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Wiley Online Library : Anaesthesia
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Cerebral oximetry and postoperative delirium after cardiac surgery: a randomised, controlled trial

22. September 2017 - 7:10
Summary

Postoperative delirium is associated with increased morbidity and mortality. We hypothesised that restoration of regional cerebral oxygen desaturation would reduce the incidence of postoperative delirium in elderly patients after cardiac surgery. After institutional ethics review board approval and informed consent, a double-blinded, prospective, randomised, controlled trial was conducted in patients ≥ 60 years of age undergoing cardiac surgery with cardiopulmonary bypass. In the intervention group, an algorithm was commenced if regional cerebral oxygen saturation decreased below 75% of baseline value for 1 min or longer. In the control group, the cerebral oximetry monitor screen was electronically blinded. Assessment of delirium was performed with confusion assessment method for intensive care unit or confusion assessment method after discharge from intensive care unit at 12-h intervals for seven postoperative days. Postoperative delirium was present in 30 out of 123 (24.4%) and 31 out of 126 (24.6%) patients in the intervention and control groups, respectively, odds ratio 0.98 (95%CI 0.55–1.76), p = 0.97. Postoperative delirium was present in 20 (71%) out of 28 and in 41 (18%) out of 221 patients with baseline regional cerebral oxygen saturation ≤ 50, or > 50%, respectively, p = 0.0001. Higher baseline regional cerebral oxygen saturation and body mass index were protective against postoperative delirium. Restoration of regional cerebral oxygen desaturation did not result in lower postoperative delirium after cardiac surgery. Pre-operative regional cerebral oxygen saturation ≤ 50% was associated with increased postoperative delirium rates in elderly patients following cardiac surgery.

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Time for training?

18. September 2017 - 11:00
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Nasotracheal intubation over a bougie vs. non-bougie intubation: a prospective randomised, controlled trial in older children and adults using videolaryngoscopy

16. September 2017 - 4:16
Summary

Conventionally, nasotracheal intubation has consisted of blind nasal passage and external manipulation of the tube through the glottis (‘conventional technique’), a technique associated with a high incidence of nasal trauma. We evaluated a novel technique for routine asleep (i.e. post-induction) nasotracheal intubation using a bougie (‘bougie technique’), which uses a nasopharyngeal airway to guide a paediatric bougie nasotracheally for use as a Seldinger tracheal intubation guide. Two hundred and fifty-seven older children (> 8 years) and adults were randomly assigned to videolaryngoscopy-assisted nasotracheal intubation using either the conventional or the bougie technique. The hypothesis was that the bougie technique would result in less nasopharyngeal trauma. The bougie technique was associated with significantly less nasopharyngeal bleeding than the conventional technique at both 60–90 s (55% vs. 68%; p = 0.033) and 5 min (51% vs. 70%; p = 0.002). The severity of bleeding was also significantly less with the bougie technique, with an OR for active bleeding of 0.42 (95%CI 0.20–0.87; p = 0.020) at 60–90 s and 0.15 (95%CI 0.06–0.37; p < 0.0001) at 5 min. Magill forceps were needed significantly less often with the bougie technique (9% vs. 28%, p = 0.0001) and there was no difference in first attempt and overall success rates between the two techniques (p = 0.133 and p = 0.750, respectively). Not only is nasal intubation over a bougie as successful as the conventional technique, it also significantly decreases both the incidence and severity of nasopharyngeal trauma, as well as the need for the use of Magill forceps.

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Analgesic efficacy of local infiltration analgesia vs. femoral nerve block after anterior cruciate ligament reconstruction: a systematic review and meta-analysis

15. September 2017 - 5:00
Summary

Many published reports consider blockade of the femoral nerve distribution the best available analgesic treatment after anterior cruciate ligament reconstruction. However, some argue that an alternative approach of infiltrating local anaesthetic into the surgical site has similar efficacy. The objectives of this meta-analysis were to compare the analgesic and functional outcomes of both treatments following anterior ligament reconstruction. The primary outcomes were pain scores at rest (analogue scale, 0–10) in the early (0–2 postoperative hours), intermediate (3–12 hours) and late postoperative periods (13–24 hours). Secondary outcomes included range of motion, quadriceps muscle strength and complication rates (neurological problems, cardiovascular events, falls and knee infections). Eleven trials, including 628 patients, were identified. Pain scores in the early, intermediate and late postoperative periods were significantly lower in patients who received a femoral nerve block, with mean differences (95%CI) of 1.6 (0.2–2.9), p = 0.02; 1.2 (0.4–1.5), p = 0.002; and 0.7 (0.1–1.4), p = 0.03 respectively. The quality of evidence for our primary outcomes was moderate to high. Regarding functional outcomes, only one trial reported a similar range of motion between groups at 48 postoperative hours. No trial sought to record complications. In conclusion, femoral nerve block provides superior postoperative analgesia after anterior cruciate ligament reconstruction to local infiltration analgesia. The impact of improved analgesia on function remains unclear due to the lack of reporting of functional outcomes in the existing literature.

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The effect of neuromuscular blockade on the efficiency of facemask ventilation in patients difficult to facemask ventilate: a prospective trial

15. September 2017 - 4:51
Summary

Facemask ventilation of the lungs can be an important rescue intervention in a ‘cannot intubate’ scenario. We assessed the effect of neuromuscular blockade on expiratory tidal volumes in patients with expected difficulty in mask ventilation. The lungs of patients with at least three predictors of difficulty in mask ventilation were ventilated using a facemask held with two hands, with mechanical ventilation set in a pressure-controlled mode. Tidal volumes were recorded before and after the establishment of complete neuromuscular block. In 113 patients, median (IQR [range]) tidal volume increased from 350 (260–492 [80–850]) ml initially, by 48% to 517 (373–667 [100–1250]) ml 30 s after rocuronium administration, (p < 0.001). After the onset of the complete neuromuscular block, a median tidal volume of 600 (433–750 [250–1303]) ml was observed, corresponding to an increase of 71% from baseline values (p < 0.001), and 16% from values obtained 30 s after rocuronium administration, respectively; p = 0.003). No decrease in the tidal volume during the measurements was observed. We conclude that the administration of rocuronium at a dose of 0.6 mg.kg−1 was able to improve facemask ventilation in all cases with a potentially clinically relevant increase in tidal volume. The early use of a neuromuscular blocking agent can be considered as a therapeutic option in case of difficulty with mask ventilation.

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Real-time continuous monitoring of injection pressure at the needle tip for peripheral nerve blocks: description of a new method

15. September 2017 - 4:46
Summary

The measurement of injection pressure during the performance of peripheral nerve blocks can be pivotal to detect intraneural placement of the needle tip and thus avoid intrafascicular injection. However, injection pressure can only be measured along the injection line (tubing), which is influenced by several factors. The primary aim of this feasibility study was to describe and validate the principle of a novel nerve-block needle conceived for real-time continuous monitoring of injection pressures at the needle tip. Our secondary aim was to provide measurements and compare injection pressure values at the needle tip and in the injection line. Four porcine lower limb anatomic models were prepared and extraneural injections were performed with fractioned boluses of 2 ml saline at a controlled infusion rate of 10 ml.min−1 (0.16 ml.s−1). Injection pressure at the needle tip was monitored and compared with the pressure in the injection line. The system proved to be reliable. Thirty injections were successfully performed without technical failures. The mean (95%CI) difference between pressures at the needle tip and the injection line varied substantially from 14.33 (12.58–16.08) kPa at 0.5 ml injected volume to 41.56 (39.66–43.45) kPa at the end of the injection. This study demonstrates that the described system allows for real-time continuous monitoring of injection pressure at the needle tip. Moreover, this study shows that injection pressure values measured in the injection line cannot be assumed to be a reliable indicator of the injection pressure at the needle tip.

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Effects of epidural volume extension by saline injection on the efficacy and safety of intrathecal local anaesthetics: systematic review with meta-analysis, meta-regression and trial sequential analysis

11. September 2017 - 7:00
Summary

Epidural volume extension, a modification of combined spinal–epidural anaesthesia, involves the epidural injection of saline in order to increase the spread of drugs given intrathecally. Results from individual studies have so far been contradictory and we aimed to gather the available evidence for this technique. We performed a systematic literature search for randomised, controlled trials comparing epidural volume extension after spinal injection with a control group without epidural injection in patients undergoing surgery. Conventional meta-analyses, trial sequential analyses and meta-regression were performed, with the Grading of Recommendations on Assessment, Development and Evaluation (GRADE) approach used to express reliability of outcome estimates. We included 15 studies with 1177 participants. Meta-analyses for the primary outcomes, such as maximum sensory height (6 studies, 274 participants, mean difference (MD) (95%CI) −0.59 (−1.24 to 0.07) dermatomes, low-quality evidence) and hypotension (10 studies, 683 participants, risk ratio (95%CI) 0.84 (0.66–1.07), low-quality evidence), did not differ significantly between the two treatment arms, but trial sequential analysis suggested insufficient evidence to be certain of these findings. Meta-regression suggested a volume-dependent effect, with higher volumes causing a higher spread of intrathecal drugs and a higher incidence of hypotension. A sub-group analysis indicated a pronounced effect on motor block recovery time when a lower anaesthetic dose plus epidural volume extension was compared with a higher anaesthetic dose without epidural volume extension, the MD (95%CI) being −66.75 (−76.0 to −57.5) min, with trial sequential analysis suggesting the evidence was sufficient to draw this conclusion. In trials using the same anaesthetic mixture in the epidural volume extension and the control groups, motor block recovery time did not differ between groups, with a MD (95%CI) of −1.06 (−5.48 to 3.36) min, although trial sequential analysis suggested insufficient evidence. In summary, there is not enough evidence to draw definite conclusions on the effect of epidural volume extension. The quality of the current evidence is low for both efficacy (maximum sensory height) and safety (hypotension). However, there may be a significantly shorter motor block recovery time when different anaesthetic mixtures are used in epidural volume extension and control groups; this warrants further investigation.

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The association of postoperative pulmonary complications in 109,360 patients with pressure-controlled or volume-controlled ventilation

11. September 2017 - 6:55
Summary

We thought that the rate of postoperative pulmonary complications might be higher after pressure-controlled ventilation than after volume-controlled ventilation. We analysed peri-operative data recorded for 109,360 adults, whose lungs were mechanically ventilated during surgery at three hospitals in Massachusetts, USA. We used multivariable regression and propensity score matching. Postoperative pulmonary complications were more common after pressure-controlled ventilation, odds ratio (95%CI) 1.29 (1.21–1.37), p < 0.001. Tidal volumes and driving pressures were more varied with pressure-controlled ventilation compared with volume-controlled ventilation: mean (SD) variance from the median 1.61 (1.36) ml.kg−1 vs. 1.23 (1.11) ml.kg−1, p < 0.001; and 3.91 (3.47) cmH2O vs. 3.40 (2.69) cmH2O, p < 0.001. The odds ratio (95%CI) of pulmonary complications after pressure-controlled ventilation compared with volume-controlled ventilation at positive end-expiratory pressures < 5 cmH2O was 1.40 (1.26–1.55) and 1.20 (1.11–1.31) when ≥ 5 cmH2O, both p < 0.001, a relative risk ratio of 1.17 (1.03–1.33), p = 0.023. The odds ratio (95%CI) of pulmonary complications after pressure-controlled ventilation compared with volume-controlled ventilation at driving pressures of < 19 cmH2O was 1.37 (1.27–1.48), p < 0.001, and 1.16 (1.04–1.30) when ≥ 19 cmH2O, p = 0.011, a relative risk ratio of 1.18 (1.07–1.30), p = 0.016. Our data support volume-controlled ventilation during surgery, particularly for patients more likely to suffer postoperative pulmonary complications.

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S-shaped tracheal tubes for videolaryngoscopy

11. September 2017 - 5:42
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Issue Information – Editorial Board

11. September 2017 - 5:42
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Medtronic electromyographic tracheal tube

11. September 2017 - 5:42
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A survey of acute pain services in the UK

11. September 2017 - 5:42
Summary

The organisational state of inpatient pain management in UK hospitals is difficult to determine. We sent an electronic questionnaire to 209 acute pain service leads throughout the UK. Questions were about staffing and service provision. We received 141 responses (67%); 47% of all UK hospitals. Each service was responsible for a median (IQR [range]) of 566 (400–839 [120–2800]) beds. Each acute pain specialist nurse was responsible for 299 (238–534 [70–1923]) beds. The mean (SD) number of consultant hours per week was 5.54 (4.62), delivered by a median of 1.0 (1.0–2.5 [0.2–7.0]) consultant. Overnight cover was provided by 20 (15%) acute pain services, and weekend cover by 39 (29%). Acute pain services commonly (in 50 (35%) hospitals) had roles in addition to acute pain management. Most teams (105, (77%)) reviewed medical patients and patients with chronic pain (in 131, (96%) teams). Half of the services (56, (49%)), reported that they were part of an integrated acute and chronic pain service, however, 83 (59%) did not have any members who work in chronic pain clinics. The majority (79, (70%)) were able to access a nominated chronic pain consultant for advice. Provision of acute pain services throughout the UK is highly variable. The majority do not meet core UK standards.

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