Anesthesia steady-state index: A combined measure of BIS, blood pressure and heart rate

2010 ◽  
Vol 27 ◽  
pp. 64
Author(s):  
A. Castro ◽  
C. S. Nunes ◽  
P. Amorim ◽  
F. Gomes de Almeida
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Steady State ◽  
State Index

Spectrum of orthostatic disorders: Classification based on an analysis of the short-term circulatory response upon standing

1991 ◽  
Vol 81 (2) ◽  
pp. 241-248 ◽  
Author(s):  
W. Wieling ◽  
A. D. J. ten Harkel ◽  
J. J. van Lieshout
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Steady State ◽  
Maximum Heart Rate ◽  
Circulatory Response ◽  
Group Iii ◽  
Additional Information ◽  
Postural Tachycardia ◽  
Group I ◽  
Circulatory Control

1. In 31 consecutively referred patients (20 females, 11 males) with overt or suspected orthostatic disorders, the changes in blood pressure and heart rate that occur in the first 2 min of standing were analysed. 2. Blood pressure was measured continuously by Finapres. The blood pressure and heart rate responses after 1–2 min of standing (early steady-state response) were used to classify the patients as follows: group I (n = 17, age 42 ± 17 years), normal early steady-state blood pressure and heart rate responses; group II (n = 5, age 40 ± 14 years), combination of normal early steady-state blood pressure and postural tachycardia; group III (n = 9, age 51 ± 14 years), hypotensive orthostatic response with (4/9) or without (5/9) postural tachycardia. We examined whether additional information could be obtained by beat-to-beat analysis of the initial circulatory response (first 30 s). It was quantified by identifying the blood pressure trough and overshoot and the maximum heart rate and relative bradycardia. 3. The initial drop in systolic and diastolic blood pressures did not differ between the three groups. A recovery of blood pressure with a systolic and/or diastolic blood pressure overshoot was present in all group I and II patients, but was absent in all except two patients in group III. The initial maximum heart rate increase did not differ between the three groups. The relative bradycardia was less in groups II and III than in group I. 4. We conclude that analysis of the beat-to-beat blood pressure changes in the first 30 s after the onset of standing provides almost all the information that is necessary to determine abnormalities in orthostatic circulatory control.

Circulatory adaptation to orthostatic stress in healthy 10–14-year-old children investigated in a general practice

1991 ◽  
Vol 81 (1) ◽  
pp. 51-58 ◽  
Author(s):  
J. H. A. Dambrink ◽  
B. P. M. Imholz ◽  
J. M. Karemaker ◽  
W. Wieling
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Steady State ◽  
Initial Phase ◽  
Time Course ◽  
Free Standing ◽  
Postural Tachycardia ◽  
Circulatory Control ◽  
Head Up Tilt ◽  
Blood Pressures

1. The magnitude and time course of circulatory adaptation to active standing were investigated in healthy premenarchic girls and boys (n = 24; 10–14 years old) by non-invasive measurement of heart rate and continuous finger blood pressure (Finapres). 2. Four subjects (two girls, two boys) showed presyncopal symptoms after 4–9 min of free standing. 3. In the 20 non-fainting subjects, changes in blood pressure and heart rate upon standing did not differ between girls (n = 10) and boys (n = 10). In the initial phase of standing (first 30 s) systolic and diastolic blood pressures dropped by 22 ± 14 (mean ± sd) and 16 ± 7 mmHg, respectively, at 8 ± 2 s. Blood pressure subsequently recovered and showed an overshoot in all subjects. The transient drop in blood pressure was accompanied by an increase in heart rate of 40 ± 7 beats/min. These characteristic transient changes were not observed with passive head-up tilt. During the early steady-state phase (2 min), systolic blood pressure was similar to the supine value and diastolic blood pressure rose by 11 ± 5 mmHg. Heart rate increased by 25 ± 11 beats/min. In six of the subjects (three girls, three boys) the increase in heart rate exceeded 30 beats/min (postural tachycardia). Little further changes were observed during prolonged (10 min) standing. 4. Typical findings in the four near-fainting subjects were higher supine heart rates, no blood pressure overshoot in the initial phase (in three out of four subjects), postural tachycardia in the early steady-state phase and progressive decreases in blood pressure and heart rate afterwards. 5. In conclusion, for investigation of orthostatic circulatory adaptation in childhood it is important to pay attention to the dynamics of the circulatory response. No important differences appear to exist in orthostatic circulatory control between premenarchic girls and boys: orthostatic tachycardia and fainting appear to be common in both.

Cardiovascular and Metabolic Responses to On-Water Upwind Sailing in Optimist Sailors

2016 ◽  
Vol 11 (5) ◽  
pp. 615-622
Author(s):  
Santiago Lopez ◽  
Jan G. Bourgois ◽  
Enrico Tam ◽  
Paolo Bruseghini ◽  
Carlo Capelli
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Steady State ◽  
Exercise Intensity ◽  
Peripheral Resistance ◽  
Peak Oxygen Uptake ◽  
Metabolic Responses ◽  
Arterial Blood ◽  
The Individual

Purpose:To explore the cardiovascular and metabolic responses of 9 Optimist sailors (12.7 ± 0.8 y, 153 ± 9 cm, 41 ± 6 kg, sailing career 6.2 ± 1 y, peak oxygen uptake [V̇O2peak] 50.5 ± 4.5 mL · min−1 · kg−1) during on-water upwind sailing with various wind intensities (W).Methods:In a laboratory session, peak V̇O2, beat-by-beat cardiac output (Q̇), mean arterial blood pressure (MAP), and heart rate (fH) were measured using a progressive cycle ramp protocol. Steady-state V̇O2, Q̇, MAP, and fH at 4 submaximal workloads were also determined. During 2 on-water upwind sailing tests (constant course and with tacks), W, Q̇, MAP, and fH were measured for 15 min. On-water V̇O2 was estimated on the basis of steady-state fH measured on water and of the individual ΔV̇O2/ΔfH relationship obtained in the laboratory.Results:V̇O2, fH, and Q̇ expressed as percentage of the corresponding peak values were linearly related with W; exercise intensity during on-water sailing corresponded to 46–48% of V̇O2peak. MAP and total vascular peripheral resistance (TPR = MAP/Q̇) were larger (P < .005) during on-water tests (+39% and +50%, respectively) than during cycling, and they were correlated with W. These responses were responsible for larger values of the double (DP) and triple (TP) products of the heart during sailing than during cycling (P < .005) (+37% and +32%, respectively).Conclusions:These data indicate that the cardiovascular system was particularly stressed during upwind sailing even though the exercise intensity of this activity was not particularly high.

Effect of acute ethanol administration on the baroreceptor reflex control of heart rate in normotensive human volunteers

1987 ◽  
Vol 72 (1) ◽  
pp. 113-122 ◽  
Author(s):  
A.-R. A. Abdel-Rahman ◽  
R. H. Merrill ◽  
W. R. Wooles
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Steady State ◽  
Baroreflex Sensitivity ◽  
Baroreceptor Reflex ◽  
Ethanol Administration ◽  
Steady State Method ◽  
Acute Ethanol ◽  
Reflex Control ◽  
Baroreceptor Reflex Control

1. The effects of acute ethanol administration on blood pressure, heart rate and the baroreceptor reflex control of heart rate were studied in normotensive subjects who served as their own control. Baroreceptor reflex control of heart rate was measured by two methods: the ramp method and the steady state method. 2. None of the doses of ethanol had any effect on blood pressure during the observation period, except for the highest dose where a slight elevation was evident for a short period of time. On the other hand, the heart rate showed a slight but consistent dose-related increase. 3. In general, ethanol attenuated the baroreceptor mediated bradycardia but this effect was dependent on the way in which blood presure was elevated. A dose-related impairment of baroreceptors was evident when the ramp method was used, i.e. ethanol significantly depressed baroreflex sensitivity, expressed as Δheart period (HP)/Δmean arterial pressure (MAP). In contrast, ΔHP/ΔMAP was not influenced by ethanol when the steady state method was used. However, the steady state baroreflex curves were reset about a higher median blood pressure (MAP50), suggesting that the baroreceptors will be operative at higher blood pressure levels after ethanol. 4. The pressor responsiveness was also influenced differently by ethanol depending on the method of injecting phenylephrine. An increase in pressor responsiveness was evident, though not dose-related, after ethanol only when blood pressure was elevated by the ramp method, suggesting that the inverse relationship between baroreflex sensitivity and pressor responsiveness is more prominent with the ramp method and/or when impairment rather than resetting of baroreceptors occurs. 5. That the decrease in baroreflex sensitivity and the increase in MAP50 were related to peak ethanol levels in blood and that the blood pressure was not influenced by ethanol strongly suggest these effects were ethanol mediated. The weakened buffering action of the baroreflexes would be expected to favour the development of higher blood pressure.

Nonuniform enhancement of baroreflex sensitivity by atrial natriuretic peptide in conscious rats and dogs

1994 ◽  
Vol 267 (3) ◽  
pp. R678-R686 ◽  
Author(s):  
R. L. Woods ◽  
C. A. Courneya ◽  
G. A. Head
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Steady State ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Baroreflex Sensitivity ◽  
Conscious Rats ◽  
Afferent Activation ◽  
Chronically Instrumented Dogs ◽  
Atrial Natriuretic

The influence of atrial natriuretic peptide (ANP) on the blood pressure (BP)-heart rate (HR) baroreflex was studied in conscious chronically instrumented dogs and rats. In both species, sigmoid steady-state baroreflex curves were constructed from the baroreflex changes in HR to alternating slow injections of vasopressor and vasodepressor drugs. When this method was used in dogs, ANP caused a small but significant (P < 0.05) enhancement of the sensitivity (22 +/- 10%) and curvature (26 +/- 10%) of the baroreflex, which was without a change in HR range. In rats, ANP had no significant effect on any baroreflex parameter derived from steady-state curves. By contrast, in the same rats, fast reflex HR responses to rapid increases in BP (ramp) exposed a substantial (81 +/- 21%) ANP-induced enhancement of baroreflex sensitivity. Contribution from arterial vs. nonarterial afferents to the baroreflex is not uniform between these two techniques (steady state reflects largely arterial baroreceptor input, ramp evokes a greater proportion of cardiopulmonary afferent activation). The present study demonstrated that baroreceptor HR reflex responses to ANP depend on the baroreflex techniques employed and probably exposed a selectivity by ANP for nonarterial baroreflex pathways.

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