Omitting pre-operative coagulation screening tests in hip fracture patients: stopping the financial cascade?

BACKGROUND

Coagulation screening continues as a standard of care in many hip fracture pathways despite the 2011 guidelines from the Association of Anaesthetists of Great Britain and Ireland (AAGBI) which recommend that such screening be performed only if clinically indicated. This study aims to evaluate the use of pre-operative coagulation screening and explore its financial impact.

METHODS

Prospective data was collected in accordance with the "Standardised Audit of Hip Fractures in Europe" (SAHFE) protocol. All patients admitted to our hospital with hip fractures during a 12-month period from November 2011 to November 2012 were analysed. Data including coagulation results and the use of vitamin K or blood products were collected retrospectively from the hospital computer system. Patient subgroup analysis was performed for intraoperative blood loss, post-operative blood units transfused, haematoma formation and gastrointestinal haemorrhage.

RESULTS

814 hip fractures were analysed. 91.4% (n=744) had coagulation tests performed and 22.0% (n=164) had an abnormal result. Of these, 55 patients were taking warfarin leaving 109 patients who had abnormal results and were not taking warfarin. When this group (n=109) was compared to those who had normal test results (n=580) and to all other patients (n=705) there was no difference in intraoperative blood loss (p=0.79, 0.78), postoperative transfusion (p=0.38, 0.30), postoperative haematoma formation (p=0.79, 1.00), or gastrointestinal haemorrhage (p=0.45, 1.00), respectively. In those who were not taking warfarin, but had abnormal results, none had treatment to reverse their coagulopathy with either vitamin K or blood products. By omitting pre-operative coagulation tests in patients who are not taking warfarin, we estimate a financial saving of between £66,500 and £432,250 per annum.

CONCLUSIONS

This study supports the hypothesis that routine pre-operative coagulation screening is unnecessary in hip fracture patients unless they take warfarin or have a known coagulopathy. Moreover, its omission represents significant cost-saving potential.

The impact factor of a journal is a poor measure of the clinical relevance of its papers

We evaluated the top 13 journals in trauma and orthopaedics by impact factor and looked at the longer-term effect regarding citations of their papers. All 4951 papers published in these journals during 2007 and 2008 were reviewed and categorised by their type, subspecialty and super-specialty. All citations indexed through Google Scholar were reviewed to establish the rate of citation per paper at two, four and five years post-publication. The top five journals published a total of 1986 papers. Only three (0.15%) were on operative orthopaedic surgery and none were on trauma. Most (n = 1084, 54.5%) were about experimental basic science. Surgical papers had a lower rate of citation (2.18) at two years than basic science or clinical medical papers (4.68). However, by four years the rates were similar (26.57 for surgery, 30.35 for basic science/medical), which suggests that there is a considerable time lag before clinical surgical research has an impact. We conclude that high impact journals do not address clinical research in surgery and when they do, there is a delay before such papers are cited. We suggest that a rate of citation at five years post-publication might be a more appropriate indicator of importance for papers in our specialty.

Extravasation injuries in adults

Insertion of an intravascular catheter is one of the most common invasive procedures in hospitals worldwide. These intravascular lines are crucial in resuscitation, allow vital medication to be administered, and can be used to monitor the patients' real-time vital parameters. There is, however, growing recognition of potential risks to life and limb associated with their use. Medical literature is now replete with isolated case reports of complications succinctly described by Garden and Laussen (2004) as "An unending supply of "unusual" complications from central venous catheters." This paper reviews complications of venous and arterial catheters and discusses treatment approaches and methods to prevent complications, based on current evidence and endeavours to provide information and guidance that will enable practitioners to prevent, recognise, and successfully treat extravasation injuries in adults.

Identification of residues in the carboxy-terminal domain of Clostridium perfringens alpha-toxin (phospholipase C) which are required for its biological activities

A panel of random mutants within the DNA encoding the carboxy-terminal domain of Clostridium perfringens alpha-toxin was constructed. Three mutants were identified which encoded alpha-toxin variants (Lys330Glu, Asp305Gly, and Asp293Ser) with reduced hemolytic activity. These variants also had diminished phospholipase C activity toward aggregated egg yolk phospholipid and reduced cytotoxic and myotoxic activities. Asp305Gly showed a significantly increased enzymatic activity toward the monodisperse substrate rhoNPPC, whereas Asp293Ser displayed a reduced activity toward this phospholipid analogue. In addition, Asp293Ser showed an increased dependence on calcium for enzymatic activity toward aggregated phospholipid and appeared calcium-depleted in PAGE band-shift assays. In contrast, neither Lys330Glu nor Asp305Gly showed altered dependence on calcium for enzymatic activity toward aggregated phospholipid. Asp305 is located in the interface between the amino- and carboxy-terminal domains, whereas Asp293 and Lys330 are surface exposed residues which may play a role in the recognition of membrane phospholipids.

Fermentation, purification, and efficacy of a recombinant vaccine candidate against botulinum neurotoxin type F from Pichia pastoris

A recombinant vaccine candidate was developed that protected mice against botulinum neurotoxin serotype F (BoNTF) intoxication. A synthetic gene encoding BoNTF fragment C (rBoNTF(H(c))) was designed, constructed, and inserted into a plasmid for expression in the yeast Pichia pastoris. A total cell protein content of 2.9 g was obtained per liter of fermentation broth. Recombinant rBoNTF(H(c)) was purified from the soluble yeast extract in two chromatographic steps. The process employed Mono S cation exchange chemistry followed by Alkyl-Superose hydrophobic interaction chromatography, producing material judged to be greater than 98% pure by SDS-PAGE. The recovery of purified product from cell extract was estimated to be greater than 42%, with a yield of 140 mg/kg of cell paste. rBoNTF(H(c)) was also purified from the insoluble fraction of the yeast cell lysate. Because the fragment C in the pellet was 35% of the total insoluble protein, only a Mono S cation exchange chromatography step was necessary to achieve a purity greater than 98%. Mice that received three injections of 0.2 microgram of purified soluble rBoNTF(H(c)) were completely protected when challenged with 1000 mouse ip LD(50) of BoNTF toxin. Similarly, three doses of 1 microgram of purified resolubilized rBoNTF(H(c)) completely protected mice from a challenge of 5000 mouse ip LD(50) of BoNTF toxin. Individual serum antibody ELISA titers of mice injected with soluble rBoNTF(H(c)) correlated with survival as all 34 mice with ELISA titers of 100 or greater survived toxin challenge. The work presented here demonstrates that purified rBoNTF(H(c)) is able to protect against a high challenge dose of neurotoxin.

Differences in the carboxy-terminal (Putative phospholipid binding) domains of Clostridium perfringens and Clostridium bifermentans phospholipases C influence the hemolytic and lethal properties of these enzymes

The phospholipases C of C. perfringens (alpha-toxin) and C. bifermentans (Cbp) show >50% amino acid homology but differ in their hemolytic and toxic properties. We report here the purification and characterisation of alpha-toxin and Cbp. The phospholipase C activity of alpha-toxin and Cbp was similar when tested with phosphatidylcholine in egg yolk or in liposomes. However, the hemolytic activity of alpha-toxin was more than 100-fold that of Cbp. To investigate whether differences in the carboxy-terminal domains of these proteins were responsible for differences in the hemolytic and toxic properties, a hybrid protein (NbiCalpha) was constructed comprising the N domain of Cbp and the C domain of alpha-toxin. The hemolytic activity of NbiCalpha was 10-fold that of Cbp, and the hybrid enzyme was toxic. These results confirm that the C-terminal domain of these proteins confers different properties on the enzymatically active N-terminal domain of these proteins.

A randomized trial of Staphylococcus aureus prophylaxis in peritoneal dialysis patients: mupirocin calcium ointment 2% applied to the exit site versus cyclic oral rifampin

The objective of this study was to compare prophylaxis for Staphylococcus aureus infections in peritoneal dialysis patients using 600 mg cyclic oral rifampin for 5 days every 3 months versus mupirocin calcium ointment 2% applied daily to the exit site. The study design was a prospective randomized trial, controlling for S aureus nasal carriage. Eighty-two continuous ambulatory and continuous cyclic peritoneal dialysis patients (54% male, 71 % white, 34% insulin-dependent, mean prestudy time on peritoneal dialysis 1.2 years) were randomly assigned to cyclic rifampin (n = 41 patients) or daily exit site mupirocin prophylaxis (n = 41 patients). Mean follow-up was 1 year. S aureus catheter infection rates were 0.13/yr with mupirocin and 0.15/yr with rifampin (P = NS). Both rates were significantly lower than the center's historical rate (the period between 1983 and 1992) of 0.46/yr prior to the study (P < 0.001). S aureus peritonitis rates were 0.04/yr with mupirocin and 0.02/yr with rifampin (P = NS), both significantly lower than the center's historical rate of 0.16/yr (P < 0.02). Catheter loss due to S aureus infections was 0.02/yr with mupirocin and 0/yr with rifampin (P = NS), both significantly lower than the center's historical rate of 0.12/yr (P < 0.001). There were no side effects in patients using mupirocin, but 12% were unable to continue rifampin due to side effects. We conclude that mupirocin ointment at the exit site and cyclic oral rifampin are equally effective in reducing S aureus catheter infections. In addition, rifampin or mupirocin significantly reduced S aureus peritonitis and catheter loss due to S aureus infections. Mupirocin at the exit site provides an excellent alternative prophylaxis for S aureus infections, particularly in patients who cannot tolerate oral rifampin therapy.

Immunolocalization of matrix metalloproteinases and TIMP-1 (tissue inhibitor of metalloproteinases) in human gingival tissues from periodontitis patients

The matrix metalloproteinases (MMPs) collagenase, gelatinase A (72 kDa gelatinase), stromelysin, and their specific inhibitor TIMP-1 (tissue inhibitor of metalloproteinases), were immunolocalized using specific polyclonal antisera in gingival tissues from 21 patients with chronic inflammatory periodontal disease. Monoclonal antibodies against macrophages (Leu-M5), B cells (Leu-14), helper T cells (OKT4), suppressor T cells (OKT8) and the HLA-DR epitope were also used to identify leukocyte subsets. MMPs were observed in connective tissues at sites that histologically showed signs of remodelling. The number and distribution of positive cells varied widely, however, not only between individual biopsy specimens, but also within the same specimen. The same was true for the composition and distribution of the inflammatory cell infiltrate. Moreover, although there was a positive correlation between the number of MMP-producing cells and the severity of inflammation in some specimens, for others with comparable leukocyte subset scoring the number was reduced and sometimes absent altogether. Cells secreting MMPs were fibroblasts, macrophages and epithelial cells. It was not possible to determine unequivocally whether a MMP-positive cell within the connective tissue was a fibroblast or a macrophage, since the antisera recognise both fibroblast and macrophage MMPs and the different fixation requirements for MMPs (4% paraformaldehyde) and Leu-M5 (acetone) precluded co-localization on the same section. TIMP-1 was immunolocalized within connective tissue cells at sites of tissue remodelling. Our results support the hypothesis that tissue-derived MMPs may be involved in tissue remodelling in periodontal disease and conclusively demonstrate that epithelial cells may be involved as well as connective tissue cells.

Uptake and cytotoxicity of novel nitroimidazole-polyamine conjugates in Ehrlich ascites tumour cells

A number of tumour cells, including Ehrlich ascites tumour cells (EATC), possess a polyamine uptake system which selectively accumulates endogenous polyamines and structurally related compounds by an active energy dependent system(s). We suggest that it may be possible to utilize this uptake system to target certain cytotoxic agents to those tumour cells possessing this system. In an initial attempt to determine the feasibility of this suggestion, we have synthesized a series of 2- and 5-nitroimidazoles linked to polyamines and determined their ability to utilize the polyamine uptake system. Within the limited series of compounds synthesized, 2-nitroimidazole-polyamine conjugates were more potent inhibitors of spermidine uptake into EATC than the 5-nitroimidazole conjugates. It has been assumed partly based on the competitive nature of this inhibition, that the ability of these compounds to inhibit spermidine uptake is also a measure of their ability to be accumulated by EATC. A greater than 700-fold variation was observed in the ability of different analogues to inhibit spermidine uptake. The most potent inhibitors retained certain structural characteristics similar to those of spermidine. Those compounds linked to polyamines were much more potent inhibitors of polyamine uptake than the parent nitroimidazoles i.e. metronidazole and misonidazole. The toxicity of the parent compounds and their polyamine conjugates in control and polyamine-depleted EATC was assessed by measuring inhibition of tritiated thymidine incorporation. Polyamine depletion, by prior exposure to difluoromethylornithine, results in a compensatory increase in the uptake of polyamines and related structures which may result in an increase in toxicity. Whilst many of the novel conjugates showed only little or moderate toxicity to control cells, the toxicity of several of the conjugates but not the parent nitroimidazoles increased in the polyamine-depleted cells. A clear distinction was also observed between the ability to inhibit spermidine uptake (and hence affinity for the uptake system) and toxicity, e.g. compound 430, a dinitroimidazole-polyamine conjugate, was the best inhibitor of spermidine uptake studied but showed no toxicity. These results support the hypothesis that linking polyamines to nitroimidazoles facilitates the entry of the latter into cells, such as EATC, which possess the polyamine uptake system and may therefore have therapeutic application in the delivery of polyamine-linked cytotoxics to certain tumours.

Calcium mass transfer in peritoneal dialysis patients using 2.5 mEq/l calcium dialysate

Standard peritoneal dialysate has a relatively high calcium concentration of 3.5 mEq/l. Peritoneal dialysis patients thus gain calcium from the dialysate which contributes to the risk of hypercalcemia. Dialysate with 2.5 mEq/l calcium is now available. Theoretically, using dialysate with this calcium content, calcium transfer should be negative (from the patient into the dialysate) when the patient is hypercalcemic, and positive when the patient is normocalcemic or hypercalcemic. Thus, 2.5 mEq/l calcium dialysate may allow larger doses of calcium carbonate to be prescribed. We compared calcium mass transfer (CMT) in 17 stable peritoneal dialysis patients using 3.5 and 2.5 mEq/l calcium dialysate. A solution of 2.05 l, 1.5 g/dl dextrose was dwelled for 4 hours. Calcium was measured in the drained dialysate and serum (total and ionized). Mean CMT was 0.7 +/- 0.5 mEq/exchange using 3.5 mEq/l calcium dialysate and -0.9 +/- 0.9 mEq/exchange using 2.5 mEq/l calcium dialysate (p less than 0.0001). At the time of the CMT studies, the mean serum ionized calcium levels were identical for the two groups (2.6 mEq/l). CMT correlated inversely with serum total calcium, serum ionized calcium, and drained dialysate volume. During hypercalcemia calcium transfer was from the dialysate to the patient when 3.5 mEq/l calcium dialysate was used, but from the patient to the dialysate when 2.5 mEq/l calcium dialysate was used. We conclude that 2.5 mEq/l calcium dialysate is effective in removing calcium and will be helpful in preventing hypercalcemia when large doses of oral calcium compounds are prescribed as a phosphate binder.

Airway management in patients with unstable cervical spine fractures

We conducted a retrospective study of traumatic, unstable cervical spine fractures requiring operative repair to determine the airway management technique and whether any neurologic complication resulted from the intubation. One hundred thirty-three patients with 140 fractures were reviewed relative to fracture site, oral versus nasal route of intubation, and location of intubation (surgery versus emergency department or field). Fracture site incidence was determined as follows: C-1, ten (7.1%); odontoid/C-2, 17 (12.1%); C-3, eight (5.7%); C-4, 21 (15.0%); C-5, 41 (29.2%); C-6, 38 (27.1%); and C-7, five (3.5%). Ten of the injuries resulted from blows to the neck or head, 25 from falls, seven from diving, and six from sports-related injuries. The remaining eighty-five patients were in motor vehicle accidents. Nine patients were nasally intubated in the ED, and one patient was orally intubated in the field. Ninety-four of the patients intubated in surgery were intubated nasally: 29 were intubated orally while in-line stabilization was maintained. No neurologic complications occurred in any patient. These data suggest that, under controlled circumstances, patients with unstable cervical spine fractures can be safely intubated with standard, nonsurgical approaches.

Treatment of high blood pressure in the young

Children with high normal or high BP should also be evaluated for other cardiovascular risk factors, and interventions should address overall cardiovascular risk. Nonpharmacologic interventions include weight reduction when appropriate, avoidance of dietary salt excess, and dynamic exercise. Drug treatment should be required in a minority of children with hypertension. There are concerns about the longterm effects of drug therapy on lipid and carbohydrate metabolism and on physical and cognitive growth and development. Beta adrenergic antagonists and diuretics are usually the first line drugs to be added to the nonpharmacologic therapeutic strategies for BP control in children. After a sufficient period of BP control, a stepped-down approach and discontinuation of drug therapy should be considered.

Effects of vitamin B6 nutritional status on the uptake of [3H]-oestradiol into the uterus, liver and hypothalamus of the rat

Rats were depleted of vitamin B6 by treatment with isoniazid, and then maintained on diets providing: no vitamin B6, an adequate amount (1.2 mg/kg diet) or a very large amount (120 mg/kg) for 5 weeks. The uptake of a tracer dose of [3H]-oestradiol into the nuclei of liver and uterus was significantly greater in deficient animals than in those receiving an adequate or greater than adequate amount of the vitamin. Similarly the accumulation of oestradiol in the region of the brain corresponding to the hypothalamus, pre-optic area and septum (the major oestradiol-sensitive regions of the central nervous system) was higher in deficient animals than in other groups. There were significant inverse correlations between the uptake of oestradiol into target tissues and vitamin B6 nutritional status as determined by the concentrations of pyridoxal phosphate in plasma and liver. Uteri from deficient animals were significantly smaller than those from animals receiving an adequate or greater amount of vitamin B6, and the induction of uterine peroxidase by oestradiol was impaired. It therefore seems likely that despite the greater net accumulation of steroid in target tissues, vitamin B6 deficiency impairs biological responsiveness to oestrogens. It is suggested that this may be due to a failure of the recycling of oestradiol receptors from the nucleus.