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The effect of pre-operative methylprednisolone on early endothelial damage after total knee arthroplasty: a randomised, double-blind, placebo-controlled trial

From Anaesthesia - 26. July 2017 - 6:40
Summary

We wished to evaluate whether inhibition of the systemic inflammatory response by a single pre-operative dose of methylprednisolone reduced markers of early endothelial damage after fast-track total knee arthroplasty. We randomly allocated 70 patients undergoing elective unilateral total knee arthroplasty (1:1) to receive either pre-operative intravenous methylprednisolone 125 mg (methylprednisolone group) or isotonic saline (control group). All procedures were performed under spinal anaesthesia without a tourniquet, using a standardised multimodal analgesic regime. The outcomes included changes in Syndecan-1 concentrations, a marker of glycocalyx degradation, markers of endothelial cell damage and activation (plasma soluble thrombomodulin and sE-Selectin), and permeability by vascular endothelial growth factor, as well as C-reactive protein concentrations. Blood samples were collected at baseline and 2 h, 6 h and 24 h after surgery, with complete sampling from 63 patients for analyses. Methylprednisolone significantly reduced markers of endothelial damage at 24 h following surgery compared with saline (methylprednisolone group vs. control group, adjusted means (SEM)) expressed by circulating Syndecan-1: 11.6 (1.0) ng.ml−1 vs. 13.4 (1.1) ng.ml−1 p = 0.046; soluble thrombomodulin: 5.1 (0.1) ng.ml−1 vs. 5.7 (0.2) ng.ml−1, p = 0.009; sE-Selectin: 64.8 (1.8) ng.ml−1 vs. 75.7 (1.9) ng.ml−1, p = 0.001, and vascular endothelial growth factor: 35.3 (2.7) ng.ml−1 vs. 58.5 (2.8) ng.ml−1, p < 0.001. The effect of the intervention increased with time for soluble thrombomodulin, sE-Selectin and vascular endothelial growth factor, and was more pronounced in patients with high baseline values. Finally, methylprednisolone reduced the C-reactive protein response 24 h postoperatively; 31.1 (1.1) mg.l−1 vs. 68.4 (1.1) mg.l−1, p < 0.001. Pre-operative administration of methylprednisolone 125 mg reduced circulating markers of endothelial activation and damage, as well as the systemic inflammatory response (C-reactive protein) early after fast-track total knee arthroplasty. These findings may have a positive effect on surgical outcome, but require studies in major surgery.

Categories: From Anaesthesia

A randomised controlled trial of oral chloral hydrate vs. intranasal dexmedetomidine before computerised tomography in children

From Anaesthesia - 25. July 2017 - 12:10
Summary

Chloral hydrate is commonly used to sedate children for painless procedures. Children may recover more quickly after sedation with dexmedetomidine, which has a shorter half-life. We randomly allocated 196 children to chloral hydrate syrup 50 mg.kg−1 and intranasal saline spray, or placebo syrup and intranasal dexmedetomidine spray 3 μg.kg−1, 30 min before computerised tomography studies. More children resisted or cried after drinking chloral hydrate syrup than placebo syrup, 72 of 107 (67%) vs. 42 of 87 (48%), p = 0.009, but there was no difference after intranasal saline vs. dexmedetomidine, 49 of 107 (46%) vs. 40 of 87 (46%), p = 0.98. Sedation was satisfactory in 81 of 107 (76%) children after chloral hydrate and 64 of 87 (74%) children after dexmedetomidine, p = 0.74. Of the 173 children followed up for at least 4 h after discharge, 38 of 97 (39%) had recovered normal function after chloral hydrate and 32 of 76 (42%) after dexmedetomidine, p = 0.76. Six children vomited after chloral hydrate syrup and placebo spray vs. none after placebo syrup and dexmedetomidine spray, p = 0.03.

Categories: From Anaesthesia

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

From Anaesthesia - 25. July 2017 - 11:43
Summary

This study aimed to investigate the validity of the oxygen uptake efficiency slope as an objective and submaximal indicator of cardiorespiratory fitness in elderly patients scheduled for major colorectal surgery. Patients ≥ 60 years of age, with a metabolic equivalent score using the Veterans Activity Questionnaire ≤ 7 and scheduled for major colorectal surgery participated in a pre-operative cardiopulmonary exercise test. The oxygen uptake efficiency slope was calculated up to different exercise intensities, using 100%, 90% and 80% of the exercise data. Data from 71 patients (47 men, mean (SD) age 75.2 (6.7) years) were analysed. The efficiency slope obtained from all the data was statistically significantly different from the values when 90% (p = 0.027) and 80% (p = 0.023) of the data were used. The 90% and 80% values did not differ significantly from each other (p = 0.152). Correlations between the oxygen uptake efficiency slope and the peak oxygen uptake ranged from 0.816 to 0.825 (all p < 0.001), and correlations between oxygen uptake efficiency slope and the ventilatory anaerobic threshold ranged from 0.793 to 0.805 (all p < 0.001). Receiver operating characteristic curves showed that the oxygen uptake efficiency slope is a sensitive and specific predictor of a peak oxygen uptake ≤ 18.2 ml.kg−1.min−1, with an area under the curve (95%CI) of 0.876 (0.780–0.972, p < 0.001) and a ventilatory anaerobic threshold ≤ 11.1 ml.kg−1.min−1, with an area under the curve (95%CI) of 0.828 (0.726–0.929, p < 0.001). These correlations suggest that the oxygen uptake efficiency slope provides a valid (sub)maximal measure of cardiorespiratory fitness in these patients, and the predictive ability described indicates that it might help discriminate patients at higher risk of postoperative morbidity. However, future research should investigate the prognostic value of the oxygen uptake efficiency slope for postoperative outcomes.

Categories: From Anaesthesia

A randomised, controlled trial of rectus sheath bupivacaine and intrathecal bupivacaine, without or with intrathecal morphine, vs. intrathecal bupivacaine and morphine after caesarean section

From Anaesthesia - 25. July 2017 - 11:15
Summary

We recruited 144 women of whom 131 underwent scheduled caesarean section and were allocated to intrathecal bupivacaine without (46) or with (47) morphine and postoperative rectus sheath bupivacaine; or intrathecal bupivacaine with morphine and postoperative rectus sheath saline (38). We measured postoperative pain with a 10-point numeric rating scale. The mean (SD) areas under the curve for pain on movement during 48 postoperative hours were 273.5 (63.6), 223.8 (80.7) and 223.8 (80.7), respectively, p = 0.008. There was no difference between women who had intrathecal morphine with or without rectus sheath bupivacaine, p = 1. The equivalent values for pain at rest were 160.8 (64.7), 85.8 (79.4) and 82.8 (74.3), respectively, p < 0.001. There was no difference between women who had intrathecal morphine with or without rectus sheath bupivacaine, p = 0.98.

Categories: From Anaesthesia

The effect of metrics-based feedback on acquisition of sonographic skills relevant to performance of ultrasound-guided axillary brachial plexus block

From Anaesthesia - 25. July 2017 - 10:35
Summary

The objective of this study was to examine the effect of metrics-based vs. non-metrics-based feedback on novices learning predefined competencies for acquisition and interpretation of sonographic images relevant to performance of ultrasound-guided axillary brachial plexus block. Twelve anaesthetic trainees were randomly assigned to either metrics-based-feedback or non-metrics-based feedback groups. After a common learning phase, all participants attempted to perform a predefined task that involved scanning the left axilla of a single volunteer. Following completion of the task, all participants in each group received feedback from a different expert in regional blocks (consultant anaesthetist) and were allowed to practise the predefined task for up to 1 h. Those in the metrics-based feedback group received feedback based on previously validated metrics, and they practised each metric item until it was performed satisfactorily, as assessed by the supervising consultant. Subsequently, each participant attempted to perform ultrasonography of the left axilla on the same volunteer. Two trained consultant anaesthetists independently scored the video recording pre- and post-feedback scans using the validated metrics list. Both groups showed improvement from pre-feedback to post-feedback scores. Compared with participants in the non-metrics-based feedback group, those in the metrics-based feedback group completed more steps: median (IQR [range]) 18.8 (1.5 [17–20]) vs. 14.3 (4.5 [11–18.5]), p = 0.009, and made fewer errors 0.5 (1 [0–1.5]) vs. 1.5 (2 [1–6]), p = 0.041 postfeedback. In this study, novices’ sonographic skills showed greater improvement when feedback was combined with validated metrics.

Categories: From Anaesthesia

The association of abdominal muscle with outcomes after scheduled abdominal aortic aneurysm repair

From Anaesthesia - 25. July 2017 - 10:15
Summary

Sarcopenia is the degenerative loss of core muscle mass. It is an aspect of frailty, which is associated with increased rates of peri-operative harm. We assessed the association of the cross-sectional areas of abdominal muscles, including psoas, with survival during a median (IQR [range]) follow-up of 3.8 (3.2–4.4 [0.0–5.1]) years after scheduled endovascular (132) or open (5) abdominal aortic aneurysm repair in 137 patients. In multivariate analysis, mortality hazard (95%CI) was independently associated with: age, 1.06 (1.01–1.13) per year, p = 0.03; and the adjusted area of the left psoas muscle, 0.94 (0.81–1.01) per mm2.kg−0.83, p = 0.08. Shortened hospital stay was independently associated with haemoglobin concentration and adjusted left psoas muscle area, hazard ratio (95%) 1.01 (1.00–1.02) per g.l−1 and 1.05 (1.02–1.07) per mm2.kg−0.83, p = 0.04 and 0.001, respectively.

Categories: From Anaesthesia

A network meta-analysis of the clinical properties of various types of supraglottic airway device in children

From Anaesthesia - 24. July 2017 - 12:12
Summary

We conducted both conventional pairwise and Bayesian network meta-analyses to compare the clinical properties of supraglottic airway devices in children. We searched six databases for randomised clinical trials. Our primary end-points were oropharyngeal leak pressure, risk of insertion failure at first attempt, and blood staining risk. The risk of device failure, defined as the abandonment of the supraglottic airway device and replacement with a tracheal tube or another device, was also analysed. Sixty-five randomised clinical trials with 5823 participants were identified, involving 16 types of supraglottic airway device. Network meta-analysis showed that the i-gel™, Cobra perilaryngeal airway™ and Proseal laryngeal mask airway (LMA®-Proseal) showed statistically significant differences in oropharyngeal leak pressure compared with the LMA®-Classic, with mean differences (95% credible interval, CrI) of 3.6 (1.9–5.8), 4.6 (1.7–7.6) and 3.4 (2.0–4.8) cmH2O, respectively. The i-gel was the only device that significantly reduced the risk of blood staining of the device compared with the LMA-Classic, with an odds ratio (95%CrI) of 0.46 (0.22–0.90). The risk (95%CI) of device failure with the LMA-Classic, LMA®-Unique and LMA-Proseal was 0.36% (0.14–0.92%), 0.49% (0.13–1.8%) and 0.50% (0.23–1.1%), respectively, whereas the risk (95%CI) of the i-gel and PRO-Breathe was higher, at 3.4% (2.5–4.7%) and 6.0% (2.8–12.5%), respectively. The risk, expressed as odds ratio (95%CrI), of insertion failure at first attempt, was higher in patients weighing < 10 kg at 5.1 (1.6–20.1). We conclude that the LMA-Proseal may be the best supraglottic airway device for children as it has a high oropharyngeal leak pressure and a low risk of insertion. Although the i-gel has a high oropharyngeal leak pressure and low risk of blood staining of the device, the risk of device failure should be evaluated before its routine use can be recommended.

Categories: From Anaesthesia

The association between peri-operative acute risk change (ARC) and long-term survival after cardiac surgery

From Anaesthesia - 13. July 2017 - 6:10
Summary

Acute risk change has been described as the difference in calculated mortality risk between the pre-operative and postoperative periods of cardiac surgery. We aimed to assess whether this was associated with long-term survival after cardiac surgery. We retrospectively analysed 22,570 cardiac surgical patients, with minimum and maximum follow-up of 1.0 and 6.7 years. Acute risk change was calculated as the arithmetic difference between pre- and postoperative mortality risk. ‘Rising risk’ represented an increase in risk from pre- to postoperative phase. The primary outcome was one-year mortality. Secondary outcomes included mortality at 3 and 5 years and time to death. Univariable and multivariable analyses were undertaken to examine the relationship between acute risk change and outcomes. Rising risk was associated with higher mortality (5.6% vs. 3.5%, p < 0.001). After adjusting for baseline risk, rising risk was independently associated with increased 1-year mortality (OR 2.6, 95%CI 2.2–3.0, p < 0.001). The association of rising risk with long-term survival was greatest in patients with highest baseline risk. Cox regression confirmed rising risk was associated with shorter time to death (HR 1.86, 1.68–2.05, p < 0.001). Acute risk change may represent peri-operative clinical events in combination with unmeasured patient risk and noise. Measuring risk change could potentially identify patterns of events that may be amenable to investigation and intervention. Further work with case review, and risk scoring with shared variables, may identify mechanisms, including the interaction between miscalibration of risk and true differences in peri-operative care.

Categories: From Anaesthesia

Arterial to end-tidal carbon dioxide difference in children undergoing mechanical ventilation of the lungs during general anaesthesia

From Anaesthesia - 11. July 2017 - 12:21
Summary

Capnography (ETCO2) is routinely used as a non-invasive estimate of arterial carbon dioxide (PaCO2) levels in order to modify ventilatory settings, whereby it is assumed that there is a positive gap between PaCO2 and ETCO2 of approximately 0.5 kPa. However, negative values (ETCO2 > PaCO2) can be observed. We retrospectively analysed arterial to end-tidal carbon dioxide differences in 799 children undergoing general anaesthesia with mechanical ventilation of the lungs in order to elucidate predictors for a negative gap. A total of 2452 blood gas analysis readings with complete vital sign monitoring, anaesthesia gas analysis and spirometry data were analysed. Mean arterial to end-tidal carbon dioxide difference was −0.18 kPa (limits of 95% agreement −1.10 to 0.74) and 71.2% of samples demonstrated negative values. The intercept model revealed PaCO2 to be the strongest predictor for a negative PaCO2-ETCO2 difference. A decrease in PaCO2 by 1 kPa resulted in a decrease in the PaCO2-ETCO2 difference by 0.23 kPa. This study demonstrates that ETCO2 monitoring in children whose lungs are mechanically ventilated may paradoxically lead to overestimation of ETCO2 (ETCO2 > PaCO2) with a subsequent risk of unrecognised hypocarbia.

Categories: From Anaesthesia

Ultrasonographic gastric volume before unplanned surgery

From Anaesthesia - 11. July 2017 - 12:21
Summary

We aimed to measure gastric antral cross-sectional area with ultrasound and estimate the gastric volume of 300 patients before unplanned surgery, fasted for at least six hours. Measurements were successfully recorded in 263 semi-recumbent patients. The median (IQR [range]) area was 333 (241–472 [28–1803]) mm2 and the mean (SD) estimated volume was 45.8 (34.0) ml. The area exceeded 410 mm2 in 92/263 (35%) measurements. Body mass index and morphine administration were associated with larger gastric areas on multivariable linear regression analysis, with beta coefficient (95%CI) 0.02 (0.01–0.04), p = 0.01, 0.23 (0.01–0.46), p = 0.04, respectively. Fasting time was not associated with gastric area and therefore could not substitute for ultrasound measurements in this cohort.

Categories: From Anaesthesia

Strength of commonly used spinal needles: the ability to deform and resist deformation

From Anaesthesia - 11. July 2017 - 12:21
Summary

We investigated the strength of commonly used spinal needles in relation to the amount of deformation, and registered forces during standardised testing. We investigated differences between manufacturers for the same length and gauge of Luer and non-Luer needles, and examined the effect of the internal stylet in terms of needle strength. A specialised rig was designed to perform the testing in both the horizontal and axial plane, reflecting common industrial tests and clinical use. Needles from four commonly used manufacturers were used (Vygon, Becton Dickinson, B Braun, and Pajunk). Needles of 25 G and 27 G were tested in 90-mm and 120-mm lengths. We found significant differences in terms of the size of final deformation and ‘toughness’/resistance to deformation between needles of different brands. There were also significant differences between horizontal tests conducted as an industry standard and our own axial test. This may have bearing on clinical use in terms of the incidence of bending and breakage. The presence of the internal stylet resulted in significantly greater toughness in many needles, but had little effect on the degree of deformation. Comparison of Luer and non-Luer needles of the same brand and size showed few significant differences in strength. This result is reassuring, given the imminent change from Luer to non-Luer needles that is to occur in the UK.

Categories: From Anaesthesia

Patient-controlled analgesia with remifentanil vs. alternative parenteral methods for pain management in labour: a Cochrane systematic review

From Anaesthesia - 11. July 2017 - 8:47
Summary

We aimed to assess the effectiveness of remifentanil used as intravenous patient-controlled analgesia for the pain of labour. We performed a systematic literature search in December 2015 (updated in December 2016). We included randomised, controlled and cluster-randomised trials of women in labour with planned vaginal delivery receiving patient-controlled remifentanil compared principally with other parenteral and patient-controlled opioids, epidural analgesia and continuous remifentanil infusion or placebo. The primary outcomes were patient satisfaction with pain relief and the occurrence of adverse events for mothers and newborns. We assessed risk of bias for each included study and applied the GRADE approach for the quality of evidence. We included total zero event trials, using a constant continuity correction of 0.01 and a random-effect meta-analysis. Twenty studies were included in the qualitative analysis; within these, 3713 participants were randomised and 3569 analysed. Most of our pre-specified outcomes were not studied in the included trials. However, we found evidence that women using patient-controlled remifentanil were more satisfied with pain relief than women receiving parenteral opioids (four trials, 216 patients, very low quality evidence) with a standardised mean difference ([SMD] 95%CI) of 2.11 (0.72–3.49), but were less satisfied than women receiving epidural analgesia (seven trials, 2135 patients, very low quality evidence), −0.22 (−0.40 to −0.04). Data on adverse events were sparse. However, the relative risk (95%CI) for maternal respiratory depression for patient-controlled remifentanil compared with epidural analgesia (three trials, 687 patients, low-quality evidence) was 0.91 (0.51–1.62). Compared with continuous intravenous infusion of remifentanil (two trials, 135 patients, low-quality evidence) no conclusion could be reached as all study arms showed zero events. The relative risk (95%CI) of Apgar scores less than 7 at 5 min after birth compared with epidural analgesia (five trials, 1322 participants, low-quality evidence) was 1.26 (0.62–2.57).

Categories: From Anaesthesia

THRIVE and airway fires

From Anaesthesia - 11. July 2017 - 8:47
Categories: From Anaesthesia