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Biomedical subjects

K McGuinness

Publications and source records attributed to K McGuinness.

10 recordsLinked to original sources
PubMed2004

Portable method for the determination of snoring site by sound analysis.

It has been shown that computerized sound frequency analysis can be used to distinguish between different snoring sites. The aim of this study was to investigate whether a portable recording method using audiotapes and digital minidisc formats could produce waveforms similar to a computer recording. The snores of 12 subjects in their natural sleep were recorded onto audiotape, minidisc and directly onto a computer. For each snorer and recording method 30 snore samples were analysed and their power ratio was calculated indicating the relative amount of sound below and above a set frequency. It was found that the power ratios from audiotape recordings were significantly different to those from computer recordings for all snoring sites (p = 0.0007), whereas there was no significant difference between minidisc and computer recordings (p = 0.41). These results indicate that it would be possible to base a portable snore analysis system for site determination on minidisc, but not on audiotape recordings.

Adult↗
PubMed2002

Sound frequency analysis and the site of snoring in natural and induced sleep.

The aim of this study was to compare the snoring sounds induced during sleep nasendoscopy, and to compare them with those of natural sleep using sound frequency spectra. The snoring of 16 subjects was digitally recorded during natural and induced sleep, noting the site of vibration during sleep nasendoscopy. Patients with palatal snoring during sleep nasendoscopy had a median peak frequency at 137 Hz (118 snore samples). The peak frequency of tongue-base snoring was 1243 Hz (10 snore samples), and simultaneous palate and tongue was 190 Hz (six snore samples). The median power ratios were 7, 0.2 and 5 respectively. The centre frequencies were 371, 1094 and 404 Hz respectively. Epiglottic snores had a peak frequency of 490 Hz (five snore samples). Comparison of the induced (n = 118) and natural (n = 300) snore samples of the 12 palatal snorers showed a significant difference in both the power ratio and centre frequencies (P = 0.031 and P = 0.049). The peak frequency position was similar (P = 0.34). Our results indicate that induced snores contain a higher frequency component of sound, not evident during natural snoring. This is consistent with an element of tongue-base snoring. Although there is good correlation generally, sleep nasendoscopy may not accurately reflect natural snoring.

Endoscopy↗
PubMed1999

State-mandated voluntary newborn human immunodeficiency virus screening in a New York City Hospital.

OBJECTIVE: To report the experience with state-mandated voluntary newborn human immunodeficiency virus (HIV) screening in a large university hospital. METHODS: Retrospective analysis of delivery records and newborn HIV screening data for infants born between May 4, 1996, and January 31, 1997. RESULTS: Of 3111 women, 40% had HIV testing during pregnancy, 28% had testing before pregnancy, 30% never had testing, and 2% gave no information. Most (91%) consented to postpartum newborn HIV testing, although rates varied by HIV counselor (range 81-96%, P < .001) and maternal HIV testing history (range 72-94%, P < .001). Maternal antepartum HIV testing rates varied by delivering physician (range 8-100%, P < .001) and by antepartum care site (clinics, 83%; faculty practices, 72%; private practices, 57%; P < .001). Fourteen HIV-exposed infants (0.46% of infants tested) were identified, 13 of whom were born to women known to be HIV positive before delivery. These women had received zidovudine prophylaxis according to Adult AIDS Clinical Trials Group 076 guidelines. All 14 infants subsequently tested negative for HIV. Human immunodeficiency virus-positive women were more likely than HIV-negative women to have received antepartum care in clinics (93% compared with 11%), have care paid by Medicaid (93% compared with 28%), and reside in high-risk areas (72% compared with 11%) (P < .001). CONCLUSION: Newborn HIV screening has little incremental impact in settings with aggressive antepartum screening and/or low HIV infection rates. Interventions to increase antepartum HIV screening in the private sector should be implemented.

Adult↗
PubMed1995

Genital ulcer disease in women infected with human immunodeficiency virus.

OBJECTIVE: The purpose of this study was to determine the prevalence and microbiologic characteristics of genital ulcer disease in a population of human immunodeficiency virus-infected women. STUDY DESIGN: A retrospective cohort study was performed in university-affiliated, hospital-based women's human immunodeficiency virus clinics. A total of 307 women with human immunodeficiency virus infection were followed up during 20 months. There were no interventions. Age, race, CD4+ cell counts, bacteriologic and virologic analyses in cases of ulcers, serologic testing for syphilis, and histopathologic examination in selected cases (n = 6). RESULTS: Among 307 women followed up over a 20-month period, 43 ulcers were detected with a prevalence of 14%. Among the ulcer cases the average absolute CD4+ lymphocyte number was 210/mm3. Diagnostic evaluation yielded no proven etiologic agent in 26 (60%) of the cases. Twelve of the 43 cases (28%) were positive for herpes simplex-2. Five cases (12%) yielded unusual or mixed bacteriologic types. No cases were attributable to primary syphilis infection. One case each of an ulcer infected with cytomegalovirus, Chlamydia trachomatis, and Gardnerella vaginalis, as well as three unusual presentations of herpetic ulcers, is analyzed in detail. CONCLUSION: These cases exemplify the often dramatic presentation of human immunodeficiency virus-related genital ulcers and the clinical complexity of both diagnosis and management. The frequent lack of an infectious or neoplastic cause in human immunodeficiency virus-infected women with genital ulcer disease suggests that human immunodeficiency virus may play a local role in causation or exacerbation. Biopsies of atypical genital ulcers should be considered to aid diagnosis. Further studies are needed to elucidate the pathogenesis of genital ulcer disease in human immunodeficiency virus-infected women.

AIDS-Related Opportunistic Infections↗
PubMed1995

Practical limitations of the Deltatrac indirect calorimeter.

Indirect calorimetry is used to assess energy requirements. The Deltatrac Metabolic Monitor is a relatively inexpensive indirect calorimeter which uses a 'fixed' flow of ambient air to collect expired air. Only oxygen and carbon dioxide concentrations are measured and the 'fixed flow' is assumed in the calculation of oxygen consumption ((.)VO(2)) and carbon dioxide production ((.)VCO(2)). Using inert gas dilution we have studied the effect on (.)VO(2), and on the variability in (.)VO(2), of changing and lengthening the 1.77 m length of 35 mm tubing supplied with the instrument to collect expired air, and of using a mask to collect expired air instead of the manufacturer's hood. One would anticipate that changing the tubing could cause a change in resistance to gas flow and thus affect the true flow rate. This would alter the gas concentrations seen by the analysers, but the 'fixed flow' would still be assumed so the results would be in error. Adding extra lengths of manufacturers tubing caused an apparent rise in (.)VO(2) of 0.36%/m of tubing added, and using 22 mm tubing instead of the manufacturer's 35 mm tubing increased (.)VO(2) by 0.42% for each 10 cm of tubing added. Using the mask to collect expired air instead of the canopy (.)VO(2) was higher, possibly due to the energy cost of holding the mask, and was more variable, probably because of poorer mixing of the expired air. To measure (.)VO(2) using a mask with the same precision as a 10 min measurement made with the hood would entail measuring (.)VO(2) for 14.5 min. The methods used to collect expired air (mask or canopy, length and type of tubing) when measuring metabolic rate with the Deltatrac do affect the results obtained but these effects are small and predictable.

Journal Article↗
PubMed1985

Dystrophia myotonica and atracurium. A case report.

Atracurium was used to produce neuromuscular blockade in a patient with dystrophia myotonica. Operating conditions were excellent and myotonia was not seen. Sensitivity to atracurium was not seen and spontaneous recovery was not prolonged.

Adult↗
PubMed1985

Induction of anaesthesia with propofol ('Diprivan') or thiopentone and interactions with suxamethonium, atracurium and vecuronium.

A randomized study involving 60 healthy patients was performed to examine the induction characteristics and the possible interactions between propofol 2.5 mg/kg or thiopentone 4 mg/kg and three neuromuscular blocking agents, suxamethonium, atracurium and vecuronium. The time of onset to maximum blockade, the degree of blockade and the duration of blockade were measured using the electromyogram. The response to each muscle relaxant was not significantly different after induction of anaesthesia by propofol or thiopentone. A decrease in arterial blood pressure which occurred after both induction agents was greater after propofol than after thiopentone P less than 0.05. There was no significant difference in the increase in heart rate which occurred after the injection of either propofol or thiopentone.

Adult↗
PubMed1985

Propofol in emulsion form: induction characteristics and venous sequelae.

Propofol in a 1% emulsion was used to induce anaesthesia in 20 female patients premedicated with diazepam (10 mg). A dose of 2.5 mg kg-1 produced a rapid loss of consciousness and only minor excitatory effects. Discomfort during the injection was not severe. Cardiovascular changes included a fall in blood pressure similar to that which occurs with other induction agents, and a decrease in pulse rate. Apnoea occurred after each induction and in some patients (13) was prolonged (greater than 60 s). There were no venous sequelae, and patient acceptance was high. Propofol given in an emulsion to induce anaesthesia merits further study.

Adult↗
PubMedDate not supplied

Technical note: a compact data logger for ambulatory skin temperature measurement.

A miniature, body-worn data logger has been developed for multi-channel recording of small changes in skin surface temperature. The unit has been designed for small size, long battery life and high accuracy together with full programmability and an infra-red (contactless) transfer of parameters and data. Temperature is measured using thermistors with a resolution of 0.005 degrees C and an absolute accuracy of better than 0.05 degrees C. A comprehensive software package running on a laptop PC is used for initial setting of the logger parameters and downloading and displaying the temperature data. The present system records eight channels of temperature at intervals from 30 seconds to 99 minutes. It contains 64 K bytes of non-volatile memory allowing 3274 sets of readings including subject identification, battey status, date and time. The logger size is 55 mm x 31 mm x 9.5 mm and weighs 20 g.

Calibration↗