboured significantly more larvae than older horses. Severe damage to the cranial mesenteric artery and its main branches was noticed in 16 (6.1%) out of 263 horses specifically examined. However, the 4th stage larva of Strongylus vulgaris was only recovered in 6 (2.3%) of the horses. Quantitative and qualitative faecal egg counts were done on 412 and 384 of the horses, respectively. Eggs of strongyles, Parascaris equorum and Strongyloides westeri were found in 78.1%, 1.9% and 0.2% of the faecal samples, respectively. Highest prevalence of strongyle eggs was found during July to September. Third stage larvae of the following nematodes were recovered from faecal cultures: subfamily Cyathostomum sensu lato (78.1%) Triodontophorus spp. (6.5%), Strongylus vulgaris (3.6%), Trichostrongylus axei (1.3%), while Gyalocephalus sp., Oesophagodontus sp., Poteriostomum sp. and Strongylus edentatus each comprised less than 0.5%.

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.

Anoplocephala perfoliata in horses in Sweden: prevalence, infection levels and intestinal lesions

Distal ileum, caecum and proximal colon of 470 horses were examined for helminths during 1 year at an abattoir in central Sweden. The infection levels of the horse tapeworm Anoplocephala perfoliata, their stage of development, site of attachment and gross pathological lesions caused by the worm were recorded. Faecal samples from 395 of the horses were examined specifically for tapeworm segments and eggs in order to correlate these findings with the numbers in the alimentary canal. In total 65% of the horses were infected with A. perfoliata and the mean intensity of infection was 79 worms per infected horse with a maximum of 912. The level of infection was significantly higher in (1) 3rd and 4th than in 1st and 2nd quarter of the year; (2) older horses than in yearlings; (3) females than in males and geldings; (4) thoroughbred and cold-blooded horses than in Swedish standard breeds and ponies. The level of infection was unaffected by the usage of anthelminthics against nematodes. Of the horses examined 51% had 1-100 worms whereas 14% were infected with more than 100 worms. Of the tapeworm positive horses 72% had mixed infections with both adult and juvenile worms, 20% solely juveniles, and 8% solely adults. The severity of intestinal lesions exacerbated by increasing numbers of A. perfoliata. About 11% of the intestines examined had severe lesions, but there was no history of acute abdominal distress in any of the horses included in this study. Although the number of detectable eggs was significantly higher for horses heavily infected with A. perfoliata, the egg recovery among infected horses was only 35%. An additional field survey comprising 218 horses on 88 premises in central and southern parts of Sweden showed that the prevalence of A. perfoliata egg positive horses was the same as found on faecal examination during the abattoir survey.

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.

Anoplocephala perfoliata in horses in Sweden: prevalence, infection levels and intestinal lesions

Distal ileum, caecum and proximal colon of 470 horses were examined for helminths during 1 year at an abattoir in central Sweden. The infection levels of the horse tapeworm Anoplocephala perfoliata, their stage of development, site of attachment and gross pathological lesions caused by the worm were recorded. Faecal samples from 395 of the horses were examined specifically for tapeworm segments and eggs in order to correlate these findings with the numbers in the alimentary canal. In total 65% of the horses were infected with A. perfoliata and the mean intensity of infection was 79 worms per infected horse with a maximum of 912. The level of infection was significantly higher in (1) 3rd and 4th than in 1st and 2nd quarter of the year; (2) older horses than in yearlings; (3) females than in males and geldings; (4) thoroughbred and cold-blooded horses than in Swedish standard breeds and ponies. The level of infection was unaffected by the usage of anthelminthics against nematodes. Of the horses examined 51% had 1-100 worms whereas 14% were infected with more than 100 worms. Of the tapeworm positive horses 72% had mixed infections with both adult and juvenile worms, 20% solely juveniles, and 8% solely adults. The severity of intestinal lesions exacerbated by increasing numbers of A. perfoliata. About 11% of the intestines examined had severe lesions, but there was no history of acute abdominal distress in any of the horses included in this study. Although the number of detectable eggs was significantly higher for horses heavily infected with A. perfoliata, the egg recovery among infected horses was only 35%. An additional field survey comprising 218 horses on 88 premises in central and southern parts of Sweden showed that the prevalence of A. perfoliata egg positive horses was the same as found on faecal examination during the abattoir survey.

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.

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)

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.

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.

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.

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.

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.

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.

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.

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.

Barbiturate anaesthesia does not cause pulmonary densities in dogs: a study using computerized axial tomography

The occurrence of roentgenological densities in dependent lung regions was studied in 28 mongrel dogs (mean weight 18.7 kg) during barbiturate anaesthesia and mechanical ventilation. The densities were analysed by means of computerized tomography, permitting transaxial projections of the thorax. Two dogs showed small densities in dependent lung regions, corresponding to 1% of the total intrathoracic area. In five dogs there were small areas of probably increased density, without sharp delineation, in dependent regions. The remaining 21 dogs (75%) exhibited no densities. The frequency of such densities was thus much lower than has been found in anaesthetized human subjects. Moreover, the densities were relatively smaller than those in man and qualitatively different. It is concluded that the development of dependent lung densities differs both quantitatively and qualitatively between dogs and human subjects.

Cardiac function and central haemodynamics in severe chronic obstructive lung disease. Acute and long-term effects of felodipine

Eleven patients, with advanced chronic obstructive lung disease (COLD), received an infusion of the calcium antagonist felodipine at a rate of 0.9 mg/h. Pulmonary and systemic vascular resistances (PVR and SVR) at rest were reduced by 18% (p less than 0.05) and 33% (p less than 0.001), respectively. Cardiac output increased by 33%. The right ventricular and left ventricular ejection fractions (RVEF and LVEF), measured by equilibrium gated radionuclide ventriculography, increased by 32% (p less than 0.01) and 25% (p less than 0.01), respectively. During exercise both PVR and SVR fell by a mean of 30% (p less than 0.01). RVEF and LVEF both increased by about 14% (p less than 0.05 and p less than 0.01). After three months of oral felodipine treatment, a dose-related decrease in PVR was noted at rest (r = -0.83) compared with pretreatment values. There was an increase in RVEF which correlated to a reduction in PVR (r = -0.76). Three patients discontinued the trial due to side effects. It is concluded that the reduction of PVR induced by felodipine is accompanied by an improvement in right heart function as measured by ejection fraction measurements.

Cardiac function and central haemodynamics in severe chronic obstructive lung disease. Acute and long-term effects of felodipine

Eleven patients, with advanced chronic obstructive lung disease (COLD), received an infusion of the calcium antagonist felodipine at a rate of 0.9 mg/h. Pulmonary and systemic vascular resistances (PVR and SVR) at rest were reduced by 18% (p less than 0.05) and 33% (p less than 0.001), respectively. Cardiac output increased by 33%. The right ventricular and left ventricular ejection fractions (RVEF and LVEF), measured by equilibrium gated radionuclide ventriculography, increased by 32% (p less than 0.01) and 25% (p less than 0.01), respectively. During exercise both PVR and SVR fell by a mean of 30% (p less than 0.01). RVEF and LVEF both increased by about 14% (p less than 0.05 and p less than 0.01). After three months of oral felodipine treatment, a dose-related decrease in PVR was noted at rest (r = -0.83) compared with pretreatment values. There was an increase in RVEF which correlated to a reduction in PVR (r = -0.76). Three patients discontinued the trial due to side effects. It is concluded that the reduction of PVR induced by felodipine is accompanied by an improvement in right heart function as measured by ejection fraction measurements.

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.

Computerized tomography of the chest and gas exchange measurements during ketamine anaesthesia

The effects of atelectasis on pulmonary gas exchange were studied in eight supine, clinically lung-healthy patients. Atelectasis was studied by computerized tomography (CT), and gas exchange by blood gas analysis. The distribution of ventilation/perfusion ratios was assessed by a multiple inert gas elimination technique. No patient had any signs of atelectasis in the awake state, and gas exchange was normal. During ketamine anaesthesia and spontaneous breathing, lung ventilation and perfusion were well matched in most subjects. In one patient there was perfusion of poorly ventilated regions amounting to 14% of cardiac output, and in another there was a shunt of 4% of cardiac output; this patient was the only one who developed atelectasis in dependent lung regions. After muscular relaxation and commencement of mechanical ventilation, all patients but one developed both shunt (2-6% of cardiac output) and atelectasis. The shunt correlated to the size of atelectasis. It is concluded that the occurrence of shunt during anaesthesia is related to the development of atelectasis in dependent lung region, which is consistent with the hypothesis that it is changes in chest-wall mechanics that cause atelectasis.

In vivo evaluation of striatal dopamine reuptake sites using 11C-nomifensine and positron emission tomography

In vitro nomifensine demonstrates high affinity and specificity for dopamine reuptake sites in the brain. In the present study 11C-nomifensine was administered i.v. in trace amounts (10-50 micrograms) to ketamine anaesthetized Rhesus monkeys (6-10 kg b.w.) and the time-course of radioactivity within different brain regions was measured by positron emission tomography (PET). Six base-line experiments lasting for 60-80 min were performed. The procedure was repeated after pretreatment with nomifensine (2-6 mg/kg i.v.), another reuptake inhibitor, mazindol (0.3 mg/kg i.v.), desipramine (0.5 mg/kg i.v) or spiperone (0.3 mg/kg i.v.) before the administration of a second 11C-nomifensine dose. The highest radioactivity uptake was found in the dopamine innervated striatum and the lowest in a region containing the cerebellum, known to be almost devoid of dopaminergic neurons. The difference between striatal and cerebellar uptake of 11C-nomifensine derived radioactivity was markedly reduced after nomifensine and mazindol but not after desipramine and spiperone. These results indicate that in vivo the striatal uptake of 11C-nomifensine, as measured with PET, involves specific binding with the dopamine reuptake sites. In the first human applications of 11C-nomifensine and PET in a healthy volunteer, the regional uptake of radioactivity was similar to that in base-line experiments with Rhesus monkeys. In the healthy subject the striatal/cerebellar ratio was 1.6, 50 min after the injection of 11C-nomifensine. In a hemi-parkinsonian patient this ratio was 1.1 contralaterally and 1.3 ipsilaterally to the affected side. 11C-nomifensine and PET seems to be an auspicious method to measure the striatal dopaminergic nerve terminals of man in vivo.

Lung collapse and gas exchange during general anesthesia: effects of spontaneous breathing, muscle paralysis, and positive end-expiratory pressure

Lung densities (atelectasis) and pulmonary gas exchange were studied in 13 supine patients with no apparent lung disease, the former by transverse computerized tomography (CT) and the latter by a multiple inert gas elimination technique for assessment of the distribution of ventilation/perfusion ratios. In the awake state no patient had clear signs of atelectasis on the CT scan. Lung ventilation and perfusion were well matched in most of the patients. Three patients had shunts corresponding to 2-5% of cardiac output, and in one patient there was low perfusion of poorly ventilated regions. CT scans after 15 min of halothane anesthesia and mechanical ventilation showed densities in dependent lung regions in 11 patients. A shunt was present in all patients, ranging from 1% in two patients (unchanged from the awake state) to 17%. Ventilation of poorly perfused regions was noted in nine patients, ranging from 1-19% of total ventilation. The magnitude of the shunt significantly correlated to the size of dependent densities (r = 0.84, P less than 0.001). Five patients studied during spontaneous breathing under anesthesia displayed both densities in dependent regions and a shunt, although of fairly small magnitude (1.8% and 3.7%, respectively). Both the density area and the shunt increased after muscle paralysis. PEEP reduced the density area in all patients but did not consistently alter the shunt. It is concluded that the development of atelectasis in dependent lung regions is a major cause of gas exchange impairment during halothane anesthesia, during both spontaneous breathing and mechanical ventilation, and that PEEP diminishes the atelectasis, but not necessarily the shunt.

Dopamine receptor properties in Parkinson's disease and Huntington's chorea evaluated by positron emission tomography using 11C-N-methyl-spiperone

Dopaminergic receptor properties in the striatum of patients with Parkinson's disease (PD) and Huntington's chorea (HD) were studied by positron emission tomography (PET), using 11C-N-methyl-spiperone as a dopamine D2 receptor ligand. The time-dependent regional radioactive uptake in the caudate nucleus and the putamen was measured and fitted to a 3-compartment pharmacokinetic model. The rate constant k3 for specific binding to the receptor compartment in the striatum was determined in relation to the binding in regions with a low density of specific binding sites, such as the cerebellum and the frontal cortex . k3, which is a measure of the receptor density, was reduced in one patient with HD but less affected in PD in comparison with healthy controls. The pattern of k3 values calculated from the 6 PD patients is discussed in relation to any side-to-side differences in dopamine receptor densities in hemiparkinsonism and to possible "hypersensitivity" of dopamine receptors in the early stage of the disease and down-regulation in more advanced disease.

Constitutional factors promoting development of atelectasis during anaesthesia

The extent of atelectasis was correlated to constitutional factors in 38 patients who underwent computed tomography prior to and during general anaesthesia with halothane. All patients but two developed atelectasis in dependent regions of both lungs immediately after induction of anaesthesia prior to surgery. The transverse area of the densities ranged from 0 to 27 cm2, and there were no significant differences between patients of different age or sex, or with different smoking habits. A significant linear regression was found between Broca's index weight (kg)/height (cm)-100 and the area of the densities, and also between an index describing the shape of the thorax and the density area. Thus, patients who were overweight and/or had a low and wide thorax tended to develop more extensive atelectasis during anaesthesia. This finding might partly explain why overweight patients develop postoperative pulmonary complications more often than non-obese patients.

Densities in dependent lung regions during anaesthesia: atelectasis or fluid accumulation?

In previous studied with computed tomography (CT) prior to and during general anaesthesia, we found that densities developed in dependent parts of the lungs immediately after induction of anaesthesia in all examined patients. It was suggested that the densities were atelectases created by compression of lung tissue but an alternative explanation could be accumulation of extravascular fluid in the lung tissue and/or in the pleural space. In the present study the nature of the densities was analysed in further detail. Injections of contrast medium into the pleural space revealed that the densities were located in the lung tissue and not in the pleural space. By injecting contrast medium intravenously and repeating the CT scanning over a 2-min period the passage of contrast through the major vessels and the lung densities could be studied. The transit time of the contrast medium was of the same magnitude in the densities and the major lung vessels. This indicates that there were no regions with an increased amount of extravascular fluid to delay the contrast passage. These findings oppose the idea of fluid accumulation as the cause of the densities, while atelectasis remains the most plausible explanation.

Correlation of gas exchange impairment to development of atelectasis during anaesthesia and muscle paralysis

Pulmonary gas exchange and the development of atelectasis were studied in eight essentially lung-healthy patients, awake and during halothane anaesthesia with mechanical ventilation. Gas exchange was evaluated by a multiple inert-gas elimination technique and conventional blood-gas analysis, and atelectasis was studied by computerized tomography (CT). Ventilation and lung perfusion were well matched in the majority of the patients when awake. In two patients there was low perfusion of poorly ventilated regions (low VA/Q). One patient had a shunt corresponding to 4% of cardiac output. None of the patients showed signs of atelectasis on the CT scans. After 15 min of anaesthesia, shunt had appeared in all patients, ranging from 1% in two patients (unchanged from the awake state) to 17%. The major VA/Q mode was widened and ventilation of poorly perfused regions (high VA/Q) was noted in seven patients. Densities in dependent lung regions (interpreted as atelectasis) were seen on the CT scans in six patients. The extent of atelectasis was significantly correlated both to the magnitude of shunt (r = 0.93, P less than 0.01) and to the impairment of arterial oxygenation (r = 0.99, P less than 0.001). The findings indicate that atelectasis in dependent lung regions during halothane anaesthesia creates shunting of blood flow and that atelectasis is the major or sole cause of impaired gas exchange in the lung-healthy, anaesthetized subject.

Atelectasis during anaesthesia and in the postoperative period

Transverse sections of lung tissue were studied in patients by computerized tomography during anaesthesia and in the postoperative period. Eight patients were studied during intravenous (thiopentone) and six during inhalational (halothane) anaesthesia. The latter patients were studied during both spontaneous and mechanical ventilation. Five of the patients who underwent surgery for inguinal hernia and five patients in whom laparotomy was performed were studied 1 h and 24 h postoperatively. No patient showed any lung changes while awake preoperatively, and all patients developed dependent, crest-shaped lung densities within 5-10 min of anaesthesia. The densities comprised 3.4% of the lung volume in the caudal (basal) 5 cm of the lung tissue. No significant differences in the size and distribution of the densities were noted between spontaneous breathing and mechanical ventilation during anaesthesia, or between intravenous and inhalational anaesthesia. The densities remained in nine of ten patients 1 h postoperatively, and they remained in five of ten patients 24 h after anaesthesia. The densities are considered to be compression atelectases which may develop as a result of relaxation of the diaphragm. They may be important contributors to postoperative pulmonary complications.

What causes the lowered FRC during anaesthesia?

Functional residual capacity (FRC) by means of body plethysmography chest-abdomen dimensions by whole body computerized tomography, central blood volume (CBV) by double-indicator dilution technique and extremity (peripheral) blood volume (PBV) by segmental thigh and upper arm plethysmography, were assessed in lung-healthy patients who were to undergo general anaesthesia and elective surgery. Anaesthesia was induced by thiopentone and was maintained either by a continuous drip of thiopentone or by inhalation of halothane. Muscle relaxation was obtained by pancuronium bromide. Anaesthesia caused a reduction of the total thoracic volume by an average of 0.75 1. This followed from a cranial shift of the diaphragm and to less extent by a reduced transversal chest area. FRC was concomitantly reduced by an average of 0.5 1 and the CBV, mainly thoracic blood, was reduced by 0.25 - 0.3 1. PBV was slightly reduced by 0.1 1, and it is concluded that these fractions of CBV and TBV must have been pooled in the abdomen. This pooling resulted in more or less maintained transversal abdomen area despite the cranial shift of the diaphragm.

New aspects on atelectasis during anaesthesia

Sixteen subjects were studied with regard to lung tissue changes during general anaesthesia. The transverse area and the structure of the lung tissue were studied by computerized tomography. No abnormalities were noted in the lung tissue before anaesthesia, but within five minutes after induction, all subjects had developed crest-shaped dependent changes of an increased density in both lungs. They correspond to 4 - 5 per cent of the total transverse area. The size of the densities could not be correlated to the age of the subjects, or time of the anaesthesia, and they were not affected by the inspiratory oxygen fraction. They could be rotated by turning the patient, and the application of a positive end-expiratory pressure eliminated or reduced the densities. It is suggested that the densities are atelectases, which develop by compression of lung tissue, and not by gas resorption.

Pulmonary densities during anesthesia with muscular relaxation--a proposal of atelectasis

Twenty patients (23-76 yr) were studied with regard to lung tissue changes prior to and following induction of general anesthesia with muscular relaxation, and another four subjects were studied for a longer period awake. The transverse thoracic area and the structure of the lung tissue were determined by computerized tomography. No abnormalities in the lung tissue were noted before anesthesia. Within 5 min after induction, including muscular relaxation, all subjects had developed crest-shaped changes of increased density in the dependent regions of both lungs. They were largest in the most caudal segment (4.8 +/- 0.8% of the transverse lung area, mean +/- SE) and smaller in the cephalad exposures (3.4 +/- 0.7% of the transverse area). The size of the densities showed no correlation to age. The densities did not increase after a further 20 min of anesthesia and were not affected by the inspiratory oxygen fraction. When the subjects were moved from the supine to the lateral position, the crest-shaped densities disappeared in the nondependent lung and remained in the dorsal part of the dependent lung. The application of positive end-expiratory pressure of 10 cmH2O eliminated or reduced the densities. The four awake subjects showed no lung densities after 90 min in the supine position. It is suggested that these crest-shaped densities represent atelectases, which develop by compression of lung tissue rather than by resorption of gas.

Functional residual capacity, thoracoabdominal dimensions, and central blood volume during general anesthesia with muscle paralysis and mechanical ventilation

Functional residual capacity (FRC), rib cage and abdominal dimensions (rc-ab), central blood volume (CBV), and extra vascular lung water (EVLW) were measured in six lung-healthy subjects awake and during halothane anesthesia, muscle paralysis, and mechanical ventilation. FRC was assessed by multiple breath nitrogen washout, rc-ab dimensions by computerized tomography, and CBV and EVLW by a double-indicator dilution technique (thermo-dye). During anesthesia, FRC decreased by 0.5 1 (17%). The cross-sectional chest area was reduced by 12-20 cm2, causing an approximate reduction in thoracic volume by 0.3 1. Concomitantly, the diaphragm was moved cranially by an average of 1.9 cm, diminishing the thoracic volume a further 0.5 1. The abdominal cross-sectional area did not alter significantly, despite the shift of the diaphragm. CBV decreased by 0.3 1. EVLW did not change significantly. It is concluded that the thoracic volume is reduced during halothane anesthesia, muscle paralysis, and mechanical ventilation as a result of cranial shift of the diaphragm and reduction in transverse area. The decrease in thoracic volume is accompanied by a reduction in FRC and a displacement of blood from the thorax to the abdomen, the transverse area of the latter thus being maintained despite the shift of the diaphragm.

Parafilaria bovicola (Tubangui 1934) established in Swedish cattle

Parafilaria bovicola was recorded in Swedish cattle for the first time in 1978. The parasite causes carcass lesions with a maximum incidence from February to July but already in the previous November the carcass lesions appear regularly in the form of yellow oedema. In February and onward the oedema may be extensive with a greenish-yellow colour. The lesions are most prominent in bulls and more or less negligible in cows. However, the cows are considered to be important reservoirs for the parasite from one season to the next. Bleedings are seen from March until August and the infective larvae are transmitted to the cattle from early June by the intermediate host Musca autumnalis. Parafilaria lesions look remarkably like those caused by contusions during handling and transport previous to slaughter. Eosinophile infiltrations can be regarded as a constant diagnostic feature of parafilariosis.

Parafilaria bovicola (Tubangui 1934) in cattle: epizootiology-disease occurrence

Parafilaria bovicola, a filariid nematode affecting cattle, was first identified in Sweden in 1978. The parasite (female, 5 to 6 cm long, 500 micrometer wide; male, half that size) is associated with lesions caused when the worm is moving subcutaneously and IM, giving rise to condemnation losses of approximately 6 kg of meat in an affected animal at slaughter. Several hypotheses were tested in a questionnaire survey among cattle owners in he enzootic area of the disease, attempting to investigate factors associated with its occurrence in Sweden (i) Condemnation losses due to P bovicola were overrepresented among animals that came from herds held on pasture the previous year, as opposed to animals from farms with indoor cattle management only, indicating that infection of cattle occurs while they are on pasture. (ii) A statistically significant difference was found between affected and nonaffected herds with respect to age groups, with most cattle affected belonging to the 1- to 2-year age group. And (iii), frequency of Parafilaria-induced lesions showed a seasonal trend, increasing sharply in late December, remaining at about 30% of the slaughter population until July, at which time it dropped to insignificant levels. Seemingly delaying the time of slaughter of animals until the 2nd half of the year may ensure time for lesions to heal and lessen economic losses due to condemnations.