American Standards Association Research Articles

Determinants of difficult laryngoscopy based on upper airway indicators: a prospective observational study

BackgroundThe main cause of anesthesia-related deaths is the failure to manage difficult airways. Difficult laryngoscopic exposure is a major cause of unsuccessful management of difficult airways. Inadequate preoperative airway assessment hinders the clinical management of difficult airways cases, emphasizing the critical need for accurate identification of difficult airways. Currently, no definitive and reliable indicators are available to predict a difficult airway. Our study aims to predict laryngoscope exposure risk factors by combining ultrasonically measured upper airway anatomic parameters with physical examination indicators.MethodsPatients aged 18 to 75 years, classified as American Standards Association (ASA) I-III, and scheduled for elective general anesthesia with endotracheal intubation were included. All patients received the upper airway and ultrasonographic measurements. After anesthesia induction, laryngoscope exposure was analyzed using the Cormack-Lehane grading system, with Grades III and IV as indicative of difficult laryngoscopy. Univariate and multivariate logistic regression analyses were performed to identify reliable indicators for predicting difficult laryngoscopy. Receiver Operating Characteristic (ROC) curve analysis was utilized to assess the predictive performance of each indicator.ResultsA total of 1120 patients finished the study, with 710 cases found in Grade I laryngoscopic exposure group, 360 cases in Grade II group, and 50 cases in Grade III group. There was no case observed in Grade IV group, thereby resulting in an incidence of difficult laryngoscopy of 4.46%. Univariate logistic regression analysis revealed that several parameters including age, Body Mass Index (BMI), neck circumference, neck mobility, snoring intensity, as well as ultrasound measurements of the pre-epiglottic space and thyromental distance were identified as significant risk factors for difficult laryngoscopy (P < 0.05). Among these, BMI, and neck circumference exhibited notable predictive value, with Area Under The Curve (AUC) values of 0.746 (95%CI 0.649–0.842) and 0.732 (95%CI 0.638–0.827), respectively. Neck mobility was also identified as an independent risk factor for predicting difficult laryngoscopy (P = 0.009) in multivariate logistic regression analysis, with an AUC of 0.672 (0.562–0.782) in the ROC curve.ConclusionsOur findings revealed a direct correlation between difficult laryngoscopy and age, BMI, neck circumference, neck mobility, snoring intensity, as well as ultrasound measurements of the pre-epiglottic space and thyromental distance. Furthermore, neck mobility was identified as an independent predictive factor.Trial registrationThe trial was registered prior to patient enrollment at clinicaltrials.gov (register no. ChiCTR2100053826, Date of registration: November 30, 2021).

American Standards Association

American Standards Association

Radio Interference is Problem of New American Standards Association (ASA) Coordination Committee

Radio Interference is Problem of New American Standards Association (ASA) Coordination Committee

New perspectives to use Munsell color charts with electronic devices

This article considers the evolution of the use of the Munsell system for assessing soil color. In the 1920s, Munsell color disks were recommended for soil color measurement. Munsell soil color charts (MSCs) were introduced in the 1940s. In 1942, the American Standards Association recommended that spectrophotometers be used for quantitative measurements and the Munsell system be used only for the psychological characterization of color. Despite this recommendation, soil scientists have continued using MSCs to measure soil color semi-quantitatively.The utility of MSCs for color determination depends on three qualities: ambiguity, adequacy and reliability. Quantitative color was measured with a spectrophotometer. Chip colors were compared using the CIELAB color difference (ΔEab∗). To examine ambiguity, we calculated the ΔEab∗ for every possible MSC color chip pair. Considerable ambiguity was found; 60% of the chips had duplicates. Chips were considered duplicates if the color difference was barely perceptible visually (ΔEab∗ < 3).To investigate adequacy, the color difference between 161 soil samples and their closest MSC chips was calculated. Only 52% of the samples had ΔEab∗ < 3. This indicated that the color range of the MSC does not adequately cover the range of natural soil colors.To study the reliability of MSCs, an old and a new MSC were compared. The identically designated chips in the old and new MSC generally had color differences of less than 3. Only 16% had ΔEab∗ > 3. In addition, chips within a chart or even within a sheet can fade over time in a non-uniform way. On the 2.5Y sheet, a stable group of color chips (∼63%) occurred. This stable group consisted of the chips that were the least prone to discoloration (ΔEab∗ < 3).This study determined that the inadequacy and ambiguity of MSCs can be overcome by using MSCs in combination with flatbed scanners. MSCs can be used to calibrate flatbed scanners for the purpose of soil color measurement. A procedure is proposed. The procedure calibrates the scanner using 7 chips from the stable group of the 2.5Y sheet. This procedure enables the measurement of soil color inexpensively and efficiently. The high efficiency of the method was confirmed by testing the accuracy of the soil color determinations for 20 soil samples, covering a wide color range. The calibration procedure quadruples the precision of color estimation compared to solely using MSCs and results in soil color measurements close to those achievable with spectrophotometers.

Risk factors of perioperative complications for posterior spinal fusion in degenerative scoliosis patients: a retrospective study

BackgroundsRare study has been conducted to detect risk factors of perioperative complications, which are closely related to preoperative status of the patients and surgical stress. The aim of this study is to detect these relationships in degenerative scoliosis (DS) patients.MethodsPerioperative complications of 226 cases with DS (56 males and 170 females; 65.5 ± 8.1 years old), who accepted posterior fusion in our hospital from January, 2013 to July, 2017, were retrospectively reviewed. Potential risk factors were first compared between patients with or without perioperative complications using student t test or Chi-squared test. Then, the unevenly distributed variables between the two groups were analyzed with binary logistic regression model.ResultsAll patients separately underwent decompression with short limited instrumentation (116, 51.3%) or with long instrumentation for correction (110, 48.7%). The mean operation duration (OD) was 216.9 ± 64.2 min and the average amount of bleeding was 587.4 ± 357.2 ml. 44 cases (19.5%)suffered from the complications during the perioperative phase, including incision complications (5.3%), urinary infection (3.5%), dura tears/cerebrospinal fluid (CSF) leakages (3.5%) and new neurological deficits (2.7%). Hospital stay was significantly extended for the complications (p < 0.001). Univariate analysis showed that OD (p < 0.001), bleeding (p = 0.014), American Standards Association (ASA) grade > 2 (p = 0.011) and RBC transfusion≥4 U(p = 0.028) were associated with these complications. Multivariate logistic regressions revealed that only ASA grade > 2(p = 0.011, Odds Ratio[OR] = 4.104, 95% Confidence Interval[CI] = 1.413~ 11.917) and OD (p = 0.013, OR = 2.697, 95% CI = 1.233~ 5.899) were the independent risk factors.ConclusionsThe high morbidity of perioperative complications for posterior spinal fusion would significantly extend hospital stay of DS patients. It was independently related to higher ASA grade and longer OD.

History of the sound level meter in standards

In 1932, the Acoustical Society of America started work on the first American Standards Association standard for sound level meters. The purpose was to create a set of standards for sound level meters “such that, if a given noise of a general character is measured with any meter designed in accordance with the standards, the result will be substantially the same as that which would be obtained with any other similarly designed meter.” The standard that resulted, Z 24.3 1936 was the first of many that trace the development of the sound level meter over the past 86 years. This paper follows the history and development of the sound level meter in the original American Standards Association and subsequent American National Standards Institute standards: Z 24.3 1944, S1.4 1961, S1.4 1971, 1.4 1983, and S1.4 2014. During that time the sound level meter has shrunk from a more than 100 pound, vacuum tube machine to a modern the modern, lightweight meter. The standard, however, has grown from a mere 11 pages in 1936 to 50 pages in 2014.

Critical Incident Reported in an Obstetric Unit of a Tertiary Care Hospital of a Developing Country, over a Period of Two Years

Introduction: A lot of literature is available on critical incidents and near misses but specialty based critical incidents are very scanty. Aim: In this audit, we aimed to report critical incident and near misses during conduct of obstetric anesthesia over a period of two years. Methodology: Critical incident forms were collected, entered, analyzed and categorized on the basis of American Standards Association (ASA), phase of incidents, system involved, and type of errors, outcome and action taken. Human error was further categorized on the basis of their contributing factor marked in form. Results: During the reporting period, 5511 anaesthetics were administered and 55 reports were received out of which 53 reports were included in analysis. Fifty three reports were divided into 33 critical incidents and 20 near misses. Out of 33 critical incidents, 54.5% involved CVS system and musculoskeletal system, followed by neuromuscular (n = 5), drug related (n = 4), airway/respiratory system (n = 2), central nervous system (n = 2) and renal system (n = 1). Forty five incidents possess no untoward effect while 7 led to minor and only one to severe physiological disturbance. Human errors were (n = 30) 57% reports and failure to check was the main contributory factor. Conclusion: Critical incidents reporting needs to be introduced in sub-specialties at departmental, national and international level. Checking of equipment, medication and anesthesia machine must be part of regular checks in elective and emergency cases.

Erratum to: Investigation of one-lung ventilation postoperative cognitive dysfunction and regional cerebral oxygen saturation relations.

The original version of this article unfortunately contained a mistake. In "Abstract" and the 1st para-graph of Section 2.1, the full name of the abbreviation "ASA" was incorrect in "American Standards Association (ASA)". The correct version should be "American Society of Anesthesiologists (ASA)".

Investigation of one-lung ventilation postoperative cognitive dysfunction and regional cerebral oxygen saturation relations.

To explore the relationship of postoperative cognitive dysfunction (POCD) in one-lung ventilation (OLV) patients and regional cerebral oxygen saturation (rSO2). Twenty-nine male and twenty-one female cases of OLV received thoracic surgery, with American Standards Association (ASA) physical status being at Grades I-III. Neuropsychological tests were performed on the day before operation and 7 d after operation, and there was an intraoperative continuous monitoring of rSO2. The values of rSO2 before anesthesia induction (t1), at the beginning of OLV (t2), and at the time of OLV 30 min (t3), OLV 60 min (t4), the end of OLV (t5), and the end of surgery (t6) were recorded. The intraoperative average of rSO2 , the intraoperative minimum value of rSO2 (rSO(2, min)), and the reduced maximum percentage of rSO2 (rSO(2, %max)) when compared with the baseline value were calculated. The volume of blood loss, urine output, and the amount of fluid infusion was recorded. A total of 14 patients (28%) in the 50 cases suffered from POCD. The values of mini-mental state examination (MMSE), the digit span and the digit symbol on the 7th day after the operation for POCD in OLV patients were found to be significantly lower than those before the operation (P<0.05). The values of MMSE and vocabulary fluency scores were significantly lower than those in the non-POCD group (P<0.05). The values of rSO2 in the POCD group of OLV patients at t2 and t3 and the values of rSO2 in the non-POCD group at t2 were found to be significantly higher than those at t1 (P<0.05). The values of rSO(2, %max) in the POCD group were significantly higher than those in the non-POCD group (P<0.05). When the value of rSO(2, %max) is more than 10.1%, it may act as an early warning index for cognitive function changes. POCD after OLV may be associated with a decline in rSO2.

The Past and Future of Occupational Exposure Limits

The Past and Future of Occupational Exposure Limits

Effects of fundamental frequency removal and low-pass filtering on pitch comparisons.

Pitch has been defined as perceptual attribute which allows the ordering of sounds on a frequency-related scale ordered from low to high (Klapuri & Davy, 2006; p. 8). A primary acoustic dimension for determining the pitch of complex periodic sounds is fundamental frequency (Stevens & Volkmann, 1940; Idson & Massaro, 1978). Relationships between the spectral components of complex tones also contribute to pitch. Harmonic relations, in particular, strengthen the sensation of pitch (Plomp, 1976; Terhardt, 1974).In contrast, timbre traditionally has been defined by exclusion. For example, the American Standards Association (1960) defines timbre as attribute of auditory sensation in terms of which a listener can judge that two sounds similarly presented and having the same loudness and pitch are dissimilar. Part of the reason for the adherence to the traditional definition of timbre may be that timbre has repeatedly been demonstrated to consist of several perceptual dimensions. Yet, establishing an inclusive definition critically depends on understanding the nature of each of the various dimensions of timbre. Research that has sought to define timbre dimensions has typically involved the multidimensional scaling (MDS) of timbre dissimilarity judgments for musical instrument tones. Reported MDS solutions have tended to converge on several acoustic correlates for the perceptual dimensions of timbre. These associations are summarized below (Caclin, McAdams, Smith, & Winsberg, 2005; Grey, 1977; Krumhansl, 1989; McAdams, Winsberg, Donnadieu, De Soete, & Krimphoff, 1995; Miller & Carterette, 1975). The correspondence between some timbre dimensions and their putative acoustic correlates also has been confirmed by timbre discrimination tasks in response to acoustic manipulations (Grey & Moorer, 1977; also see McAdams, Beauchamp, & Meneguzzi, 1999).Dimensions of musical instrument timbre fall into three broad categories: temporal, spectrotemporal, and spectral.1 Important temporal information is conveyed during the attack portion of a tone, the most salient characteristic of which is the logarithm of rise time. For example, MDS studies have shown that the logarithm of rise time is strongly correlated with a perceptual dimension of timbre (Caclin et al., 2005; Krimphoff, McAdams, & Winsberg, 1994; McAdams et al., 1995). When attack transients are removed (Saldanha & Corso, 1964) or swapped across instru- ments (Thayer, 1974), the accuracy of instrument recognition suffers.The most commonly referenced spectrotemporal dimension is spectral flux, a measure of (the lack of) harmonic stability over the duration of a tone (e.g., see Krumhansl, 1989). However, this dimension has not always significantly correlated with MDS solutions, and sometimes corresponding perceptual dimensions have been accounted for equally well or better by spectral attributes such as spectral irregularity (Krimphoff et ah, 1994) or the relative intensity of odd versus even harmonics (Caclin et al., 2005), both of which contribute to the jaggedness of the spectrum. Several alternative spectrotemporal attributes have been determined to contribute to timbre when controlling for spectral flux, as well as spectral envelope shape and rise time (McAdams et ah, 1999; also see Beauchamp & Lakatos, 2002).The current investigation sought to understand the potential impact on pitch made by spectral timbre information. One primary spectral attribute of timbre is brightness, which is related to the relative amount of higher-frequency energy, and is strongly correlated with spectral centroid, an intensity-weighted average of the frequencies in a tone (Schubert & Wolfe, 2006). Because spectral centroid strongly correlates with a primary perceptual dimension in MDS solutions, it has repeatedly been inferred that listeners use perceived brightness to differentiate between musical instruments (Ehresman & Wessel, 1978). …

Buyer Beware: The Consumers' Research Archives at the Rutgers University Libraries

Today, consumer testing and rating guides are taken for granted. It is not unusual for a shopper to take a copy of Consumer Reports to a stereo or appliance store, or consult any number of specialized consumer publications before purchasing a particular product. Prior to 1927, there were no organizations dedicated to helping consumers choose between competing brands of products. Frederick J. Schlink, born in Peoria, Illinois, in 1891, pioneered the effort to research and disseminate unbiased product information to consumers. Trained as an engineer, Schlink had acquired extensive experience in the field of standardization at the National Bureau of Standards in Washington, DC, and with the American Standards Association in New York City. He combined his interest in the standardization of products created for mass production, a disdain for bogus advertising claims, and a background in testing products to form the Consumers' Club in New York City in 1927. With the publication of his book Your Money s Worth (co-authored with Stuart Chase) in the same year, public sentiment was stirred to demand a consumer testing organization. This book exposed the excesses of advertising and the hazards of shoddy products, and called for independent product testing. The overwhelming response to the Your Money's Worth led to the publication of the first consumer rating bulletin entitled The Consumers ' Club Commodity List. The first issue of The List was published on October 27, 1927. In the introduction, Schlink explained that The List was the first step toward giving the small consumer access to critical information about everyday products. The format of the bulletin included two columns subdivided by various products. Products endorsed by The List were filed directly under a column A list; those commodities receiving a negative mark from the compilers were placed in the B list. No direct testing of

Standards for acoustical instruments

Prior to 1930, sounds were classified from subjective judgments of loudness. General-purpose instruments that could make objective measurements of sounds were not yet developed, nor were there any national or international standards with specifications for the performance characteristics of such instruments. In recognition of the need for instruments that could provide objective measurements of a sound, as well as the need for a national consensus on the characteristics of a sound to be measured, the newly founded Acoustical Society of America established Sectional Committees in 1930 to develop such standards under the procedures of the American Standards Association (now the American National Standards Institute). A draft of a standard for sound level meters prepared by the subcommittee for Sound Levels and Sound Level Meters was considered at a meeting of the Sectional Committee in May 1934. After incorporating revisions in response to comments and suggestions, the draft standard for sound level meters was approved for publication by the American Standards Association on 17 February 1936. This paper describes the development of sound level meters and other instruments; along with related national and international standards, in the years since that auspicious beginning.

Acoustical standards in the Society: Historical perspective

The Acoustical Society of America has been active in national standards since 1932 when it asked the American Standards Association to initiate a project to standardize acoustical measurements and terminology. The new committee was assigned to the Society and designated Z24. By 1942, Z24 had expanded to include vibration. By 1957 the activity had grown so much that Z24 was split into three committees: S1 Acoustics, S2 Mechanical Vibration and Shock, and S3 Bioacoustics. (S12 Noise was added later, in 1981). Until 1969, these committees were administered by the USA Standards Institute, the predecessor of the American National standards Institute (ANSI), and new standards were approved by the Executive Council of the Society. In 1971, the Society assumed the responsibility for developing the US position on international standards in acoustics being generated by TC108 of the International Organization for Standardization. During the early 1970s ANSI became the body to approve all national standards, and the Soceity became a standards developer. ASA established a Committee on Standards (ASACOS) in 1978 to guide the work of the S-Committees and the Standards Secretariat. In the past few years ASACOS has increasingly improved its links with the Society’s other technical activities.

Historical review of RF exposure standards and the International Committee on Electromagnetic Safety (ICES).

Focused research on the biological effects of exposure of humans and animals to radio frequency (RF) and microwave energy goes back at least five decades. The history of committees that develop safety standards based on the results of this research goes back almost as far. One such committee that has played a major role in developing such standards is the International Committee on Electromagnetic Safety (ICES), which began in 1960 as the American Standards Association C95 Committee. This paper briefly reviews the history of this committee and its role in the development of RF safety standards. The process now being followed by ICES and its sponsor, the IEEE Standards Association Standards Board (SASB), is discussed, as are a number of issues related to standards setting, such as the poor quality of much of the research and the seemingly endless speculation and search for mechanisms of interaction other than heating. Finally, a tribute is given to Dr. Eleanor Adair, a long-time researcher and supporter of science-based standards. As Chairman of ICES, she makes it clear that her goal and the goal of ICES is to establish rational standards that will make future beneficial applications of RF energy credible to humanity.

Z24-X-2 forty years later

In 1954, Exploratory Subcommittee Z24-X-2 of the American Standards Association issued a report entitled ‘‘The Relations of Hearing Loss to Noise Exposure’’ in which the first attempt was made to integrate the existing evidence concerning how exposure to industrial noise produced hearing loss. Although the subcommittee members were fully aware that limits of exposure would ultimately depend as much on political (social, monetary, and legal) considerations as on scientific evidence, it was judged worthwhile to try to provide as firm a scientific basis as possible for setting those limits. Considering the meager amount of reliable audiometric data that existed then, it is amazing how well their conclusions have been substantiated by subsequent evidence, even though those conclusions have sometimes been overridden by political forces. Present knowledge will be compared with some of the Report’s main aspects: the biological baseline; age corrections; additivity of noise-induced loss and age effect; individual susceptibility; contamination of data by temporary threshold shift; susceptibility of the already-damaged ear; and the inadequacy of total energy as a measure of exposure. Progress toward solution of a list of ‘‘unsolved problems’’ will also be summarized.

Complex mixtures in industrial workspaces: lessons for indoor air quality evaluations.

Acceptable occupational exposure levels for hundreds of airborne concentrations of dusts, vapors, fumes, and gases have been set by consensus organizations and regulatory bodies for decades. These levels have established tremendous precedent and are tempting reference values in the relatively new field of indoor air quality evaluations where validated criteria are greatly needed. The American Conference of Government Industrial Hygienists (ACGIH) has been the most visible and productive group setting these guidelines for industrial exposure. The ACGIH Chemical Substances Committee has published an annual list of threshold limit values (TLVs) for more than 40 years. Currently the list covers more than 400 substances. In 1989, the Occupational Safety and Health Administration (OSHA) published updated permissible exposure limits (PELs) for approximately 600 substances. Most PELs before this update were adopted from the 1968 ACGIH list of TLVs and consensus standards of the American Standards Association. This OSHA update has resulted in reductions of 212 PELs and the addition of 164 new levels. The magnitude of the problem of protecting workers can be seen by the small fraction that the OSHA PELs represent of the more than 60,000 entries in the National Institute for Occupational Safety and Health's Registry of Toxic Effects of Chemical Substances. None of these levels, whether guidelines or regulatory requirements, are established based on any possible synergistic effect with other chemicals. The only guidance given by the ACGIH for synergistic effects is that such cases must be determined individually. Clearly, there are major drawbacks in using occupational standards and guidelines for evaluating the health effects of chemical agents that can be found in office settings, often in concentrations orders of magnitude less than what is routinely measured in the workplace. These guidelines are even less valuable when the concern is the complex mixing of chemicals in nonoccupational environments.

Recollections of a contemporary of Laurence Batchelder, concerning “Preferred reference quantities for acoustic levels, ISO 1683–1983.”

Laurence Batchelder became a member of the Acoustical Society of America in 1946, having already been employed by the Submarine Signal Company for 17 years in the development of underwater SOund NAvigation and Ranging equipment. He was a strong and successful proponent of referring an acoustical level to one unit of the Systéme International as illustrated in the following. In 1946, sound‐pressure level in water at a stated distance from a SONAR projector was typically referred to 1 dyn/cm2; sound‐pressure level radiated by a submarine was typically referred to 0.0002 dyn/cm2; sound‐pressure level in air measured by a standard sound‐level meter was referred to 0.0002 dyn/cm2. At a request of the U. S. Navy in 1961, American Standards Association Working Group SI‐44 was appointed to propose reference quantities for acoustical levels. After much negotiation, S1. 8‐1969 was approved, including a new reference pressure 10−5 dyn/cm2 = 1 micropascal (μPa) for liquids; 2 × 10−4 dyn/cm2 = 20 μPa was retained as the reference for gases. Also in 1961, when the British Standards Institution held the Secretariat for Technical Committee 43, Acoustics, of the International Organization for Standardization (ISO), the Netherlands Member Body proposed that the single reference pressure for sound‐pressure level in all gases and fluids be 2 × 10−5 N/m2 = 20 μPa. After a 12‐year succession of drafts and ballots, during which the BSI relinquished the Secretariat for TC43 to Denmark, a new Working Group 43‐14 was appointed whose effort culminated in ISO 1683–1983; 20 μPa was confirmed as the reference pressure for air, and 1 μPa was standardized for media other than air. The goal proposed by The Netherlands in 1961—only one reference pressure for sound‐pressure levels in all gases and fluids—has not been attained.

The Misexpansion Disorders: ASA

To the Editor.— In the same issue ASA is again called the American Standards Association. 1 This must really anger anesthesiologists. (I'm an internist.)

Adynamic Ileus Following Induced Hypotension

To the Editor.— During a study of the effects of nitroprusside-induced hypotension on surgical bleeding, we incidentally noticed the frequent occurrence of postoperative adynamic ileus in patients whose mean arterial systolic blood pressure (BP) was maintained at the 50- to 65-mm Hg range intraoperatively. Study.— Fifty consecutive patients scheduled for elective total hip replacement were divided into three groups according to their medical condition. Group 1 consisted of 26 healthy patients (American Standards Association physical status, 1 or 2) with no clinical evidence of cerebrovascular disease and with a resting diastolic BP of less than 100 mm Hg. Group 2 included 12 patients with known hypertension and a resting diastolic pressure of greater than 100 mm Hg but with no clinical evidence of cerebrovascular and/or renal disease (ASA physical status 2 or 3). Group 3 included 12 patients, all of whom were ASA physical status 3 or higher, who had