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Biomedical subjects

D John Doyle

Publications and source records attributed to D John Doyle.

12 recordsLinked to original sources
PubMed2002

Silica zeolite scavenging of exhaled isoflurane: a preliminary report.

PURPOSE: We evaluate the effectiveness of a silica zeolite (Deltazite) hydrophobic molecular sieve adsorbent, in removing exhaled isoflurane. METHODS: In three experiments, a simulated anesthesia mannequin was ventilated using 1% isoflurane in nitrous oxide and oxygen (1:1 ratio) at a gas flow of 3 L x min-1. Airway pressures, end-tidal carbon dioxide [ETCO2], inspired and end-tidal isoflurane were measured. The scavenging line was connected to a canister containing 750 g of the silica zeolite. Concentrations of isoflurane entering and exiting the canister were measured, as well as the pressure gradient across the canister and gas flow through the canister. In phase 1 (n = 3), the mannequin was ventilated for 6.5 hr, followed by phase 2 where a test lung replaced the simulator. The time (phase 1 plus phase 2) until isoflurane 'breakthrough' (> 0.02%) was noted. RESULTS: The average canister weight increase was 68 g, however 92 g of isoflurane were used. The isoflurane concentration exiting the canister remained undetectable throughout phase 1 in each experiment. The pressure gradient across the canister averaged 0.13 cm H2O and did not increase throughout phase 1. The time to 'breakthrough' (phase 1 plus phase 2) was 8.0 hr, 8.8 hr and 9.0 hr. CONCLUSIONS: Silica zeolite was effective at completely removing 1% isoflurane from exhaled gases for periods of eight hours. The technology shows promise in removing isoflurane emitted from anesthesia machine scavenging systems.

Adsorption↗
PubMed2002

Upper airway diseases and airway management: a synopsis.

This article summarizes some of the more important upper airway conditions likely to affect airway management. A number of upper airway conditions may present difficult challenges to the anesthesiologist. For instance, infected airway structures may lead to partial airway obstruction, stridor, or even complete airway obstruction. Partial airway obstruction may be mild, as in snoring or nasal congestion, or may be more severe, perhaps requiring the use of airway adjuncts, such as a nasopharyngeal airway. Complete airway obstruction is usually managed by prompt intubation, but surgical airways are sometimes needed as a last resort.

Anesthesia↗
PubMedDate not supplied

Blood transfusions and the Jehovah's Witness patient.

This paper provides a brief history of the evolution of the Jehovah's Witness faith with a short discussion on the biblical justification for followers' refusal of blood transfusions. It also briefly considers the ethical principles leading to potential conflicts between health care workers and Jehovah's Witnesses patients and examines several significant legal rulings in the United States and Canada that caregivers should be aware of. A discussion of what blood products are and are not currently acceptable is also presented. Finally, the impact of the Jehovah's Witness reform movement aimed at allowing blood transfusions and the nature of recent doctrinal shifts in the Jehovah's Witness faith on the matter of blood transfusions are discussed.

Blood Transfusion↗
PubMedDate not supplied

Monitoring hemodialysis vascular access by digital phonoangiography.

We are intrigued by the possibility of using digital spectral analysis to detect hemodialysis vascular access stenosis. Such a monitor could be inexpensive, noninvasive, and portable enough to allow continuous monitoring. This report suggests how individuals wishing to conduct such research can use a simple but effective transducer design we have employed, how the data so obtained can be analyzed in the time and frequency domains using inexpensive digital signal processing software available via the Internet, and how data recordings might be shared via the Internet to facilitate collaboration.

Arteriovenous Shunt, Surgical↗