Wolfram Schummer

International evidence-based recommendations on ultrasound-guided vascular access

PurposeTo provide clinicians with an evidence-based overview of all topics related to ultrasound vascular access.MethodsAn international evidence-based consensus provided definitions and recommendations. Medical literature on ultrasound vascular access was reviewed from January 1985 to October 2010. The GRADE and the GRADE-RAND methods were utilised to develop recommendations.ResultsThe recommendations following the conference suggest the advantage of 2D vascular screening prior to cannulation and that real-time ultrasound needle guidance with an in-plane/long-axis technique optimises the probability of needle placement. Ultrasound guidance can be used not only for central venous cannulation but also in peripheral and arterial cannulation. Ultrasound can be used in order to check for immediate and life-threatening complications as well as the catheter’s tip position. Educational courses and training are required to achieve competence and minimal skills when cannulation is performed with ultrasound guidance. A recommendation to create an ultrasound curriculum on vascular access is proposed. This technique allows the reduction of infectious and mechanical complications.ConclusionsThese definitions and recommendations based on a critical evidence review and expert consensus are proposed to assist clinicians in ultrasound-guided vascular access and as a reference for future clinical research.

Dysfunction of vasomotor reactivity in severe sepsis and septic shock.

Abstract. 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 µmol/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.

Is Traditional Reading of the Bedside Chest Radiograph Appropriate To Detect Intraatrial Central Venous Catheter Position

BACKGROUND Traditionally, the positioning of central venous catheters (CVCs) outside the right atrium (RA) in patients receiving intensive care is determined by surrogate landmarks on bedside chest radiographs (CXRs). The validity of this method was examined by comparing readings of radiologists with the results of transesophageal echocardiography (TEE). METHODS Prospective study at university hospital. Two hundred thirteen adults scheduled for cardiothoracic surgery were randomized to right or left internal jugular vein catheterization under ECG guidance. One senior radiologist and two radiologists in training independently read the CXRs, and determined whether the CVC tip ended in the RA and measured the vertical distance from the CVC tip to the carina (TC-distance). RESULTS Two hundred twelve CVC tips could be identified by TEE. Only left-sided CVCs (n = 5) ended in the upper RA (2.4%). Three of those patients were shorter than 160 cm. Specificity was 94% for senior radiologist, 44% for the first radiologist in training, and 60% for the second radiologist in training. The TC-distance of intraatrial catheters was 39, 55, 59, 80, and 83 mm, respectively. Thus, a TC-distance < or = 55 mm ensured extraatrial tip position in four of five intraatrial CVCs (80%, p = 0.002). The TC-distance of extraatrial catheters ranged from - 26 to 102 mm. CONCLUSIONS Reading of a bedside CXR alone is not very accurate to identify intraatrial CVC tip position. TC-distance is a helpful marker, and its specificity is as good as that of an experienced radiologist if a cutoff value of 55 mm is chosen.

The Pivotal Role of Vasopressin in Refractory Anaphylactic Shock

BACKGROUND: Severe anaphylaxis can be associated with cardiovascular collapse that is difficult to manage and does not respond to treatment with epinephrine. Because anaphylaxis is uncommon, unpredictable and may be fatal, a prospective, randomized, controlled trial in humans on the best management is difficult and guidelines are based on theory and anecdotes only. METHODS AND RESULTS: We report six cases in which the use of vasopressin was successful in the treatment of anaphylactic shock. CONCLUSIONS: Standard treatment of anaphylactic shock, including discontinuation of the causative agent, administration of epinephrine, and infusion of IV fluids, did not stabilize cardiocirculatory function, and adding arginine vasopressors resulted in prompt hemodynamic stabilization.

Anterior spinal artery syndrome following periradicular cervical nerve root therapy

Sirs: A 44-year-old man suffered from intractable neck pain with irradiation into his left arm due to discogenic compression of the left C7-nerve root. It was decided to treat the patient with CT-controlled periradicular therapy (PRT). The tip of a 22-gauge needle was positioned in the posteriorcaudal corner of the left C6/C7foramen. After adequate position of the needle had been confirmed by injection of 0.2 ml iotrolan (Isovist 300, Schering, Germany), a mixture of 1 ml mepivacaine 1 % and 0.5 ml triamcinolone acetonide (20 mg) crystal suspension was injected without adrenaline admixture. Within 3 minutes the patient developed an anterior spinal artery syndrome with complete flaccid quadriplegia including respiratory muscles, paralysis of sphincteric function, and dissociated sensory loss below the level of C4. Colorcoded duplex sonography of the vertebral arteries was normal. T2weighted MRI of the spine performed 6 hours after the onset of symptoms showed longitudinal central signal enhancement of the cervical spinal cord (Fig. 1A). MRI performed 6 days after the incident LETTER TO THE EDITORS

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.

Extravasation injury in the perioperative setting.

Extravasation is an unintentional injection or leakage of fluid in the perivascular or subcutaneous space. Extravasation injury results from a combination of factors, including solution cytotoxicity, osmolality, vasoconstrictor properties, infusion pressure, regional anatomical peculiarities, and other patient factors. We reviewed the hospital files of patients who had sustained a significant extravasation injury in the perioperative setting at two German hospitals. These cases highlight the risk of devastating consequences from extravasation injury. Vasoactive drugs and hyperosmolar and concentrated electrolyte solutions are the predominant vesicants in the perioperative setting. Prompt and appropriate intervention is important for avoiding or minimizing extensive tissue injury.

The anterior jugular venous system: variability and clinical impact.

The anterior jugular venous system, with its interconnections to the subclavian and deep jugular veins, provides a collateral venous network across the midline of the neck area, which is especially important in unilateral occlusion of an innominate vein. We illustrate the variability of this system and its clinical impact on catheterization by three cases of landmark-guided central venous cannulation. Case 1: Cannulation of the left internal jugular vein with a central venous catheter and of the left innominate vein (LIV) with a pulmonary artery catheter resulted in correctly positioned catheter tips. However, these catheters were actually not placed in the innominate vein but coursed through the jugular venous arch. Case 2: Cannulation of the left subclavian vein was complicated by resistance of guidewire advancement at 13 cm. Occlusion of the LIV and enlargement of the jugular venous arch were present. Case 3: Insertion of a pulmonary artery catheter and a central venous catheter through the LIV. The pulmonary artery catheter was correctly placed. The tip of the central venous catheter was mistakenly positioned in the left anterior jugular vein. We describe the normal anatomy of the anterior jugular venous system and its role as a major collateral. Correct placement of central venous catheters may be possible via the anterior jugular venous system. Conversely, central venous catheters malpositioned in the anterior jugular vein can increase the risk for complications and should be removed.

Two cases of delayed diagnosis of postpartal streptococcal toxic shock syndrome

BACKGROUND: Puerperal sepsis due to group A beta-hemolytic streptococcal (GAS) toxic shock syndrome is associated with very high morbidity and mortality. Luckily it is now rare, but diagnosis is not always easy. This report demonstrates the problem of recognizing this disease, and summarizes the current knowledge on the pathomechanism and management of streptococcal toxic shock syndrome. CASE: Two cases of postpartum streptococcal toxic shock syndrome due to GAS are described. In both cases the correct diagnosis was delayed for several days. The first patient was sent home with the diagnosis of German measles; the second patient was transferred to our neurological intensive care unit with the diagnosis of meningitis. Both patients were admitted to the intensive care unit in profound shock, both developed multiple organ failure, and one patient died. CONCLUSIONS: GAS may produce virulence factors that cause host tissue pathology. Besides aggressive modern intensive care treatment, early diagnosis and correct choice of anti-streptococcal antibiotics are crucial. A possible adverse effect of non-steroidal anti-inflammatory agents requires confirmation in a multicenter study.

Cerebral venous flow velocity predicts poor outcome in subarachnoid hemorrhage.

Background and Purpose— Predictors of clinical outcome in aneurysmal subarachnoid hemorrhage (SAH) vary in reliability. Measurement of cerebral venous hemodynamics by transcranial color-coded duplexsonography (TCCS) has become of increasing interest lately, and correlation with intracranial pressure (ICP) seems to be high. The aim of the presented study was to assess changes of cerebral venous hemodynamics in SAH and evaluate its relationship with clinical outcome. Methods— We performed sequential TCCS of venous peak flow velocities (vp-FVs) in the transversal sinus in 28 consecutive patients with aneurysmal SAH (Hunt and Hess scale 1 to 5). Measurement was initiated at onset of arterial vasospasm up to 5 days after SAH. All patients had a continuous ICP monitoring. Clinical outcome was evaluated with the modified ranking scale (MRS) 30 days after SAH. Patients were divided according to outcome: group I good recovery (MRS 0-III) and group II poor outcome (death or MRS IV-V). Maximum vp-FV, time-averaged vp-FV (mv-FV), and ICP were compared between groups. Results— Vp-FV and mv-FV as well as ICP of group II exceeded values of group I (P <0.001 for all 3 parameters). Vp-FV showed a positive correlation with ICP (r =0.63; P <0.001). A vp-FV exceeding 35.4 cm/s (sensitivity 100%; specificity 90.9%), an mv-FV exceeding 27.3 cm/s (sensitivity 94.1%; specificity 81.8%), and an ICP exceeding 24 mm Hg (sensitivity 87.5%; specificity 81.8%) predicted poor outcome (receiver operating characteristic analysis). Conclusions— Increased ICP values correlate with increased venous flow velocities. In SAH, increased ICP and increased venous flow velocities are associated with poor outcome. Flow velocity of the transversal sinus is a highly sensitive, reliable, and early predictor of outcome in SAH.