R. Griffiths

Outcome by mode of anaesthesia for hip fracture surgery. An observational audit of 65 535 patients in a national dataset

Large observational studies of accurate data can provide similar results to more arduous and expensive randomised controlled trials. In 2012, the National Hip Fracture Database extended its dataset to include ‘type of anaesthesia’ data fields. We analysed 65 535 patient record sets to determine differences in outcome. Type of anaesthesia was recorded in 59 191 (90%) patients. Omitting patients who received both general and spinal anaesthesia or in whom an uncertain type of anaesthesia was recorded, there was no significant difference in either cumulative five‐day (2.8% vs 2.8%, p = 0.991) or 30‐day (7.0% vs 7.5%, p = 0.053) mortality between 30 130 patients receiving general anaesthesia and 22 999 patients receiving spinal anaesthesia, even when 30‐day mortality was adjusted for age and ASA physical status (p = 0.226). Mortality within 24 hours after surgery was significantly higher among patients receiving cemented compared with uncemented hemiarthroplasty (1.6% vs 1.2%, p = 0.030), suggesting excess early mortality related to bone cement implantation syndrome. If these data are accurate, then either there is no difference in 30‐day mortality between general and spinal anaesthesia after hip fracture surgery per se, and therefore future research should focus on how to make both types of anaesthesia safer, or there is a difference, but mortality is not the correct outcome to measure after anaesthesia, and therefore future research should focus on differences between general and spinal anaesthesia. These could include more anaesthesia‐sensitive outcomes, such as hypotension, pain, postoperative confusion, respiratory infection and mobilisation.

Nottingham Hip Fracture Score: longitudinal and multi-centre assessment

BACKGROUND The Nottingham Hip Fracture Score (NHFS) was developed and validated in a single centre in 2007 as a predictor of 30 day mortality. It has subsequently been shown to predict longer term and functional outcomes. We wished to assess the ability of NHFS to predict outcomes in other centres and to investigate the change in outcome after hip fracture over time. METHODS The NHFS was calculated for all patients with data from three UK hip fracture units: Peterborough (1992-2009), Brighton (2008-9), and Nottingham (2000-9) including 4804, 585, and 1901 patients, respectively. The logistic regression was used to recalibrate the NHFS to 30 day mortality across the three units using a random selection of 50% of the data set. Calibration was assessed using the Hosmer-Lemeshow goodness of fit. RESULTS The median (inter-quartile range) NHFS values were Peterborough [4.0 (1-6)], Brighton [5.0 (3-7)], and Nottingham [5.0 (3-7)]. There was no correlation between 30 day mortality and time (R(2)=0.05, P=0.115). The proportion of patients with NHFS ≥ 4 showed a weak correlation with time (R(2)=0.2, P=0.003). The original NHFS equation overestimates mortality in the higher-risk groups. A modified equation shows good calibration for all three centres {30 day mortality (%)=100/1+e([(5.012 × (NHFS × 0.481)])}. The hospital was not a predictor of 30 day mortality. CONCLUSIONS The NHFS, with an updated equation, is a robust predictor of 30 day mortality after hip fracture repair in geographically distinct UK centres.

Secondary analysis of outcomes after 11,085 hip fracture operations from the prospective UK Anaesthesia Sprint Audit of Practice (ASAP-2)

We re‐analysed prospective data collected by anaesthetists in the Anaesthesia Sprint Audit of Practice (ASAP‐1) to describe associations with linked outcome data. Mortality was 165/11,085 (1.5%) 5 days and 563/11,085 (5.1%) 30 days after surgery and was not associated with anaesthetic technique (general vs. spinal, with or without peripheral nerve blockade). The risk of death increased as blood pressure fell: the odds ratio (95% CI) for mortality within five days after surgery was 0.983 (0.973–0.994) for each 5 mmHg intra‐operative increment in systolic blood pressure, p = 0.0016, and 0.980 (0.967–0.993) for each mmHg increment in mean pressure, p = 0.0039. The equivalent odds ratios (95% CI) for 30‐day mortality were 0.968 (0.951–0.985), p = 0.0003 and 0.976 (0.964–0.988), p = 0.0001, respectively. The lowest systolic blood pressure after intrathecal local anaesthetic relative to before induction was weakly correlated with a higher volume of subarachnoid bupivacaine: r2 −0.10 and −0.16 for hyperbaric and isobaric bupivacaine, respectively. A mean 20% relative fall in systolic blood pressure correlated with an administered volume of 1.44 ml hyperbaric bupivacaine. Future research should focus on refining standardised anaesthesia towards administering lower doses of spinal (and general) anaesthesia and maintaining normotension.

Safety guideline: reducing the risk from cemented hemiarthroplasty for hip fracture 2015: Association of Anaesthetists of Great Britain and Ireland British Orthopaedic Association British Geriatric Society.

Concise guidelines are presented for the preparation and conduct of anaesthesia and surgery in patients undergoing cemented hemiarthroplasty for hip fracture. The Working Party specifically considered recent publications highlighting complications occurring during the peri‐operative period . The advice presented is based on previously published advice and clinical studies.

Rheumatoid arthritis and anaesthesia.

There has been a great deal of progress in our understanding and management of rheumatoid arthritis in recent years. The peri‐operative management of rheumatoid arthritis patients can be challenging and anaesthetists need to be familiar with recent developments and potential risks of this multi system disease.

Prediction of 30-day mortality after hip fracture surgery by the Nottingham Hip Fracture Score and the Surgical Outcome Risk Tool

The care of the elderly with hip fractures and their outcomes might be improved with resources targeted by the accurate calculation of risks of mortality and morbidity. We used a multicentre national dataset to evaluate and recalibrate the Nottingham Hip Fracture Score and Surgical Outcome Risk Tool. We split 9,017 hip fracture cases from the Anaesthesia Sprint Audit of Practice into derivation and validation data sets and used logistic regression to derive new model co‐efficients for death at 30 postoperative days. The area (95% CI) under the receiver operator characteristic curve of 0.71 (0.67–0.75) indicated acceptable discrimination by the Nottingham Hip Fracture Score and acceptable calibration fit (Hosmer–Lemeshow test), p = 0.23, with a similar discrimination by the Surgical Outcome Risk Tool, 0.70 (0.66–0.74), which was miscalibrated to the observed data, p = 0.001. We recommend that studies test these scores for patients with hip fractures in other countries. We also recommend these models are compared with case‐mix adjustment tools used in the UK.

Bone cement implantation syndrome and proximal femoral fracture

The report from Olsen and colleagues on bone cement implantation syndrome (BCIS) in this edition of the British Journal of Anaesthesia coincides with the recent publication of the Anaesthesia Sprint Audit of Practice (ASAP). BCIS has been reported for many years and it is perhaps surprising that it took until 2009 for a full explanation and classification of BCIS to emerge. Olsen and colleagues looked back on over 1000 cemented hemi-arthroplasties, inserted after a proximal femoral fracture. The incidence of BCIS was over 20% and the incidence of a severe reaction resulting in cardiovascular collapse was 1.7%. It is worth comparing the data from Sweden with other studies from Northern Europe. The ASAP study observed the development of BCIS in a population of over 3500 cemented hemi-arthroplasties. BCIS was observed in 19% of cases with grade 2 or 3 occurring in 2.7% and 0.5%, respectively; the corresponding figures from this study are 5.1% and 1.7%. A study from Norway reported an incidence of intraoperative cardiovascular collapse or death (grade 3) of 0.5%, identical to the ASAP study. Although all these studies are observational and rely on single arterial pressure measurements and oxygen saturation data charted on anaesthesia records, the figures are comparative and do show that BCIS is a problem in those patients who have suffered a proximal femoral fracture. Perhaps this is not surprising as soon as bone cement was used for hip surgery, reports started to emerge of problems. The National Patient Safety Agency (NPSA) issued a rapid response report following a series of deaths in 2009. It is beyond the scope of this editorial to discuss the aetiology of BCIS, but the data from Olsen and colleagues have identified some of those who are most likely to be affected, which gives those treating these patients some guidance on what type of fixation should be used. There are four important factors to consider for BCIS, the patient, the surgeon, the anaesthetist, and the theatre team involved in the operation. The NPSA warning in 2009 highlighted that patients with poor cardiorespiratory reserve were at risk. The analysis from the paper by Olsen and colleagues has confirmed these findings. Independent predictors of severe BCIS were high ASA grade, the presence of pre-existing chronic obstructive pulmonary disease, and medication with diuretics or warfarin. The outcome for the patients who develop grade 2 and 3 BCIS was poor, and they accounted for 95% of those patients who died within 2 days of surgery in the present study. An analysis of mortality from the National Hip Fracture Database (NHFD) has revealed an increase in deaths from cemented compared with uncemented prostheses at 24 h, which does appear to tie in with the incidence of BCIS from ASAP and the observational studies that have emerged from Scandinavia. 4 Another question to ask is whether BCIS is a problem in elective hip arthroplasty surgery. A rate of intraoperative mortality for elective total hip arthroplasty of about 0.1% has been reported. 7 The number of patients having primary hip arthroplasties with an ASA score of III or IV was 15%, this has increased to 22% for NHS hospitals by 2012. The 90 day mortality from elective hip arthroplasty is 0.29% and has decreased steadily, despite the increasing age and complexity of patients. This lower incidence is due to the elective cases being younger and medically fitter with less cardiovascular disease in comparison with those patients with a hip fracture. The advantages of a cemented arthroplasty for hip fracture cases have been summarized in the NICE guidelines on this topic. The cemented arthroplasty, in comparison with the uncemented designs, lead to a hip that has less residual pain and better regain of mobility. – 11 The need for revision arthroplasty is also reduced for the cemented implants. 9 10 12 This increased re-operation rate is due to implant loosening causing pain and a larger risk of re-fracture around the implant. While the 1 day mortality is increased for the cemented prosthesis, mortality thereafter shows no difference and by 1 yr, there is even a trend to a lower mortality for those with the cemented prosthesis. Anaesthetists should increase their vigilance during a cemented procedure. There are a number of crucial factors that can make the likelihood of BCIS more common, apart from patient selection. Maintenance of arterial pressure during surgery and adequate circulating volume should be in place before cement insertion. In those patients who have cardiovascular compromise, the insertion of an arterial line will give immediate notice of alterations in arterial pressure. End-tidal carbon dioxide measurement may decrease and this is a useful monitor in those receiving general anaesthesia, which is about 50% in England, Wales, and Northern Ireland. For the surgeon, the femur needs to be carefully prepared and dried. A cement gun must be used and for the frailer patients, pressurization of the cement should be avoided. BJA Editorials

Standardising anaesthesia for hip fracture surgery

One of the more striking findings of the Anaesthesia Sprint Audit of Practice (ASAP) [2, 3] is the continuing wide national variation in anaesthesia practice for hip fracture, variation which remains similar in extent to that found throughout the modern era of hip fracture treatment [4–6]. Some variation in practice is inevitable, as a natural consequence of pathophysiological differences between patients. However, the frequency distribution of age and comorbidity is too homogenous nationally to account for the variation entirely: hip fracture patients are as ‘similar’ in Brighton as they are in Nottingham, Peterborough or elsewhere. Similarly, relatively few hip fracture patients are ‘complex’: only 2.9% are admitted with a Nottingham Hip Fracture Score of 8/10 or more (and 11.2% ≥ 7/10). Nonpatient ‘artificial’ factors, therefore, appear to account for the majority of the variation measured. Anaesthetists are undoubtedly providing what they believe to be the safest care, but organisational, educational and cultural factors are affecting the way in which anaesthesia care is delivered to hip fracture patients, and as a consequence, a spectrum of care occurs. Some hospitals and some practitioners are delivering high-quality anaesthesia care, achieving high rates of nerve block administration (92% in Ulster Hospital) and low rates of intra-operative hypotension (37% in South Tyneside District Hospital), for example [2]. Other hospitals and individual practitioners are delivering what would be considered unusual or poor care by any measure, particularly in relation to the quasi-legal professional standards described by the AAGBI management of proximal femoral fracture guidelines [7] – 3.5 ml 0.5% hyperbaric bupivacaine or more were administered intra-thecally to 47 patients during the three-month ASAP data collection period (and ≥ 3 ml to 925 patients), for example.

Clopidogrel has no effect on mortality from hip fracture

Over 76,000 patients in the UK sustain a proximal femoral fracture. Clopidogrel is currently the worlds second best selling drug. There has been much recent controversy surrounding the optimal time for surgical intervention in this medically challenging group of patients. This consecutive series of 1225 patients from our unit over six years included thirty patients concurrently taking clopidogrel whilst sustaining a hip fracture. Our study demonstrated no significant difference in ASA grade, intra-operative blood loss or subsequent transfusion, post-operative wound complication, or mortality to one year in those taking clopidogrel. The authors therefore advocate timely surgical intervention as rapidly as circumstances allow.

General versus regional anaesthesia for hip fractures. A pilot randomised controlled trial of 322 patients

Uncertainty remains regarding the optimum method of anaesthesia for hip fracture surgery. We randomised 322 patients with a hip fracture to receive either general anaesthesia or regional (spinal) anaesthesia. Surviving patients were followed up to 1 year from injury. There was no notable difference in the outcomes of hospital stay, need for blood transfusion or post-operative complications between groups. 30-day mortality was marginally reduced for spinal anaesthesia 7/164(4.3%) versus 5/158(3.2%) (p=0.57), whilst at 1 year it was less for general anaesthesia 20/163(12.1%) versus 32/158(20.2%) (p=0.05). Within the confines of the limited patient numbers studied we conclude that there are no marked differences in outcome between the two techniques.