Audio spectrum and sound pressure levels vary between pulse oximeters

PURPOSE: The variable-pitch pulse oximeter is an important intraoperative patient monitor. Our ability to hear its auditory signal depends on its acoustical properties and our hearing. This study quantitatively describes the audio spectrum and sound pressure levels of the monitoring tones produced by five variable-pitch pulse oximeters. METHODS: We compared the Datex-Ohmeda Capnomac Ultima, Hewlett-Packard M1166A, Datex-Engstrom AS/3, Ohmeda Biox 3700, and Datex-Ohmeda 3800 oximeters. Three machines of each of the five models were assessed for sound pressure levels (using a precision sound level meter) and audio spectrum (using a hanning windowed fast Fourier trans-form of three beats at saturations of 99%, 90%, and 85%). RESULTS: The widest range of sound pressure levels was produced by the Hewlett-Packard M1166A (46.5 +/- 1.74 dB to 76.9 +/- 2.77 dB). The loudest model was the Datex-Engstrom AS/3 (89.2 +/- 5.36 dB). Three oximeters, when set to the lower ranges of their volume settings, were indistinguishable from background operating room noise. Each model produced sounds with different audio spectra. Although each model produced a fundamental tone with multiple harmonic overtones, the number of harmonics varied with each model; from three harmonic tones on the Hewlett-Packard M1166A, to 12 on the Ohmeda Biox 3700. There were variations between models, and individual machines of the same model with respect to the fundamental tone associated with a given saturation. CONCLUSION: There is considerable variance in the sound pressure and audio spectrum of commercially-available pulse oximeters. Further studies are warranted in order to establish standards.     

Soleus H-reflex measures in patients with focal and generalized dystonia.

OBJECTIVE: The purpose of this study was to examine neurophysiological characteristics of dystonia patients using electromyographic soleus H-reflex methods. METHODS: Thirty normal healthy individuals were compared to 27 patients with focal (cervical) or generalized dystonia. Three H-reflex assessment methods were included: the ratio of maximum H-reflex to direct muscle potential (H/M ratio); vibration inhibition (H(v)/H(c) ratio); and H-reflex recovery curves (HRRC). RESULTS: Average H/M ratios between groups were not statistically significant. The average H(v)/H(c) ratio for the generalized dystonia group was significantly greater than the focal dystonia and normal groups. Average values of the HRRC showed the generalized dystonia group had significantly greater disinhibition than the focal dystonia and control groups during the early inhibition phase. The HRRC for the focal dystonia group was greater than normal and more similar to the generalized dystonia group during the late phases of the recovery curve. The average value of the localized late facilitation phase for the focal dystonia group was significantly greater than the control group and less than the generalized dystonia group. No differences were observed between groups for the average localized late inhibition phase of the recovery curve. CONCLUSIONS: Soleus H-reflex measures identified neurophysiologic differences between generalized dystonia, cervical dystonia and normal conditions. SIGNIFICANCE: This methodology enables analysis of the underlying characteristics of dystonic pathologies using soleus H-reflex methods rather than upper extremity H-reflex techniques.     

Acquired lacrimal cyst: a rare entity

The case is reported of a 37-year-old woman who complained of a gradually progressive mass in the left medial canthus area of one year's duration associated with epiphora. Although the clinical and investigative observations were suggestive of an acquired lacrimal sac cyst, the diagnosis was clinched by the operative and histopathological findings. Excision of the cyst along with dacryocystorhinostomy provided complete cure for this patient.     

Modeling the Impact of PrEP Programs for Adolescent Sexual Minority Males Based on Empirical Estimates for the PrEP Continuum of Care

PurposePre-exposure prophylaxis (PrEP)—an effective and safe intervention to prevent HIV transmission—was recently approved by the Food and Drug Administration for use by adolescents. Informed by studies of sexual behavior and PrEP adherence, retention, and promotion, we model the potential impact of PrEP use among at-risk adolescent sexual minority males.MethodsWe simulate an HIV epidemic among men who have sex with men (MSM) aged 13–39. We assume adult MSM ages 19–39 have had PrEP available for 3 years with 20% coverage among eligible MSM based on the Centers for Disease Control and Prevention guidelines. PrEP interventions for ages 16–18 are then simulated using adherence and retention profiles drawn from the ATN113 and Enhancing Preexposure Prophylaxis in Community studies across a range of uptake parameters (10%–100%). Partnerships across age groups were modeled using parameterizations from the RADAR study. We compare the percent of incident infections averted (impact), person-years on PrEP per infection averted (efficiency), and changes in prevalence over 10 years.ResultsAs compared to no PrEP use, baseline PrEP adherence and retention among adolescent sexual minority males drawn from the ATN113 and Enhancing Preexposure Prophylaxis in Community studies averted from 2.8% to 41.0% of HIV infections depending on the fraction of eligible adolescent sexual minority males that initiated PrEP at their annual health-care visit. Improved adherence and retention achieved with an array of focused interventions from real-world settings increased the percent of infections averted by as much as 26%–70%.ConclusionsEmpirically demonstrated improvements in the PrEP continuum of care in response to existing interventions can substantially reduce incident HIV infections among adolescent sexual minority males.     

COVID-19 and hemolysis,elevated liver enzymes and thrombocytopenia syndrome in pregnant women - association or causation?

Pregnant women are among the high-risk population for severe coronavirus disease 2019 (COVID-19) with unfavorable peripartum outcomes and increased incidence of preterm births. Hemolysis, the elevation of liver enzymes, and low platelet count (HELLP) syndrome and severe preeclampsia are among the leading causes of maternal mortality. Evidence supports a higher odd of pre-eclampsia in women with COVID-19, given overlapping pathophysiology. Involvement of angiotensin-converting enzyme 2 receptors by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for the entry to the host cells and its downregulation cause dysregulation of the renin-angiotensin-aldosterone system. The overexpression of Angiotensin II mediated via p38 Mitogen-Activated Protein Kinase pathways can cause vasoconstriction and uninhibited platelet aggregation, which may be another common link between COVID-19 and HELLP syndrome. On PubMed search from January 1, 2020, to July 30, 2022, we found 18 studies on of SARS-COV-2 infection with HELLP Syndrome. Most of these studies are case reports or series, did not perform histopathology analysis of the placenta, or measured biomarkers linked to pre-eclampsia/HELLP syndrome. Hence, the relationship between SARS-CoV-2 infection and HELLP syndrome is inconclusive in these studies. We intend to perform a mini-review of the published literature on HELLP syndrome and COVID-19 to test the hypothesis on association vs causation, and gaps in the current evidence and propose an area of future research.     

Bedside ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure in nontraumatic neuro-critically ill patients

BACKGROUND Delay in treatment of raised intracranial pressure(ICP) leads to poor clinical outcomes. Optic nerve sheath diameter(ONSD) by ultrasonography(US-ONSD)has shown good accuracy in traumatic brain injury and neurosurgical patients to diagnose raised ICP. However, there is a dearth of data in neuro-medical intensive care unit(ICU) where the spectrum of disease is different.AIM To validate the diagnostic accuracy of ONSD in non-traumatic neuro-critically ill patients.METHODS We prospectivel...     

Role of cerebrospinal fluid lactate in diagnosing meningitis in critically ill patients

BACKGROUND Meningitis is a life-threatening clinical condition associated with high mortality and morbidity. Early diagnosis and specific treatment may improve outcomes.Lack of specific clinical signs or tests make the diagnosis challenging.AIM To assess the efficacy of cerebrospinal fluid(CSF) lactate in diagnosing meningitis in critically ill patients.METHODS A prospective, observational cohort study was carried out in a neuro-medical intensive care unit(ICU) over a 22 mo period. Adult patient...