Cardiac output monitoring with thermodilution pulse-contour analysis vs. non-invasive pulse-contour analysis

Intravenous fluid boluses guided by changes in stroke volume improve some outcomes after major surgery, but invasive measurments may limit use. From October 2016 to May 2018, we compared the agreement and trending ability of a photoplethysmographic device (Clearsight) with a PiCCO, calibrated by thermodilution, for haemodynamic variables in 20 adults undergoing major elective surgery. We analysed 4519 measurement pairs, including before and after 68 boluses of 250 ml crystalloid. The bias and precision of stroke volume measurement by Clearsight were −0.89 ± 4.78 ml compared with the invasive pulse-contour cardiac output device. The coefficient of agreement for stroke volume variation after fluid boluses between the two devices was 0.79 (‘strong’). Fluid boluses that increased stroke volume by ≥ 10% increased mean absolute volume (SD) and mean percentage (SD) stroke volume measurements similarly for the invasive pulse-contour cardiac output and Clearsight devices: 9 (4) ml vs. 8 (4) ml and 16% (8%) vs. 15% (10%), respectively, p > 0.05. The non-invasive Clearsight pulse-contour analysis was similar to an invasive pulse-contour device in measuring absolute and changing stroke volumes during major surgery.     

Efficacy of erector spinae plane block for analgesia in breast surgery: a systematic review and meta-analysis

The erector spinae plane block is a new regional anaesthesia technique that provides truncal anaesthesia for breast surgery. This systematic review and meta-analysis was undertaken to determine if the erector spinae plane block is effective at reducing pain scores and opioid consumption after breast surgery. This study also evaluated the outcomes of erector spinae plane blocks compared with other regional blocks. PubMed, Embase, Scopus, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov were searched. We included randomised controlled trials reporting the use of the erector spinae plane block in adult breast surgery. Risk of bias was assessed with the revised Cochrane risk-of-bias tool. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework was used to assess trial quality. Thirteen randomised controlled trials (861 patients; 418 erector spinae plane block, 215 no blocks, 228 other blocks) were included. Erector spinae plane block reduced postoperative pain compared with no block: at 0-2 hours (mean difference (95% CI) −1.63 (−2.97 to −0.29), 6 studies, 329 patients, high-quality evidence, I² = 98%, p = 0.02); at 6 hours (mean difference (95% CI) −0.90 (−1.49 to −0.30), 5 studies, 250 patients, high-quality evidence, I² = 91%, p = 0.003); at 12 hours (mean difference (95% CI) −0.46 (−0.67 to −0.25), 5 studies, 250 patients, high-quality evidence, I² = 58%, p < 0.0001); and at 24 hours (mean difference (95% CI) −0.50 (−0.70 to −0.30), 6 studies, 329 patients, high-quality evidence, I² = 76%, p < 0.00001). Compared with no block, erector spinae plane block also showed significantly lower postoperative oral morphine equivalent requirements (mean difference (95% CI) −21.55mg (−32.57 to −10.52), 7 studies, 429 patients, high-quality evidence, I² = 99%, p = 0.0001). Separate analysis of studies comparing erector spinae plane block with pectoralis nerve block and paravertebral block showed that its analgesic efficacy was inferior to pectoralis nerve block and similar to paravertebral block. The incidence of pneumothorax was 2.6% in the paravertebral block group; there were no reports of complications of the other blocks. This review has shown that the erector spinae plane block is more effective at reducing postoperative opioid consumption and pain scores up to 24 hours compared with general anaesthesia alone. However, it was inferior to the pectoralis nerve block and its efficacy was similar to paravertebral block. Further evidence, preferably from properly blinded trials, is required to confirm these findings.     

A comparison of a prototype electromyograph vs. a mechanomyograph and an acceleromyograph for assessment of neuromuscular blockade

The extent of neuromuscular blockade during anaesthesia is frequently measured using a train-of-four stimulus. Various monitors have been used to quantify the train-of-four, including mechanomyography, acceleromyography and electromyography. Mechanomyography is often considered to be the laboratory gold standard of measurement, but is not commercially available and has rarely been used in clinical practice. Acceleromyography is currently the most commonly used monitor in the clinical setting, whereas electromyography is not widely available. We compared a prototype electromyograph with a newly constructed mechanomyograph and a commercially available acceleromyograph monitor in 43 anesthetised patients. The mean difference (bias; 95% limits of agreement) in train-of-four ratios was 4.7 (−25.2 to 34.6) for mechanomyography vs. electromyography; 14.9 (−13.0 to 42.8) for acceleromyography vs. electromyography; and 9.8 (−31.8 to 51.3) for acceleromyography vs. mechanomyography. The mean difference (95% limits of agreement) in train-of-four ratios between opposite arms when using electromyography was −0.7 (−20.7 to 19.3). There were significantly more acceleromyography train-of-four values > 1.0 (23%) compared with electromyography or mechanomography (2–4%; p < 0.0001). Electromyography most closely resembled mechanomyographic assessment of neuromuscular blockade, whereas acceleromyography frequently produced train-of-four ratio values > 1.0, complicating the interpretation of acceleromyography results in the clinical setting.     

Validation of cardiac output measurement with the LiDCO™ pulse contour system in patients with impaired left ventricular function after cardiac surgery

After cardiac surgery, patients with low left ventricular ejection fraction probably benefit the most from accurate monitoring of continuous cardiac output. Thirty patients with impaired ventricular function were studied, and intermittent bolus thermodilution and continuous pulse contour (LiDCO plus^TM) cardiac output compared. Following lithium dilution calibration, a total of 220 paired results were recorded. Thermodilution and LiDCO measurements ranged from 2.3 to 11.0 and 2.6 to 10.8 l.min^?1, respectively. Corresponding means (SD) were 6.1 (1.6) and 6.2 (1.9) l.min^?1, with coefficients of variance of 26 and 31%, respectively. The correlation coefficient was 0.82, bias 0.28 l.min^?1 with upper and lower limits of agreement 1.96 and ?1.41 l.min^?1; the percentage error was 27%. LiDCO showed good correlation, marginal bias and acceptable limits of agreement and percentage error. It could therefore potentially replace thermodilution as a means of measuring cardiac output in the ICU, particularly when determination of pulmonary artery pressure is not required.     

Pléthysmographie électrique d'impédance et thermodilution: Etude comparative chez l'homme de deux méthodes de mesure du débit cardiaque

The measurement of cardiac output by electrical impedance plethysmography (non invasive technic) seems to be attractive but is still the subject of a certain number of critics. The authors have tried to compare it with a method which validity is well documented, the thermodilution. By these two methods, 87 measures of cardiac output have been performed in 14 hospitalized patients in intensive care, attained of various affections but exempts of cardiac or pulmonary lesions and in stable hemodynamic state. The stroke volume measured by electrical impedance plethysmography is calculated using Kubicek's formula : SV = ? (L²/Zo²) (dz/dt min) t. Results were as follows : absence of significative difference between the coefficients of variation of each series of measures (coefficient of mean variation, 5,6 ± 3,4 p. cent for impedance and 3,8 ± 3,2 p. cent for thermodilution); absence of significative difference between the mean values of cardiac output (7,59 ± 2,69 l.min^?1 for impedance and 7,72 ± 1,99 l . min^?1 for thermodilution); highly significant correlation between values for cardiac output obtained by each of these two methods (r = 0,804; n = 87; p <0,001). The authors conclude that in patients in intensive care whose pulmonary or cardiovascular system is not in critical situation, the electrical impedance plethysmography appear as a secure method for cardiac output measurement. However its generalisation still require other works.     

Peripartum cardiomyopathy: postpartum decompensation and use of non-invasive cardiac output monitoring

The utility of a non-invasive cardiac output monitor (NICOM™) in guiding the peripartum management and identification of postpartum complications in a patient with severe peripartum cardiomyopathy is reported. A 31-year-old nulliparous woman at 35 weeks of gestation presented with a three-week history of worsening dyspnea and progressive functional deterioration. A transthoracic echocardiogram showed severe left ventricular systolic dysfunction with an ejection fraction <20%. Cardiac status was monitored using NICOM™ during labor and delivery. The baseline values were: cardiac output 5.3 L/min, total peripheral resistance 1549 dynes.sec/cm⁵, stroke volume 42.1 mL and stroke volume variation 18%. She received early epidural analgesia during labor, titrated slowly with a loading dose of 0.0625% bupivacaine 10 mL and fentanyl 25 μg, followed by patient-controlled epidural analgesia (0.0625% bupivacaine with fentanyl 2 μg/mL, infusion at 10 mL/h, bolus dose 5 mL and lockout interval 10 min). After epidural drug administration, total peripheral resistance decreased, cardiac output increased, and satisfactory analgesia was obtained. She had an uneventful vaginal delivery with a forceps-assisted second stage after prophylactic administration of furosemide 20 mg. NICOM™ was discontinued after delivery. Fifteen hours post-delivery, the patient developed cardiogenic shock, which resolved after aggressive therapy with inotropes and furosemide. NICOM™ can be used to guide treatment during labor and delivery in patients with critical peripartum cardiomyopathy. We suggest that use of NICOM™ be extended into the postpartum period to detect signs of cardiac decompensation in such patients.     

Comparison of the effects of hemodialysis and hemodiafiltration on left ventricular hypertrophy in end-stage renal disease patients: A systematic review and meta-analysis

Whether hemodiafiltration (HDF) is better than conventional hemodialysis (HD) in improving left ventricular hypertrophy (LVH), defined as reduction of the left ventricular mass index (LVMi) and increasing the ejection fraction (EF), is unclear. A systematic literature search was performed. Primary outcome was the mean difference between pre- and post-procedural LVMi. Secondary outcome was the mean difference in EF. Seven studies with a total of 845 patients were included. The pooled mean difference between pre-and post-procedural LVMi was −8.0 g/m² (95% confidence interval [CI] −13.1, −2.8). On subgroup analysis, the mean differences between pre- and post-procedural LVMi for HD and HDF were −6.7 g/m² (95% CI −14.5, 1.1) and −9.3 g/m² (95% CI −16.3, −2.3), respectively (P for subgroups = .62). Pooled mean difference between pre- and post-procedural EF was 2.4% (95% CI −1.8, 6.5). On subgroup analysis, the mean differences between pre- and post-procedural EF for HD and HDF were 3.6% (95% CI −2.7, 9.8) and 2.0% (95% CI 2.9, 6.8), respectively (P for subgroups = .68). On meta-regression, age (Beta −0.35 ± 0.05, P < .001) and longer dialysis duration (Beta −0.12 ± 0.02, P < .001) were associated with lower mean difference between pre-and post-procedural EF. No significant effects on changes in LVMi and EF were observed with HDF compared with conventional HD.     

Level of agreement between cardiac output measurements using Nexfin® and thermodilution in morbidly obese patients undergoing laparoscopic surgery

Morbidly obese patients are at increased risk of intra‐operative haemodynamic instability, which may necessitate intensive monitoring. Non‐invasive monitoring is increasingly used to measure cardiac output; however, it is unknown whether the weight‐based algorithm utilised in these devices is applicable to patients with morbid obesity. We compared the level of agreement and trending ability of non‐invasive cardiac output measurements (Nexfin^®) with the gold‐standard thermodilution technique in 30 morbidly obese patients undergoing laparoscopic surgery. Bland–Altman analysis revealed a mean (SD) bias of 0.60 (1.62) l.min^?1 (limits of agreement ?2.67 to 3.86 l.min^?1) and the precision error was 46%. Polar plot analysis resulted in an angular bias of 2.61°, radial limits of agreement of ?60.08° to 49.82° and angular concordance rate was 77%. Both agreement and trending were outside the Critchley criteria for the comparison of cardiac output devices with a gold‐standard. Nexfin has an unacceptable level of agreement compared with thermodilution for cardiac output measurement in morbidly obese patients.     

A meta‐analysis of the accuracy and precision of the ultrasonic cardiac output monitor (USCOM)

The ultrasonic cardiac output monitor is a non‐invasive, continuous‐wave Doppler monitor that can be used to measure cardiac output. Its accuracy and precision in peri‐operative and critical care has been assessed with varied results. We conducted a meta‐analysis to calculate a pooled mean bias, precision and percentage error for this device. Six studies were suitable for inclusion into a pooled parametric analysis consisting of 320 measurements. The mean weighted bias was ?0.39 l.min^?1 (95% CI ?0.25 to ?0.53 l.min^?1), precision 1.27 l.min^?1 and percentage error 42.7% (95% CI 38.5?46.9%). The ultrasonic cardiac output monitor achieved similar agreement with bolus thermodilution to that of other minimally invasive methods of peri‐operative cardiac output monitoring, and may have a useful role in cardiac output monitoring.     

Heart rate and cardiac output after atropine in anaesthetised infants and children

Purpose

Heart rate is considered to be a major determinant of cardiac output in infants and small children but the relationships between age, heart, rate and cardiac output in humans have never been clearly established. This study was designed to determine the change in cardiac output following atropine iv to anaesthetised infants and small children. Methods: Following-,Institutional Ethics Committee approval and written-informed consent, 20 ASA l or ll unpremeditated patients aged from 1 to 36 mo were studied. Anaesthesia was induced with 5 mg · kg^?1 thiopentone, 2 μg · kg^?1 fentanyl and maintained with halothane 0.5% in nitrous oxide 66% in oxygen. Vecuronium, 0.1 mg · kg^?1 was used to provide muscular relaxation. Cardiac output was measured by non-invasive transthoracic blind continuous-wave Doppler echocardiography before and after the administration of 0.02 mg·kg^?1 atropine iv.

Resulits

Atropine increased both heart rate and cardiac index by 31.1 ± 12.8% and 29.4 ± 17.3% respectively (P < 0.05). The cardiac index before atropine was 5.1 ± 1.2 L.min^?1m^?2 and the increase after atropine varied widely from 1,4 to 52.1%. Although atropine did not alter the overall stroke index the recorded changes ranged from -20.8 to + 18.0%. There was no association between age and either cardiac index or % change in cardiac index after atropine. However, there was a positive but weak correlation between percentage change in heart rate and cardiac output (r²=0.46).

Conclusion

Atropine causes a variable increase in cardiac output in infants and children aged between 1 and 36 mo. The change in cardiac,output, considering the limits of the transthoracic echocardiography methodology, suggests that this is related to the increase in heart rate but is not dependent of age.     

Local anaesthetic delivery regimens for peripheral nerve catheters: a systematic review and network meta-analysis

There are numerous possible techniques for delivering local anaesthetic through peripheral nerve catheters. These include continuous infusions, patient-controlled boluses and programmed intermittent boluses. The optimal delivery regimen of local anaesthetic is yet to be conclusively established. In this review, we identified prospective trials of delivery regimens through peripheral nerve catheters. Our primary outcome was visual analogue scale scores for pain at 48 h. Secondary outcomes were: visual analogue scores at 24 h; patient satisfaction scores; rescue opioid use; local anaesthetic consumption; and nausea and vomiting. Network meta-analysis was used to compare these outcomes. Predefined sub-group analyses were performed. Thirty-three studies enrolling 1934 participants were included. In comparison with continuous infusion, programmed intermittent boluses improved visual analogue pain scores at both 48 and 24 h, the weighted mean difference (95%CI) being −0.63 (−1.12 to −0.14), p = 0.012 and −0.48 (−0.92 to −0.03), p = 0.034, respectively. Programmed intermittent boluses also improved satisfaction scores, the weighted mean difference (95%CI) being 0.70 (0.10–1.31), p = 0.023, and reduced rescue opioid use, the weighted mean difference (95%CI) in oral morphine equivalent at 24 h being −23.84 mg (−43.90 mg to −3.77 mg), p = 0.020. Sub-group analysis revealed that these findings were mostly confined to lower limb and truncal catheter studies; there were few studies of programmed intermittent boluses for upper limb catheters. Programmed intermittent boluses may provide optimal delivery of a local anaesthetic through peripheral nerve catheters. Further research is warranted, particularly to delineate the differences between upper and lower limb catheter locations, which will help clarify the clinical relevance of these findings.     

The use of phenylephrine to obtund oxytocin-induced hypotension and tachycardia during caesarean section

BackgroundOxytocin causes clinically significant hypotension and tachycardia. This study examined whether prior administration of phenylephrine obtunds these unwanted haemodynamic effects.MethodsForty pregnant women undergoing elective caesarean section under spinal anaesthesia were randomised to receive either an intravenous 50 μg bolus of phenylephrine (Group P) or saline (Group S) immediately before oxytocin (3 U over 15 s). Systolic blood pressure, diastolic blood pressure, mean arterial pressure and heart rate were recorded using a continuous non-invasive arterial pressure device. Baseline values were averaged for 20 s post-delivery. Between-group comparisons were made of the mean peak changes in blood pressure and heart rate, and the mean percentage changes from baseline, during the 150 s after oxytocin administration.ResultsThe mean ± SD peak percentage change in systolic blood pressure was −16.9 ± 2% in Group P, and −19.0 ± 1.9% in Group S and the estimated mean difference was 2.1% (95% CI −3.5% to 7.8%; P=0.44); corresponding changes in heart rate were 13.5 ± 2.3% and 14.0 ± 1.5% and the mean estimated difference was 0.5% (95% CI −6.0% to 5%; P=0.87). The mean percentage change from the baseline measurements during the 150 s period of measurement was greater for Group S than Group P: systolic blood pressure −5.9% vs −3.4% (P=0.149); diastolic blood pressure −7.2% vs −1.5% (P=0.014); mean arterial pressure −6.8% vs −1.5% (P=0.007); heart rate 2.1% vs −2.4% (P=0.033).ConclusionIntravenous phenylephrine 50 μg immediately before 3 U oxytocin during elective caesarean section does not prevent maternal hypotension and tachycardia.     

The effect of patient ethnicity on the accuracy of peripheral pulse oximetry in patients with COVID-19 pneumonitis: a single-centre,retrospective analysis

Pulse oximetry is used widely to titrate oxygen therapy and for triage in patients who are critically ill. However, there are concerns regarding the accuracy of pulse oximetry in patients with COVID-19 pneumonitis and in patients who have a greater degree of skin pigmentation. We aimed to determine the impact of patient ethnicity on the accuracy of peripheral pulse oximetry in patients who were critically ill with COVID-19 pneumonitis by conducting a retrospective observational study comparing paired measurements of arterial oxygen saturation measured by co-oximetry on arterial blood gas analysis (SaO₂) and the corresponding peripheral oxygenation saturation measured by pulse oximetry (S_pO₂). Bias was calculated as the mean difference between SaO₂ and S_pO₂ measurements and limits of agreement were calculated as bias ±1.96 SD. Data from 194 patients (135 White ethnic origin, 34 Asian ethnic origin, 19 Black ethnic origin and 6 other ethnic origin) were analysed consisting of 6216 paired SaO₂ and S_pO₂ measurements. Bias (limits of agreement) between SaO₂ and S_pO₂ measurements was 0.05% (−2.21–2.30). Patient ethnicity did not alter this to a clinically significant degree: 0.28% (1.79–2.35), −0.33% (−2.47–2.35) and −0.75% (−3.47–1.97) for patients of White, Asian and Black ethnic origin, respectively. In patients with COVID-19 pneumonitis, S_pO₂ measurements showed a level of agreement with SaO₂ values that was in line with previous work, and this was not affected by patient ethnicity.     

手术中用三维经食道超声心动图测量心输出量的准确性和可行性

背景本研究中,我们试图用三维经食道超声心动图（3DTEE）确定心输出量,并评价其在手术中应用的可行性。方法同时用3DTEE和热稀释．法测定20例行心脏手术的患者在临床上稳定的体外循环前期时的心输出量。结果用这2种方法测定心输出量之间的相关系数是0．86。3DTEE的平均偏差是0．27L／min,范围是一1．64—2．17L／min（一致性为±35％）。平均三维数据采集时间为43秒,数据后处理时间为7分钟。结论可以用3DTEE来测量心输出量,并且这种方法在围手术期是可行的。虽然这种方法同热稀释法相比差异有显著性,且一致性较差,但是与热稀释法有很好的相关性。     

Bone lead (Pb) content at the tibia is associated with thinner distal tibia cortices and lower volumetric bone density in postmenopausal women

Conflicting evidence suggests that bone lead or blood lead may reduce areal bone mineral density (BMD). Little is known about how lead at either compartment affects bone structure. This study examined postmenopausal women (N = 38, mean age 76 ± 8, body mass index (BMI): 26.74 ± 4.26 kg/m²) within the Hamilton cohort of the Canadian Multicentre Osteoporosis Study (CaMos), measuring bone lead at 66% of the non-dominant leg and at the calcaneus using ¹⁰⁹Cadmium X-ray fluorescence. Volumetric BMD and structural parameters were obtained from peripheral quantitative computed tomography images (200 μm in-plane resolution, 2.3 ± 0.5 mm slice thickness) of the same 66% site and of the distal 4% site of the tibia length. Blood lead was measured using atomic absorption spectrometry and blood-to-bone lead partition coefficients (P_BB, log ratio) were computed. Multivariable linear regression examined each of bone lead at the 66% tibia, calcaneus, blood lead and P_BB as related to each of volumetric BMD and structural parameters, adjusting for age and BMI, diabetes or antiresorptive therapy. Regression coefficients were reported along with 95% confidence intervals. Higher amounts of bone lead at the tibia were associated with thinner distal tibia cortices (− 0.972 (− 1.882, − 0.061) per 100 μg Pb/g of bone mineral) and integral volumetric BMD (− 3.05 (− 6.05, − 0.05) per μg Pb/g of bone mineral). A higher P_BB was associated with larger trabecular separation (0.115 (0.053, 0.178)), lower trabecular volumetric BMD (− 26.83 (− 50.37, − 3.29)) and trabecular number (− 0.08 (− 0.14, − 0.02)), per 100 μg Pb/g of bone mineral after adjusting for age and BMI, and remained significant while accounting for diabetes or use of antiresorptives. Total lead exposure activities related to bone lead at the calcaneus (8.29 (0.11, 16.48)) and remained significant after age and antiresorptives-adjustment. Lead accumulated in bone can have a mild insult on bone structure; but greater partitioning of lead in blood versus bone revealed more dramatic effects on both microstructure and volumetric BMD.     

Erector spinae plane block for postoperative analgesia in breast and thoracic surgery: A systematic review and meta-analysis

Study objectiveThe erector spinae plane block (ESPB) is a newly defined regional anesthesia technique first introduced in 2016. The aim of this study is to determine its analgesic efficacy compared with non-block care and thoracic paravertebral block (TPVB).DesignWe systematically searched PubMed, Web of Science citation index, Embase, the Cochrane Library, Google Scholar, and ClinicalTrials.gov register searched up to March 2020. We conducted a meta-analysis of randomized controlled trials (RCTs) that compared an ESPB to non-block care or TPVB for postoperative analgesia in breast and thoracic surgery patients. Primary outcome was 24-hour postoperative opioid consumption. Risk of bias was assessed using Cochrane methodology.Results14 RCTs that comprised 1018 patients were included. Seven trials involved thoracic surgery patients and seven included breast surgery patients. Meta-analysis revealed that ESPB significantly reduced 24-hour opioid consumption compared with the non-block groups (−10.5 mg; 95% CI: −16.49 to −3.81; p = 0.002; I² = 99%). Similarly, the finding was consistent in subgroup analysis between the breast surgery (−7.75 mg; 95%CI −13.98 to −1.51; p = 0.01; I² = 97%) and thoracic surgery (−14.81 mg; 95%CI −21.18 to −8.44; p < 0.001; I² = 96%) subgroups. The ESPB significantly reduced pain scores at rest or movement at various time points postoperatively compared with non-block group, and reduced the rate of postoperative nausea and vomiting (OR 0.48; 95%CI 0.27 to 0.86; p = 0.01; I² = 0%). In contrast, there were no significative differences reported in any of the outcomes for ESPB versus TPVB strata.ConclusionsESPB improved analgesic efficacy in breast and thoracic surgery patients compared with non-block care. Furthermore, current literature supported the ESPB offered comparable analgesic efficacy to a TPVB.     

Analgesic efficacy of PECS vs paravertebral blocks after radical mastectomy: A systematic review,meta-analysis and trial sequential analysis

Study objectiveDue to conflicting results published in the literature regarding the analgesic superiority between the paravertebral block and the PECS block, the study objective is to determine which one should be the first line analgesic treatment after radical mastectomy.DesignSystematic review, meta-analysis and trial sequential analysis.SettingOperating room, postoperative recovery area and ward, up to 24 postoperative hours.PatientsPatients scheduled for radical mastectomy under general anaesthesia.InterventionsWe searched five electronic databases for randomized controlled trials comparing any PECS block with a paravertebral block.MeasurementsThe primary outcome was rest pain score (0−10) at 2 postoperative hours, analyzed according to the combination with axillary dissection or not, to account for heterogeneity. Secondary outcomes included rest pain scores, cumulative intravenous morphine equivalents consumption and rate of postoperative nausea and vomiting at 24 postoperative hours.Main resultsEight trials including 388 patients were identified. Rest pain scores at 2 postoperative hours were decreased in the PECS block group, with a mean difference (95%CI) of −0.4 (−0.7 to −0.1), I² = 68%, p = 0.01, and a significant subgroup difference observed between radical mastectomy with (mean difference [95%CI]: 0.0 [−0.2 to 0.2], I² = 0%, p = 1.00), or without axillary dissection (mean difference [95%CI]: −0.7 [−1.1 to −0.4], I² = 40%, p < 0.001; p for subgroup difference < 0.001). All secondary pain-related outcomes were similar between groups. The overall quality of evidence was low.ConclusionsThere is low quality evidence that a PECS block provides marginal postoperative analgesic benefit after radical mastectomy at 2 postoperative hours only, when compared with a paravertebral block, and not beyond.Clinical trial number: PROSPERO – registration number: CRD42019131555.     

Comparison of cardiac output measurements in critically ill patients: FloTrac/Vigileo vs transthoracic Doppler echocardiography

Measurement of cardiac output is an integral part of patient management in the intensive care unit. FloTrac/Vigileo is a continuous cardiac output monitoring device that does not need re-calibration. However its reliability has been questioned in some studies, especially involving surgical patients. In this study, we evaluated the comparability of FloTrac/Vigileo and transthoracic Doppler echocardiography in 53 critically ill patients requiring continuous cardiac output monitoring. Most of these patients had septic or cardiogenic shock. Cardiac output was measured by both FloTrac/Vigileo and transthoracic Doppler echocardiography. The bias and precision (mean and SD) between the two devices was 0.35 +/- 1.35 l/minute. The limits of agreement were -2.3 to 3.0 l/minute (%error = 49.3%). When patients with irregular heart rhythms and aortic stenosis were excluded, the bias and precision was 0.02 +/- 0.80 l/minute (n = 42). The limits of agreement were -1.55 to 1.59 l/minute (%error = 29.5%). Patient demographics (body surface area, gender and age) did not affect the bias, but there was a mild tendency for FloTrac/ Vigileo to register a higher cardiac output at high heart rates. Changes in cardiac output for two consecutive days correlated well between the two methods (r = 0.86; P < 0.001). In summary, with the exceptions of patients with irregular heart rhythms and significant aortic stenosis, FloTrac/Vigileo is clinically comparable to transthoracic Doppler echocardiography in cardiac output measurements in critically ill patients.     

Reliability of alternative devices for postoperative patient temperature measurement: two prospective,observational studies*

Peri-operative hypothermia is associated with significant morbidity, yet limitations exist regarding non-invasive temperature assessment in the post-anaesthesia care unit (PACU). In this prospective study of 100 patients, we aimed to determine the reliability of two commonly used temperature measurement devices, forehead temporal artery temperature and tympanic measurement, in addition to an indwelling urinary catheter with temperature probe, in comparison with the final nasopharyngeal core temperature at the end of surgery. Agreement of forehead measurement with nasopharyngeal temperature showed a mean bias (±95% limits of agreement) of 0.15 °C (±1.4 °C), with a steep slope of the relationship on the Bland–Altman plot of −0.8, indicating a tendency to normalise patient temperature readings to 36.4 °C. Only 54% of hypothermic cases were correctly detected by the forehead measurement device. Agreement of tympanic measurement with nasopharyngeal core temperature measurement was marginally improved with a mean bias of 0.13 °C (95% limits of agreement ±1.15 °C). In contrast, agreement of bladder temperature with nasopharyngeal temperature showed a mean (SD) bias of 0.19 (0.28) °C (95% limits of agreement ±0.54 °C), with a relatively flat line of best fit. We demonstrated that two commonly used temperature measurement devices, forehead temporal artery temperature and tympanic measurement, compared with nasopharyngeal core temperature, were imprecise and unreliable following major surgery. However, the indwelling catheter with temperature sensor was precise and acceptable for continuous core temperature measurement in the PACU.     

Analgesic efficacy of PECS and serratus plane blocks after breast surgery: A systematic review,meta-analysis and trial sequential analysis

Study objectiveTo determine whether pectoral nerves (PECS) blocks provide effective postoperative analgesia when compared with no regional technique in patients undergoing breast surgery.DesignSystematic review, meta-analysis and trial sequential analysis.SettingOperating room, postoperative recovery area and ward, up to 24 postoperative hours.PatientsPatients undergoing breast surgery under general anaesthesia with either PECS block or no regional technique.InterventionsWe searched five electronic databases for randomized controlled trials comparing PECS block with no block or sham injection.MeasurementsThe primary outcome was rest pain scores (analogue scale, 0–10) at 2 h, analysed according to surgery (mastectomy vs other breast surgery) and regional technique (PECS 2 vs other blocks), among others. Secondary outcomes included morphine equivalent consumption, and rate of postoperative nausea and vomiting at 24 h.Main resultsSixteen trials including 1026 patients were identified. Rest pain scores at 2 h were decreased in the PECS blocks group, with a mean (95%CI) difference of −1.5 (−2.0, −1.0); I2 = 93%; p < 0.001, with no differences between surgery (mastectomy, mean difference [95%CI]: −1.8 [−2.4, −1.2], I² = 91%, p < 0.001; other breast surgery, mean difference [95%CI]: −1.1 [−2.1, −0.1], I² = 94%, p = 0.03; p for subgroup difference = 0.25), and regional technique (PECS 2, mean differences [95%CI]: −1.6 [−2.3, −1.0], I² = 94%, p < 0.001; other blocks, mean differences [95%CI]: −1.3 [−2.4, −0.1], I² = 74%, p = 0.04; p for subgroup difference = 0.57). The rate of postoperative nausea and vomiting was reduced from 30.8% (95%CI: 25.7%, 36.3%) to 18.7% (95%CI, 14.4%, 23.5%; p = 0.01). Similarly, secondary outcomes were significantly improved in the PECS blocks group. The overall quality of evidence was moderate-to-high.ConclusionsThere is moderate-to-high level evidence that PECS blocks provide postoperative analgesia after breast surgery when compared with no regional technique and reduce rate of PONV. This might provide the most benefit to those at high-risk of postoperative pain.