Anaesthesia and Intensive Care

Venous thromboembolism (VTE), encompassing deep vein thrombosis and pulmonary embolism, contributes significantly to morbidity and mortality in critically ill patients. This increased incidence is influenced by factors such as indwelling central venous catheters, continuous sedation, and vasoactive infusions, in addition to traditional VTE risk factors such as immobility. Optimal VTE prophylaxis remains uncertain owing to significant variability with regard to differences across existing randomized controlled trials (RCTs) in terms of patient populations, types and dosing of prophylactic interventions, and definitions of VTE outcomes. RCTs conducted on critically ill patients are often limited by over-optimistic estimates of baseline event rates and potential treatment benefit. We conducted a systematic review to evaluate the described sample size methodologies and justification amongst VTE-prevention RCTs for critically ill patients. We searched MEDLINE and Embase from inception until 9 September 2024, and included 12 RCTs enrolling 9154 patients. Sample sizes ranged from 36 to 3746 participants. Only six studies met their recruitment targets, while four did not report a sample size calculation. Among the seven studies that reported an estimated control event rate, only one met that estimate. No studies achieved their planned absolute risk reduction, and only one met its relative risk reduction target. Prognostic enrichment strategies were employed in 41.6% of trials, while predictive enrichment was rarely used. These findings suggest that intensive care unit VTE prophylaxis trials frequently overestimate baseline risk and treatment effect size, contributing to underpowered studies and potential premature abandonment of promising interventions. Future trials should incorporate enrichment strategies and justify assumptions based on clinical relevance and patient-centred outcomes.

Single-use items in pre-packaged procedure packs are disposed of after opening, regardless of whether they were used. We aimed to synthesise published evidence on evaluations of hospital-relevant interventions or comparisons targeting waste from procedure packs. We included intervention and aetiological observational studies, excluding purely descriptive studies, secondary studies and conference abstracts. We searched MEDLINE, Embase, CINAHL and Scopus from inception to 7 May 2024 and undertook forward and backward citation searches of included records. Of 1074 records retrieved, 14 studies met inclusion criteria. Eight were before–after quality improvement studies, five were comparative life cycle assessments and one was an audit. Studies reported on reductions in items in the pack (n = 8), change from single-use to reusable items (n = 3) and comparisons between different packs (n = 2) or individually packed items and packs (n = 1). Twelve studies reported on financial and waste impacts, six on environmental impacts and three on staff/patient impacts. Studies reported financial savings up to US$49.43 for reduced item packs and up to £7.22 for reusable packs versus single-use packs. Pack size and weight can often be much reduced, leading to less resource use and up to 2042g reduction in waste/pack and up to 860g less CO₂ equivalent (CO₂e) emissions. Switching instruments in packs from single-use to reusable reduced emissions by up to 90% where local energy was not predominantly from fossil fuels. No negative impacts on staff or patient outcomes were reported. Initiatives to reduce waste from single-use procedure packs may result in significant financial, resource use and CO₂e emissions savings.

Hospitals, and in particular operating theatres, contribute significantly to the carbon footprint of modern healthcare. Operating theatres account for a large part of hospital waste, which can be offset by using more reusable or recyclable equipment. However, environmentally sustainable decisions within healthcare need to be evaluated to ensure they can be introduced without a negative impact on patient safety or outcomes. We performed a systematic review and meta-analysis to evaluate the difference in the rates of microbiological contamination of anaesthetic breathing circuits between single day or extended (more than one day) use in the provision of general anaesthesia in adult patients, where a microbial filter was used and changed for each patient regardless of the duration of breathing circuit usage. The results demonstrate no significant increase in the rate of contamination between single day and extended use breathing circuits (odds ratio (OR): 0.84; 95% confidence interval (CI): 0.44 to 1.60) or single day and seven-day breathing circuits (OR: 1.30, 95% CI: 0.34 to 4.97). This supports the use of extended use breathing circuits for up to seven days for both the demonstrated environmental and financial benefits, with no evidence of compromise to patient safety.

Remifentanil and dexmedetomidine are sedative agents used both in anaesthetic and critical care practice. Their effects on the gastro-oesophageal pressure gradient and hence on the potential risk for regurgitation have not been quantified. The aim of this study was to measure and compare the effects of both agents on the gastro-oesophageal pressure gradient. The study used a randomised, double blinded crossover study design, and 16 healthy volunteers were sedated on two separate occasions. Baseline lower oesophageal sphincter pressure (26 and 28 mmHg for dexmedetomidine and remifentanil, respectively) and gastro-oesophageal pressure gradient (20 mmHg for both dexmedetomidine and reminfentanil) were recorded. Then, each volunteer received increasing doses of target-controlled infusions of dexmedetomidine (1, 2, 4, 6 ng/ml) or remifentanil (1, 2, 3, 4 ng/ml). Each dose level was maintained for 20 minutes, and both lower oesophageal sphincter pressure and gastro-oesophageal pressure gradient were continuously recorded. Measurements were averaged. Out of 16 subjects recruited, data were analysable from 11 (aged 18–54 years, body mass index 17.7–27.9 kg/m², five men and six women). The dose regimens of both agents provided similar profiles of progressive sedation over time, with sedation scores reaching a minimum of −2 on the ‘observer’s assessment of alertness and sedation score’ with both medications. With dexmedetomidine, the bispectral index gradually decreased in line with sedation scores (P<0.05), but remifentanil produced little change in the bispectral index from baseline. Both agents decreased gastro-oesophageal pressure gradient (P<0.001) similarly, (P=0.199), in line with the decreases in sedation scores. In conclusion, when remifentanil or dexmedetomidine are administered to provide sedation they induce similar decreases in gastro-oesophageal pressure gradient. This may put patients at comparable risk of gastro-oesophageal reflux.

The preoperative risk score and key recommendations designed by the National Emergency Laparotomy Audit (NELA) have resulted in improved outcomes for patients undergoing emergency laparotomy. However, the recommended routine intensive care/high dependency unit (ICU) admission for high-risk patients is not always logistically possible and predictive models are needed to identify patients who will benefit. We conducted a study of patients undergoing emergency laparotomy at our tertiary hospital in Western Australia between 2018 and 2023 to identify factors that were associated with the need for ICU admission after emergency laparotomy, as defined by the requirement for a vasopressor infusion, continuous renal replacement therapy or ventilation. Of 1100 patients identified, 875 were included in the primary analysis. In multivariate analysis, the only independent predictive factors of the need for ICU therapies were the American Society of Anesthesiologists grade (P=0.017) and peak intraoperative serum lactate concentration >2 mmol/L (P=0.038). An increased NELA score was associated with mortality; however, it was not associated with the requirement for any ICU therapy (P=0.993). Although only 35.8% of high-risk patients were admitted to ICU, there was no apparent increase in adverse outcomes including mortality or unexpected ICU admission, and 27.4% of patients that were admitted to ICU received no specific therapies. This study provides a basis for the development of new predictive models for ICU admission post emergency laparotomy, and suggests the possibility that routine elective admission might not necessarily add value beyond that achieved by other NELA standards.

Little is known about the characteristics of potentially inappropriate or unnecessarily prolonged intensive care unit (ICU) admissions in Australia, nor the exposure rate of non-ICU clinicians to dying ICU patients. We conducted a single-centre retrospective cohort study at a university-affiliated hospital in Victoria, Australia, of patients admitted to the ICU between January 2022 and June 2023, who transitioned to end-of-life care during their ICU admission. Decisions regarding appropriateness were adjudicated during a bi-weekly morbidity and mortality meeting. Out of 287 patients 279 were included in the final analysis. One hundred and eight (39%) patients were deemed to have had a potentially inappropriate admission, and 37 (13%) were deemed to have had a potentially inappropriately prolonged admission. Significantly higher proportions of patients were admitted from either the ward (32.4% versus 22.4%, P=0.02) or another hospital (15.7% versus 6.4%, P=0.02) if they were deemed to have had a potentially inappropriate admission. Significantly higher proportions of patients deemed to have had a potentially inappropriately prolonged admission had treatment limitations (16.2% versus 40.5%, P=0.006), lower Australian and New Zealand Risk of Death scores (median score 27.2 versus 45.5, P=0.006) and a clinical frailty score of 5 or more (63.9% versus 45.1%, P=0.048). They also had a significantly longer median ICU length of stay (median length of stay 13.4 days versus 2.6 days, P <0.001) and received significantly higher rates of invasive supports such as tracheostomy (16.2% versus 1.2%, P <0.001). The four major themes linked to these admissions were 1) lack of planning/appropriate treatment limitations, 2) lack of recognition of dying, 3) issues with communication/consensus and 4) provision of highly invasive treatments. The median rate of exposure of individual ward-based clinicians was 1 dying ICU patient per 18 months. Early framing of goals of care, reassessment of treatment goals during an ICU admission, dedicated communication skills training, and embedded frailty assessments might reduce non-beneficial and prolonged ICU admissions.

Post-procedural residual neuromuscular paralysis is an uncommon but serious complication in the general surgical population. Whilst the incidence of post-procedural residual neuromuscular paralysis in the general surgical population has been widely reported, there are no published data on the definition or incidence of this complication in patients undergoing electroconvulsive therapy (ECT). In our single-centre, prospective observational audit we studied the incidence of residual neuromuscular blockade following ECT between January and April 2021. Out of 25 procedures carried out over this time period, 23 were included for analysis. A total of 14 patients (61%) left the ECT suite with potentially clinically significant residual neuromuscular blockade. The median suxamethonium dose was 0.83mg/kg (interquartile range 0.68–0.91). Despite the known complications resulting from post-procedural residual neuromuscular blockade, neuromuscular monitoring is not mandated in guidelines published by the Australian and New Zealand College of Anaesthetists or the American Society of Anesthesiologists. Our preliminary findings suggest that further research into the scope and significance of residual neuromuscular blockade following ECT is warranted.

This case report describes the management of a patient with a lumbar arachnoid cyst requesting epidural labour analgesia. The patient was otherwise healthy but had suffered from multiple dural punctures during attempted epidural placement in a previous pregnancy. Magnetic resonance imaging following the dural punctures revealed the cyst, which was at the level of the L3–4 interspace, effacing the posterior epidural space at that level. Multidisciplinary management in this subsequent pregnancy, involving radiology and anaesthesia specialists, allowed ultrasound-guided identification of a higher epidural space, and successful and uneventful epidural placement during labour. Multiple dural punctures with attempted epidural placement should prompt anaesthetists to consider spinal magnetic resonance imaging to identify anatomical abnormalities that may be present, which may have implications for future management.

Prekallikrein deficiency is a rare autosomal recessive coagulation disorder that prolongs the activated clotting time. Guidelines for safe intraoperative coagulation control in patients with prekallikrein deficiency undergoing endovascular aortic repair are limited. We present a case of a 70-year-old man with prekallikrein deficiency who underwent endovascular aortic repair and required intraoperative anticoagulation control. Intraoperative anticoagulation with heparin and protamine was successfully managed using the activated clotting time measurements after preoperative administration of two units of fresh frozen plasma for prekallikrein replenishment. Preoperative prekallikrein replenishment by fresh frozen plasma administration contributed to safe intraoperative anticoagulation management.

Postoperative pain management in breast cancer surgery remains challenging, particularly in procedures involving submammary tissue expander placement, where patients often report inadequate pain control. The complex innervation of the breast region, involving intercostal nerves (T2–T6), brachial plexus branches, and supraclavicular nerves (C3–C4), necessitates comprehensive anaesthetic coverage. We present four cases utilising a novel combined approach of erector spinae plane (ESP) and serratus posterior superior interfascial plane (SPSIP) blocks for perioperative pain management. The technique involves ultrasound-guided administration of ropivacaine 0.25% (20 ml for each block) targeting the T3 level for ESP and the fascial plane between the second and third ribs for SPSIP. This combination provides extensive hemithoracic analgesia from C3 to T10, potentially covering both superficial and deep tissue components of surgical pain. Our cases demonstrated excellent postoperative pain control with minimal analgesic requirements. The proximity of injection sites allows efficient block performance without patient repositioning. This additive approach shows promise in achieving comprehensive analgesia for breast surgery, including cases involving tissue expanders, though larger targeted studies are needed to confirm these preliminary findings.

A woman in her early sixties presented to the emergency department with an altered level of consciousness and severe hypertension (blood pressure 197/111 mmHg) on a background of Grave’s disease, osteoporosis and hypertension. She was intubated following prolonged seizure activity attributed to critical hyponatraemia (serum sodium 108 mmol/L). Abnormal renal function (estimated glomerular filtration rate 51 ml/min per 1.73m²) was also identified on admission. She was transferred to the intensive care unit for further investigation and management of hypertension and hyponatraemia, where she made an excellent recovery and a unifying diagnosis of bilateral renal artery stenosis was made. Renal artery stenosis has been previously described with chronic and unilateral presentations not requiring intensive care support. This case report describes the pathophysiology of this previously unreported presentation of severe symptomatic hyponatraemia and hypertension due to bilateral renal artery stenosis and the challenges faced in intensive care to determine the diagnosis.