Pressure support ventilation with the ProSeal (R) laryngeal mask airway. A comparison of sevoflurane, isoflurane and propofol

Background and objective: There are no data about the influence of anaesthetics on cardiovascular variables during pressure support ventilation of the lungs through the laryngeal mask airway. We compared propofol, sevoflurane and isoflurane for maintenance of anaesthesia with the ProSeal (R) laryngeal mask airway during pressure support ventilation. Methods: Sixty healthy adults undergoing peripheral musculo-skeletal surgery were randomized for maintenance with sevoflurane end-tidal 29%, isoflurane end-tidal 1.1% or propofol 6 mg kg(-1) h(-1) in oxygen 33% and air. Pressure support ventilation comprised positive end-expiratory pressure set at 5 cmH(2)O, and pressure support set 5 cmH(2)O above positive end-expiratory pressure. Pressure support was initiated when inspiration produced a 2 cmH(2)O reduction in airway pressure. A blinded observer recorded cardiorespiratory variables (heart rate, mean blood pressure, oxygen saturation, air-way occlusion pressure, respiratory rate, expired tidal volume, expired minute volume and end-tidal CO2), adverse events and emergence times. Results: Respiratory rate and minute volume were 10-21% lower, and end-tidal CO2 6-11% higher with the propofol group compared with the sevoflurane or isoflurane groups, but otherwise cardiorespiratory variables were similar among groups. No adverse events occurred in any group. Emergence times were longer with the propofol group compared with the sevoflurane or isoflurane groups (10 vs. 7 vs. 7 min). Conclusion: Lung ventilation is less effective and emergence times are longer with propofol than sevoflurane or isoflurane for maintenance of anaesthesia during pressure support ventilation with the ProSeal (R) laryngeal mask airway. However, these differences are small and of doubtful clinical importance.

Cloning and characterization of natriuretic peptides from the venom glands of Australian elapids

The venom from Australian elapid snakes contains a complex mixture of polypeptide toxins that adversely affect multiple homeostatic systems within their prey in a highly specific and targeted manner. Included in these toxin families are the recently described venom natriuretic peptides, which display similar structure and vasoactive functions to mammalian natriuretic peptides. This paper describes the identification and detailed comparative analysis of the cDNA transcripts coding for the mature natriuretic peptide from a total of nine Australian elapid snake species. Multiple isoforms were identified in a number of species and represent the first description of a natriuretic peptide from the venom gland for most of these snakes. Two distinct natriuretic peptide isoforms were selected from the common brown snake (Pseudonaja textilis), PtNP-a, and the mulga (Pseudechis australis), PaNP-c, for recombinant protein expression and functional analysis. Only one of these peptides, PtNP-a, displayed cGMP stimulation indicative of normal natriuretic peptide activity. Interestingly, both recombinant peptides demonstrated a dose-dependent inhibition of angiotensin converting enzyme (ACE) activity, which is predictive of the vasoactive effects of the toxin. The natriuretic peptides, however, did not possess any coagulopathic activity, nor did they inhibit or potentiate thrombin, adenosine diphosphate or arachidonic acid induced platelet aggregation. The data presented in this study represent a significant resource for understanding the role of various natriuretic peptides isoforms during the envenomation process by Australian elapid snakes. (c) 2006 Published by Elsevier Masson SAS.

Ocular blood flow measurements in healthy human myopic eyes

Background. To evaluate the haemodynamic features of young healthy myopes and emmetropes, in order to ascertain the perfusion profile of human myopia and its relationship with axial length prior to reaching a degenerative state. Methods The retrobulbar, microretinal and pulsatile ocular blood flow (POBF) of one eye of each of twenty-two high myopes (N=22, mean spherical equivalent (MSE) =-5.00D), low myopes (N=22, MSE-1.00 to-4.50D) and emmetropes (N=22, MSE±0.50D) was analyzed using color Doppler Imaging, Heidelberg retinal flowmetry and ocular blood flow analyser (OBF) respectively. Intraocular pressure, axial length (AL), systemic blood pressure, and body mass index were measured. Results. When compared to the emmetropes and low myopes, the AL was greater in high myopia (p<0.0001). High myopes showed higher central retinal artery resistance index (CRA RI) (p=0.004), higher peak systolic to end diastolic velocities ratio (CRA ratio) and lower end diastolic velocity (CRA EDv) compared to low myopes (p=0.014, p=0.037). Compared to emmetropes, high myopes showed lower OBFamplitude (OBFa) (p=0.016). The POBF correlated significantly with the systolic and diastolic blood velocities of the CRA (p=0.016, p=0.036). MSE and AL correlated negatively with OBFa (p=0.03, p=0.003), OBF volume (p=0.02, p<0.001), POBF (p=0.01, p<0.001) and positively with CRA RI (p=0.007, p=0.05). Conclusion. High myopes exhibited significantly reduced pulse amplitude and CRA blood velocity, the first of which may be due to an OBF measurement artefact or real decreased ocular blood flow pulsatility. Axial length and refractive error correlated moderately with the ocular pulse and with the resistance index of the CRA, which in turn correlated amongst themselves. It is hypothesized that the compromised pulsatile and CRA haemodynamics observed in young healthy myopes is an early feature of the decrease in ocular blood flow reported in pathological myopia. Such vascular features would increase the susceptibility for vascular and age-related eye diseases.

Macular pigment optical density is related to blood glutathione levels in healthy individuals

Purpose. To assess the relationship between macular pigment optical density (MPOD) and blood markers for antioxidant defense in otherwise healthy volunteers. Methods. Forty-seven healthy volunteers were subjected to blood analysis to detect the level of circulating glutathione in its reduced (GSH) and oxidized (GSSG) forms. The level of MPOD was measured using heterochromatic flicker photometry. Systemic blood pressure (BP) parameters, heart rate (HR), body mass index (BMI), and plasma levels of total, HDL, and LDL cholesterol and triglycerides (TGs) were also determined. Results. A simple correlation model revealed that the level of MPOD correlated significantly and positively with both GSH (P < 0.001) and t-GSH (P < 0.001) levels but not with those of GSSG (P > 0.05). Age, sex, systemic BP parameters, HR, BMI, and plasma levels of cholesterol and TGs did not have any influence on either MPOD or glutathione levels (all P > 0.05). In addition, a forward stepwise multiple regression analysis showed MPOD to have a significantly and independent correlation with GSH levels (ß = 0.63; P < 0.001). Conclusions. In otherwise healthy older individuals, there is a positive correlation between local and systemic antioxidant defense mechanisms.

Analysis of the intraocular pressure pulse

This thesis was concerned with investigating methods of improving the IOP pulse’s potential as a measure of clinical utility. There were three principal sections to the work. 1. Optimisation of measurement and analysis of the IOP pulse. A literature review, covering the years 1960 – 2002 and other relevant scientific publications, provided a knowledge base on the IOP pulse. Initial studies investigated suitable instrumentation and measurement techniques. Fourier transformation was identified as a promising method of analysing the IOP pulse and this technique was developed. 2. Investigation of ocular and systemic variables that affect IOP pulse measurements In order to recognise clinically important changes in IOP pulse measurement, studies were performed to identify influencing factors. Fourier analysis was tested against traditional parameters in order to assess its ability to detect differences in IOP pulse. In addition, it had been speculated that the waveform components of the IOP pulse contained vascular characteristic analogous to those components found in arterial pulse waves. Validation studies to test this hypothesis were attempted. 3. The nature of the intraocular pressure pulse in health and disease and its relation to systemic cardiovascular variables. Fourier analysis and traditional parameters were applied to the IOP pulse measurements taken on diseased and healthy eyes. Only the derived parameter, pulsatile ocular blood flow (POBF) detected differences in diseased groups. The use of an ocular pressure-volume relationship may have improved the POBF measure’s variance in comparison to the measurement of the pulse’s amplitude or Fourier components. Finally, the importance of the driving force of pulsatile blood flow, the arterial pressure pulse, is highlighted. A method of combining the measurements of pulsatile blood flow and pulsatile blood pressure to create a measure of ocular vascular impedance is described along with its advantages for future studies.

Reduction in blood glutathione levels occurs similarly in patients with primary-open angle or normal tension glaucoma

PURPOSE. To investigate in parallel the systemic glutathione levels of patients suffering from primary open angle glaucoma (POAG) or normal tension glaucoma (NTG) with comparable functional loss. METHODS. Thirty-four POAG patients, 30 NTG patients, and 53 controls were subjected to blood analysis to detect the level of circulating glutathione in its reduced (GSH) and oxidized (GSSG) forms. Systemic blood pressure (BP) and ocular perfusion pressure (OPP) parameters were also determined. RESULTS. Independent of age, POAG and NTG patients demonstrated significantly lower GSH and t-GSH levels than age-matched controls (P < 0.001). Additionally, a lower redox index was found, but in POAG patients only, in comparison to both NTG and control groups (P = 0.020). GSSG levels were, however, similar between all study groups (P > 0.05). CONCLUSIONS. This study demonstrates, for the first time, that both POAG and NTG patients exhibit lower GSH and t-GSH levels than age-matched controls, indicating a similar general compromise of the antioxidant defense systems may exist in both conditions. © 2013 The Association for Research in Vision and Ophthalmology, Inc.

Patients with early age-related macular degeneration exhibit signs of macro- and micro-vascular disease and abnormal blood glutathione levels

Background: This pilot study aimed to investigate systemic and retinal vascular function and their relationship to circulatory markers of cardiovascular risk in early age-related macular degeneration (AMD) patients without any already diagnosed systemic vascular pathologies. Methods: Fourteen patients diagnosed with early AMD and 14 age- and gender-matched healthy controls underwent blood pressure, carotid intima-media thickness (C-IMT) and peripheral arterial stiffness measurements. Retinal vascular reactivity was assessed by means of dynamic retinal vessel analysis (DVA) using a modified protocol. Blood analyses were conducted for glutathione levels and plasma levels of total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG). Results: The AMD patients showed significantly greater C-IMT (p = 0.029) and augmentation index (AIx) (p = 0.042) than the age-matched controls. In addition, they demonstrated a shallower retinal arterial dilation slope (Slope AD) (p = 0.005) and a longer retinal venous reaction time (RT) to flickering light (p = 0.026). Blood analyses also revealed that AMD patients exhibited higher oxidized glutathione (GSSG) (p = 0.024), lower redox index (p = 0.043) and higher LDL-C (p = 0.033) levels than the controls. Venous RT parameter correlated positively with blood GSSG levels (r = 0.58, p = 0.038) in AMD subjects, but not in the controls (p > 0.05). Conclusions: Patients diagnosed with early AMD exhibit signs of systemic and retinal vascular alterations that correlated with known risk markers for future cardiovascular morbidity. © 2013 Springer-Verlag Berlin Heidelberg.

Psychological traits influence autonomic nervous system recovery following esophageal intubation in health and functional chest pain

Background: Esophageal intubation is a widely utilized technique for a diverse array of physiological studies, activating a complex physiological response mediated, in part, by the autonomic nervous system (ANS). In order to determine the optimal time period after intubation when physiological observations should be recorded, it is important to know the duration of, and factors that influence, this ANS response, in both health and disease. Methods: Fifty healthy subjects (27 males, median age 31.9 years, range 20-53 years) and 20 patients with Rome III defined functional chest pain (nine male, median age of 38.7 years, range 28-59 years) had personality traits and anxiety measured. Subjects had heart rate (HR), blood pressure (BP), sympathetic (cardiac sympathetic index, CSI), and parasympathetic nervous system (cardiac vagal tone, CVT) parameters measured at baseline and in response to per nasum intubation with an esophageal catheter. CSI/CVT recovery was measured following esophageal intubation. Key Results: In all subjects, esophageal intubation caused an elevation in HR, BP, CSI, and skin conductance response (SCR; all p < 0.0001) but concomitant CVT and cardiac sensitivity to the baroreflex (CSB) withdrawal (all p < 0.04). Multiple linear regression analysis demonstrated that longer CVT recovery times were independently associated with higher neuroticism (p < 0.001). Patients had prolonged CSI and CVT recovery times in comparison to healthy subjects (112.5 s vs 46.5 s, p = 0.0001 and 549 s vs 223.5 s, p = 0.0001, respectively). Conclusions & Inferences: Esophageal intubation activates a flight/flight ANS response. Future studies should allow for at least 10 min of recovery time. Consideration should be given to psychological traits and disease status as these can influence recovery. The psychological trait of neuroticism retards autonomic recovery following esophageal intubation in health and functional chest pain. © 2013 John Wiley & Sons Ltd.

The Effect of Carbohydrate Amount, Quality and Type on Arterial Pulse Pressure in Cuban-Americans with and Without Type 2 Diabetes

Background: Arterial pulse pressure, the difference between systolic and diastolic blood pressure, has been used as an indicator (surrogate measure) of arterial stiffness. High arterial pulse pressure (> 40) has been associated with increased cardiovascular disease and mortality. Several clinical trials have reported that the proportion of calories from carbohydrate has an effect on blood pressure. The primary objective of this study was to assess arterial pulse pressure and its association with carbohydrate quantity and quality (glycemic load) with diabetes status for a Cuban American population. Methods: A single point analysis included 367 participants. There was complete data for 365 (190 with and 175 without type 2 diabetes). The study was conducted in the investigator’s laboratory located in Miami, Florida. Demographic, dietary, anthropometric and laboratory data were collected. Arterial pulse pressure was calculated by the formula systolic minus the diastolic blood pressure. Glycemic load, fructose, sucrose, percent of average daily calories from carbohydrate, fat and protein, grams of fiber and micronutrient intakes were calculated from a validated food frequency questionnaire. Results: The mean arterial pulse pressure was significantly higher in participants with (52.9 ± 12.4) than without (48.6 ± 13.4) type 2 diabetes. The odds of persons with diabetes having high arterial pulse pressure (>40) was 1.85 (95% CI =1.09, 3.13); p=0.023. For persons with type 2 diabetes higher glycemic load was associated with lower arterial pulse pressure. Conclusions: Arterial pulse pressure and diet are modifiable risk factors of cardiovascular disease. Arterial pulse pressure may be associated with carbohydrate intake differently considering diabetes status. Results may be due to individuals with diabetes following dietary recommendations. The findings of this study suggest clinicians take into consideration how medical condition, ethnicity and diet are associated with arterial pulse pressure before developing a medical nutrition therapy plan in collaboration with the client.

Phylloquinone (Vitamin K₁) Intake and Pulse Pressure as a Measure of Arterial Stiffness in Older Adults

This study examined the relationships among ethnicity/race, lifestyle factors, phylloquinone (vitamin K₁) intake, and arterial pulse pressure in a nationally representative sample of older adults from four ethnic/racial groups: non-Hispanic Whites, non-Hispanic Blacks, Mexican Americans, and other Hispanics. This was a cross-sectional study of U.S. representative sample with data from the National Health and Nutrition Examination Surveys, 2007-2008 and 2009-2010 of adults aged 50 years and older (N = 5296). Vitamin K intake was determined by 24-hour recall. Pulse pressure was calculated as the difference between the averages of systolic blood pressure and diastolic blood pressure. Compared to White non-Hispanics, the other ethnic/racial groups were more likely to have inadequate vitamin K₁ intake. Inadequate vitamin K₁ intake was an independent predictor of high arterial pulse pressure. This was the first study that compared vitamin K₁ inadequacy with arterial pulse pressure across ethnicities/races in U.S. older adults. These findings suggest that vitamin K screening may be a beneficial marker for the health of older adults.

External Validation of the ProACS Score for Risk Stratification of Patients with Acute Coronary Syndromes

INTRODUCTION: The ProACS risk score is an early and simple risk stratification score developed for all-cause in-hospital mortality in acute coronary syndromes (ACS) from a Portuguese nationwide ACS registry. Our center only recently participated in the registry and was not included in the cohort used for developing the score. Our objective was to perform an external validation of this risk score for short- and long-term follow-up. METHODS: Consecutive patients admitted to our center with ACS were included. Demographic and admission characteristics, as well as treatment and outcome data were collected. The ProACS risk score variables are age (≥72 years), systolic blood pressure (≤116 mmHg), Killip class (2/3 or 4) and ST-segment elevation. We calculated ProACS, Global Registry of Acute Coronary Events (GRACE) and Canada Acute Coronary Syndrome risk score (C-ACS) risk scores for each patient. RESULTS: A total of 3170 patients were included, with a mean age of 64±13 years, 62% with ST-segment elevation myocardial infarction. All-cause in-hospital mortality was 5.7% and 10.3% at one-year follow-up. The ProACS risk score showed good discriminative ability for all considered outcomes (area under the receiver operating characteristic curve >0.75) and a good fit, similar to C-ACS, but lower than the GRACE risk score and slightly lower than in the original development cohort. The ProACS risk score provided good differentiation between patients at low, intermediate and high mortality risk in both short- and long-term follow-up (p<0.001 for all comparisons). CONCLUSIONS: The ProACS score is valid in external cohorts for risk stratification for ACS. It can be applied very early, at the first medical contact, but should subsequently be complemented by the GRACE risk score.

The Relationship of Diet Quality and Blood Serum Lipid Levels in a Population at High Risk for Diabetes: The Strong Heart Family Study

Thesis (Master's)--University of Washington, 2016-08

Semiology versus laboratory approaches: comparison between interarm blood preassure differences and APOB/APOA ratio

Nowadays complementary diagnostic methods are replacing clinical examination and semiology is loosing space in our clinical practice. One of our main concerns in clinical practice is to assess Cardiovascular risk (CVR). And previous studies reported an increased CVR with a divergence of 10mmhg or more measured between both arms-interarm blood pressure difference (IAD)

Ratio of hemocomponents in massive transfusion and mortality of trauma patients in a university hospital

Background: Nowadays, there are very few studies about massive transfusion in our country. This situation generates the necessity to the elevation of possible new strategies to diminish mortality and its adverse effects. Material and methods: All massive transfusions were evaluated in a retrospective way from October 2010 to October 2012. All diagnosis groups were recorded and the patients were divided into three groups depending on the ratio between packed red blood cells (PRBC) and fresh frozen plasma (FFP) units (ratios ≤2, >2, and without FFP). Their mortality and/or survival were evaluated 30 days after as well as all the factors associated with the event. Results: A total of 69 patients were included (37 trauma patients, 28 gunshot wounds and 4 with lacerated wounds); the groups (ratios ≤2, >2, and no plasma at all) were distributed as follows: 30, 30 and 9 patients each, with an overall mortality rate of 60.8% within 30 days. A lower survival rate (12%) in the no plasma group (P=.015) was found and systolic blood pressure during transfusion had a mean of 67.7 mmHg (P=.012) in this group. Fresh frozen plasma units were 136 and 249 for >2 and ≤2 ratios respectively (P<.01); 85.5% of all patients developed metabolic acidosis during the transfusion, and the number of days in the hospital after the event had a mean of 24.5 days in all patients. Conclusions: High rates of massive transfusion mortality are still being reported in our ield. The use of transfusion strategies contribute to elevate the survival rate in patients with massive transfusion treatment