The Influence of the Univent® Endotracheal Tube on Internal Jugular Vein Cannulation

This prospective clinical investigation assessed the effect of placement of a Univent® tube on the anatomy of the internal jugular veins and the success of cannulation of the left internal jugular vein. After obtaining informed consent, 48 adult patients were enrolled. Of these, 42 patients were eligible and were divided into two groups: Univent® tube (group U, n=21) and wire enforced endotracheal tube (group C, n=21). The Univent® tube group were having a left thoracotomy. Using horizontal ultrasound scans just above the thyroid gland, the internal jugular vein was visualized and measured before and after Univent® placement. The number of needle passes necessary to cannulate the left internal jugular vein in the two groups was also compared.

Univent® tubes were associated with lateral displacement of the right carotid artery and internal jugular vein on the convex side of the Univent® tube, with compression of the right internal jugular vein by the artery, resulting in a kidney-shaped cross-section of the vein. On the left (concave side of the tube), the neck was indented, the sheath of the left carotid artery was displaced medially, and the left internal jugular vein distorted to an ellipse. There was a significant increase in the lateral diameter and a decrease in the cross-sectional area of the left internal jugular vein (t-test, P<0.05). The first attempt at cannulation of the left internal jugular vein failed significantly more often in the Univent® group (13/21 vs 5/21 in group C, Chi-square 6.22, P=0.025). Cannulation of the internal jugular vein before placement of the Univent® tube, or placement with ultrasound guidance is suggested.

[Sepsis masquerading as delirium]

A previously healthy 60-year-old patient presented to the emergency department with severe headache, altered personality and fever. He was treated for bacterial meningitis with delirium of unknown cause but presumed to be due to alcohol withdrawal. Despite receiving the antibiotic therapy regimen recommended for bacterial meningitis the patient's condition rapidly deteriorated with profound delirium and tachypnea. The intensivist who was consulted immediately suspected sepsis-associated organ failure and admitted the patient to the intensive care unit (ICU). The blood culture was positive for Listeria. After 10 days the patient could be discharged from the ICU and ultimately recovered completely. In patients presenting with unexplained delirium or altered personality the suspicion of septic encephalopathy should always be considered. They should be admitted to the ICU and sepsis treatment should be initiated without delay.

[Cardiac herniation and torsion after transpericardial pneumonectomy]

This article presents the case of a 43 year old woman with right-sided lung cancer. She underwent transpericardial pneumonectomy. After an uneventfull surgery, the patient was transferred to the intensive care unit for postoperative monitoring. She was hemodynamically stable and had already been extubated in the OR.On postoperative chest X‑ray a mediastinal shift to the operated side as well as a herniation of the heart into the right chest cavity was detected. While the patient remained hemodynamically stable a computed tomography of the chest was performed which confirmed the diagnosis of cardiac herniation and torsion. The lady underwent rethoracotomy the following day where the heart was repositioned and the pericardial defect was closed. She made an uneventfull recovery.Five years after the pneumonectomy she remains well and is without relapse of lung cancer.Mechanism for cardiac herniation and torsion, the clinical presentation and the typical radiologic signs are discussed. However, the clue to early diagnosis is a high index of clinical suspicion.It is highlighted that a hemodynamically unstable patient under these circumstances demands urgent rethoracotomy.

Pre-procedure ultrasound increases the success and safety of central venous catheterization†

BACKGROUND

Real-time ultrasound (US) in central venous catheterization is superior to pre-procedure US. However, moving real-time US into routine practice is impeded by its perceived expense and difficulty. Currently, pre-procedure US and landmark (LM) methods are most widely used. We investigated these techniques in internal jugular vein (IJV) catheterization in respect of operator experience, complications, and risk factors.

METHODS

In an observational non-randomized study, we investigated 606 of ∼1300 procedures, that is, 200 patients were treated under pre-procedure US and 406 under LM [pathfinder (PF) n=202, direct cannulation (DC) n=204]. We recorded first needle pass success rate, success rate after the third attempt, and the cannulation time. Procedures were performed by inexperienced (<100) or experienced (>100 catheterizations) operators.

RESULTS

Pre-procedure US was associated with more successful attempts and shorter cannulation times. Under pre-procedure US, 88% of first attempts were successful and 100% of third attempts. The median (range) cannulation time was 39 (10-330) s. Under PF, only 56% of first, and 87% of third, attempts were successful with a median (range) cannulation time of 100 (25-3600) s. Under DC, 61% of first and 89% of third attempts were successful; the median (range) cannulation time was 70 (10-3600) s. Remarkably, inexperienced operators using pre-procedure US (n=38) were significantly faster than experienced operators using PF or DC (n=343) (cannulation time: median 60 s, range 12-330, for inexperienced; 60 s, range 10-3600, for experienced). First puncture success rates were higher (pre-procedure US, inexperienced 84%, PF or DC, experienced 57%).

CONCLUSIONS

Pre-procedure US for IJV catheterization is safe, quick, and superior to LM.

Bone cement embolism attached to central venous catheter

We report on a rare complication of poly(methyl methacrylate) (PMMA), injected into the spine, which then inadvertently leaked into the venous system. This resulted in an embolism of PMMA and produced a mass surrounding a triple lumen central venous catheter located in the superior vena cava. The catheter as well as the attached mass of PMMA was retrieved safely by cardiothoracic surgery. This case emphasizes the importance of prompt diagnosis and treatment and illustrates the need for close monitoring of patients undergoing any spinal surgery that includes vertebroplasty.

Influence of systolic-pressure-variation-guided intraoperative fluid management on organ function and oxygen transport

BACKGROUND

Dynamic variables, for example, systolic pressure variation (SPV), are superior to filling pressures for assessing fluid responsiveness. We analysed the effects of SPV-guided intraoperative fluid management on organ function and perfusion when compared with routine care.

METHODS

Eighty patients (44 female and 36 male) undergoing elective major abdominal surgery were randomly assigned to a control group [n=40, mean age 66 (sd 10), range 40-84 yr] or SPV group [n=40, age 61 (16), range 26-100 yr] in which intraoperative fluid management was guided by SPV (trigger: SPV>10%). Central venous O2 saturation (ScvO2), lactate and bilirubin, creatinine, indocyanine green plasma disappearance rate (ICG-PDR), and gastric mucosal CO(2) tension were measured after induction of anaesthesia, after 3, 6, 12, and 24 h.

RESULTS

Patient characteristics, duration of surgery [5.8 (2.5) vs 5.4 (2.5) h], and infusion volumes (median 4865 vs 4330 ml) were comparable between the groups. At 3 and 6 h, SPV (P=0.04, P=0.01) and Deltadown (P=0.005, P=0.01) were significantly higher in the control group. Oxygen transport and organ function were comparable: baseline and 24 h values for ICG-PDR: 28.5 (7.9) and 22.7 (7.8) vs 23.9 (6.9) and 26.1 (5.9)% min(-1), 77.7 (6.6) and 72.6 (5.5) vs 79.3 (7.1) and 72.8 (6.7)% for ScvO2 and 1.0 (0.4) and 1.2 (0.6) vs 0.9 (0.2) and 1.3 (0.5) mmol litre(-1) for lactate. Length of mechanical ventilation, ICU stay, and mortality were comparable.

CONCLUSIONS

In comparison with routine care, intraoperative SPV-guided treatment was associated with slightly increased fluid adminstration whereas organ perfusion and function was similar.

Detection of tracheal malpositioning of nasogastric tubes using endotracheal cuff pressure measurement

BACKGROUND

Insertion of a gastric tube (GT) in anaesthetized, paralyzed and intubated patients may be difficult. Tracheobronchial malposition of a GT may result in deleterious consequences. The purpose of this study was to determine the reliability of tracheal cuff pressure measurement to detect endobronchial malposition of GTs. We compared this new method with the measurement of exhaled CO(2) through the GT.

METHODS

Thirty patients under general anesthesia and orotracheal intubation were analysed. First, the cuff pressure of the low-volume endotracheal tube (ET; ID 7.0-8.5 mm) was increased to 40 cmH(2)O. Then, in a randomized fashion, the GT (18 Charrière) was inserted consecutively into the trachea and oesophagus or vice versa. Cuff pressure was monitored continuously while advancing the GT. Furthermore, a capnograph was connected to the gastric tube and the aspirated PCO(2) was monitored.

RESULTS

Advancement of the gastric tube into the oesophagus increased ET cuff pressure by 1 +/- 1 cmH(2)O, while endotracheal placement of the GT increased cuff pressure by 28 +/- 8 cmH(2)O (P < 0.001). Using an increase of >10 cmH(2)O in cuff pressure detected endotracheal malpositioning of the GT with 100% sensitivity and specificity. In 28 out of 30 cases, PCO(2) increased by more than 2.6 kPa. Thus, the PCO(2) approach failed to detect tracheal malpositioning in two cases resulting in a sensitivity of 93.3%.

CONCLUSIONS

In intubated patients, cuff pressure measurement during insertion of a gastric tube is a new, simple and reliable bedside method to detect endotracheal malpositioning of a GT.

[Tracheal agenesis. A rare cause of respiratory insufficiency in neonates]

Tracheal agenesis is a very rare congenital anomaly that occurs isolated or in combination with other anomalies. It presents immediately after birth with an absolute respiratory insufficiency and lack of crying. The immediate precise anatomical classification of the anomaly is crucial in order to decide if surgical therapy is possible. This report describes a newborn boy with tracheal agenesis type II. The diagnosis was confirmed by spiral computed tomography and a selection of the pictures is presented. The treatment was discontinued due to a lack of therapeutical options. Based on this case report we discuss the special situation of this rare anomaly. Interesting information on tracheal agenesis was gathered, the differential diagnosis of respiratory insufficiency of the newborn is summarised and a modified algorithm of the current newborn resuscitation guidelines of the American Heart Association is presented.

Optimierte Positionierung zentraler Venenkatheter durch eine modifizierte Anwendung der intravasalen Elektrokardiographie

BACKGROUND

Intraatrial electrocardiography (ECG) is a well-established method for central-venous catheter (CVC) placement and an intraatrial position is assumed, when a significantly increased P-wave is registered. However, an increase in P-wave amplitude also occurs in other positions. Therefore we evaluated CVC tip positioning by means of transesophageal echocardiography (TEE) at a maximum P-wave amplitude.

PATIENTS AND METHODS

In this prospective randomized study the right or left internal jugular vein was cannulated with 100 patients in each group and catheter tip positioning was guided by means of ECG. The catheter was fixed at the position of maximum P-wave amplitude and the insertion depth was registered. The relationship of the CVC tip position to the superior edge of the crista terminalis was demonstrated with the help of TEE.

RESULTS

In all patients the catheter tip was found +/- 0.5 cm from the superior edge of the crista terminalis at the transition from the superior vena cava to the right atrium. On x-ray control, all catheters ran along the length of the vessel wall of the superior vena cava.

CONCLUSIONS

A maximum P-wave is derived even at the entrance to the right atrium. This explains why ECG-guided CVC placement -- based on the largest P-wave amplitude -- consistently resulted in correct positioning of the CVC tip at the transition from the superior vena cava to the right atrium.

ECG recording of central venous catheter misplaced in inferior thyroid artery

A 71-year-old male patient with liver metastases secondary to rectal carcinoma was scheduled for hemi-hepatectomy. Two months earlier he had undergone subtotal resection of the thyroid gland. Prior to surgery, a triple-lumen catheter and an introducer sheath were introduced into the right internal jugular vein using a landmark technique. No problems occurred during insertion of the triple-lumen catheter, but resistance was noticed during insertion of the 8.5 FG introducer sheath. After placement of the introducer sheath, intra-arterial misplacement was confirmed using a pressure transducer. The opportunity was taken to record and compare intravascular ECG by the arterial and venous catheters before removal. No difference was noticed in the P-wave patterns; both showed a marked increase. Surgical exploration of the neck, recommended by the vascular surgeon consulted, showed that the carotid artery was not injured. The introducer sheath had completely punctured the right internal jugular vein and entered the inferior thyroid artery. A thrill was felt. The management of this case is discussed, with suggestions for best practice. Intravascular ECG was unhelpful in differentiating between venous and arterial placement of the catheter.

Extravasale Lage von zentralen Venenkathetern bei korrekter EKG-Ableitung

OBJECTIVE

Does the electrocardiographic method for central venous catheter positioning distinguish between a correct intravasal and a malpositioned extravasal position?

METHODS

24 cardiac surgical patients were enrolled in this prospective observational study. In 18 patients the left, in another 6 patients the right internal jugular vein was cannulated. Using a J-wire within a triple-lumen catheter the amplitude of the P-wave was measured at 3 different intravasal sites: Intra-1: (intravasal baseline electrocardiogram), i. e. 10 cm marking of the catheter on skin level; Intra-2: clear rise of the P-wave amplitude upon further insertion of the catheter; Intra-3: maximum P-wave amplitude. At this position the control of the catheter tip was achieved by means of transoesophageal echocardiography (TOE). Intraoperatively, another J-wire within a triple-lumen catheter was placed by the heart surgeon on 3 extravasal sites and the ECG was recorded: Extra-1: extravasal at the left innominate vein above the pericardial reflection; Extra-2: extravasal on the superior vena cava below the pericardial reflection; Extra-A: extravasal on ascending aorta below the pericardial reflection. The catheter was suture fixed with its tip in position Intra-3. Post surgery a chest radiograph was taken.

RESULTS

All catheter tips were visualised at the basis of the Crista terminals (border between right atrium and superior vena cava) by TOE control. The rise of the P wave amplitude at Intra-2, Extra-2 and Extra-A was highly significant compared to the base line at Intra-1 (Intra-1/Intra-2, Intra-1/Extra-2, Intra-1/Extra-A: p in each case < 0.001). The P wave amplitudes of the corresponding intra- and extravasal positions of the left innominate vein (Intra-1/Extra-1, n = 18, p = 0.096)) as well as those of the superior vena cava (Intra-2/Extra-2, n = 24, p = 0.859) did not differ.

CONCLUSION

The electrocardiographic method can not differentiate between intra- and extravasal position of a central venous catheter, and thus, presumably fails to identify malpositioning as a result of vascular perforation.

[Uncorrected transposition of the great arteries and large ventricular septum defect perioperative management of a caesarean section]

Patients with congenital cyanotic heart disease are a challenge to the anaesthetist due to the individual haemodynamic characteristics. Maintaining a balance between systemic and pulmonary-vascular resistance is crucial. Here we outline the successful perioperative management of a 24-year-old female with uncorrected transposition of the great arteries (D-TGA) and large septal defect of the ventricle (functionally single ventricle). She was transferred to our perinatologic centre in the 32nd week of pregnancy with symptoms of increasing cardial insufficiency. The peripartum management was agreed upon at an interdisciplinary conference and caesarean section was performed in the 35th week of pregnancy with epidural anaesthesia and no significant problems. Due to hypercoagulability and the risk of "paradoxical" embolism, low molecular weight heparin was given for 6 weeks post partum. The infant was underweight and was admitted to the neonatal intensive care unit, where she made a satisfactory progress.

ECG-guided central venous catheter positioning: does it detect the pericardial reflection rather than the right atrium?

BACKGROUND AND OBJECTIVE

Although electrocardiography (ECG) guidance of central venous catheters (CVCs) is traditionally thought to detect the entrance into the right atrium (RA), there is little evidence in the literature to confirm this. We previously observed a high incidence of left-sided CVCs abutting the wall of the superior vena cava (SVC), even when the catheters were advanced past the point of increased P-wave amplitude. Our hypothesis was that this ECG amplitude signal is actually detecting the pericardial reflection rather than the RA. The goal of the study was to position catheter tips under ECG guidance outside the RA.

METHODS

One-hundred central venous triple-lumen catheters inserted either via the right or the left internal jugular veins, respectively, were analysed in cardiac surgical patients. The position of the catheter tip was ascertained by ECG. METHOD A: A Seldinger guide-wire in the distal lumen served as exploring electrode, the respective insertion depth was recorded. METHOD B: The middle lumen (port opening 2.5 cm from the catheter tip, thus the catheter was advanced more towards the atrium) filled with a saline 10% fluid column served as the exploring electrode, and the insertion depth was recorded again. Descriptive data are given as mean+/-standard deviation.

RESULTS

On average, the catheters were advanced by the expected 2+/-0.3 cm using Method B beyond the initial insertion by Method A. All 100 CVCs were finally correctly positioned in the SVC and confirmed by transoesophageal echocardiography. When chest radiography was performed after surgery not a single catheter abutted the lateral wall of the SVC.

CONCLUSION

Since both methods detected the same structure, and catheters placed by Method B did not result in intra-atrial CVC tip position, the first increase in P-wave amplitude does correspond to a structure in the SVC, most likely the pericardial reflection.

Central venous catheters—the inability of ‘intra-atrial ECG’ to prove adequate positioning

BACKGROUND

The classic increase in P wave size, known as 'P-atriale', is a widely accepted criterion for determination of proper positioning of central venous catheter tips. Recent transoesophageal echocardiography (TOE) studies did not confirm intra-atrial position despite advancing the central venous catheter further than indicated by ECG guidance. We postulate that the pericardial reflection rather than the entry into the right atrium corresponds to the ECG changes. In order to test our hypothesis we sought to determine the anatomical substrate for the electrical changes in an animal study. Subsequently, a modified version of the study was undertaken in man and is also reported.

METHODS

In six juvenile pigs the left external jugular vein and right carotid artery were cannulated. A triple-lumen central venous catheter was positioned by ECG guidance using a Seldinger wire as an exploring electrode. The venous and arterial catheters were suture fixed 2 cm beyond the onset of an increase in P wave size. The corresponding anatomical catheter tip position was determined by open exploration of the vessels and the heart. Subsequently the catheter tip position (during advancement) of a pulmonary artery catheter and the corresponding electrical ECG changes were examined in 10 patients during open chest cardiac surgery.

RESULTS

All catheters-arterial and venous, in animals and humans-revealed an increase in size of the P wave as well as the QRS complex. All venous catheters were positioned in the superior vena cava, beyond the pericardial reflection but outside the right atrium. All arterial catheters were positioned in the ascending aorta thus also beyond the pericardial reflection.

CONCLUSIONS

The start of an increase in P wave size does not correspond with the entrance of the right atrium. The anatomic equivalent for the electrophysiological changes of the ECG is the pericardial reflection. ECG guidance is unable to distinguish between venous and arterial catheter position.

Verzögertes Einsetzen einer Malignen Hyperthermie während einer Leberlebendspende unter Sevoflurananästhesie

We report on a 25-year old ASA physical status I patient, who developed within 20 minutes a full-blown malignant hyperthermia (MH) in the context of a living donor liver transplantation after 180 minutes of uneventful anaesthesia. The only trigger substance applied was Sevoflurane. The patient had already received a short, uneventful anaesthesia with Isoflurane a couple of years ago. In the context of the special constellation an initial dose of Dantrolene of 10 mg/kg body weight was administered. The patient was stabilised within 30 minutes, and the enzyme levels remained low compared with other case reports. The post-operative in vitro caffeine halothane contracture testing confirmed that son and mother were susceptible to MH, contracture testing in the father was negative. All known triggers may cause life-threatening MH crisis - even after hours and after inconspicuous multiple exposures to known trigger substances. Therefore all trigger substances must be avoided in all patients susceptible to MH.

Zur Anwendung von Ultraschall bei der Anlage zentraler Venenkatheter in Deutschland: Eine Umfrage unter 817 Anästhesieabteilungen

OBJECTIVE AND METHODS

A survey on the current practice in using portable ultrasound machines to assist central vein cannulation was performed by sending a questionnaire to 817 departments of anaesthesiology and intensive care medicine in Germany. Also, incomplete questionnaires were included in the analysis.

RESULTS

There was a 54 % response rate. Ultrasound guidance is used by 83 (18.7 %) departments for central vein cannulation. Of these, only 7 (8.4 %) use it routinely and 43 (51.8 %) use it when faced with a difficult vein cannulation. Only one third of the departments with ultrasound facilities are using it optimally, e. g. cannulation under ultrasound guidance. Of those units not using ultrasound for central vein cannulation, 136 (37.7 %) said it was because of lack of equipment and 199 (55.1 %) did not think that it was necessary.

CONCLUSION

In Germany, placement of central venous catheters is usually based on anatomical landmarks. Every anaesthetist and intensive care physician should be able to place central venous catheters without an ultrasound device. Still there is not a doubt that ultrasound assistance is useful for beginners, in children, and when blind cannulation fails. Also in patients in whom catheterisation is likely to be difficult (e. g. patients, with previous central venous catheters, with abnormal anatomy etc.) Due to our data a promotion of ultrasound assistance seems urgently required.

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

BACKGROUND

ECG guidance is widely used for positioning central venous catheters (CVCs) in the superior vena cava. We noticed a higher incidence of a more perpendicular angle between the catheter tip and the vessel wall after left-sided ECG-guided catheter positioning. To investigate the value of left-sided ECG guidance, we performed this prospective study.

METHODS

Of 114 patients, 53 were randomized to right and 61 to left internal jugular vein catheterization using a triple lumen catheter. Three methods to ascertain catheter tip position were sequentially applied in each patient, and the insertion depths (ID) obtained using each of the three methods were recorded: (i). ECG guidance with a Seldinger guide wire (ID-A); (ii). ECG guidance with saline 10% used as an exploring electrode (ID-B); (iii). from position ID-B, the catheter was rotated and advanced until all three lumina could be aspirated easily. The catheter was fixed in that position (ID-C). To determine final catheter tip position, intraoperative transoesophageal echocardiography (TOE) and a postoperative chest X-ray (CXR) were performed.

RESULTS

The depth of insertion of a catheter using the three methods varied significantly in left-sided (P<0.001), but not in right-sided catheters. Forty-eight of 57 (84%) left-sided CVCs, correctly positioned according to ECG guidance, had to be advanced further to achieve free aspiration through all three lumina. By this stage, five of the catheter tips had been positioned in the upper right atrium as demonstrated by TOE. There were 13 malpositions (23%) after left-sided insertion. In nine catheter malpositions, undetected by ECG guidance, the angle between the catheter tip and the lateral wall of the superior vena cava exceeded 40 degrees on CXR.

CONCLUSIONS

Intra-atrial ECG does not detect the junction between the superior vena cava and right atrium. It is not a reliable method for confirming position of left-sided CVCs. Post-procedural CXRs are recommended for left-sided, but not right-sided CVCs.

[Pseudoaneurysm--a rare complication of internal jugular vein cannulation: two case reports in liver transplant patients]

Internal jugular vein catheterization is nowadays a routine procedure in clinical practice. Arterial puncture is the most common complication of internal jugular vein catheterization. Two cases of pseudoaneurysm formation as a complication of accidental arterial puncture in liver transplant patients with coagulopathy are presented. Punctures of the common carotid artery, thyrocervical trunk, respectively were the source for these lesions. Coagulopathy is seen as an essential factor in the formation of pseudoaneurysm. Especially in patients with coagulopathy the threshold for ultrasound guidance should be low. Under these circumstances using the external jugular vein seems to be more prudent as it eliminates the risk for arterial punctures. We illuminate the genesis, signs and symptoms, diagnosis, and therapy of pseudoaneurysm. Recommendations for risk reduction are given.

[Extravasation: a rare complication of central venous cannulation? Case report of an imminent erosion of the common carotid artery]

Extravasation is the non-intentional leakage of substances/solutions into the perivascular or subcutaneous space that can result in significant tissue damage. The extent of destruction depends on the properties of the substance, its concentration, and the amount applied. Substances known to cause severe tissue damage include certain chemotherapeutic agents, vasoactive substances, concentrated electrolytes, and other hyperosmolar solutions. Extravasation can be avoided by meticulous monitoring of venous access. When extravasation occurs, the infusion should be stopped immediately. Substances known to cause tissue damage should be removed from perivascular or subcutaneous space within 24 hours by local incision and irrigation. A delay in early treatment may necessitate more extensive surgical debridement and skin coverage operations. Since the extent of deep soft tissue damage is difficult to predict and is often underestimated, a magnetic resonance imaging should be performed before surgery. We report here on a 73-year-old patient, in whom extravasation of potassium-chloride from a dislocated multi-lumen central venous catheter led to a life-threatening skin and soft-tissue necrosis of the neck. This article provides an overview of common vesicants, theories of tissue destruction, potential risk factors, guidelines for prevention, and current treatment strategies.

Chylothorax nach Anlage eines zentralvenösen Katheters

The authors report on a chylothorax, a rare, although classical complication of left internal jugular vein cannulation. The anatomy of major lymphatic vessels including variations is illustrated. The mechanisms of central venous catheter associated chylothorax are discussed. Likewise described are pathophysiology, signs, clinical features, and differential diagnosis with special consideration of the triglyceride content as well as treatment options.

Persistent left superior vena cava and central venous catheter position: clinical impact illustrated by four cases

Variations in the course of the blood vessels are often incidental findings during clinical examination. A persistent left superior vena cava (LSVC) is really not rare (healthy individuals, 0.3-0.5%; patients with congenital heart disease, 4%) and serious complications have been described during catheterization in adults with LSVC (shock, cardiac arrest, angina). Therefore variations of the superior vena cava should be considered, especially when central venous catheterization via the subclavian or internal jugular vein is difficult. We describe the embryogenesis and the anatomic variations of persistent LSVC. Subsequently we suggest a classification of superior vena cava according to the positioning of a central venous catheter on the chest radiograph: type I, normal anatomy; type II, only persistent left superior vena cava; type IIIa, right and left superior vena cava with connection; type IIIb, right and left superior vena cava without connection. This classification is illustrated by four clinical cases.

[Differential diagnosis of left-sided thoracic venous catheters: case report of a persistent left superior vena cava]

The differential diagnosis of left-sided thoracic central venous catheters is discussed in context with the cannulation of a persistent left superior vena cava. In this case the catheter tip was seen lying to the left of the spine on frontal chest X-ray. In addition to the descending aorta, differential diagnoses are a persistent left-sided superior vena cava as well as other smaller veins such as the left internal thoracic vein, the left superior intercostal vein, or the pericardiophrenic vein. The misplacement of a venous catheter in a pericardiophrenic vein may result in a fatal pericardial tamponade.

Loss of the guide wire: mishap or blunder?

We describe four cases of lost guide wires during central venous catheterization. Although percutaneous catheterization of central veins is a routine technique, it is a procedure requiring advanced operating skills, expert supervision, and attention to detail in order to prevent adverse effects.

[Perforation of the superior vena cava due to unrecognized stenosis. Case report of a lethal complication of central venous catheterization]

We report on a case of fatal perforation of the superior vena cava. The perforation occurred after catheterization of the left internal jugular vein with a hemodialysis catheter, due to an unrecognised stenosis of the superior vena cava. Vascular trauma induced by a previous, also left-sided, subclavian vein-hemodialysis catheter (in place for 14 days), seemed to be the most likely pathomechanism of the stenotic lesion. It should be emphasised that this is a frequent complication especially of left-sided dialysis catheters. In the case described a stenosis was complicated by a misdirected second hemodialysis catheter. Although being repositioned under fluoroscopic control via a guide wire, an extravasal placement occurred but was unrecognised. In order to rule out catheter misplacement, the position of every central venous catheter has to be controlled. Standard methods are either chest X-ray or right atrial electrocardiography. Additionally, confirmation of correct intravenous placement requires a combination of free venous backflow of all lumen and/or blood gas analysis or venous pressure monitoring. Only a combination of tests gives ample certainty as each test for itself has its pitfalls. After placement of hemodialysis catheters, in particular left-sided catheters, we demand chest X-ray in order to verify that the catheter runs parallel with the long axis of the superior vena cava. In doubtful cases the threshold for contrast-enhanced angiographic control of the catheter should be low. If a perforation by the catheter is suspected it should be ruled out by computed tomographic scanning or transesophageal echocardiography.

Dysfunction of vasomotor reactivity in severe sepsis and septic shock

OBJECTIVE

Perfusion abnormalities are an overall phenomenon in severe sepsis and septic shock, leading to organ dysfunction. We investigated whether carbon dioxide (CO2)-induced vasomotor reactivity (VMR) is impaired in septic patients, compared with values obtained outside sepsis.

DESIGN

Prospective, clinical study.

SETTING

Six-bed neurologic critical care unit of a university hospital.

PATIENTS AND PARTICIPANTS

Eight consecutive patients with severe sepsis and septic shock.

MEASUREMENTS AND RESULTS

CO2-reactivity was measured during and outside a period of severe sepsis or septic shock according to ACCP/SCCM criteria by means of transcranial Doppler sonography and near-infrared spectroscopy (NIRS). VMR was calculated as the percentage change of cerebral blood flow velocity (normalized CO2-reactivity, NCR) and absolute changes in concentration of oxygenated hemoglobin, deoxygenated hemoglobin, total hemoglobin (HbO2, Hb, HbT) and Hbdiff (difference between HbO2 and Hb) in micromol/l per 1% increase in end-tidal CO2 (CR-HbO2, CR-Hb, CR-HbT, CR-Hbdiff). NCR and NIRS-reactivities were significantly reduced during severe sepsis and septic shock compared with values outside sepsis (mean, SD, Wilcoxon): NCR 11.0 (7.1) versus 30.7 (13.0), p < 0.02; CR-HbO2 0.70 (0.61) versus 2.33 (1.11), p < 0.02; CR-Hb -0.17 (0.74) versus -1.42 (1.28), p < 0.04; CR-HbT 0.53 (0.48) versus 1.05 (0.40), p < 0.03; CR-Hbdiff 0.91 (1.33) versus 3.75 (2.33), p < 0.02. This indicates a severely disturbed VMR.

CONCLUSIONS

In the advent of a disturbed cerebral autoregulation, critical drops in blood pressure during sepsis are transferred directly into the vascular bed, leading to cerebral hypoperfusion. This mechanism might contribute to the pathogenesis of septic encephalopathy.