Ultrasound-guided vascular access in critical illness.

Over the past two decades, ultrasound (US) has become widely accepted to guide safe and accurate insertion of vascular devices in critically ill patients. We emphasize central venous catheter insertion, given its broad application in critically ill patients, but also review the use of US for accessing peripheral veins, arteries, the medullary canal, and vessels for institution of extracorporeal life support. To ensure procedural safety and high cannulation success rates we recommend using a systematic protocolized approach for US-guided vascular access in elective clinical situations. A standardized approach minimizes variability in clinical practice, provides a framework for education and training, facilitates implementation, and enables quality analysis. This review will address the state of US-guided vascular access, including current practice and future directions.

Evidence-based consensus on the insertion of central venous access devices: definition of minimal requirements for training.

There is a lack of standard minimal requirements for the training of insertion techniques and maintenance of central venous access devices (CVADs). An international evidence-based consensus task force was established through the World Congress of Vascular Access (WoCoVA) to provide definitions and recommendations for training and insertion of CVADs. Medical literature published from February 1971 to April 2012 regarding 'central vascular access', 'training', 'competency', 'simulation', and 'ultrasound' was reviewed on Pubmed, BioMed Central, ScienceDirect, and Scopus databases. The GRADE and the GRADE-RAND methods were utilized to develop recommendations. Out of 156 papers initially identified, 83 papers described training for central vascular access placement. Sixteen recommendations are proposed by this task force, each with an evidence level, degree of consensus, and recommendation grade. These recommendations suggest central venous access education include didactic or web-based teaching with insertion procedure, infection prevention, complications, care, and maintenance of devices, along with laboratory models and tools for simulation practice incorporating ultrasound. Clinical competence should be determined by observation during clinical practice using a global rating scale rather than by the number of procedures performed. Ensuring safe insertion and management of central venous devices requires standardized education, simulation practice, and supervised insertions.

New trends in pediatric anesthesia.

The authors illustrate some relevant emerging topics in pediatric anesthesia. Endotracheal cuffed tubes have entered into routine clinical practice in younger patients. Concerns about tracheal stenosis were overcome when manufactures began to produce a new class of high volume, low pressure endotracheal tubes. Ultrasound-guided central venous cannulation helped anesthesiologists and intensivists to more efficaciously and safely perform the invasive monitoring required by ever more invasive surgical procedures. The utility of ultrasonography in peripheral nervous blocking has also been demonstrated. Better knowledge of the pathophysiology of both hypovolemic shock and coagulation dysfunction helped made it possible to face and successfully perform even major surgical procedures and treat more dramatic trauma. The introduction of devices to monitor anesthesia depth helped clinicians to better understand the pharmacodynamic effects of anesthetics, resulting in the maintenance of a more stable level of narcosis and the reduction of the incidence of awareness.

Safety and efficacy of ultrasound assistance during internal jugular vein cannulation in neurosurgical infants.

OBJECTIVE: Ultrasound guidance (USG) for internal jugular cannulation is the best solution in difficult settings where paediatric patients are involved. This is an outcome study on efficacy and complications of the USG for the internal jugular vein (IJV) cannulation in neurosurgical infants as well as an ultrasound study of anatomical findings of the IJVs in infants. DESIGN AND SETTINGS: A prospective study conducted in two Academic Neurosurgical hospitals. PARTICIPANTS: In 191 babies (body weight <15 kg), anatomical findings were studied. We performed CVC echo guided placement in 135/191 infants (weighting <10 kg). RESULTS: After a brief training period, both institutions adopted a common protocol and USG device. We obtained successful cannulation in all patients. Carotid puncture (1.5%) was the only main complication registered and minor complications were poor. Time required for cannulation was 12.5 +/- 5.7 min. Anatomical findings (in 191 patients) were IJV laterality in 34.6% cases, IJV antero-lateral in 59.7% and anterior in 5.7%. A linear relation was found between weight and internal jugular vein diameter even if R(2) = 0.43 and the model cannot be used to predict the exact size of the vein. In 62/135 babies weighting <10 kg, anatomical measurements were done in supine and Trendelemburg position. Trendelemburg position increases significantly (P < 0.001) IJV diameter, but not IJV depth. CONCLUSIONS: We considered ultrasound guidance as the first choice in infants because it can enhance IJV cannulation success, safety, and allows one to measure relationships and diameter of the IJV and optimise the central line positioning.

An outcome study on complications using routine ultrasound assistance for internal jugular vein cannulation.

BACKGROUND: Ultrasound guidance for central venous cannulation is advised by recent guidelines, but is not being applied in everyday practice. The purpose of this study was to determine the reduction in complications when applying an ultrasound locating device for internal jugular vein catheterization. METHODS: An observational study was conducted from November 2004 to October 2005 in a tertiary neurosurgical hospital on 300 patients undergoing internal jugular vein cannulation using an ultrasound technique. Patients were not randomized and operators were trained using theoretical and practical courses. Prior to the study, the investigators, who were consultant anaesthesiologists, had to perform at least 20 successful supervised cannulations. RESULTS: Cannulation was successful in all cases. The incidence of arterial puncture was 2.7%, and multiple venous punctures represented the main minor complication (14%). Bivariate analysis of the overall complications revealed no significant correlation with age group, American Society of Anesthesiologists' (ASA) classification, body mass index, or position and diameter of the vein. CONCLUSIONS: Ultrasound cannulation of the internal jugular vein minimized complications. These could be avoided when new ultrasound probes and specific needles are introduced.

Predictive value of the El-Ganzouri multivariate risk index for difficult tracheal intubation: a comparison of Glidescope videolaryngoscopy and conventional Macintosh laryngoscopy.

BACKGROUND: The predictive value of the El-Ganzouri risk index (EGRI) for difficult intubation has been evaluated using Macintosh laryngoscopy as reference standard. The Glidescope videolaryngoscope provides improved visualization of the glottis. We studied the predictive value of the EGRI using videolaryngoscopy as reference standard. METHODS: Data from two subsequent groups of patients, intubated with Macintosh laryngoscopy (ML, n = 994) and videolaryngoscopy (VL, n = 843), were retrospectively analysed. The EGRI was taken as index test. The two types of laryngoscopy were adopted as reference for the presence of Cormack and Lehane grading III-IV. For both groups, sensitivity, specificity, and positive and negative post-test probabilities (PTP) were calculated for thresholds on the EGRI scale. Receiver operating characteristic curves and corresponding areas (AUC) were obtained. RESULTS: Sensitivity and specificity were 69.7% and 66.3% at the cut-off value of 2 in the ML group, and 93.3% and 76.6% at the cut-off value of 3 in the VL group. Corresponding positive and negative PTP were 12.81% and 3.15% in the ML group, and 6.73% and 0.16% in the VL group. At the threshold of 4, positive and negative PTP were 31.34% and 4.85% in the ML group. At the threshold of 7, positive and negative PTP were 85.71% and 1.08% in the VL group. The AUC was 0.74 in the ML group and 0.91 in the VL group. CONCLUSIONS: The predictive value of the EGRI may have been underestimated due to limited accuracy of Macintosh laryngoscopy. Using videolaryngoscopy, the EGRI might be reconsidered as a decisional tool.

Velnacrine thiaanalogues as potential agents for treating Alzheimer's disease.

The only therapeutic drugs for combating dementia disease are acetylcholine esterase inhibitors (AChEI). However, the use of tacrine, the first AChEI to be launched as an Alzheimer's disease (AD) drug, has been limited by serious side effects. Therefore, efforts to search for more potent and selective inhibitors of AChE still remain highly significant in the therapeutic treatment of AD. In this work we modified the cyclohexyl ring of velnacrine, a less toxic analogue of tacrine, by synthesizing a series of thiopyranoquinolines in which the C-3 methylene unit was replaced by a sulphur atom. The anti-AChE data show that the activity was maintained with the bioisosteric substitution carried out. The introduction of a chlorine atom at different positions of the aromatic ring resulted in an array of different activities. In an attempt to understand the different behaviours displayed by the chlorine-substituted derivatives, a molecular docking study was performed.

Early translaryngeal tracheostomy in patients with severe brain damage.

OBJECTIVES: To describe the effects of early translaryngeal tracheostomy on intracranial pressure (ICP), cerebral perfusion pressure (CPP), and jugular bulb saturation (SjO2); to identify the main mechanisms affecting ICP during tracheostomy; and to evaluate the long-term effects of tracheostomy on tracheal anatomy and function. DESIGN: Prospective, observational, clinical study. SETTING: Neurosurgical intensive care unit in a teaching hospital. PATIENTS: 20 patients admitted to the ICU because of head injury, subarachnoid hemorrhage, or brain tumor with a Glasgow Coma Scale less than 8. INTERVENTIONS: Patients underwent translaryngeal tracheostomy under strict neuromonitoring. MEASUREMENTS AND RESULTS: ICP rose significantly (p < 0.05) at the critical time of cannula placement while all other parameters remained stable. At this time five patients suffered intracranial hypertension (ICP > 20 mmHg). In one of them CPP dropped below 60 mmHg. Arterial CO2 tension (PaCO2) did not rise significantly. No other major complications were recorded during the procedures. Three months after tracheostomy normal findings were detected by tracheoscopy in all cases (11 patients could be examined). CONCLUSIONS: Translaryngeal tracheostomy, performed in selected patients when the risk of intracranial hypertension was reduced to the minimum, was well tolerated in the majority of cases and did not induce persistent intracranial disorders. However, ICP is affected by tracheostomy, and careful monitoring and patient selection is necessary. At follow-up no severe anatomical or functional damage was detected.

Neurophysiological consequences of three tracheostomy techniques: a randomized study in neurosurgical patients.

We describe the effects of different tracheostomy techniques on intracranial pressure (ICP), cerebral perfusion pressure (CPP), and cerebral extraction of oxygen. We attempted to identify the main mechanisms affecting intracranial pressure during tracheostomy. To do so we conducted a prospective, block-randomized, clinical study which took place in a neurosurgical intensive care unit in a teaching hospital. The patients studied consisted of thirty comatose patients admitted to the intensive care unit because of head injury, subarachnoid hemorrhage, or brain tumor. Ten patients per group were submitted to standard surgical tracheostomy, percutaneous dilatational tracheostomy or translaryngeal tracheostomy. In every technique a significant increase of ICP (P < .05) was observed at the time of cannula placement. Intracranial hypertension (ICP > 20 mm Hg) was more frequent in the percutaneous dilatational tracheostomy group (P < .05). Cerebral perfusion pressure dropped below 60 mm Hg in eleven cases, more frequently during surgical tracheostomy. Arterial tension of CO2 significantly increased in all three groups during cannula placement. No other major complications were recorded during the procedures. At follow-up no severe anatomic or functional damage was detected. We conclude that the three tracheostomy techniques, performed in selected patients where the risk of intracranial hypertension was reduced to the minimum, were reasonably tolerated but caused an intracranial pressure rise and cerebral perfusion pressure reduction in some cases.

[Cardiopulmonary resuscitation. The effect of severe hypothermia on clinical outcome]. / La rianimazione cardiopolmonare di base. Influenza dell'ipotermia grave sull'outcome clinico.

BACKGROUND: Evaluation of outcome after CPR in severe hypothermic patients. DESIGN: Perspective study from October 1995 to April 1996. SETTING: First aid team of Italian Red Cross, Busto Arsizio (Varese), Italy. METHODS: A population of 22 patients in cardiac arrest in which CPR was performed immediately after rescue team's arrival is studied. ECG, core temperature, SpO2 and MAP were monitored whereas vital parameters were present during Basic Life Support. Outcome after CPR was evaluated with GOS scale. RESULTS: It has been observed that severe hypothermia and time of cardiac arrest impact on the clinical outcome after CPR. The high mortality rate after CPR with BLS standard is worsened by a core temperature < or = 33 degrees C. CONCLUSIONS: Severe hypothermia seems to have a dangerous effect upon outcome after cardiopulmonary resuscitation; heating systems for body temperature could prevent this situation improving CPR results.

Long-lasting antiamnesic effect of a novel anticholinesterase inhibitor (MF268).

In the present study a short (120 min) and long-lasting (360 min) antagonism of scopolamine-induced amnesia in rats was investigated in an eight-arm radial maze, by (3a S, 8a R)-1,2,3,3a,8,8a-hexahydro-1,3a,8-trimethylpyrrolo[2,3-b]indol-5-o l[8-(cis2,6-dimethyl-morpholin-4-yl)octyl]-carbamate L-bitartrate hydrate (MF268), a new cholinesterase inhibitor. Upon completing the training session, the rats were orally administered increasing doses of MF268 (2, 3, 6, 7, and 8 mg/kg) 60 min prior to s.c. injection of scopolamine (0.25 mg/kg). Following a further 60 min the rat was placed in the maze. The reversal of scopolamine-induced impairment was characterized by an inverted U-shaped dose-response curve. A significant reduction in the number of errors, and time taken to complete the maze was observed with a dose of 6 mg/kg. The compound improved memory retention without affecting scopolamine-induced hypermotility. When the same dose was administered 360 min prior to the test a significant reduction in the number of amnesic animals was observed, whereas no cognitive improvement was detected when either 1-Benzil-4-[(5,6-dimethoxy-1-indanon)-2-yl]-methyl piperidine hydrochloride (E2020) (0.25 mg/kg) or tacrine (0.5 mg/kg) were administered 360 min prior to the test. The kinetics of whole-brain cholinesterase confirmed the long-lasting activity for MF268. A clinical relevance for the use of MF268 in AD treatment is suggested.

An inverted U-shaped curve for heptylphysostigmine on radial maze performance in rats: comparison with other cholinesterase inhibitors.

The potential of heptylphysostigmine tartrate (pyrrolo [2,3b] indol-5-ol, 3,3a,8,8a-hexahydro-1,3a,8-trimethylheptylcarbamate [ester, (3aS-cis)]) (MF201), a new second-generation cholinesterase inhibitor, to antagonize scopolamine-induced amnesia in rats was assessed in an 8-arm radial maze. Upon completing the training session, the rats were orally administered increasing doses of MF201 (2, 3, 4, 6 and 8 mg/kg) 60 min prior to a s.c. injection of scopolamine (0.25 mg/kg). 9-Amino-1,2,3,4-tetrahydroamino-acridine hydrochloride hydrate (tacrine) (0.25, 0.37, 0.5, 1 and 2 mg/kg), 1-benzil-4-[(5,6-dimethoxy-1-indanon)-2-yl]-methyl piperidine (E2020) (0.125, 0.18, 0.25 and 0.5 mg/kg) and physostigmine (0.15, 0.25, 0.5 and 1 mg/kg) were orally administered and rats were tested in the same task. As previously described, scopolamine induced an impairment in radial maze performance, measured in terms of total number of errors, total time taken to complete the task and the percentage of amnesic animals. The reversal of scopolamine-induced impairment was characterized by the presence of an inverted U-shaped dose-response curve. A significant antagonistic effect was achieved with a dose (mg/kg) of 0.25 for E2020, 0.5 for tacrine and physostigmine and 3, 4 and 6 for MF201, the latter manifesting a broader spectrum of activity (3-6 mg/kg). While the maximal active doses restored the scopolamine-induced modified pattern of arm entry, they were ineffective in reducing hypermotility, suggesting the drugs have a specific effect on cognitive function.