Journal Watch: April 2022
Real-Time Ultrasound-Guided Versus Ultrasound-Assisted Spinal Anesthesia in Elderly Patients With Hip Fractures: A Randomized Controlled Trial
Edited by Aoife Lavelle
This prospective, randomised trial compared the performance of spinal anaesthesia on elderly patients with hip fractures undergoing surgical repair using pre-procedural US-assisted (USAS) landmark identification and the more novel real-time ultrasound-guided (USRTG) technique.
Elderly patients with hip fractures needing spinal anaesthesia present a significant clinical challenge due to lumbar degeneration and positioning limitations. Pre-procedural USAS identification of the spinal anatomy has been shown to improve puncture success rate, reduce needle passes and procedural time and increase the procedure's safety.1 While USRTG guidance allows observation of the needle during needle insertion. The authors proposed USRTG spinal anaesthesia as a novel technique to improve the first-attempt success rate of spinal anaesthesia when compared with pre-procedural USAS landmark identification.
This was a prospective randomised trial. 114 patients were recruited over 6 months. All blocks were performed by 1 of 3 consultant anaesthesiologists skilled in US-guided blocks. All patients received an US-guided fascia iliaca compartment block 15 minutes before positioning. No sedatives were administered before or during the puncture procedure. The USAS group received spinal anaesthesia via the paramedian approach at the optimal puncture point as dictated by pre-procedural scanning. In the USRTG group, US was used to identify the midline and the widest intervertebral space. 1 of 3 approaches was used for spinal anaesthesia in this group: paramedian sagittal in-plane, paramedian sagittal out-plane or paramedian transverse in-plane.
The primary outcome was the first-attempt success rate of spinal anaesthesia, defined as successful dural puncture through a single attempt. Secondary outcomes included first-pass success rate (no redirection required during the first attempt), number of attempts & passes, time taken to locate and mark anatomy, time taken to perform spinal anaesthesia, total procedural time, adverse reactions or complications, patient satisfaction and procedural difficulty.
The sample size calculation was based on a pilot study which found USAS and USRTG to have a 76% and 43% first-attempt success rate, respectively. 45 patients were required for each group at the 0.05 significance level and 90% power; this was increased to 57 patients per group to allow for dropout.
The first-attempt success rate was higher in the USAS group than the USRTG group (80.6% vs. 52.6%), while first-pass success rate was 63.2% and 31.6%, respectively. Total number of attempts and passes was significantly lower in the USAS group. While USAS took longer to locate and mark the anatomy than USRTG, USAS took less time to perform spinal anaesthesia and its total time was shorter. Patient satisfaction scores were higher in the USAS group, while procedural difficulty scores were higher in the USRTG group. No significant difference in complications or adverse reactions was noted between the groups. No patients in the USAS group required a switch in technique to acquire CSF, whereas 8 patients in the real-time group did. No patients in either arm of the study required conversion to general anaesthesia.
So what does this mean for our practice?
Even in the hands of skilled sonographers, there does not appear to be an advantage to using real-time US-guidance for spinal anaesthesia. The role of US in spinal anaesthesia appears to be limited to assisting in pre-procedural landmark identification.
A. J. Wickham, D. T. Highton, S. Clark, D. Fallaha, D. J. N. Wong and D. S. Martin on behalf of the Research and Audit Federation of Trainees
Edited by Dr Kim Caulfield
iHypes main hypothesis is that the majority of older patients in the UK experience intra-operative hypotension below consensus defined thresholds (MAP <65mmHg, <20% decrease in systolic BP or SBP <100mmHg). The main concern with intra-operative hypotension is its association with myocardial injury, acute kidney injury, stroke and death. Intra-operative hypotension is increasingly implicated in the pathogenesis of perioperative end organ dysfunction most likely secondary to hypoperfusion and ischaemia.
This observation study was designed and carried out by the Research and Audit Federation of Trainees. It was a nationwide collaborative research effort. Ethical approval was sought from the West London and Gene Therapy Advisory Committee Research Ethics Committee. All patients aged >/=65years undergoing general or regional anaesthesia in the UK were enrolled into the study during a 48hour time period during a 4-week period between November and December 2016. Patients who were enrolled were followed for 30 days post-surgery.
Primary Outcome – incidence of intra-operative hypotension: MAP <65mHg, SBP reduction >20% from the preoperative baseline, and SBP <100mmHg. The duration of this event was also recorded. Consequences of hypotension were assessed in the context of AKI, Myocardial infarction and or stroke. Mortality was defined as inpatient mortality within 30days of surgery. Furthermore, a survey of anaesthetists was also distributed concurrently to gain an understanding of intended intra-operative treatments threshold for blood pressure. This survey correlated with the secondary aims of the iHype research initiative.
Data was collected from 4750 patients and 3366 anaesthetists completed the survey in 196 centres across England, Scotland and Wales. Non-invasive and invasive blood pressure readings were recorded. Data was collected from electronic and paper anaesthetic records. The incidence of intra-operative hypotension was 61% with MAP < 65mmHg, 77.5% of patients had a Systolic Blood pressure <100mmHg. More concerning is that 90.5% had a MAP >20% reduction from their normal BP and 91.3% had a reduction of their Systolic BP >20% from their normal. Interestingly, it was noted that the lowest blood pressure recorded was invariably after 30minutes of anaesthesia. Vasopressor use was recorded and interestingly 90.7% of patients blood pressure was treated with bolus of vasopressors rather than continuous infusions. Metaraminol was the most common vasopressor followed by phenylephrine. 7.3% of patients (345patients) had an adverse outcome – be it renal injury, myocardial injury, stroke or death.
As for the survey distributed to anaesthetists it also showed some interesting results. 59.2% of responses was from Consultant Anaesthetists. Anaesthetists most frequently stated that they intended to treat a 20% decrease in SBP or MAP; the most frequent SBP and MAP percentage decreases triggering treatment were 40% reductions.
The main concluding finding from this study suggests that the majority of anaesthetists area applying an absolute target that is below the treatment threshold SBP <90mmHg, MAP<65mmHg. This exposure to hypotension results in end organ dysfunction.
There are several limitations to the study which are highlighted by the research team – they include the reliance on handwritten anaesthetic records whose reliability can be questioned. They comment only on vasopressor use as a treatment for intra-operative hypotension, they don’t account for IV fluid administration, patient position adjustment or dose of anaesthetic adjustment. Furthermore, the use of pre-induction blood pressure as a value for comparison of intra-operative blood pressure may not always be accurate. A single BP in time is not always representative of a patients normal blood pressure. A patients preoperative frailty was not accounted for in terms of their postoperative co-morbidities and outcomes.
In conclusion, this study highlighted that intra-operative hypotension is common in patients >/=65years undergoing surgery in the UK. It also reinforces the need for national wide research. We need to commend the efforts of anaesthetic trainees and RAFT. It highlights our need as anaesthetists to increase our vigilance at targeting intra-operative blood pressure thresholds. It raises the question for the need for electronic records to enhance documentation of intra-operative blood pressure and more well designed clinical trials to define the best treatment strategies for intra-operative hypotension.
Journal Watch: January 2022
Evidence based strategies to reduce the incidence of post-operative delirium: a narrative review
C.J Swarbrick and J.S.L. Partridge. Anaesthesia 2022, 77 (Suppl. 1), 92–101. doi:10.1111/anae.15607
Edited by Siobhán Clarke
This review article focusses on delirium, one the most common postoperative complications affecting up to 40% of adult patients having surgery. Associated with increased postoperative mortality, morbidity, psychological sequelae and healthcare costs, delirium is preventable in up to 40% of cases.
At risk patients should be identified early in the pre-operative setting and while several delirium risk tools exist none of these have been validated in all elective and emergency surgical specialities. Most of the published evidence supports the use of non-pharmacological approaches in the prevention of delirium including multi-component intervention and comprehensive geriatric assessment. This narrative summary eloquently and concisely condenses this discussion.
Avoidance of certain medications e.g benzodiazepines is supported by strong evidence and multimodal analgesia including regional anaesthesia is recommended. There is conflicting evidence surrounding the use of steroids, dexamedetomidine and melatonin for the prevention of postoperative delirium. Burgeoning research suggests a correlation between depth of anaesthesia and post- operative delirium (1).
The age-old question of regional anaesthesia vs general anaesthesia rages on with a recent study in hip fracture patients concluding that mode of anaesthesia did not influence the incidence of postoperative delirium or survival (2). Finally, this narrative review addresses the challenges involved in multi-component interventions such as those needed in delirium prevention.