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R W Hilwig

Publications and source records attributed to R W Hilwig.

35 records · Page 2Linked to original sources
PubMed1993

Bystander cardiopulmonary resuscitation. Is ventilation necessary?

BACKGROUND: Prompt initiation of bystander cardiopulmonary resuscitation (CPR) improves survival. Basic life support with mouth-to-mouth ventilation and chest compressions is intimidating, difficult to remember, and difficult to perform. Chest compressions alone can be easily taught, easily remembered, easily performed, adequately taught by dispatcher-delivered telephone instruction, and more readily accepted by the public. The principal objective of this study was to evaluate the need for ventilation during CPR in a clinically relevant swine model of prehospital witnessed cardiac arrest. METHODS AND RESULTS: Thirty seconds after ventricular fibrillation, swine were randomly assigned to 12 minutes of chest compressions plus mechanical ventilation (group A), chest compressions only (group B), or no CPR (group C). Standard advanced cardiac life support was then provided. Animals successfully resuscitated were supported for 2 hours in an intensive care setting, and then observed for 24 hours. All 16 swine in groups A and B were successfully resuscitated and neurologically normal at 24 hours, whereas only 2 of 8 group C animals survived for 24 hours (P < .001, Fisher's exact test). One of the 2 group C survivors was comatose and unresponsive. CONCLUSIONS: In this swine model of witnessed prehospital cardiac arrest, the survival and neurological outcome data establish that prompt initiation of chest compressions alone appears to be as effective as chest compressions plus ventilation and that both techniques of bystander CPR markedly improve outcome compared with no bystander CPR.

Animals↗
PubMed1992

Oxygenation and ventilation during cardiopulmonary resuscitation utilizing continuous oxygen delivery via a modified pharyngeal-tracheal lumened airway.

Use of continuous transtracheal oxygen delivery systems combined with rhythmic chest compressions can provide excellent oxygenation and ventilation during cardiopulmonary resuscitation. However, occasional displacement of the transtracheal catheter results in life-threatening pneumomediastinal complications. We investigated using the pharyngeal lumen of a pharyngeal-tracheal lumened airway (PtL) as an alternative delivery system for continuous oxygen flow in 21 large mongrel dogs. Excellent ventilation was possible in anesthetized, apneic, and paralyzed dogs in normal sinus rhythm from the "bellows" effect of chest compressions. The hypercapnia and respiratory acidemia resulting from 5 min of complete apnea in ten dogs during normal sinus rhythm was readily corrected (p less than 0.01). In an additional 11 dogs, external chest compressions were performed and oxygen was delivered continuously via the PtL during 20 min of ventricular fibrillation. During this period of cardiac arrest, pH declined (7.38 +/- 0.01 vs 7.19 +/- 0.02; p less than 0.01), but PaCO2 (35 +/- 1 vs 38 +/- 3 mm Hg) and PaO2 (67 +/- 2 vs 68 +/- 3 mm Hg) were not significantly different from prearrest values. Successful resuscitation was achieved in 8 of 11 (73 percent) animals, which is similar to the results in historical controls with endotracheal intubation. No pneumomediastinal complications were seen with use of the PtL. We conclude that using the pharyngeal lumen of the PtL for continuous delivery of oxygen combined with external chest compressions can provide a safe and effective mode of oxygenation and ventilation during cardiac arrest.

Animals↗
PubMed1991

Transformation of Corynebacterium pseudotuberculosis by electroporation.

Corynebacterium pseudotuberculosis was transformed by electroporation, using pNG2, an erythromycin-resistance plasmid from C diphtheriae. Corynebacterium pseudotuberculosis cultivated in brain-heart infusion broth was washed 3 times with water, and resuspended to a final concentration of about 5 x 10(13) colony-forming units/ml. An electroporator constructed in our laboratory incorporated an electrode with 0.8-mm interelectrode gap, using disposable spectrophotometer cuvettes as containers for electroporation. The pNG2 was prepared in Escherichia coli and 4 to 16 micrograms of pNG2 DNA was mixed with 400-microliters amounts of cell suspension in prechilled cuvettes. After incubation on ice for 5 to 10 minutes, the mixture was electroporated at field strengths of up to 18 kV/cm, mixed with 1.5 ml of brain-heart infusion broth, and incubated at 37 C for 2 hours with agitation. Aliquots were then plated on brain-heart infusion blood agar with 15 micrograms of erythromycin/ml. Corynebacterium pseudotuberculosis was transformed at a maximal efficiency of approximately 4 x 10(4) transformants/micrograms of pNG2 DNA. Most total transformants and most transformants per microgram of pNG2 were generated at a field strength of 18 kV/cm. When the concentration of pNG2 DNA was varied, the average total number of transformants increased through a concentration of 30 micrograms/ml, but the efficiency of transformation was highest at the lowest DNA concentration. Transformants contained unmodified pNG2.

Animals↗
PubMed1985

Experimentally induced pneumonic pasteurellosis: dose-response relationships and protection against natural reinfection in calves.

Calves were inoculated intranasally with 2 X 10(6.2) tissue culture infective doses of infectious bovine rhinotracheitis virus, followed in 7 days by intratracheal inoculations with 1 of 4 challenge doses of pathogenic Pasteurella haemolytica. Severity and duration of the ensuing clinical signs of respiratory tract disease were correlated with the challenge dose of bacteria. Calves given 1 X 10(6) colony-forming units (CFU) of bacteria did not develop reliable clinical evidence of disease, whereas those given 1 X 10(8) CFU or 1 X 10(10) CFU of bacteria developed clinical signs of pneumonic pasteurellosis within 12 to 24 hours of bacterial challenge. Severity of clinical signs was equal at the 10(8) and 10(10) doses of bacteria, but duration of clinical signs was greater in calves given the 10(10) dose. Calves given 1 X 10(12) CFU of bacteria developed relatively severe respiratory tract disease in excess of what was necessary for positive clinical detection. Positive correlations were found between the bacterial challenge dose and the height and duration of increased rectal temperature, amount and duration of increases in ocular and nasal discharges, and the subjective evaluation of depressed attitude and appetite. Correlations were not found between challenge dose and respiratory rate or character, or between challenge dose and complete blood cell count. Convalescent calves were resistant to naturally occurring pneumonic pasteurellosis, which caused severe disease in nontreated calves. Adverse effects of P haemolytica were not observed after the first 4 to 15 days after bacterial administration; however, the bacteria were isolated from nasal secretions of convalescent calves 89 to 116 days after bacterial inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

In vivo cross-reactivity of Taenia saginata and Taenia crassiceps antigens in bovine cysticercosis.

Steers sensitized or infected with Taenia saginata exhibited similar delayed-type dermal hypersensitivity (DTH) responses after intradermal inoculation with T. saginata or T. crassiceps skin test antigens. Steers sensitized to T. crassiceps cysticerci exhibited similar DTH responses to intradermal inoculation with T. crassiceps, T. saginata whole worm and T. saginata cysticerci antigens. No correlation existed between the DTH responses and the number of cysticerci in the carcasses. One sensitized/infected and one infected steer harbored cysticerci but exhibited no DTH responses. Infection with cysticerci did not elevate DTH responsiveness in sensitized animals.

Animals↗
PubMed1977

Cardiac Arrhythmias in the horse.

Electrocardiograms were obtained from normal horses and from horses with cardiac or other organic disease that affected the cardiac rhythm. Tracings were obtained from a base-apex bipolar monitor lead, with the negative electrode attached to the skin in the right jugular furrow and the positive electrode attached to the skin on the ventral medline, beneath the apex of the heart. Each arrhythmia was discussed relative to importance and probable cause.

Animals↗
PubMed1976

General anesthesia with methoxyflurane given intravenously to the dog.

Dogs were anesthetized with liquid methoxyflurane administered intravenously by gaseous diffusion through sealed medical grade silicone rubber tubing placed in the femoral vein. A similar catheter placed in the other femoral vein and connected to a pressure transducer measured the increase in intraluminal pressure due to methoxyflurane diffusion into the 2nd catheter from the bloodstream 20 seconds after the catheter was flushed with room air. These pressures were plotted against venous blood methoxyflurane concentration, as determined by gas chromatography, for increasing lengths of anesthetic-administering catheter exposed to the bloodstream.

Anesthesia, Intravenous↗
PubMed1975

Anomalous pulmonary venous return in a Great Dane.

A five-month-old male Great Dane dog was clinically diagnosed as having a complex cardiac anomaly, including anomalous drainage of pulmonary veins. Thoracic radiographs were indicative of this condition, but cineangiocardiography was required for confirmation. At necropsy, examination of the heart revealed that all pulmonary veins entered the right atrium rather than the left atrium as in a normal animal. In addition, a large ostium secundum-type interatrial septal defect and stenosis of the pulmonic valve were demonstrated.

Animals↗