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Biomedical subjects

J Qvist

Publications and source records attributed to J Qvist.

At least 37 records · Page 2Linked to original sources
PubMed1993

[CT and magnetic resonance imaging and spectroscopy for non-invasive study of regeneration of skeletal musculature after intensive therapy].

UNLABELLED: A 50 year old man was treated in the intensive care unit. Due to a prolonged catabolic state with a loss of 35 kg of body weight, he was practically paralyzed following 70 days of treatment. After 200 days of intensive physical training, he had recuperated remarkably. CT-scans before and after the physical training revealed 90-180% increase in the muscles examined. At the femoral level the muscle/fat ratio increased from 40% to 70%, indicating less atrophy. MR-imaging of the crural muscles showed a substantial increase in the muscle mass after training. MR-fat/water proton spectra showed a decrease in the relative fat content from 0.31 to 0.13 during training, objectively measuring the remission of the severe atrophy. CONCLUSION: CT- and MR-techniques can be used for objective, non-invasive, evaluations of muscle condition, and MR-proton spektroscopy can probably be used for following the remission of muscle atrophy during physical training.

Critical Care↗
PubMed1993

Regional diaphragmatic length and EMG activity during inspiratory pressure support and CPAP in awake sheep.

We examined diaphragmatic mechanics in awake sheep during quiet breathing (QB) and the randomized application of 5, 10, and 15 cmH2O continuous positive airway pressure (CPAP), inspiratory pressure support (IPS), and equal combinations of IPS and CPAP (IPS/CPAP). We measured esophageal, gastric, and transdiaphragmatic (Pdi) pressures and regional length, shortening, and electromyogram (EMG) activity of both costal and crural diaphragmatic segments. Segmental resting length normalized to QB decreased during 15 cmH2O CPAP (costal, 19.2 +/- 3.3%; crural, 7.5 +/- 2.1%; P < 0.05) and during 15/15 cmH2O IPS/CPAP (costal 25.3 +/- 4.8%, crural 9.9 +/- 2.6%; P < 0.05). Only during 15 cmH2O IPS did costal shortening fraction increase (67% QB; P < 0.05). Compared with QB, during 15 cmH2O CPAP, end-tidal CO2 increased 6 Torr, regional EMG activity increased threefold, and Pdi increased 58%. During 15 cmH2O IPS these values decreased 3 Torr, threefold, and 44% respectively, but during IPS/CPAP they remained unchanged. Expiratory gastric pressure (Exp-Pga) reached 4.3 +/- 0.4 cmH2O at 15 cmH2O CPAP, but during IPS/CPAP Exp-Pga was less (maximum of 1.7 +/- 0.4 cmH2O) than at comparable CPAP (P < 0.05), despite the shorter diaphragmatic length. We conclude that: 1) IPS alters the actions of the diaphragm during CPAP, 2) Exp-Pga is poorly coupled to diaphragmatic end-expiratory length, and 3) both IPS and the release of Exp-Pga assist active diaphragmatic shortening.

Animals↗
PubMed1993

Arterial blood gas tensions during breath-hold diving in the Korean ama.

Korean female unassisted divers (cachido ama) breath-hold dive > 100 times to depths of 3-7 m during a work day. We sought to determine the extent of arterial hypoxemia during normal working dives and reasonable time limits for breath-hold diving by measuring radial artery blood gas tensions and pH in five cachido ama who dove to a fixed depth of 4-5 m and then continued to breath hold for various times after their return to the surface. Eighty-two blood samples were withdrawn from indwelling radial artery catheters during 37 ocean dives. We measured compression hyperoxia [arterial PO2 = 141 +/- 24 (SD) Torr] and hypercapnia (arterial PCO2 = 46.6 +/- 2.4 Torr) at depth. Mean arterial PO2 near the end of breath-hold dives lasting 32-95 s (62 +/- 14 s) was decreased (62.6 +/- 13.5 Torr). Mean arterial PCO2 reached 49.9 +/- 5.4 Torr. Complete return of these values to their baseline did not occur until 15-20 s after breathing was resumed. In dives of usual working duration (< 30 s), blood gas tensions remained within normal ranges. Detailed analysis of hemoglobin components and intrinsic oxygenation properties revealed no evidence for adaptive changes that could increase the tolerance of the ama to hypoxic or hypothermic conditions associated with repetitive diving.

2,3-Diphosphoglycerate↗
PubMed1993

Continuous pulse oximetry in the breath-hold diving women of Korea and Japan.

Arterial oxygen saturation during breath-hold diving has not previously been measured continuously. We devised a submersible, waterproof, backpack computer to continuously record heart rate, depth, and arterial oxygen saturation (SPO2) as determined by earlobe pulse oximetry. Our measurements showed that one assisted (Funado) diver had reduced SPO2 values immediately after surfacing from 22 dives which lasted 23-76 s, from a mean of 99 +/- 1% SPO2 to 96 +/- 3% SPO2. SPO2 returned to 97 +/- 2% within 15 s after surfacing (P < 0.05 surface value differs from predive base line). Four unassisted (Cachido) divers showed no significant reduction of mean predive SPO2 below 98 +/- 2% at any time during the dive or recovery period in 92 routine dives lasting from 15 to 44 s. Upon surfacing from diving, mean SPO2 was 98 +/- 2% and the mean SPO2 15 s after surfacing was 97 +/- 3% for the unassisted divers. Three Cachido divers were asked to dive and breath hold for as long as possible. Mean SPO2 at the conclusion of breath holding was 73% after an average dive and breath hold lasting 69 s.

Adult↗
PubMed1992

Pulmonary vascular lesions in the adult respiratory distress syndrome caused by inhalation of zinc chloride smoke: a morphometric study.

Two soldiers were fatally injured by accidental inhalation of zinc chloride (ZnCl2) from a smoke bomb. Although exposed to a relatively short but high smoke concentration, acute injury was minor and for 10 days the patients were clinically satisfactory. Unexpectedly, both then rapidly developed features typical of severe adult respiratory distress syndrome with pulmonary hypertension. Intubation and mechanical ventilation were instigated on day 15 (patient no. 1) and day 12 (patient no. 2) after the inhalation, but death followed at days 25 and 32, respectively. Lung vascular injury was assessed by angiography and morphometric techniques. The lungs showed extensive interstitial and intra-alveolar space fibrosis. Vessels showed a significant lumen reduction by contracture (that is, reduction in vessel external diameter) affecting preacinar and intraacinar arterial and venous segments, the extent of injury suggesting that hexite causes more severe venous injury than seen in other types of adult respiratory distress syndrome. In microvessels there was obliteration and widespread occlusion by endothelial cell proliferation and clot. No evidence of infection was identified during life or at autopsy. It is unclear whether the long lag time was due to the fact that the infection was not a complicating event or because steroids, administered prophylactically, had sufficed to delay, but not to prevent, the amplification of injury that seems responsible for the adult respiratory distress syndrome.

Adult↗
PubMed1992

Epidemiology of intensive care.

It is difficult to study the epidemiology of ICUs, as they lack a uniform nomenclature and/or classification. The organization and distribution of intensive care medicine depend on the size and function of the hospital. The patients in ICUs are predominantly men, with a high proportion of elderly patients (greater than or equal to 70 years) constituting 25-30% of the total. Case-mix, severity of illness and outcome differ from one unit to another, and can be compared only if the patients are classified with a common classification system. Most survivors of intensive care seem to return to normal or near normal functional level within one year. Compared to Western Europe, the United States has more ICU beds and a nearly ten times higher admission rate to intensive care. These variations can be seen as a result of a fundamental difference in the attitudes toward withdrawing or withholding life support.

Aged↗
PubMed1992

The nursing care recording system. A preliminary study of a system for assessment of nursing care demands in the ICU.

A new system, Nursing Care Recording (NCR), for the recording of nursing care in a general ICU is presented. NCR classifies ICU patients according to their need for intensive nursing care. Comparing the NCR with the Therapeutic Intervention Scoring System (TISS), a correlation coefficient of 0.60 was found. The main difference between the two systems was related to recording procedures allowing changes in nursing intensity within a 24-h period, reflecting patient improvement due to therapy, which was detected by NCR but not by TISS. NCR can be used to estimate nursing capacity during different shifts and may be useful in the assessment of the total nursing staff necessary for a given ICU. It is suggested that NCR will allow detection of changes in the nursing care work load, whether this change is due to new activities in the unit or to alterations in the individual patient care.

Adult↗
PubMed1992

Nitrogen tensions in brachial vein blood of Korean ama divers.

Intravascular bubble formation and symptoms of decompression sickness have been reported during repetitive deep breath-hold diving. Therefore we examined the pattern of blood N2 kinetics during and after repetitive breath-hold diving. To study muscle N2 uptake and release, we measured brachial venous N2 partial pressure (PN2) in nine professional Korean breath-hold divers (ama) during a 3-h diving shift at approximately 4 m seawater depth and up to 4 h after diving. PN2 was determined with the manometric Van Slyke method. Diving time and depth were recorded using a backpack computer-assisted dive longer that allowed calculating the surface-to-depth time ratio to derive the effective depth. With the assumption that forearm muscle N2 kinetics follow the general Haldanian principles of compression and decompression, i.e., forearm muscle is a single compartment with a uniform tissue PN2 equal to venous PN2, PN2 data were fitted to monoexponential functions of time. In the early phase of the diving shift, PN2 rapidly increased to 640 Torr (half time = 6 min) and then slowly declined to baseline levels (half time = 36 min) after the work shift. Peak PN2 levels approximated the alveolar PN2 derived from the effective depth. We conclude that forearm muscle N2 kinetics are well described by a Haldanian single-compartment model. Decompression sickness is theoretically possible in the ama; it did not occur because the absolute PN2 remained low due to the shallow working depth of the ama we studied.

Diving↗
PubMed1990

[Convulsions after flumazepil].

Two cases of convulsions following intake of the benzodiazepine antagonist, flumazepil, are presented. The etiology is discussed and special precautions are recommended for the diagnostic employment of the preparation.

Adult↗
PubMed1990

Long-term relative survival rates after heart valve replacement.

The calculation and comparison of relative survival rates after interventional studies is a method that permits correction for important demographic variables, thereby adjusting for the "background mortality" in the general population. Long-term relative survival rates were analyzed in a consecutive series of 2,805 Swedish patients who, on the basis of clinical symptoms, underwent aortic valve replacement (n = 1,741), mitral valve replacement (n = 792) and double (aortic plus mitral) valve replacement (n = 272) between 1969 and 1983. The follow-up period, which closed August 1, 1985, included 100% of patients and covered 16,822 patient-years. Autopsy was performed in 75% of all deaths. The results underscore previously well known differences between the long-term survival after aortic valve replacement and mitral or double valve replacement, whereas no differences were noted between mitral and double valve replacement. Within the subgroup undergoing aortic valve replacement, analysis of relative survival rates disclosed a highly significant (p less than 0.001) difference between patients operated on for aortic stenosis and those operated on for aortic regurgitation, representing a mortality rate more than twice as high in the latter group. This difference was of much lesser magnitude when analyzed in the standard (actuarial) way. With a low (less than 2.5%) operative mortality rate for patients undergoing isolated elective aortic valve replacement in the current era and with an acceptable incidence of late valve-related death (5.2% at 10 years), these results may justify aortic valve replacement earlier in the course of chronic aortic regurgitation to prevent irreversible myocardial damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1990

Placement and longevity of amalgam restorations in Denmark.

A survey has been made of the reasons for placement of 4932 amalgam restorations in Denmark. In patients more than 16 years of age 39% of all restorations were made because of primary caries, and 61% were replacements of failed restorations. In children 74% of the restorations in primary teeth and 84% of those in permanent teeth were inserted because of primary caries. The reasons for replacement of restorations depended on dentition, age of the patient, and type of restoration. Secondary caries was the most frequent reason for replacement of failed restorations in permanent teeth and accounted for 38% of all failures. Marginal discrepancies and bulk fracture of fillings were the other two major reasons. In primary teeth fracture and loss of fillings were the commonest reasons, whereas secondary caries accounted for only a quarter of all restorations replaced. The age of the restorations replaced ranged from 0 to 46 years, and half of the failed restorations in permanent teeth of adults were more than 8 years old. A shorter longevity of failed restorations was noted in primary teeth and permanent teeth of children.

Adolescent↗
PubMed1990

Placement and longevity of tooth-colored restorations in Denmark.

A survey has been made of the use of materials and the reasons for placement of 2542 tooth-colored restorations in Denmark. In adults 38% of all the restorations were inserted because of primary caries, and 62% were replacements of failed restorations. In children primary caries was the reason for placing 68% of the restorations in deciduous teeth and 77% of those in permanent teeth. Resin-based materials were the most frequently used tooth-colored restorative, except in the treatment of deciduous teeth, for which glass ionomer cement was used preferentially. Silicate cement was used for less than 2% of the tooth-colored restorations, and the few old silicate cement restorations were most often replaced with resin materials. The reasons for replacement of resin restorations were dependent on dentition, age of the patient, and type of restoration. Secondary caries, fracture of restoration, and loss of fillings were the most frequently recorded failures. The age of the resin restorations replaced ranged from 0 to 19 years, and half of the failed restorations in adults were more than 6 years old. In permanent teeth in children half of the failed resin restorations were replaced within 2 years, whereas half of those in primary teeth were replaced within 1 year.

Adolescent↗
PubMed1989

Interhospital comparisons of patient outcome from intensive care: importance of lead-time bias.

We studied 432 admissions to two Danish ICUs by using a standard severity of illness classification system to assess utilization and outcome. Substantial differences in utilization were found. The patients in Hospital 2 were younger, had better previous health records, and were admitted significantly more often for active treatment as opposed to monitoring than the patients in Hospital 1. Although their measured severity of illness was similar, patients at Hospital 2 received significantly more therapy and their mortality exceeded that of the patients at Hospital 1. The mortality rate of Hospital 2 also exceeded that predicted from a recent survey of U.S. hospitals. We found, however, that 35% of the patients at Hospital 2 had been transferred to the ICU from other ICUs. This created the possibility of an adverse selection and lead-time bias for the patients at Hospital 2. These findings indicate that although national and international comparisons of intensive care are now possible using common classification systems, this progress has created a new need for more precise measurement of potential confounding biases, such as the duration of intensive care services received before formal ICU admission.

Adult↗
PubMed1989

Sonomicrometric regional diaphragmatic shortening in awake sheep after thoracic surgery.

Through a right thoracotomy in seven sheep we chronically implanted sonomicrometry crystals and electromyographic electrodes in the costal and crural diaphragmatic regions. Awake sheep were studied during recovery for 4-6 wk, both during quiet breathing (QB) and during CO2 rebreathing. Tidal volume, respiratory frequency, and esophageal and gastric pressures were studied before and after surgery. Normalized resting length (LFRC) was significantly decreased for the costal segment on postoperative day 1 compared with postoperative day 28. Fractional costal shortening both during QB and at 10% end-tidal CO2 (ETCO2) increased significantly from postoperative days 1 to 28, whereas crural shortening did not change during QB but progressively increased at 10% ETCO2. Maximal costal shortening during electrophrenic stimulation was constant at 40% LFRC during recovery, although maximal crural shortening increased from 23 to 32% LFRC. Minute ventilation, tidal volume, and transdiaphragmatic pressure at 10% ETCO2 increased progressively after thoracotomy until postoperative day 28. Our results suggest there is profound diaphragmatic inhibition after thoracotomy and crystal implantation in sheep that requires at least 3-4 wk for stable recovery.

Animals↗
PubMed1989

Ventilation-perfusion distributions and central hemodynamics in chronic obstructive pulmonary disease. Effects of terbutaline administration.

We studied the effects of intravenous terbutaline on VA/Q distributions and central hemodynamics in 11 patients with mixed-type COPD. Terbutaline caused an increase in VA/Q inequality in patients having PaO2 values greater than 60 mm Hg which resulted in a moderate fall in the PaO2. Patients with PaO2 values less than 60 mm Hg, the highest mean PAPs and the poorest spirometric performances demonstrated no significant changes in VA/Q distributions or PaO2 after terbutaline. Cardiac output increased 40 to 60 percent in all patients after terbutaline with an increase in tissue oxygen delivery. Mean PAP did not change in any patient after terbutaline and pulmonary vasodilatation was indicated by a decrease of calculated static PVR. The decrease of PaO2 after terbutaline in COPD is related to a further deterioration of existing VA/Q relationships. The cause of these effects and lack of such responses in patients with more advanced disease are discussed.

Aged↗
PubMed1989

Human pulp reactions to resin restorations performed with different acid-etch restorative procedures.

Fifty-eight experimental resin restorations were performed in intact, human premolars, using different leakage-reducing restorative procedures. These were conventional acid-etching and acid-etching followed by cavity treatment with an intermediary layer of low-viscous resin or the dentin adhesive NPG-GMA/ethanol. The teeth were extracted after 4 months and examined for pulpal inflammation/necrosis (I), reduction of odontoblasts (OR), and formation of tertiary dentin (TD). By the general linear model procedure, 91%, 34%, and 56% of the variations in I, OR, and TD, respectively, could be explained by variations in the experimental conditions. The significant independent variables were jaw, stage of root formation, width of pulp, width of cavity, marginal leakage, bacteria in the cavity, bacteria in the exposed dentinal tubules, and the restorative procedure. With regard to the restorative procedure the analyses showed that application of low-viscous resin increased the pulpal reactions OR and I, whereas cavity treatment with NPG-GMA/ethanol had no adverse biologic effect.

Acid Etching, Dental↗
PubMed1989

Outcome from intensive care. I. A 5-year study of 1308 patients: methodology and patient population.

During a 5-year period, from 1979 to 1983, demographic and disease-related data were collected prospectively on 1308 adult patients from 1555 admissions to a multidisciplinary intensive care unit (ICU) in a Danish university hospital. The patients were followed during the stay in ICU, the ensuing hospital stay, and up to 8 years after discharge from hospital. The male: female ratio was 1:1. One-third of the patients were admitted from medical wards, two-thirds were surgical patients (including gynaecological and obstetric patients). Median age was 60 years, and 25% of the patients were aged 70 years and older. Median length of stay in ICU was 2 days, and the median length of the ensuing hospital stay was 10 days. Respiratory diseases (43%) and cardiovascular diseases (16%) were the most common primary indications for ICU admission; increasing age was associated with more frequent cardiovascular diseases. Six-hundred and twenty-three (48%) patients needed mechanical ventilation; of these 373 were on mechanical ventilation for more than 24 h. Increasing age was associated with a more frequent need for mechanical support. Cancer was diagnosed in 290 patients prior to ICU admission. In 41% the cancer originated from the digestive tract. Cancer was more frequent in surgical patients than in medical patients. The APACHE- and TISS-systems were simultaneously applied to a representative sample of 216 consecutive admissions. The average APACHE score was 14.9 +/- 8.2 and the average TISS score 28.3 +/- 11.1 points. The ICU patients presented in this paper do not differ much from ICU patients in other outcome studies.

Adult↗