The relation between acute changes in the systemic inflammatory response and circulating thiamine and magnesium concentrations after elective knee arthroplasty.

Thiamine diphosphate (TDP) and magnesium are co-factors for key enzymes in human intermediary metabolism. However, their role in the systemic inflammatory response (SIR) is not clear. Therefore, the aim of the present study was to examine the relation between acute changes in the SIR and thiamine and magnesium dependent enzyme activity in patients undergoing elective knee arthroplasty (a standard reproducible surgical injury in apparently healthy individuals). Patients (n = 35) who underwent elective total knee arthroplasty had venous blood samples collected pre- and post-operatively for 3 days, for measurement of whole blood TDP, serum and erythrocyte magnesium, erythrocyte transketolase activity (ETKA), lactate dehydrogenase (LDH), glucose and lactate concentrations. Pre-operatively, TDP concentrations, erythrocyte magnesium concentrations, ETKA and plasma glucose were within normal limits for all patients. In contrast, 5 patients (14%) had low serum magnesium concentrations (< 0.75 mmol/L). On post-operative day1, both TDP concentrations (p < 0.001) and basal ETKA (p < 0.05) increased and serum magnesium concentrations decreased (p < 0.001). Erythrocyte magnesium concentrations correlated with serum magnesium concentrations (rs = 0.338, p < 0.05) and remained constant during SIR. Post-operatively 14 patients (40%) had low serum magnesium concentrations. On day1 serum magnesium concentrations were directly associated with LDH (p < 0.05), WCC (p < 0.05) and neutrophils (p < 0.01). Whole blood TDP and basal ETKA increased while serum magnesium concentrations decreased, indicating increased requirement for thiamine and magnesium dependent enzyme activity during SIR. Therefore, thiamine and magnesium represent potentially modifiable therapeutic targets that may modulate the host inflammatory response. Erythrocyte magnesium concentrations are likely to be reliable measures of status, whereas serum magnesium concentrations and whole blood TDP may not.ClinicalTrials.gov: NCT03554668.

The relation between acute changes in the systemic inflammatory response and plasma 25-hydroxyvitamin D concentrations after elective knee arthroplasty.

BACKGROUND: Studies indicate that low plasma 25-hydroxyvitamin D [25(OH)D] is associated with a range of disease processes, many of which are inflammatory. However, other lipid-soluble vitamins decrease during the systemic inflammatory response, and this response may confound the interpretation of plasma 25(OH)D. OBJECTIVE: The objective was to examine whether plasma 25(OH)D concentrations change during evolution of the systemic inflammatory response. DESIGN: Patients (n = 33) who underwent primary knee arthroplasty had venous blood samples collected preoperatively and postoperatively (beginning 6-12 h after surgery and on each morning for 5 d) for the measurement of 25(OH) D, vitamin D-binding protein, parathyroid hormone (PTH), calcium, C-reactive protein, and albumin. A final sample was collected at 3 mo. RESULTS: Preoperatively, most patients were 25(OH)D deficient (<50 nmol/L) and had secondary hyperparathyroidism (PTH > 5 pmol/L). Age, sex, body mass index, season, medical history, and medication use were not associated with significant differences in preoperative plasma 25(OH)D concentrations. By day 2 there was a large increase in C-reactive protein concentrations (P < 0.001) and a significant decrease in 25(OH)D of ≈40% (P < 0.001). C-reactive protein, 25(OH)D, and calculated free 25(OH)D had not returned to preoperative concentrations by 5 d postoperatively (all P < 0.001). At 3 mo, 25(OH)D and free 25(OH)D remained significantly lower (20% and 30%, respectively; P < 0.01). CONCLUSION: Plasma concentrations of 25(OH)D decrease after an inflammatory insult and therefore are unlikely to be a reliable measure of 25(OH)D status in subjects with evidence of a significant systemic inflammatory response.

The effect of gender on postoperative mortality after emergency abdominal surgery.

BACKGROUND: The factors contributing to the high mortality after emergency abdominal surgery are unclear. Recent studies have revealed gender differences in immune function after trauma and in the presence of sepsis. OBJECTIVE: This study tested the hypothesis that factors determining survival after emergency abdominal surgery differ in males and females. METHODS: Consecutive patients, aged > or =50 years, who underwent emergency abdominal surgery between July 1998 and June 2000 at the Royal and Western Infirmaries in Glasgow, Scotland, were identified for study. Data collected retrospectively included sex, age, severity of surgery, seniority of surgeon and anesthetist, extent of deprivation, and 30-day postoperative mortality. RESULTS: A total of 633 patients were identified for study; 49 (8%) were excluded from analysis because 30-day mortality or surgery details were unavailable. Of the remaining 584 patients, 256 were male and 328 were female. The overall 30-day mortality was 26%, with 74 (29%) males and 79 (24%) females dying within this period. The mortality rates were 25% in males and 10% in females (P = 0.043) after minor surgery, 26% in males and 23% in females (P = NS) after intermediate surgery, and 44% in males and 39% in females (P = NS) after major surgery. On univariate logistic regression analysis in males, increasing age (P < 0.001), severity of surgery (P = 0.04), and seniority of anesthetist (P < 0.001) were associated with mortality. In females, severity of surgery (P < 0.001) was associated with mortality. CONCLUSIONS: These results show that in females, 30-day mortality was determined by severity of surgery, whereas in males increasing age and seniority of anesthetist also influenced 30-day mortality.

Normobaric hyperoxia reduces cardiac index in patients after coronary artery bypass surgery.

OBJECTIVE: The purpose of this study was to assess the hemodynamic changes in response to normobaric hyperoxia in patients immediately after coronary artery bypass surgery. DESIGN: Observational study. SETTING: Single-center university hospital. PARTICIPANTS: Patients immediately after coronary artery bypass surgery. INTERVENTION: Change of fractional inspired oxygen concentration from baseline (< or =0.60) to 1.0 and return to baseline. MEASUREMENTS AND MAIN RESULTS: Cardiovascular changes were assessed with a lithium dilution technique. Cardiac index decreased from 2.82 to 2.52 L/min/m2 (10.6%). Heart rate decreased from 85.9 to 82.5 beats/min (4.0%), and the systemic vascular resistance index increased from 1,858 to 2,304 dyne/s/cm5/m2 (24.1%). Stroke index or mean arterial pressure did not change significantly. On reducing the FIO2 from 1.0 to the baseline FIO2 , there was significant reversal of the previous changes in heart rate and systemic vascular resistance. Heart rate increased from 82.5 to 84.0 beats/min (1.8%), and the systemic vascular index decreased from 2304 to 1932 dyne/s/cm5/m2 (16.1%). The cardiac output did not return to baseline, and the mean arterial pressure decreased from 69.6 to 64.4 mmHg (7.6%). CONCLUSIONS: Exposing patients after coronary artery surgery to hyperoxia induces significant hemodynamic changes.