Search

Welsh Anaesthetic Trainees Journal Club

Month

October 2017

Journal Club: 24th October

Emergency Department use of Apneic Oxygenation Versus Usual Care During Rapid Sequence Intubation: A Randomized Controlled Trial (The ENDAO Trial)

Academic Emergency Medicine 2017. Doi:10.1111/acem.13274 (epub ahead of print)

Presented by: Dr S. Young             

Background

  • Desaturation leading to hypoxaemia may occur during rapid sequence intubation (RSI)
  • Preoxygenation is an important part of RSI n order to increase the amount of oxygen present in the functional residual capacity of the patients lungs to prolong the maintenance of acceptable oxygen saturation during the apnoeic period of endotracheal intubation
  • Apnoeic oxygenation was developed with the aim to prevent the occurrence of oxygen desaturation during the apnoea period.
  • It involves leaving the nasal cannulae in place with oxygen flowing during laryngoscopy and intubation.
  • It is being used more and more commonly in emergency and critical care departments.

Design & Setting

A randomised controlled trial based in the emergency department looking at whether apnoeic oxygenation during RSI reduces patient desaturations versus usual care.

Subjects

  • 206 Emergency department patients presenting requiring emergency rapid sequence intubation with preoxygenation for any reason apart from cardiac or traumatic arrest.
  • Based in a level 1 trauma centre in New York.

Intervention

  • Use of high flow oxygen via nasal cannula during the apnoeic period vs no nasal cannula.

Outcomes

  1. Primary: Oxygen saturations were measured by pulse oximetry during and for 2 minutes after the apnoeic period during the RSI. The lowest recorded saturations were taken and the means were compared between the two groups.
  2. Secondary: Desaturations below 90%, 80% and 1st pass success.

Results

  • There was no difference in means of lowest recorded saturations detected between the study groups both 92%.
  • There was also no difference in secondary outcomes.

Conclusions

  • The application of apnoeic oxygenation did not change desaturation in the study population.
  • Its use compared with usual care did not prevent desaturation or reduce the chances of it.

Strengths

  • Well designed study
  • Randomised Controlled Trial
  • Good patient selection and randomisation
  • Relevant study population
  • Good recording of data (trained uninvolved assessors)
  • 100% follow up
  • Real life setting

Weaknesses

  • The trial was not powered highly enough to detect clinically important differences in patient outcome.
  • The primary outcome measured, mean lowest saturations, did not give a patient orientated outcome such as mortality or morbidity.
  • There were very short apnoea times and high first pass success; as such there was very little time for the patients to desaturate.

Implications

The implication is that although this is a negative study it may not have been large enough to detect the patients where apnoeic oxygenation is beneficial.

Even if there had been a statistically significant difference in lowest mean saturations it would have been difficult to read this as a clinically important patient orientated outcome. The trial looked into mortality as a secondary outcome and there was no difference but it was not highly powered enough for this.

Potential for impact

This trial adds to the evidence that there is very little to be gained in most patients with apnoeic oxygenation. It does not however prove that the technique is not useful in some patients.

The paper reviewed earlier this year (see: Journal Club 1st August) suggested that apnoeic oxygenation is a relatively simple and safe intervention with few complications which seemed to be of benefit.

What the ENDAO trial does do is offer evidence that apnoeic oxygenation is not the magic solution to maintaining saturations during RSIs in Emergency department patients. The evidence surrounding apnoeic oxygenation is still not certain and large randomised controlled trials are needed to study this further.

At present we can therefore remain justified in not using this method in our patients.

Journal Club: 17th October

A systematic review of information format and timing before scheduled adult surgery for peri-operative anxiety

Anaesthesia 2017;72:1265-1272

Presented by: Dr J. Niebla-Rodriguez

Background

  • About 25% of patients are anxious and this is associated with pain, poor compliance and harm.
  • Advantages of preoperative information: reduce anxiety
  • Information can be conveyed in different formats: verbal, text, multimedia and in various combinations.
  • Patients retain information that is clear, concise and easy to understand.
  • Different formats of information are more effective to particular people: it depends on age, sex, education, personality and other cultural background.
  • Also when and how the information is conveyed accounts for variation in effect across trials and review.
  • Aim to assess the effects of different formats and timing of pre-operative information on perioperative  anxiety reported by adults.

Design & Setting

  • Standard, quasi and cluster RCT that reported format and timing before scheduled surgery on peri-operative outcomes in any language
  • Information formats : passive / interactive text, audio+ and video  via Person, PC, mobile phone
  • 3 months prior surgery
  • Excluded : studies comparing different information content

TABLE OF PAPERS INCLUDED 

Jesus pic 2

  • 1º outcome = Peri-operative anxiety
  • 2º outcome = patient knowledge and satisfaction with surgery, anaesthesia or information

 

  • 2 reviewers: independently assessed article titles, abstract and full texts
  • Articles were included and rated by 3 reviewers by consensus

The 2 reviewers looked at:

  • Risk of bias, randomisation method, allocation concealment, blinding, completeness of outcome data, selective outcome report and other
  • Risk of bias rated as low or risk unclear in 4 domains: randomisation generation, allocation concealment, incomplete outcome data and selective reporting.
  • They also categorised trial risk of bias as high if risk was gih in any of the 4 domains.
  • No meta-analysis was performed because of disparate  interventions and outcome measure

Network plot: node proportionate to number of trials making the comparison

Jesus presentation

Green, yellow and red : comparisons of low, unclear and high risk bias.

Subjects

3742 Patients undergoing a scheduled operation who were able to understand the language in which the info was presented

Intervention

  • They looked at the various methods and combinations of preoperative information text, verbal, person, multimedia in comparison with the same information in a different format (as listed above) at different time durations before surgery.
  • The information content related to behavioural, procedural and sensory aspects of the patient journey.

Outcomes

  • A: pre-operative anxiety
  • B: postoperative anxiety
  • C: postoperative pain
  • D: length of hospital stay
  • E: participant satisfaction with surgery or anaesthesia
  • F: patient satisfaction with information; g, patient knowledge.

Results

  • 34 trials with 3742 participants : 29 randomised controlled, 4 quasi-randomised and 1 was cluster randomised:
  • The effects of different info formats was assessed by 30 trials.
  • The effects of timing by 5 trials
  • Anxiety was measured using different scoring systems
  • Patient knowledge and satisfaction was analysed by a questionnaire individual to each study so prevented a meta-analysis.
  • The explored the bias in the papers they reviewed
  • Low risk of bias = 6, high risk of bias = 10, 17 stated blinding of participants, personnel and outcome assessors wasn’t possible

Verbal vs text in 4 studies

  • 2 trials no difference in anxiety
  • Verbal inc knowledge and satisfaction in 1 trial, dec knowledge in 2 other studies and no affect in another.

Verbal vs multimedia in 4 studies

  • Multimedia format improved anxiety in 1 study and contradicted in another studies
  • Multimedia formats were superior vs verbal in 3 studies
  • Inc knowledge and satisfaction in 2 studies
  • But inc in mod to severe pain in one study

Text vs multimedia 4 studies

  • 1 study showed no difference in anxiety
  • 2 reported multimedia significantly inc satisfaction with info
  • 1 study reported higher knowledge scores in the same group.

Addition of multimedia to verbal info 6 studies

  • 3 showed no affect on pre-op anxiety
  • 3 showed it improved knowledge
  • 2 showed no difference
  • 1 showed satisfaction with anaesthetics care was unaffected and 1 showed it increase satisfaction
  • 4 trials looked at patient satisfaction with info : 2 showed no effect of multimedia,
  • 3 studies looked the addition of multimedia to verbal and text info : 1 study showed no effect, 1 study showed inc and 1 study showed knowledge respectively. Post op pain and hospital stay was unaffected in two of the 3 studies
  • Knowledge, anxiety and length of hospital stay were unaffected by the addition of multimedia to text in 1 study but showed a dec in anxiety in another.

Addition of text to verbal info in 6 studies

  • 1 showed a dec in anxiety , 2 showed no affect,
  • 4 showed no affect on knowledge and one showed an increase
  • Satisfaction and hospital stay was unaffected

Verbal combined with text or with a multimedia format in 3 studies

  • 2 showed no difference in outcomes of : anxiety, satisfaction with info given, postoperative recall of complications and readability or usefulness of the info.
  • The 3 trial showed that multimedia format increased knowledge and satisfaction.
  • DVDs don’t increase knowledge but don’t affect length of stay.

Effect of timing in 5 studies

  • Timing doesn’t affect pre-op anxiety, post op pain, or hospital stay
  • Post op anxiety was unaffected by timing of direct teaching, or via audiotapes
  • Early text or video info reduced post-op anxiey
  • Knowledge and satisfaction after an interview and video were unaffected by the order in which they were given.

Conclusions

  • They were able to show effects of pre-op info on peri-op anxiety and other outcomes were affected little by format or timing.
  • Similar findings in systematic reviews that included trials of different info content
  • Other systematic reviews didn’t do meta-analyses for the same reasons
  • They want to look at tailoring formats based on personalities
  • Trials should include of poor literacy or computer unfamiliarity

Strengths

  • Robust inclusion and exclusions criteria
  • Bias analysis was ok
  • Explained why they couldn’t do a meta-analysis = too much variation of study designs

Weaknesses

  • No meta-analysis due to heterogenous studies
  • They didn’t know the methodologies of all studies so their assessment of bias was inaccurate
    One of the paper’s editors is the editor of the journal of Anaesthesia but they underwent extended external procedures.

Implications

Some health authorities spend vast resources on multimedia information formats at great cost, but keeping it simple by verbal and written formats could be just as good. Useful in a resource poor environment.

Potential for impact

  • Multimedia formats increase knowledge more than text > verbal.
  • One can incorporate this into our own pre-op assessments:
  • Provide pts with a multimedia reference after they have been to their pre-assessment appointment, or when on the ward, point them towards and app or whilst they wait for their operation if so wish so that we can empower patients in their knowledge of their procedure.

Journal Club: 3rd October 2017

An evaluation of the validity of the preoperative oxygen uptake efficiency slope as an indicator of cardiorespiratory fitness in elderly patients scheduled for major colorectal surgery

Anaesthesia 2017;72:1206-1216

Presented by: Dr S. Churchill

Background

CPEX testing is widely available in preassessment and guiding decision making. Those who have higher cardiorespiratory fitness may have more resilience to metabolic demands of surgical stress. Cardiorespiratory fitness is indicated by peak oxygen uptake and oxygen uptake at anaerobic threshold.

Using CPEX measures peak oxygen uptake and ventilatory anaerobic threshold, however assessing only these measures leads to loss of data. This paper investigates whether we could use submaximal data and extract relevant clinical outcomes. In particular, the paper looks to see if oxygen uptake efficiency slope can be used. The OUES is based on a curvilinear relationship between minute ventilation and oxygen uptake throughout an incremental CPEX test. OUES is thought to be a predictive marker for major cardiac events.

 Methods

This study was conducted in patients over 60 years of age who qualified and who were due to undergo colorectal surgery. Patients had completed a veteran specific activity questionnaire and those who scored <7 METS were recruited.

Those patients who required emergency surgery or who could not complete a CPEX test were excluded. Those patients who consented to the study underwent CPEX testing on an upright bike. The test was considered maximal when patient showed signs of fatigue or when they either reached a HR of>95% predicted or a RER of >1.10.

Data was analysed independently from clinicians performing test. Values at peak exercise were calculated as an average over the last 30s before termination of the test and peak heart rate was that achieved highest during the whole test. A steeper slope represents a higher oxygen uptake efficiency slope and therefore more efficient oxygen uptake (smaller ventilation is required for a given oxygen uptake).

All data collected was used not just 80-90% of the duration of the test which is what occurred in previous studies. Data was adjusted for sex, age, body surface area and body mass and all data was analysed using SPSS.

 Results

  • The study was conducted between Feb 2013 and July 2016.
  • 72 subjects were recruited and they had their CPEX test 26.8 (mean) before their surgery. One further patient was excluded.
  • There was a subgroup analysis between the Anaerobic threshold of >11ml/kg/min and < 11ml/kg/min.
  • OUES showed a statistical difference between OUES100 and OUES80 and OUES90.
  • The data appears more accurate with more data included in analysis.
  • There was a statistically significant correlation between OUES and AT and peak oxygen uptake.

 Limitations of Study

  • This was a single centre study with a small sample size. The data was analysed retrospectively which could lead to bias. There was no sample size pre determined.
  • The study already highlights those who have low METS. Why not a cross spectrum to see if any false positives/negatives?I wonder whether there may be some user error with VSAQ. This questionnaire is  dependent on patients having accurate perception of their own fitness.
  • On CPEX the assessment of maximal testing usses subjective signs of maximal effort, only 76.1% showed the objective signs of maximal effort.
  • Further corrections needed to make some variables statistically significant (Bonferroni)
  • Given that you need all the data to get accurate readings, then maybe the extrapolations wont be so accurate if test you get is submaximal.
  • The results are dependent on the patient having no significant lung disease. This is no relatable to everyday clinical practice.
  • OUES was adapted for body mass….oxygen uptake was not mentioned as being adapted for body mass.
  • At which point do we stop looking at oxygen uptake – up to the plateau or up to point of constant levelling off.
  • Levels associated with risk pre determined in previous studies.
  • No ackowledgement of actual clinical complication in the population deemed to be high risk.

Discussion

  • There are good correlations between OUES and peak oxygen uptake and AT mean it could give us an objective way of assessing cardiorespiratory fitness even in a submaximal exercise test. Data could be extrapolated and AT and peak oxygen uptake could be predicted and could facilitate decision making in high risk patients.
  • Some studies find no difference between maximal and submaximal studies. This one shows that your figures are lower in those in which all data is collected
  • Two patients who had big differences in their OUES100,90 and 80 were excluded and then the data showed no statistical difference between submaximal and maximal tests.
  • There was a strong correlation with peak oxygen uptake and anaerobic threshold is in keeping with other studies.
  • The risk of post-operative morbidity was still correlated to data surrounding AT (<11.1 being high risk). Peak oxygen uptake is still dependent on fatigue and patient effort and therefore results may be submaximal indicator of fitness.

October 2017

Written by Dr C. Williams

Caffeine accelerates recovery from general anesthesia via multiple pathways. Fong R, Khokhar S, Chowdhury A et al. Journal of Neurophysiology 2017;118:1591-1597 doi:10.1152/jn.00393.2017

Currently there is no method to accelerate emergence from general anaesthsia. Patient’s wake when they clear the anaesthetic from their systems. Drugs that had the ability to reverse the coma-like state induced by general anaesthetic agents would likely have considerable utility in clinical settings. In 1975 it was shown that direct intraventricular application of a membrane permeant cAMP analog could accelerate recovery from a variety of anaesthetic and sedative agents.

In 2014 the authors of this study demonstrated that drugs that increase intracellular cAMP dramatically accelerated emergence from anaesthesia. Three intravenous agents that increase cAMP levels were tested – forskolin, theophylline and caffeine – caffeine was shown to accelerate emergence time when anaesthesia was maintained with isoflurane 2%. This study aimed to determine whether caffeine had the same effect at higher anaesthetic concentrations. In this study, rats were anaesthetised for 60 minutes with end-tidal isoflurane levels of 3%. Ten minutes before anaesthesia was terminated the rats were injected with either saline (as a control) or a solution containing caffeine. Recovery time was taken as the time the rat was removed from the anaesthesia chamber, placed on its back on a table to the time it could stand with 4 paws on the table. This study appeared to show that caffeine accelerates emergence from anaesthesia even at high levels of isoflurane. The dose of caffeine was increased by 25mg/kg – starting at 25mg/kg and increasing to 75mg/kg. Caffeine at 75mg/kg produced a 55% reduction in emergence time

Caffeine inhibits phosphodiesterase which prevents the breakdown of cAMP. It also acts as an antagonist at all adenosine receptors. Blockade of the A adenosine receptor mediates caffeine’s arousal effects. Caffeine is already the most psychoactively used drug – in the USA more than 90% of adults use it daily. It is already used clinically either to treat neonatal apnoeas or for certain types of headache and is readily available.

However, this is a small study – no more than 9 rats were studied. There are also questions as to whether this study could be transferred to humans. Also the question as to whether a drug to accelerate emergence is necessary must be raised. It is tempting to speculate about other possible benefits of caffeine. Caffeine is known to have cognitive benefits – hence the reason it is one of the most widely used ‘drugs’. Anaesthetics can impair the cognitive abilities of patients, particularly the elderly, for significant periods of time. If caffeine was shown to accelerate cognitive recovery then it may play a significant role in postoperative recovery. To explore this theory would require extensive research.

Preoperative fluid retention increases blood loss during major open abdominal surgery. Hahn RG, Bahaman H, Nilsson L. Perioperative Medicine 2017;6:12 doi:10.1186/s13741-017-0068-1

Fluid management is an essential component in the management of major abdominal surgery. There is a marked variation in how the kidneys excrete or conserve fluid both in everyday life and preoperatively. Urine analysis can give a measure of the kidney’s state of fluid retention. It is known that a high concentration of urinary waste products is associated with a longer half-life of crystalloid fluid, a greater need for fluid optimisation, more complications after hip fracture surgery and a higher 30-day mortality in acute geriatric care. Little is known about how preoperative fluid retention affects intraoperative fluid balance. The aim of this study was to explore the relationship between preoperative dehydration and fluid requirements during major abdominal surgery with the hypothesis that fluid retention, indicating dehydration would mean more fluid is needed intra-operatively.

Patients undergoing elective open major abdominal surgery had their urine analysed for colour, specific weight, osmolality and creatinine concentration to calculate a fluid retention index. The fluid balance was obtained as the sum of infused fluid (crystalloid, colloid or blood products), minus the blood loss and excreted urine. Fluid retention was found in 37% of patients. It was associated with a significantly higher blood loss, a higher haemorrhage rate and a greater need for intravenous fluids. Despite the larger blood loss, the total fluid balance remained positive after surgery in dehydrated patients.

Preoperative dehydration is associated with higher fluid requirements intra-operatively but also a greater blood loss and a more positive fluid balance. These effects were most apparent in gynaecological and urological surgery. The results from this study would suggest that more fluid should be given to patients found to have concentrated urine preoperatively. More studies are needed to determine if this would improve patient outcome.

Paravertebral block does not reduce cancer recurrence, but is related to higher overall survival in lung cancer surgery: a retrospective cohort study. Lee EK, Ahn HJ, Zo J, Kim K, Jung DM, Park JH. Anaesthesia and Analgesia. 2017 doi:10.1213/ANE.0000000000002342 

Evidence is continuing to emerge about how postoperative analgesic methods have an impact on long-term prognosis after cancer surgery. Opioids trigger immune suppression by impairing innate immunity, altering antigen presentation and predominately favouring pro tumour cytokines. If a patient’s innate immunity is suppressed during the postoperative period there is the potential that remnant malignant cells or micro metastases may grow, establish and spread early after surgery.

Regional anaesthesia can reduce the need for opioids. Using this simple well known fact, it stands to reason that one would expect a lower cancer recurrence and higher survival if regional analgesic techniques were used instead of opioids. This was a large retrospective cohort study aiming to look at precisely this. They hypothesised that thoracic epidural or paravertebral catheters rather than intravenous opioids (via a PCA) as the postoperative analgesic method would be associated with better outcomes in patients undergoing lung cancer surgery.

The notes of 1729 patients undergoing open thoracotomy for primary non-small-cell lung cancer were reviewed. Patients either had a fentanyl PCA, a thoracic epidural with ropivacaine/hydromorphone solution or paravertebral catheter with ropivacaine infusion. Patients had what was then described as a ‘balanced’ anaesthetic  including opioids – either fentanyl boluses or remifentanil infusion. All patients had the same post-operative analgesic protocol for the next 2-3 weeks which was oral analgesics and/or fentanyl patch.

Recurrence rates were similar in all three groups and cancer recurrence was the cause of death in over 80% of the patients in each of the three groups. There was a statistically significant higher overall survival rate in the patients who received paravertebral catheters as the method of post-operative analgesia. Other variables were also related to overall survival including age, male sex, cancer stage, transfusion and duration and extent of surgery.

Unfortunately this study still does not help to answer the questions surrounding the role of anaesthetic techniques on cancer recurrence.

Regional anaesthesia and analgesia in cancer care: is it time to break the bad news? Sekandarzad MW, van Zundert A, Doornebal CW, Hollmann MW. Current opinion in anaesthesiology 2017;30(5):606-612 doi:10.1097/ACO.0000000000000492

The perioperative period is increasingly being recognised as a narrow but crucial window in cancer treatment. As the above paper hypothesises, regional anaesthesia has been proposed to reduce the incidence of cancer recurrence after surgery. There is a separate body of evidence suggesting that perioperative regional anaesthesia may be associated with a survival benefit in cancer patients.

The truth is that existing literature presents conflicting and inconclusive results about the impact of regional anaesthesia on cancer recurrence in patients undergoing surgery. Data is predominantly based on retrospective studies. with as many studies suggesting regional techniques have a positive outcome on cancer recurrence as those that suggest the opposite. The results from meta-analyses and systematic reviews are equally as conflicting. Conflicting results may be due to confounding factors including tumour-specific factors (such as type, grade and lymph invasion) which many studies do not take into account.

It seems unlikely that regional anaesthesia techniques either alone or in combination with modification of other perioperative factors can give clinically meaningful immune-protective effects when powerful chemotherapeutic agents appear to play a small role in cancer survival (contributing to 2% of the 5-year survival in adults). Additionally there is little convincing evidence that opioids promote cancer recurrence or facilitate the development of metastatic disease.

This review article critically refutes the concept that regional anaesthesia as a single modality in the complex oncological setting if cancer surgery can give positive cancer outcomes. The results of ongoing RCTs designed to investigate the link between regional anaesthesia and its ability to reduce cancer recurrence are eagerly awaited although it is unclear as to whether any clear results will be produced. Proving the efficacy of a single intervention (regional anaesthesia) in the multifactorial perioperative oncological setting will be challenging. What is clear is that a reducing postoperative pain and if possible preventing the progression to persistent post surgical pain, even at the expense of no difference in relation to reduced cancer recurrence, is still a goal to aim for.

European guidelines on perioperative venous thromboembolism prophylaxis: Surgery in the elderly. Kozek-Langenecker S, Fenger-Eriksen C, Thienpont E, Barauskas G, for the ESA VTE Guidelines Task Force. European Journal of Anaesthesiology 2017;34:1-7 doi: 10.1097/EJA.0000000000000705

The risk of venous thromboembolism (VTE) is higher in elderly patients particularly those aged over 70 years and elderly patients with co-morbidities. Large population-based epidemiological studies globally show that VTE predominantly occurs in the elderly and rarely occurs prior to late adolescence. But with an increased VTE risk comes an increased risk of bleeding. Therefore it is important to address this issue and ensure that there is appropriate risk stratification, correction of modifiable risks and sustained perioperative thromboprophylaxis.

Limited physiological reserves of older patients make them more vulnerable to postoperative stress and illness including VTE. Factors that have been associated in various studies with deep vein thrombosis and pulmonary emboli in there elderly include: congestive cardiac failure, pulmonary circulation disorders, renal failure, lymphoma, metastatic cancer, obesity, arthritis, post-menopausal oestrogen therapy, anaemia and coagulopathies.

Recommendations for VTE prophylaxis in the elderly are typically extrapolated from non-age specific VTE prophylaxis trials therefore timing and dosing of pharmacoprophylaxis are adopted from the non-aged population.

The general recommendations include:

  • Age over 70 is a risk factor for postoperative VTE
  • In elderly patients identify risk factors and correct if possible
  • Avoid bilateral knee replacements in elderly or frail patients
  • Timing and dosing of pharmacological VTE prophylaxis as in the non-aged population
  • In elderly patients with rena failure, low-dose un-fractionated heparin may be used or weight-adjusted dosing of LMWH
  • Careful prescription of postoperative VTE prophylaxis and early postoperative mobilisation
  • Multi-faceted interventions for VTE prophylaxis in elderly and frail patients including pneumatic compression devices, LMWH (and/or direct oral anti-coagulants after knee or hip replacement)

Risk factors for postoperative ileus after colorectal cancer surgery. Rybakov EG, Shelygin YA, Khomyakov EA, Zarodniuk IV. Colorectal Disease 2017 doi:10.1111/codi.13888

Postoperative ileus is a temporary dysfunction of the gastrointestinal tract in response to surgical intervention. It is a common complication of abdominal surgery and most frequently developed after extensive colorectal operations. It causes significant financial and resource burden on healthcare institutions. The reduction in the incidence of ileus has therefore been placed as one of the top five priorities by the association of coloproctology of Great Britain and Ireland. Treatment is mainly symptomatic as there are no effective pharmacologic agents to treat it, therefore ileus prophylaxis based on the knowledge of potential risk factors is important.

300 patients having elective surgery for colorectal cancer were included. All patients had routine multimodal anaesthesia, a thoracic epidural (with a ropivacaine infusion) and the principles of enhanced recovery were followed: minimal preoperative starvation, no mechanical bowel preparation, no routine use of nasogastric tubes, maintenance of normothermia and minimisation of intraoperative infusions.

Ileus developed in 13% of the patients studied. After multivariate analysis four independent risk factors were identified: a BMI or 26 or over, previous abdominal surgery, the presence of extensive organ adhesions and the administration of opioids in the postoperative period. Importantly due to the fact that every patient in the study had an epidural with a plain ropivacaine infusion only a small proportion (10.7%) required opioids postoperatively. Yet a negative impact of opioids was demonstrated even at this small proportion.

It will never be possible to omit opioids in all patients but actively trying to use techniques that are opioid sparing may be a potential method in which anaesthetists can contribute to reducing the rates of postoperative ileus. This is however a retrospective and relatively small sized study therefore results should be interpreted with some caution.

The impact of fatigue on the non-technical skills performance of critical care air ambulance clinicians. Myers JA, Powell DMC, Adlington S, Sim D, Psirides A, Hathway K, Haney MF. Acts Anaesthesiologica Scandinavia 2017. doi:10.1111/aas.12994

Fatigue and how it affects performance is highly topical at the moment, particularly in anaesthetics following on from the publication of a national survey of the effects of fatigue on trainees in anaesthesia in the UK (Anaesthsia 2017;72:1069-1077) which was reviewed in July’s journal watch.*

This study looked at critical care doctors who are involved in air transfer of patients. The critical care air transport setting is dynamic and challenging and even a small performance decrement has the potential to affect clinical care and patient safety. Fatigue is presumed to negatively influence patient and clinician safety although the precise relationship is not entirely clear. It is also possible that sleep deprived clinicians may not recognise the extent to which their performance is impaired.

Nineteen physicians undertook two different simulated air ambulance missions, once while rested and once when fatigued. Performance was assessed by blinded observers based on expected behaviour in four non-technical skills domains: teamwork, situational awareness, task management and decision making. Participants also rated their own performances. They also completed a psychomotor vigilance task and a cognitive function test.

The physician’s non-technical skills were significantly better across all categories of skills and cognitive tests when rested. Clinicians completed relatively routine air transfer scenarios at levels of fatigue they routinely experience during usual clinical practice (e.g. towards the end of a night shift). Clinician’s also demonstrated limited awareness of their one degraded performance when fatigued. Self-ratings of performance showed no difference between fatigued and non-fatigued performance, in direct contrast to the rating provided by blinded observers.

This study highlights the importance of fatigue and how it can adversely affect performance. There is currently no good policy on recognising and managing the impact of fatigue in the NHS. Hopefully as awareness increases this will be addressed for all healthcare professionals, not only for the impact it has on patient safety but also the long term health impacts of chronic fatigue.

*A national survey of the effects of fatigue on trainees in anaesthesia in the UK. McClelland L, Holland J, Lomas J-P, Redfern N, Plunkett E. Anaesthesia 2017 doi:10.1111/anae.13965

Complications and unplanned admissions in non-operating room procedures. Leslie K, Kave B. Current opinion in Anaesthesiology 2017 doi:10.1097/ACO.0000000000000519 (13)

Increasing numbers of increasingly complex diagnostic and therapeutic procedures are being performed in areas remote from the operating theatre suite. This review aims to look at complications and unplanned admissions in patients requiring anaesthetic care for endoscopy, bronchoscopy and radiology procedures.

For endoscopy large analyses of databases show a low incidence of complications and unplanned admissions. In outpatients the incidence of cardiopulmonary complications was 0.9% – significant predictors included age over 60 years, higher ASA status and inpatient versus outpatient treatment.  Reviews of bronchoscopy seem to show that moderate sedation is tolerated well in these patients. Studies looking at procedures in radiology found that unplanned admissions were more likely to be due to pain, haemorrhage or infection as opposed to a sedation related problem.

Obstructive sleep apnoea has been associated with worse outcomes after procedures in the operating theatre. Studies have shown that OSA in patients having endoscopy or colonoscopy was not associated with any significant increase in cardiovascular or respiratory complications – the authors do make a note that caution should be applied in interpreting this due to poor methodological quality of the studies.

Overall, sedation seems to be associated with a low rate of complications – although some studies suggest more complications during deep propofol-based sedation rather than lighter benzodiazepine sedations. As anaesthetists we would like to think that if we provide the sedation as opposed to it being provided by a non-anaesthetist then it would be safer and have fewer complications. However, studies appear to suggest that sedation provided by anaesthetists is associated with more complications than if given by non-anaesthetists. The reasons for this are not explored but could be related to the fact that anaesthetists may provide sedation for higher risk patients and may provide a deeper level of sedation than non-anaesthetists. Clearly further randomised trials are required to define the optimum sedation drugs, sedation depth and the sedation provider.

Journal Club: 17th July 2017

The SLUScore: A Novel Method for Detecting Hazardous Hypotension in Adult Patients Undergoing Noncardiac Surgical Procedures. 

Anesthesia and Analgesia 2017;124(4):1135–1152. 

Presented by: Dr T. Newton

Background

  • Adequate blood pressure control is one of the major concerns in an intra-operative setting.
  • Increasing evidence that extended periods of severe hypotension may effect long-term outcomes.
  • Patients currently categorised in binary fashion- intervention either unnecessary or already too late.
  • Hypothesis: adverse outcomes affected by severity of hypotension and duration accumulated below thresholds commonly encountered during anaesthesia.

Design and Setting

  • 3 centre retrospective cohort study
  • Approval from institutional ethics bodies
  • Databases searched for adult patients undergoing non-cardiac procedures. Data collected on demographics, Charlson comorbidity score, type of anaesthetic, case duration, blood loss, minute to minute MAP values, all-cause 30 day mortality.
  • Development of score:
    • N=33904
    • Multivariable logistic regression to identify risks associated with increased 30 day mortality including time spent below 31 commonly encountered MAP thresholds
    • % increase in odds of 30d mortality calculated for each minute spent below each of the MAP thresholds
    • Number of minutes calculated for each threshold required to produce identical increases in 30d mortality from 5-30%
    • 20% set used to determine SLUScore- each increment of score corresponds to +5%compounding progression of odds of 30d mortality
  • Validation of score with 3 centre study, n=116,541

Results

  • Independent factors affecting 30 day mortality: age, Charlson comorbidity score, cumulative blood loss. All adjusted for.
  • Dropping below progressively lower MAP thresholds à greater increase in 30d mortality per unit time below that threshld.
  • Preoperative diagnosis of hypertension means time needed below each threshold for same increase in risk.
  • Increase in mortality depended on number of exposure limits exceeded.
  • 30 day mortality approximately doubled in patients with SLUScore >0.
  • Less time may be spent at lower MAP to accrue same risks (analogous to diving charts).

Strengths

  • Large sample size for creation of score, larger size across multiple sites for valifation.
  • 5 year duration at one site.
  • Accounts for some confounding factors, separate scores for pre-existing hypertension.

Weaknesses

  • Does not account for severity/risk of procedure- increased risk of procedure vs MAP, or does procedure cause drop in MAP?
  • Minute to minute measurements taken from extrapolation of 5 minute NIBPs.

Impact

  • Too complex to calculate in real time intra-op.
  • Relies on assumptions with 5 minute NIBPs in most cases.
  • May be useful in future generations of monitors/anaesthetic machines as in-built function.
  • Potential for litigation- if any patient has morbidity from renal function/sepsis etc and has had a GA, anaesthetist may be targeted using SLUScore.

Powered by WordPress.com.

Up ↑