ABSTRACT
The human femoral artery can bleed dangerously following the removal of a catheter uring cardiac catheterization. In this study, a modified technique of needle insertion, simply inserting the needle bevel-down instead of the standard bevel-up approach, was tested as a means to reduce bleeding after catheter removal. Large bore needle punctures were made in surgically exposed arteries of anesthetized pigs using either a standard technique (45 degree approach, bevel up) or a modified technique (25 degree approach, bevel down). For half the punctures, topical phenylephrine solution (1 mg/ml) was applied to the adventitia of the artery to cause constriction. Median bleeding rates were reduced from 81 to less than 1 ml/min/100 mmHg intraluminal pressure by the modified technique with application of phenylephrine. In most cases zero bleeding, that is self-sealing, of the arteries occurred. It is postulated that a flap-valve of tissue created by the modified technique produced this self-sealing behavior. Sophisticated modeling studies are needed to fully understand this new phenomenon.
Subject(s)
Carotid Artery Injuries/etiology , Hemorrhage/prevention & control , Needles/adverse effects , Punctures/adverse effects , Punctures/methods , Wounds, Penetrating/etiology , Animals , Arteries/injuries , Carotid Arteries/drug effects , Carotid Artery Injuries/prevention & control , Computer Simulation , Elasticity , Finite Element Analysis , Hemorrhage/etiology , Hemostasis/physiology , Models, Cardiovascular , Phenylephrine/pharmacology , Swine , Wound Healing/physiology , Wounds, Penetrating/prevention & controlABSTRACT
UNLABELLED: Electroventilation is the technique of producing inspiration with stimuli applied to inspiratory muscles by using strategically placed electrodes on or within the body. We conducted studies using the dog to determine the efficacy of monopolar and bipolar intratracheal electrodes for electroventilation. Bipolar electrodes were able to produce an inspired volume greater than a spontaneous tidal volume in all seven dogs, but monopolar electrodes were able to in only three of seven dogs. The intratracheal electrode has the advantage over body-surface electrodes that less current is required to produce a single tidal volume, and it has the advantage over intraesophageal electrodes that anatomical placement of the electrode is simplified. These experiments demonstrated that a bipolar electrode can be used for electroventilation. IMPLICATIONS: This study demonstrates that electroventilation is possible with intratracheal electrodes, decreasing the current needed to electroventilate by using body-surface electrodes. Two different methods of intratracheal electroventilation can be used: monopolar, in which the return electrode is on the body surface; and bipolar, in which the return electrode is in the trachea.
