scholarly journals Testing individual baroreflex responses to hypoxia-induced peripheral chemoreflex stimulation

2020 ◽  
Vol 30 (6) ◽  
pp. 531-540
Author(s):  
Hendrik Kronsbein ◽  
Darius A. Gerlach ◽  
Karsten Heusser ◽  
Alex Hoff ◽  
Fabian Hoffmann ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Pressor Response ◽  
Human Subjects ◽  
Arterial Oxygen Saturation ◽  
Recovery Period ◽  
Arterial Oxygen ◽  
Heart Rate Regulation ◽  
Peripheral Chemoreflex ◽  
Collective Influence

Abstract Introduction Baroreflexes and peripheral chemoreflexes control efferent autonomic activity making these reflexes treatment targets for arterial hypertension. The literature on their interaction is controversial, with suggestions that their individual and collective influence on blood pressure and heart rate regulation is variable. Therefore, we applied a study design that allows the elucidation of individual baroreflex–chemoreflex interactions. Methods We studied nine healthy young men who breathed either normal air (normoxia) or an air–nitrogen–carbon dioxide mixture with decreased oxygen content (hypoxia) for 90 min, with randomization to condition, followed by a 30-min recovery period and then exposure to the other condition for 90 min. Multiple intravenous phenylephrine bolus doses were applied per condition to determine phenylephrine pressor sensitivity as an estimate of baroreflex blood pressure buffering and cardiovagal baroreflex sensitivity (BRS). Results Hypoxia reduced arterial oxygen saturation from 98.1 ± 0.4 to 81.0 ± 0.4% (p < 0.001), raised heart rate from 62.9 ± 2.1 to 76.0 ± 3.6 bpm (p < 0.001), but did not change systolic blood pressure (p = 0.182). Of the nine subjects, six had significantly lower BRS in hypoxia (p < 0.05), two showed a significantly decreased pressor response, and three showed a significantly increased pressor response to phenylephrine in hypoxia, likely through reduced baroreflex buffering (p < 0.05). On average, hypoxia decreased BRS by 6.4 ± 0.9 ms/mmHg (19.9 ± 2.0 vs. 14.12 ± 1.6 ms/mmHg; p < 0.001) but did not change the phenylephrine pressor response (p = 0.878). Conclusion We applied an approach to assess individual baroreflex–chemoreflex interactions in human subjects. A subgroup exhibited significant impairments in baroreflex blood pressure buffering and BRS with peripheral chemoreflex activation. The methodology may have utility in elucidating individual pathophysiology and in targeting treatments modulating baroreflex or chemoreflex function.

AN EFFECT OF REDUCED BAROMETRIC PRESSURE ON THE PERIPHERAL CIRCULATION

1957 ◽  
Vol 35 (10) ◽  
pp. 777-783
Author(s):  
F. Girling ◽  
F. A. Sunahara
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Forearm Blood Flow ◽  
Human Subjects ◽  
Arterial Oxygen Saturation ◽  
Barometric Pressure ◽  
Peripheral Circulation ◽  
Arterial Oxygen ◽  
Blood Flows ◽  
The Past

Several groups of investigators have noted in the past that exposure to a reduced barometric pressure results in a decrease in peripheral blood flow.In the present study human subjects were exposed to a pressure of 225 mm. Hg with maintenace of arterial oxygen saturation, and forearm and hand blood flows were measured plethysmographically. Forearm blood flow was not affected by the exposure whereas hand blood flow was reduced in all subjects. Blood pressure and heart rate were also measured and showed no change during the experiment.

scholarly journals Comparison the Sedation Effect and Satisfaction of Two Combinations, Dexmedetomidine and Fentanyl with Midazolam and Fentanyl, in Patients Undergoing Bronchoscopy

2021 ◽  
Vol 6 (6) ◽  
Author(s):  
Alireza Kamali ◽  
Sepideh Sarkhosh ◽  
Hosein Kazemizadeh
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Saturation ◽  
Statistical Tests ◽  
Arterial Oxygen Saturation ◽  
Mean Blood Pressure ◽  
Arterial Oxygen ◽  
P Value ◽  
Double Blind ◽  
Significant Difference

Objectives: The aim of this study was to compare sedative effects of dexmedetomidine and fentanyl with midazolam and fentanyl in patients undergoing bronchoscopy. Methods: This study was a double-blind randomized clinical trial that was performed on 92 patients who referred to Amir al Momenin Hospital in Arak for bronchoscopy and underwent ASA 1 or 2 underlying grading procedure. Patients were randomly divided into two groups of dexmedetomidine and fentanyl (D) midazolam and fentanyl (M). Primary vital signs including hypertension and arterial oxygen saturation were monitored and recorded. Then all patients were injected with 2 μg / kg fentanyl as a painkiller and after 3 minutes 30 μg dexmedetomidine in syringe with code A and midazolam 3 mg in syringe with code B were injected to patients by an anesthesiologist. Then the two groups were compared in terms of pain at injection, conscious relaxation, satisfaction of operation, recovery time, hypotension and arterial oxygen saturation and drug side effects and data were analyzed by using statistical tests. Results: There was no significant difference between the two groups in terms of mean age and sex distribution. According to the results of this study, there was no significant difference between the two groups in mean blood pressure (P-value = 0.6) and mean heart rate (P-value = 0.4) at the time of bronchoscopy, but at 5 and 10 minutes after bronchoscopy there was a significant difference, mean blood pressure and heart rate were significantly lower in dexmedetomidine group. Conclusion: Both dexmedetomidine and midazolam drug groups contributed to the development of stable and sedative hemodynamics and satisfaction in patients undergoing bronchoscopy, however, the dexmedetomidine and fentanyl group showed a significant decrease in blood pressure and heart rate compared to midazolam and fentanyl and a weaker decrease in arterial oxygen saturation, and patients with bronchoscopy were more satisfied in the dexmedetomidine group.

Effects of a closed tracheal suction system on ventilatory and cardiovascular parameters

1992 ◽  
Vol 1 (3) ◽  
pp. 57-61 ◽  
Author(s):  
SA Harshbarger ◽  
LA Hoffman ◽  
TG Zullo ◽  
MR Pinsky
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Saturation ◽  
Respiratory Rate ◽  
Arterial Oxygen Saturation ◽  
Control Mode ◽  
Arterial Oxygen ◽  
Acid Base ◽  
Suction System ◽  
Repeated Measures Design

OBJECTIVE: To determine whether patients ventilated in the assist-control mode experienced a change in oxygenation, respiratory rate, inspiratory:expiratory ratio, heart rate, blood pressure or acid-base balance when suctioned with a closed tracheal suction system. DESIGN: A quasi-experimental, within-subject, repeated-measures design was used. SUBJECTS: 18 patients ventilated on a fraction of inspired oxygen of 0.47 +/- 0.17 and 2.3 +/- 5.0 cm H2O positive end-expiratory pressure. INTERVENTIONS: Two suction passes were performed, with measurements at baseline, immediately after the first suction pass, immediately before the second suction pass, immediately after the second suction pass, 2 minutes after the second suction pass and 5 minutes after the second suction pass. No hyperoxygenation was used. RESULTS: Significant differences were seen over time for arterial oxygen saturation, respiratory rate and inspiratory:expiratory ratio. Arterial oxygen saturation decreased to less than 90% in four subjects (range 88% to 89%), with a maximum fall of 9%. No significant differences were seen for heart rate, blood pressure, partial pressure of carbon dioxide, bicarbonate, time to nadir (lowest arterial oxygen saturation) or recovery time. CONCLUSIONS: Subjects ventilated in the assist-control mode and suctioned with a closed tracheal suction system did not experience significant changes in cardiovascular or acid-base parameters when suctioned without hyperoxygenation. Although most subjects did not become desaturated, four subjects experienced desaturation at one or more intervals. To prevent desaturation, hyperoxygenation should be used before and after suctioning with a closed tracheal suction system.

Blood pressure and heart rate during periodic breathing while asleep at high altitude

2000 ◽  
Vol 89 (3) ◽  
pp. 947-955 ◽  
Author(s):  
Giuseppe Insalaco ◽  
Salvatore Romano ◽  
Adriana Salvaggio ◽  
Alberto Braghiroli ◽  
Paola Lanfranchi ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
High Altitude ◽  
Arterial Oxygen Saturation ◽  
Cardiovascular Effects ◽  
Periodic Breathing ◽  
Normal Subjects ◽  
Arterial Oxygen ◽  
Cardiorespiratory Control ◽  
Arterial Blood

The ventilatory and arterial blood pressure (ABP) responses to isocapnic hypoxia during wakefulness progressively increased in normal subjects staying 4 wk at 5,050 m (Insalaco G, Romano S, Salvaggio A, Braghiroli A, Lanfranchi P, Patruno V, Donner CF, and Bonsignore G; J Appl Physiol 80: 1724–1730, 1996). In the same subjects ( n = 5, age 28–34 yr) and expedition, nocturnal polysomnography with ABP and heart rate (HR) recordings were obtained during the 1st and 4th week to study the cardiovascular effects of phasic (i.e., periodic breathing-dependent) vs. tonic (i.e., acclimatization-dependent) hypoxia during sleep. Both ABP and HR fluctuated during non-rapid eye movement sleep periodic breathing. None of the subjects exhibited an ABP increase during the ventilatory phases that correlated with the lowest arterial oxygen saturation of the preceding pauses. Despite attenuation of hypoxemia, ABP and HR behaviors during sleep in the 4th wk were similar to those in the 1st wk. Because ABP during periodic breathing in the ventilatory phase increased similarly to the ABP response to progressive hypoxia during wakefulness, ABP variations during ventilatory phases may reflect ABP responsiveness to peripheral chemoreflex sensitivity rather than the absolute value of hypoxemia, suggesting a major tonic effect of hypoxia on cardiorespiratory control at high altitude.

Diving response and arterial oxygen saturation during apnea and exercise in breath-hold divers

2002 ◽  
Vol 93 (3) ◽  
pp. 882-886 ◽  
Author(s):  
Johan P. A. Andersson ◽  
Mats H. Linér ◽  
Elisabeth Rünow ◽  
Erika K. A. Schagatay
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Saturation ◽  
Cold Water ◽  
Arterial Oxygen Saturation ◽  
Cycle Ergometer ◽  
Arterial Oxygen ◽  
Breath Hold ◽  
Diving Response ◽  
Face Immersion

This study addressed the effects of apnea in air and apnea with face immersion in cold water (10°C) on the diving response and arterial oxygen saturation during dynamic exercise. Eight trained breath-hold divers performed steady-state exercise on a cycle ergometer at 100 W. During exercise, each subject performed 30-s apneas in air and 30-s apneas with face immersion. The heart rate and arterial oxygen saturation decreased and blood pressure increased during the apneas. Compared with apneas in air, apneas with face immersion augmented the heart rate reduction from 21 to 33% ( P < 0.001) and the blood pressure increase from 34 to 42% ( P < 0.05). The reduction in arterial oxygen saturation from eupneic control was 6.8% during apneas in air and 5.2% during apneas with face immersion ( P < 0.05). The results indicate that augmentation of the diving response slows down the depletion of the lung oxygen store, possibly associated with a larger reduction in peripheral venous oxygen stores and increased anaerobiosis. This mechanism delays the fall in alveolar and arterial Po 2 and, thereby, the development of hypoxia in vital organs. Accordingly, we conclude that the human diving response has an oxygen-conserving effect during exercise.

scholarly journals Physiological Responses at Rest and Exercise to High Altitude in Lowland Children and Adolescents

Life ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1009
Author(s):  
Morin Lang ◽  
Guillem Vizcaíno-Muñoz ◽  
Paulina Jopia ◽  
Juan Silva-Urra ◽  
Ginés Viscor
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Saturation ◽  
Respiratory Rate ◽  
Children And Adolescents ◽  
Diastolic Blood Pressure ◽  
Arterial Oxygen Saturation ◽  
Submaximal Exercise ◽  
Arterial Oxygen ◽  
Children And Adolescent

During the last decades, the number of lowland children exposed to high altitude (HA) has increased drastically. Several factors may influence the development of illness after acute HA exposure on children and adolescent populations, such as altitude reached, ascent velocity, time spent at altitude and, especially, their age. The main goal of this study was to evaluate the resting cardiorespiratory physiological and submaximal exercise responses under natural HA conditions by means of the six-minute walking test (six MWT). Secondly, we aimed to identify the signs and symptoms associated with acute mountain sickness (AMS) onset after acute HA exposure in children and adolescents. Forty-two children and adolescents, 18 boys and 24 girls aged from 11 to 15 years old, participated in this study, which was performed at sea level (SL) and during the first 42 hours at HA (3330 m). The Lake Louise score (LLS) was recorded in order to evaluate the evolution of AMS symptoms. Submaximal exercise tests (six MWT) were performed at SL and HA. Physiological parameters such as heart rate, systolic and diastolic blood pressure, respiratory rate and arterialized oxygen saturation were measured at rest and after ending exercise testing at the two altitudes. After acute HA exposure, the participants showed lower arterial oxygen saturation levels at rest and after the submaximal test compared to SL (p < 0.001). Resting heart rate, respiratory rate and diastolic blood pressure presented higher values at HA (p < 0.01). Moreover, heart rate, diastolic blood pressure and dyspnea values increased before, during and after exercise at HA (p < 0.01). Moreover, submaximal exercise performance decreased at HA (p < 0.001). The AMS incidence at HA ranged from 9.5% to 19%, with mild to moderate symptoms. In conclusion, acute HA exposure in children and adolescent individuals produces an increase in basal cardiorespiratory parameters and a decrement in arterial oxygen saturation. Moreover, cardiorespiratory parameters increase during submaximal exercise at HA. Mild to moderate symptoms of AMS at 3330 m and adequate cardiovascular responses to submaximal exercise do not contraindicate the ascension of children and adolescents to that altitude, at least for a limited period of time.

Oxygen saturation and hemodynamic response in critically ill, mechanically ventilated adults during intrahospital transport

1995 ◽  
Vol 4 (2) ◽  
pp. 106-111 ◽  
Author(s):  
A Evans ◽  
EH Winslow
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Oxygen Saturation ◽  
Critically Ill ◽  
Arterial Oxygen Saturation ◽  
Heart Rhythm ◽  
Arterial Oxygen ◽  
Intrahospital Transport ◽  
Mechanically Ventilated

BACKGROUND: Despite the frequency of intrahospital transport of critically ill patients, little research has been done on this topic and the findings are contradictory. OBJECTIVES: To describe arterial oxygen saturation by pulse oximetry, heart rate, heart rhythm, and systolic blood pressure and equipment problems in critically ill, mechanically ventilated adults during intrahospital transport. METHODS: The sample consisted of 36 critically ill, mechanically ventilated adults who required transport out of the intensive care unit for diagnostic testing or procedures within the hospital. Arterial oxygen saturation, heart rate, heart rhythm, and systolic blood pressure were measured at baseline, at least every 5 minutes during transport to and from the test site and at the test site, and every 5 minutes for 15 minutes after return to the unit. Descriptive statistics were used to analyze the data. RESULTS: Nineteen patients (53%) had clinically important changes in arterial oxygen saturation, heart rate, and/or systolic blood pressure. New cardiac arrhythmias developed in two patients. The clinically important changes occurred most frequently at the test/procedure site. Equipment problems such as monitor power failure and ventilator disconnection occurred during transport of 4 patients (11%). Total time out of ICU averaged 62 +/- 30 (range = 26 to 166) minutes. CONCLUSIONS: Transport outside the intensive care unit places the critically ill patient at additional risk. Although transport is often unavoidable, its risks versus benefits should be carefully and collaboratively evaluated for every patient prior to making the decision for transport.

scholarly journals Evaluation of Vital Signs’ Fluctuations and Behavioral Responses in the Assessment of Pain in Patients With Traumatic Brain Injury

2020 ◽  
Author(s):  
atefeh ghanbari ◽  
Ezzat Paryad ◽  
Arefe safati ◽  
Ehsan Kazemnezhad Leyli ◽  
Elaheh Parsasalkisari
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Diastolic Blood Pressure ◽  
Arterial Oxygen Saturation ◽  
Vital Signs ◽  
Behavioral Responses ◽  
Arterial Oxygen ◽  
Significant Difference ◽  
Pain Detection

Abstract BackgroundTraumatic brain-injured (TBI) patients suffer severe pain. The assessment of behavioral responses and vital signs seems to be necessary for pain detection in these patients, a matter that this study aims to evaluate.MethodsThis cross sectional study uses repeated measures and included ninety-seven TBI patients from Poorsina hospital, Rasht, Iran. Patients’ relevant parameters were recorded using demographic checklist, specifications related to the disease, RASS, CPOT, and FPT tools. The data subsequently were entered into SPSS software V. 21 and were analyze using several tests including Bonferroni’s inferential test and Greenhouse-Geisser test, multiple analysis regression coefficient and general linear model by GEE method.ResultsThe average age of patients was 42.3 ± 18.2. The average consciousness level was 9.30 ± 2.96. There was significant difference between the painful and non-painful stimulations in heart rate, systolic blood pressure and diastolic blood pressure (p <0.001). Heart rate (p < 0.001, r = 0.253), number of respiration (p < 0.001, r = 0.173), systolic (p = 0.002, r = 0.128) and diastolic (p<0.001, r=0.223) blood pressures had a positive correlation with behavioral responses. However, the arterial oxygen saturation showed a negative correlation with behavioral responses (p < 0.001, r = -0.361). Statistical models demonstrated a significant direct relationship between CPOT with heart rate (β = 2.39, p < 0.001) and both systolic blood pressure (β= 1.31, p=0.002) and the fluctuations of diastolic blood pressure (β = 0.690, p = 0.009). ConclusionIt seems that behavioral responses are appropriate indices for pain detection. However, vital signs are not capable of being considered as proper indexes for pain assessment since they changed during several procedures while remained unchanged in other tests.

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