The effect of magnesium sulphate infusion on the incidence and severity of emergence agitation in children undergoing adenotonsillectomy using sevoflurane anaesthesia

This randomised, controlled, double‐blind study investigated the effects of intra‐operative magnesium sulphate administration on the incidence of emergence agitation in children undergoing adenotonsillectomy using sevoflurane anaesthesia. Seventy children were randomly allocated to receive a 30 mg.kg^?1 bolus of intravenous magnesium sulphate after induction of anaesthesia followed by a continuous infusion of 10 mg.kg^?1.h^?1 or an equal volume of saline 0.9%. All children received titrated sevoflurane anaesthesia adjusted to maintain haemodynamic stability. The Pediatric Anesthesia Emergence Delirium scale and the Children's Hospital of Eastern Ontario Score were used for the assessment of postoperative emergence agitation and pain, respectively. Emergence agitation was more common in the control group than in the magnesium group (23 (72%) and 12 (36%), respectively (p = 0.004)), with a relative risk of 0.51 (95% CI 0.31–0.84), an absolute risk reduction of 0.35 (95% CI 0.10–0.54), and number needed to treat of 3 (95% CI 2–9). Postoperative pain scores were comparable in the two groups. Magnesium sulphate reduces the incidence and severity of emergence agitation in children undergoing adenotonsillectomy using sevoflurane anaesthesia and is not associated with increased postoperative side‐effects or delayed recovery.     

Effect of magnesium sulphate on sugammadex reversal time for neuromuscular blockade: a randomised controlled study

Magnesium potentiates neuromuscular blockade. Sugammadex reverses rocuronium‐induced blockade. The aim of this study was to determine the effect of pre‐treatment with magnesium sulphate on sugammadex reversal time for neuromuscular blockade. Seventy‐three patients were randomly assigned to receive magnesium sulphate (40 mg.kg^?1) or saline intravenously. After anaesthetic induction, continuous train‐of‐four monitoring was performed and rocuronium was administered (0.6 mg.kg^?1). When a second twitch appeared, the patients received sugammadex (2 mg.kg^?1). The median (IQR [range]) reversal time of moderate neuromuscular blockade to a train‐of‐four ratio of 0.9 facilitated by sugammadex was 115 (93?177.5 [68?315]) s in the magnesium group and 120 (105?140 [70?298]) s in the saline group (p = 0.79). The median (IQR [range]) clinical duration was 45 (35.5?53 [22?102]) min in the magnesium group and 37 (31?43 [19?73]) min in the saline group (p = 0.031). Pre‐treatment with magnesium did not significantly affect sugammadex reversal time of moderate neuromuscular blockade induced by rocuronium.     

The immunomodulatory role of esmolol in patients undergoing laparoscopic gastrectomy due to gastric cancer

Esmolol has a beneficial effect on the T helper 1/T helper 2 balance in patients with heart failure. The aim of this study was to investigate the immunomodulatory role of esmolol during and after surgery. Patients undergoing laparoscopic gastrectomy due to gastric cancer were enrolled. Patients in the esmolol group (n = 15) received esmolol during surgery, and a saline‐treated group (n = 14) served as a control. Cytokines were quantified by sandwich enzyme‐linked immunoassays before, during and after surgery. The esmolol group was associated with higher ratios of interferon‐γ/interleukin‐4 (T helper 1/T helper 2 signature cytokines) than the saline group during (2.36 vs 0.57, respectively, p = 0.041) and after (5.79 vs 0.69, respectively, p = 0.033) surgery. The postoperative increase in interleukin‐6 was attenuated in the esmolol group, and the C‐reactive protein level on postoperative day 1 was significantly lower in the esmolol group than in the saline group (mean (SD) 26.2 (18.3) mmol.l^?1 vs 56.8 (44.3) mmol.l^?1, p = 0.021). Our findings suggest that esmolol played an immunomodulatory role and mitigated the postoperative inflammatory response in patients under surgical and anaesthetic stress.     

The effects of intra‐operative dexmedetomidine on postoperative pain,side‐effects and recovery in colorectal surgery

In this double‐blind, randomised study, 100 patients undergoing open or conventional laparoscopic colorectal surgery received an intra‐operative loading dose of dexmedetomidine 1 μg.kg^?1 followed by an infusion of 0.5 μg.kg^?1.h^?1, or a bolus and infusion of saline 0.9% of equivalent volume. Forty‐six patients in the dexmedetomidine group and 50 in the saline group completed the study. The area under the curve of numerical rating scores for pain at rest for 1–48 h postoperatively was significantly lower in the patients receiving dexmedetomidine (p = 0.041). There was no difference in morphine consumption, duration of recovery ward or hospital stay. From the data obtained in this study, we calculated a number needed to treat for effective pain relief of 4. Intra‐operative dexmedetomidine in colorectal surgery resulted in a reduction in resting pain scores, but there was no morphine‐sparing effect or improvement in patients' recovery outcome measures.     

Effects of magnesium sulphate on suxamethonium-induced complications during rapid-sequence induction of anaesthesia

Twenty patients were studied in a double-blind manner to investigate whether magnesium sulphate, when given during a rapid-sequence induction of anaesthesia, lessens the side effects caused by suxamethonium. Patients were randomly allocated to two groups; equal volumes of either magnesium sulphate (40 mg.kg^-1) or saline were given during rapid-sequence induction of anaesthesia, after thiopentone but before the administration of suxamethonium (1.5 mg.kg^-1). The changes in the serum potassium concentration, the degree of muscle fasciculations and the presence of postoperative myalgia were recorded. The mean serum potassium concentration increased by 0.08 mmol.l^-1 in the magnesium group and by 0.1 mmol.l^-1 in the control group at 2 min after injection of suxamethonium; in neither group was there a significant increase from baseline values. The systolic blood pressure and heart rate increased in both groups after tracheal intubation. The incidence of fasciculations was significantly lower in the magnesium group. Magnesium did not clinically prolong muscle relaxation. There was no difference between the groups in the incidence of myalgia after surgery (one patient in each group). Since no significant increase in the serum potassium concentration was demonstrated, no assessment could be made of the effect of magnesium sulphate on the serum potassium concentration after administration of suxamethonium.     

Conditioning out‐of‐date bank‐stored red blood cells using a cell‐saver auto‐transfusion device: effects on numbers of red cells and quality of suspension fluid

We investigated the utility of a cell‐saver device for processing out‐of‐date red blood cells, by washing twenty bags of red blood cells that had been stored for between 36 and 55 days. The volume of recovered cells, and the characteristics of the suspension fluid, were measured before and after treatment. The ratio of free haemoglobin to total haemoglobin was up to 0.02 before processing, and up to 0.011 afterwards, changing by between ?0.013 and +0.003. This ratio met the current standard for free haemoglobin (less than 0.008 in more than 75% of samples), both before and after processing. Ninety‐three percent of red blood cells survived the process. Potassium ion concentration fell from above 15 mmol.l^?1 in all cases, to a mean of 6.4 mmol.l^?1 (p < 0.001). The pH rose to a mean value of 6.44 (p = 0.001). Lactate ion concentration fell to a mean value of 14 mmol.l^?1 (p < 0.001). Sodium ion concentration rose from a mean value of 93 mmol.l^?1 to a mean value of 140 mmol.l^?1 (p < 0.001). A useful proportion of out‐of‐date red blood cells remained intact after conditioning using a cell‐saver, and the process lowered concentrations of potentially toxic solutes in the fluid in which they were suspended.     

A randomised study of intranasal dexmedetomidine and oral ketamine for premedication in children

We studied the effects of intranasal dexmedetomidine combined with oral ketamine for premedication in children. One hundred and sixty children aged between 2 and 6 years were randomly allocated to one of four groups: 1 μg.kg^?1 intranasal dexmedetomidine with 3 mg.kg^?1 oral ketamine (Group 1); 1 μg.kg^?1 intranasal dexmedetomidine with 5 mg.kg^?1 oral ketamine (Group 2); 2 μg.kg^?1 intranasal dexmedetomidine with 3 mg.kg^?1 oral ketamine (Group 3); and 2 μg.kg^?1 intranasal dexmedetomidine with 5 mg.kg^?1 oral ketamine (Group 4). Sedation levels 10, 20 and 30 min after premedication were evaluated using a 5‐point sedation scale. A 4‐point emotional state score was used to evaluate patients when they were separated from their parents and their response to intravenous cannulation or facemask application. Approximately 90% of patients readily accepted premedication and onset times of acceptable sedation were similar in all four groups. Patients in Group 4 were significantly more sedated than those in Group 1 after 30 min (p = 0.036). A significantly higher proportion of patients in Group 3 (84%) and Group 4 (87%) accepted intravenous cannulation compared with those in Group 1 (40%) and Group 2 (54%) (p = 0.001). We conclude that the administration of 2 μg.kg^?1 intranasal dexmedetomidine and 3 mg.kg^?1 oral ketamine was the optimal combination, with children being easily separated from their parent, accepting intravenous cannulation and without causing excessive side‐effects or postoperative complications.     

Haemoconcentration of residual cardiopulmonary bypass blood using Hemosep®: a randomised controlled trial

Cardiac surgery and cardiopulmonary bypass are associated with haemodilution, activation of haemostasis and blood transfusion. We undertook a randomised controlled trial that included 53 patients in order to compare autotransfusion of residual cardiopulmonary bypass blood with residual blood concentrated using the novel Hemosep^® device. There was no difference in patients' mean (SD) haemoglobin concentration after autotransfusion of unprocessed blood compared with Hemosep; 103.5 (10.2) g.l^?1 vs 106.2 (12.4) g.l^?1, respectively, p = 0.40. The mean (SD) change in haemoglobin concentration after autotransfusion was 5.9 (5.3) g.l^?1 in the control group compared with 4.9 (6.3) g.l^?1 in the Hemosep group, p = 0.545. Adjusted for baseline haemoglobin concentrations, the estimated mean (95% CI) difference in change in haemoglobin concentration (control vs Hemosep) was 0.57 (?2.65 to 3.79) g.l^?1, p = 0.72. This was despite Hemosep's reducing the weight of the blood from a mean (SD) of 778.7 (243.0) g to 607.3 (248.2) g, p < 0.001. The haemoglobin concentration in the processed blood increased from a mean (SD) of 87.0 (15.1) g.l^?1 to 103.7 (17.4) g.l^?1, p < 0.001. We conclude that Hemosep is capable of haemoconcentration when employed to process residual cardiopulmonary bypass blood, but that this is insufficient to increase patient haemoglobin.     

Remifentanil for labour analgesia: a double‐blinded,randomised controlled trial of maternal and neonatal effects of patient‐controlled analgesia versus continuous infusion

This trial aimed to compare the maternal and neonatal effects of remifentanil given by patient‐controlled analgesia (PCA) or continuous infusion for labour analgesia. Patient controlled analgesia was administered using increasing stepwise boluses from 0.1 to 0.4 μg.kg^?1 (0.1 μg.kg^?1 increment, 2 min lockout, n = 30). Continuous infusion used rates from 0.05 to 0.2 μg.kg^?1.min^?1 (0.05 μg.kg^?1.min^?1 increment, n = 30). Dose increments were given on request. Women reported lowest pain scores (median (IQR [range]) of 3 (2–4 [2–5]) for PCA and 4 (3–5.25 [3–7]) for continuous infusion (p = 0.004) at 60 min after the beginning of analgesia. The mean (SD) remifentanil umbilical vein/maternal artery ratio in the PCA and infusion groups were 0.74 (0.45) vs 0.70 (0.52), respectively (p = 0.776). The mean (SD) umbilical artery/umbilical vein ratios were 0.31 (0.12) vs 0.26 (0.07), respectively (p = 0.088). Maternal and neonatal adverse reactions of remifentanil were similar between the two groups. The total remifentanil consumption (median (IQR [range]) during PCA administration was lower than continuous infusion, 1.34 (1.22–1.48 [0.89–1.69]) mg vs 1.49 (1.35–1.61 [1.12–1.70] mg; p = 0.011). The results suggest that remifentanil PCA provides better pain relief and similar placental transfer compared with continuous infusion.     

Clinical and economic impact of a switch from high‐ to low‐volume renal replacement therapy in patients with acute kidney injury

High‐intensity renal replacement therapy protocols in intensive care patients with acute kidney injury have failed to translate to improved patient outcomes when compared with lower‐intensity protocols. This retrospective study explored the clinical and economic impacts of switching from a 30–35 ml.kg^?1.h^?1 (high‐volume) to a 20 ml.kg^?1.h^?1 (low‐volume) protocol. Patients (n = 366) admitted 12 months before (n = 187) and after (n = 179) the switch were included in the study. There was no difference in in‐hospital mortality (77/187 (41%) vs 75/179 (42%), respectively, p = 0.92), intensive care unit mortality (55/187 (29%) vs 61/179 (34%), respectively, p = 0.40), duration of organ support or extent of renal recovery between the high‐ and low‐volume cohorts. A 25% reduction in daily replacement fluid usage was observed, equating to a cost saving of over £27 000 per annum. In conclusion, a switch from high‐ to low‐volume continuous haemodiafiltration had minimal effects on clinical outcomes and resulted in marked cost savings.     

A randomised controlled trial comparing rocuronium priming, magnesium pre-treatment and a combination of the two methods

We investigated whether magnesium sulphate combined with rocuronium priming shortens the onset of neuromuscular blockade, compared with these methods used alone. Ninety‐two patients scheduled for general anaesthesia were randomly allocated to one of four groups: controls were given 0.6 mg.kg^?1 rocuronium; patients in the prime group were given 0.06 mg.kg^?1 rocuronium three minutes before a further dose of 0.54 mg.kg^?1 rocuronium; patients in the magnesium group were given an infusion of 50 mg.kg^?1 magnesium sulphate before rocuronium and patients in the magnesium and prime group were given both the magnesium sulphate and the priming dose of rocuronium. Tracheal intubation was attempted 40 s after the rocuronium injection. The time to onset of neuromuscular blockade was the primary outcome; duration of blockade and tracheal intubating conditions were also measured. The group allocation and study drugs were coded and concealed until statistical analyses were completed. The magnesium and prime group had the shortest mean (SD) onset time (55 (16) s; p < 0.001), and best tracheal intubating conditions (p < 0.05). No statistical difference was found for the duration of blockade. As for adverse events, a burning or heat sensation was reported in eight (35%) and six (26%) patients in the magnesium and magnesium and prime groups, respectively. The combination of magnesium sulphate and rocuronium priming accelerated the onset or neuromuscular blockade and improved rapid‐sequence intubating conditions, compared with either magnesium sulphate or priming used alone.     

Cardiopulmonary exercise testing: arm crank vs cycle ergometry

This pilot study compared oxygen consumption during arm crank and cycle ergometer tests in 15 women. The mean (SD) peak oxygen consumption was less with arm cranking (25 (5) ml.kg^?1.min^?1) than with cycling (40 (7) ml.kg^?1.min^?1), p < 0.0001. The mean (SD) anaerobic threshold was less with arm cranking (13 (2) ml.kg^?1.min^?1) than with cycling (20 (4) ml.kg^?1.min^?1), p < 0.0001. There was moderate correlation, r² = 0.60, between the anaerobic thresholds determined by arm and leg exercise, p = 0.0007. This study suggests that arm crank cardiopulmonary exercise testing could be used for pre‐operative assessment in those unable to cycle.     

A comparison of single‐dose dexmedetomidine or propofol on the incidence of emergence delirium in children undergoing general anaesthesia for magnetic resonance imaging

Emergence delirium is a significant problem in children regaining consciousness following general anaesthesia. We compared the emergence characteristics of 120 patients randomly assigned to receive a single intravenous dose of dexmedetomidine 0.3 μg.kg^?1, propofol 1 mg.kg^?1, or 10 ml saline 0.9% before emerging from general anaesthesia following a magnetic resonance imaging scan. Emergence delirium was diagnosed as a score of 10 or more on the Paediatric Anaesthesia Emergence Delirium scale. The incidence of emergence delirium was 42.5% in the dexmedetomidine group, 33.3% in the propofol group and 41.5% in the saline group (p = 0.671). Three patients in the dexmedetomidine group, none in the propofol group and two in the saline group required pharmacological intervention for emergence delirium (p = 0.202). Administration of neither dexmedetomidine nor propofol significantly reduced the incidence, or severity, of emergence delirium. The only significant predictor for emergence delirium was the time taken to awaken from general anaesthesia, with every minute increase in wake‐up time reducing the odds of emergence delirium by 7%.     

Analgesic efficacy of ketamine and magnesium after laparoscopic sleeve gastrectomy: A randomized,double-blind,placebo-controlled trial

BackgroundKetamine and magnesium are antagonists of the N-methyl-d-aspartate receptor, and are valuable adjuvants for multimodal analgesia and opioid sparing. Data are limited regarding the opioid sparing efficacy of the combined intraoperative application of these agents in laparoscopic bariatric surgery. The objective of this study was to compare the postoperative opioid sparing properties of a single intraoperative dose of ketamine versus a combination of single doses of ketamine and magnesium after laparoscopic gastric sleeve resection in bariatric patients.MethodsOne hundred and twenty- six patients were randomly assigned to receive single boluses of ketamine alone 0.5 mg kg⁻¹ IV (ketamine group); combined ketamine bolus of 0.5 mg kg⁻¹ IV and magnesium 2 g IV (ketamine and magnesium group); or placebo. Opioid consumption at 24 h (in morphine equivalents); pain at rest; postoperative nausea and vomiting impact score; sedation scores; and trends of transcutaneous carbon-di-oxide values were analysed.ResultsThe median (inter-quartile range [range]) morphine consumption at 24 h were 32 (24–47 [4.8–91]) mg in the ketamine group, 37 (18–53 [1–144]) mg in the ketamine and magnesium group, and 26 (21–36 [5–89]) mg in the control group and were not significantly different between the groups. There were no differences for all other outcomes examined.ConclusionCombined single intraoperative bolus doses of ketamine and magnesium did not result in postoperative opioid sparing after laparoscopic gastric sleeve resection.     

Intrathecal vs intravenous magnesium as an adjuvant to bupivacaine spinal anesthesia for total hip arthroplasty

BackgroundThe aim of this study was to investigate the effect of intravenous infusion vs intrathecal magnesium sulfate during spinal anesthesia on postoperative pain, analgesic consumption, and intraoperative blood loss on patients undergoing total hip arthroplasty surgery.MethodsIn this prospective randomized controlled study, 75 adult patients, ASA physical status I and II scheduled for total hip arthroplasty, were included and randomized into three groups. Patients in Group I (control) received spinal anesthesia with hyperbaric bupivacaine and fentanyl. In Group II (IT Mg), 50 mg of magnesium sulfate was added to bupivacaine and fentanyl. In Group III (IV Mg), after induction of spinal anesthesia as in group I, a bolus dose of i.v. magnesium sulfate 40 mg kg^?1 was injected over 10 min, followed by continuous infusion of 15 mg kg^?1 h^?1 till the end of surgery. Arterial blood pressure, heart rate, electrocardiography, and O₂ saturation were continuously monitored. Onset, duration of sensory and motor block, and postoperative pain scores were assessed. Serum magnesium concentrations were checked before induction of anesthesia, immediately after surgery, at 6 h and 24 h after surgery. Total analgesic consumption and intraoperative blood loss were calculated.ResultsThere were no significant differences between the study groups in terms of onset time and maximum sensory level achieved, as well as onset and duration of motor block. Postoperative pain scores and 24 h analgesic consumption were lower in group II and III with insignificant differences between them. Intraoperative blood loss was significantly lower in group III. Postoperative Mg levels were higher in group III, without significant side effects.ConclusionsBoth i.v. infusion and intrathecal injection of Mg sulfate improved postoperative analgesia after total hip replacement. In addition, i.v. infusion of Mg sulfate reduced intraoperative blood loss.     

Postoperative morphine concentration in infants with or without biliary atresia and its association with hepatic blood flow

We measured pre‐operative hepatic blood flow and postoperative morphine concentration in infants with or without biliary atresia. Thirty‐four infants (0–3 months) with biliary atresia undergoing portoenterostomy (Kasai operation) were included and hepatic blood flow was assessed by magnetic resonance imaging before surgery in 12 of them. Sixteen subjects (0–3 months) without liver disease undergoing abdominal or pelvic surgery acted as controls and six of them had hepatic blood flow assessed. Intravenous morphine (8 μg.kg^?1.h^?1) was administered to all patients postoperatively. The median (IQR [range]) relative hepatic blood flow was 3.51 (2.72–3.88 [1.68–4.43]) with and 3.15 (2.66–4.42 [2.30–5.01]) without biliary atresia (p = 0.851). The median (IQR [range]) morphine concentration after 24 h infusion was 5.9 (4.5–16.4 [2.9–42.2]) ng.ml^?1 and 6.4 (3.2–12.0 [1.9–48.6]) ng.ml^?1, respectively (p = 0.460). An inverse regression relation was found between the morphine concentration and the hepatic perfusion index (R² = 0.519, p = 0.001). Compensatory increases in hepatic arterial blood flow maintain the total hepatic blood flow in infants with biliary atresia.     

Isotonic saline in elderly men: an open‐labelled controlled infusion study of electrolyte balance,urine flow and kidney function

Isotonic saline is a widely‐used infusion fluid, although the associated chloride load may cause metabolic acidosis and impair kidney function in young, healthy volunteers. We wished to examine whether these effects also occurred in the elderly, and conducted a crossover study in 13 men with a mean age of 73 years (range 66–84), who each received intravenous infusions of 1.5 l of Ringer's acetate and of isotonic saline. Isotonic saline induced mild changes in plasma sodium (mean +1.5 mmol.l^?1), plasma chloride (+3 mmol.l^?1) and standard bicarbonate (?2 mmol.l^?1). Three hours after starting the infusions, 68% of the Ringer's acetate and 30% of the infused saline had been excreted (p < 0.01). The glomerular filtration rate increased in response to both fluids, but more after the Ringer's acetate (p < 0.03). Pre‐infusion fluid retention, as evidenced by high urinary osmolality (> 700 mOsmol.kg^?1) and/or creatinine (> 7 mmol.l^?1), was a strong factor governing the responses to both fluid loads.     

Fetal effects of combined spinal‐epidural vs epidural labour analgesia: a prospective,randomised double‐blind study

We have compared fetal heart rate patterns, Apgar scores and umbilical cord gas values following initiation of labour analgesia using either combined spinal‐epidural or epidural. One hundred and fifteen healthy women requesting neuraxial analgesia in the first stage of labour were randomly assigned to receive either combined spinal‐epidural (n = 62) or epidural analgesia (n = 53). Fetal heart rate traces, recorded for 30 min before and 60 min after neuraxial block, were categorised as normal, suspicious or pathological according to national guidelines. Sixty‐one fetal heart rate tracings were analysed in the combined spinal‐epidural group and 52 in the epidural group. No significant differences were found in fetal heart rate patterns, Apgar scores or umbilical artery and vein acid‐base status between groups. However, in both combined spinal‐epidural and epidural groups, there was a significant increase in the incidence of abnormal fetal heart rate patterns following neuraxial analgesia (p < 0.0001); two before compared with eight after analgesia in the combined spinal‐epidural group and zero before compared with 11 after in the epidural group. These changes comprised increased decelerations (p = 0.0045) (combined spinal‐epidural group nine before and 14 after analgesia, epidural group four before and 16 after), increased late decelerations (p < 0.0001) (combined spinal‐epidural group zero before and seven after analgesia, epidural group zero before and eight after), and a reduction in acceleration rate (p = 0.034) (combined spinal‐epidural group mean (SD) 12.2 (6.7) h^?1 before and 9.9 (6.1) h^?1 after analgesia, epidural group 11.0 (7.3)  h^?1 before and 8.4 (5.9) h^?1 after). These fetal heart rate changes did not affect neonatal outcome in this healthy population.     

A pilot multicentre randomised controlled trial of lidocaine infusion in women undergoing breast cancer surgery

Chronic postoperative pain is common after breast cancer surgery. Peri-operative lidocaine infusion may prevent the development of chronic postoperative pain, but a large-scale trial is required to test this hypothesis. It is unclear whether a pragmatic, multicentre trial design that is consistent with expert guidance, addresses the limitations of previous studies, and overcomes existing translational barriers is safe, effective and feasible. We conducted a double-blind, randomised controlled pilot study in 150 patients undergoing breast cancer surgery across three hospitals in Western Australia. Patients received lidocaine, or equivalent volumes of saline, as an intravenous bolus (1.5 mg.kg^-1) and infusion (2 mg.kg^-1.h^-1) intra-operatively, and a subcutaneous infusion (1.33 mg.kg^-1.h^-1) postoperatively for up to 12 h on a standard surgical ward, with novel safety monitoring tools in place. The co-primary outcomes were: in-hospital safety events; serum levels of lidocaine during intravenous and subcutaneous infusion; and annualised enrolment rates per site with long-term data capture. In-hospital safety events were rare, and similar in the placebo and lidocaine arms (3% vs. 1%). Median (IQR [range]) serum lidocaine levels during intravenous (2.16 (1.74–2.83 [1.12–6.06]) µg.ml^-1, n = 41) and subcutaneous (1.52 (1.28–1.83 [0.64–2.85]) µg.ml^-1, n = 48) infusion were comparable with previous trials reporting improved pain outcomes. Annualised enrolment approximated 50 patients per site per year, with high levels of protocol adherence and ≥ 99% capture of outcomes at 3 and 6 months. The adjusted odds ratio (95%CI) for postoperative pain at 6 months in the lidocaine arm was 0.790 (0.370–1.684). We conclude that this trial, as designed, is safe, effective and feasible in patients undergoing breast cancer surgery, and a larger-scale trial is planned.     

The effect of a forced‐air warming blanket on patients' end‐tidal and transcutaneous carbon dioxide partial pressures during eye surgery under local anaesthesia: a single‐blind,randomised controlled trial

Surgical drapes used during eye surgery are impermeable to air and hence risk trapping air underneath them. We investigated the effect of a forced‐air warming blanket on carbon dioxide accumulation under the drapes in patients undergoing eye surgery under local anaesthesia without sedation. Forty patients of ASA physical status 1 and 2 were randomly assigned to either the forced‐air warmer (n = 20) or a control heated overblanket (n = 20). All patients were given 1 l.min^?1 oxygen. We measured transcutaneous and end‐tidal carbon dioxide partial pressures, heart rate, arterial pressure, respiratory rate, temperature and oxygen saturation before and after draping, then every 5 min thereafter for 30 min. The mean (SD) transcutaneous carbon dioxide partial pressure in the forced‐air warming group stayed constant after draping at 5.7 (0.2) kPa but rose to a maximum of 6.4 (0.4) kPa in the heated overblanket group (p = 0.0001 for the difference at time points 15 min and later). We conclude that forced‐air warming reduces carbon dioxide accumulation under the drapes in patients undergoing eye surgery under local anaesthesia.