Relationship between peripheral and central venous pressures in different patient positions, catheter sizes, and insertion sites

OBJECTIVE: To investigate the relationship between peripheral and central venous pressures in different patient positions (supine, prone, lithotomy, Trendelenburg, and Fowler), different catheter diameters (18 G and 20 G), and catheterization sites (dorsal hand and forearm) during surgical procedures. DESIGN: Prospective clinical study. SETTINGS: University hospital. PARTICIPANTS: Five hundred adult patients. INTERVENTIONS: Peripheral over-the-needle intravenous catheters were placed in the dorsal hand or forearm. Central venous catheters were inserted via the internal jugular or subclavian vein after induction of anesthesia. MEASUREMENTS and MAIN RESULTS: Simultaneous measurements of central and peripheral venous pressures were made during stable conditions at random time points in surgery; 1953 paired measurements were performed. Mean central venous pressure was 11 +/- 3.7 mmHg and peripheral venous pressure was 13 +/- 4 mmHg (p = 0.0001). The overall correlation between central venous and peripheral venous pressures was found to be statistically significant (r = 0.89, r(2) = 0.8, p = 0.0001). Mean difference between peripheral and central venous pressure was 2 +/- 1.8 mmHg. Ninety-five percent limits of agreement were 5.6 to -1.6 mmHg. CONCLUSION: It has been assumed that replacing central venous pressure by peripheral venous pressure would cause problems in clinical interpretation. If the validity of this data is confirmed by further studies, the authors suggest that central venous pressure could be estimated by using regression equations to compare the 2 methods.     

Intracranial calcification and tumoural calcinosis during vitamin D therapy

Extraskeletal calcifications are frequently observed in patients with chronic renal failure. However, clinically, they usually remain silent. In this report, we describe two patients with massive extraskeletal calcifications that caused significant morbidity. The first patient had tumoural calcification located on the shoulder and the second patient had severe neurological symptoms caused by intracranial calcifications. High calcium phosphorus product and severe secondary hyperparathyroidism were present in both patients. Furthermore, they both received inappropriately high doses of active vitamin D, even though they failed to respond to this therapy. We suggest to monitor closely the calcium, phosphorus and parathyroid hormone levels during calcitriol therapy and to perform parathyroidectomy, without delay, in patients who were resistant to calcitriol.     

In vitro reactivation of acetylcholinesterase inhibited by cyclosarin using bisquaternary pyridinium aldoximes K005, K033, K027 AND K048

We have tested four new bisquaternary pyridinium acetylcholinesterase (AChE; EC 3.1.1.7) reactivators - K005 (1,3-bis(2-hydroxyiminomethylpyridinium) propane dibromide), K033 (1,4-bis(2-hydroxyiminomethylpyridinium) butane dibromide), K027 (1 -(4-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium) propane dibromide) and K048 (1-(4-hydroxyiminomethylpyridinium)-4-(4-carbamoylpyridinium) butane dibromide) as the potential reactivators of AChE inhibited by cyclosarin. Their reactivation potencies were studied using standard in vitro reactivation test. Rat brain homogenate was used as the source of the enzyme. Oxime K033 seems to be the most potent reactivator of cyclosarin-inhibited AChE. Its reactivation potency is significantly higher than the efficacy of all other tested AChE reactivators.     

Diffusion tensor fiber tracking shows distinct corticostriatal circuits in humans

A landmark of corticostriatal connectivity in nonhuman primates is that cortical connections are organized into a set of discrete circuits. Each circuit is assumed to perform distinct behavioral functions. In animals, most connectivity studies are performed using invasive tracing methods, which are nonapplicable in humans. To test the proposal that corticostriatal connections are organized as multiple circuits in humans, we used diffusion tensor imaging axonal tracking, a new magnetic resonance technique that allows demonstration of fiber tracts in a noninvasive manner. Diffusion tensor imaging-based fiber tracking showed that the posterior (sensorimotor), anterior (associative), and ventral (limbic) compartments of the human striatum have specific connections with the cortex, and particularly the frontal lobes. These results provide the first direct demonstration of distinct corticostriatal connections in humans.     

Neurovascular coupling analyzed non-invasively in the human brain

Most functional brain imaging methods detect neuronal activations indirectly through the accompanying neurovascular response. Here, we demonstrate that a novel methodological approach, the combination of DC-magnetoencephalography (DC-MEG) and near-infrared spectroscopy (NIRS), allows non-invasive assessment of the dynamics of neurovascular coupling in the human brain: detecting directly slow neuronal processes (with time constants of 30s), DC-MEG revealed, even in unaveraged recordings, sustained neuronal activations at pericentral hand cortices contralateral to repetitive finger movements; these were accompanied by the ensuing local vascular response showing similar dynamical features as quantified by simultaneously recorded NIRS. This non-invasive approach opens a new avenue for the understanding of neurovascular coupling during physiological tasks as well as in diseases involving slow neuronal depolarization shifts and alterations of blood flow, such as stroke or migraine.     

Magnetic resonance imaging in prenatal diagnosis

Author discusses methods of magnetic resonance imaging and in status in the prenatal diagnosis as well as the impact of examination on the management plan for treatment of fetus and newborn.     

Dorsal bony septum: a split cord malformation variant

Split cord malformations (SCMs) are rare spinal anomalies and their classification is still a matter of debate. There is no widespread consensus on the embryological basis of this entity. The unified theory, proposed by Pang et al. [Neurosurgery 1992;31:451-480], was an attempt to explain the embryogenetic mechanism as a basic error occurring around the time when the primitive neuroenteric canal closes. We report two unusual cases of SCMs with a dorsally situated bony spur. We analyzed the radiological, clinical and surgical features of the lesions and were not able to classify these cases according to the unified theory. Further embryological studies should be conducted to elucidate the mechanisms of occurrence of these lesions, and the dorsal bony septum variant should be considered in SCM surgery.     

Toxocariasis - an underestimated problem in paediatrics

Aspects of Toxocara spp. epidemiology and paratenic infestation of children are described. Human toxocariasis is caused by infestation of zoonotic roundworms of dogs and cats. Soil sampling showes widespread contamination of the environment, particularly parks and playgrounds, with the eggs of Toxocara spp. Toxocara seroprevelance values in children vary between 3.5% in the West Poland and 19% in the South-East Poland. Children more frequently have clinical symptoms o the disease because of the closer contact with contaminated soil in sand-boxes and relatively frequent geophagia. A 3 years old girl with covert toxocariasis is described. As this case illustrates, this disease can be present without its classic visceral, ocular or neurological manifestations. On admission to the hospital the results of blood tests were as follows: white blood cells count, 43x10(3)/ mm3 (norm <13x10(3)) and hyperosinophilia, 81%. The girl was treated with albendazole 15 mg/kg for five days, after one year the treatment was repeated. The patient was followed with blood samples throughout a period of one and half year. During that time results of serological tests for Toxocara canis were strongly positive. The lowest blood count was 20.0x10(3)/mm3 and eosinophilia, 19%. Possible association between high eosinophilia in toxocariasis and development of allergic and cardiovascular diseases is discussed.     

Hyperhomocysteinaemia in a coeliac disease heterozygote for the two common mutations (677C->T and 1298A->C) of the methylenetetrahydrofolate reductase gene. Case report

A 17 year old girl with coeliac disease was found to have hyperhomocysteinaemia (fasting plasma total homocysteine concentration - 19.93 micromol/L; N<12.75 micromol/L). At the age of 1 5 she gave up gluten-free diet and had only subtle signs of chronic malabsorption such as folic acid and iron deficiency. The patient was heterozygote for both common mutations (677C->T and J298A->C) of the methylenetetrahydrofolate reductase gene. On gluten diet an intake of 5 mg folic acid/d from supplements for two weeks resulted in an increase in serum folate and a reduction in homocysteine concentration (13.20 micromol/L). The patient continued to consume a gluten containing diet and 0.5mg folic acid/d from supplements for 4 months and homocysteiene decreased to 12.1 mmol/L. Hyperhomocysteinaemia - a cardiovascular and obstetrical risk factor - might be a significant problem for patients with celiac disease on gluten-containing diet.