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Biomedical subjects

L Magnusson

Publications and source records attributed to L Magnusson.

32 records · Page 2Linked to original sources
PubMed1997

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.

Adult↗
PubMed1997

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.

Animals↗
PubMed1997

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.

Adult↗
PubMed1996

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.

Hearing↗
PubMed1996

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.

Age Factors↗
PubMed1995

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.

Adolescent↗
PubMed1993

[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.

Adult↗
PubMedDate not supplied

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.

Adolescent↗
PubMedDate not supplied

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.

Age Factors↗