Left ventricular pressure-area relations as assessed by transoesophageal echocardiographic automated border detection: comparison with conductance catheter technique in cardiac surgical patients

The aim of this study was to validate measurements of intraoperativeleft ventricular (LV) area by transoesophageal echocardiographyagainst simultaneous measurements of LV volume by conductancecatheter (CC) in cardiac surgical patients with normal systolicLV function. Echo area was compared with CC volume during steadystate and during acute changes of pre- and afterload by partialclamping of the inferior vena cava and the ascending aorta ineight patients scheduled for coronary artery bypass grafting.At steady state, Bland–Altman analysis of 32 recordingsrevealed a bias (SD) of 0.6% (2.5%) between echo area and CCvolume, related to the initial values of end-diastolic area(100% area) and volume (100% volume), respectively. During loadinginterventions, bias between the two methods, as assessed by112 measurement sequences, was 0.5% (3.7%) during aortic occlusionand –3.9% (4.4%) during cava occlusion at end-systole(P<0.0001); at end-diastole, this bias was 1.3% (4%) duringaortic occlusion and 0.2% (5.7%) during cava occlusion (P<0.0001).Intraoperative area measurements with transoesophageal echocardiographyin cardiac surgical patients with normal systolic LV functionshow good correlation with CC volume measurements under steady-stateconditions. During acute unloading by vena cava occlusion, theresulting small end-systolic echo area measurements differ significantlymore from CC volume measurements than during acute increasein afterload by aortic occlusion. Br J Anaesth 2000; 85: 379–88     

Detection of pulmonary hypertension by Doppler echocardiography of the inferior vena cava in chronic airflow obstruction.

Pulsed Doppler echocardiography of the inferior vena cava is an accurate method for the diagnosis of tricuspid regurgitation and impaired right ventricular compliance, two features of pulmonary hypertension. The purpose of this study was to assess the value of Doppler echocardiography of the inferior vena cava for the detection of pulmonary arterial hypertension in patients with chronic obstructive lung disease. Pulse Doppler echocardiography of the inferior vena cava and right heart catheterisation were performed in 29 patients with severe chronic obstructive lung disease. The mean pulmonary arterial pressure was 27 (10) mm Hg for the entire group; 62% of patients (18/29) had pulmonary arterial hypertension (mean pulmonary arterial pressure greater than 20 mm Hg). An adequate Doppler signal could be obtained in 25 of the 29 patients (86%). Pulsed Doppler echocardiography of the inferior vena cava gave normal results in 10 patients and disclosed tricuspid regurgitation in seven patients, impaired right ventricular compliance in seven patients, and both of these abnormalities in one patient. An abnormal Doppler echocardiogram of the inferior vena cava (tricuspid regurgitation or impaired right ventricular compliance, or both) predicted the presence of pulmonary arterial hypertension with a sensitivity of 87% and a specificity of 80%. These results suggest that pulsed Doppler echocardiography of the inferior vena cava may be a useful though imperfect method of detecting pulmonary arterial hypertension in patients with chronic obstructive lung disease.     

Prediction of fluid responsiveness in patients during cardiac surgery

Background. Left ventricular stroke volume variation (SVV) hasbeen shown to be a predictor of fluid responsiveness in varioussubsets of patients. However, the accuracy and reliability ofSVV are unproven in patients ventilated with low tidal volumes. Methods. Fourteen patients were studied immediately after coronaryartery bypass grafting (CABG). All patients were mechanicallyventilated in pressure-controlled mode [tidal volume 7.5 (1.2)ml kg^–1]. In addition to standard haemodynamic monitoring,SVV was assessed by arterial pulse contour analysis. Left ventricularend-diastolic area index (LVEDAI) was determined by transoesophagealechocardiography. A transpulmonary thermodilution techniquewas used for measurement of cardiac index (CI), stroke volumeindex (SVI) and intrathoracic blood volume index (ITBI). Allvariables were assessed before and after a volume shift inducedby tilting the patients from the anti-Trendelenburg (30°head up) to the Trendelenburg position (30° head down). Results. After the change in the Trendelenburg position, SVVdecreased significantly, while CI, SVI, ITBI, LVEDAI, centralvenous pressure (CVP) and pulmonary artery occlusion pressure(PAOP) increased significantly. Changes in SVI were significantlycorrelated to changes in SVV (r=0.70; P<0.0001) and to changesin LVEDAI, ITBI, CVP and PAOP. Only prechallenge values of SVVwere predictive of changes in SVI after change from the anti-Trendelenburgto the Trendelenburg position. Conclusions. In patients after CABG surgery who were ventilatedwith low tidal volumes, SVV enabled prediction of fluid responsivenessand assessment of the haemodynamic effects of volume loading.     

Volumetric preload measurement by thermodilution: a comparison with transoesophageal echocardiography

Background. End-diastolic volume indices determined by transpulmonarythermodilution and pulmonary artery thermodilution may givea better estimate of left ventricular preload than pulmonarycapillary wedge pressure monitoring. The aim of this study wasto compare volume preload monitoring using the two differentthermodilution techniques with left ventricular preload assessmentby transoesophageal echocardiography (TOE). Methods. Twenty patients undergoing elective cardiac surgerywith preserved left–right ventricular function were studiedafter induction of anaesthesia. Conventional haemodynamic variables,global end-diastolic volume index using the pulse contour cardiacoutput (PiCCO) system (GEDVI_PiCCO), continuous end-diastolicvolume index (CEDVI_PAC) measured by a modified pulmonary arterycatheter (PAC), left ventricular end-diastolic area index (LVEDAI)using TOE and stroke volume indices (SVI) were recorded beforeand 20 and 40 min after fluid replacement therapy. Analysisof variance (Bonferroni–Dunn), Bland–Altman analysisand linear regression were performed. Results. GEDVI_PiCCO, CEDVI_PAC, LVEDAI and SVI_PiCCO/PAC increasedsignificantly after fluid load (P<0.05). An increase >10%for GEDVI_PiCCO and LVEDAI was observed in 85% and 90% of thepatients compared with 45% for CEDVI_PAC. Mean bias (2 SD) betweenpercentage changes (     

不同Fontan手术的动物实验对比研究

目的 通过动物实验模似右房－右室连接术、全腔静脉肺动脉连接术及右房－肺动脉吻合术,对比研究３种术式的血流动力学效果及能量损耗情况。方法 选１５只成年杂种犬,随机分成右房－右室连接、全腔静脉肺动脉连接及右房－肺动脉吻合３种,每组５只。右房－右室连接组分别利用５０％及２５％的右室容积参与Ｆｏｎｔａｎ循环。比较三间组的血流动力学参数及能量损耗。结果 与右房－肺动脉连接组相比,无论是５０％还是２５％的右室     

Hemodynamic changes during a new procedure for regional chemotherapy involving occlusion of the thoracic aorta and inferior vena cava

Study Objective: To describe the hemodynamic consequences of a regional chemotherapy procedure involving occlusion of the thoracic aorta and inferior vena cava (IVC) by intraluminal balloons.

Design: Prospective study.

Setting: Operating rooms of an academic hospital.

Patients: 10 patients with inoperable intraabdominal malignancy.

Interventions: After the induction of general anesthesia and the insertion of a pulmonary artery catheter the patients underwent the regional chemotherapy procedure

Measurements and Main Results: Occlusion of the thoracic aorta induced an increase in blood pressure (BP) and systemic vascular resistance (SVR) (41% ± 8% and 80% ± 15% from baseline, respectively), and a 30% ± 7% decrease in cardiac output (CO). After aortic balloon deflation at the end of the procedure, we observed a decrease in BP to baseline values, decrease in SVR (to 62% ± 12% below baseline), and increase in CO (to 80% ± 15% above baseline). Those changes resemble those described during vascular surgery. Isolated occlusion of the IVC before aortic occlusion caused hemodynamic deterioration in only three of 10 patients, suggesting incomplete obstruction or collateral blood flow in others. Occluding the IVC while the aorta was occluded, caused minimal hemodynamic changes.

Conclusions: Independent inflation of the IVC balloon should not be performed routinely because of possible unpredicted hemodynamic instability. Inferior vena cava occlusion should always be performed after complete aortic occlusion, because it is then that it produces negligible hemodynamic consequences. It is possible that a better assessment of IVC occlusion after balloon inflation needs to be done by contrast injection to prevent a possible leak of chemotherapeutic drugs.     

Cardiovascular changes during drainage of pericardial effusion by thoracoscopy

Background. Cardiovascular changes during drainage of pericardialeffusion are not well understood, and most studies are of systemiceffects and not of right ventricular performance. Thoracoscopyis not widely used to drain pericardial effusions because ofhaemodynamic changes in relation to the use of single lung ventilation. Patients and methods. We studied 16 patients undergoing partialpericardiectomy for pericardial effusion, using videothoracoscopywith a low-pressure pneumothorax (6 mm Hg). Cardiac outputwas measured by thermodilution with the patient anaesthetizedin the supine position before the procedure; in the right lateralposition after a low-pressure pneumothorax had been established;and after drainage of the pericardial effusion. Results. Before the procedure, cardiac output was low and centralvenous pressure and pulmonary artery occlusion pressure wereincreased. Systemic vascular resistance and arterial blood pressurewere within normal limits. Cardiac filling pressure and pulmonaryarterial pressure increased during the pneumothorax. After thedrainage cardiac index increased and systemic and pulmonaryvascular resistances were reduced. Conclusions. Pericardial effusion reduces right ventriculardistensibility, right and left systolic ventricular function,and cardiac output. Anaesthesia with mechanical ventilationand a low-pressure pneumothorax do not affect the circulationgreatly. Drainage of the pericardial effusion allows cardiacdistensibility to increase and cardiac performance changes toallow increased ejection. Br J Anaesth 2004; 92: 89–92     

Biventricular repair for right isomerism associated with transposition of great arteries and common atrioventricular canal]

A 5-years old boy, whose thoracic situs was right isomerism, was diagnosed as transposition of great arteries, common atrioventricular canal (intermediate type), severe tricuspid valve regurgitation, pulmonary valve stenosis, bilateral superior vena cava and left sided inferior vena cava. The preoperative RVEDV was 95% and LVEDV 160%, and LV/RV pressure ratio was 0.54. Atrial rerouting using pericardial patch, replacement of tricuspid valve and pulmonary valvotomy were performed. Postoperative course was uneventful. This was a rare case of right isomerism who received biventricular repair.     

Influence of superior vena caval zone condition on cyclic changes in right ventricular outflow during respiratory support.

BACKGROUND: Adequate fluid resuscitation in critically ill patients undergoing mechanical ventilation remains a difficult challenge, and diastolic and systolic right ventricular (RV) changes produced by positive airway pressure are important to consider in an individual patient with inadequate circulatory adaptation during respiratory support. We hypothesized that insufficient thoracic vena cava filling, predisposing to inspiratory collapse (zone 2 condition), may transiently affect RV outflow. METHODS: We measured beat-to-beat superior vena caval diameter and Doppler RV outflow during a routine transesophageal echocardiographic examination in 22 patients undergoing mechanical ventilation, all of whom required hemodynamic monitoring, and we calculated a collapsibility index for the superior vena cava as maximal expiratory diameter minus minimal inspiratory diameter, divided by maximal expiratory diameter. RESULTS: In 15 patients (group 1), the collapsibility index was low (17 +/- 7%) and was associated with a moderate inspiratory decrease in RV outflow (25 +/- 17%). However, in seven patients (group 2), we observed a high collapsibility index (71 +/- 7%), which was associated with a major inspiratory decrease in RV outflow (69 +/- 14%) combined with a reduced pulmonary artery flow period. A rapid volume expansion, only performed on group 2, markedly and significantly reduced both the collapsibility index (15 +/- 12%) and the inspiratory decrease in RV outflow (31 +/- 20%). CONCLUSION: A major inspiratory decrease in RV outflow associated with a reduced pulmonary artery flow period in a patient undergoing mechanical ventilation reflected a high collapsibility index of the thoracic vena cava, suggesting a zone 2 condition, and may be corrected by blood volume expansion.     

Maternal haemodynamics at elective caesarean section: a randomised comparison of oxytocin 5-unit bolus and placebo infusion with oxytocin 5-unit bolus and 30-unit infusion

BackgroundRapid intravenous injection of oxytocin is associated with marked hypotension secondary to decreased venous return. Reductions in dose and rate of bolus administration have reduced the incidence of cardiovascular side effects, but no study has yet investigated cardiovascular stability when oxytocin is infused for several hours after delivery. This study compared maternal haemodynamics during a 4-h 30-unit oxytocin infusion and during a placebo infusion following caesarean section.MethodsWomen booked for elective caesarean section were randomised to receive either oxytocin 5-unit bolus and placebo infusion or oxytocin 5-unit bolus and oxytocin 30-unit infusion. Before, during and for 4 h after surgery electrocardiogram, oxygen saturation, systolic and diastolic pressure and heart rate were monitored non-invasively and cardiac index (CI), left ventricular work index (LVWi) and systemic vascular resistance index (SVRi) by thoracic bioimpedance.ResultsA total of 74 women agreed to haemodynamic measurements. Heart rate, systolic and diastolic pressure, CI, LCWi and SVRi all fell following the onset of spinal anaesthesia, and, with the exception of SVRi, continued to decrease throughout surgery. After delivery of the baby, slow injection of oxytocin 5 units was associated with a temporary rise in CI, LCWi and heart rate, a decrease in SVRi and no change in systolic or diastolic pressure. Thereafter, haemodynamic measures returned to normal over 60 min with no adverse effects apparent from the additional oxytocin infusion.ConclusionsAn additional oxytocin infusion at elective caesarean section did not adversely affect maternal haemodynamics either during or after surgery.     

Inferior and superior vena caval blood flows during cross-clamping of the thoracic aorta in pigs

Changes in blood flow through the inferior and superior venae cavae during cross-clamping of the thoracic aorta just above the diaphragm were studied in 28 miniature pigs anesthetized with enflurane titrated to maintain systemic arterial blood pressure close to normal values. Surgical preparation included sternotomy with subsequent placement of a noncannulating electromagnetic probe around the ascending aorta and a cannulating electromagnetic probe in the transected inferior vena cava. Superior vena caval flow was calculated as the difference between aortic flow and inferior vena caval flow. Clamping of the thoracic aorta alone (n = 10) was accompanied by severe arterial hypertension, a dramatic decrease in inferior vena caval flow, and an increase in superior vena caval flow, which resulted in a moderate increase in aortic flow. Simultaneous clamping of the thoracic aorta and inferior vena cava (n = 13) was accompanied by no significant change in arterial pressure or superior vena caval flow. The oxygen content in mixed venous blood significantly (p less than 0.05) increased from 9.5 +/- 1.1 to 13.4 +/- 1.8 ml.dl-1 in animals undergoing clamping of the thoracic aorta only, but did not change significantly in animals subjected to simultaneous clamping of the aorta and inferior vena cava. The study demonstrates a substantial increase in superior vena caval flow during cross-clamping of the thoracic aorta. Further studies elucidating the mechanism of the observed changes are required.     

Computed tomographic pulmonary angiography and prognostic significance in patients with acute pulmonary embolism

BACKGROUND: Patients with acute pulmonary embolism (APE) present with a broad spectrum of prognoses. Computed tomographic pulmonary angiography (CTPA) has progressively been established as a first line test in the APE diagnostic algorithm, but estimation of short term prognosis by this method remains to be explored. METHODS: Eighty two patients admitted with APE were divided into three groups according to their clinical presentation: pulmonary infarction (n = 21), prominent dyspnoea (n = 29), and circulatory failure (n = 32). CTPA studies included assessment of both pulmonary obstruction index and right heart overload. Haemodynamic evaluation was based on systolic aortic blood pressure, heart rate, and systolic pulmonary arterial pressure obtained non-invasively by echocardiography at the time of diagnosis of pulmonary embolism. RESULTS: The mortality rate was 0%, 13.8% and 25% in the three groups, respectively. Neither the pulmonary obstruction index nor the pulmonary artery pressure could predict patient outcome. In contrast, a significant correlation with mortality was found using the systolic blood pressure (p<0.001) and heart rate (p<0.05), as well as from imaging parameters including right to left ventricle minor axis ratio (p<0.005), proximal superior vena cava diameter (p<0.001), azygos vein diameter (p<0.001), and presence of contrast regurgitation into the inferior vena cava (p = 0.001). Analysis from logistic regression aimed at testing for mortality prediction revealed true reclassification of 89% using radiological variables. CONCLUSION: These results suggest that CTPA quantification of right ventricular strain is an accurate predictor of in-hospital death related to pulmonary embolism.     

Effects of increased intra-abdominal pressure on central circulation

Background. In an experimental model we investigated the effectsof a gradual increase in intra-abdominal pressure (IAP) on thecentral circulation. Methods. Seven pigs were anaesthetized, mechanically ventilatedand instrumented. IAP was gradually increased by 5 mm Hg upto 30 mm Hg by abdominal banding in normovolaemic animals, andthen they were made hypovolaemic after blood withdrawal. Rightatrial pressure (RAP) and left ventricular end-diastolic pressure(LVEDP) at each step and aortic, femoral and inferior vena cavablood flows were measured. Left ventricular end-diastolic area(LVEDA) was determined using epicardial echocardiography. Results. Cardiac output maintained at mild IAP was reduced to76 (24)% of the initial value at 30 mm Hg IAP [mean (SD)] innormovolaemic animals, and 72 (22)% (P<0.001) in hypovolaemicanimals. In normovolaemic animals the LVEDA and LVEDP were significantlyincreased at an IAP of 10 and 15 mm Hg by 26 (24)% and 38 (23)%,respectively. At these IAP values, the difference between theRAP and IAP was positive. When this gradient became negative,that is beyond 15 mm Hg in normovolaemia and for all IAP valuesin hypovolaemic animals, the LVEDA declined, reaching 78 (16)%and 62 (22)% (P<0.05) of the initial values in normovolaemicand hypovolaemic groups at the highest IAP value. Conclusions. These results showed that a gradual increase inIAP led to a redistribution of abdominal blood volume towardsthe thoracic compartment, at IAP lower than 15 mm Hg in normovolaemia,and at its expense at higher values of IAP. In hypovolaemiathere was no thoracic compartment gain. Whereas the absoluteor transmural RAPs were not informative of the direction ofthis blood shift, an RAP greater than IAP was associated withan intrathoracic compartment gain.     

Effects of portal triad clamping on haemodynamic conditions during laparoscopic liver resection

To evaluate the haemodynamic effects of portal triad clamping(PTC) during laparoscopic liver resection, 10 patients withoutcardiac disease were studied by invasive monitoring includinga pulmonary artery catheter and were compared with a controlgroup of 10 patients undergoing liver resection by laparotomy.During laparoscopic surgery, intra-abdominal pressure was keptbelow 14 mm Hg and minute ventilation was adjustedto prevent hypercapnia. Measurements were made before PTC (T1),5 min after PTC (T2) and 5 min after clamp release(T3). During clamping with pneumoperitoneum, mean arterial pressure(MAP) remained stable (+2%; not significant), systemic vascularresistance (SVR) increased by 37% (P<0.01, T2 vs T1) andcardiac index (CI) decreased by 19% (P<0.01, T2 vs T1). Duringlaparotomy and clamping, MAP increased by 18% (P<0.01, T2vs T1), SVR increased by 36% (P<0.01, T2 vs T1) and CI decreasedby 9% (not significant). We were unable to demonstrate a differencein haemodynamic changes during clamping with pneumoperitoneumvs the open surgical technique, but in a small number of patientsthis lack of difference could have been a result of inadequatestatistical power. The haemodynamic changes that we found werewell tolerated in these patients, who had normal cardiac function. Br J Anaesth 2001; 87: 493–6     

HAEMODYNAMIC EFFECTS OF PROPOFOL DURING CORONARY ARTERY BYPASS SURGERY

We have studied the haemodynamic effects of a bolus injectionof propofol 2 mg kg^–1 in 20 patients with good ventricularfunction undergoing aortocoronary bypass surgery. Heart rateand systolic and diastolic systemic (SAP, DAP) and pulmonaryarterial pressures, central venous pressure, pulmonary arterywedge pressure, cardiac output (CO), right ventricular ejectionfraction, systemic (SVR) and pulmonary vascular resistancesand left ventricular stroke work index (LVSWI) were measuredbefore and at 1, 3, 5, 10, 20 and 30min after the administrationof propofol. At 1 min, maximum decreases were detected in SAP(–26%, P < 0.001), DAP (–17%, P<0.001), SVR(–22%, P <0.001) and LVSWI (–23%, P <0.001).The other variables studied showed no significant variationsat any time during the study. We conclude that propofol reducessystemic arterial pressure by a decrease in SVR, but not inCO or ventricular filling pressures. (Br. J. Anaesth. 1993;71: 586–588)     

Influence of Superior Vena Caval Zone Condition on Cyclic Changes in Right Ventricular Outflow during Respiratory Support

Background : Adequate fluid resuscitation in critically ill patients undergoing mechanical ventilation remains a difficult challenge, and diastolic and systolic right ventricular (RV) changes produced by positive airway pressure are important to consider in an individual patient with inadequate circulatory adaptation during respiratory support. We hypothesized that insufficient thoracic vena cava filling, predisposing to inspiratory collapse (zone 2 condition), may transiently affect RV outflow.

Methods : We measured beat-to-beat superior vena caval diameter and Doppler RV outflow during a routine transesophageal echocardiographic examination in 22 patients undergoing mechanical ventilation, all of whom required hemodynamic monitoring, and we calculated a collapsibility index for the superior vena cava as maximal expiratory diameter minus minimal inspiratory diameter, divided by maximal expiratory diameter.

Results : In 15 patients (group 1), the collapsibility index was low (17 +/- 7%) and was associated with a moderate inspiratory decrease in RV outflow (25 +/- 17%). However, in seven patients (group 2), we observed a high collapsibility index (71 +/- 7%), which was associated with a major inspiratory decrease in RV outflow (69 +/- 14%) combined with a reduced pulmonary artery flow period. A rapid volume expansion, only performed on group 2, markedly and significantly reduced both the collapsibility index (15 +/- 12%) and the inspiratory decrease in RV outflow (31 +/- 20%).     

Hemodynamic Studies in Long-Term Peritoneal Dialysis Patients

A study was undertaken to evaluate the acute hemodynamic effects in ten patients from this clinic's long-term peritoneal dialysis program. With a Swan-Ganz catheter, the following parameters were measured in each patient during peritoneal dialysis: cardiac index, pulmonary artery pressure, right atrial pressure, inferior vena cava pressure, heart rate and arterial pressure. Mean predialysis cardiac index, stroke volume index and heart rate were normal. Predialysis pulmonary artery pressure and arterial pressure were slightly elevated. Mean weight loss during peritoneal dialysis was 1.6 kg. The most striking post-dialysis changes were a significant 20% decrease of the cardiac index and a 17% decrease of the pulmonary artery pressure. Heart rate and arterial pressure remained constant due to a 25% increase of total peripheral resistance. After filling the abdomen with one, two and three liters of dialysate, intra-abdominal pressure and inferior vena cava pressure increased up to 150 and 100%, respectively, whereas central hemodynamic parameters (pulmonary artery pressure, cardiac index, stroke volume index, heart rate and arterial pressure) were unchanged.     

Effect of thoracic epidural anaesthesia on colonic blood flow

Background. The effect of thoracic epidural block on splanchnicblood flow is unclear. It remains to be resolved if sympatheticblock, increases or decreases regional splanchnic blood flowand whether regional splanchnic flow becomes dependent on cardiacoutput or perfusion pressure. A clear understanding of the regionalhaemodynamic consequences of an epidural block may modify practicewith respect to epidural anaesthesia. Methods. Fifteen patients, who underwent anterior resectionfor rectal cancer, had invasive intraoperative monitoring ofarterial pressure, central venous pressure, cardiac output,inferior mesenteric artery flow (Doppler flow probe), and colonicserosal red cell flux (laser Doppler probe), while an epiduralblock was established with local anaesthetic. In three consecutivetime periods, arterial pressure was first allowed to fall (toa mean arterial pressure of 60 mm Hg), then treated with colloidfluid resuscitation and finally by vasopressors until the pre-epidural arterial pressure had been restored. Results. On induction of epidural block, there was a reductionin mean colonic serosal red cell flux to 65% and inferior mesentericartery flow to 80% (mean) of pre-epidural levels. There wasa strong association between mean arterial pressure and bothmeasured inferior mesenteric artery blood flow (P<0.004)and colonic serosal red cell flux (P<0.0001). Changes incardiac output were poorly associated with either inferior mesentericartery blood flow (P=0.638) or colonic serosal red cell flux(P=0.265). Inferior mesenteric artery blood flow and colonicserosal red cell flux were restored to pre-epidural levels afterarterial pressure had been improved with a vasopressor. Conclusion. Once intraoperative epidural block has been established,colonic serosal red cell flux and inferior mesenteric arteryflow are more closely associated with changes in mean arterialpressure than changes in cardiac output. The measured reductionin colonic flow does not respond to an increase in cardiac outputwith fluid resuscitation, but requires the use of a vasopressorto increase arterial pressure, before colonic blood flow isimproved. Br J Anaesth 2002; 89: 446–51     

Intra-atrial ECG is not a reliable method for positioning left internal jugular vein catheters

Background. ECG guidance is widely used for positioning centralvenous catheters (CVCs) in the superior vena cava. We noticeda higher incidence of a more perpendicular angle between thecatheter tip and the vessel wall after left-sided ECG-guidedcatheter positioning. To investigate the value of left-sidedECG guidance, we performed this prospective study. Methods. Of 114 patients, 53 were randomized to right and 61to left internal jugular vein catheterization using a triplelumen catheter. Three methods to ascertain catheter tip positionwere sequentially applied in each patient, and the insertiondepths (ID) obtained using each of the three methods were recorded:(i) ECG guidance with a Seldinger guide wire (ID-A); (ii) ECGguidance with saline 10% used as an exploring electrode (ID-B);(iii) from position ID-B, the catheter was rotated and advanceduntil all three lumina could be aspirated easily. The catheterwas fixed in that position (ID-C). To determine final cathetertip position, intraoperative transoesophageal echocardiography(TOE) and a postoperative chest X-ray (CXR) were performed. Results. The depth of insertion of a catheter using the threemethods varied significantly in left-sided (P<0.001), butnot in right-sided catheters. Forty-eight of 57 (84%) left-sidedCVCs, correctly positioned according to ECG guidance, had tobe advanced further to achieve free aspiration through all threelumina. By this stage, five of the catheter tips had been positionedin the upper right atrium as demonstrated by TOE. There were13 malpositions (23%) after left-sided insertion. In nine cathetermalpositions, undetected by ECG guidance, the angle betweenthe catheter tip and the lateral wall of the superior vena cavaexceeded 40° on CXR. Conclusions. Intra-atrial ECG does not detect the junction betweenthe superior vena cava and right atrium. It is not a reliablemethod for confirming position of left-sided CVCs. Post-proceduralCXRs are recommended for left-sided, but not right-sided CVCs. Br J Anaesth 2003; 91: 481–6     

Pneumonectomy in scimitar syndrome —is it correct?

The scimitar syndrome is a rare congenital anomaly that is characterized by anomalous pulmonary venous drainage to the inferior vena cava causing a left-to-right shunt. Because the radiographic shadow of the anomalous vein resembles a curved turkish saber, this defect has been called as the “scimitar deformity”¹. Here we present a two months old male child with an anomalous drainage of the single right pulmonary vein draining the entire right lung into the inferior vena cava, direct arterial supply from the abdominal aorta to the right lung, horse-shoe lung and unilobar hypoplastic right lung. The child was treated surgically with a right pneumonectomy. The child had an uneventful postoperative recovery.