Impact of constant storage temperatures and multiple warming cycles on the quality of stored red blood cells.

BACKGROUND: Red blood cells (RBCs) are routinely stored in liquid state at temperatures below 6°C, and RBC unit core temperature should not exceed 10°C during transport. Since the critical temperature of 10°C was chosen mostly arbitrarily, this study investigated the effect of both constant temperature settings as well as multiple rewarming cycles on stored RBCs with respect to morphology, biochemical parameters and haemolysis. MATERIALS AND METHODS: Buffy coat-depleted filtered RBCs were used as standard products. RBCs were stored at 1-6°C (reference group, n = 12), 13 and 22°C (test groups, n = 12 each) or stored at 1-6°C and warmed up five times to 10, 13, or 22°C for a period of 24 h each. Various biochemical parameters were measured weekly. RBCs were further investigated using electron microscopy. RESULTS: Red blood cells stored constantly at 13 or 22°C showed stable haemolysis rates until day 28 and day 14, respectively. RBCs stored at 1-6°C with five warming-up periods to 10, 13 or 22°C each lasting 24 h (total 120 h) did not exceed the limit of the haemolysis rate at the end of storage. Differently shaped erythrocytes were found in all samples, but more crenate erythrocytes appeared after 42 days of storage independent of temperature profiles. CONCLUSION: Red cells can be kept at constant temperatures above 6°C without apparent harmful effects at least until day 14, whereas multiple warming cycles for no longer than 24 h at 10, 13 or 22°C with subsequent cooling do not cause quality loss as assessed using the in vitro assays employed in this study.

Core and surface temperatures in a red-blood-cell unit during storage and transport.

BACKGROUND AND OBJECTIVES: Temperature tracing of stored red-blood-cell concentrates (RBCs) is inevitable with respect to RBC quality control. RBC temperature, which should not exceed 10°C, is usually assessed by devices attached to the surface of the RBC pouch, assuming that surface temperature adequately represents the thermal state of RBC. We investigated under which conditions this assumption is true. MATERIALS AND METHODS: Eighteen thermocouples (TC) equidistantly mounted on a two-layer plastic grid were installed in a pouch to determine temperature distribution in the unit. Two TCs were attached to each side of the bag to evaluate surface temperatures. One was further installed in each investigation room to assess ambient room temperatures. Temperature distributions and time-temperature courses were measured under constant temperatures and various warming and cooling conditions. RESULTS: At homogeneous storage temperatures, only small gradients were measured between core and surface temperatures. Removed from cooling chamber to room temperature or back from room to storage temperature, core and surface time-temperature curves drifted apart. Surface and core temperature diverged the more, the faster ambient temperatures altered. The situation could be stabilized by thermal isolation: handled in a transport box, or even better in an air cushion envelope, surface and core courses approached and ultimately closely followed each other, respectively. CONCLUSION: RBC temperature monitoring devices attached to the surface of the RBC pouch very well describe the core temperature under constant temperature conditions. During transport, thermal isolation of the RBC unit is necessary to control RBC temperature precisely by surface temperature measurements.

Influence of bileaflet prosthetic mitral valve orientation on left ventricular flow--an experimental in vivo magnetic resonance imaging study.

OBJECTIVE: Orientation-related bileaflet mechanical valve flow and velocity studies in the downstream area are limited in mitral valve replacement studies. METHODS: In five sheep, ventricular blood flow was visualized prior to the implantation of a mitral Edwards Mira Bileaflet Mechanical Valve Model 9600. The implant orientation was either anatomic, with a 45 degrees rotation, or anti-anatomic, with a 90 degrees rotation. Sheep were positioned within an 1.5T field strength MR scanner (Magnetom Sonata; Siemens) to assess time-dependent three-dimensional blood flow velocities displayed as color-encoded vectors. RESULTS: The preoperative ventricular velocity profiles presented negligible individual variances. Streamlines passed homogeneously without any spatial differences into the left ventricle. Starting from the anatomical position, the areas with inhomogeneous and accelerated local blood velocities increased in comparison to the preoperative status. Rotating the prosthesis until it was in a 45 degrees position caused a significant increase in turbulence immediately downstream; fluids stagnated longer at the apex. In the anti-anatomic orientation, mean velocities decreased. In all three positions, but less so in the anatomical position, the flow pattern of the blood helix at the apex was disturbed. The intraventricular flow patterns between prostheses in the three orientations were, however, not significant when compared to the differences between physiologic intraventricular flow and any of the postoperative measurements. CONCLUSIONS: To achieve optimal hemodynamics, rotation of the mitral valve has to be considered carefully, as has long been known from aortic valve replacement studies. To this end, a method for qualitative assessment of left ventricular blood flow patterns was developed.

Cardiac MR in robotic heart surgery for preoperative identification of the target vessel and precise port placement--a theoretical model.

BACKGROUND: The identification of the ideal anastomosis site and the proper port placement are critical for the success of closed-chest robotic surgery. We investigated a new systematic procedure for precise port placement for TECABs. METHODS: We used trigonometry and a human thoracic model to determine the optimal working angles between anastomotic plane, instruments, and endoscope. We then applied the results to seven human subjects as follows: 1. A navigation grid was located extrathoracically before cardiac MR examination. 2. The ideal anastomosis site was defined with the MR. Intrathoracic distances and angles were computed with cardiac MR software and projected onto the thorax. 3. The ideal port placement points were marked on the thorax. RESULTS: The optimal working angle between endoscope and instruments was 35 degrees. 0 degrees and 90 degrees angles were associated with a significant reduction in visualization, technical ease, quality and anastomosis time. The course of the LAD was identified in all seven volunteers with MR. Mean deviation of the endoscope port from the medioclavicular line was 4.3+/-2.1 cm and of the instrument ports from the anterior axillary line 8.4+/-2.4 cm. CONCLUSIONS: Cardiac MR in combination with the navigation grid proved suitable for the visualization of coronary vessels for individually calculating port placement points on the thorax.

Dimeric versus monomeric nonionic contrast agents in visualization of coronary arteries.

A cubital intravenous iodine contrast agent enhancement is used to visualize coronary arteries using EBT. The quality of the coronary artery visualization however is limited by the nearly simultaneous approximation of CT values in coronary arteries and myocardial tissue. The objective of the study was to evaluate if "under real clinical circumstances" the lower iodine concentration and the dimeric based characteristic of iodixanol may effect the kinetic of the applied contrast agent and the visualization of coronary arteries studied noninvasively by EBT. A double-blind, randomized, parallel study was performed in 111 cardiac patients, using iodixanol 270 mg I/ml or iohexol 300 mg I/ml. The kinetics of contrast enhancement was studied in the flow mode measuring following parameters: mean arrival time and mean time to reach peak CT values in the pulmonary trunk, transit time from the pulmonary trunk to the aorta as well as mean and maximum CT values in the left ventricular chamber and in the myocardium with respect to the body mass index. The mean difference of CT values in the left ventricular chamber and the myocardium was calculated. The length of the visualized coronary arteries was assessed and the diagnostic quality of coronary artery visualization scored on a visual analogue scale. Although iodixanol was used with a lower iodine concentration than iohexol there was no significant statistical difference between both groups with respect to the diagnostic visualization and length assessment of the coronary arteries as well as in the mean difference of CT values in the left ventricular chamber and the myocardium. This means that the advantageous dimeric characteristics of iodixanol may be used to reduce the amount of applicated iodine in contrast agents without loss of diagnostic image quality and information.

[Haptic form discrimination. Group comparison of children with normal speech development and former speech development disordered patients]. / Haptische Formdiskrimination. Gruppenvergleich von sprachunauffälligen und ehemals sprachentwicklungsgestörten Kindern.

The importance of the neurobiological basis of developmental language disorders includes somatosensory modalities. Twenty-five children were diagnosed as having specific language-impairment at preschool age. All were examined with regard to their manual haptic form discrimination without visual control at a mean age of 8.7 years +/- 7.1 months. This study group was compared to age- and gender-matched normal children of equal non-verbal intelligence (control group). Haptic discrimination was measured with the Seguin formboard on which the children were required to place ten geometrical forms in appropriate holes. Both groups differed significantly in their mean quantitative performances in favor of the control group (P < 0.05). The difference in their mean performance and their mean discrimination times did not reach statistical significance. All results were not age-dependent. The control group on average performed significantly better with their left hands than the study group (P < 0.05). Qualitative analysis revealed a significant difference in haptic discrimination of the pointed forms and was probably caused by inadequate exploration procedures and/or cognitive representation deficits. The results of the children with previous developmental language disorders were interpreted as an expression of an impaired cerebral maturation.

[Topography of orbital contents. II: Compartments of the orbital adipose body]. / Topographie des Orbitainhaltes. Teil II: Uber die Kammerung des Corpus adiposum orbitae.

In coronal and paramediansagittal sections the intraorbital fatty tissue and compartments were examined. Discussed are the septa by the neurosurgical approach, the most important fastening apparatus of the eyeball and blow-out fractures.

[Topography of the orbital contents. I: Eye muscles, orbital walls and internal contents]. / Topographie des Orbitainhaltes. Teil I: Musculi bulbi, Orbitawände und -inhalt.

The distances between the sclera of the bulb and the orbital walls and between the sclera and the external orbital muscles, the width of the orbital muscles and their distances to the orbital walls were measured. Values are given in millimeters (liminals). Discussed are the surgical approaches to the orbital contents.

[Intracisternal length of cranial nerves 7-12]. / Uber die intrazisternale Länge der Hirnnerven VII-XII.

The course of the seventh to twelfth cranial nerves in the posterior fossa is described. The relation between the nerves and the cranial vessels, as well as their importance in practical medicine are discussed.

[Course of the abducens nerve before the exit zone from the central nervous system to the lateral rectus muscle]. / Uber den Verlauf des N. abducens vor der Austrittszone aus dem zentralnervösen Organ bis zum M. rectus lateralis.

The intracisternal, intrasinusoidal and intraorbital course of the sixth nerve is described, including the relative position in respect of the arachnoid membrane and the cerebral arteries. In addition, the relationships of the nerve in relation to possible injuries is considered.

[Intracisternal length of the trigeminal nerve]. / Uber die intrazisternale Länge des N. trigeminus.

The mean length of the fifth nerve in the posterior fossa is 13.38 mm (medial portion) and 12.01 mm (lateral portion). Measurements of the triangular part of the trigeminal nerve, its branches and its central (vulnerable) part, are also described.

[Intracisternal length of the brain path and nerve tracts of the I to IV cranial nerves]. / Uber die intrazisternale Länge von Hirnbahn- und Nervenstrecken der Hirnnerven I--IV.

The olfactory bulb has a length of 12.27 mm whereas the length of the olfactory tract from the beginning to where it crosses the optic nerve is 21.2 mm (mean). The intracranial portion of the optic nerve is 10.3 mm long. From the brain stem to its dural exit the III nerve measures 18.82 mm, and the IV nerve 32.65 mm. The range of variation in the lengths of the nerves, as well as their immediate relations are included in the investigation.

[Course of the cranial nerves in the lateral wall of the cavernous sinus]. / Uber den Verlauf der Hirnnerven in der Seitenwand des Sinus cavernosus.

The course and lengths or the cranial nerves in the lateral wall of the cavernous sinus (Parkinson's triangle) and their relations to the internal carotid artery are described.