Recommendations for standards of monitoring during anaesthesia and recovery 2021: Guideline from the Association of Anaesthetists.

This guideline updates and replaces the 5th edition of the Standards of Monitoring published in 2015. The aim of this document is to provide guidance on the minimum standards for monitoring of any patient undergoing anaesthesia or sedation under the care of an anaesthetist. The recommendations are primarily aimed at anaesthetists practising in the UK and Ireland, but it is recognised that these guidelines may also be of use in other areas of the world. Minimum standards for monitoring patients during anaesthesia and in the recovery phase are included. There is also guidance on monitoring patients undergoing sedation and during transfer. There are new sections specifically discussing capnography, sedation and regional anaesthesia. In addition, the indications for processed electroencephalogram and neuromuscular monitoring have been updated.

Guidelines for the safe practice of total intravenous anaesthesia (TIVA): Joint Guidelines from the Association of Anaesthetists and the Society for Intravenous Anaesthesia.

Guidelines are presented for safe practice in the use of intravenous drug infusions for general anaesthesia. When maintenance of general anaesthesia is by intravenous infusion, this is referred to as total intravenous anaesthesia. Although total intravenous anaesthesia has advantages for some patients, the commonest technique used for maintenance of anaesthesia in the UK and Ireland remains the administration of an inhaled volatile anaesthetic. However, the use of an inhalational technique is sometimes not possible, and in some situations, inhalational anaesthesia is contraindicated. Therefore, all anaesthetists should be able to deliver total intravenous anaesthesia competently and safely. For the purposes of simplicity, these guidelines will use the term total intravenous anaesthesia but also encompass techniques involving a combination of intravenous infusion and inhalational anaesthesia. This document is intended as a guideline for safe practice when total intravenous anaesthesia is being used, and not as a review of the pros and cons of total intravenous anaesthesia vs. inhalational anaesthesia in situations where both techniques are possible.

Association of Anaesthetists: anaesthesia and peri-operative care for Jehovah's Witnesses and patients who refuse blood.

There are approximately 8.5 million Jehovah's Witnesses and around 150,000 live in Great Britain and Ireland. Based on their beliefs and core values, Jehovah's Witnesses refuse blood component transfusion (including red cells, plasma and platelets). They regard non-consensual transfusion as a physical violation. Consent to treatment is at the heart of this guideline. Refusal of treatment by an adult with capacity is lawful. The reasons why a patient might refuse transfusion and the implications are examined. The processes and products that are deemed acceptable or unacceptable to Jehovah's Witnesses are described. When a team is faced with a patient who refuses transfusion, a thorough review of the clinical situation is advocated and all options for treatment should be explored. After discussion, a plan should then be made that is acceptable to the patient and appropriate consent obtained. When agreement cannot be reached between the doctor and the patient, referral for a second opinion should be considered. When the patient is a child, the same strategy should be used but on occasion the clinical team may have to obtain legal help.

Fibrinogen concentrate vs. fresh frozen plasma for the management of coagulopathy during thoraco-abdominal aortic aneurysm surgery: a pilot randomised controlled trial.

Major vascular surgery is frequently associated with significant blood loss and coagulopathy. Existing evidence suggests hypofibrinogenaemia develops earlier than other haemostatic deficiencies during major blood loss. The purpose of this study was to assess whether the use of an infusion of fibrinogen concentrate to prevent and treat hypofibrinogenaemia during surgery resulted in satisfactory haemostasis, removing or reducing the need for blood component transfusion. Twenty patients undergoing elective extent-4 thoraco-abdominal aortic aneurysm repair were randomly allocated to receive either fresh frozen plasma or fibrinogen concentrate to treat hypofibrinogenaemia during surgery. Coagulation was assessed during and after surgery by point-of-care and laboratory testing, respectively, and treatment was guided by pre-defined transfusion triggers. Despite blood losses of up to 11,800 ml in the patients who received the fibrinogen concentrate, none required fresh frozen plasma during surgery, and only two required platelet transfusions. The median (IQR [range]) allogeneic blood component administration during surgery and in the first 24 h postoperatively was 22.5 (14-28 [2-41]) units in patients allocated to fresh frozen plasma vs. 4.5 (3-11[0-17]) in patients allocated to fibrinogen concentrate (p = 0.011). All patients in both groups were assessed by the surgeon to have satisfactory haemostasis at the end of surgery. Mean (SD) postoperative fibrinogen concentrations were similar in patients allocated to fresh frozen plasma and fibrinogen concentrate (1.6 (0.3) g.l-1 vs. 1.6 (0.2) g.l-1 ; p = 0.36) but the mean (SD) international normalised ratio and activated partial thromboplastin time ratio were lower in patients allocated to fresh frozen plasma (1.1 (0.1) vs. 1.8 (0.3); p < 0.0001 and 1.1 (0.2) vs. 1.7 (0.5); p = 0.032, respectively). Fibrinogen concentrate may be used as an alternative to fresh frozen plasma in the treatment of coagulopathy during thoraco-abdominal aortic aneurysm repair.

Association of Anaesthetists guidelines: cell salvage for peri-operative blood conservation 2018.

The use of cell salvage is recommended when it can be expected to reduce the likelihood of allogeneic (donor) red cell transfusion and/or severe postoperative anaemia. We support and encourage a continued increase in the appropriate use of peri-operative cell salvage and we recommend that it should be available for immediate use 24 h a day in any hospital undertaking surgery where blood loss is a recognised potential complication (other than minor/day case procedures).

The 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: protocol, methods and analysis of data.

Accidental awareness during general anaesthesia with recall is a potentially distressing complication of general anaesthesia that can lead to psychological harm. The 5th National Audit Project was designed to investigate the reported incidence, predisposing factors, causality and impact of accidental awareness. A nationwide network of local co-ordinators across all UK and Irish public hospitals reported all new patient reports of accidental awareness to a central database, using a system of monthly anonymised reporting over a calendar year. The database collected the details of the reported event, anaesthetic and surgical technique, and any sequelae. These reports were categorised into main types by a multidisciplinary panel, using a formalised process of analysis. The main categories of accidental awareness were: certain or probable; possible; during sedation; on or from the intensive care unit; could not be determined; unlikely; drug errors; and statement only. The degree of evidence to support the categorisation was also defined for each report. Patient experience and sequelae were categorised using current tools or modifications of such. The 5th National Audit Project methodology may be used to assess new reports of accidental awareness during general anaesthesia in a standardised manner, especially for the development of an ongoing database of case reporting. This paper is a shortened version describing the protocols, methods and data analysis from 5th National Audit Project - the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home#pt.

The 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors.

We present the main findings of the 5th National Audit Project on accidental awareness during general anaesthesia. Incidences were estimated using reports of accidental awareness as the numerator, and a parallel national anaesthetic activity survey to provide denominator data. The incidence of certain/probable and possible accidental awareness cases was ~1:19 600 anaesthetics (95% CI 1:16 700-23 450). However, there was considerable variation across subtypes of techniques or subspecialties. The incidence with neuromuscular blockade was ~1:8200 (1:7030-9700), and without it was ~1:135 900 (1:78 600-299 000). The cases of accidental awareness during general anaesthesia reported to 5th National Audit Project were overwhelmingly cases of unintended awareness during neuromuscular blockade. The incidence of accidental awareness during caesarean section was ~1:670 (1:380-1300). Two thirds (82, 66%) of cases of accidental awareness experiences arose in the dynamic phases of anaesthesia, namely induction of and emergence from anaesthesia. During induction of anaesthesia, contributory factors included: use of thiopental; rapid sequence induction; obesity; difficult airway management; neuromuscular blockade; and interruptions of anaesthetic delivery during movement from anaesthetic room to theatre. During emergence from anaesthesia, residual paralysis was perceived by patients as accidental awareness, and commonly related to a failure to ensure full return of motor capacity. One third (43, 33%) of accidental awareness events arose during the maintenance phase of anaesthesia, most due to problems at induction or towards the end of anaesthesia. Factors increasing the risk of accidental awareness included: female sex; age (younger adults, but not children); obesity; anaesthetist seniority (junior trainees); previous awareness; out-of-hours operating; emergencies; type of surgery (obstetric, cardiac, thoracic); and use of neuromuscular blockade. The following factors were not risk factors for accidental awareness: ASA physical status; race; and use or omission of nitrous oxide. We recommend that an anaesthetic checklist, to be an integral part of the World Health Organization Safer Surgery checklist, is introduced as an aid to preventing accidental awareness. This paper is a shortened version describing the main findings from 5th National Audit Project - the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home#pt.

The 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: patient experiences, human factors, sedation, consent and medicolegal issues.

The 5th National Audit Project of the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland into accidental awareness during general anaesthesia yielded data related to psychological aspects from the patient, and the anaesthetist, perspectives; patients' experiences ranged from isolated auditory or tactile sensations to complete awareness. A striking finding was that 75% of experiences were for < 5 min, yet 51% of patients (95% CI 43-60%) experienced distress and 41% (95% CI 33-50%) suffered longer-term adverse effect. Distress and longer-term harm occurred across the full range of experiences but were particularly likely when the patient experienced paralysis (with or without pain). The patient's interpretation of what is happening at the time of the awareness seemed central to later impact; explanation and reassurance during suspected accidental awareness during general anaesthesia or at the time of report seemed beneficial. Quality of care before the event was judged good in 26%, poor in 39% and mixed in 31%. Three quarters of cases of accidental awareness during general anaesthesia (75%) were judged preventable. In 12% of cases of accidental awareness during general anaesthesia, care was judged good and the episode not preventable. The contributory and human factors in the genesis of the majority of cases of accidental awareness during general anaesthesia included medication, patient and education/training. The findings have implications for national guidance, institutional organisation and individual practice. The incidence of 'accidental awareness' during sedation (~1:15 000) was similar to that during general anaesthesia (~1:19 000). The project raises significant issues about information giving and consent for both sedation and anaesthesia. We propose a novel approach to describing sedation from the patient's perspective which could be used in communication and consent. Eight (6%) of the patients had resorted to legal action (12, 11%, to formal complaint) at the time of reporting. The 5th National Audit Project methodology provides a standardised template that might usefully inform the investigation of claims or serious incidents related to accidental awareness during general anaesthesia.

5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: protocol, methods, and analysis of data.

BACKGROUND: Accidental awareness during general anaesthesia (AAGA) with recall is a potentially distressing complication of general anaesthesia that can lead to psychological harm. The 5th National Audit Project (NAP5) was designed to investigate the reported incidence, predisposing factors, causality, and impact of accidental awareness. METHODS: A nationwide network of local co-ordinators across all the UK and Irish public hospitals reported all new patient reports of accidental awareness to a central database, using a system of monthly anonymized reporting over a calendar year. The database collected the details of the reported event, anaesthetic and surgical technique, and any sequelae. These reports were categorized into main types by a multidisciplinary panel, using a formalized process of analysis. RESULTS: The main categories of accidental awareness were: certain or probable; possible; during sedation; on or from the intensive care unit; could not be determined; unlikely; drug errors; and statement only. The degree of evidence to support the categorization was also defined for each report. Patient experience and sequelae were categorized using current tools or modifications of such. CONCLUSIONS: The NAP5 methodology may be used to assess new reports of AAGA in a standardized manner, especially for the development of an ongoing database of case reporting. This paper is a shortened version describing the protocols, methods, and data analysis from NAP5--the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home.

5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: patient experiences, human factors, sedation, consent, and medicolegal issues.

The 5th National Audit Project (NAP5) of the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland into accidental awareness during general anaesthesia (AAGA) yielded data related to psychological aspects from the patient, and the anaesthetist, perspectives; patients' experiences ranged from isolated auditory or tactile sensations to complete awareness. A striking finding was that 75% of experiences were for <5 min, yet 51% of patients [95% confidence interval (CI) 43-60%] experienced distress and 41% (95% CI 33-50%) suffered longer term adverse effect. Distress and longer term harm occurred across the full range of experiences but were particularly likely when the patient experienced paralysis (with or without pain). The patient's interpretation of what is happening at the time of the awareness seemed central to later impact; explanation and reassurance during suspected AAGA or at the time of report seemed beneficial. Quality of care before the event was judged good in 26%, poor in 39%, and mixed in 31%. Three-quarters of cases of AAGA (75%) were judged preventable. In 12%, AAGA care was judged good and the episode not preventable. The contributory and human factors in the genesis of the majority of cases of AAGA included medication, patient, and education/training. The findings have implications for national guidance, institutional organization, and individual practice. The incidence of 'accidental awareness' during sedation (~1:15,000) was similar to that during general anaesthesia (~1:19,000). The project raises significant issues about information giving and consent for both sedation and anaesthesia. We propose a novel approach to describing sedation from the patient's perspective which could be used in communication and consent. Eight (6%) of the patients had resorted to legal action (12, 11%, to formal complaint) at the time of reporting. NAP5 methodology provides a standardized template that might usefully inform the investigation of claims or serious incidents related to AAGA.

5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors.

We present the main findings of the 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia (AAGA). Incidences were estimated using reports of accidental awareness as the numerator, and a parallel national anaesthetic activity survey to provide denominator data. The incidence of certain/probable and possible accidental awareness cases was ~1:19,600 anaesthetics (95% confidence interval 1:16,700-23,450). However, there was considerable variation across subtypes of techniques or subspecialities. The incidence with neuromuscular block (NMB) was ~1:8200 (1:7030-9700), and without, it was ~1:135,900 (1:78,600-299,000). The cases of AAGA reported to NAP5 were overwhelmingly cases of unintended awareness during NMB. The incidence of accidental awareness during Caesarean section was ~1:670 (1:380-1300). Two-thirds (82, 66%) of cases of accidental awareness experiences arose in the dynamic phases of anaesthesia, namely induction of and emergence from anaesthesia. During induction of anaesthesia, contributory factors included: use of thiopental, rapid sequence induction, obesity, difficult airway management, NMB, and interruptions of anaesthetic delivery during movement from anaesthetic room to theatre. During emergence from anaesthesia, residual paralysis was perceived by patients as accidental awareness, and commonly related to a failure to ensure full return of motor capacity. One-third (43, 33%) of accidental awareness events arose during the maintenance phase of anaesthesia, mostly due to problems at induction or towards the end of anaesthesia. Factors increasing the risk of accidental awareness included: female sex, age (younger adults, but not children), obesity, anaesthetist seniority (junior trainees), previous awareness, out-of-hours operating, emergencies, type of surgery (obstetric, cardiac, thoracic), and use of NMB. The following factors were not risk factors for accidental awareness: ASA physical status, race, and use or omission of nitrous oxide. We recommend that an anaesthetic checklist, to be an integral part of the World Health Organization Safer Surgery checklist, is introduced as an aid to preventing accidental awareness. This paper is a shortened version describing the main findings from NAP5--the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home.

A novel technique to determine an 'apparent ke0 ' value for use with the Marsh pharmacokinetic model for propofol.

Debate continues over the most appropriate blood-brain equilibration rate constant (ke0) for use with the Marsh pharmacokinetic model for propofol. We aimed to define the optimal ke0 value. Sixty-four patients were sedated with incremental increases in effect-site target concentration of propofol while using six different ke0 values within the range 0.2-1.2 min(-1). Depth of sedation was assessed by measuring visual reaction time. A median 'apparent ke0' value of 0.61 min(-1) (95% CI 0.37-0.78 min(-1)) led to the greatest probability of achieving a stable clinical effect when the effect-site target was fixed at the effect-site concentration displayed by the target-controlled infusion system, at the time when a desired depth of sedation had been reached. By utilising a clinically relevant endpoint to derive this value, inter-individual pharmacokinetic and pharmacodynamic variability may be accounted for.

Induction of general anaesthesia by effect-site target-controlled infusion of propofol: influence of pharmacokinetic model and ke0 value.

We studied the use of a new ke0 value (0.6 min(-1)) for the Marsh pharmacokinetic model for propofol. Speed of induction and side-effects produced were compared with three other target-controlled infusion systems. Eighty patients of ASA physical status 1-2 were studied in four groups in a prospective, randomised study. Median (IQR [range]) induction times were shorter with the Marsh model in effect-site control mode with a ke0 of either 0.6 min(-1) (81 (61-101 [49-302])s, p < 0.01), or 1.2 min(-1) (78 (68-208 [51-325])s, p < 0.05), than with the Marsh model in blood concentration control (132 (90-246 [57-435])). The Schnider model in effect-site control produced induction times that were longer (298 (282-398 [58-513])s) than those observed with the Marsh model in blood control (p < 0.05), or either effect-site control mode (p < 0.001). There were no differences in the magnitude of blood pressure changes or frequency of apnoea between groups.

Long-term renal outcomes of consecutive patients undergoing open type IV thoracoabdominal aneurysm repair.

OBJECTIVE: To evaluate long-term renal outcomes after open type IV thoracoabdominal aneurysm (TAAA) repair. DESIGN: Retrospective analysis of a prospectively collected database of consecutive operated non-ruptured type IV TAAAs (2007-2011). METHODS: Renal function was analysed by serum creatinine concentration, estimated glomerular filtration rate (eGFR) and Kidney Disease Outcomes Quality Initiative (KDOQI) stage. The primary outcome was the change in creatinine concentration from before surgery to defined time points after surgery: peak postoperative; discharge; at follow-up (>1 year postoperatively). Secondary outcomes were change in eGFR, change in KDOQI stage, dialysis requirement, and 30-day mortality. RESULTS: Between 2007 and 2011, 53 open type IV TAAA repairs were performed. Median creatinine levels significantly increased in the immediate postoperative period, but returned to baseline by discharge. Thirteen patients (28.2%) had an improvement in follow-up eGFR of at least 20% compared with pre-operative eGFR or improved by one KDOQI stage. Twelve patients (26.1%) had a decline in eGFR of at least 20% or one KDOQI stage at follow-up. Three patients (7.5%) required temporary dialysis and one patient (1.9%) required permanent dialysis. The 30-day mortality was 1.9%. CONCLUSIONS: This study demonstrates acceptable renal outcomes following open type IV TAAA repair. Open type IV repair remains the standard against which newer techniques should be compared.

Platelet activation in patients with peripheral vascular disease: reproducibility and comparability of platelet markers.

BACKGROUND: Many markers of platelet activation have been described but their reproducibility and comparability in patient populations are poorly defined. OBJECTIVES: We sought to compare markers of platelet and monocyte activation with platelet-monocyte aggregates, a proposed gold standard of in vivo platelet activation, and assess their reproducibility in patients with peripheral arterial disease: a population with substantial platelet activation, inflammation and risk of thrombotic events. PATIENTS/METHODS: Thirty patients with peripheral vascular disease attended on two occasions to permit within-day and between-day comparisons. In vivo platelet and monocyte activation were determined by flow-cytometric quantification of platelet-monocyte aggregation, platelet surface expression of P-selectin and CD40L, platelet-derived microparticles, and monocyte surface expression of CD40 and CD11b. Plasma concentrations of platelet-derived microparticles, soluble P-selectin and CD40L were measured by enzyme-linked immunosorbant assays. RESULTS: Platelet-monocyte aggregation (36.7±7.86%), and platelet surface expression of P-selectin (5.8±1.65%) and CD40L (3.3±1.45%) demonstrated comparable within-day (mean difference±co-efficient of reproducibility; 0.9±15.4%, 0.21±1.65% and 0.2±2.8% respectively) and between-day reproducibility (2.0±12.4%, 0.10±2.25% and 0.9±6.4% respectively). Platelet-monocyte aggregates correlated well with other platelet (r=0.30-0.50, P<0.02) and monocyte (r=0.27-0.47, P<0.03) activation markers. Flow cytometric and assay quantified platelet-derived microparticles showed poorer reproducibility (co-efficient of reproducibility >40). CONCLUSIONS: In patients with peripheral arterial disease, measurements of platelet-monocyte aggregates have good reproducibility and consistently reflect other markers of platelet and monocyte activation.

The effect of anaesthesia and aortic clamping on cardiac output measurement using arterial pulse power analysis during aortic aneurysm repair.

The LiDCO plus monitor (LiDCO Ltd, Cambridge, UK) uses pulse contour analysis of the arterial pressure waveform to indicate changes in stroke volume and cardiac output. Calibration against a lithium indicator dilution method is required to permit display of absolute values in addition to trends. The effect of haemodynamic changes during anaesthesia and surgery on this calibration factor has not previously been studied. Therefore, we investigated whether it remained constant during elective abdominal aortic aneurysm surgery in 15 patients. Comparison between the calibration factor values at different time points was made by repeated recalibration throughout the peri-operative period. Calibration factor increased by a mean of 53% after anaesthesia (epidural plus general) (p = 0.03) and decreased by a mean of 40% after aortic clamping (p = 0.0001). Recalibration should be undertaken after induction of anaesthesia and after aortic clamping if absolute values of cardiac output and stroke volume are required.

Contemporary results for open repair of suprarenal and type IV thoracoabdominal aortic aneurysms.

BACKGROUND: Endovascular and hybrid procedures are not yet widely established in the management of type IV thoracoabdominal aortic aneurysm (TAAA). Open surgery remains the treatment of choice until the long-term outcomes of these novel techniques are known. METHODS: This study reviewed a 10-year experience of open repair of non-ruptured type IV and suprarenal TAAA. All procedures were performed using a totally abdominal approach with supracoeliac clamping of the aorta. RESULTS: There were 53 patients (31 men; 58 per cent) of median age 69 (range 54-82) years. Forty-four patients had a type IV TAAA and nine a suprarenal aneurysm. Three patients (6 per cent) died within 30 days and the 12-month mortality rate for patients followed for at least 1 year was 6 per cent (three of 49). Ten patients (19 per cent) had a cardiac complication, 20 (38 percent) a respiratory complication, three (6 percent) required early reoperation, and one patient (2 percent) developed permanent paraplegia. There was one late death resulting from an aneurysm-related complication. CONCLUSION: Open repair of suprarenal aneurysms and type IV TAAA may be undertaken using a totally abdominal approach with acceptable levels of morbidity and mortality.