scholarly journals PREDICTION OF CRITICAL INCIDENT DURING EPIDURAL ANESTHESIA IN GYNECOLOGICAL PATIENTS

2017 ◽  
Vol 11 (2) ◽  
pp. 98-105
Author(s):  
Maria V. Golovataya
Keyword(s):  
Epidural Anesthesia ◽  
Critical Incident ◽  
Critical Incidents ◽  
Elective Surgery ◽  
Postoperative Nausea And Vomiting ◽  
Early Postoperative Period ◽  
Frequency Of Occurrence ◽  
Group 2 ◽  
Peripheral Chemoreflex ◽  
Group 1

Objective - to estimate frequency of occurrence of critical incidents during epidural anesthesia in gynecological patients with different sensitivity of peripheral chemoreflex. Material and Methods: prospective observational blind study, 54 gynecological patients, elective surgery. The day before the surgery, the sensitivity of peripheral chemoreflex was determined by the duration of an arbitrary threshold apnea in a test with a delayed respiration. According to the duration of the test, the patients were divided into groups: high (group «1») and medium (group «2») sensitivity of peripheral chemoreflex. During the operation and in the early postoperative period, critical incidents were recorded. Results and Conclusion(s). During epidural anesthesia in gynecological patients from intraoperative critical incidents is revealed hypotension. The frequency of occurrence of hypotension was 32.1% in patients of group «1» and 15.4% in patients of group «2». High sensitivity of peripheral chemoreflex in patients during epidural anesthesia is a predictor of unstable hemodynamics, as well as the risk of postoperative nausea and vomiting.

scholarly journals COMPARISON OF LEVOBUPIVACAIN AND ROPIVAKAIN IN COMBINED ANESTHESIA IN ONCOGNECOLOGICAL INTERVENTIONS

2018 ◽  
Vol 12 (2) ◽  
pp. 118-124
Author(s):  
Kirill A. Tsygankov ◽  
R. E Lakhin ◽  
A. V Schegolev ◽  
A. D Khalikov ◽  
V. V Mordovin ◽  
...  
Keyword(s):  
Epidural Anesthesia ◽  
Postoperative Period ◽  
Critical Incident ◽  
Critical Incidents ◽  
Pain Syndrome ◽  
Maximum Level ◽  
Sensory Block ◽  
Sensory Response ◽  
Group 2 ◽  
Group 1

The aim of the study was to evaluate the nature of the development of the sensory block and the frequency of occurrence of critical incidents during anesthesia, in the immediate postoperative period using levobupivacaine and ropivacaine in patients with an oncogynecological profile. Materials and methods. The study included 48 women who were randomized into two groups of 24 patients each, depending on the anesthetic used: group 1 - ropivacaine, group 2 - levobupivacaine. The latent period of the sensory block, the motor block, the maximum level of development of the sensory block after 15 minutes, critical incidents at the stages of anesthesia, the level of the pain syndrome after extubation and coughing were analyzed in the groups. Results. The sensory response to the cold sample, after the administration of local anesthetics in the groups, differed: in the first group, 300 (241.25, 314.75) s, in the second group 54.5 (45.75, 60.25) s. The maximum level of the sensory block in the groups was different. During the induction and maintenance of anesthesia, the most common critical incident was hypotension. Reduction of systolic blood pressure for the induction of anesthesia in group 1 was detected in 6 (25%) cases, in group 2 in 7 (29%). After extubation, the pain syndrome in the first group was 1.7 (1; 6), in the second group 1.7 (1; 4). With a cough, the assessment of the pain syndrome had the same intensity of pain, both in the first and in the second group 2 (1; 3). Conclusions. Levobupivacaine with epidural anesthesia accelerates the development of the sensory block. The maximum level of the sensory block does not differ with the use of levobupivacaine and ropivacaine. Hypotension in the stages of anesthesia is a frequent critical incident in epidural anesthesia. The severity of the pain syndrome during extubation and in the immediate postoperative period does not depend on the selected anesthetic.

Usage of 25% albumin solution in the intraoperative and early postoperative periods of liver transplantation from a cadaveric donor.

2021 ◽  
Author(s):  
С.В. Журавель ◽  
Н.К. Кузнецова ◽  
В.Э. Александрова ◽  
П.В. Гаврилов ◽  
А.М. Талызин ◽  
...  
Keyword(s):  
Liver Transplantation ◽  
Postoperative Period ◽  
Human Albumin ◽  
Early Postoperative Period ◽  
Hemodynamic Parameters ◽  
Albumin Solution ◽  
Transfusion Therapy ◽  
Group 2 ◽  
Human Albumin Solution ◽  
Group 1

Введение. Терапевтическое использование раствора человеческого альбумина у пациентов в периоперационном периоде трансплантации печени (ТП) представляет интерес в контексте осложнений и исходов операции. Цель исследования: оценить влияние интраоперационной трансфузии 25% раствора человеческого альбумина на течение раннего послеоперационного периода при ортотопической ТП от посмертного донора. Материалы и методы. В исследование включены 47 пациентов, которым была выполнена трупная ТП. Были сформированы 2 группы: пациенты группы 1 (n = 21) получали трансфузию 25% раствора человеческого альбумина в конце операции ТП и через 24 ч после операции; пациенты группы 2 (n = 26) получали трансфузию 25% раствора человеческого альбумина в первые сутки послеоперационного периода. Осуществляли контроль лабораторных параметров крови пациента перед началом оперативного вмешательства, через 24 ч и через 48 ч после операции. Интраоперационно оценивали значения систолического (САД) и диастолического (ДАД) артериального давления, частоту сердечных сокращений (ЧСС), дозу вазопрессоров, объем инфузионно-трансфузионной терапии, кровопотерю и диурез. В послеоперационном периоде фиксировали возможные осложнения, проведенные сеансы заместительной почечной терапии (ЗПТ), а также количество дней в стационаре. Результаты. Оценка значений САД, ДАД и ЧСС в начале и конце операции показала достоверно лучшие показатели гемодинамики и снижение дозировок вазопрессорной поддержки в конце вмешательства в группе 1 по сравнению с группой 2 (p < 0,05). В послеоперационном периоде инфекционные осложнения зарегистрированы у одного пациента группы 1 и у трех пациентов группы 2. Проведение ЗПТ потребовалось двум пациентам из группы 2. Все пациенты обеих групп были выписаны из стационара, при этом число дней госпитализации в группе 2 было статистически значимо больше по сравнению с пациентами группы 1: 26,9 ± 3,9 против 17,2 ± 4,3 (p < 0,05). Заключение. Интраоперационная инфузия 25% раствора альбумина позволяет стабилизировать показатели гемодинамики в конце операции ТП, снизить потребность в кардиотонической поддержке и сократить время госпитализации у пациентов после ТП. Background. The therapeutic use of human albumin solution in patients in the perioperative period of liver transplantation (LT) is of interest in the context of complications and outcomes of surgery. Objectives: to assess the effect of intraoperative transfusion of 25% human albumin solution on the early postoperative period in orthotopic LT from a postmortem donor. Patients/Methods. The study included 47 patients who underwent cadaveric LT. Two groups were formed: patients in group 1 (n = 21) received transfusion of 25% human albumin solution at the end of LT and 24 hours after surgery; patients in group 2 (n = 26) received transfusion of 25% human albumin solution on the first day of the postoperative period. The laboratory parameters of the patient’s blood were monitored before surgery, 24 hours later, and 48 hours after surgery. Intraoperatively, the values of systolic (SBP) and diastolic (DBP) blood pressure, heart rate (HR), dose of vasopressors, volume of infusion- transfusion therapy, blood loss and diuresis were assessed. In the postoperative period, possible complications, renal replacement therapy (RRT) sessions performed, and the number of days in the hospital were recorded. Results. Assessment of SBP, DBP and HR values showed significantly better hemodynamic parameters and reduced dosages of vasopressor support at the end of surgery in group 1 compared to group 2 (p < 0.05). In the postoperative period, infectious complications were registered in one patient of group 1 and in three patients of group 2. Two patients from group 2 required RRT. All patients were discharged from the hospital, while the number of hospitalization days in group 2 was statistically significantly greater than in patients in group 1: 26.9 ± 3.9 versus 17.2 ± 4.3 (p < 0.05). Conclusions. Intraoperative infusion of 25% albumin solution allows stabilizing hemodynamic parameters at the end of LT surgery, reducing the need for cardiotonic support and shortening the hospitalization time in patients after LT.

scholarly journals Effect of anterior capsular polishing on the incidence of YAG capsulotomy

2016 ◽  
Vol 11 (3) ◽  
Author(s):  
Muhammad A Ahad ◽  
Mohammad Rashad Qamar ◽  
Sameh K Hindi ◽  
Martin N Kid
Keyword(s):  
Outcome Measure ◽  
Early Postoperative Period ◽  
Controlled Study ◽  
Control Group ◽  
Anterior Capsule ◽  
Main Outcome Measure ◽  
Group I ◽  
Group 2 ◽  
One Year ◽  
Group 1

Purpose: To study the effect of anterior capsule polishing during phacoemulsification on the incidence of post operative YAG laser capsulotomy. Method: A retrospective controlled study of 159 patients who underwent uncomplicated phacoemulsification with anterior capsular polishing between October 1998 and March 2000. 169 age matched patients who underwent phacoemulsification but without anterior capsule polishing served as controls. Main outcome measure: Incidence of visually significant YAG capsulotomy, which improved the Snellen acuity for more than 1 line or at least 1 line with subjective improvements in symptoms. Results: 2.51 % of patients with anterior capsular polishing (Group 1) had YAG capsulotomy compared to 7.1% of patients in control group at one year. However, after two years, 11.3% of patients in Group I had YAG capsulotomy compared to 12.4% in Group 2. Conclusion: Anterior capsular polishing during cataract surgery may delay the opacification of posterior capsule during the early postoperative period. But does not decrease the incidence of YAG capsulotomy after two years.

scholarly journals Evaluation of the Accuracy of the Delta Life DL 1000 Oscillometric Monitor for Blood Pressure Measurement in Anesthetized Dogs of Different Weight Ranges

2020 ◽  
Vol 48 ◽  
Author(s):  
Bárbara Silva Correia ◽  
Eduardo Raposo Monteiro ◽  
João Victor Barbieri Ferronatto ◽  
Luciana Branquinho Queiroga ◽  
José Ricardo Herrera Becerra
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Pressure Measurement ◽  
Elective Surgery ◽  
Blood Pressure Measurement ◽  
Measurement Data ◽  
Arterial Blood ◽  
Anesthetized Dogs ◽  
Group 2 ◽  
Group 1

Background: Arterial blood pressure is one of the most commonly variables monitored during anesthetic procedures in veterinary patients. The most reliable method for measuring arterial blood pressure in dogs and cats is the direct (invasive) method. However, the oscillometric method is less complex and more practical for clinical routine in small animals. Nevertheless, oscillometric monitors present great variability in accuracy. The present study aimed to determine the accuracy of the Delta Life DL 1000 oscillometric monitor for measurement of systolic, mean and diastolic blood pressures (SAP, MAP and DAP, respectively) in anesthetized dogs of different weight ranges.Materials, Methods & Results: This study was approved by the Institutional Ethics Committee of Animal Use. Fifteen female dogs of different breeds, weighing 11.6 ± 10.0 kg and with a mean age of 48 ± 51 months were used. All animals were scheduled for elective surgery under general anesthesia in the Institution Veterinary Hospital. Dogs were anesthetized with morphine, propofol and isoflurane and had one 20 or 22 gauge catheter introduced into the dorsal pedal artery for continuous, invasive monitoring of SAP, MAP and DAP. A blood pressure cuff was positioned over the middle third of the radius and connected to Delta Life DL 1000 monitor. Oscillometric readings of SAP, MAP and DAP were registered every 5 minutes, and invasive values were simultaneously recorded. Values obtained with both methods were compared (invasive versus oscillometric) by use of the Bland Altman method to determine the bias, standard deviation of bias and 95% limits of agreement. The percentages of errors between the methods within 10 mmHg and within 20 mmHg were calculated. The results obtained were compared with the criteria from the American College of Veterinary Internal Medicine (ACVIM) for validation of indirect methods of arterial blood pressure measurement. Data were stratified into two groups according to the weight: < 10 kg (Group 1; n = 9); and ≥ 10 kg (Group 2; n = 6). In Group 1, 119 paired measurements were obtained, four of which classified as hypotension (SAP < 90 mmHg), 98 as normotension (SAP from 90 to 140mmHg) and 17 as hypertension (SAP > 140 mmHg). Bias (± SD) values in Group 1 were as follows: SAP, 5.2 ± 18.1 mmHg; MAP, -3.4 ± 17.2 mmHg; and DAP, 12.0 ± 17.5 mmHg. The percentages of errors within 10 mmHg were 40.3% for SAP; 45.4% for MAP and 28.6% for DAP. The percentages of errors within 20 mmHg were 72.3% for SAP, 84.0% for MAP and 68.1% for DAP. In Group 2, 66 paired measurements were obtained, nine of which classified as hypotension, 56 as normotension and one as hypertension. Bias (± SD) in Group 2 were as follows: SAP, 13.6 ± 14.3 mmHg; MAP, -1.1 ± 13.5 mmHg; and DAP, 8.2 ± 16.0 mmHg. The percentages of errors within 10 mmHg were 33.3% for SAP, 77.3% for MAP and 33.3% for DAP. The percentages of errors within 20 mmHg were 65.1% for SAP, 92.4% for MAP and 83.4% for DAP.Discussion: Based on the results of this study and reference criteria from the ACVIM, the Delta Life DL 1000 monitor had a poor accuracy for SAP, MAP and DAP and did not meet the criteria from the ACVIM in anesthetized dogs under 10 kg. Measurements of MAP in dogs ≥ 10 kg met the ACVIM criteria, but measurements of SAP and DAP did not. Based on the findings in this study, the DL 1000 oscillometric monitor is not recommended for blood pressure measurement in anesthetized dogs < 10 kg. In dogs ≥ 10 kg, measurements of MAP yielded acceptable values, but SAP and DAP measurements did not.

scholarly journals Effect of Cap-Lenticule Diameter Difference on the Visual Outcome and Higher-Order Aberrations in SMILE: 0.4 mm versus 1.0 mm

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Banu Torun Acar ◽  
Suphi Acar
Keyword(s):  
Visual Acuity ◽  
Visual Outcome ◽  
Higher Order ◽  
Early Postoperative Period ◽  
Higher Order Aberrations ◽  
Corrected Distance Visual Acuity ◽  
Lenticule Extraction ◽  
Group 2 ◽  
Group 1

Purpose. To evaluate the effect of cap-lenticule diameter difference (CLDD) on the visual outcome and higher-order aberrations (HOAs) of small-incision lenticule extraction (SMILE). Methods. A total of 132 patients who had bilateral SMILE for myopia or myopic astigmatism were included. The CLDD was 0.4 mm in 54 patients (group 1) and 1.0 mm in 78 patients (group 2). The refractive parameters, uncorrected (UDVA) and corrected distance visual acuity (CDVA), and HOAs were determined preoperatively and during six months follow-up. Results. Group 1 had better CDVA (in logMAR) compared to group 2 at day 1 (−0.07 ± 0.07 versus 0.04 ± 0.07, resp.; p<0.001) and week 1 (−0.07 ± 0.07 versus –0.04 ± 0.07, resp.; p=0.001). The visual acuity improved more in group 1 than in group 2. The UDVA (in logMAR) was 0.07 ± 0.07 and 0.29 ± 0.09 at day 1 (p<0.001) and −0.08 ± 0.07 and −0.06 ± 0.06 at six months (p=0.038) in group 1 and group 2, respectively. Group 1 was associated with significantly less induction of HOAs (0.24 ± 0.08 μm and 0.32 ± 0.26 μm, resp.; p=0.002). Conclusions. In SMILE, 0.4 mm CLDD is associated with better visual outcome and less induction of HOAs than 1.0 mm. Narrow CLDD should be considered in SMILE to increase the visual acuity particularly in the early postoperative period.

scholarly journals Karyotype Reorganization in Wheat–Rye Hybrids Obtained via Unreduced Gametes: Is There a Limit to the Chromosome Number in Triticale?

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2052
Author(s):  
Olga G. Silkova ◽  
Yulia N. Ivanova ◽  
Dina B. Loginova ◽  
Lilia A. Solovey ◽  
Elena A. Sycheva ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Unreduced Gametes ◽  
Frequency Of Occurrence ◽  
Robertsonian Translocations ◽  
Meiotic Restitution ◽  
Group 3 ◽  
Group 2 ◽  
Few Data ◽  
Diploid Gametes ◽  
Group 1

To date, few data have been accumulated on the contribution of meiotic restitution to the formation of Triticum aestivum hybrid karyotypes. In this study, based on FISH and C-banding, karyotype reorganization was observed in three groups of F5 wheat–rye hybrids 1R(1A) × R. Aberrations, including aneuploidy, telocentrics, and Robertsonian translocations, were detected in all groups. Some of the Group 1 plants and all of the Group 2 plants only had a 4R4R pair (in addition to 1R1R), which was either added or substituted for its homeolog in ABD subgenomes. In about 82% of meiocytes, 4R4R formed bivalents, which indicates its competitiveness. The rest of the Group 1 plants had 2R and 7R chromosomes in addition to 1R1R. Group 3 retained all their rye chromosomes, with a small aneuploidy on the wheat chromosomes. A feature of the meiosis in the Group 3 plants was asynchronous cell division and omission of the second division. Diploid gametes did not form because of the significant disturbances during gametogenesis. As a result, the frequency of occurrence of the formed dyads was negatively correlated (r = −0.73) with the seed sets. Thus, meiotic restitution in the 8n triticale does not contribute to fertility or increased ploidy in subsequent generations.

scholarly journals Multimodal Low-opioid Anesthesia as an Effective Way to Prevent Postoperative Nausea and Vomiting. Pathophysiological Aspects of this Complication

2021 ◽  
Vol 6 (1) ◽  
pp. 101-106
Author(s):  
Т. Ovsiienko ◽  
◽  
M. Bondar ◽  
O. Loskutov ◽  
◽  
...  
Keyword(s):  
General Anesthesia ◽  
Postoperative Nausea ◽  
Postoperative Nausea And Vomiting ◽  
Nausea And Vomiting ◽  
Control Group ◽  
Average Dose ◽  
Kidney Surgery ◽  
Group 2 ◽  
Total Average ◽  
Group 1

Postoperative nausea and vomiting are common adverse effects of anaesthesia and surgery. Up to 80% of patients may be affected. These outcomes are a major cause of patient dissatisfaction. In addition, postoperative nausea and vomiting can independently cause the occurrence of rather serious complications of the postoperative period, such as aspiration of gastric contents into the airways, hemodynamic disorders in patients with a compromised cardiovascular system, failure of surgical sutures, bleeding, dehydration and electrolyte imbalance which ultimately can lead to disability of patients, prolongation of their hospitalization and higher treatment costs. Material and methods. The paper presents the results of our own research on the use of multimodal low-opioid general anesthesia as one of the methods for the prevention of postoperative nausea and vomiting during anesthetic provision of laparoscopic kidney surgery. The study involved 38 patients who underwent laparoscopic kidney surgery. Results and discussion. To compare the incidence of postoperative nausea and vomiting, patients were randomly divided into two groups. Group 1 used multimodal general anesthesia with standard opioid doses, while group 2 used multimodal low-opioid general anesthesia. The total average dose of fentanyl that was used during the entire time of anesthesia in the control group was 373.3 ± 50.8 μg (4.34 μg / kg / h). The total average dose of fentanyl that was used during the entire time of anesthesia in the study group was 217.39 ± 49.1 μg (1.76 μg / kg / h). In group 1, vomiting occurred in 4 patients out of 15 in the postoperative period, in group 2 there were 4 patients with vomitting, but out of 23 operated patients. The standardized rate of postoperative nausea and vomiting in the control group was 26.6%, in the main group it was 17.3%. Conclusion. As a result of comparing the incidence of postoperative nausea and vomiting in patients of both study groups, we found that a decrease in the dose of perioperative use of opioids helps to reduce the incidence of this complication, which increased the safety of anesthetic management, greatly facilitated and accelerated the rehabilitation of patients after laparoscopic kidney surgery. The work also highlighted and systematized information on the morphology of structures involved in the formation of postoperative nausea and vomiting, on the physiology of this process

scholarly journals COVID-19 and antibacterial therapy in the inpatient settings: to whom, when, why?

2021 ◽  
Vol 31 (6) ◽  
pp. 701-709
Author(s):  
Nina A. Karoli ◽  
Alena V. Aparkina ◽  
Elena V. Grigoryeva ◽  
Nadezhda A. Magdeeva ◽  
Natalia M. Nikitina ◽  
...  
Keyword(s):  
Bacterial Infection ◽  
Elective Surgery ◽  
Unintended Consequences ◽  
Hospitalized Patients ◽  
Fourth Generation ◽  
Treatment Regimens ◽  
Inpatient Settings ◽  
Group 2 ◽  
To Receive ◽  
Group 1

Although antibiotics (ABs) are ineffective against COVID-19, they are often prescribed to patients with the new coronavirus infection. Many of these prescriptions are uncalled for.The aim of the work is to assess the frequency of prescribing antibiotics to hospitalized patients with confirmed COVID-19, identify the most commonly prescribed ABs, and determine the significance of various biomarkers for the diagnosis of bacterial infection.Methods. A retrospective analysis of 190 inpatient cases with confirmed COVID-19 was carried out. The records of COVID-19 patients who were admitted to the intensive care unit were excluded from the analysis. Two groups were formed: 30 patients (group 1) with COVID-19, emergency or elective surgery, and exacerbation of chronic infectious diseases, and 160 patients (group 2) with manifestations of COVID-19 only.Results. ABs were prescribed to 189 patients upon admission to the hospital. The most frequently prescribed ABs included macrolides (63.5%), respiratory fluoroquinolones (49.7%), and third or fourth-generation cephalosporins (57.1%). ABs were administered starting from the first day of admission and until the discharge. The patients in group 2 were more often prescribed respiratory fluoroquinolones and, less often, III - IV generation cephalosporins. Moreover, macrolides were used in the treatment regimens of both groups. Longer administration of respiratory fluoroquinolones to patients in group 2 than patients in group 1 (p < 0,05) was noted. Group 2 also tended to receive longer therapy with macrolides. On admission, the patients with signs of bacterial infection had more significant leukocytosis with a neutrophilic shift, a more common increase in ESR of more than 20 mm/h and an increase in the level of procalcitonin > 0,5 ng/ml.Conclusion. ABs were administered to the overwhelming majority of hospitalized patients in the absence of clear therapeutic indications. The ABs are likely to have a minimal benefit as empirical treatment of COVID-19 and are associated with unintended consequences, including adverse effects and increased antibiotic resistance. According to our data, the most informative markers of a secondary bacterial infection in patients with COVID-19 are leukocytosis with a neutrophilic shift, an increase in ESR of more than 20 mm/h, and a procalcitonin level of more than 0,5 ng/ml.

scholarly journals Pathomorphology of adaptive changes in the remaining kidney in the early postoperative period after nephrectomy

2020 ◽  
Vol 10 (1) ◽  
pp. 19-24
Author(s):  
Igor Sergeevich Shormanov ◽  
Marina S. Los ◽  
Maxim V. Kosenko ◽  
Natalia S. Shormanova
Keyword(s):  
Postoperative Period ◽  
Morphological Changes ◽  
Renal Tissue ◽  
Early Postoperative Period ◽  
Left Group ◽  
White Rats ◽  
Group 3 ◽  
Group 2 ◽  
Single Kidney ◽  
Group 1

Objective. To study the adaptive capacity of a single remaining kidney in the early postoperative period of nephrectomy in an experiment. Materials and methods. The experiment involved 35 laboratory white rats, which were divided into three experimental groups. Group 1 (n = 5) intact animals, group 2 (n = 15) animals underwent nephrectomy on the left; group 3 (n = 15) animals underwent nephrectomy and additionally were created 90 minute hypoxic hypoxia. Histological material was collected on the 5th, 21st and 60th days after surgery. Results. Characteristic morphological changes in the only remaining kidney were an increase in the size of the glomeruli and a decrease in their number. Nephron fibrosis was detected, accompanied by increased production of antigens by the tubular epithelium, which is likely a response to a cascade increase in oxidative stress and increased release of cytokines that stimulate the production of intrarenal collagen. Conclusion. Nephrectomy and hypoxia are provocateurs for the development of systemic distress syndrome, the result of which is the formation of a vicious pathogenetic circle, which reduces the functionality of the renal tissue. This can be considered as one of the early preclinical mechanisms for the initiation of single kidney disease in the future.

Rating Visual Velocities: Presentation Order versus Frequency of Occurrence

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 363-363
Author(s):  
A N Sokolov ◽  
W H Ehrenstein ◽  
M A Pavlova
Keyword(s):  
Order Effect ◽  
Frequency Theory ◽  
Presentation Order ◽  
Frequency Effect ◽  
Frequency Of Occurrence ◽  
Frequency Distributions ◽  
Frequency Effects ◽  
Consistency Model ◽  
Group 2 ◽  
Group 1

Given equal frequencies of occurrence of stimuli, identical velocities receive higher or lower ratings depending on whether slow or fast velocities happen to occur on the early trials of a run (Ehrenstein and Sokolov, 1996 Perception25 Supplement, 34 – 35). When stimuli vary in their frequency of occurrence, this presentation-order effect might enhance or substitute the well-known frequency effect (Parducci's range - frequency theory) on category ratings. The aim of the present study was to contrast these two effects for ratings of visual velocities. Two groups of observers had to rate five stimulus velocities (3, 4.5, 6, 7.5, and 9 deg s−1) of a single luminous dot using three categories (slow, medium, fast). Respective frequencies of occurrence for these velocities were either 4 - 4 - 8 - 14 - 20 (group 1, negative skewing for frequency) or 20 - 14 - 8 - 4 - 4 (group 2, positive skewing). The quasi-random presentation order of each set, on the contrary, corresponded to either positively skewed (group 1) or negatively skewed (group 2) frequency distributions. No significant differences in the ratings of two groups (other than a slight preference for the presentation-order effect beyond 6 deg s−1) were found, as if the presentation order and frequency effects had cancelled each other. This suggests that the presentation order of velocities is at least as powerful as their frequency of occurrence. Lack of agreement between our results and predictions of computer-simulated Haubensak's consistency model as well as of Parducci's range - frequency theory requires a model which accounts for an interaction of the two effects.

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