A clinical audit of an office-based anaesthesia service for dental procedures in Victoria.

There is an increasing number of specialties performing office-based procedures, with many different providers practising in this field. Office Based Anaesthesia Solutions is a private enterprise designed to be a high-quality general anaesthesia and sedation service delivering care across 18 dental practices in Victoria. We undertook a criterion-based audit of our practice standards and outcomes. Following ethics approval, we retrospectively reviewed consecutive patients managed by our service between March 2014 and July 2017. We collected demographic data, information about anaesthesia technique, and surgical features. We assessed our findings against the Australian and New Zealand College of Anaesthetists (ANZCA) day surgery policy documents. During the specified period, we provided anaesthesia or sedation for 1,323 patients. Their ages ranged from two to 93 years (mean [standard deviation] 33.3 [18.6] years). Ninety-three percent of patients were American Society of Anesthesiologists (ASA) physical status classification 1 or 2. Patient demographics were in line with ANZCA day surgical policy documents. Total intravenous anaesthesia was used in 1,054 of the 1,096 documented general anaesthesia cases. There were three unplanned hospital transfers (annual incidence 0.07%). As this was the first Australian criteria-based audit of office-based anaesthesia (OBA) for dental procedures, we cannot compare our findings directly to previous studies. However, we feel that our patient demographics fell within acceptable ANZCA day procedure standards and our adverse event rate was both very low and similar to other published international adverse event rates. Our audit indicates that with careful screening processes, patient selection and medical governance, OBA is a viable model of care for patients undergoing dental procedures.

Relationship between insulin sensitivity and insulin secretion rate: not necessarily hyperbolic.

AIMS: There is general acceptance that the physiological relationship between insulin sensitivity and insulin secretion is hyperbolic. This conclusion has evolved from studies in which one test assessed both variables, and changes in plasma insulin concentration were used as a surrogate measure for insulin secretion rate. The aim of this study was to see if a hyperbolic relationship would also emerge when separate and direct measures were used to quantify both insulin sensitivity and insulin secretion rate. METHODS: Steady-state plasma glucose (SSPG) was determined in 146 individuals without diabetes using the insulin suppression test, with 1/SSPG used to quantify insulin sensitivity. The graded-glucose infusion test was used to quantify insulin secretion rate. Plasma glucose and insulin concentrations obtained during an oral glucose tolerance test (OGTT) were used to calculate surrogate estimates of insulin action and insulin secretion rate. A hyperbolic relationship was assumed if the ß coefficient was near -1 using the following model: log (insulin secretion measure) = constant + ß × log (insulin sensitivity measure). RESULTS: OGTT calculations of insulin sensitivity (Matsuda) and plasma insulin response [ratio of insulin/glucose area-under-the-curve (AUC) or insulin total AUC] provided the expected hyperbolic relationship [ß = -0.95, 95% CI (-1.09, -0.82); -1.06 (-1.14, -0.98)]. Direct measurements of insulin sensitivity and insulin secretion rate did not yield the same curvilinear relationship [ß = -1.97 (-3.19, -1.36)]. CONCLUSIONS: These findings demonstrate that the physiological relationship between insulin sensitivity and insulin secretion rate is not necessarily hyperbolic, but will vary with the method(s) by which it is determined.

Moral status: what a bad idea!

BACKGROUND: Advocates of people with disabilities sometimes have advanced their cause within a conceptual frame of human exceptionalism, shaped specifically by one or another proposal about a moral property or capacity with which human individuals alone are endowed. METHODS: This essay is a philosophical reflection about the notion of moral status. RESULTS: Arguments presented here show, however, that framing the pursuit of protection for people with disabilities in terms of humanity's exceptional moral status is more hazardous than helpful. CONCLUSIONS: Appeals to moral status do not settle debates about whether there are obligations to provide protection and support for individuals with disabilities because the idea of moral status is as contentious as the disagreements it is invoked to resolve.

A retrospective observational study examining the admission arterial to end-tidal carbon dioxide gradient in intubated major trauma patients.

Major trauma patients who are intubated and ventilated are exposed to the potential risk of iatrogenic hypercapnic and hypocapnic physiological stress. In the pre-hospital setting, end-tidal capnography is used as a practical means of estimating arterial carbon dioxide concentrations and to guide the adequacy of ventilation. In our study, potentially deleterious hypercapnia (mean 47 mmHg, range 26 to 83 mmHg) due to hypoventilation was demonstrated in 49% of 100 intubated major trauma patients arriving at a major Australian trauma centre. A mean gradient of 15 mmHg arterial to end-tidal carbon dioxide concentration difference was found, highlighting the limitations of capnography in this setting. Moreover, 80% of the patients in the study had a head injury. Physiological deadspace due to hypovolaemia in these patients is commonly thought to contribute to the increased arterial to end-tidal carbon dioxide gradient in trauma patients. However in this study, scene and arrival patient hypoxia was more predictive of hypoventilation and an increased arterial to end-tidal carbon dioxide gradient than physiological markers of shock. Greater vigilance for hypercapnia in intubated trauma patients is required. Additionally, a larger study may confirm that lower end-tidal carbon dioxide levels could be safely targeted in the pre-hospital and emergency department ventilation strategies of the subgroup of major trauma patients with scene hypoxia.

Cyclin D1 as a proliferative marker regulating retinoblastoma phosphorylation in mouse lung epithelial cells.

Elevations in cyclin D1 content increase the phosphorylation status of retinoblastoma (Rb) protein to encourage cell cycle transit. We sought to determine if cyclin D1 content could be used as an index of cell proliferation in mouse lung epithelia following growth manipulations in vitro and in vivo. Rb protein concentration was high in 82-132 and LM2, two fast-growing neoplastic mouse lung epithelial cell lines. The hyperphosphorylated form of Rb predominated in these two cell lines, while Rb in slower-growing cell lines was predominantly hypophosphorylated. Consistent with this, more cyclin D1 protein was expressed in the fast-growing cell lines than in slower-growing cells. We therefore tested whether cyclin D1 content varied with growth status. The amount of cyclin D1 decreased upon serum removal coincident with growth inhibition and then increased upon serum re-addition which stimulated resumption of proliferation. This correlation between cyclin D1 content and growth status also occurred in vivo. Cyclin D1 content increased when lungs underwent compensatory hyperplasia following damage caused by butylated hydroxytoluene administration to mice and in lung tumor extracts as compared with extracts prepared from uninvolved tissue or control lungs. We conclude that elevated cyclin D1 levels account, at least in part, for the hyperphosphorylation of Rb in neoplastic lung cells, and are associated with enhanced lung growth in vitro and in vivo.

Inactivation of both Rb and p53 pathways in mouse lung epithelial cell lines.

Aberrant expression of key cell cycle regulatory genes is essential for the immortalization and transformation of cells in vitro. We examined 20 mouse lung epithelial cell lines (2 nontumorigenic, 5 nonmetastatic, and 13 metastatic) for mutations or alterations in the expression of key components of the Rb pathway (pRb and p16INK4a) and the p53 pathway (p53 and p19ARF). Seven cell lines had a mutation in exons 5 to 8 of p53. p19ARF was inactivated in the remaining 13 cell lines, primarily by homozygous deletion. Rb expression was present and unaltered in all cell lines, with both phosphorylated and unphosphorylated protein forms detectable. p16INK4a transcripts were undetectable in all cell lines tested except LM1. Loss of p16INK4a expression was a result of homozygous deletion in 11 out of 20 lung cell lines and promoter-exon 1 hypermethylation in 6 out of the remaining 8 cell lines. Other related components that were examined in this study included p21WAF1 and cyclin D1. Compared to normal lung tissue, p21WAF1 expression levels were reduced or undetectable in all cell lines, which did not correlate with loss of p53 function, but did correlate with inactivation of either p53 or p19ARF. Although cyclin D1 expression was variable between cell lines, transcript levels were decreased by at least 50% in the nontumorigenic lines C10 and E10 compared to the tumorigenic cell lines. These results demonstrate mutually exclusive relationships between p53 and p19ARF and between Rb and p16INK4a, but perhaps not between cyclin D1 and p16INK4a, and further describe the nature of involvement of both pathways in mouse lung tumorigenesis.

New fossil hominid calvaria from Indonesia--Sambungmacan 3.

A morphologically distinct partial calvaria of Homo cf. erectus from Java, Indonesia is described. The fossil hominid Sambungmacan 3 (Sm 3) was first discovered in 1977 from the banks of the Solo River near the village of Poloyo, Sambungmacan district, in central Java. It was later recovered in a New York City natural history establishment in 1999 and quickly returned to the Indonesian authorities. Examination of Sm 3 shows that the calvaria is well preserved with only portions of the cranial base missing. The most striking characteristics of Sm 3 include: the presence of a vertically rising forehead, more open occipital/nuchal and frontal angles, a more globular vault, and a cranial capacity within the Homo erectus range. Most notably absent in Sm 3 are a number of the classic characters attributed to Homo erectus, such as a strongly expressed angular torus and a continuous supratoral sulcus. The absence of such characters would normally place the calvaria outside the range of Homo erectus (sensu stricto), however, overall quantitative and qualitative morphological assessments of Sm 3 place it within the Homo erectus spectrum. The combination of the morphological characters in Sm 3 may be interpreted in several ways: 1.) the known cranial variation of H. erectus from Indonesia and China is extended; 2.) this calvaria shows evidence of evolutionary change within H. erectus; or 3.) more than one species of Homo existed in the (presumed) Middle Pleistocene of Java.)

Endocast of Sambungmacan 3 (Sm 3): a new Homo erectus from Indonesia.

A new fossil calvaria, Sambungmacan 3 (Sm 3), described in New Fossil Hominid Calvaria From Indonesia--Sambungmacan 3 by Márquez et al., this volume, yields one of the most advanced and complete endocasts yet recovered from Java. This communication provides a thorough interpretation of the external anatomical landmarks observable on Sm 3. Using computer tomography (CT) and traditional morphological measurements, our comparative paleoneurological analyses show that while Sm 3 has a mosaic of features that are similar to both Indonesian and Chinese H. erectus, it also possesses significant characters reminiscent of later hominins. These include a greater degree of asymmetry characterized by a possible left-occipital, right-frontal petalial pattern, left-right volumetric cerebral asymmetry, and marked asymmetry in Broca's cap. Moreover, the frontal lobe offers a more rounded, shortened appearance in contrast to the flat, elongated appearance of other Indonesian fossils (e.g., Sangiran 17). Another unique trait is exhibited in the transverse plane where the widest breadth of Sm 3 occurs more superiorly than in other Indonesian H. erectus. Thus, the endocast of Sm 3 presents a unique morphology not seen previously in the hominin fossil record. While the strong modern human characteristics in this endocast may not represent a particular ancestry, they do allow us to recognize a new dimension of the remarkable variation in Indonesian Homo erectus.

Delayed signal detection by diffusion-weighted imaging in brainstem infarction.

Diffusion-weighted magnetic resonance imaging (DW MRI) is a sensitive and specific technique for imaging acute hemispheric infarction. Its utility in the diagnosis of acute brainstem infarction has not been well studied. We present 3 cases of brainstem infarction in which DW MRI performed 5 to 15 hours after symptom onset failed to reveal any abnormality. Repeat diffusion-weighted imaging (DWI) 2 to 5 days later did demonstrate an abnormality in the clinically appropriate region in each instance. This suggests that the time course to the development of abnormalities detectable by DWI may be longer in brainstem than in hemispheric infarctions. Therefore, repeat studies after initially negative DWI might be useful in the diagnosis of brainstem infarctions.

Measuring potential exposure to environmental pollutants: time spent with soil and time spent outdoors.

In 1994-1995, the Electric Power Resource Institute (EPRI) undertook a major national survey of time in microenvironments with 1200 respondents aged 18 and older. It did so using a methodology that minimized the problems of respondent recall and reporting by the use of a "time diary," in which survey respondents reported in detail about their actual activities "yesterday" including time spent outdoors. In addition, respondents were asked questions about the extent of contact with soil they had on that day. Significant proportions (20%) of the American public reported coming in direct contact with soil on a typical day and those who did come in contact were exposed for about 1.7 h per day; some 6% of the public reported being exposed for more than 2 h on the day in question, mainly by hand (although 3% of respondents reported soil contact with their head or face). As expected, men reported far more soil contact than women; surprisingly few consistent differences were found by age, or by marital status, parental status or employment status. Contrary to expectations, higher contact was not reported by minorities, or by less educated or less affluent respondents. Moreover, these patterns generally remained unchanged after adjustment for other demographic predictors. More as expected, higher exposure was reported in the Spring months, on weekends, and in rural areas and in the South and West regions of the country, patterns again largely unaffected by multivariate controls for other predictors. In general, while certain predictors of soil exposure were much the same for time spent outdoors, there were some notable exceptions.

Isolated primary unilateral stenosis of the internal auditory canal.

Congenital primary stenosis of the internal auditory canal (IAC) may exist in isolation or along with a number of other osseous anomalies of the temporal bone. Most of the literature on IAC stenosis is concerned with its effect on the outcome of cochlear implantation (i.e. patients with profound bilateral hearing loss). In addition, some degree of canal asymmetry has been noted in patients with normal hearing, questioning the causal relationship of this finding to deafness. We describe two children with computed tomography (CT) documented severe primary unilateral narrowing of the IAC and an associated ipsilateral sensorineural hearing loss. Typical radiographic findings are described, and the relevant developmental pathology is discussed. The ipsilateral association of stenosis and hearing loss strengthens the link between narrowing of the IAC and deafness.

Surveillance CT and the prompt use of CT-guided fine-needle aspiration in patients with head and neck cancer who have undergone surgery.

OBJECTIVE: The purpose of this study was to assess the usefulness of prompt CT-guided fine-needle aspiration in the evaluation of suspected tumor recurrence seen on surveillance images of patients who had undergone surgery for head and neck cancer. SUBJECTS AND METHODS: We reviewed 32 patients who had undergone CT-guided fine-needle aspiration after surgery for head and neck cancer. CT-guided fine-needle aspiration was performed with a 22-gauge spinal needle and a cytopathologist was present to assess the adequacy of the biopsy sample. As many as five needle passes were made. RESULTS: Of the 32 cases, pathologic findings revealed squamous cell carcinoma (n = 27), mucoepidermoid carcinoma (n = 2), neuroendocrine carcinoma (n = 1), papillary thyroid carcinoma (n = 1), and adenocarcinoma (n = 1). In 20 cases (62.5%) the results of CT-guided fine-needle aspiration were positive for tumor recurrence, whereas in 11 cases (34.4%) the results were negative. In one case (3.1%) the results were nondiagnostic. Of the 11 patients with negative findings on CT-guided fine-needle aspiration, two patients had a subsequent recurrence that was not at the biopsy site. There were no complications from the procedure. CONCLUSION: When a radiologist who is trained in head and neck imaging identifies with CT a possible early recurrence of tumor, the prompt use of CT-guided fine-needle aspiration is an effective way to diagnose these tumors so that appropriate treatment can be initiated.

Anaesthesia and postoperative pain management for bilateral lung volume reduction surgery.

Bilateral lung volume reduction surgery was introduced into Australia in 1995 for treatment of selected patients with emphysema. We present our experience of the anaesthetic management of our first 55 cases and describe factors associated with outcome. There were four postoperative deaths (7%). Mean (SD) total operation time was 231 (72) minutes. Median intensive care unit (ICU) stay was 26 hours. There was a significant improvement in postoperative lung function (FEV1, VC, 6-minute walk test, all P < 0.001). Eight patients (15%) required reintubation for respiratory failure; three of these patients subsequently died. With multivariate analysis, total operation time was the only significant predictor of length of ICU stay R2 = 0.25, P = 0.001), which itself was the only significant predictor of hospital stay duration (R2 = 0.36, P < 0.001).

Nonlinearity in the lung cancer dose-response for airborne arsenic: apparent confounding by year of hire in evaluating lung cancer risks from arsenic exposure in Tacoma smelter workers.

Most analytic studies of human epidemiologic data have affirmed the linear association between excess lung cancer risk and airborne arsenic exposure. Recent Canadian analyses, however, based on the mortality follow-up of Tacoma smelter workers from 1940-1976, provided strong evidence of a nonlinear dose-response when lung cancer risk was expressed in terms of the standardized mortality ratio. Using recently updated data covering ten additional years of mortality experience among Tacoma workers (1940-1986), new analyses were undertaken to further explore nonlinearity in the lung cancer dose-response in this worker cohort. Lung cancer risk was expressed in terms of both the standardized mortality ratio (SMR) and the excess mortality rate (EMR). As in Canadian analyses, nonlinearity was assessed through a three parameter model containing both linear and negative exponential terms for dose. Dropping the negative-exponential dose-term lead to the standard suite of linear dose-response models, with and without intercept, used for comparative purposes. Analyses were undertaken by subcohort as there was strong evidence of confounding by year of initial hire, which largely explained the nonlinearity in the dose-response observed in Canadian analyses. Subcohort analyses based on initial employment, prior to 1940 or thereafter, showed that the nonlinearity in the dose-response was strongly influenced by date of initial hire. whether the cohort risk was measured by either the SMR or EMR, a nonlinear dose-response was evident only among workers hired prior to 1940. This, however, was strongly related to the artifactually low lung cancer mortality seen among workers hired between 1930 and 1939. Among workers hired after 1940, analyses showed that a linear dose-response provided a clearly superior fit. While analyses showed comparable goodness of fit when models were fitted to the SMR and EMR. Only those based on the EMR provided strong evidence of a dose-response. Overall, nonlinearity as observed in Canadian analyses was likely the result of several sources of bias not taken into account by Canadian investigators.

Clinical use of the optical digitizer for intracranial neuronavigation.

OBJECTIVE: Computer-assisted frameless navigation techniques are used in many centers for intracranial neurosurgical procedures. In this study, we assessed the accuracy and the clinical usefulness of a frameless system based on the optical digitizer in a variety of intracranial procedures. METHODS: The optical digitizer (StealthStation, Sofamor Danek, Memphis, TN) was used to perform 170 neurosurgical operations. Its accuracy was judged before and after each operation by comparing the computer-estimated error with the real estimated error measured on the patient's anatomy. Several objective factors were evaluated to assess the clinical usefulness of the optical digitizer. For craniotomies, the intraoperative extent of resection based on computer-generated images was compared with that on postoperative images, and the length of hospital stay of patients undergoing frameless procedures was compared with that of patients undergoing conventional procedures. For needle biopsies, clinical usefulness was based on the rate of success in establishing a histological diagnosis. RESULTS: The optical digitizer was accurate to within 2 mm for all procedures. The computer-estimated error was not significantly different from the real estimated error. The intraoperative extent of resection was accurate in 58 of 60 tumor resection patients, as confirmed on postoperative images. Patients undergoing frameless procedures had a significantly shorter hospital stay than those undergoing conventional procedures (7.5 +/- 1 versus 10.8 +/- 1.3 d, P < 0.05). All biopsies were diagnostic. CONCLUSION: The optical digitizer is an accurate frameless device that offers clinical benefits. These include precise surgical resection, decreased hospitalization time, and accurate tissue diagnosis.

Control of spatial orientation of the angular vestibulo-ocular reflex by the nodulus and uvula of the vestibulocerebellum.

Eye velocity produced by the angular vestibulo-ocular reflex (aVOR) tends to align with the summed vector of gravity and other linear accelerations [gravito-inertial acceleration (GIA)]. Defined as "spatial orientation of the aVOR," we propose that it is controlled by the nodulus and uvula of the vestibulocerebellum. Here, electrical stimulation, injections of the GABAA agonist, muscimol, and single-cell recordings were utilized to investigate this spatial orientation. Stimulation, injection, and recording sites in the nodulus were determined in vivo by MRI and verified in histological sections. MRI proved to be a sensitive, reliable way to localize electrode placements. Electrical stimulation at sites in the nodulus and sublobule d of the uvula produced nystagmus whose slow-phase eye-velocity vectors were either head centric or spatially invariant. When head centric, the eye velocity vector remained within +/- 45 degrees of the vector obtained with the animal upright, regardless of head position with respect to gravity. When spatially oriented, the vector remained relatively constant in space in one on-side position, with respect to the vector determined with the animal upright. A majority of induced movements from the nodulus were spatially oriented. Spatially oriented movements were generally followed by after-nystagmus, which had the characteristics of optokinetic after-nystagmus (OKAN), including orientation to the GIA. After muscimol injections, horizontal-to-vertical cross-coupling was lost or reduced during OKAN in tilted positions. This supports the hypothesis that the nodulus mediates yaw-to-vertical or roll cross-coupling. The injections also shortened the yaw-axis time constant and produced contralateral horizontal spontaneous nystagmus, whose velocity varied as a function of head position with regard to gravity. Nodulus units were tested with static head tilt, sinusoidal oscillation around a spatial horizontal axis with the head in different orientations relative to the pitching plane, and off-vertical axis rotation (OVAR). The direction of the response vectors of the otolith-recipient units in the nodulus, determined from static and/or dynamic head tilts, were confirmed by OVAR. These vector directions lay close to the planes of the vertical canals in 7/10 units; many units also had convergent input from the vertical canals. It is postulated that the orientation properties of the aVOR result from a transfer of otolith input regarding head tilt along canal planes to canal-related zones of the nodulus. In turn, Purkinje cells in these zones project to vestibular nuclei neurons to control eye velocity around axes normal to these same canal planes.