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Welsh Anaesthetic Trainees Journal Club

Month

July 2017

June 2017

Written by: Dr C. Williams

Does the word ‘quiet’ really make things busier? Lam JN, Howard AJ, Marciniak J, Shenolikar A. The Bulletin of the Royal College of Surgeons of England 2017;99(4):133-136 doi:10.1308/rcsbull.2017.133

Many healthcare professionals are remarkably superstitious about saying the ‘Q’ word during a shift. It is a widely held belief that saying the word’ quiet’ will result in a substantial increase in workload. There is no hard evidence to prove this although plenty of anecdotal evidence! The aim of this study was to investigate precisely this idea that saying the word ‘quiet’ has the opposite effect. As the authors point out there is no reason why the principles of evidence-based medicine cannot apply to superstitious practices. This was a multicentre single blind randomized controlled trial. Night sessions were allocated to ‘quiet’ or not at the toss of the coin. This was done by the day orthopaedic registrar just before he attended handover at 8pm. On leaving handover the orthopaedic registrar either said ‘Have a quiet night. I’ll see you in the morning’ or ‘Have a good night. I’ll see you in the morning’. The primary outcome was the number of new referrals between 8pm and 8am that resulted in admission. The results showed that when the word ‘quiet’ was used there were a significantly higher number of admissions during the night-time period. The study suggests that avoiding the word ‘quiet’ could be a cost neutral, clinican-focused method to reduce workload on hosptials and ultimately have an economic benefit………….

Non-technical skills of surgeons and anaesthetists in simulated operating theatre crises. Doumouras AG, Hamidi M, Lung K et al. British Journal of Surgery 2017 doi:10.1002/bjs.10526

In April’s journal watch we looked at a paper which highlighted that teaching of non-technical skills is required at all levels of training including past-fellowship and beyond. This study aimed to look at the impact of non-technical skills in both surgeons and anaesthetists on the time it took to resolve a crisis in theatre. Surgical crises occur in approximately 1.5% of operation. Effective management needs an effective team and collaboration between all team members. Most of the research on non-technical skills has focused on routine operations. As many as 78% of claims highlight non-technical skills with a communication failure being the most common. This was a blinded observational study of surgeon and anaesthetist behaviours during simulated operating theatre crisis scenarions carried out at the Brigham and Women’s Hospital in Boston. The two different scenarios were intraoperative haemorrhage causing haemodynamic instability and a difficult airway resulting in hypoxia and an ultimate need for a surgical airway. Non-technical skills were assessed using the Non-Technical Skills for Surgeons (NOTSS) and Anaesthetists’ Non-Technical Skills (ANTS) rating systems. Surgeons had significantly higher NOTSS scores during the haemorrhage scenario whereas anaesthetists scored very similarly in both. Both groups had significantly higher scores before as opposed to during the crisis. Overall the study found that the most influential predictor of crisis resolution was the ANTS score – as the score increased the time to crisis resolution decreased. Not surprisingly a higher level of non-technical skills (task management, team working, situation awareness and decision making) led to faster crisis resolution. This may be an area where training can be focused for both surgical and anaesthetic trainees.

Randomised clinical trial of comprehensive geriatric assessment and optimisation in vascular surgery. Partridge JSL, Harari D, Martin FC et al. British Journal of Surgery 2017;104(6):679-687 doi:10.1002/bjs.10459

This was a study looking at patients aged 65 and over undergoing vascular surgery specifically elective aortic aneurysm repair or lower-limb arterial surgery. They were randomized to either have a standard preassessment or a preoperative comprehensive geriatric assessment and optimization. The primary outcome was the length of stay with secondary outcomes looking at new medical co-morbidities, postoperative medical or surgical complications, discharge to a higher level of dependency and 30-day readmission rate. The need for comprehensive geriatric assessment is becoming increasingly important as the number of older people undergoing surgical procedures is increasing. We already know that orthogeriatricians can have huge impacts on patient outcome from the work that has been done with orthopaedic and particularly elderly trauma patients. Vascular patients are a known high risk group with multiple risk factors such as smoking, hypertension, hypercholesterolaemia and a significant burden of undiagnosed cognitive impairment, high incidences of delirium, frailty and impaired functional capacity. This study looked at 176 patients – 91 allocated to standard preassessment (control) and 85 to the comprehensive geriatric assessment (Intervention). The mean length of stay was reduced by 40% or approximately 2 days in the intervention group. They also had lower proportions of postoperative delirium, cardiac complications, bladder/bowel issues and trends of lower infection rates and less need for blood transfusion. Having a comprehensive assessment meant that issues such as cognitive disorders, delirium risk, frailty and medical morbities were picked up beforehand. This meant that treatment could be started if needed and an appropriate perioperative plan put in place including longer term follow-up with primary care. These significant findings suggest that comprehensive geriatric preassessment may be of benefit to older patients having elective or emergency surgery across other surgical subspecialties.

Effects of hypercapnia and hypercapnic acidosis on hospital mortality in mechanically ventilated patients. Tiruvoipati R, Pilcher D, Buscher H, Botha J, Bailey M et al. Critical Care Medicine 2017 doi:10.1097/CCM.0000000000002332

Acute respiratory failure is a very common reason for ICU admission and may require invasive mechanical ventilation. With the adoption of lung-protective ventilation strategies to further prevent lung injury in these patients, hypercapnia and hypercapnic acidosis is seen more often. This was a multicentre retrospective study aiming to assess the impact of compensated hypercapnia and hypercapnic acidosis in patients receiving mechanical ventilation. A total of 252,812 patients were included and divided in to three groups – normocapnia and normal pH, compensated hypercapnia and hypercapnic acidosis. The highest mortality was seen in patients with hypercapnic acidosis and particularly hypercapnic acidosis during the first 24 hours of intensive care admission is more strongly associated with increased hospital mortality. The cause of the increased mortality was not clear from this study. Ultimately this study raises more questions and prospective controlled studies are needed to further clarify the effects of hypercapnia and hypercapnic acidosis. But it seems to support the control of carbon dioxide and pH encouraged by low tidal volume ventilation strategies used in the ARDS network study.

The implications of immunisation in the daily practice of paediatric anesthesia. Bertolizio G, Astute M, Angelo P. Current Opinion in Anaesthesiology 2017;30(3):368-375 doi:10.1097/ACO.0000000000000462

Vaccinations in childhood are a remarkable achievement in medical history. This is emphasized by the outbreaks seen in groups of children who are not vaccinated and the effects this can have on society. It is thought that vaccination prevents 2.5 million deaths worldwide each year. For vaccinations to be effective the child needs to develop an effective and antigen-specific adaptive immunity response which requires effective antigen-presenting cells (APCs). APCs consist mainly of monocytes, macrophages, endothelial cells, fibroblasts, fibrocytes and dendritic cells which help to process the antigen and present it to the adaptive immunity B and T lymphocytes. Surgery and anaesthesia are know to be immunosuppressive. There is a theoretical risk of altered responses to vaccines if surgery is performed too close to the time of vaccine administration (either just before or just after). The patient may be prone to vaccine-related complications dues to perioperative immunosuppression, alternatively surgical complications (such as fever or infection) may be misinterpreted as vaccine side-effects. The vaccination schedule is designed in order to maximize the efficiency of the immune system. A previous review in 2006 failed to reach a consensus in the delay of surgery after vaccination. The recommendations made by this paper include:

  1. Postpone and elective procedure that requires anaethesia rather than altering the vaccine schedule
  2. Postpone anaesthesia and surgery for 1 week after an inactivated vaccine is given (diphtheria, tetanus, pertussis, inactive polio, Hib and meningitis C)
  3. Postpone surgery and anaesthesia for 3 weeks after a live attenuated vaccine (measles, mumps, rubella, polio and BCG)
  4. If surgery cannot be avoided regional anaesthesia and the use of synthetic opioids rather than morphine cause less immunosuppression. The patient should be monitored closely after surgery.

Loss of resistance: a randomised controlled trial assessing four low-fidelity epidural puncture simulators. Pedersen TH, Meuli J, Plazikowski E et al. European Journal of Anaesthesiology 2017 doi:10.1097/EJA.0000000000000640

For a successful epidural insertion anaesthetists need to learn two important steps, firstly the correct identification of the epidural space and secondly the correct placement of the epidural catheter. Trainees can struggle with epidurals and it has been quoted that success rates may only be 80% after 90 attempts at epidural. This is lower than success rates for spinals (90% after 71 attempts) and brachial plexus blocks (87% after 62 attempts). Although the traditional way of learning was ‘see one, do one, teach one’ novices ideally now learn the technique on epidural simulators before transferring skills to clinical practice. Epidural simulators are designed to mimic the human lunar spine and usually incorporate an exchangeable puncture block. The price can vary a great deal (€1500 – 3000 is quoted in the paper). The ‘Greengrocer’s Model’ is quoted as an alternative to the epidural simulators – the banana has been described as the most suitable fruit to simulate the loss of resistance feeling. This study aimed to compare three commercially available epidural simulators with a banana. 55 consultant anaesthetists participated and they were blinded to which simulator they were using. They found that while none of the investigated simulators proved to be real substitutes for humans in learning the epidural technique they were useful in learning what a loss of resistance would feel like. Dedicated epidural simulators were statistically significant in providing a more realistic experience than the banana. But the rating were highly variable and the banana was comparable to the simulators in teaching the technique of loss of resistance. If identification of landmarks is not a key part of the simulation (and realistically landmarks can be taught clinically) then the banana may be a reasonable alternative to expensive simulators.

Challenging authority during an emergency – the effect of a teaching intervention. Friedman Z, Perelman V, McLuckie D et al. Critical Care Medicine 2017;XX:00-00 doi:10.1097/CCM.0000000000002450

Communication failures keep coming up as a threat to patient safety and have been the subject of extensive research. We already know that trainees or more junior colleagues are often unable to effectively challenge a senior’s wrong decision particularly during a crisis. This study aimed to assess whether a teaching intervention improved resident’s abilities to effectively challenge clearly wrong clinical decisions made by senior staff. Residents were randomized to either receive targeted teaching on cognitive skills needed to challenge a seniors decision or to receive general crisis management teaching. Two weeks after this teaching, they were put in a simulated crisis of a can’t intubate can’t oxygenate scenario and presented with opportunities to challenge clearly wrong decisions. Residents who had completed the targeted teaching were significantly better able to challenge the wrong decisions in this scenario. However, hierarchy-induced reluctance to speak up remains a major problem with significant implications for patient safety. We must make all trainees understand that it is their responsibility to speak up in these situation. Equally our senior colleagues must embrace open communication from their trainees and other junior colleagues. Senior team members have a responsibility to cultivate an environment in which ALL team members regardless of their training level are encouraged to speak up if they have any concerns.

Should pre-operative optimisation of colorectal cancer patients supersede the demand of the 62 day pathway? Sothisrihari S, Wright C, Hammond T. Colorectal Disease 2017 doi:10.1111/codi.13713

Pre-operative optimization (or prehabilitation) is becoming an increasingly important topic and is gathering momentum. For colorectal surgery, the benefits of thorough optimization before surgery are amplified by the epidemiology and pathophysiology of colorectal cancer. 58% of cases are diagnosed in patients over the age of 70 and in this group the incidence of other significant comorbidities is high. In patients over the age of 80, the post-operative 30-day mortality is 13-15% rising to double that at 60 days. Two-thirds of patients will not return to normal activity and require an increased level of support or package of care on discharge. However, in April 2015 the government in their election manifesto promised to reduce waiting times for cancers and pledged to reduce the current 18 month wait to 18 weeks from referral to operation. Cancer waiting times are now set at 62 days. Are we now doing a disservice to older patients in an attempt to meet targets? The 62-day target does not give the leeway a lot of patients require for proper preoperative optimization. Evidence increasingly suggests we may be doing more harm than good and not addressing risk factors can lead to longer hospital stays, higher infection rates, cardiovascular complications and increased mortality. Maybe the need for prehabilitation should ‘stop the clock’? Often when a full discussion on the reasons for delaying surgery is had with the patient most are happy to participate in prehabilitation. Not all patients require it but the ones that do should be identified with a proper pre-assessment process. As this paper points out this would require a central agreement from policy makers to adjust targets and recognize that sometimes individualized treatment plans correlate with better outcomes.

 

Journal Club: 7th June 2017

Objective model using only gender, age and medication list predicts in-hospital morbidity after elective surgery. Blitz JD, Mackersay KS, Miller JC, Kendale SM. British Journal of Anaesthesia 2017;118(4):5444-5550

Presented by: Dr C. Thomas

Background

  • Recognised need for objective, customised risk evaluation tool for elective surgery
  • For patient and physician
  • Aid informed consent
  • Improve safety by identification of high risk patients
  • Current models require physician input / lab data etc.
  • Aim – objective predictor of inpatient post op morbidity
  • Simple to use
  • Easy to include
  • Simple data – age, gender, list of medications
  • Hypothesis:
  • Gender, age and medication list could provide information about post-operative morbidity
  • Certain medications elevate risk
  • Simplified to number of medications / gender / age

Design and Setting

  • Review board approval – patient consent waived as no intervention mandated
  • Restrospective database study
    • Single centre
    • 2 year period
    • Electronic database (Clarity) – access to ICD-9 codes
    • ASA scores from anaesthetist at time (database)
  • Quaternary Care academic Centre – New York City
    • Large inpatient location, ambulatory locations
    • Patients with mod – high access to healthcare
  • Morbidity outcome was in hospital morbidity by
    • Post op complications – presence of any during admission
    • AF, PE, MI, VTE, CCF, Resp Failure, AKI
  • ICD-9 coding limited – excudes:
    • Haemorrhage, sepsis, cardiac arrest
  • Secondary database created:
    • 46 selected medications – presence or absence each patient (on admission)

Subjects

  • 26629 Adult surgical encounters (>18 years)
  • 02% separate patients, 16.98% >1 surgery/patient
  • Anaesthesia – GA / Regional / Neuraxial / Monitored anaesthesia care
  • Exclusions
    • Emergency surgery
    • No ASA score on database

Intervention

  • Developed predictive models for in hospital morbidity based on outcomes above
  • GAMMA – Gender-Age-Medications Morbidity Assessment
    • Morbidity based on gender, age and medications
    • Logistic regretion based on database
  • ASA-M
    • Morbidity using ASA score as independent variable
  • GAMMA-N –GAMMA-Number modification
    • Morbidity solely on gender age and number of medications
  • Binary logistic regression analyses – assessed for discrimination and power by c-statistic (binary outcomes ie yes or no to condition) – >0.8 indicates strong model.
  • Calibration assessed by Brier score (compares actual events with predicted). Score close to 0 suggests accurate.
  • Chi-Square for model significance.
  • Models developed with full data set and validated with k-fold cross validation – 10 folds.

Outcomes

  • Morbidity Risk from gender, age and medications
  • Morbidity Risk from ASA score
  • Morbidity Risk from gender, age and number of medications

Results

  • GAMMA – predicts post operative morbidity with high accuracy (c statistic 0.819, Brier 0.034)
  • ASA similar (c-statistic 0.827, Brier score 0.033)
  • GAMMA-N less predictive (c-statistic 0.795, Brier 0.050)

Conclusions

  • Authors conclude that combination of age, gender and medication list reliably predict post-operative morbidity.
  • Model has increased objectivity, can be used pre-operatively (lab values etc not required, different to models such as PPOSSUM)
  • Limited medical knowledge required therefore could be patient led.

Strengths

  • Large database
  • Authors recognise limitations
  • Easy to access data – on the whole not subjective (except ASA)

Weaknesses

  • Exclusion of haemorrhage, sepsis and cardiac arrest as complications
  • Other outcomes that patients would consider as morbidity? – very limited number of outcomes studied
  • Patient population – excludes limited resource patients – ? therefore not comparable nationally / internationally or patients not on medications for existing disease due to insurance limitations etc therefore risk may be underscored.
  • Limited list of medications included (46) therefore risk may be underscored for patients on less common or new medications etc. How would this be updated with advances in pharmaceuticals?

Implications

  • Difficult to assess from available information
  • If this tool was studied for other populations and proved accurate it could be implemented as a simple risk stratification tool for elective patients but further study would be required.

Potential for impact

  • Development of a patient led tool for risk assessment – patient led care
  • Pre-operative optimization – reduce their score by improving lifestyle etc to reduce medications
  • Risk stratification for allocation of resources? – such as elective joints requiring lowering of BMI before listed for surgery in some areas.

Journal Club: 2nd May 2017

A randomised double-blind trial of phenylephrine and metaraminol infusions for prevention of hypotension during spinal and combined spinal–epidural anaesthesia for elective caesarean section. McDonnell NJ, Paech MJ, Muchatuta NA, Hillyard S, Nathan A. Anaesthesia 2017;72:609-617

Presented by: Dr K. Kelly

Background

  • Preventing a substantial decrease in maternal blood pressure after spinal anaesthesia for caesarean section is considered fundamental to avoid maternal nausea, vomiting and syncope, as well as neonatal hypoxaemia and acidosis.
  • Maintenance of maternal systolic arterial pressure at near-baseline values has been recommended
  • Metaraminol has undergone limited investigation in obstetric anaesthesia for this purpose, particularly in comparison with phenylephrine.
  • Prophylactic vasopressor administration is commonly recommended to reduce maternal hypotension during spinal anaesthesia for caesarean section.
  • Ephedrine has largely been replaced by phenylephrine, because of improved maternal outcomes and reduced neonatal acidosis when using phenylephrine.
  • Authors hypothesised that use of a prophylactic metaraminol infusion to reduce maternal hypotension would not be inferior to phenylephrine infusion with respect to neonatal acid-base status.

Design and Setting

  • A randomised, double-blind, active control, parallel group, multicentre non-inferiority trial was to compare prophylactic infusions of phenylephrine and metaraminol in women undergoing elective caesarean section under spinal or combined spinal–epidural (CSE) anaesthesia.
  • The study was conducted at between February 2013 and June 2015 in two Australian Hospitals.

Subjects

  • Women of ASA 1–2
  • BMI 20–35 with a singleton term pregnancy,
  • Scheduled for elective caesarean section under spinal or CSE anaesthesia.

Exclusions

  • Diabetes, pre-eclampsia or other cardiovascular or cerebrovascular disease, a foetal abnormality or intra-uterine growth restriction.
  • Inadequate sensory block to cold sensation up to T4.

Outcomes

Primary outcome

  • The primary outcome was the difference in umbilical arterial pH between groups.

Secondary outcomes

  • Other neonatal acid-base measures,
  • Maternal haemodynamic changes.

Interventions

Neuroaxial Technique

  • 2.2– 2.5 ml hyperbaric bupivacaine 0.5% together with 15mcg of fentanyl.

Vasopressors

Commenced at the time of spinal injection.

  1. 30 ml/hr infusion of the study drug, equivalent to 50 mcg/min of phenylephrine (10mg in 100ml)
  2. 250 mcg/min of metaraminol (10mg in 20ml)

Results

  • The mean (SD) umbilical arterial pH was 7.28 (0.06) in the phenylephrine group vs. 7.31 (0.04) in the metaraminol group (p = 0.0002).
  • Apgar scores did not significantly differ between groups.
  • There was a higher incidence of hypotension, defined as systolic arterial pressure < 90% baseline, in the phenylephrine group.
  • There was a higher incidence of hypertension and severe hypertension (systolic arterial pressure > 110% and > 120% baseline, respectively) in the metaraminol group.
  • There was no significant difference between groups in the incidence of nausea, vomiting or maternal bradycardia.

Conclusions

  • There was a higher incidence of hypertension and severe hypertension (systolic arterial pressure > 110% and > 120% baseline, respectively) in the metaraminol group.
  • There was no significant difference between groups in the incidence of nausea, vomiting or maternal bradycardia.

Strengths

  • Well described outcome measures.
  • Well matched groups.
  • Statistical tests clearly outlined.

Weaknesses

  • Large proportion of CSE.
  • BMI may not represent local population.
  • It was conducted during elective surgery in healthy term pregnant women and infants.
  • Findings may not apply to premature infants or to the non-elective setting.
  • Based in two hospitals only

Implications

  • Metaraminol may be a viable alternative if phenylephrine is not available.
  • Use of infusions preferable to bolus dosing to pre –empt the predicted drop in blood pressure due to neuroaxial block.

Potential for Impact

  • Largest clinical trial to compare phenylephrine and metaraminol for the prevention of hypotension during spinal and CSE anaesthesia at caesarean section.
  • Should we move to infusions rather than bolusing?

Journal Club: 18th May 2017

Randomized Clinical Trial Of Preoperative Oral Versus Intravenous Iron In Anaemic Patients With Colorectal Cancer. Keeler BD, Simpson JA, Ng O, Padmanabhan H, Brookes MJ, Acheson AG on behalf of the IVICA Trial Group. British Journal of Surgery 2017;104:214-221

Presented by: Dr D. John

Background

  • Bad things
    • Anaemia – Common – 40% of colorectal cancer patients
  • Adverse associations with blood transfusion
    • Dose independent factors – Expensive, scarce, infection, immunological reactions
    • Dose dependent factors – Biochemical derangements, post-operative infections, length of stay, cancer recurrence, mortality
  • Connected things
    • Pre-operative anaemia and peri-operative blood transfusion
  • Good things
    • Correcting pre-operative anaemia
  • Anaemia in colorectal cancer
    • Almost always due to chronic blood loss
    • Can be corrected with iron therapy
  • Pre-operative recommendations
    • FBC 6 weeks before surgery
    • Oral iron should be first line (ideally until 3 months after restoration of ‘normal’ Hb
      • Cannot be used post-operatively
    • Intravenous iron should be used for those intolerant to oral iron
      • Can be used post-operatively
    • Erythropoetin should not be used (not cost-effective)
  • Peri-operatively
    • Consider transfusion when Hb below 80g/l
    • Give transfusion when Hb below 70g/l
    • Clinical assessment trumps transfusion triggers
    • Transfusion should be by single units
    • Above applies to those with cardiovascular disease

Objectives

  • Determine whether oral iron or intravenous iron is better:
    • At correcting pre-operative anaemia
    • At reducing the need for perioperative blood transfusion

Design and Setting

    • Ethical approval, trial registered
    • Multicentre randomised controlled trial
      • 7 UK sites
      • Transfusion practice in accordance with:
        • Joint UK Blood Transfusion and Tissue Transplantation Services Professional Advisory Committee Guidelines for Surgery

Subjects

  • Patient selection
    • May 2012 – June 2014
    • Colorectal adenocarcinoma
    • Anaemia – ‘to 1g/dl [10g/l] below WHO definition of anaemia of <12g/dl [120g/l] for men and <11g/dl [110g/l] for women’
      • WHO definition of anaemia is 10g/l greater in both sexes – erroneous or poor expression
  • Exclusions
    • Clinical
      • Metastatic disease, pre-existing haematological disease, renal or hepatic failure, chemotherapy, iron contraindications – iron overload, allergy, symptomatic anaemia necessitating transfusion
    • Logistic
      • Children, prisoners, pregnant women, lactating women, women planning pregnancy, previous alimentary tract surgery (>50% of stomach or terminal ileum resected), urgent surgery, previous anaemia not due to colorectal cancer, incapable patients, planned blood donation for surgery, any other significant disease or disorder which may put the patient at risk or influence the trial result (investigator’s opinion), patient unable to comply with study’s requirements (investigator’s opinion), patient unwilling to disclose information to surgeon or GP,

Interventions

  • Randomisation
    • Web-based system
    • Stratified by sex and age
    • Independent of the trial investigaotrs
  • Blinding
    • None

Randomised to:

  • Oral iron
    • Ferrous sulphate 200mg bd until surgery (BNF recommends tds for treatment of anaemia)
  • Intavenous iron
    • Ferinject dosed by Hb and weight (as advised)
    • If two doses required 7 day interval given

How did they go about things?

  • First consultation
    • At least 14 days prior to surgery
    • History, physical examination, randomisation done
    • Iron administration commenced on same day (pre-existing iron supplementation discontinued – investigator should exclude?)
    • If second intravenous dose required then done a week later
  • Peri-operative
    • Pre-operative review (‘around the time of surgery’)
    • Day 2 following surgery
    • Interval reviews until first post-operative clinic (2-3 months usually)
      • End of trial (or if unresectable at surgery, if dead at death, if lost at discharge)
  • At each visit
    • Blood transfusion requirements assessed
      • Volume, date and complications noted
      • Electronic blood bank database and case notes reviewed
    • Hb, ferritin, transferrin saturations
      • Pre-trial and day before surgery
  • Other data recorded
    • Operative blood loss (suction, swab weight), volume and type of intravenous fluid used intra-operatively documented at the time
    • Tumour location, size and grade fom histology report

Outcomes

  1. Primary Outcome – Reduction in perioperative blood transfusion
  2. Secondary outcome – Correction of preoperative anaemia

Results

  • Population
    • Power calculations done – power of 90% of p<0.05
      • Assuming 1 unit difference between groups
      • 116 patients (accounting for drop-outs)
  • Statistics
    • Intention to treat
      • Non-Gaussian paired data used Wilcoxon signed rank
      • Non-Gaussin independent data used Mann-Whitney U
      • Gaussian data used Student’s t
      • Categorical data used Chi-squared
    • P<0.05 was cut off for significance
  • 116 patients
    • 55 to oral therapy
    • 61 to intravenous therapy
    • No demonstrable demographic difference
    • Median time between commencement of therapy and surgery was 21 days in both
    • 11 (6 oral, 5 intravenous) had surgery before 14 days of therapy (3 due to clinical reasons, 8 due to earlier date availability)
    • Median time between surgery and first out-patient appointment was 97 days for oral therapy and 87 for intravenous therpy
  • Adherence
    • Oral therapy by 91%
      • 3% (2 patients) reduced dose due to adverse reaction, 3% increased dose on clinical advice, 3% changed to ferrous fumarate
      • None converted to intravenous therapy
    • Intravenous therapy by 93%
      • 3.5% (2 patients) could not attend second appointment, 3.5% had surgery brought forward
      • 5.5% (3 patients) had post-infusion headache
      • 2% (1 patient) had a rash (oral antihistamines)
  • Cancelled surgery
    • 4 had surgery cancelled due to health decline
    • 1 died during anaesthesia
    • 1 unresectable
  • Blood transfusion (Primary outcome)
    • Pre-operative
      • Oral therapy – 2 patients
    • Intra-operative
      • Oral therapy – 6 patients
      • Intravenous therapy – 6 patients
        • No difference in number transfused (P=0.894)
      • No difference in volume transfused (P=0.863)
    • Post-operative
      • Oral therapy – 14 patients
      • Intravenous therapy – 10 patients
        • No difference in number transfused (P=0.470)
      • No difference in volume transfused (P=0.841)
  • Haemoglobin (Secondary outcome)
    • At recruitment – no significant difference
    • At surgery – significant difference
      • Median rise in oral therapy 5g/l (IQR -1.3 – 13.3), intravenous therapy 15.5g/l (9.3 – 25.8) (P<0.001)
      • Percentage still anaemic in oral therapy 90%, intravenous therapy 75% (P=0.048)
      • Percentage requiring iron therapy in oral therapy 54%, intravenous group 7% (P<0.001)
  • Other measures
    • At surgery
      • Median ferritin level in oral therapy 27.5mcg/l (IQR 17 – 51.5), intravenous therapy 558mcg/l (330-1085) (P<0.001)
      • Median transferrin saturation in oral therapy 9 (IQR 5 – 14), intravenous therapy 19 (16 – 29) (P<0.001)
    • At discharge
      • No difference in length of stay (6 days)
    • Mortality, morbidity, post-operative infection, grade of malignancy
      • No difference

Conclusions

  • Intravenous therapy better than oral therapy
  • No difference in transfusion
  • No difference in morbidity, mortality, length of stay
  • Intravenous iron not inferior
    • No significant adverse reaction

Strengths

  • Randomised controlled trial
  • Multicentre
  • Each centre followed the same transfusion practice in accordance with the Joint UK Blood Transfusion and Tissue Transplantation Services Professional Advisory Committee Guidelines for Surgery
  • Asking a very relevant question

Weaknesses

  • Admitted limitations
    • Lower transfusion rate than expected
      • Higher rate of laparoscopic surgery than previous studies (and consequent lower blood loss)
        • Potential type II error (incorrect acceptance of null hypothesis)
        • Inadequately powered
    • Inadequate duration of therapy prior to surgery
      • Most studies suggest 21 days of therapy is inadequate
      • Would adherence be lower with longer duration of oral therapy in clinical practice?
    • Conflicts of interest
      • Ferinject manufacturer donated drug to most centres and have provided grants, honoraria and travel expenses to many of the paper authors

Implications

  • IV iron probably better than oral
  • Treating anaemia important

Potential for Impact

  • Study not well conducted but may reflect clinical reality
  • Potential for bias significant
  • Probably underpowered

Journal Club: 13th June 2017

Relevance of induced and accidental hypothermia after trauma-haemorrhage – what do we know from experimental models in pigs? Hildebrand et al. Intensive Care Medicine Experimental 2014, 2:16

Presented by : Dr A. Byford-Brooks

Background

  • ‘Lethal triad of trauma’ current model
  • Induced, rather than accidental hypothermia, in animal models has shown potential benefit including:
    • Anti-inflammatory
    • Haemodynamic
    • Reduction of metabolic stress
  • Coagulopathy still a concern
  • Method and technique of cooling could be key

Objectives

  • Benefits/Risks of induced hypothermia
  • Methods of inducing hypothermia
  • Magnitude/Timing/Speed/Duration

Design and Setting

  • Literature review up to July 2013
  • Porcine models of trauma, haemorrhage or combined trauma-haemorrhage
  • Accidental or induced hypothermia
  • Keywords: accidental hypothermia’, ‘spontaneous hypothermia’,‘induced hypothermia’, ‘therapeutic hypothermia’, ‘pigs’, ‘swine’, ‘trauma’, ‘injury’, ‘hemorrhage’, ‘fracture’ and ‘bleeding
  • 36 papers in total

Subjects

  • Porcine models
  • Haemorrhage

1. Controlled à CVC and/or arterial line as %BW

2. +/- Uncontrolled à Surgical insult e.g. Combos of visceral +/- vascular +/- bony trauma

  • Hypothermia

Range:10-35 degrees Celcius (33 deg commonest)

Time: 20mins – 11.5h (2hrs commonest)

Interventions

  • Delay until resuscitation
    • Approximately 0-30s for uncontrolled
    • Approximately 30-40min for controlled
  • Type of resuscitation fluid
    • Crystalloid/colloid (n=19)
    • Blood products (n=3)
    • Combination (n=10)
    • None (n=4)
  • Method of cooling
    • Intraperitoneal packs
    • Cold IVI
    • Cooling blankets
    • Icepacks
    • Roller pump (heparin-free) or CPB (heparin)
  • Method of warming
    • Intraperitoneal lavage
    • Warm IVI
    • Bair hugger
    • Roller pump or CPB
    • No warming

Outcomes

  • Endpoints
    • Mortality
    • Haemostasis
    • Correction of coagulopathy
    • Organ damage e.g. Lactate
    • Use and/or dose of agents being studied e.g. Factor concentrates or haemostatic agents

Conclusions

  • If normothermic – induce hypothermia after primary haemostasis in solid organ damage
  • If accidental hypothermia – correct until haemostats achieved then induce hypothermia (ICU)
  • Rapid cooling better than slow e.g. 2 degrees/min (roller pumps!)
  • Intracorporeal cooling better than extracorporeal (unless also rapid)
  • 34 degrees a good endpoint
  • For aortic trauma – DHCA not more than 60 mins and 10 degrees better than 5 degrees
  • Adequate anaesthesia and relaxation key
  • Rewarming around 0.5 degrees/h
  • No derangements in TEG, coag or Plt between 33-35 degrees
  • Hypothermia reduces plasma levels of inflammatory markers
  • Acidosis in some models due to increased fatty acid vs CHO metabolism and/or slow vs rapid cooling

Strengths

  • Early look at a controversial topic with live subjects
  • Considered multiple models of trauma
  • Compared cooling/rewarming goals and techniques
  • Duration and magnitude of hypothermia

Weaknesses

  • Studies
    • Huge variety in study protocols
    • Circumstances of trauma still artificial and unrealistic
    • Small sample sizes (often <50 total)
    • Type of anaesthesia variable
    • Resuscitation methods (i.e. Crystalloids)
    • Hypothermia often secondary to the study aim
  • Species-specific differences
    • Pigs are hypercoagulopathic compared to humans
    • Acute coagulopathy of trauma (ACOT) has yet to be demonstrated in pigs
    • Despite polytrauma and crystalloid+++, many studies could not induce a coagulopathy
    • Different haemodynamic physiology
  • Long-term effects not investigated
    • Rebleeding
    • Infection
    • Delayed rebound inflammatory response
    • Organ dysfunction on rewarming
    • Posttraumatic apoptosis
  • Subjects with ‘disease states’ not investigated
    • Human population older with comorbidites

Implications

  • Analysis of long-term outcomes not considered
    • Expensive
    • Essentially requires a staffed ICU for the pigs!
  • May lead initially to pragmatic, single-intervention studies on ICU in humans
    • For example in a similar manner to  post-operative cooling in a similar way to out of hospital cardiac arrest or traumatic brain injury
  • Investigation of role of roller pumps in tight thermoregulation and resuscitation

Potential for impact

  • Unlikely to alter current clinical practice with regards to the Lethal Triad
  • However studies suggest mild hypothermia to 34 degrees may not be as deleterious as we think

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