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Biomedical subjects

G H Fick

Publications and source records attributed to G H Fick.

At least 19 recordsLinked to original sources
PubMed2006

A multi-centre randomized controlled trial comparing electrothermal arthroscopic capsulorrhaphy versus open inferior capsular shift for patients with shoulder instability: protocol implementation and interim performance: lessons learned from conducting a multi-centre RCT [ISRCTN68224911; NCT00251160].

BACKGROUND: The shoulder is the most frequently dislocated joint in the body. Multiple causes and pathologies account for the various types of shoulder instability. Multi-directional instability (MDI) and multi-directional laxity with antero-inferior instability (MDL-AII) are similar in pathology, less common and more difficult to treat. These instabilities are caused by ligamentous capsular redundancy. When non-operative management fails for these patients, quality of life is significantly impaired and surgical treatment is required to tighten the ligaments and joint capsule. The current reference (gold) standard treatment for MDI/MDL-AII is an open inferior capsular shift (ICS) surgical procedure. An alternative treatment involves arthroscopic thermal shrinkage of redundant capsular tissue to tighten the joint. However, there is a lack of scientific evidence to support the use of this technique called, electrothermal arthroscopic capsulorrhaphy (ETAC). This trial will compare the effectiveness of ETAC to open ICS in patients with MDI and MDL-AII, using patient-based quality of life outcome assessments. METHODS: This study is a multi-centre randomized clinical trial with a calculated sample size of 58 patients (p = 0.05, 80% power). Eligible patients are clinically diagnosed with MDI or MDL-AII and have failed standardized non-operative management. A diagnostic shoulder arthroscopy is performed to confirm eligibility, followed by intra-operative randomization to the ETAC or ICS surgical procedure. The primary outcome is the disease-specific quality of life questionnaire (Western Ontario Shoulder Instability Index), measured at baseline, 3, 6, 12 and 24 months. Secondary outcomes include shoulder-specific measures (American Shoulder and Elbow Surgeons Score and Constant Score). Other outcomes include recurrent instability, complications and operative time. The outcome measurements will be compared on an intention-to-treat basis, using two-sample independent t-tests to assess statistical significance. A Generalized Estimated Equations (GEE) analysis will determine whether there is an effect over time. DISCUSSION: This ongoing trial has encountered unexpected operational and practical issues, including slow patient enrollment due to high intra-operative exclusion rates. However, the authors have a greater understanding of multi-directional laxity in the shoulder and anticipate the results of this trial will provide the medical community with the best scientific clinical evidence on the efficacy of ETAC compared to open ICS.

Journal Article↗
PubMed2003

Diagnostic reasoning strategies and diagnostic success.

PURPOSE: Cognitive psychology research supports the notion that experts use mental frameworks or "schemes", both to organize knowledge in memory and to solve clinical problems. The central purpose of this study was to determine the relationship between problem-solving strategies and the likelihood of diagnostic success. METHODS: Think-aloud protocols were collected to determine the diagnostic reasoning used by experts and non-experts when attempting to diagnose clinical presentations in gastroenterology. RESULTS: Using logistic regression analysis, the study found that there is a relationship between diagnostic reasoning strategy and the likelihood of diagnostic success. Compared to hypothetico-deductive reasoning, the odds of diagnostic success were significantly greater when subjects used the diagnostic strategies of pattern recognition and scheme-inductive reasoning. Two other factors emerged as independent determinants of diagnostic success: expertise and clinical presentation. Not surprisingly, experts outperformed novices, while the content area of the clinical cases in each of the four clinical presentations demonstrated varying degrees of difficulty and thus diagnostic success. CONCLUSIONS: These findings have significant implications for medical educators. It supports the introduction of "schemes" as a means of enhancing memory organization and improving diagnostic success.

Clinical Competence↗
PubMed2000

Gastric distension and ventilation during laparoscopic cholecystectomy: LMA-Classic vs. tracheal intubation.

PURPOSE: The standard laryngeal mask airway LMA-Classic was designed as an alternative to the endotracheal tube (ETT) or the face mask for use with either spontaneous or positive pressure ventilation. Positive pressure ventilation may exploit leaks around the LMA cuff, leading to gastric distension and/or inadequate ventilation. We compared gastric distension and ventilation parameters with LMA vs ETT during laparoscopic cholecystectomy. METHODS: One hundred and one, ASA I-II adults scheduled for elective laparoscopic cholecystectomy were randomly assigned to LMA-Classic or ETT. Patients with BMI >30 kg x m(-2), hiatus hernia or gastroesophageal reflux were excluded. Following induction of anesthesia, an in-and-out orogastric tube was passed to decompress the stomach before insertion of the LMA (women size #4, men size #5) or ETT (women 7 mm, men 8 mm). Anesthesia was maintained with isoflurane in nitrous oxide and oxygen (FIO2 0.3-0.5), rocuronium and fentanyl. The surgeon, blinded to the type of airway, scored gastric distention 0-10 at insertion of the laparoscope and immediately before removal at the end of the surgical procedure. RESULTS: Incidence and degree of change in gastric distension were similar in both groups. Ventilation parameters during insufflation (mean +/- SD) for LMA and ETT were: S(P)O2 98 +/- I vs 98 +/- I, P(ET)CO2 38 +/- 4 vs 36 +/- 4 mm Hg and airway pressure 21 +/- 4 vs 23 +/- 3 cm water. CONCLUSION: Positive pressure ventilation with a correctly placed LMA-Classic of appropriate size permits adequate pulmonary ventilation. Gastric distension occurs with equal frequency with either airway device.

Adult↗
PubMed1999

Skiing and snowboarding injuries in the children and adolescents of Southern Alberta.

OBJECTIVE: To identify injuries and profile the characteristics of injured skiers and snowboarders younger than 18 years of age in Southern Alberta, Canada. DESIGN: Case-series over one year. PARTICIPANTS: Injured skiers and snowboarders younger than 18 years of age presenting to the ski patrol members at each of seven ski areas in Southern Alberta. MAIN OUTCOME MEASURES: Information on injured individuals reporting to the ski patrol at the involved areas was documented on a standardized injury reporting form. Anonymous information was then copied and sent to the University of Calgary Sport Medicine Centre, where the data were analyzed. Proportions of injured skiers and snowboarders with specific characteristics or participating in specific environmental conditions are presented. RESULTS: There were a total of 832 (60.0%) injury reports filed for skiers and 557 (40.1%) for snowboarders, reflecting 1,635 separate injuries. Head injuries were the most frequently reported (19.1% of all regional injuries). The most commonly injured region was the knee among skiers (n = 213; 22.8%) and the wrist among snowboarders (n = 173; 27.8%). Lower extremity injuries in skiers and upper extremity injuries in snowboarders were most common. Younger male skiers and snowboarders reported high proportions of head, neck, and back injuries. CONCLUSION: The lower extremity in skiers and the upper extremity in snowboarders were most susceptible to injury. A cause for concern is the high proportion of head injuries reported for both male skiers and snowboarders of younger age groups. Further study into protective equipment design and function is required.

Adolescent↗
PubMed1998

Plasma L-arginine concentration, oxygenation index, and systemic blood pressure in premature infants.

OBJECTIVE: To determine the relationships between plasma L-arginine concentrations and the severity of respiratory distress syndrome (RDS) or systemic blood pressure in premature infants. DESIGN: Prospective, observational study. SETTING: Neonatal intensive care, tertiary referral hospital. SUBJECTS: Fifty-three premature infants. INTERVENTIONS: We measured arginine and nutritional intake, plasma arginine concentration, total amino acid concentrations, and blood pressure on days 3, 7, 14, and 21 of life. In 33 infants who received assisted ventilation, oxygenation index could be calculated to reflect the severity of RDS. The relationships between plasma arginine and oxygenation index or blood pressure were analyzed using multiple linear regression. MEASUREMENTS AND MAIN RESULTS: On day 3, plasma arginine concentrations were decreased compared with normal published values. Arginine concentrations increased with the day of life of measurement (p < .001) and with arginine intake (p < .001). After adjusting for arginine intake and day of life, an inverse relationship was found between oxygenation index and plasma arginine concentrations: (p = .025). No similar relationship was found between oxygenation index and the concentration of total amino acids. A weak positive relationship was found between plasma arginine concentration and systemic blood pressure. CONCLUSIONS: Increments in the oxygenation index, reflective of an increased severity of RDS, are associated with a decrease in plasma arginine concentration. This finding may reflect arginine consumption by the nitric oxide synthase pathway in the lungs of premature infants with RDS, or may be explained by increased arginine catabolism. The lack of a similar relationship between total plasma amino acids and oxygenation index supports the first interpretation.

Amino Acids↗
PubMed1998

Increased intestinal permeability is associated with the development of multiple organ dysfunction syndrome in critically ill ICU patients.

We conducted a prospective, observational cohort study designed to compare intestinal permeability (IP) and development of multiple organ dysfunction syndrome (MODS) in a subset of critically ill patients in an intensive care unit (ICU). All patients with an expected ICU stay of 72 h or more were entered into the study, and IP was determined on a daily basis whenever possible from the urinary fractional excretion of orally administered lactulose and mannitol (LMR). Forty-seven consecutive patients were studied, and 28 developed MODS either at the time of admission or during their ICU course. These patients, as a group, had significantly worse IP at admission than did a non-MODS cohort (LnLMR: -2.10 +/- 1.10 versus -3.26 +/- 0.83). Those patients who developed MODS following admission also had a significantly greater admission IP than did the non-MODS group (-2.51 +/- 0.85). Differences in IP between cohorts could not be explained by differences in the incidence of systemic inflammatory response syndrome (SIRS)/sepsis or shock. With multivariate regression analysis, the only parameter present on admission that was predictive of subsequent MODS was IP. Differences in IP and the severity of organ dysfunction were also present (MODS severity mild: -3.01 +/- 0.72; moderate: -1.97 +/- 0.69; and severe: -1.12 +/- 0.96). Patients who developed MODS had a persistently abnormal IP during their ICU stay, and a significantly delayed improvement in their IP compared with the non-MODS cohort. We conclude that the development of MODS is associated with an abnormal and severe derangement of IP that is detectable prior to the onset of the syndrome. This observation lends credence to the premise that gastrointestinal (GI) dysfunction may be causally associated with the development of MODS in the critically ill patient.

Adult↗
PubMed1997

First year serologic response to treatment for syphilis: a model for prediction of seroreversion.

There is no straightforward test available, within weeks of treatment for syphilis, to assess adequacy of serologic response. We propose a method to predict non-treponemal seroreversion based on short term response. To develop and illustrate this method, we used data from 370 individuals with infectious syphilis. Individual serologic response appears to be a linear function of (log) time, suggesting the possibility of using rapid plasma reagin titres recorded in the first few months after treatment to determine the slope of the linear treatment response line. The slope of the response line, during the first year after treatment, is an important predictor of seroreversion but must be considered in conjunction with pre-treatment titre. We recommend development of an action line be developed based on these variables. Such a line would indicate the necessity for retreatment if the line plotted from the patient's first year response failed to fall below the action line.

Adult↗
PubMed1997

Assessment of lack of fit in simple linear regression: an application to serologic response to treatment for syphilis.

A patient treated for infectious syphilis is cured when serologic tests become non-reactive, which may take years to achieve. Our objective is to develop a method to determine, within months, whether the patient has responded adequately to treatment. Previous research and our exploratory graphical analysis suggested that treatment response is linear when we applied logarithmic transformations of the axes. If the response to treatment is linear, titres recorded within the first few months of treatment will determine the slope of the line and one can develop an action line in future research. We used a non-parametric method to assess whether the logarithmic transformation improved the linearity and then we applied three different methods of testing lack of fit in linear regression. Based upon a sample size that reflects a clinically reasonable number of data points, the results of these tests provided no evidence against linearity.

Alberta↗
PubMed1997

Plasma L-arginine concentrations in premature infants with necrotizing enterocolitis.

OBJECTIVE: To determine whether L-arginine concentrations (the substrate for nitric oxide synthesis) are lower in premature infants in whom necrotizing enterocolitis (NEC) develops than in unaffected infants. METHODS: We measured arginine and nutritional intake, plasma arginine, glutamine, total amino acids, and ammonia concentrations in 53 premature infants (mean gestational age +/- SD: 27 +/- 1.7 weeks) at risk of NEC. Measurements were done on days 3, 7, 14 and 21 and just before treatment in infants with NEC. RESULTS: Necrotizing enterocolitis developed in 11 infants between postnatal days 1 and 26. On day 3, plasma arginine concentrations were decreased compared with normal published values (mean +/- SE, 41 mumol/L +/- 4). Arginine concentrations increased with day of life of measurement (p < 0.001) and arginine intake (p < 0.001). Plasma arginine concentrations were significantly lower at the time of diagnosis in infants with NEC compared with control subjects, even after adjusting for arginine intake and day of life (p = 0.032). Plasma glutamine and total amino acid concentrations were not significantly different in infants with NEC compared with control subjects. Plasma ammonia concentrations were elevated on day 3 (mean +/- SE, 72 +/- 3.3 mumol/L) and decreased with postnatal age (p < 0.001) and increasing plasma arginine concentrations (p < 0.001). CONCLUSION: Plasma arginine concentrations are decreased at the time of diagnosis in premature infants with NEC. The potential benefit of arginine supplementation in the prevention of the disease deserves evaluation.

Age Factors↗
PubMed1997

Factors influencing the estimation of the albumin excretion rate in subjects with diabetes mellitus.

OBJECTIVE: To evaluate alternative methods of calculating the albumin excretion rate (AER) in the absence of complete and accurate patient documentation, since microalbuminuria in patients with diabetes mellitus is associated with serious complications and since patients often make errors in recording the volume and timing of urine collection, making AER calculations inaccurate. DESIGN: Prospective study. SETTING: Recruitment sites, including all native reserves, across southern Alberta. PARTICIPANTS: Population-based group of 1286 subjects with diabetes mellitus participating in the Southern Alberta Study of Diabetic Retinopathy. INTERVENTIONS: Timed AERs were measured in the subjects; urinary albumin concentration was measured by radioimmunoassay. OUTCOME MEASURES: A formula for the prediction of AER was based on the clinical data from the subjects. Several factors were considered in developing the formula: insulin-using status, weight, sex and urine and serum creatinine concentrations. RESULTS: A mathematical model for estimation of the AER was developed; incorporation of insulin use, sex and weight provides a more accurate estimate of AER. According to this model, women typically appear to have a lower AER than men and heavier people appear to have a higher AER than people with lower body weight. CONCLUSIONS: The use of mathematical formulae to calculate the AER provides an accurate estimate of the AER, particularly when data related to the volume and timing of urine collection are missing. These formulae will be valuable in large epidemiologic screening programs.

Alberta↗
PubMed1996

Appropriateness of plane pressure-sensitive film calibration for contact stress measurements in articular joints.

OBJECTIVE: To examine how accurately calibration stains from pressure-sensitive film samples compressed between perfectly flat surfaces represent contact pressures measured with the film inserted between curved joint surfaces. DESIGN: Experimental study. BACKGROUND: Contact pressure distributions and areas in joints are often quantified using pressure-sensitive film inserted between the articular surfaces. Absolute pressure values are recovered from the film through a calibration procedure. Since the calibration is typically performed in a different environment from the experimental measurements, a systematic error in the pressure magnitudes may be introduced. METHODS: Calibration stains were produced with an Instron machine using a flat and a slightly curved indenter. Calibration curves were fitted to the raw data of both indenters using a model representing the functional characteristics of the pressure-sensitive film. RESULTS: No systematic differences between the calibration curves from the flat and the curved indenter were observed. CONCLUSIONS: It appears that calibration with the film in a flat configuration is adequate for contact pressure measurements between moderately curved articular surfaces.

Journal Article↗
PubMed1995

Azathioprine and 6-mercaptopurine in Crohn disease. A meta-analysis.

PURPOSE: To assess the effectiveness of azathioprine and 6-mercaptopurine in inducing remission of active Crohn disease and the effectiveness of azathioprine in maintaining remission of quiescent disease. DATA SOURCES: Pertinent studies were selected from the MEDLINE database (1966 to May 1994), abstracts from major gastrointestinal meetings, and references from published articles and reviews. STUDY SELECTION: Nine randomized, placebo-controlled trials of azathioprine or 6-mercaptopurine therapy were identified: Four addressed active disease, two addressed quiescent disease, and three had multiple therapeutic arms. DATA EXTRACTION: Data were extracted by three independent observers on the basis of the intention-to-treat principle and were analyzed with logistic regression. Each study was given a quality score on the basis of predetermined criteria. DATA SYNTHESIS: Compared with placebo, azathioprine or 6-mercaptopurine therapy had an odds ratio of response of 3.09 (95% CI, 2.45 to 3.91) in patients with active Crohn disease. When the single trial that used 6-mercaptopurine in active disease was excluded from the analysis, the odds ratio of response was 1.45 (CI, 1.12 to 1.87). No trials of quiescent disease used 6-mercaptopurine; the odds ratio of response in these trials of quiescent disease was 2.27 (CI, 1.76 to 2.93). For active disease, continuation of therapy for at least 17 weeks improved response (P = 0.03). For quiescent disease, a higher dose improved response (P = 0.008). Increased cumulative dose improved response in both groups (P < 0.001 for active disease and P = 0.01 for quiescent disease). A steroid-sparing effect was seen in active disease (odds ratio, 3.69 (CI, 2.12 to 6.42) and in quiescent disease (odds ratio, 4.64 [CI, 1.00 to 21.54]). Fistulae improved with therapy (odds ratio, 4.44 [CI, 1.50 to 13.20]). Adverse events requiring withdrawal from a trial, primarily allergy, leukopenia, pancreatitis, and nausea, were increased with therapy (odds ratio, 5.26 [CI, 2.20 to 12.60]). CONCLUSIONS: Azathioprine and 6-mercaptopurine are effective in treating active Crohn disease and in maintaining remission. Cumulative dose was an important factor in predicting response. Adverse effects were more common among patients receiving therapy.

Azathioprine↗
PubMed1995

Influence of undergraduate and postgraduate education on recruitment and retention of physicians in rural Alberta.

The composition of practising physicians in Alberta, with respect to medical school of graduation, changed between 1986 and 1991. The percentage of graduates of the 2 Alberta medical schools increased, and the percentage of graduates of foreign medical schools decreased. Graduates of the University of Calgary increased their percentage in family practice in urban and rural communities except in Edmonton, while graduates of the University of Alberta increased their percentage almost everywhere except in communities with populations of < 4,000. Although graduates of Alberta medical schools are locating their practices in rural regions, the smaller communities continue to depend on foreign medical graduates. Retention is a problem in communities of < 4,000, with greatest mobility demonstrated by non-Albertan Canadian graduates and foreign medical graduates while Alberta graduates demonstrate less mobility. Overall, 85% of new Alberta physicians have had undergraduate or postgraduate experience in Alberta or Canada. Those with no medical educational experiences in Canada are more likely to locate in small communities. Those with postgraduate training in Alberta or Canada are more likely to locate in urban centres. When both undergraduate and postgraduate influences are considered, Alberta graduates appear to locate in non-urban regions to a greater extent than other Canadian or foreign graduates. For family physicians and specialists, the city where postgraduate training was obtained has a profound influence on the choice of urban practice locations.

Alberta↗
PubMed1994

The effect of 25 grams i.v. glucose on serum inorganic phosphate levels.

STUDY OBJECTIVE: To determine whether a 25-g IV glucose bolus will result in a fall in serum inorganic phosphate levels. DESIGN: Single-blind, randomized, controlled trial. PARTICIPANTS: Thirty-six healthy, nondiabetic, adult volunteers. INTERVENTIONS: Random allocation to a control group receiving a 50-mL normal saline bolus followed by a normal saline infusion at 125 mL/hr for three hours; study group 1, receiving a 50-mL bolus of D50W followed by a normal saline infusion at 125 mL/hr for three hours; or study group 2, receiving a 50-mL bolus of D50W followed by an infusion of 2/3:1/3 dextrose:saline solution at 125 mL/hr for three hours. MEASUREMENTS AND MAIN RESULTS: Serum inorganic phosphate levels were measured at time zero (baseline) and at 30-minute intervals for three hours. There was a statistically significant fall in serum inorganic phosphate levels in both groups receiving the glucose bolus. The group receiving the glucose infusion demonstrated a trend toward a further decline in serum phosphate levels. CONCLUSION: A glucose bolus and infusion in the amounts compatible with what is given to patients with altered levels of consciousness produced a significant fall in serum inorganic phosphate levels in healthy, nondiabetic adults. Because hypophosphatemia may create a clinical picture of altered mental status very similar to that of hypoglycemia, consideration should be given to administering IV glucose only to patients with finger-stick-proven hypoglycemia. Consideration also should be given to monitoring phosphate levels after administration of IV glucose.

Adult↗
PubMed1994

The effect of semirigid dressings on below-knee amputations.

BACKGROUND AND PURPOSE: The effect of using semirigid dressings (SRDs) on the residual limb of individuals who have had below-knee amputations as a consequence of peripheral vascular disease was investigated, with the primary question being: Does the time to readiness for prosthetic fitting for patients treated with the SRDs differ from that of patients treated with soft dressings? SUBJECTS: Forty patients entered the study and were alternately assigned to one of two groups. Nineteen patients were assigned to the SRD group, and 21 patients were assigned to the soft dressing group. METHODS: The time from surgery to readiness for prosthetic fitting was recorded for each patient. Kaplan-Meier survival curves were generated for each group, and the results were analyzed with the log-rank test. RESULTS: There was a difference between the two curves, and an examination of the curves suggests that the expected time to readiness for prosthetic fitting for patients treated with the SRDs would be less than half that of patients treated with soft dressings. CONCLUSION AND DISCUSSION: The results suggest that a patient may be ready for prosthetic fitting sooner if treated with SRDs instead of soft dressings.

Aged↗