The Ramathibodi nasal filter in a simulated human airway: evaluated with laser smoke particles and a laser diode dust portable monitor.

The Ramathibodi nasal filter was specially designed as a personal respiratory protective device. It was attached to a simulated human airway composed of a nasal and pharyngeal model, airway passage and lung model machine. The system was run in a laser smoke particles environment. The laser smoke particles with suspended particulate matter size of less than 15, 10 and 2.5 microns (PM15, PM10 and PM2.5) were selected. The amount of each particle size in the simulated human airway with and without the Ramathibodi nasal filter was measured continuously by a laser diode portable dust monitor. One hundred sample sizes were analyzed by a descriptive statistical method at the Department of Otolaryngology, Ramathibodi Hospital from January to November 1999. The graphic distribution patterns of each residual particle size in the simulated human airway with and without the Ramathibodi nasal filter were compared. The filtration efficacy of the Ramathibodi nasal filter should be tested further by this experimental model. The device could be applied intermittently in adult nasal vestibules.

CO2 laser surgery in otorhinolaryngology-site and complications: a 10-year experience at Ramathibodi Hospital.

OBJECTIVE: To present data on ten years' experience in CO2 laser surgery and associated complications among otorhinolayngologic patients. MATERIAL AND METHOD: The study involved examining records of otorhinolaryngologic patients who underwent CO2 laser operations during a 10-year period (July 1, 1986-June 30, 1996). The sample consisted of 733 patients: 370 male and 363 female patients. CO2 laser surgery in otorhinolaryngology was first used in Ramathibodi Hospital on July 10, 1986. RESULTS: These patients were aged 2 months to 93 years with the mean age of 24.3 years (median = 16 years). Among 1,725 operations, 1,570 operations (91%) were performed under general anesthesia and 155 operations (9%) were performed under local anesthesia. In our series, the most frequent sites for laser surgery were as follows: larynx (77.22%), oral cavity and oropharynx (12.64%), skin (5.04%) and nose and paranasal sinuses (3.31%). Intraoperative complications occurred in 18 out of 1,725 (intra-operative complication rate of 1%). Laser-related complications were found in 13 out of 1,725 operations (0.75%) and non laser-related complications were found in 5 out of 1,725 operations (0.25%). There was no mortality. CONCLUSION: CO2 laser is a useful modality of treatment in otorhinolaryngologic surgery especially in the larynx. Our experience demonstrates the relative low incidence of complications (1%) and no mortality in otorhinolaryngology head and neck surgery.

Efficacy of intranasal stent with filters for different laser smoke particle concentration.

Intranasal, hollow, cylindrical, medical grade, silicone stent with two layers and one layer of half face mask outer filter at each end was tested with different concentrations of laser smoke particles. A single pulse mode of carbon dioxide laser smoke particle created suitable polydisperse atmospheric suspended particulate matter amount. The personal respiratory protective device efficacy was done at the Otolaryngology Department, Ramathibodi Hospital from July to September 1998. The Whatman filter had the same laser smoke particle amount that passed through each filter of the intranasal stent. The cyclical air flow rate of 2 l/min in the nasal model was controlled by a lung model machine and respirometer. The particle deposition in filter materials was counted under a high power optical microscope. The filtration efficacy of an intranasal stent with filters for 5, 10 and 20 shots of laser smoke particle were 90.5, 94.6 and 95.6 per cent respectively with a mean of 93.6 per cent. The device application in a human nasal vestibule depended on acceptable nasal air flow resistant in various highly air-polluted areas.

Nasal model and lung model machine for intranasal stent with filters efficacy evaluation.

Nasal model and lung model machine simulated human respiratory situation with cyclical air flow rate of 2 1/min. They were used to evaluate filtration efficacy of filters in an intranasal stent for laser smoke particles in the Otolaryngology Department, Ramathibodi Hospital from February to June 1998. The filters were three layers of half face mask outer filters. Each of five sets or 10 intranasal stents with filters or Whatman filters was attached at both inlet ends of the nasal model. A Whatman filter collected the maximum particle amount from 10 shots, 10 W and 0.2 s of single pulse mode carbon dioxide laser evaporative field for 5 min which was the same amount passed through filters of the intranasal stent. A high power optical microscope was used to count particle retention in each filter. The mean filtration efficacy of filters in the intranasal stent was 94.4 per cent when compared with that of the Whatman filter. A personal respiratory protective device could be applied in the human nasal vestibule to prevent polydisperse suspended particulate matter in a highly air-polluted area. The nasal model with lung model machine should be tested under different concentrations of laser smoke particles or at the main roadside.

Personal respiratory protective devices: efficacy of Millipore and Whatman filters.

A Millipore filter with 0.22 micron pore size and a Whatman grade 1 filter with > 11 microns particle retention were used to capture laser smoke particle mimic atmospheric suspended particulate matter. The experiment was conducted at the Department of Otolaryngology in Ramathibodi Hospital from April 1996 to October 1997. The laser smoke particle evacuator with rotameter created an air flow rate of 15 l/min through the filters. The mean and standard deviation of the laser smoke particle count under high power optical microscope in a 10 Millipore filter and a 10 Whatman filter were 411,327.6 +/- 13,325.0 and 290,453.0 +/- 28,409.8 respectively, 29.4 per cent different. Laser smoke particle size distribution in both filters under eyepiece micrometer was: 1 to 10 microns in Millipore (99.0%) and in Whatman (96.2%), 1 to 5 microns in Millipore (77.1%) and in Whatman (77.6%), no laser smoke particle larger than 17 microns was detected. The Millipore filter ruptured when the air flow rate was greater than 15 l/min. The Whatman filter was suitable for evaluating filtration efficacy of various personal respiratory protective devices in a high air flow rate condition.

Personal respiratory protective devices: efficacy of intranasal stent with filters.

Intranasal, hollow, cylindrical, medical grade and silicone stent with two outer layers face mask filters at both ends was proposed for atmospheric suspended particulate matter prevention. The personal respiratory protective device efficacy was done at the Otolaryngology Department, Ramathibodi Hospital from April 1996 to October 1997. Single pulse mode of carbon dioxide laser smoke particle was the suitable source of atmospheric suspended particulate matter. A laser plume evacuator removed laser smoke particles with 5 Millipore filters of 0.22 um pore size or 5 intranasal stent with filters attached at the inlet end. A Millipore filter got the same laser smoke particle amount that passed through each intranasal stent filter with an air flow rate of 15 l/min controlled by a rotameter. Laser smoke particle deposition in filter materials was counted under a high power optical microscope. Laser smoke particle amount in each layer of a four-layer filter of intranasal stent with 7.5, 15.0 and 30.0 l/min air flow rates is shown. The filtration efficacy of four, three and two layers of intranasal stent with a filter for laser smoke particle retention were compared. An intranasal stent with filter could be applied in a human nasal vestibule with acceptable air flow resistant during public transportation in a traffic congested area.

Experiment of intranasal synthetic filter for prevention of suspended particulated matter: rhinomanometric evaluation.

The experimental study of intranasal synthetic filter with stent was tried to decrease suspended particulate matter for human respiratory tract. Facial mask or surgical mask were evaluated. Nasal vestibular size in Thai adults was estimated. Different kinds of stents and filters were used. Standard anterior rhinomanometry was the proper objective method to test nasal air flow resistant of stent and filter. Nasal obstructive symptom correlated well with rhinomanometric results. One layer of outer and inner face mask at each end of the cylindrical silicone stent was the suitable device. There were no complications or side effects. This personal protective device was cheap and available. The filtration efficacy should be tested in a general population during a highly air-polluted period.

Pseudocyst mass at neck: complication after tracheostomy.

Neck mass after the tracheostomy is a rare complication. A case report of pseudocyst at the left paratracheal area was presented and this has not yet been reported in the English literature. We proposed the pathophysiology of this condition and prevention methods.