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Biomedical subjects

R M Keltner

Publications and source records attributed to R M Keltner.

15 recordsLinked to original sources
PubMed1990

A comparison of transcranial Doppler ultrasound (TCD) and radioactive microspheres in determining cerebral perfusion in normal and low flow states.

We have previously utilized the technique of transcranial Doppler (TCD) ultrasound to determine cerebral perfusion in patients undergoing cardiopulmonary resuscitation (CPR). In order to assess if TCD can reliably measure alterations in cerebral perfusion under conditions of normal and low cardiac outputs, we compared TCD measured blood flow velocities in the middle cerebral artery (MCA) of six piglets with radioactive microsphere determinations of total cerebral perfusion at baseline normal sinus rhythm (NSR), during CPR, and following return of spontaneous circulation (ROSC). Peak systolic and mean blood flow velocities were compared to the microsphere perfusion results on 15 different occasions; six during NSR, five during CPR, and four following ROSC. Although qualitative alterations in TCD measurements reflected changes in microsphere perfusion, we could not find a statistically significant correlation between either peak systolic or mean MCA blood flow velocities and microsphere perfusion measurements either overall or in any subgroup. The possible reasons which may explain the findings are discussed.

Animals↗
PubMed1990

High pressure percutaneous transtracheal ventilation: the use of large gauge intravenous-type catheters in the totally obstructed airway.

Percutaneous transtracheal ventilation using a large gauge intravenous-type catheter can be used successfully in the setting of complete upper airway obstruction in animals. In this study, using a large animal model, satisfactory oxygenation and ventilation was achieved by inversely varying the catheter size and the inspiration to expiration ratio (I:E). Specifically, 30 to 63 kg ruminants with an obstructed upper airway were resuscitated for 30 minutes from a hypoxic, hypercarbic, and acidotic state using 12- and 14-gauge catheters connected to a 50 psi oxygen source via a two-way valve with an I:E of 1:4 and 1:9 seconds, respectively. Shorter expiratory time or increased inspiratory time with these intravenous catheters resulted in significant hemodynamic compromise, barotrauma, inadequate carbon dioxide elimination, acidemia, and frequent death.

Airway Obstruction↗
PubMed1977

Short tube decompressive jejunostomy.

Experience with short tube decompressive jejunostomy in twenty-nine patients with small bowel obstruction is presented. Many advantages are gained by operative decompression of obstructed, dilated small bowel. The favorable results with its use make short tube decompressive jejunostomy a safe, acceptable method of decompressing dilated small bowel.

Adult↗
PubMed1975

The effect of an intraduodenal elemental diet on pancreatic secretion.

The effect of an elemental diet on canine exocrine pancreatic secretion was evaluated by infusing an elemental diet into the duodenum of dogs and monitoring the output of the pancreas. The stimulatory properties of the elemental diet were compared with a nearly equimolar dose of an L-form neutral amino acid, 0.16 normal hydrochloric acid, and 2 units per kilogram per hour of exogenous cholecystokinin. Intraduodenal infusion of elemental diet produced significant increases in pancreatic volume and protein output. These changes were similar to those produced by the amino acid solution and suggest that the stimulatory properties of the elemental diet are primarily due to the amino acid content. The results of the this study suggest that elemental diets stimulate the duodental mucosa to secrete cholecystokinin which stimulates the exocrine pancreas. Elemental diets administered in such a manner that the substance passes through the duodenum would not theoretically be a satisfactory method of providing calories to patients with acute pancreatitis.

Animals↗