Blood transfusions in total knee arthroplasty: a retrospective analysis of a multimodal patient blood management programme.

PURPOSE: Transfusion is associated with increased perioperative morbidity and mortality in patients undergoing total knee arthroplasty (TKA). Patient blood management (PBM) is an evidence-based approach to maintain blood mass via haemoglobin maintenance, haemostasis optimisation, and blood loss minimisation. The aim of the present study was to assess the effectiveness of a multimodal PBM approach in our centre. METHODS: This was a single-centre retrospective study of patients who underwent primary TKA in Queen Mary Hospital in Hong Kong in 2013 or 2018, using data from the Clinical Data Analysis and Reporting System and a local joint registry database. Patient demographics, preoperative haemoglobin, length of stay, readmission, mean units of transfusion, postoperative prosthetic joint infection, and mortality data were compared between groups. RESULTS: In total, 262 and 215 patients underwent primary TKA in 2013 and 2018, respectively. The mean transfusion rate significantly decreased after PBM implementation (2013: 31.3%; 2018: 1.9%, P<0.001); length of stay after TKA also significantly decreased (2013: 14.49±8.10 days; 2018: 8.77±10.14 days, P<0.001). However, there were no statistically significant differences in readmission, early prosthetic joint infection, or 90-day mortality rates between the two groups. CONCLUSION: Our PBM programme effectively reduced the allogeneic blood transfusion rate in patients undergoing TKA in our institution. Thus, PBM should be considered in current TKA protocols to reduce rates of transfusions and related complications.

Anaerobic digestion of chemically enhanced primary treatment (CEPT) sludge and the microbial community structure.

The effectiveness and treatment conditions of FeCl3- and AlCl3-coagulated municipal sewage sludge from chemically enhanced primary treatment (CEPT) using anaerobic digestion (AD) and the structure of microbial community were investigated. The results based on 297 measurements under different operational conditions demonstrate good average AD performance of CEPT sludge, that is, percent volatile solid reduction of 58 %, specific biogas production (or biogas yield) of 0.92 m(3)/kg volatile solids (VS) destroyed, and methane content of 65.4 %. FeCl3 dosing, organic loading rate, temperature, and hydraulic retention time all significantly affected AD performance. FeCl3 dosing greatly improved specific methane production (methane yield) by 38-54 % and significantly reduced hydrogen sulfide (H2S) content in biogas (from up to 13,250 to <200 ppm), contributing to higher methane recovery and simplified biogas cleaning for power generation. Metagenomic analysis suggested that anaerobic digesters of both CEPT sludge and combined primary and secondary sludge were dominated by Bacteroidetes, Proteobacteria, Firmicutes, Actinobacteria, Thermotogae, and Chloroflexi. However, Methanomicrobia methanogens were better enriched in the anaerobic digesters of CEPT sludge than in the combined sludge. Further, different sources of CEPT sludge with various chemical properties nurtured shared and unique microbial community composition. Combined, this study supports AD as an efficient technology for CEPT sludge treatment and poses first insights into the microbial community structure.

Pilot trial study of a compact macro-filtration membrane bioreactor process for saline wastewater treatment.

Conventional membrane bioreactor (MBR) systems have increasingly been studied in recent decades. However, their applications have been limited due to their drawbacks such as low flux, membrane fouling, and high operating cost. In this study, a compact macro-filtration MBR (MfMBR) process was developed by using a large pore size membrane to mitigate the membrane fouling problem. A pilot trial of MfMBR process was set up and operated to treat 10 m(3)/day of saline wastewater within 4 h. The system was operated under an average permeate flux of 13.1 m(3)/(m(2)·day) for 74 days. The average total suspended solids, total chemical oxygen demand, biological oxygen demand, total Kjeldahl nitrogen, and total nitrogen removal efficiencies achieved were 94.3, 83.1, 98.0, 93.1, and 63.3%, respectively, during steady-state operation. The confocal laser scanning microscopy image indicated that the backwash could effectively remove the bio-cake and dead bacteria. Thus, the results showed that the MfMBR process, which is essentially a primary wastewater treatment process, had the potential to yield the same high quality effluent standards as the secondary treatment process; thereby suggesting that it could be used as an option when the economic budget and/or land space is limited.

Quantitative test of knee laxity in Chinese.

Anterior knee laxity of 100 Chinese male subjects who had no history of previous injuries to their knees was examined with an instrumented knee arthrometer (MEDmetric Knee Arthrometer, model KT-1000). Two measurements were used to evaluate the anterior laxity: 1) anterior displacement produced by anterior force of 89 newtons (20 lbs); and 2) anterior compliance index (ACI), the displacement difference between an anterior force of 89 newtons (20 lbs) and 67 newtons (15 lbs). All knees were examined at a flexion angle of 20 +/- 5 degrees and an external tibial rotation of 10 +/- 5 degrees with the use of thigh and foot supports. The mean anterior displacement for the right and left knee were 4.5 +/- 2.0 mm and 4.3 +/- 1.9 mm, respectively, while 84% of the study subjects had right and left differences (anterior displacement difference, ADD) of less than 2 mm. The anterior compliance index was 0.85 +/- 0.4 mm for the right knee and 0.78 +/- 0.33 mm for the left knee. The mean anterior compliance index difference (CID), that is the difference between the right and left ACI, was 0.25 +/- 0.3 mm. A total of 93% of the subjects had a difference in the right-left CID of less than 0.5 mm. Variation between the right and left knee does exist, but the difference is not statistically significant (p > 0.05). Therefore, comparison of the right-left ADD and CID can be a useful reference in the assessment of a ligamentous injury.

Differentiation of angiotensin-converting enzyme (ACE) inhibitors by their selective inhibition of ACE in physiologically important target organs.

Seven ACE inhibitors were studied for possible differences in distribution to aorta, brain, heart, lung, and kidney after administration of single oral doses to spontaneously hypertensive rats (SHR). Doses, normalized for differences in inhibitory potency and molecular weight, were expected to deliver equivalent levels of ACE-inhibitory activity to the circulation, and this was confirmed by preliminary dose-response studies. The relative potencies of the active moieties of the seven drugs and the normalized oral doses used were: SQ 29,852 (1.0), 100 mg/kg; captopril (3.5), 30 mg/kg; enalapril (12), 20 mg/kg; fosinopril (13), 25 mg/kg; zofenopril (20), 10 mg/kg; lisinopril (24), 10 mg/kg; and ramipril (51), 5 mg/kg. In these ex vivo studies, ACE activities were determined fluorometrically in SHR sera and in uncentrifuged homogenates of the solid tissues at various times after oral dosing with the ACE inhibitors. As expected, the normalized oral doses of the seven inhibitors had equivalent effects on serum ACE. In lung, where ACE has a vascular endothelial localization, and in aorta, where ACE inhibition correlates with antihypertensive action, ramipril, lisinopril, and zofenopril were distinguished by the magnitude and duration (three to four days) of their effects. In the brain, where ACE may affect central regulation of blood pressure and participate in the degradation of certain neuropeptides, ramipril and enalapril had no effect; captopril and zofenopril had modest, short-lasting effects, and fosinopril, lisinopril, and SQ 29,852 had delayed but long-lasting inhibitory actions. In the kidney, where ACE inhibition may have positive or negative effects on renal function, ramipril and fosinopril could be distinguished by their weak actions, perhaps associated with biliary routes of excretion. In the heart, where ACE inhibitors may prevent ischemic damage to the myocardium, single oral doses of captopril, fosinopril, and particularly zofenopril produced striking and long-lasting inhibition, whereas equivalent doses of ramipril and enalapril produced barely detectable inhibition.

Comparisons in vitro, ex vivo, and in vivo of the actions of seven structurally diverse inhibitors of angiotensin converting enzyme (ACE).

1. Seven drugs (captopril, zofenopril, enalapril, ramipril, lisinopril, fosinopril, and SQ 29,852) were compared in vitro in homogenates of aorta, brain, heart, lung, and kidney and in sera of spontaneously hypertensive rats (SHR) both with respect to potencies of their active moieties as inhibitors of angiotensin-converting enzyme (ACE), and, where applicable, rates of hydrolysis of their prodrug ester functions. 2. In ex vivo dose-response and time-course studies, the inhibitory effects of the seven drugs on tissue ACEs and their relative distributions to SHR tissues were compared following oral administration. 3. The relative potencies of the inhibitory moieties of the drugs (in parentheses) and the normalized 'equiactive' oral doses employed for time-course studies were: SQ 29,852 (1.0), 100 mg kg-1; captopril (3.5), 30 mg kg-1; enalapril (12), 20 mg kg-1; fosinopril (13), 25 mg kg-1; zofenopril (20), 10 mg kg-1; lisinopril (24), 10 mg kg-1; and ramipril (51), 5 mg kg-1. 4. Following oral administration of the drugs to SHR, the degree and duration of ACE inhibition in aorta and lung correlated with the antihypertensive actions, with ramipril, lisinopril, and zofenopril producing effects of the greatest magnitude and duration. 5. Ramipril and enalapril did not inhibit brain ACE ex vivo; captopril and zofenopril had modest but short-lasting effects; and fosinopril, lisinopril, and SQ 29,852 had long-lasting inhibitory actions, which, with the latter two, were delayed in onset. 6. All of the drugs produced significant inhibition of kidney ACE, with ramipril and fosinopril having somewhat weaker effects, perhaps due to biliary routes of excretion. 7. Captopril, fosinopril, and particularly zofenopril inhibited cardiac ACE ex vivo with degrees and durations that were marked compared with those of the other drugs; preliminary studies with isolated hearts suggest a possible relationship between inhibition of cardiac ACE and preservation of cardiac function subsequent to ischaemia.