Incidental detection of paradoxical air embolism with a transoesophageal Doppler probe inserted for measuring descending aortic blood flow

We present a case of paradoxical air embolism in a patient undergoingneurosurgery of the posterior fossa in the sitting position.Paradoxical air embolism was detected in the descending aortaby a transoesophageal Doppler probe, which was inserted primarilyfor non-invasive haemodynamic monitoring. The patient sufferedno serious complications of paradoxical air embolism and recoveredwell. We suggest that paradoxical air embolism can be detectedintraoperatively not only by transoesophageal echocardiography,but also with a transoesophageal Doppler probe. Br J Anaesth 2003; 90: 520–2     

Cerebral embolization during cardiac surgery: impact of aortic atheroma burden

Background. Aortic atheromatous disease is known to be associatedwith an increased risk of perioperative stroke in the settingof cardiac surgery. In this study, we sought to determine therelationship between cerebral microemboli and aortic atheromaburden in patients undergoing cardiac surgery. Methods. Transoesophageal echocardiographic images of the ascending,arch and descending aorta were evaluated in 128 patients todetermine the aortic atheroma burden. Transcranial Doppler (TCD)of the right middle cerebral artery was performed in order tomeasure cerebral embolic load during surgery. Using multivariatelinear regression, the numbers of emboli were compared withthe atheroma burden. Results. After controlling for age, cardiopulmonary bypass timeand the number of bypass grafts, cerebral emboli were significantlyassociated with atheroma in the ascending aorta (R²=0.11, P=0.02)and aortic arch (P=0.013). However, there was no associationbetween emboli and descending aortic atheroma burden (R²=0.05,P=0.20). Conclusions. We demonstrate a positive relationship betweenTCD-detected cerebral emboli and the atheromatous burden ofthe ascending aorta and aortic arch. Previously demonstratedassociations between TCD-detectable cerebral emboli and adversecerebral outcome may be related to the presence of significantaortic atheromatous disease. Br J Anaesth 2003; 91: 656–61     

Pathophysiology and clinical implications of perioperative fluid excess

Br J Anaesth 2002; 89: 622–32     

Assessment of preoperative fluid depletion using bioimpedance analysis

Background. Fluid depletion during the perioperative periodis associated with poorer outcome. Non-invasive measurementof total body water by bioimpedance may enable preoperativefluid depletion and its influence on perioperative outcome tobe assessed. Methods. Weight and foot bioimpedance were recorded under standardizedconditions in patients undergoing bowel preparation (n=43) orday surgery (n=44). Fifteen volunteers also followed standardnil-by-mouth instructions on two separate occasions to assessthe variabilities of weight and bioimpedance over time. Results. Body weight fell by 1.27 kg (95% CI 1.03–1.50kg; P<0.0001) and foot bioimpedance increased by 51 ohm afterbowel preparation (95% CI 36–66; P<0.0001). Weightchange after the nil-by-mouth period in day-surgery patients(mean –0.22 kg, 95% CI –0.05 to –0.47 kg;P=0.07) correlated (r=–0.46; P=0.005) with an increasein bioimpedance (16 ohms, 95% CI 5–27 ohms; P=0.01). Nodifference between two separate bioimpedance measurements wasseen in the volunteer group. Conclusions. Further work is warranted to determine if bioimpedancechanges may serve as a useful indicator of perioperative fluiddepletion. Br J Anaesth 2004; 92: 134–6     

Reduction of prolonged postoperative hospital stay after laparoscopic surgery for colorectal carcinoma

Background In evaluating the quality of laparoscopic surgery (LS) for colorectal carcinoma, many previous reports have used median or range values to assess the length of postoperative hospital stay and to show the complication and conversion rates separately. However, with this method, it is impossible to assess the proportion of patients who required prolonged postoperative hospital stay because of perioperative morbidities. This study investigated the proportion of patients who benefited from LS as minimally invasive surgery by assessing the percentage of patients who required prolonged postoperative hospital stay because of major perioperative morbidities. Methods A review of 202 patients who underwent LS for colorectal carcinoma at the authors’ hospital between January 2002 and December 2004 was performed. Short-term outcomes were compared among the patients who underwent LS in 2002, 2003, and 2004. Results No significant differences were observed in baseline characteristics among the groups, and all the procedures in this study were completed laparoscopically. There were no significant differences in the operative times and intraoperative blood losses among the groups. Most of the patients resumed liquid intake on postoperative day 1 and solid food on day 3. However, there was a significant difference in the rate of postoperative prolonged hospital stays by year of surgery. In 2004, 97.3% of the patients (72/74) undergoing LS could be discharged to home within 8 days postoperatively. Major complications occurred at a low rate of 1.4% (1/74) in 2004. Regarding the reasons for prolonged postoperative hospital stay, inappropriate judgment of the physician in charge, based primarily on requests from patients without medical necessity, disappeared in 2004. Conclusions When LS is performed properly by specialists who have accumulated sufficient experience in both LS and conventional open surgery for colorectal carcinoma, up to 97% of patients undergoing LS can benefit from minimally invasive surgery.     

Evaluation of corrected flow time in oesophageal Doppler as a predictor of fluid responsiveness

Background: Corrected flow time (FTc) by oesophageal Doppler is consideredto be a ‘static’ preload index. We evaluated theability of FTc to predict fluid responsiveness and comparedthis with the abilities of other preload indices, such as pulsepressure variation (PPV), central venous pressure (CVP), andleft ventricular end-diastolic area index (LVEDAI). Methods: Twenty neurosurgical patients were studied. After inductionof anaesthesia, FTc, PPV, LVEDAI, CVP, and stroke volume index(SVI) were measured before and 12 min after fluid loading with6% hydroxyethyl starch solution (7 ml kg^–1). Respondersand non-responders were defined as those patients with an SVIincrease 10% or < 10% after fluid loading, respectively.Pearson's correlation was used to assess correlations betweenchanges in SVI and initial haemodynamic variables. Receiveroperating characteristic (ROC) curves were constructed and comparedto evaluate the overall performance of preload indices (FTc,PPV, LVEDAI, and CVP) in terms of predicting fluid responsiveness. Results: FTc and PPV before fluid loading differed between responders(n = 11) and non-responders (n = 9), and correlated with changesin SVI (r = –0.515 and r = 0.696, respectively), whichwas opposite to that observed for CVP or LVEDAI. Areas underROC curves for FTc [0.944 (SD 0.058)] and PPV [0.909 (0.069)]were significantly greater than those for CVP [0.540 (0.133),P < 0.001] and LVEDAI [0.495 (0.133), P < 0.001]. Theoptimal threshold value given by ROC analysis was 357 ms forFTc. Conclusions: In this study, FTc predicted fluid responsiveness. However,FTc should be used in conjunction with other clinical information.     

Near-patient testing for coagulopathy after cardiac surgery

Background. We assessed the accuracy and precision of a newnear-patient testing system (Hemochron^® Response) by measuringprothrombin time and activated partial thromboplastin time (PTand APTT) in 50 patients undergoing cardiac surgery using cardiopulmonarybypass and comparing the results with laboratory assays. Methods. Blood samples were taken at the beginning of surgeryand the PT and APTT was measured both in the laboratory andby the Hemochron^® Response. The tests were repeated 30 minafter reversal of heparin with protamine. Results. Before bypass, the bias for PT was only +0.34, withsmall 95% limits of agreement. Making the same measurementsafter bypass, the Hemochron^® Response under-read and thebias was –3.27, with an increase of the 95% limits ofagreement. With the APTT, the bias and the 95% limits of agreementwere greater before bypass, and became even wider after bypass. Conclusions. We found good agreement in the PT and clinicallyacceptable levels of agreement in the APTT during the pre-bypassperiod. After bypass, bias became greater for both PT and APTTand the limits of agreement could be clinically unacceptable. Br J Anaesth 2003; 90: 499–501     

Cerebral haemodynamics in pregnancy and pre-eclampsia as assessed by transcranial Doppler ultrasonography

Background. Altered cerebral circulation, as reported duringnormal pregnancy, and in patients with pre-eclampsia, can beassociated with changes in cerebral vascular reactivity and/orcerebral autoregulation. The aim of our study was to performa comparative assessment of cerebral haemodynamics, includingvascular reactivity and autoregulation, in pre-eclamptic patients,healthy pregnant women, and healthy non-pregnant women. Methods. Thirty patients with pre-eclampsia were recruited.Age- and height-matched healthy pregnant (n=30) and non-pregnantcontrol (n=30) groups were also recruited. Monitoring includedtranscranial Doppler ultrasonography, end-tidal carbon dioxideand non-invasive arterial pressure measurement. Cerebral autoregulationwas assessed by performing the transient hyperaemic response(THR) test. The cerebrovascular reactivity to carbon dioxide(CRCO₂) was assessed by measuring middle cerebral artery bloodflow velocity (MCAFV) after induced changes in end-tidal carbondioxide. Estimated cerebral perfusion pressure (eCPP) and criticalclosing pressure (CrCP) were calculated using established formulae.Statistical analysis included ANOVA with Tukey’s pairwisecomparisons. Results. Mean arterial pressure (MAP) was increased in pre-eclampsia(P<0.05). Mean MCAFV was lower in healthy pregnancy (P<0.05),but in pre-eclampsia it was similar to the non- pregnant group.When compared with the non-pregnant group, mean eCPP was higherin the healthy pregnant and pre-eclamptic groups (P<0.05).There were no meaningful differences in cerebral autoregulationor CRCO₂. Conclusions. Healthy pregnancy increases eCPP, presumably bydecreasing CrCP. In pre-eclampsia, eCPP is maintained at thesame level as in healthy pregnancy despite an increased MAP.Pre-eclampsia has no significant effect on cerebral autoregulationor CRCO₂. Br J Anaesth 2002; 89: 687–92     

Epidural analgesia compared with peripheral nerve blockade after major knee surgery: a systematic review and meta-analysis of randomized trials

The relative analgesic efficacy and side-effect profile of peripheral nerve blockade (PNB) techniques compared with lumbar epidural analgesia for major knee surgery is unclear. We undertook a systematic review and meta-analysis of all randomized trials comparing epidural analgesia with PNB for major knee surgery. Eight studies were identified that had enrolled a total of 510 patients of whom 464 (91%) had undergone total knee joint replacement. All were small trials and none was blinded (Jadad score 1-3). PNB technique was variable: in addition to a femoral catheter (n=5), femoral single shot (n=2), or lumbar plexus catheter (n=1) techniques, sciatic blockade was performed in three trials. There was no significant difference in pain scores between epidural and PNB at 0-12 or 12-24 h, WMD 0.22 (95% CI: -0.36, 0.81), 0.05 (-1.01, 0.91), respectively, and no clinically significant difference at 24-48 h, WMD -0.35 (-0.64, -0.02). There was also no difference in morphine consumption (mg) at 0-24 h, WMD -6.25 (-18.35, 5.86). Hypotension occurred more frequently among patients who received epidurals [OR 0.19 (0.08, 0.45)], but there was no difference in the incidence of nausea and vomiting. Two studies reported a higher incidence of urinary retention in the epidural group. Patient satisfaction was higher with PNB in two of three studies which measured this, although rehabilitation indices were similar. PNB with a femoral nerve block provides postoperative analgesia which is comparable with that obtained with an epidural technique but with an improved side-effect profile and is less likely to cause a severe neuraxial complication.     

围手术期目标导向容量治疗用于预防腹部手术后胃肠道并发症的Meta分析

目的 评价围术期目标导向容量治疗对预防腹部手术后胃肠道并发症的有效性,为制定临床合理的个体化容量治疗方案提供理论依据.方法 计算机检索Cochrane图书馆(2010年第3期)、PubMed、EMbase、Highwire、CBM、CNKI等中外生物医学数据库.收集关于围手术期目标导向容量治疗对预防腹部手术后胃肠道并发症方面的临床随机对照试验,检索日期由2000年1月至2010年12月.按Cochrane系统评价方法,评价所纳入研究的文献质量,并提取有效数据后采用RevMan5.0软件进行Meta分析.结果 纳入10项研究,共计775例患者.Meta结果 显示:目标导向容量治疗可显著提高机体氧供(WMD=82.95,95%CI:17.43～148.46),降低胃肠道术后并发症的发生率(RR=0.39,95%CI:0.29～0.52),并缩短住院天数(WMD=-2.06,95%CI:-2.95～-1.17).结论 围手术期目标导向容量治疗可以有效预防术后胃肠道并发症的发生.

Abstract：

Objective To assess whether goal-directed fluid management can prevent gastrointestinal complications in major surgery. Methods Electronic databases including Cochrane library (Issue 3,2010), Pubmed, EMbase, Highwire, CBM, and CNKI were searched. The date of search was between January 2000 and December 2010. Randomized controlled trials (RCTs) were indentified studying association of goal-directed therapy (GDT) with gastrointestinal complications. Study selection and meta-analysis were conducted according to the Cochrane Handbook for systematic reviews. Data were extracted from these trials by 3 reviewers independently and analyzed by RevMan5.0 software. Results Ten trials involving 775 patients were included. GDT significantly improved oxygen supply (WMD=82.95, 95% CI: 17.43-148.46). GDT reduced postoperative hospital stay (WMD=-2.06, 95% CI:-2.95——1.17) and decreased postoperative complication rate after major surgery(RR=0.39, 95% CI: 0.29-0.52). Conclusion Goal-directed fluid management can stabilize cardiac output, augment oxygen supply, and therefore reduce postoperative complications.     

Laparoscopic surgery in a patient with ventriculoperitoneal shunt: monitoring of shunt function with transcranial Doppler

We describe the use of transcranial Doppler (TCD) monitoringduring laparoscopic resection of an ovarian cyst in a youngwoman who previously underwent ventriculoperitoneal shuntingfor hydrocephalus. Shunt function was not altered by pneumoperitoneum,except during transient episodes of high intra-abdominal pressure.The role of TCD monitoring during laparoscopic procedures inpatients with cerebrospinal fluid shunt is discussed. Br J Anaesth 2004; 92: 434–7     

Use of multi-plane transoesophageal echocardiography in visualization of the main hepatic veins and acquisition of Doppler sonography curves. Comparison with the transabdominal approach

The role of multi-plane transoesophageal echocardiography (TOE)in the visualization of the three main hepatic veins and acquisitionof Doppler sonography curves has not been established. We havestudied this diagnostic option of TOE in 34 patients duringgeneral anaesthesia. The findings were compared with the resultsof conventional transabdominal sonography (TAS). Using TOE,each of the three main hepatic veins could be visualized inall patients. In contrast, TAS allowed adequate two-dimensionalvisualization of the right, middle, and left hepatic vein inonly 97%, 85%, and 61% of the patients, respectively. AdequateDoppler tracings of the right and middle hepatic vein couldbe obtained in 100% and 97% of the patients by TOE and in 91%and 50% of the patients by TAS. Doppler tracings of the lefthepatic vein could only be acquired in 18% of the patients byTOE, but in 47% of the patients by TAS. As blood flow may becalculated from the diameter of the vessel, velocity time integralof the Doppler curve and heart rate, TOE may provide an interestingnon-invasive tool to monitor blood flow in the right and middlehepatic vein. Br J Anaesth 2001; 87: 711–7     

Procalcitonin, interleukin 6 and systemic inflammatory response syndrome (SIRS): early markers of postoperative sepsis after major surgery

Background. Patients who undergo major surgery for cancer areat high risk of postoperative sepsis. Early markers of septiccomplications would be useful for diagnosis and therapeuticmanagement in patients with postoperative sepsis. The aim ofthis study was to investigate the association between early(first postoperative day) changes in interleukin 6 (IL-6), procalcitonin(PCT) and C-reactive protein (CRP) serum concentrations andthe occurrence of subsequent septic complications after majorsurgery. Methods. Serial blood samples were collected from 50 consecutivepatients for determination of IL-6, PCT and CRP serum levels.Blood samples were obtained on the morning of surgery and onthe morning of the first postoperative day. Results. Sixteen patients developed septic complications duringthe first five postoperative days (group 1), and 34 patientsdeveloped no septic complications (group 2). On day 1, PCT andIL-6 levels were significantly higher in group 1 (P-values of0.003 and 0.006, respectively) but CRP levels were similar.An IL-6 cut-off point set at 310 pg ml^–1 yielded a sensitivityof 90% and a specificity of 58% to differentiate group 1 patientsfrom group 2 patients. When associated with the occurrence ofSIRS on day 1 these values reached 100% and 79%, respectively.A PCT cut-off point set at 1.1 ng ml^–1 yielded a sensitivityof 81% and a specificity of 72%. When associated with the occurrenceof SIRS on day 1, these values reached 100% and 86%, respectively. Conclusions. PCT and IL-6 appear to be early markers of subsequentpostoperative sepsis in patients undergoing major surgery forcancer. These findings could allow identification of postoperativeseptic complications.     

Immediate extubation and epidural analgesia allow safe management in a high-dependency unit after two-stage oesophagectomy. Results of eight years of experience in a specialized upper gastrointestinal unit in a district general hospital

Background. The perioperative management of two-stage oesophagectomyhas not been standardized and the prevailing practice regardingthe timing of extubation after the procedure varies. This audithas evaluated the outcome, in particular the respiratory morbidityand mortality, after immediate extubation in patients who havehad thoracic epidural analgesia. Methods. All the patients who underwent two-stage oesophagectomyby a single specialist upper gastrointestinal surgeon were recordedboth retrospectively (1993–1999) and prospectively (1999–2001).Physical characteristics, comorbid factors, anaesthetic managementand postoperative events were recorded on a computer database.Analysis was undertaken to evaluate the morbidity and mortality,in particular the need for reventilation and transfer to theITU. Results. Seventy-six patients underwent two-stage oesophagectomybetween 1993 and 2001. Seventy-three (96%) patients were extubatedin theatre and transferred to a high-dependency bed. Three wereventilated electively and extubated within 36 h and madean uncomplicated recovery. Seven (10%) of the immediately extubatedpatients subsequently needed admission to the ICU and reventilation.Sixty-seven patients had effective epidural analgesia and nineneeded i.v. morphine by patient-controlled analgesia. The 30-dayor in-hospital mortality was 2.6% (2 of 76). A further two patientsdied within 90 days, but after discharge. Respiratory complicationswere responsible for half of the overall morbidity (44.7%).Respiratory failure occurred in 6.5% (5 of 76) and acute respiratorydistress syndrome in 2.6% (2 of 76). Both the in-hospital deathsoccurred in patients requiring reventilation and resulted fromrespiratory complications. The following factors were foundto be significant in the reventilated patients: duration ofone-lung ventilation; forced expiratory volume in the firstsecond; and ratio of forced expiratory volume in the first second/forcedvital capacity. Conclusions. Immediate extubation after two-stage oesophagectomyin patients with thoracic epidural analgesia is safe and associatedwith low morbidity and mortality. Patients can be managed ina high-dependency unit, thus avoiding the need for intensivecare. This has cost-saving and logistical implications. Br J Anaesth 2003; 90: 474–9     

Influence of peroperative opioid on postoperative pain after major abdominal surgery: sufentanil TCI versus remifentanil TCI. A randomized, controlled study

Background. Sufentanil and remifentanil are characterized bytwo different pharmacokinetic profiles. The aim of this studywas to compare the effects of sufentanil and remifentanil administeredusing target-controlled infusion (TCI) on recovery and postoperativeanalgesia after major abdominal surgery. Methods. Thirty adult patients scheduled for open colorectalsurgery were included in a prospective, randomized study. SufentanilTCI (sufentanil group) or remifentanil TCI (remifentanil group)was administered during surgery. In the remifentanil group,30 min before the anticipated end of surgery, morphine 0.15mg kg^–1 was administered i.v. In the sufentanil group,an effect-site concentration of 0.25 ng ml^–1 wastargeted at extubation. In both groups, postoperative pain wascontrolled by titration of i.v. morphine and then patient-controlledanalgesia with morphine. Results. The extubation time was similar in the two groups (mean(SD) 13 (6) and 14 (6) min in the sufentanil and remifentanilgroups respectively). Visual analogue scale scores were significantlygreater during the first 2 h after tracheal extubation in theremifentanil group than in the sufentanil group. The time tofirst analgesic request in the postanaesthesia care unit wassignificantly longer in the sufentanil group than in the remifentanilgroup (55 (64) (range 2–240) vs 11 (7) (1–29) min;P<0.001). The cumulative morphine dose for titration wassignificantly greater in the remifentanil group (P<0.01).The cumulative morphine dose used during titration and patient-controlledanalgesia was significantly greater in the remifentanil group4, 12 and 24 h after extubation (P<0.05). Conclusion. TCI sufentanil (0.25 ng ml^–1 effect-siteconcentration at extubation) is more effective than the intraoperativecombination of remifentanil TCI infusion with morphine bolus(0.15 mg kg^–1) for postoperative pain relief aftermajor abdominal surgery and does not compromise extubation andrecovery. Br J Anaesth 2003; 91: 842–9     

Continuous epidural analgesia with bupivacaine-fentanyl versus patient-controlled analgesia with i.v. morphine for postoperative pain relief after knee ligament surgery

BACKGROUND: Both epidural analgesia and intravenous patient-controlled analgesia (PCA) have been found efficacious after various types of surgery. We compared the efficacy, safety, side effects and patient satisfaction of these methods in a randomized double-blind fashion after elective anterior cruciate ligament reconstruction of the knee. METHODS: Fifty-six patients had an epidural catheter placed at the L2-L3 interspace. Spinal anaesthesia with 15 mg of plain bupivacaine 5 mg/ml was performed at the L3-L4 interspace. After surgery the patients were randomly divided into three groups: 19 received a continuous epidural infusion with bupivacaine 1 mg/ml and fentanyl 10 mg/ml (F10), 19 patients received bupivacaine 1 mg/ml and fentanyl 5 microg/ml (F5) and 18 patients received saline (S). The rate of the epidural infusions was 0.1 ml kg(-1) h(-1). Each patient could also use an intravenous (i.v.) PCA device with 40 microg/kg bolus doses of morphine with a lockout period of 10 min and a maximum dose 240 microg kg(-1) h(-1). At the end of surgery ketoprofen 100 mg i.v. was given and continued orally three times a day. Patients were assessed for pain with a visual analogue scale (VAS) at rest and during activity, side effects and satisfaction at 3, 9 and 20 h. RESULTS: Both epidural infusions (F10, F5) provided better analgesia than epidural saline plus i.v. PCA (S) (P<0.05). There was slightly less nausea in the S group (NS). In spite of the difference in the quality of pain relief, there was no difference between the groups in patient satisfaction regarding analgesic therapy. CONCLUSION: Epidural infusion of fentanyl (1 microg kg(-1) h(-1) or 0.5 microg kg(-1) h(-1)) and bupivacaine (0.1 mg kg(-1) h(-1)) provided better pain relief but more side effects than intravenous morphine patient-controlled analgesia after knee ligament surgery. Almost all patients in all groups were satisfied with their pain relief.