Regulatory T-Cell Phenotyping Using CyTOF

Regulatory T cells are an important component of the immune system that plays a key role in maintaining homeostasis. Identification of distinct regulatory T cell subsets is essential to understand their function. Mass cytometry or CyTOF is a technology that enables the simultaneous measurement of up to 50 markers in single cells by using antibodies tagged with heavy metals, which are then detected with time-of-flight mass spectrometry. This chapter describes a mass cytometry approach for phenotypic characterization of regulatory T cells and determination of their master transcription factor Foxp3.

Pregnancy induces pancreatic insulin secretion in women with long-standing type 1 diabetes

INTRODUCTION

Pregnancy entails both pancreatic adaptations with increasing β-cell mass and immunological alterations in healthy women. In this study, we have examined the effects of pregnancy on β-cell function and immunological processes in long-standing type 1 diabetes (L-T1D).

RESEARCH DESIGN AND METHODS

Fasting and stimulated C-peptide were measured after an oral glucose tolerance test in pregnant women with L-T1D (n=17) during the first trimester, third trimester, and 5-8 weeks post partum. Two 92-plex Olink panels were used to measure proteins in plasma. Non-pregnant women with L-T1D (n=30) were included for comparison.

RESULTS

Fasting C-peptide was detected to a higher degree in women with L-T1D during gestation and after parturition (first trimester: 64.7%, third trimester: 76.5%, and post partum: 64.7% vs 26.7% in non-pregnant women). Also, total insulin secretion and peak C-peptide increased during pregnancy. The plasma protein levels in pregnant women with L-T1D was dynamic, but few analytes were functionally related. Specifically, peripheral levels of prolactin (PRL), prokineticin (PROK)-1, and glucagon (GCG) were elevated during gestation whereas levels of proteins related to leukocyte migration (CCL11), T cell activation (CD28), and antigen presentation (such as CD83) were reduced.

CONCLUSIONS

In summary, we have found that some C-peptide secretion, that is, an indirect measurement of endogenous insulin production, is regained in women with L-T1D during pregnancy, which might be attributed to elevated peripheral levels of PRL, PROK-1, or GCG.

Co-designing an online support program for and with informal carers of people with heart failure

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swedish research council for health, working life and welfare

Background

Informal care is increasing due to societal challenges such as ageing populations, more non-communicable diseases in combination with lack of health care personnel. Informal carers, namely family members, friends and neighbours, are important actors in the care and support of people with heart failure. To support them in their caring, information and communication technology has shown to be promising. The mentioned challenges have also put pressure on digitalising health care. The COVID 19 pandemic has further highlighted the need to provide and receive support through digital services. There is currently a lack of support interventions for carers of people with heart failure that are directly integrated within the health care system. To develop relevant support carers should be involved in the process.

Purpose

The aim of the study was to describe the co-design process in the development of an online support program for carers of people with heart failure.

Methods

Informal carers, researchers and practitioners were involved in the co-design process. In the first phase an assessment of carers’ needs and preferences was performed based on a literature search, focus group interviews (n=23 carers), individual interviews and user group sessions (n= 7 carers). Phase two continued with the actual development of the support program prototype, based on the results of phase one. This phase included 13 carers and 18 researchers and practitioners. In the final phase, the program was reviewed and refined by carers, practitioners, and researchers. The project group coordinated the co-design process and took part in the development of the support program.

Results

The co-design process resulted in an online support program consisting of 15 modules with the aim to increase carers’ preparedness to care for a person with heart failure. Each module focused on different topics such as "About heart failure" and "To be a carer". The support program was designed and integrated within the Swedish national e-health platform "1177" in a section called "support and treatment". During the co-design process, various challenges arose, which included the choice of platform itself which then influenced the further co-design process. This process involved balancing implementation and sustainability requirements, against carers’ needs and preferences regarding the program itself.

Conclusions

To conduct a co-design process involving carers and other actors means to navigate diverse interests, goals and pay due attention to regulations. It is an explorative process in which researchers need to be flexible. The effects of the program will now be tested via a randomized controlled trial, and the results will also illuminate the co-design process further.

Increased Plasma Levels of the Co-stimulatory Proteins CDCP1 and SLAMF1 in Patients With Autoimmune Endocrine Diseases

Despite that autoimmune diseases share similar immunogenetic mechanisms, studies comparing the protein composition in peripheral blood from patients with autoimmune endocrine diseases are limited. In this study, we applied proximity extension assay to measure proteins related to signaling and interactions within the immune system in peripheral blood from patients with new-onset (N-T1D) and long-standing (L-T1D) type 1 diabetes, Hashimoto's thyroiditis (HT), Graves' disease (GD), and autoimmune Addison's disease in addition to healthy controls (HC). Proteins in plasma and supernatants from cultured PBMC were measured by using a 92-plex Olink® INFLAMMATION panel. Soluble CDCP1 was more abundant in plasma from patients with N-T1D, L-T1D, HT, and GD than in HC. The L-T1D and HT groups had elevated plasma levels of SLAMF1 compared with HC. Patients and HC could not be distinguished by their protein composition in PBMC supernatants. The high-throughput multiplex technology enabled us to detect two low-abundant proteins that have been gradually connected to autoimmune diseases. Our study provides novel associations between CDCP1, SLAMF1, and autoimmune endocrine diseases, which might reflect a higher degree of inflammation and lymphocyte activation.

Mass Cytometry Studies of Patients With Autoimmune Endocrine Diseases Reveal Distinct Disease-Specific Alterations in Immune Cell Subsets

Although there is evidence that autoimmune diseases share similar immunogenetic mechanisms, studies comparing peripheral CD45⁺ cells from patients with autoimmune endocrine diseases in parallel are limited. In this study, we applied high-dimensional single-cell mass cytometry to phenotypically characterize PBMC from patients with new-onset (N-T1D) and long-standing type 1 diabetes, Hashimoto's thyroiditis (HT), Graves' disease and autoimmune Addison's disease (AD), as well as healthy controls. The frequency of CD20^loCD27^hiCD38^hiHLA-DR^int plasmablasts, CD86⁺CD14^loCD16⁺ non-classical monocytes and two subsets of CD56^dimHLA-DR⁺IFN-γ⁺ NK cells were increased in patients with HT. Subsets of CD56^dimCD69⁺HLA-DR^- NK cells and CD8⁺ TEMRA cells, both expressing IFN-γ, were expanded and reduced, respectively, in the N-T1D group. In addition, patients with AD were characterized by an increased percentage of central memory CD8⁺ T cells that expressed CCR4, GATA3, and IL-2. We demonstrate that patients with N-T1D, HT, and AD had altered frequencies of distinct subsets within antigen-presenting and cytotoxic cell lineages. Previously unreported alterations of specific cell subsets were identified in samples from patients with HT and AD. Our study might contribute to a better understanding of shared and diverging immunological features between autoimmune endocrine diseases.

Mechanisms of K(+) induced renal vasodilation in normo- and hypertensive rats in vivo

AIM

We investigated the mechanisms behind K(+) -induced renal vasodilation in vivo in normotensive Sprague-Dawley (SD) rats and spontaneously hypertensive rats (SHR).

METHODS

Renal blood flow (RBF) was measured utilizing an ultrasonic Doppler flow probe. Renal vascular resistance (RVR) was calculated as the ratio of mean arterial pressure (MAP) and RBF (RVR = MAP/RBF). Test drugs were introduced directly into the renal artery. Inward rectifier K(+) (K(ir) ) channels and Na(+) ,K(+) -ATPase were blocked by Ba(2+) and ouabain (estimated plasma concentrations ∼20 and ∼7 μm) respectively.

RESULTS

Confocal immunofluorescence microscopy demonstrated K(ir) 2.1 channels in pre-glomerular vessels of SD and SHR. Ba(2+) caused a transient (6-13%) increase in baseline RVR in both SD and SHR. Ouabain had a similar effect. Elevated renal plasma [K(+) ] (∼12 mm) caused a small and sustained decrease (5-13%) in RVR in both strains. This decrease was significantly larger in SHR than in SD. The K(+) -induced vasodilation was attenuated by Ba(2+) in control SD and SHR and by ouabain in SD. Nitric oxide (NO) blockade using l-NAME treatment increased MAP and decreased RBF in both rat strains, but did not affect the K(+) -induced renal vasodilation.

CONCLUSION

K(+) -induced renal vasodilation is larger in SHR, mediated by K(ir) channels in SD and SHR, and in addition, by Na(+) ,K(+) -ATPase in SD. In addition, NO is not essential for K(+) -induced renal vasodilation.

Evaluation of the Video Intubation Unit in morbid obese patients

BACKGROUND

Tracheal intubation may be more difficult in morbidly obese (MO) patients than in the non-obese. The aim of this study was to evaluate clinically if the use of the Video Intubation Unit (VIU), a video-optical intubation stylet, could improve the laryngoscopic view compared with the standard Macintosh laryngoscope in this specific population.

METHODS

We studied 40 MO patients (body mass index >35 kg/m(2)) scheduled for bariatric surgery. Each patient had a conventional laryngoscopy and a VIU inspection. The laryngoscopic grades (LG) using the Cormack and Lehane scoring system were noted and compared. Thereafter, the patients were randomised to be intubated with one of the two techniques. In one group, the patients were intubated with the help of the VIU and in the control group, tracheal intubation was performed conventionally. The duration of intubation, as well as the minimal SpO(2) achieved during the procedure, were measured.

RESULTS

Patient characteristics were similar in both groups. Seventeen patients had a direct LG of 2 or 3 (no patient had a grade of 4). Out of these 17 patients, the LG systematically improved with the VIU and always attained grade 1 (P<0.0001). The intubation time was shorter within the VIU group, but did not attain significance. There was no difference in the SpO(2) post-intubation.

CONCLUSION

In MO patients, the use of the VIU significantly improves the visualisation of the larynx, thereby improving the intubation conditions.

Endemic hepatitis E in two Nordic countries

Antibodies against hepatitis E virus (anti-HEV) were found in 248 Swedish and Danish patients between 1993 and 2007. Most patients were symptomatic and tested for anti-HEV due to travel abroad. Among patients with known country of infection, most were infected in Asia, mainly on the Indian subcontinent. However, 29 patients were infected in Europe, nine of these had HEV IgM and/or HEV RNA in serum. In sera from 65 of 141 tested patients HEV RNA could be detected, and 63 strains could be typed by limited sequencing within ORF2. HEV RNA was found in sera from 71% of the patients with HEV IgM and IgG and in 18% of the patients with only detectable HEV IgG. It was also found up to three weeks after the onset of disease in 67% of the patients with known date of onset. Patients infected in Europe were infected by genotype 3, and were older than those infected by genotype 1 (mean age 55.3 vs 30 years, p<0.001). Since it is known that genotype 3 can infect domestic pigs, HEV strains from 18 piglets in 17 herds in Sweden and Denmark were sequenced. Phylogenetic analyses of the genotype 3 strains showed geographical clades and high similarity between strains from patients and pigs from the same area. There are thus autochthonous hepatitis E cases in Scandinavia, and there are probably many undiagnosed ones. Patients with hepatitis of unknown etiology should therefore be investigated for anti-HEV even if they have not been outside Europe, since infections acquired from pigs or other animals should be taken into consideration.

Videolaryngoscopy improves intubation condition in morbidly obese patients

BACKGROUND AND OBJECTIVE

Tracheal intubation may be more difficult in morbidly obese patients (body mass index >35 kg m(-2)) than in the non-obese. Recently, new video-assisted intubation devices have been developed. After some experience with videolaryngoscopy, we hypothesized that it could improve the laryngoscopic view in this specific population and therefore facilitate intubation. The aim of this study was to assess the benefit of a videolaryngoscope on the grade of laryngoscopy in morbid obesity.

METHODS

We studied 80 morbidly obese patients undergoing bariatric surgery. They were randomly assigned to one of two groups. One group was intubated with the help of the videolaryngoscope and in the control group the screen of the videolaryngoscope was hidden to the intubating anaesthesiologist. The primary end-point of the study was to assess in both groups the Cormack and Lehane direct and indirect grades of laryngoscopy. The duration of intubation, the number of attempts needed as well as the minimal SPO2 reached during the intubation process were measured.

RESULTS

Grade of laryngoscopy was significantly lower with the videolaryngoscope compared with the direct vision (P < 0.001). When the grade of laryngoscopy was higher than one with the direct laryngoscopy (n = 30), it was lower in 28 cases with the videolaryngoscope and remained the same only in two cases (P < 0.001). The minimal SPO2 reached during the intubation was higher with the videolaryngoscope but it did not reach statistical significance.

CONCLUSIONS

In morbidly obese patients, the use of the videolaryngoscope significantly improves the visualization of the larynx and thereby facilitates intubation.

Antagonism of neuromuscular blockade but not muscle relaxation affects depth of anaesthesia

BACKGROUND

Conflicting effects of neuromuscular blocking drugs and anticholinesterases on depth of anaesthesia have been reported. Therefore we evaluated the effect of atracurium and neostigmine on bispectral index (BIS) and middle-latency auditory evoked potentials (AAI).

METHODS

We studied 40 patients (ASA I-II) aged 18-69 yr. General anaesthesia consisted of propofol and remifentanil by target-controlled infusion and neuromuscular function was monitored by electromyography. When BIS reached stable values, patients were randomly assigned to one of two groups. Group 1 received atracurium 0.4 mg kg(-1) and, 5 min later, the same volume of NaCl 0.9%; group 2 received saline first and then atracurium. When the first twitch of a train of four reached 10% of control intensity, patients were again randomized: one group (N) received neostigmine 0.04 mg kg(-1) and glycopyrrolate 0.01 mg kg(-1), and the control group (G) received only glycopyrrolate.

RESULTS

Injection of atracurium or NaCl 0.9% had no effect on BIS or AAI. After neostigmine-glycopyrrolate, BIS and AAI increased significantly (mean maximal change of BIS 7.1 [SD 7.5], P<0.001; mean maximal change of AAI 9.7 [10.5], P<0.001). When glycopyrrolate was injected alone BIS and AAI also increased (mean maximal change of BIS 2.2 [3.4], P=0.008; mean maximal change of AAI 3.5 [5.7], P=0.012), but this increase was significantly less than in group N (P=0.012 for BIS; P=0.027 for AAI).

CONCLUSION

These data suggest that neostigmine alters the state of propofol-remifentanil anaesthesia and may enhance recovery.

Fatal myocardial infarction after lung resection in a patient with prophylactic preoperative coronary stenting †

In this report we present the case of a 77-yr-old man who underwent resection of the upper lobe of the left lung for a carcinoma, six weeks after percutaneous transluminal coronary angioplasty (PTCA) with stenting of the left anterior descending (LAD) and circumflex coronary arteries. Antiplatelet therapy with clopidogrel was interrupted two weeks before surgery to allow for epidural catheter placement and to minimize haemorrhage. The surgical procedure was uneventful. In the immediate postoperative period, however, the patient suffered severe myocardial ischaemia. Emergency coronary angiography showed complete thrombotic occlusion of the LAD stent. In spite of successful recanalization, reinfarction occurred and the patient died in cardiogenic shock. Prophylactic preoperative coronary stenting may put the patient at risk of stent thrombosis if surgery cannot be postponed for three months. In such cases, other strategies such as perioperative beta-blockade for preoperative cardiac management should be considered.

The effect of positive airway pressure during pre-oxygenation and induction of anaesthesia upon duration of non-hypoxic apnoea

Positive end-expiratory pressure (PEEP) applied during induction of anaesthesia may prevent atelectasis formation in the lungs. This may increase the duration of non-hypoxic apnoea by increasing the functional residual capacity. We studied the benefit of PEEP applied during the induction of anaesthesia on the duration of apnoea until the SpO2 reached 90%. Forty ASA I-II patients were randomly allocated to one of two groups. In the PEEP group (n = 20) patients were pre-oxygenated using 100% O2 administered using a CPAP device (6 cmH2O) for 5 min. Following induction of anaesthesia, patients were mechanically ventilated (PEEP 6 cm H2O) for a further 5 min. In the ZEEP group (n = 20), no CPAP or PEEP was used. The duration of apnoea until SpO2 reached 90% was measured. Non-hypoxic apnoea duration was longer in the PEEP group compared to ZEEP group (599 +/- 135 s vs. 470 +/- 150 s, p = 0.007). We conclude that the application of positive airway pressure during induction of anaesthesia in adults prolongs the non-hypoxic apnoea duration by > 2 min.

Morbid obesity and postoperative pulmonary atelectasis: an underestimated problem

Perturbation of respiratory mechanics produced by general anesthesia and surgery is more pronounced in morbidly obese (MO) patients. Because general anesthesia induces pulmonary atelectasis in nonobese patients, we hypothesized that atelectasis formation would be particularly significant in MO patients. We investigated the importance and resorption of atelectasis after general anesthesia in MO and nonobese patients. Twenty MO patients were anesthetized for laparoscopic gastroplasty and 10 nonobese patients for laparoscopic cholecystectomy. We assessed pulmonary atelectasis by computed tomography at three different periods: before the induction of general anesthesia, immediately after tracheal extubation, and 24 h later. Already before the induction of anesthesia, MO patients had more atelectasis, expressed in the percentage of the total lung area, than nonobese patients (2.1% versus 1.0%, respectively; P < 0.01). After tracheal extubation, atelectasis had increased in both groups but remained significantly more so in the MO group (7.6% for MO patients versus 2.8% for the nonobese; P < 0.05). Twenty-four hours later, the amount of atelectasis remained unchanged in the MO patients, but we observed a complete resorption in nonobese patients (9.7% versus 1.9%, respectively; P < 0.01). General anesthesia in MO patients generated much more atelectasis than in nonobese patients. Moreover, atelectasis remained unchanged for at least 24 h in MO patients, whereas atelectasis disappeared in the nonobese.

IMPLICATIONS

We compared the resolution over time of pulmonary atelectasis after a laparoscopic procedure by performing computed tomography scans in two different groups of patients: 1 group had 10 nonobese patients, and in the other group there were 20 morbidly obese patients.

Information Centre: responding to needs of older people and carers

This article is the fourth in the series focusing on recent developments in the Elderly West Research Centre in western Sweden. It describes an innovative research, development and evaluation project, the Aldre Vast Information Centre (AV IC), which was developed in direct response to the local needs of Swedish older people and their family carers who participated in the EU ACTION project (Assisting Carers using Telematics Interventions to meet Older persons' Needs) outlined in the first article in this series (Vol 11(11): 759-763). Families requested easier access to information, education and support from professional carers. They also valued the informal support network from other family carers who listened and shared experiences together. In response to these needs, the AV IC project was established to provide telephone, videophone and internet support to older citizens and their families living in the Sjuharad area of west Sweden. The Information Centre is run by professionals and volunteers with the aim of empowering and supporting older people and their families to make informed choices and decisions regarding health and social care matters of importance to them. The project provides an innovative example of how the Aldre Vast Sjuharad user-focused philosophy (Magnusson et al, 2001) can be applied in practice to provide an appropriate evaluation model - namely, one that enables all those stakeholders in the IC to have a voice in its shape and direction.

Supporting family carers through the use of information and communication technology--the EU project ACTION

Assisting Carers Using Telematics Interventions to meet Older persons' Needs (ACTION) is an EU project designed to improve the quality of life of frail older and disabled people and their family carers by the use of information and communication technology. It involved Sweden, England, Northern Ireland, the Republic of Ireland and Portugal. This article provides an overview of the research and development process of the ACTION system and services. The focus is upon the evaluation results with regard to the quality of life of older people and their family carers, the usability of ACTION and cost considerations. Recommendations are made regarding user-focused technology such as ACTION.

Comparison of calculated, measured and self-assessed intelligibility of speech in noise for hearing-aid users

The Speech Intelligibility Index (SII) was used along with paired-comparison judgements and speech recognition scores to compare the speech intelligibility provided by two hearing-aid frequency responses in two different background noises. The purpose was to validate an SII-based procedure. Test subjects were 26 hearing-aid users representing a wide range of hearing loss configurations. One hearing-aid setting was in close agreement with the NAL-R prescription, whereas the other setting was achieved by reducing the high-frequency gain by about 10 dB compared to NAL-R. There were good overall agreements between results of the three methods. Average speech recognition scores were about 4 percentage points higher for the NAL-R frequency response, which also was subjectively judged as significantly better in terms of speech intelligibility. The SII based procedure was found to be suitable for comparing hearing-aid characteristics within subjects.

Comparison of open and arthroscopic stabilization for recurrent shoulder dislocation in patients with a Bankart lesion

We performed a prospective study of 117 patients (119 shoulders) with symptomatic, recurrent anterior posttraumatic shoulder instability to compare open versus arthroscopic reconstruction. Arthroscopic reconstructions (N = 66) were performed using bioabsorbable tacks (Suretac fixators), whereas open reconstructions (N = 53) were performed with suture anchors. All of the patients had a Bankart lesion. Independent observers examined 108 of the 119 shoulders (91%) at a median follow-up period of 28 months (range, 24 to 63) for the arthroscopic group and 36 months (range, 24 to 63) for the open group. The recurrence rate, including both dislocations and subluxations, was 9 of 60 (15%) in the arthroscopic group, compared with 5 of 48 (10%) in the open group. At follow-up, the Rowe score was 93 points (range, 39 to 100) and the Constant score was 91 points (range, 56 to 100) in the arthroscopic group, compared with 89 points (range, 53 to 100 and 57 to 100 for the Rowe and Constant scores, respectively) for both scores in the open group. The only significant difference was in external rotation in abduction, which was 90 degrees (range, 50 degrees to 135 degrees) in the arthroscopic group and 80 degrees (range, 25 degrees to 115 degrees) in the open group. Both methods produced stable and well-functioning shoulders in the majority of patients.

A population based study of Swedish women's opinions about antenatal, delivery and postpartum care

OBJECTIVE

To investigate the views and experiences of Swedish women regarding antenatal, delivery and postpartum care.

STUDY DESIGN

A random sample of women from the birth cohorts 1955, 1959, 1963, 1967 and 1971 resident in the city of Göteborg (n=2880) was invited by letter to complete a questionnaire regarding antenatal, delivery and postpartum care.

RESULTS

The overall response rate was 73% and 1130 (54%) of the 2109 responders had given birth to at least one child. Eighty-one percent of parous women answered that checking blood and urine samples, fetal heart rate, and the measurement of fundal height were the most important procedures in antenatal care. A majority had a positive attitude towards the use of electronic fetal heart rate monitoring (parous 85%; nulliparous 84%). Sixty percent of parous women were aware that ultrasound examination was voluntary and a majority (90%) had a positive attitude towards ultrasound scanning. Forty-three percent of parous women wanted antenatal clinics to be open until 8.00 p.m. A minority of both parous (4%) and nulliparous (4%) women were interested in home delivery. There were more parous (33%) than nulliparous (12%) women who expressed no anxiety at all about the next delivery. Seventy-nine percent of the parous women reported that they would like to have a planned visit with a delivery ward midwife before the next delivery. About 80% reported that they would feel very safe if their partners were present at the delivery (nulliparous 79%; parous 84%). Eighty-five percent preferred a single room or a room together with only one other woman in the postnatal ward. Seventy-two percent of the women wanted to stay 72 hours or less in the postpartum ward and 24% thought there had been too many visitors during the postnatal period. Over 80% were very positive towards breast-feeding. Approximately 80% of all women considered regular contractions up to twelve hours to be acceptable before delivery.

CONCLUSIONS

This study has provided some useful information about women's opinion regarding antenatal, delivery and postpartum care which may be taken into account when instigating changes in the maternity care system.

Predicted and measured speech recognition performance in noise with linear amplification

OBJECTIVE

The purpose of this study was to investigate the applicability of the Speech Intelligibility Index (SII) in hearing aid fitting. It was hypothesized that estimated speech intelligibility, based on the SII, could be a more reliable measure than real speech recognition results for comparing hearing aid characteristics.

DESIGN

The test subjects were 29 elderly persons (66 to 80 yr) with mild-to-moderate hearing loss, who were using monaurally fitted linear hearing aids. They were selected from the files at Sahlgrenska hearing clinic. Speech recognition scores were obtained at fixed speech-to-noise ratios with Phonemically Balanced (PB) words in speech-weighted noise and in low-frequency noise. A Just-Follow-Conversation (JFC) test was performed with connected speech presented in the same background noises. The subjects were tested without hearing aid and with their hearing aids set at three different frequency responses. Predicted speech recognition scores were calculated for each condition based on the SII, complemented with a correction for sensorineural hearing impairment. The calculations involved speech and noise spectra, pure tone thresholds and insertion gain responses.

RESULTS

For each condition, the measured speech recognition scores were, on average, well predicted by the calculated scores. The intra-individual standard deviation of the predicted scores was estimated to be about one percent unit. The group results of the JFC test were in agreement with the word recognition results for the aided conditions, but a floor effect was observed for the unaided conditions.

CONCLUSIONS

Speech intelligibility prediction based on the modified SII is a valid estimate of speech recognition performance of hearing-impaired persons with mild-to-moderate hearing loss. Estimated intelligibility based on the SII is more reliable than actually measured speech recognition performance, for comparing amplification conditions within subjects.

The safety of one, or repeated, vital capacity maneuvers during general anesthesia

A vital capacity maneuver (VCM) (inflating the lungs to 40 cm H(2)O for 15 s) is effective in relieving atelectasis during general anesthesia or after cardiopulmonary bypass (CPB). The study was undertaken to investigate the safety of one or repeated VCM. Five groups of six pigs were studied. Two groups had general anesthesia for 6 h and one group received a VCM every hour. Three other groups received CPB. VCM was performed after CPB in two of these groups. VCM was then repeated every hour in one of the groups. Lung damage was evaluated by extravascular lung water (EVLW) measurement, light microscopy, and the half-time (T(1/2)) of disappearance from the lung of a nebulized aerosol containing (99m)Tc-DTPA. No changes were noted in extravascular lung water. The pigs subjected to VCM decreased their T(1/2). In the groups exposed to repeated VCM, T(1/2) remained lowered (CPB pigs) or decreased over time (non-CPB pigs). No lung damage could be seen on the morphology study. These results suggest that one VCM is a safe procedure. The increase in lung clearance of (99m)Tc-DTPA not associated with an increase in lung water when VCM is repeated may have been caused by an increase in lung volume. Therefore, repeated VCM also appears to be safe.

IMPLICATIONS

This study demonstrates in an animal model that inflating the lung once or repeatedly to the vital capacity is a safe procedure. This maneuver, also called the vital capacity maneuver, can be used to relieve lung collapse which occurs in all patients during general anesthesia.

Hypersensitivity to sound--questionnaire data, audiometry and classification

This study included consecutive case histories and audiometry of 100 patients with hypersensitivity to sounds. There are several different conditions with the symptom of hypersensitivity to sounds. Hyperacusis is one of those and is seldom described in the literature. The term hyperacusis is often used synonymously with hypersensitivity to sound. We propose that there is a specific condition that could be termed hyperacusis. Hyperacusis is often elicited by loud sounds or by a number of other traumata or diseases. It is not typical of occupational noise exposure (with the exception of exposure to music). The typical patient is relatively young, the mean age being approximately 10 years less than for a population of patients with tinnitus or noise-induced hearing loss. In addition to hypersensitivity to sound, the patients often suffer from tinnitus (86%). Sounds are frequently painful and exposure to loud sounds worsens the condition for some time. The patients often have headaches. Pure tone audiograms show normal hearing or a slight high tone loss. The uncomfortable loudness level is markedly decreased, mostly less than 90 dB HL. Patients with hyperacusis may also be divided into those hypersensitive to the loudness of sounds with a decreased pure tone uncomfortable loudness level and those hypersensitive to certain specific sounds irrespective of loudness showing relatively high pure tone uncomfortable loudness levels and decreased uncomfortable loudness levels to specific sounds. With a careful history other conditions with the symptom of hypersensitivity to sound can be excluded.

Comparison of arthroscopic one-incision and two-incision techniques for reconstruction of the anterior cruciate ligament

The purpose of this study was to assess the outcome of arthroscopic anterior cruciate ligament reconstruction performed using either the 'one-incision' technique or the rear-entry 'two-incision' technique. A series of 221 consecutive patients who underwent anterior cruciate ligament reconstruction was reviewed retrospectively. In the study population, two subgroups were defined. Group A consisted of 118 patients who underwent reconstruction using the one-incision transtibial endoscopic technique and Group B consisted of 103 patients who underwent reconstruction using the two-incision technique. The groups were comparable in terms of age, sex and activity level. The follow-up was performed after 47 (40-68) months in Group A and 55 (40-68) months in Group B. The Lysholm score at the final follow-up was significantly lower in Group A (90, 38-100) than in Group B (94, 34-100) (P = 0.002). The median KT-1000 total side-to-side difference was 1.5 (-6 to 7.5) mm in Group A, and 2.0 (-3.5 to 9) mm in Group B (n.s.). No significant difference between the groups was found when the IKDC evaluation system was used. Four intra-operative complications were registered in Group A and none in Group B (P = 0.06). No significant difference was found in terms of anterior knee pain, the one-leg-hop quotient or the activity level at the final follow-up. In this study the two methods gave similar and satisfactory results. Serious intraoperative complications were, however, recorded in four cases when the one-incision technique was used.

Subacute versus delayed reconstruction of the anterior cruciate ligament in the competitive athlete

The objective of this study was to compare the function and activity level in patients with anterior cruciate ligament injuries, who participated in competitive sports (Tegner activity level > or = 7) and underwent a reconstruction of the anterior cruciate ligament, either subacute (2-12 weeks, group I) or late (12-24 months, group II) after the injury. The patients in group I (n = 97) were comparable with those in group II (n = 103) in terms of gender, age, preinjury activity level, and the reconstruction technique. At the final follow-up (2-5.5 years after the operation), the Lysholm score, the IKDC evaluation system and the one-leg-hop test revealed no differences between the groups. There were also no differences between the groups in terms of the patients' subjective evaluation or expectations. The Tegner activity level at follow-up was 8 (range 2-10) in group I and 6 (range 2-9) in group II (P = 0.0001). The same thing was found in terms of the desired Tegner activity level, which was 9 (range 4-9) in group I and 7 (range 3-10) in group II (P = 0.0002). The KT-1000 laxity meter revealed a total side-to-side difference of 1.5 mm (-3.5-8.5) in group I and 1.5 mm (-3.5-7) in group II (NS). Associated meniscal surgery between the index injury and the reconstruction, or during the reconstruction, was performed in 37/97 (38%) of the patients in group I and 59/103 (57%) of the patients in group II (P < 0.01). This study revealed that competitive athletes who underwent reconstruction at a subacute stage after the anterior cruciate ligament injury had a higher activity level 2-5.5 years after the index operation, as well as a higher desired level of activity compared to athletes who had the reconstruction delayed by 12-24 months. Furthermore, meniscal injuries were significantly more frequent if the reconstruction was delayed.

Complications following arthroscopic anterior cruciate ligament reconstruction. A 2-5-year follow-up of 604 patients with special emphasis on anterior knee pain

The aim of the study was to assess knee function after arthroscopic anterior cruciate ligament reconstruction and to analyse complications impeding rehabilitation, additional surgery until the final follow-up, as well as residual patellofemoral pain and donor-site problems. Between 1991 and 1994, 635 patients were operated on using patellar tendon autografts and interference screw fixation. Of these, 604 (95.1%) patients (403 male and 201 female) were re-examined by independent observers at the final follow-up 38 (range 21-68) months post-operatively. The Lysholm score was 85 (range 14-100) points and the Tegner activity level was 6 (range 1-10). Using the IKDC score, 206 patients (34.1%) were classified as normal, 244 (40.4%) as nearly normal, 122 (20.2%) as abnormal and 32 (5.3%) as severely abnormal. In patients with an uninjured contralateral knee (n = 527), the KT-1000 revealed a total side-to-side difference of 1.5 (range -7-11) mm, and 384/527 (72.9%) had a side-to-side difference of < or = 3 mm. The one-leg-hop test was 95% (range 0%-167%). One or more complications impeding rehabilitation were recorded in 184/604 patients (30.5%). The most common was an extension deficit (> 5 degrees), in 81 patients (13.4%). During the period until the final follow-up, 196 re-operations were performed in 161/604 (26.7%) patients. More than one re-operation was required in 27 patients. Shaving and anterior scar resection due to extension deficit were the most common procedures performed (on 65 occasions). Moderate to severe subjective anterior knee pain related to activity, walking up and down stairs, and sitting with the knee flexed was found in 203/604 patients (33.6%). The median loss of anterior knee sensitivity was 16 (range 0-288) cm2. Patients with a full range of motion had less anterior knee pain than patients with isolated flexion or extension deficits, or combined flexion and extension deficits (P < 0.05, P = 0.08 and P < 0.001, respectively). Patients with a full range of motion had less anterior knee pain than patients with extension deficits (with and without flexion deficits) (P < 0.001). Patients with a full range of motion and a minimal loss (< or = 4 cm2) of anterior knee sensitivity had significantly (P < 0.01) less subjective anterior knee pain than patients who did not fulfil these criteria. A considerable number of complications hindering the rehabilitation and conditions requiring additional surgery until the final follow-up were recorded. Anterior knee pain and problems with knee-walking were correlated with the loss of range of motion and anterior knee sensitivity.

Effect of CPAP during cardiopulmonary bypass on postoperative lung function. An experimental study

BACKGROUND

Respiratory failure secondary to cardiopulmonary bypass (CPB) remains a major complication after cardiac surgery. We tested the hypothesis that post-CPB lung function impairment can be prevented by continuous positive airway pressure (CPAP) applied during the CPB.

METHODS

In 6 pigs, CPAP with 5 cmH2O pressure was applied during CPB. Six other pigs served as control, i.e. the lungs were open to the atmosphere during CPB. After median sternotomy, the right atrial appendage as well as the ascending aorta were cannulated. The total CPB duration was 90 min with 45 min cardioplegic arrest. Ventilation-perfusion distribution was measured with the multiple inert gas elimination technique and atelectasis by CT-scanning.

RESULTS

Large atelectasis appeared after CPB, corresponding to 14.5% +/- 5.5 (percent of the total lung area) in the CPAP group and 18.7% +/- 5.2 in the controls (P = 0.20). Intrapulmonary shunt increased and PaO2 decreased after the CPB in both groups.

CONCLUSIONS

We conclude that in this pig model post-CPB atelectasis is not effectively prevented by CPAP applied during CPB.

Using telematics with older people: the ACTION project. Assisting Carers using Telematics Interventions to meet Older persons' Needs

In this article, the authors provide an overview of the pan-European Assisting Carers using Telematics Interventions to meet Older persons' Needs (ACTION) project. They focus on the developmental aspects of the ACTION project and discuss ongoing work and future development plans.

Repeated vital capacity manoeuvres after cardiopulmonary bypass: effects on lung function in a pig model

Respiratory failure following cardiopulmonary bypass (CPB) is a major complication after cardiac surgery. A vital capacity inflation of the lungs, performed before the end of CPB, may improve gas exchange, but the necessity to repeat it is unclear. Therefore, we studied 18 pigs undergoing hypothermic CPB. A vital capacity manoeuvre (VCM) was performed in two groups and consisted of inflating the lungs for 15 s to 40 cm H2O at the end of CPB. In one group, VCM was repeated every hour. The third group served as controls. Atelectasis was studied by CT scan. Intrapulmonary shunt increased after bypass in the controls and improved spontaneously 3 h later without returning to baseline values. From 3 to 6 h after CPB, there was no more improvement and more than 10% atelectasis remained at 6 h. In contrast, the two groups treated before termination of CPB with VCM showed only minor atelectasis and no abnormal changes in gas exchange directly after bypass or later. We conclude that the protective effect of VCM remained for 6 h after bypass, and there was no extra benefit on gas exchange by repeating the VCM.

Visual reinforcement audiometry. Comparison of loudspeaker arrangements

Two different loudspeaker arrangements are currently used when performing Visual Reinforcement Audiometry (VRA). In the one arrangement, the loudspeakers are mounted on separate movable arms and positioned 15 cm from each ear. In the other, the loudspeakers are rigidly mounted close to their respective picture monitor at a distance of 50-70 cm from the child. In the present study, these two arrangements were compared by measuring real-ear sound pressure levels and actual sound field conditions. It was shown that a predominantly monaural stimulation was best achieved by using the 15-cm position, but also that the measurements were significantly more affected by small head movements when using this close position. When assessing the acoustics as well as practical aspects, it was concluded that loudspeakers mounted beside the picture monitors at a distance of 50-70 cm from the child makes a generally appropriate arrangement for VRA.

Use of a vital capacity maneuver to prevent atelectasis after cardiopulmonary bypass: an experimental study

BACKGROUND

Respiratory failure secondary to cardiopulmonary bypass (CPB) remains a major complication after cardiac surgery. The authors previously found that the increase in intrapulmonary shunt was well correlated with the amount of atelectasis. They tested the hypothesis that post-CPB atelectasis can be prevented by a vital capacity maneuver (VCM) performed before termination of the bypass.

METHODS

Eighteen pigs received standard hypothermic CPB (no ventilation during bypass). The VCM was performed in two groups and consisted of inflating the lungs during 15 s to 40 cmH2O at the end of the bypass. In one group, the inspired oxygen fraction (FIO2) was then increased to 1.0. In the second group, the FIO2 was left at 0.4. In the third group, no VCM was performed (control group). Ventilation-perfusion distribution was measured with the inert gas technique and atelectasis by computed tomographic scanning.

RESULTS

Intrapulmonary shunt increased after bypass in the control group (from 4.9 +/- 4% to 20.8 +/- 11.7%; P < 0.05) and was also increased in the vital capacity group ventilated with 100% oxygen (from 2.2 +/- 1.3% to 6.9 +/- 2.9%; P < 0.01) but was unaffected in the vital capacity group ventilated with 40% oxygen. The control pigs showed extensive atelectasis (21.3 +/- 15.8% of total lung area), which was significantly larger (P < 0.01) than the proportion of atelectasis found in the two vital capacity groups (5.7 +/- 5.7% for the vital capacity group ventilated with 100% oxygen and 2.3 +/- 2.1% for the vital capacity group ventilated with 40% oxygen.

CONCLUSION

In this pig model, postcardiopulmonary bypass atelectasis was effectively prevented by a VCM.

Anaesthesia for tracheal resection: report of 17 cases

PURPOSE

Laryngo-tracheal stenosis remains a major complication after prolonged intubation or tracheostomy. Surgical resection with end-to-end anastomosis carries the best long term prognosis. For the anaesthetist, however, this procedure represents a most challenging situation.

METHODS

Since 1993, we have used high frequency jet ventilation (HFJV) for tracheal resection. This paper describes the technique and the results of our series including 7 adults and 10 children.

RESULTS

There were no adverse haemodynamic or ventilatory consequences due to HFJV. Oxygenation was well maintained during the HFJV period. Sixteen of the 17 patients had a good outcome. Despite the good result of the resection-anastomosis, one child still suffers from an associated posterior glottic stenosis.

CONCLUSION

Since the introduction of HFJV for surgery of tracheal stenosis in our institution no complication of this ventilatory technique has occurred. It reduces the manipulation of the ventilation system and the period of apnea, thus decreasing the risk of hypoxaemia. The good access to the surgical field contributes to the success of resection-anastomoses in laryngo-tracheal stenosis.

Atelectasis is a major cause of hypoxemia and shunt after cardiopulmonary bypass: an experimental study

BACKGROUND

Respiratory failure after cardiopulmonary bypass (CPB) remains a major complication after cardiac surgery. The authors tested the hypothesis that atelectasis is an important factor responsible for the increase in intrapulmonary shunt after CPB.

METHODS

Six pigs received standard CPB (bypass group). Six other pigs had the same surgery but without CPB (sternotomy group). Another six pigs were anesthetized for the same duration but without any surgery (control group). The ventilation-perfusion distribution was measured with the inert gases technique, extravascular lung water was quantified by the double-indicator distribution technique, and atelectasis was analyzed by computed tomography.

RESULTS

Intrapulmonary shunt increased markedly after bypass but was unchanged over time in the control group (17.9 +/- 6.2% vs. 3.5 +/- 1.2%; P < 0.0001). Shunt also increased in the sternotomy group (10 +/- 2.6%; P < 0.01 compared with baseline) but was significantly lower than in the bypass group (P < 0.01). Extravascular lung water was not significantly altered in any group. The pigs in the bypass group showed extensive atelectasis (32.3 +/- 28.7%), which was significantly larger than in the two other groups. The pigs in the sternotomy group showed less atelectasis (4.1 +/- 1.9%) but still more (P < 0.05) than the controls (1.1 +/- 1.6%). There was good correlation between shunt and atelectasis when all data were pooled (R2 = 0.67; P < 0.0001).

CONCLUSIONS

Atelectasis is produced to a much larger extent after CPB than after anesthesia alone or with sternotomy and it explains most of the marked post-CPB increase in shunt and hypoxemia. Surgery per se contributes to a lesser extent to postoperative atelectasis and gas exchange impairment.

Predicting the speech recognition performance of elderly individuals with sensorineural hearing impairment. A procedure based on the Speech Intelligibility Index

The Speech Intelligibility Index (SII) was used as a basis for predicting the performance of elderly hearing-impaired subjects on a speech-in-noise test. The standard SII calculation scheme was compared with modified schemes, and correlations were obtained between measured and predicted scores. The results suggested that a modified calculation scheme, which includes corrections for sensorineural hearing impairment and age, is appropriate for evaluating individual speech recognition scores. Based on the results, a computer program has been developed for clinical prediction and evaluation of speech recognition scores.

Speech intelligibility index transfer functions and speech spectra for two Swedish speech recognition tests

Speech spectra and Speech Intelligibility Index (SII) transfer functions are presented for the Swedish PB word material (SPB) and for a Swedish sentence material known as Hagerman's Sentences (HS). The transfer function were derived from the normative recognition scores in noise previously obtained from normal-hearing subjects. The transfer function for HS is very similar to a transfer function for familiar English sentences. The function for SPB is more like functions of other monosyllabic word test materials. The slope of the HS transfer function is twice as steep as the slope of the SPB function. The long-term rms spectra of the speech materials and their associated noise signals are presented and recommended to facilitate accurate SII calculations with these speech tests.

Reliable clinical determination of speech recognition scores using Swedish PB words in speech-weighted noise

Results of speech recognition tests with competing sound obtained by the use of standard audiometric equipment will suffer from considerable systematic errors because of normal calibration variability. To avoid this, and to keep the reliability high, not only in investigative situations but also in clinical practice, it is highly recommended that test materials be used with speech and noise mixed in the recording. Considering this, a test material was developed consisting of six Swedish PB word lists and speech-weighted noise pre-mixed with a fixed speech-to-noise ratio and recorded on compact disc. This material was investigated for list equality, and normative recognition data were obtained. The material was found to be reliable and suitable for clinical use.

[Elevation of arterial pressure during surgery with a pneumatic tourniquet: an independent action of renin?]

The aim of this study was to evaluate the effectiveness of captopril for the prevention of the increase of arterial pressure during orthopaedic surgery requiring the application of lower limb tourniquets with balanced anaesthesia. Twenty consecutive patients were included in the study and were randomly divided into two groups. The first (n = 10) received 50 mg captopril orally together with the preanaesthetic medication, the second (n = 10) received a placebo at the same time. The different variables studied (arterial pressure, heart rate) were continuously measured. This study demonstrated that the pretreatment with captopril did not prevent an increase of the arterial pressure during the application of a tourniquet. The means of the systolic and diastolic arterial pressures at the end of the application of the tourniquet were 128/86 and 128/81 in the captopril group and the placebo group, respectively. This result shows that the renin-angiotensin system does not significantly contribute to the increase of the arterial pressure induced by a tourniquet.