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Welsh Anaesthetic Trainees Journal Club

Journal Club: 20th June 2018

Association of Frailty with Failure to Rescue After Low-Risk and High-Risk Inpatient Surgery.

JAMA Surg. doi:10.1001/jamasurg.2018.0214

Presented by: Dr Steve Young

Background

This is a retrospective data set study from American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP). It investigated the role of frailty in post operative outcomes

Design & Setting

It used the above data set from 2005-2012. It looked at patients in the data, assessed their frailty using the Risk Analysis Index and then compared their outcomes along with type of procedure (low risk or high risk)

Subjects

  • In patients undergoing general, vascular, cardiac, thoracic and orthopaedic operations 2005-2012 at 600 hospitals in the United States.
  • Final analysed data set just under 1 million patients.

Intervention

This was an observational study

Outcomes   

Complication rates after inpatient surgery

Results

Increasing frailty increases your rate of complications

Conclusions

Preoperative patient frailty is an important risk factor for post operative complications

Strengths

  • Very large comprehensive data set.
  • Statistically significant outcomes
  • Clinically significant outcomes
  • Relevant to our practice

Weaknesses

  • Retrospective observational study
  • No intervention
  • The outcome is pretty obvious

Implications

Although probably a useful study to confirm obviousness, I’m not sure how much this adds to my practice

Potential for impact

As above, I am not sure this adds much but it does confirm what we thought.

Journal Club: 6th June 2018

Restrictive versus Liberal Fluid Therapy for Major Abdominal Surgery (RELIEF)

 New England Journal of Medicine. DOI: 10.1056/NEJMoa1801601.

 Presented by: Dr Helen Ivatt Clinical Fellow Anaesthetics

 Background

Traditional intravenous fluid regimes have been shown to deliver up to 7 litres fluid on the day of surgery resulting in significant tissue oedema and weight gain.  In 2003 Brandstrup et al demonstrated a halving of the complication rate with a near zero fluid balance compared with a judicious fluid regime1. Several other small studies demonstrated a similar effect 2-4.  Fluid restriction in major abdominal surgery is supported by recent consensus statements, and the enhanced recovery after surgery (ERAS) pathway which is widely adopted as a standard of care during major abdominal surgery also takes this approach5.  However, the evidence is not comprehensive or conclusive therefore the RELIEF trial was designed to compare outcomes using a restrictive v’s liberal fluid regime in high risk patients undergoing major abdominal surgery.

 Design & Setting

RELIEF is a large, multicentre, randomised, international, single blind, pragmatic trial, with patients randomly assigned to either restrictive or liberal fluid groups, stratified by site and by planned high dependency unit (HDU) or intensive care unit (ICU) admission.

The study ran from May 2013 – Sept 2016 in 47 centres across seven countries and included 3000 participants.

 Subjects

Inclusion criteria

Adults undergoing elective major abdominal surgery that included a skin incision with an expected duration of at least 2 hours and an expected hospital stay of at least 3 days who were at increased risk of complications defined by at least one of the following:

  • ≥70 years
  • Coronary artery disease
  • Heart failure
  • Diabetes (On oral hypoglycaemics +/- Insulin)
  • Preoperative serum creatinine >200μmol/L
  • BMI >35kg/m2
  • Preoperative serum albumin <30g/l
  • Anaerobic threshold <12ml/kg/min

Or two or more of the following:

  • ASA 3 or 4
  • Chronic respiratory disease
  • BMI 35kg/m2
  • Anaerobic threshold 12 – 14 mL/kg/min
  • Aortic or peripheral vascular disease
  • Preoperative Hb <100g/L
  • Preoperative serum creatinine 150-199 μmol/L

Exclusion criteria

  • Time-critical surgery
  • ASA 5
  • Chronic renal failure requiring dialysis
  • Pulmonary or cardiac surgery
  • Liver resection
  • Minor or intermediate surgery (e.g. lap cholecystectomy, TURP, inguinal hernia repair.)

Randomisation

Patients were randomly assigned in a 1:1 ratio using a web based service.  Permuted blocks stratified by both site and planned post op area of care (ICU, HDU or Ward) were used to ensure that prognostic factors and patient characteristics were balanced between groups.

Power calculation

Sample size calculation was based on the groups own data and other published studies.  A type I error of 0.05 was set along with an expected disability free survival at 1yr of 65% and a hazard ratio of >1.25.  This estimated that 1300 patients would be required in each group to provide 90% power thus a target recruitment of 2800 patients was set to make up for losses.

As the event rate was significantly less than expected (14.6% rather than an expected 35%) the sample size was increased to 3000 to provide 80% power.

Intervention

Participants were assigned to either Liberal or Restrictive fluid groups:

Liberal fluid group

  • 10ml/kg bolus of crystalloid at the start of surgery.
  • 8ml/kg/hr crystalloid until the end of surgery (reduced if clinically indicated after 4hrs)
  • Bolus colloid/blood was used intraoperatively to replace blood loss (mL for mL)
  • Maintenance 1.5ml/kg/hr for at least 24 hrs (reduced or increased according to hypovolaemia, fluid overload etc).
  • Treat hypotension with a fluid bolus in the first instance

Weight >100kg both bolus and maintenance limited to that for a 100kg patient.

Restrictive (‘zero balance’) intravenous fluid group

  • ≤5 mL/kg bolus of crystalloid at the beginning of surgery
  • 5 mL/kg/hr was to be administered until the end of surgery
  • Bolus colloid/blood was used intraoperatively to replace blood loss (mL for mL)
  • Maintenance 0.8mL/kg/hr until cessation of fluid within 24 hours (Reduced or increased according to hypovolaemia, fluid overload etc)
  • Treat hypotension with vasoconstrictor in the first instance.

Outcomes

Primary endpoint

Disability free survival at 1yr after surgery (Measured by the WHODAS score).

Secondary endpoints

  • All-cause mortality at 90 days, and survival up to 12 months after surgery.
  • Composite and individual incidence of sepsis, surgical site infection, anastomotic leak and pneumonia.
  • AKI
  • Pulmonary oedema
  • Duration of mechanical ventilation
  • Day 3 CRP
  • Lactate within 24hrs of surgery
  • Blood transfusion following surgery
  • Unplanned admission to HDU/ICU within 30 days of surgery.
  • Total HDU/ICU stay.
  • Total hospital stay up to day 30.
  • Quality of recovery on days 1, 3 and 30.

 Results

2983 out of 3000 met criteria for a modified intention to treat population (patients had to be both randomised and undergo induction of GA). There were no significant baseline differences and the loss to follow up was small at 3.3% (82 patients).

In the first 24 hrs there was a significant difference in median fluid infusion (3.7L v’s 6.1L P<0.001).

There was no significant difference between groups for the primary endpoint of disability free survival. Subgroup analysis also failed to find a difference.

Acute kidney injury occurred in 124 (8.6%) patients in the restrictive group and 72 (5%) patients in the liberal group (p<0.001).

The need for renal replacement therapy and the incidence of surgical site infection was significantly greater in the restricted group but significance was lost after adjustment for multiple comparisons.

No significant difference was found with any of the other secondary outcomes.

 Conclusions

The authors conclude that in patients at increased risk for complications while undergoing major abdominal surgery, a restrictive fluid regimen was not associated with a higher rate of disability-free survival than a liberal fluid regimen 1 year after surgery. However, the restrictive regimen was associated with a higher rate of acute kidney injury.

 Strengths

  • Large multicentre, multinational randomised design.
  • Modified intention to treat approach.
  • Primary outcome of disability free survival may be seen as more meaningful endpoint than the traditional outcomes of morbidity and mortality.
  • Correction for multiple testing carried out.

 Weaknesses

  • Clinicians could not be blinded to volume administration, which could have lead to bias in outcome recording however research staff responsible for the primary outcome were blinded to allocated treatment.
  • The surgeries performed were heterogenous which risks a cancelling out of effect, and a lack of generalizability.
  • Fluid administered after the first 24hrs was not recorded.
  • The event rate was lower than previously documented in the literature meaning that the study was less well powered than previously thought and increases the chance of a type II error.
  • The ERAS protocol was not adhered to in a large number of patients though this was not significantly different between groups

 Implications

The findings of this fairly robust study do not support the previously accepted notion that fluid restriction is better that judicious IV infusion.  There are a number of reasons why this may be the case; previous papers have reported greater infusion volumes on the day of surgery (up to 7L intraoperatively), and much greater weight gains than demonstrated in the current paper (4-6kg cf 0.3-1.6kg).  Some of the reason for this weight gain will be fluid volume related but it may also be related to the fact that surgical techniques are minimally invasive and so reduces the metabolic stress that leads to fluid retention.

Therefore we could conclude that with modern surgical techniques and fluid regimes, modest fluid administration that exceeds a zero balance is no longer associated with harm to the patient and may reduce the incidence of AKI. The paper should, however, not be used to support excessive IV administration.

Potential for impact

This is a well designed large multicentre study which is the first of it’s kind.  It is applicable to our high risk patients and though it has limitations it rejects the current trend for fluid restriction and advocates a more modest approach to fluid administration in the 24hrs post surgery.

 References

  1. Brandstrup B, Tønnesen H,Beier-Holgersen R, et al. Effects of intravenous fluid restriction on postoperative complications: comparison of two perioperative fluid regimens: a randomized assessor-blinded multicenter trial. Ann Surg 2003;238:641-648.
  2. de Aguilar-Nascimento JE, Diniz BN, do Carmo AV, Silveira EA, Silva RM. Clinical benefits after the implementation of a protocol of restricted perioperative intravenous crystalloid fluids in major abdominal operations. World J Surg 2009;33:925-930.
  3. Lobo DN, Bostock KA, Neal KR, Perkins AC, Rowlands BJ, Allison SP. Effect of salt and water balance on recovery of gastrointestinal function after elective colonic resection: a randomised controlled trial. Lancet 2002;359:1812-1818.
  4. McArdle GT, McAuley DF, McKinley A, Blair P, Hoper M, Harkin DW. Preliminary results of a prospective randomized trial of restrictive versus standard fluid regime in elective open abdominal aortic aneurysm repair. Ann Surg 2009;250:28-34.
  5. Gustafsson UO, Scott MJ, Schwenk W, et al. Guidelines for perioperative care in elective colonic surgery: Enhanced Recovery After Surgery (ERAS) Society recommendations. Clin Nutr 2012;31:783-800.

Journal Club: 30th May 2018

Abnormal routine pre-operative test results and their impact on anaesthetic management: An observational study.

Indian Journal of Anaesthetics 2018;62:23-8. DOI: 10.4103/ija.IJA_223_17

Presented by: Dr Benjamin O’Donovan, ST4 Anaesthetics

Background

In spite of guidelines from the ASA and NICE, and a lack of evidence for ‘routine’ pre-operative investigations they are still frequently carried out. These investigations may identify previously unknown abnormalities resulting in changes to pre-operative management. This study aimed to assess the prevalence of abnormal test results and their impact on the peri-operative management of patients undergoing elective surgery.

Design & Setting

An observational prospective study, in a tertiary care teaching hospital.

Subjects

414 consecutive patients aged 12 years or older, male or female, attending preassessment clinic for non-cardiac surgery were used.

Exclusions

  • Pregnant patients
  • Bedridden or immobile patients (unable to assess body weight)
  • Patients under the age of 12 years old

Intervention

Data collected:

  • Demographics
  • ASA grade
  • Grade of surgery (NICE classification)
  • All investigations and results prior to being declared fit for surgery were noted including:
    • Haemoglobin less than 10g/dL
    • Platelets less than 100
    • Elevated blood sugar
    • Abnormal TFTs
  • Newly diagnosed comorbidities from investigations were noted.

NB: New diagnoses of hypertension were not counted

Outcomes

  • An abnormal result was said to be ‘impactful’ if it resulting in referral, delay, further investigations, retesting or changes in anaesthetic management plan.
  • This was said to be a significant impact if the resulting change was in the perioperative anaesthetic management.
  • An abnormal but potentially expected result leading to a change in management was not counted.

Results

  • 345 (11.6%) of results were abnormal
    • 56 abnormalities had an impact
    • 20 had a significant impact.

NNI for significant impact was 21 and detecting new abnormality was 28. Average

Conclusions

  • Over half of patients in the study have abnormal test results
  • 8% of tests have an impact on patients
  • 67% of tests have significant impact.

Strengths

  • National Journal
  • Prospective study
  • Appropriate study power calculation
  • Largely reasonable exclusion criteria
  • Positive subject to investigate in terms of rationalising healthcare expenditure.

Weaknesses

  • Observational study
  • Single centre
  • Unclear if protocol for requesting pre-operative investigations
  • 12 seems an odd age for cut off of lower limit
  • Not affecting peri-operative management doesn’t necessarily mean no significant patient impact.

Implications

We over investigate our patients by the parameters of impact/significant impact set out in this study.

Potential for impact

Given that this study indicates that patients are over investigated at pre-operative assessment there would be the potential for significant cost-saving by reducing the number of investigations requested.

 

 

Journal Club: 23rd May 2018

Perioperative aspirin therapy in non-cardiac surgery: A systematic review and meta-analysis of randomized controlled trials

International Journal of Cardiology 2018;258:59–67 

doi: 10.1016/j.ijcard.2017.12.088 0167-5273

 Presented by: Dr L Jones

Background

  • Cardiovascular and bleeding events are amongst the leading complications during surgery
  • Aspirin is the cornerstone of secondary prevention of cardiovascular disease
  • As an irreversible cyclooxygenase-I inhibitor, aspirin poses a bleeding risk
  • For non-cardiac surgery aspirin’s benefits and bleeding risks remain unclear

Design & Setting

  • A systematic review and meta-analysis of randomised controlled trials
  • Aspirin v no aspirin in non-cardiac surgery
  • All cause mortality, cardiovascular mortality, arterial ischaemic events, venous thromboembolic events and bleeding events separately evaluated

Subjects

  • 7 relevant prospective randomised controlled trials
  • 28302 patients
  • Intermediate risk cardiovascular-risk surgery

Intervention

  • Different for every trial but a variation on aspirin at various doses v no aspirin

 Outcomes

  • All cause mortality (All trials)
  • Cardiovascular mortality (All trials)
  • Perioperative MI (All trials)
  • Major Bleeding (All trials)
  • Cerebrovascular events (6 trials)
  • Peripheral arterial events (3 trials)
  • Venous thromboembolic events (4 trials)

 Results

  • All-cause mortality (3.7% vs. 3.8%; odds ratio (OR) 0.97, CI 0.86–1.10) and cardiovascular mortality (2.0% vs. 2.1%, OR 0.92; CI 0.78–1.09) were not different in aspirin vs. no aspirin groups.
  • Arterial ischemic events showed no differences, including myocardial infarction (2.5% (aspirin) vs. 2.5% (no aspirin)), cerebrovascular events (0.6% (aspirin) vs. 0.6% (no aspirin)) and peripheral arterial events (0.2% (aspirin) vs. 0.3% (no aspirin)).
  • Aspirin significantly reduced the risk for venous thromboembolic events (VTE; 1.5% (aspirin) vs. 2.0% (no aspirin); OR 0.74, CI 0.59–0.94, p = 0.02).
  • Perioperative major bleeding was significantly more frequent in aspirin groups (4.4% vs. 3.7%; OR 1.18, CI 1.05 to 1.33, p = 0.007).

 Conclusions

  • Aspirin showed no difference in terms of mortality v no aspirin for intermediate risk non cardiac surgery
  • Aspirin significantly reduced the risk for VTE but also had a significantly higher major bleeding risk

 Strengths

  • Meta-analysis of RCTs
  • High sample size
  • Easy to measure primary outcomes

 Weaknesses

  • Not all trials included secondary outcome measures eg. VTE risk
  • Variance in doses of aspirin per study
  • Some studies (PEP, POISE-II and STRATEGEM) used other anticoagulants as well as aspirin

 Implications

  • Aspirin showed no mortality benefit therefore the initiation/ continuation of aspirin in the perioperative period for intermediate risk surgery is not recommended.
  • Aspirin showed a 25% risk reduction in VTE for orthopaedic surgery and therefore should be considered as prophylaxis alongside other anticoagulants

 Potential for impact

  • Conclusive evidence for stopping aspirin in the preoperative period for intermediate risk surgery. This helps in decision making in the pre assessment clinic.
  • Consideration for adding aspirin to VTE prophylaxis protocols

Journal Club: 16th May 2018

Incidence and risk factors of anaesthetic-related perioperative cardiac arrest. European Journal of Anaesthesiology 2017;34:1–7 doi:10.1097/EJA.0000000000000685

 Presented by: Dr R Dean-Paccagnella

Background

  • Many studies have analysed perioperative mortality in speciality sub-groups, but few have looked at unselected patient populations. Many studies have excluded patients undergoing cardiac surgery.
  • Previous papers have studied perioperative mortality but have not independently reviewed the incidence and risk factors of cardiac arrest.
  • This study aims to measure the incidence of perioperative cardiac arrest in an unselected anaesthetic population and retrospectively identify significant risk factors.

Design & Setting

  • Retrospective cohort study of non-ITU patients undergoing anaesthesia between January 2007 and December 2012 at a single tertiary hospital in Cologne, Germany.

Subjects

  • 169,000 adult and paediatric patients underwent anaesthetic procedures within the time period.
  • Study population (n 318) was identified by the screening of critical incident report forms, performed by the authors.
  • Cases were categorised into 1. “anaesthesia related” (directly caused by an anaesthetic procedure), 2. “anaesthesia contributory” (caused by both surgical and anaesthetic events) or 3. “anaesthesia contributory” (possibly caused by factors under the control of the anaesthetist).

Intervention

  • Undifferentiated anaesthetic procedures were analysed retrospectively.

Outcomes

  • Incidence of pulselessness requiring chest compressions within 24hours after anaesthetic procedure.

Results

  • Incidence of perioperative cardiac arrest was 5.8/10,000 anaesthetic cases (95% CI 4.7-7.0).
  • Significantly increased risk of perioperative cardiac arrest was associated with ASA grade or 3 or more, revised cardiac risk index of 3 or more, NYHA or 3 or more, out of hours procedures, emergency surgery and pre-existing cardiomyopathy.
  • Multi-variate logistic regression identified 3 predictors of perioperative cardiac arrest. ASA grade of ≥3 (OR 2.59, p=0.007, 95% CI 1.29 to 5.19), emergency surgery (OR 4.00, p=0.001, 95% CI 2.15 to 7.54) and pre-existing cardiomyopathy (OR 17.48, p= <0.001, 95% CI 6.18 to 51.51).
  • Age over 75 years or less than 3 years, Gender, BMI ≥30 kg m3 , and patients with known difficult airways were not identified to be at significantly altered risk of perioperative cardiac arrest.

Conclusions

  • Patients with an ASA physical status grade of ≥3, undergoing emergency surgery or with pre-existing cardiomyopathy appear to be at an increased risk of perioperative cardiac arrest in this single centre European university hospital population.
  • Incidence of paediatric cardiac arrest directly caused by anaesthesia was high (5 of 12 cardiac arrests directly related to anaesthetic procedure).

Strengths

  • Clinically relevant question addressing entire anaesthetic population.
  • Findings are in-line with previous papers addressing ASA grade and risk of anaesthesia related cardiac arrest.

Weaknesses

  • Risk factors were identified retrospectively by reviewers. NYHA classification appears to have been categorised retrospectively by investigators.
  • Strength of relationship between anaesthetic procedure and cardiac arrest categorised by authors (although independently).
  • Single centre European study which may not provide generalisable results.
  • Main outcome measure is an infrequent event, and as such small variation in number of events will greatly influence the frequency reported.

Implications

  • ASA grading, urgency of surgery and pre-operative identification of cardiomyopathy may help identify high risk cases.
  • Further studies of peri-operative cardiac arrest would be improved by establishing a consensus for the definition of anaesthesia-related and anaesthesia-contributory cardiac arrests.
  • Incidence of anaesthesia-related cardiac arrest appears to remain relatively high in the paediatric population.

Potential for impact

  • If felt to be generalisable, ASA grade ≥3, emergency surgery and cardiomyopathy may indicate patients at significantly increased risk of perioperative cardiac arrest, although this remains an infrequent event.

 

 

Journal Club: 9th May 2018

The Clinical Impact of Cardiology Consultation Prior to Major Vascular Surgery

Annals of Surgery 2018, 267 (1): 189-195. doi: 10.1097/SLA.0000000000002014.

 Presented by: Dr S O’Beirn

Background

  • Cardiovascular complications are the leading cause of morbidity and mortality in adult patients undergoing major vascular surgery.
  • Despite the perceived benefit of preoperative Cardiology consultation in high risk patients the evidence for this and the guidance for which patients it would be of greatest benefit remain unclear.
  • This study aims to analyse the impact of pre-operative Cardiology consultation rates on the incidence of post-operative Myocardial Infarction (MI) at the individual and Hospital level.

 Design & Setting

  • Retrospective analysis of a large prospective multicentre observational registry based in 29 hospitals across the state of Michigan from Jan ’12 to Dec ’14.

Subjects

  • 5191 cases undergoing Open Peripheral Arterial Bypass (n=3037), Open Abdominal Aortic Aneurysm Repair (n=332) or Endovascular Aneurysm Repair (n=1822).
  • Cases excluded Emergency surgery, Carotid Endarterectomy or Stenting, Age <18 or BMI <10 or >80.

Intervention

  • Preoperative Cardiology consult defined as a documented Cardiology clinic or In hospital consultation within 6 months prior to the procedure.

Outcomes

  • Primary Outcome of Perioperative Myocardial Infarction (PoMI) defined as a rise in cardiac biomarkers combined with either Ischaemic symptoms, new Ischaemic ECG changes, pathological Q waves or Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality.
  • Secondary Outcomes included the development of a dysrhythmia, congestive heart failure or cardiac arrest within the initial hospitalisation following the operation.

Results

  • Patients undergoing pre-operative Cardiology consultations had significantly higher rates of Perioperative MI (2.7% vs 1.47%, p=0.002).
  • No significant variation in mortality (1.57% vs 1.10%, p=0.147).
  • Huge variation in rates of Cardiology consultation across centres (6.9%-87.5%, median 53.3%).
  • Lower rate of Perioperative MI at the quartile of centres with the highest rate of consultations OR 0.52 (0.27-0.98, 95% CI, p=0.045).

Conclusions

  • Higher rate of PoMI amongst patients undergoing pre-operative Cardiology consultation, though this can likely be explained by these patients being at higher risk due to operative and patient factors.
  • No significant variation in rates of PoMI within quartiles when cases grouped according to Revised Cardiac Risk Index.
  • Reduction of PoMI seen in hospitals with higher rates of preoperative Cardiology consultation. The specific mechanism of this is unclear. Suggestion of “Hospital culture” as a factor.

Strengths

  • Large sample size at the patient level.
  • Reporting of negative results.
  • Clinically relevant question.

Weaknesses

  • Retrospective analysis of previously published data.
  • Acknowledged limited data on the outcome of preoperative consultations.
  • Significant cofounders unaccounted for (Intraoperative anaesthetic and fluid management, technical skill of the surgeon, critical care management).
  • Lack of cost analysis.
  • Potential for lack of generalisability given all centres within 1 state.
  • Significant inter-quartile variability within rates of PoMI among centres with low rates of preoperative consultation.
  • Multiple implications drawn from lower rates of PoMI amongst high preoperative consultation centres despite only just attaining significance at a 95% CI (p=0.045).

Implications

  • Based on this study, centres with higher rates of preoperative medical consultation have lower rates of perioperative complications, specifically perioperative MI amongst patients undergoing elective major Vascular surgery.
  • However, this is not demonstrated by this data on a patient level and the implication is that variation in hospital culture is a key confounder.

Potential for impact

  • Limited potential for impact as failure to demonstrate improvements in perioperative outcomes on the patient level and lack of suggestion as to which patient groups may benefit from undergoing preoperative consultation.

 

Journal Club: 25th April 2018

Effectiveness of an internet-based perioperative care programme to enhance postoperative recovery in gynaecological patients: cluster controlled trial with randomised stepped-wedge implementation

BMJ Open 2018;8:e017781. doi:10.1136/ bmjopen-2017-017781

Presented by: Dr G Roberts

Background

Perioperative care is often a fragmented process between disciplines, patients, clinicians and hospitals.  A proof of concept trial had previously demonstrated in gynaecological care that an internet-based peri-operative care platform could potentially empower patients during this period; the aim to enhance post-operative recovery through appropriate self-management strategies, reduce inappropriate recovery behaviour and ultimately enable a quicker return to work.

Design & Setting

  • Three year (2011 to 2014) study sequentially across nine hospitals using a stepped-wedge cluster randomised trial (https://www.bmj.com/content/350/bmj.h391)
  • Eligible hospitals had to perform at least 100 hysterectomies or laparoscopic adnexal surgery. Hospitals served as the control group until the care programme was sequentially implemented.
  • Study design did not allow for blinding, but group allocation was concealed from patient until consent obtained. Data analysts blinded.

Subjects

Over 400 employed women aged between 18 – 65 scheduled for surgery of benign gynaecological disease.

Inclusion

  • Scheduled for hysterectomy (vaginal, laparoscopic or abdominal) and/or laparoscopic adnexal surgery.
  • Aged between 18 – 65.
  • Employed for at least eight hours a week.

Exclusion

  • Severe benign comorbidity or malignancy.
  • Pregnancy
  • Computer or internet illiterate.
  • Insufficient command of Dutch language.

Intervention

Internet-based care programme sequentially rolled out using a multifaceted implementation strategy. Patients were allocated to either the care programme (intervention) or usual care (control).  The care programme included an e-health intervention equipping patients with tailored personalised convalescence advice that had been designed by patients, gynaecologists, GPs and occupational physicians. Post-operatively, the web portal contained an interactive self-assessment tool to monitor recovery.

Outcomes

Primary

  • Sick leave duration until full sustainable return to work (defined as the resumption of own work or other work with equal earnings, for at least four weeks without recurrence of sick leave).

Secondary

  • Functional health status
  • Recovery
  • Self-efficacy
  • Coping
  • Pain

 Results

  • 433 participants recruited from potentially 1591.
  • Data for primary outcome obtained from 401 participants while data for secondary outcomes obtained from 334 participants.
  • 8% of participants in intervention group used the website programme as intended.
  • Median duration until full sustainable return to work was 49 days in intervention group and 62 days in control group.
  • No demonstrable difference in functional health status, self-efficacy and coping.

 Conclusions

The use of internet-based information technology to facilitate a gynaecology patient’s perioperative journey may result in a reduction in post-operative sick days.  It would be worth other surgical specialties adopting and evaluating this method, while identifying those patients who might benefit most from this approach.

Strengths

  • Assessment of both patient and organisation.
  • Intention-to-treat.
  • Sub-group analysis.

Weaknesses

  • Cluster design may have led to recruitment bias.
  • The online platform had a proof of concept but not necessarily validated.
  • Just under a third of eligible patients were recruited, the majority of whom either declined to participate or were not eligible.
  • Due to the eligibility criteria requiring employed women who were computer literate, a high proportion of participants were deemed highly educated – How can conclusions apply across the general population?
  • There was significantly more loss-to-follow up in the intervention group.

Implications

  • There is a potentially large positive bio-psycho-social impact if these results are proved to be reproducible.
  • Reduction in sick days would have a positive socio-economic effect.

 Potential for impact

With more focus and energy being applied to the process of perioperative care by many stakeholders and the increasing use of information technology, this approach may prove to empower patients during their perioperative journey and lead to better recovery profiles.  Care is needed however to ensure that there is more to recovery than simply ‘return to work’.

Journal Club: 18th April 2018

Normal saline versus a balanced crystalloid for goal-directed perioperative fluid therapy in major abdominal surgery: a double-blind randomised controlled study

British Journal of Anaesthesia 2018;120(2):274-283

Presented by: Dr I Rees

Background

  • Normal saline 0.9% amongst most commonly used crystalloid for fluid therapy
  • However normal saline not ‘normal’
    • Sodium and chloride concentrations 154mmol/l
    • Risk of hyperchloraemic metabolic acidosis and reduced anion gap
    • Linked to increased risk of renal dysfunction, transfusion and mortality in patients undergoing abdominal surgery
  • Balanced crystalloids contain metabolisable anions (lactate or acetate)
    • Maintain electrolyte stability
    • Less associated with metabolic acidosis
    • Metabolised to bicarbonate
  • Recent study in same centre demonstrated patients undergoing cadaveric renal transplantation required significantly less catecholamine support if receiving balanced crystalloid, compared to the group receiving normal saline
  • Authors hypothesised that patients undergoing major surgery might require less vasopressor support if they received a balanced crystalloid, as opposed to normal saline perioperatively

Design & Setting

  • Single-centre (Department of Anaesthesiology of the Medical University of Vienna, Austria)
  • Prospective double-blinded randomised controlled study of patients undergoing elective major abdominal surgery
  • Patients and anaesthetists blinded
  • Ethics approved
  • Sample size calculated (based on previous transplantation study) – 120 patients per group (240 total) to give α 5% and 80% power

Subjects

Inclusion criteria:

  1. Adult, non-pregnant patients
  2. Undergoing elective major abdominal surgery (any general, gynaecological or urological procedure requiring laparotomy)

Exclusion criteria:

  1. LV ejection fraction <30%
  2. Renal dysfunction (GFR <30ml/min) and severe liver disease
  3. Chronic inflammatory diseases requiring long-term steroids
  4. Pre-operative sepsis or critical care patients
  5. Contraindications to oesophageal doppler
  6. Intraoperative epidural analgesia

Intervention

  • Patients randomised on day of surgery to receive either normal saline or a chloride-reduced acetate-buffered balanced crystalloid (Elomel Isoton)
  • No pre-operative fluid infusion
  • Blinded fluids given to anaesthetist before induction of anaesthesia
  • Standardised anaesthetic:
    • Standardised induction (propofol 2-3mg/kg, rocuronium 0.6mg/kg and fentanyl 2-3mcg/kg)
    • Standard monitoring including arterial line and CVP + depth of anaesthesia monitoring (Narcotrend), train-of-four ulnar montoring and oesophageal doppler (CardioQ)
    • Sevoflurane administration according to Narcotrend; FiO2and fentanyl boluses according to clinical requirement; Rocuronium to maintain one or two twitches on TOF
    • Ventilation to maintain end-tidal CO2 near 35mmHg (~4.6kPa) – tidal volume 8-10ml/kg (LBW), peak pressure <30mmHg (~40cmH2O) and PEEP of 5mmHg (~7cmH2O) or higher according to patient need.
    • Temperature >36oC using forced air warmer and hourly arterial blood gases
    • Fluid maintenance 2ml/kg/hr (IBW as per Robinson’s formula) increased to 5ml/kg/hr on exposure of viscera
  • Target MAP according to pre-operative blood pressure the day before surgery:
Pre-operative Blood Pressure (mmHg) Intraoperative Target MAP (mmHg)
Hypotensive SBP <120 60
Normotensive SBP 120-139 / DBP 80-89 70
Hypertensive SBP >140 / DBP >90 80
  • If MAP fell, standardised protocol followed:
    • SV responsiveness assessed using 250ml fluid challenge
    • If >10% increase in SV but MAP still below desired value, further 250ml boluses until SV increase <10% or target MAP achieved
    • If target MAP still not achieved and SV ‘unresponsive’, phenylephrine 0.1-0.2mcg bolus given (maximum 0.8mcg/hr)
    • If still insufficient, noradrenaline infusion started at 0.01-0.02 mcg/kg/min and titrated to desired MAP by increments of 0.05-0.1mcg/kg
    • If SV fell by >10% of the value following the last fluid challenge, a further 250ml was given
    • Noradrenaline titrated down or stopped if fluid challenges sufficient in maintaining MAP
  • Exit criteria: pH below 7.2, bicarbonate below 14mmol/l, base excess below -10mmol/l or response to catecholamines insufficient – fluid changed to balanced crystalloid and study was terminated.

Outcomes

Primary:

  1. Need for vasopressors

Secondary:

  1. Total dose of catecholamines
  2. Total perioperative fluid
  3. Unplanned intensive care admissions

Results

  • Terminated early for safety reasons (hyperchloraemic metabolic acidosis) after discussion with study safety board and local authority
  • Only 60 of the total planned 240 were studied (30 in each group)
  • More patients required vasopressors in the normal saline group than the balanced crystalloid (97% vs67% respectively,p=0.033)
  • Median weight and duration-adjusted dose of norepinephrine were 0.11(0.00-0.45)mcg/kg/min in the normal saline group compared with 0.00mcg/kg/min in the balanced crystalloid group (p=0.003)
  • No difference between groups in total perioperative fluid and unplanned intensive care admissions
  • Cox regression showed need for vasopressors related to high volume of administered fluid, normal saline resuscitation and lower MAP

Conclusions

  • Study suggests that patients undergoing major abdominal surgery with normal saline fluid therapy have a significantly larger vasopressor requirement than those receiving a more physiological crystalloid.
  • Hyperchloraemia with or without acidosis may be a direct trigger for unfavourable cardiovascular effects – leads to increased nitric oxide, as seen in rats

Strengths

  • Focused question asked
  • Hypothesis based on previous study
  • Prospective double-blinded RCT
  • Patient groups comparable
  • Appropriate inclusion and exclusion criteria
  • Extremely standardised protocol
  • Appropriate statistical analysis i.e. Mann-Whitney U Test for quantitative, non-parametric analysis of 2 unpaired groups

Weaknesses

  • Terminated due to patient safety
  • Underpowered (67%) for primary outcome due to low numbers – power 90% for secondary outcomes
  • Single-centre
  • Protocol resulted in large amounts of intraoperative fluid infusion (median 3427ml of normal saline and 3144 of the balanced crystalloid)
  • No mention of blood products
  • No epidural or intrathecal block
  • Is it an important clinical question?

Implications/Potential for impact

  • Is our practice likely to change following this study?
  • Inference that normal saline may cause detrimental cardiovascular effects due to hyperchloraemic acidosis (leading to increased nitric oxide, as seen in rats) is interesting
  • Vast majority of anaesthetists likely to use a balanced crystalloid e.g Hartmann’s solution, rather than normal saline for elective adult surgery (save for a few circumstances e.g. liver failure etc) as it is more ‘physiological’ – why cause further stress during the stress response?

Following this underpowered study that put patients in harm’s way, I will do as the authors suggest i.e. exactly what I’ve been doing this entire time.

Journal Club: 11th April 2018

Personalised Prehabilitation in High-risk Patients Undergoing Elective Major Abdominal Surgery. A Randomised Blinded Controlled Trial.

 Annals of Surgery 2018;267(1):50-56 doi:10.1097/SLA.0000000000002293

Presented by: Rebeca Harris ST4

Background

  • Major abdominal surgery is associated with a high rate of postoperative complications, particularly in elderly patients with multiple comorbidities.
  • Aerobic capacity determines postoperative functional reserve, which is negatively associated with postoperative morbidity and mortality.
  • Prehabilitation exercise programmes are postulated to improve aerobic capacity, and thereby reduce postoperative complications.
  • Previous studies have shown a bias towards low-risk patients, and lack of evidence on postoperative clinical outcomes.
  • Prehabilitation is defined as a preparatory intervention aiming to increase aerobic capacity. Methods include supervised endurance exercise training and the promotion of physical activity.

Design & Setting

  • Single centre: Hospital Clinic de Barcelona
  • Patients were blindly randomized
  • Collaborating anaesthetists and surgeons were blinded to patient’s allocation
  • Ethics approved
  • Sample size prospectively powered (as standard, accepting risks of: α 0.05 and β 0.2), based on:
    • the reduction rate of patients with postoperative complications as the main outcome
    • considering the local colorectal complication rate (30%), and
    • anticipating up to 20% drop out
    • Intention-to-treat analysis

Subjects

High risk patients for elective major abdominal surgery

Inclusion criteria:

  • Elective major abdominal surgery
  • High risk defined by all of the following:
    • Age > 70 and/or ASA III/IV
    • Duke Activity Status Index Score < 46
    • Preop schedule allowed at least 4 weeks for the prehabilitation intervention

Exclusion criteria:

  • Non-elective surgery
  • Unstable cardiorespiratory disease
  • Locomotor limitations precluding exercise training
  • Cognitive deterioration impeding adherence to the programme

Intervention

  • Baseline assessment within 1 week of preoperative assessment
  • Reassessment 1 week before surgery

Standard care:

  • Physical activity, nutritional and smoking cessation advice
  • IV iron if indicated for anaemia
  • Nutritional intervention if high-risk for malnutrition

Intervention:

  • Personalised prehabilitation programme based on health and social circumstances
  • Mostly community based
  • 3 major aspects
    • Motivational interview to assess adherence profile. Tailored physical activity programme then co-designed with the patient
    • Personalised daily physical activity programme
      • Pedometer to measure steps, then feedback and optimization
    • Supervised high intensity endurance exercise programme
      • 1-3 per week
      • Exercise bike interval training, tailored to increase intensity over time, based on work rate
      • Pulse oximetry and self-perceived exertion measured

Outcomes

Primary

  • Number of patients with a complication

Secondary

  • Number and severity of postoperative complications
  • Hospital and ICU length of stay

Other

  • Endurance time
  • Distance covered in 6 minute walking test
  • Physical activity (by validated patient survey)
  • Self perceived health status (by validated patient survey)
  • Psychological status (by HADS patient survey)
  • Pulmonary function tests
  • Cardiorespiratory exercise tests

 Results

Baseline characteristics

  • 209 assessed over 3 years – 144 eligible and randomised (> 70 per group, as per power analysis minimum)
  • Comparable patient characteristics between groups
  • 19 did not receive operation, so excluded mid-trial
  • Control: 1 unable to perform exercise testing, 6 abandoned
  • Intervention: 4 unable to perform exercise testing, 4 abandoned
  • 56 (Control) and 54 (Intervention) completed trial (< 70 per group, and > 20% dropout rate, thus underpowered)

 Control

  • No change in baseline characteristics at start vs 1 week pre-surgery

 Prehabilitation intervention

  • Mean duration 6 weeks + 12 supervised exercise session
  • PRMIARY OUTCOME
    • 50% reduction in number of patients with complications: 31% vs 62%, RR 0.5 (95% CI 0.3-0.8), p = 0.001
  • SECONDARY OUTCOMES:
    • Increasein Endurance Time (135%, p < 0.001)
    • Increasein Physical Activity Index (37 points, p< 0.001)
    • No significant difference in intraoperative parameters, but trend towards lower requirement of vasoactive drugs (p=0.053)
    • Lower mean number of complications per patient : Cardiovascular(p = 0.03, RR 0.1, 95% CI 0.1-1.0), Infection of uncertain source (p = 0.013, RR not possible), Paralytic ileus (p = 0.001, RR not possible)
    • In patients with complications, intervention reducedrisk of having more than one complication (RR 0.6, but 95% CI 0.3-1.1), but no effect on severity of complications.
    • Reduced length of ICU stay (3 vs 12 days, p = 0.046)

 Conclusions

  • High intensity endurance exercise training is feasible and safe in elderly and/or multimorbid candidates for major abdominal surgery
  • Prehabilitation enhanced clinical outcomes in high-risk candidates for elective major abdominal surgery, which can be explained by the increase in aerobic capacity
  1. Reduced complication rate
  2. Prevents > 1 complication
  3. Reduced ICU length of stay

Strengths

  • Randomised blinded controlled trial
  • High risk patient group selected, reflecting patient population
  • Initially adequately powered
  • Performed within realistic preoperative timeframe for urgent surgery
  • Highly personalised, patient-centred prehabilitation programme. Well detailed for reproducibility
  • Interesting secondary outcomes, validated tools used
  • Appropriate statistical analysis employed
  • Number of patients abandoning intervention arm < control, thus patient engagement good

Weaknesses

  • Single centre
  • Blinding of clinicians following interaction with patients may have been difficult
  • Underpowered following dropouts – still able to demonstrate statistically significant difference in primary outcome, however may have ‘missed’ other significant differences in secondary outcomes
  • ? Blinding of exercise tester
  • Primary outcome extremely broad – ‘any complications’ postoperatively. Not specific, and therefore clinical significance and importance of question reduced.
  • Survival and functional recovery not assessed
  • Underpowered to assess effect on specific and important post operative complications
  • Did not demonstrate a difference in the severity of postoperative complications
  • Claims significant reduction in CV complications and the number of patients having > 1 complication, but:
    • Reduction in CV complications 95% CI 0.1-1, wide and includes ‘no effect’
    • Reduction in number of patients having more than 1 complication 95% CI 0.3-1.1, wide and includes ‘no effect’
  • Endurance time rather than familiar, objective CPEX data e.g. Anabolic threshold, formed basis of measure of aerobic capacity
  • Intensive, highly tailored programme
    • ? Sustainability on larger scale
    • No cost analysis

Implications

  • Prehabilitation in elderly, multimorbid patients appears to be feasible, safe and ‘acceptable’ to patients
  • Prehabilitation can increase preoperative exercise endurance in high risk patients
  • Postoperative complication rates can be reduced by this strategy
  • However, larger trials are required to further characterise and assess the clinical significance of postoperative complication benefits, and to determine the effect on functional recovery and survival

Potential for impact

  • Important step towards assessing the potential benefits and characterising the design of prehabilitation exercise programmes in high risk patients undergoing high risk elective surgery
  • Important and exciting emerging field of research with potential for significantly improving patient outcomes

 

 

 

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