Search PubMed⌕ Search

Biomedical subjects

A W McCombe

Publications and source records attributed to A W McCombe.

At least 19 recordsLinked to original sources
PubMed1995

Hearing loss and motorcyclists.

Motorcyclists are known to be exposed to excessive wind noise levels when riding. The potential adverse effects of this exposure on their hearing was investigated. Temporary threshold shift (TTS) was assessed by asking 18 riders to undertake a standard test run of one hour at a steady 80 mph, and performing audiometry before and immediately afterwards. Permanent threshold shift (PTS) was assessed by performing pure-tone audiograms on a highly screened group of 246 motorcyclists and comparing their hearing thresholds with those of an appropriate control group obtained from the MRC National Study of Hearing. Significant TTS was found at 0.25, 0.5, 1 and 2 kHz. The greatest TTS occurred at 1 kHz, with a mean hearing loss of 10.3 dB. The hearing thresholds of the motorcyclists were significantly worse than the controls at 0.25, 0.5, 1 and 2 kHz, and was most marked at 0.5 and 1 kHz where their hearing loss (PTS) was, respectively, 3.7 and 3.6 dB greater than expected. These findings demonstrate evidence of both temporary and permanent hearing loss from motorcycling and present a strong argument for the need for some form of remedial action.

Adolescent↗
PubMed1995

An acoustic screening test for obstructive sleep apnoea.

Third-octave sound analysis was performed on the snoring sounds of nine subjects with obstructive sleep apnoea (OSA) and 18 with simple snoring. Both groups demonstrated a large low frequency peak in linear sound levels at around 80 Hz. However, the OSA group displayed a substantially larger high frequency sound component. We utilized this fact in the development of an acoustic index (Hawke Index: HI) which describes the ratio between the overall A-weighted and linear sound levels for the recorded snoring sound of each subject [HI = dB(A)/dB(SPL) for Lmax]. There was a significant positive correlation between the apnoea/hypopnoea index and the HI (r = 0.73, t = 5.3, 25df, P < 0.001). If a value of 0.90 or greater was taken as diagnostic of OSA, the HI exhibited 67% sensitivity, 100% specificity, 100% positive and 86% negative predictive accuracy. With further development, we believe this acoustic phenomena may have a role as a screening test in the diagnosis of OSA.

Acoustics↗
PubMed1994

Two solutions to the problem of noise exposure for motorcyclists.

Two solutions to the problem of excessive noise exposure and consequent hearing loss in motorcyclists were investigated and are described. One was an antecedent behaviour-modifying 'prompting' strategy, where a set of earplugs and an advice sheet were provided at the point of sale to consecutive purchasers of new motorcycle crash helmets. Forty-eight riders were recruited but data for analysis were only available in 41. The earplug usage rate was significantly increased from 27% to 83% by this intervention. The second solution involves various aerodynamics and sound-proofing helmet modifications made in an effort to reduce interior noise levels. The only modification which achieved a significant reduction from previously reported average sound levels was the incorporation of a pair of 'standard' earmuffs under the helmet shell. This gave noise levels of 84 dB(A) at 22 m/s (50 mph) and 93 dB(A) at 36 m/s (80 mph), compared to known average values of 95 dB(A) and 107 dB(A), respectively. Both solutions are eminently feasible and desirable, and we hope that the motorcycle industry will act on them.

Adult↗
PubMed1994

Hearing loss in Grand Prix motorcyclists: occupational hazard or sports injury?

The prevalence of noise-induced hearing loss (NIHL) in current motorcycle grand prix racers was investigated. A total of 44 riders was randomly recruited and underwent interview, otological examination and pure tone audiometry. The median age was 28 (range 18-37) years and median racing experience was 10 (range 2-21) years. Twenty riders (45%) had hearing losses greater than expected for age matched controls. Not surprisingly this hearing deficit tended to increase with racing experience (r = 0.5, t = 2.51, 19 d.f., P < 0.05). Only 17 riders (39%) were regular users of earplugs and only nine had used them for most of their racing careers. There is a need to raise awareness to this problem and increase the use of earplugs to avoid NIHL in grand prix motorcyclists.

Acoustic Impedance Tests↗
PubMed1994

How I do it: stapling of pharyngeal pouch.

The last 10 years have seen an explosion in endoscopic and minimally invasive surgical techniques. The principle of minimally invasive surgery is the treatment of the disease or condition with minimal upset to the surrounding tissues and the patient. Instrument technology has kept abreast of this, and many new suturing (stapling) devices have been developed to aid these procedures. We present a technique for the treatment of pharyngeal pouches that encompasses this philosophy.

Endoscopy↗
PubMed1993

Radiotherapy and complications of laryngectomy.

In an effort to establish factors responsible for our post laryngectomy fistulae we reviewed 357 patients who underwent total laryngectomy between 1965 and 1990, for laryngeal carcinoma. Pharyngocutaneous fistulae occurred in 84 cases (23 per cent). There was no difference between the fistula group and the non-fistula group with regard to age, sex, general condition, or tumour differentiation. The only significant, positive association was with previous radical radiotherapy (10 fistulae out of 167 primary laryngectomies (4 per cent) versus 74 fistulae out of 190 salvage laryngectomies (39 per cent)). The median time to occurrence of a fistula was day seven in both groups. However, in the non-radiotherapy group the median duration of the fistula was 28 days; the majority healing spontaneously, with only one patient requiring surgical closure. There were no 'hospital' deaths. In the radiotherapy group the median duration of fistulae was 112 days with 30 patients requiring a total of 66 procedures to achieve closure of the fistula. There were six 'hospital' deaths in this group. We conclude that previous radical radiotherapy strongly predisposes towards the occurrence of a post-laryngectomy fistula. Fistulae in this group tend to be longer lasting and are more likely to require surgical repair.

Combined Modality Therapy↗
PubMed1993

Laser treatment of rhinitis--1 year follow-up.

Laser cautery of the inferior turbinates for the treatment of rhinitis has been shown to be as effective as sub-mucosal diathermy in the short-term and to produce less morbidity. However, the long-term effects are unknown. A cohort of patients who were treated by either of these methods were reviewed 1 year after treatment. Subjective and objective measurements of airway obstruction were performed using a linear analogue scale and a nasal peak inspiratory flowmeter. The results obtained were compared with those recorded pre-operatively, 3 days post-operatively and 6 days post-operatively. In contrast to the results of sub-mucous diathermy of the inferior turbinates for the treatment of rhinitis, the reduction in subjective nasal airway obstruction obtained by laser cautery to the inferior turbinates is maintained 1 year after surgery. Neither method of turbinate reduction was associated with a sustained objective improvement in nasal airway patency as measured by peak nasal inspiratory flow rate determinations.

Adolescent↗
PubMed1993

Warning signal detection and the acoustic environment of the motorcyclist.

A two-part study was undertaken to investigate warning signal detection by motorcyclists. First the acoustic environment was established for both the helmeted and bareheaded rider between speeds of 0 and 100 mph. For the helmeted rider it was found that below 20 mph vehicle noise was dominant and between 20 and 40 mph there was a variable contribution from both vehicle and wind noise. At 40 mph wind noise became the dominant sound source and increased linearly with the log10 of speed from 90 dB(A) to reach 112 dB(A) at 100 mph. Sound levels were consistently 18 dB(A) greater for the bareheaded rider once above 10 mph, and followed a similar pattern. Recordings of these sounds were sampled into an Amiga computer. Suitable sound combinations were played back at levels appropriate to speed to recreate the rider's acoustic environment at differing speeds. The minimum detection level (MDL) of four traffic warning signals was then measured in 19 normal hearing subjects for three test conditions: no helmet, helmet and helmet with earplugs. The MDL for all warning signals was lowest with a crash helmet in place for sound levels equivalent to speeds of 30 mph or less. The addition of earplugs led to significant reductions in MDLs at sound levels equivalent to speeds of 40 mph, or greater. Signal detection was poorest at all speeds greater than 0 mph, when bareheaded. We would conclude that earplugs are not required for motorcyclists in the urban environment.(ABSTRACT TRUNCATED AT 250 WORDS)

Accident Prevention↗
PubMed1992

Managing swabs in the operating theatre: a new method.

The swab count has traditionally used a swab rack. A new alternative 'bag' method involves placing used swabs in batches of five into plastic bags which are sealed and stored in a bin. A randomized prospective study was carried out to compare these two methods. Twenty consecutive ear, nose and throat cases were randomized to rack or bag collection. Swab-related activities were divided into three categories and analysed by formal time-and-motion criteria. Blood contamination of operating theatre and circulating personnel was recorded. The time involved in all three swab-related activities was significantly less using the bag technique. There was no theatre blood contamination using this method, but significant contamination occurred using the rack. Circulating theatre personnel were minimally contaminated in two cases using the bag method but were grossly contaminated in all ten cases using the rack method. The bag technique is therefore safe and time efficient.

Equipment Contamination↗
PubMed1992

A comparison of laser cautery and sub-mucosal diathermy for rhinitis.

A randomized prospective trial was conducted to compare the efficacy of laser cautery against sub-mucosal diathermy to the inferior turbinates in 29 patients with rhinitis. Laser diathermy was performed using an arthroscopic fitment to a CO2 laser. Subjective and objective measurement of airway obstruction were performed, using a linear analogue scale and a nasal peak inspiratory flow meter, before operation and at 3 days and 6 weeks afterwards. In both groups there was a similar and significant improvement in subjective scores at 6 weeks (SMD from 3.6 to 1.8, P less than 0.01; laser from 3.9 to 2.1, P less than 0.001), but only the laser group was significantly better at Day 3 (SMD from 3.6 to 3.5, n.s.; laser from 3.9 to 3.0, P less than 0.05). In addition, there was significantly more general subjective morbidity at Day 3 in the SMD group (P less than 0.01). The objective scores improved equally in both groups but were not significant. We conclude that laser cautery of the inferior turbinate is a superior alternative to SMD for the treatment of rhinitis.

Adult↗
PubMed1991

Meningitis from canine Pasteurella multocida following mastoidectomy.

A case of Pasteurella multocida meningitis, following a mastoidectomy is presented. The association of close contact with pets, many of which harbour Pasteurella multocida as part of their normal buccal flora. This case confirms the potential benefit of taking an ear swab prior to mastoid surgery and in seeking an appropriate 'pet' history.

Adult↗