Heart rates of muskrats diving under simulated field conditions: persistence of the bradycardia response and factors modifying its expression

1989 ◽  
Vol 67 (7) ◽  
pp. 1783-1792 ◽  
Author(s):  
Robert A. MacArthur ◽  
Cindy M. Karpan
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Motor Activity ◽  
Water Temperature ◽  
Field Conditions ◽  
Diving Response ◽  
Heart Rates ◽  
Feeding Station ◽  
Wide Range ◽  
Simulated Field

A marked, rapidly deployed bradycardia accompanied every voluntary dive by muskrats diving under a wide range of simulated field conditions in the laboratory. Telemetered heart rates were typically stable during submergence, with little evidence of postdive tachycardia or anticipatory changes in cardiac frequency prior to onset or termination of spontaneous dives. The extent of bradycardia varied with the type of dive; heart rate was highest during foraging trips and lowest during escape dives provoked by the investigators. Diving heart rate was positively correlated with the predive rate in escape dives but not foraging or exploratory dives. In animals trained to swim an underwater maze separating a simulated lodge from a feeding station, the extent of bradycardia increased with the period of submergence. This relationship was strongest for escape dives and was attributed mainly to a reduction in motor activity with time submerged. Several escape dives more than 3 min in duration were documented in both field and laboratory and all were characterized by prolonged periods of inactivity underwater. Heart rate during exploratory and foraging dives varied positively with both water (4–30 °C) and telemetered abdominal (30–38.4 °C) temperature. Type of dive, body temperature, and water temperature accounted for 31% of the variance in heart rate of diving muskrats. These results suggest that while the classic diving response is largely preserved in freely diving muskrats, the extent of bradycardia varies with the nature of the dive and is subject to cortical and thermal influences.

scholarly journals Distribution of Pediatric Vital Signs in the Emergency Department: A Nationwide Study

Children ◽  
2020 ◽  
Vol 7 (8) ◽  
pp. 89
Author(s):  
Woori Bae ◽  
Kyunghoon Kim ◽  
Bongjin Lee
Keyword(s):  
Emergency Department ◽  
Heart Rate ◽  
Body Temperature ◽  
Respiratory Rate ◽  
Life Support ◽  
Vital Signs ◽  
Reference Ranges ◽  
Normal Body Temperature ◽  
Heart Rates ◽  
Normal Body

To effectively use vital signs as indicators in children, the magnitude of deviation from expected vital sign distribution should be determined. The purpose of this study is to derive age-specific centile charts for the heart rate and respiratory rate of the children who visited the emergency department. This study used the Korea’s National Emergency Department Information System dataset. Patients aged <16 years visiting the emergency department between 1 January 2016 and 31 December 2017 were included. Heart rate and respiratory rate centile charts were derived from the population with normal body temperature (36 to <38 °C). Of 1,901,816 data points retrieved from the database, 1,454,372 sets of heart rates and 1,458,791 sets of respiratory rates were used to derive centile charts. Age-specific centile charts and curves of heart rates and respiratory rates showed a decline in heart rate and respiratory rate from birth to early adolescence. There were substantial discrepancies in the reference ranges of Advanced Paediatric Life Support and Pediatric Advanced Life Support guidelines. Age-based heart rate and respiratory rate centile charts at normal body temperature, derived from children visiting emergency departments, serve as new evidence-based data and can be used in follow-up studies to improve clinical care for children.

Beat-by-beat modulation of AV conduction. I. Heart rate and respiratory influences

1986 ◽  
Vol 251 (6) ◽  
pp. H1126-H1133 ◽  
Author(s):  
M. R. Warner ◽  
J. M. Loeb
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oscillatory Activity ◽  
Conduction Time ◽  
Atrial Pacing ◽  
Sinus Arrhythmia ◽  
Heart Rates ◽  
Av Conduction ◽  
Wide Range ◽  
Cyclic Changes

We examined the integration of heart rate and neural influences at the atrioventricular (AV) node in conscious dogs. Animals were anesthetized and, under sterile conditions, instrumented to chronically record atrial and ventricular electrograms and blood pressure. In the conscious state, electrocardiogram (ECG), respiration, blood pressure, and electrograms were recorded on a beat-by-beat basis, and heart rate and AV interval were plotted graphically as a function of time. Resting animals exhibited both respiratory sinus arrhythmia and marked oscillations in AV conduction time associated with respiration. During inspiration AV interval was shortened, and during expiration AV interval was prolonged. To obviate the effect of cyclic changes in heart rate, atrial pacing was used to increase heart rate over a wide range both abruptly and linearly. Regardless of the pattern of heart rate change, AV interval oscillated at the respiratory frequency at pacing rates 10-100 beats/min above control. Higher levels of atrial pacing resulted in AV conduction patterns that were correlated with changes in blood pressure. Thus in the conscious dog variations in AV conduction time occur on a beat-by-beat basis in conjunction with respiration; oscillatory activity of AV conduction is not dependent on simultaneous changes in heart rate; and during atrial pacing, autonomic neural activity associated with respiration and blood pressure appears to dynamically modulate AV conduction with respiratory effects predominating at low heart rates and blood pressure effects at high heart rates.

scholarly journals Heart rate reveals torpor at high body temperatures in lowland tropical free-tailed bats

2017 ◽  
Vol 4 (12) ◽  
pp. 171359 ◽  
Author(s):  
M. Teague O'Mara ◽  
Sebastian Rikker ◽  
Martin Wikelski ◽  
Andries Ter Maat ◽  
Henry S. Pollock ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Ambient Temperature ◽  
The Body ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Wide Range ◽  
Save Energy ◽  
Molossus Molossus

Reduction in metabolic rate and body temperature is a common strategy for small endotherms to save energy. The daily reduction in metabolic rate and heterothermy, or torpor, is particularly pronounced in regions with a large variation in daily ambient temperature. This applies most strongly in temperate bat species (order Chiroptera), but it is less clear how tropical bats save energy if ambient temperatures remain high. However, many subtropical and tropical species use some daily heterothermy on cool days. We recorded the heart rate and the body temperature of free-ranging Pallas' mastiff bats ( Molossus molossus ) in Gamboa, Panamá, and showed that these individuals have low field metabolic rates across a wide range of body temperatures that conform to high ambient temperature. Importantly, low metabolic rates in controlled respirometry trials were best predicted by heart rate, and not body temperature . Molossus molossus enter torpor-like states characterized by low metabolic rate and heart rates at body temperatures of 32°C, and thermoconform across a range of temperatures. Flexible metabolic strategies may be far more common in tropical endotherms than currently known.

Heat exchanges in wet suits

1985 ◽  
Vol 58 (3) ◽  
pp. 770-777 ◽  
Author(s):  
A. H. Wolff ◽  
S. R. Coleshaw ◽  
C. G. Newstead ◽  
W. R. Keatinge
Keyword(s):  
Body Temperature ◽  
Water Temperature ◽  
Cold Water ◽  
Whole Body ◽  
Metabolic Responses ◽  
Body Temperatures ◽  
Postural Changes ◽  
Wide Range ◽  
Heat Exchanges ◽  
Skin Temperatures

Flow of water under foam neoprene wet suits could halve insulation that the suits provided, even at rest in cold water. On the trunk conductance of this flow was approximately 6.6 at rest and 11.4 W . m-2 . C-1 exercising; on the limbs, it was only 3.4 at rest and 5.8 W . m-2 . degrees C-1 exercising; but during vasoconstriction in the cold, skin temperatures on distal parts of limbs were lower than were those of the trunk, allowing adequate metabolic responses. In warm water, minor postural changes and movement made flow under suits much higher, approximately 60 on trunk and 30 W . m-2 . degrees C-1 on limbs, both at rest and at work. These changes in flow allowed for a wide range of water temperatures at which people could stabilize body temperature in any given suit, neither overheating when exercising nor cooling below 35 degrees C when still. Even thin people with 4- or 7- mm suits covering the whole body could stabilize their body temperatures in water near 10 degrees C in spite of cold vasodilatation. Equations to predict limits of water temperature for stability with various suits and fat thicknesses are given.

Individual-Specific QT Interval Correction for Drugs With Substantial Heart Rate Effect Using Holter ECGs Extracted Over a Wide Range of Heart Rates

2018 ◽  
Vol 58 (8) ◽  
pp. 1013-1019 ◽  
Author(s):  
Gopi Krishna Panicker ◽  
Pramod Kadam ◽  
Saikat Chakraborty ◽  
Snehal Kothari ◽  
J. Rick Turner ◽  
...  
Keyword(s):  
Heart Rate ◽  
Qt Interval ◽  
Rate Effect ◽  
Heart Rates ◽  
Wide Range ◽  
Heart Rate Effect

Physiological Responses of Medical Team Members to a Simulated Emergency in Tropical Field Conditions

2013 ◽  
Vol 28 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Matt B. Brearley ◽  
Michael F. Heaney ◽  
Ian N. Norton
Keyword(s):  
Body Temperature ◽  
Environmental Conditions ◽  
Core Body Temperature ◽  
Physiological Responses ◽  
Field Conditions ◽  
Medical Team ◽  
Team Members ◽  
Medical Response ◽  
Simulated Field ◽  
Core Body

AbstractIntroductionResponses to physical activity while wearing personal protective equipment in hot laboratory conditions are well documented. However less is known of medical professionals responding to an emergency in hot field conditions in standard attire. Therefore, the purpose of this study was to assess the physiological responses of medical responders to a simulated field emergency in tropical conditions.MethodsTen subjects, all of whom were chronically heat-acclimatized health care workers, volunteered to participate in this investigation. Participants were the medical response team of a simulated field emergency conducted at the Northern Territory Emergency Services training grounds, Yarrawonga, NT, Australia. The exercise consisted of setting up a field hospital, transporting patients by stretcher to the hospital, triaging and treating the patients while dressed in standard medical response uniforms in field conditions (mean ambient temperature of 29.3°C and relative humidity of 50.3%, apparent temperature of 27.9°C) for a duration of 150 minutes. Gastrointestinal temperature was transmitted from an ingestible sensor and used as the index of core temperature. An integrated physiological monitoring device worn by each participant measured and logged heart rate, chest temperature and gastrointestinal temperature throughout the exercise. Hydration status was assessed by monitoring the change between pre- and post-exercise body mass and urine specific gravity (USG).ResultsMean core body temperature rose from 37.5°C at the commencement of the exercise to peak at 37.8°C after 75 minutes. The individual peak core body temperature was 38.5°C, with three subjects exceeding 38.0°C. Subjects sweated 0.54 L per hour and consumed 0.36 L of fluid per hour, resulting in overall dehydration of 0.7% of body mass at the cessation of exercise. Physiological strain index was indicative of little to low strain.ConclusionsThe combination of the unseasonably mild environmental conditions and moderate work rates resulted in minimal heat storage during the simulated exercise. As a result, low sweat rates manifested in minimal dehydration. When provided with access to fluids in mild environmental conditions, chronically heat-acclimatized medical responders can meet their hydration requirements through ad libitum fluid consumption. Whether such an observation is replicated under a harsher thermal load remains to be investigated.BrearleyMB, HeaneyMF, NortonIN. Physiological responses of medical team members to a simulated emergency in tropical field conditions. Prehosp Disaster Med. 2013;28(2):1-6.

Pulse rate-rectal temperature relationships during prolonged work

1978 ◽  
Vol 44 (3) ◽  
pp. 450-454 ◽  
Author(s):  
K. V. Kuhlemeier ◽  
J. M. Miller
Keyword(s):  
Heart Rate ◽  
Rectal Temperature ◽  
Industrial Workers ◽  
Heart Rates ◽  
Reasonable Degree ◽  
Wide Range ◽  
Degree Of Confidence ◽  
Regression Techniques ◽  
The Relationship ◽  
Environmental Temperatures

Forty-six industrial workers performed a total of 653 1-h work bouts over a wide range of work rates )142–273 W/m2) and environmental temperatures (11–35 degrees C corrected effective temperature) in the summer and winter seasons. Simultaneous measurements of heart rates and rectal temperatures were made at the end of each work period, and the relationship between heart rate and rectal temperature was computed with standard multiple linear regression techniques. The overall regression equation is: heart rate (beats/min) = 29.3 (beats/min. degrees C) x rectal temperature (degrees C) - 988.6 (beats/min). The relationship is significantly altered by work rate and job- and season-acquired acclimatization of the subjects. These data suggest that the average heart rates of industrial workers during prolonged work can be predicted from rectal temperatures with a reasonable degree of confidence if the degree of acclimatization and work rates are known. For a rectal temperature of 38.0 degrees C the expected heart rate during prolonged work ranges from 109 beats/min in acclimatized men working at low rates to 143 for unacclimatized men working at heavy rates.

scholarly journals Intelligent Medical System with Low-Cost Wearable Monitoring Devices to Measure Basic Vital Signals of Admitted Patients

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 918
Author(s):  
Siraporn Sakphrom ◽  
Thunyawat Limpiti ◽  
Krit Funsian ◽  
Srawouth Chandhaket ◽  
Rina Haiges ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Time Delay ◽  
Body Temperature ◽  
Low Cost ◽  
Vital Signs ◽  
Smart Devices ◽  
Wide Range ◽  
And Function ◽  
Short Time

This article presents the design of a low-cost Wireless Body Sensor Network (WBSN) for monitoring vital signs including a low-cost smart wristwatch that contains an ESP-32 microcontroller and three sensors: heart rate (HR), blood pressure (BP) and body temperature (BT), and an Internet of Things (IoT) platform. The vital signs data are processed and displayed on an OLED screen of the patient’s wristwatch and sent the data over a wireless connection (Wi-Fi) and a Cloud Thing Board system, to store and manage the data in a data center. The data can be analyzed and notified to medical staff when abnormal signals are received from the sensors based on a set parameters from specialists. The proposed low-cost system can be used in a wide range of applications including field hospitals for asymptotic or mild-condition COVID-19 patients as the system can be used to screen those patients out of symptomatic patients who require more costly facilities in a hospital with considerably low expense and installation time, also suitable for bedridden patients, palliative care patients, etc. Testing experiments of a 60-person sample size showed an acceptable accuracy level compared with standard devices when testing with 60 patient-samples with the mean errors heart rate of 1.22%, systolic blood pressure of 1.39%, diastolic blood pressure of 1.01%, and body temperature of 0.13%. According to testing results with 10 smart devices connected with the platform, the time delay caused by the distance between smart devices and the router is 10 s each round with the longest outdoor distance of 200 m. As there is a short-time delay, it does not affect the working ability of the smart system. It is still making the proposed system be able to show patient’s status and function in emergency cases.

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