Diving Ability of the Platypus

1994 ◽  
Vol 42 (1) ◽  
pp. 17 ◽  
Author(s):  
BK Evans ◽  
DR Jones ◽  
J Baldwin ◽  
GRJ Gabbott
Keyword(s):  
Heart Rate ◽  
Consumption Rate ◽  
Anaerobic Metabolism ◽  
Haemoglobin Concentration ◽  
Total Blood ◽  
Physiological Capacity ◽  
Oxygen Stores ◽  
Recovery Times ◽  
Oxygen Carrying Capacity ◽  
Ldh Isozymes

Reports of the underwater endurance of the platypus differ. In the present study, most dives observed at Melbourne Zoo were less than 3 min, but several were longer (up to 11 min). Calculated dive: surface ratios were between 2.5:1 and 20:1. Most dives in the laboratory were between 30 s and 4 min duration, and heart rate fell in all dives, from pre-dive rates of 140-230 to 10-120 beats min-1. These falls in heart rate indicate that blood supply to many tissues is restricted, but the short recovery times after dives suggest there is little anaerobic metabolism. Similarly, the distribution and properties of LDH isozymes in skeletal muscle do not suggest heavy dependence on anaerobic glycolysis, and the ability of platypus muscles to 'buffer' metabolic acids that accumulate during anaerobiosis is low relative to other diving mammals. The platypus dives after a large inspiration (about 50 mL for a 1-kg animal). Total blood volume of the platypus is not known, but haematocrit, haemoglobin concentration and oxygen-carrying capacity have been shown to be high. Myoglobin oxygen stores in platypus are about 5 mL per kg body weight. Estimates of available oxygen stores and oxygen consumption rate indicate little need for anaerobic metabolism during normal dives, and it is suggested that the platypus has the physiological capacity for greater underwater endurance than previously suggested.

Breathing and bleeding – the problems of being big and running fast

2004 ◽  
Vol 32 ◽  
pp. 31-33
Author(s):  
D Marlin
Keyword(s):  
Gas Exchange ◽  
Relative Proportion ◽  
Haemoglobin Concentration ◽  
Muscle Cells ◽  
Capillary Density ◽  
Total Blood ◽  
Total Body Mass ◽  
Alveolar Oxygen ◽  
Oxygen Carrying Capacity ◽  
Exchange Surface

The ability to use oxygen during exercise is determined by a combination of the muscle mitochondrial density, the relative proportion of total body mass consisting of locomotory muscle, the gas exchange surface area and the capacity for conduction of oxygen from the gas exchange surface to the muscle cells, i.e. the heart and circulation. Other factors include: the ability to ventilate the lungs to ensure that a high gradient is maintained between the alveolar oxygen tension and that in the pulmonary capillaries to facilitate diffusion; the capillary density within muscle, the size of the muscle cells and the blood oxygen carrying capacity, which is primarily determined by the total blood volume and haemoglobin concentration.In absolute terms, the fastest animal on land is the Cheetah, which can reach speeds of up to 120 kmh. However, the Cheetah is a “sprinter” and can only achieve these speeds for distances of around 200 metres (<10 seconds).

Evaluating the Role of Anesthesia on Intraoperative Blood Loss and Visibility during Endoscopic Sinus Surgery: A Meta-analysis

2021 ◽  
pp. 194589242198915
Author(s):  
David C. Moffatt ◽  
Robert A. McQuitty ◽  
Alex E. Wright ◽  
Tawanda S. Kamucheka ◽  
Ali L. Haider ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Loss ◽  
Endoscopic Sinus Surgery ◽  
Average Rate ◽  
Meta Analysis ◽  
Sinus Surgery ◽  
Total Blood Loss ◽  
Total Blood ◽  
Intraoperative Bleeding ◽  
Significant Difference

Background Previous studies and meta analyses have led to incongruent and incomplete results respectively when total intravenous anesthesia (TIVA) and inhalational anesthesia (IA) are compared in endoscopic sinus surgeries in regards to intraoperative bleeding and visibility. Objective To perform a more comprehensive meta-analysis on randomized controlled trial (RCTs) comparing TIVA with IA in endoscopic sinus surgery to evaluate their effects on intraoperative bleeding and visibility. Methods A systematic review and meta-analysis of studies comparing TIVA and IA in endoscopic sinus surgery for chronic rhinosinusitis was completed in May 2020. Utilizing databases, articles were systematically screened for analysis and 19 studies met our inclusion criteria. The primary outcome included intraoperative visibility scores combining Boezaart, Wormald and Visual Analogue Scale (VAS). Secondary outcomes included rate of blood loss (mL/kg/min), estimated total blood loss (mL), Boezaart, Wormald scores, VAS, heart rate, and mean arterial pressure (MAP). Results 19 RCTs with 1,010 patients were analyzed. TIVA had a significantly lower intraoperative bleeding score indicating better endoscopic visibility (Boezaart, VAS, and Wormald) than IA (−0.514, p = 0.020). IA had a significantly higher average rate of blood loss than TIVA by 0.563 mL/kg/min (p = 0.016). Estimated total blood loss was significantly lower in TIVA than IA (−0.853 mL, p = 0.002). There were no significant differences between TIVA and IA in the mean heart rate (−0.225, p = 0.63) and MAP values (−0.126, p = 0.634). The subgroup analyses revealed no significant difference between TIVA and IA when remifentanil was not utilized and whenever desflurane was the IA agent. Conclusion TIVA seemed to have superior intraoperative visibility scores and blood loss during endoscopic sinus surgery when compared to IA. However, the results are not consistent when stratifying the results based on the use of remifentanil and different inhaled anesthetics. Therefore, the conclusion cannot be made that one approach is superior to the other.

Cerebral oxygen availability by NIR spectroscopy during transient hypoxia in humans

1990 ◽  
Vol 69 (3) ◽  
pp. 907-913 ◽  
Author(s):  
N. B. Hampson ◽  
E. M. Camporesi ◽  
B. W. Stolp ◽  
R. E. Moon ◽  
J. E. Shook ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Volume ◽  
Near Infrared ◽  
Cerebral Blood Volume ◽  
Minute Ventilation ◽  
Nir Spectroscopy ◽  
Redox Status ◽  
Total Blood ◽  
Arterial Ph

The effects of mild hypoxia on brain oxyhemoglobin, cytochrome a,a3 redox status, and cerebral blood volume were studied using near-infrared spectroscopy in eight healthy volunteers. Incremental hypoxia reaching 70% arterial O2 saturation was produced in normocapnia [end-tidal PCO2 (PETCO2) 36.9 +/- 2.6 to 34.9 +/- 3.4 Torr] or hypocapnia (PETCO2 32.8 +/- 0.6 to 23.7 +/- 0.6 Torr) by an 8-min rebreathing technique and regulation of inspired CO2. Normocapnic hypoxia was characterized by progressive reductions in arterial PO2 (PaO2, 89.1 +/- 3.5 to 34.1 +/- 0.1 Torr) with stable PETCO2, arterial PCO2 (PaCO2), and arterial pH and resulted in increases in heart rate (35%) systolic blood pressure (14%), and minute ventilation (5-fold). Hypocapnic hypoxia resulted in progressively decreasing PaO2 (100.2 +/- 3.6 to 28.9 +/- 0.1 Torr), with progressive reduction in PaCO2 (39.0 +/- 1.6 to 27.3 +/- 1.9 Torr), and an increase in arterial pH (7.41 +/- 0.02 to 7.53 +/- 0.03), heart rate (61%), and ventilation (3-fold). In the brain, hypoxia resulted in a steady decline of cerebral oxyhemoglobin content and a decrease in oxidized cytochrome a,a3. Significantly greater loss of oxidized cytochrome a,a3 occurred for a given decrease in oxyhemoglobin during hypocapnic hypoxia relative to normocapnic hypoxia. Total blood volume response during hypoxia also was significantly attenuated by hypocapnia, because the increase in volume was only half that of normocapnic subjects. We conclude that cytochrome a,a3 oxidation level in vivo decreases at mild levels of hypoxia. PaCO is an important determinant of brain oxygenation, because it modulates ventilatory, cardiovascular, and cerebral O2 delivery responses to hypoxia.

Implication of CO inactivation on myoglobin function

2006 ◽  
Vol 290 (6) ◽  
pp. C1616-C1624 ◽  
Author(s):  
Youngran Chung ◽  
Shih-Jwo Huang ◽  
Alan Glabe ◽  
Thomas Jue
Keyword(s):  
Heart Rate ◽  
Electrical Stimulation ◽  
Physiological Response ◽  
Consumption Rate ◽  
Contractile Function ◽  
High Energy ◽  
Facilitated Diffusion ◽  
High Energy Phosphate ◽  
H Nmr

Myoglobin (Mb) has a purported role in facilitating O2 diffusion in tissue, especially as cellular Po2 drops or the respiration demand increases. Inhibiting Mb with CO under conditions that accentuate the facilitated diffusion role should then elicit a significant physiological response. In one set of experiments, the perfused myocardium received buffer with decreasing Po2 (225, 129, and 64 mmHg). Intracellular Po2 declined, as reflected in the 1H NMR Val E11 signal of MbO2 (67%, 32%, and 18%). The addition of 6% CO further reduced the available MbO2 (11%, 9%, and 7%), as evidenced by the decline of the MbO2 Val E11 signal intensity at −2.76 ppm. In a second set of experiments, electrical stimulation increased the heart rate (300, 450, and 540 beats/min) and correspondingly the O2 consumption rate (MV̇o2). Intracellular Po2 also declined, as reflected in the slight drop in the MbO2 signal (100%, 96%, and 82%). MV̇o2 increased (100%, 114%, 165%). The addition of 3% CO in the stimulated hearts further decreased the available MbO2 (46%, 44%, and 29%). In all cases, CO inactivation of Mb does not induce any change in the respiration rate, contractile function, and high-energy phosphate levels. Moreover, the MbCO/MbO2 partition coefficient shifts dramatically from its in vitro value during hypoxia and increased work. The observation suggests a modulation of an intracellular O2 gradient. Overall, the experimental observations provide no evidence of a facilitated diffusion role for Mb in perfused myocardium and implicate a physiologically responsive intracellular O2 gradient.

scholarly journals Oxygen and Carbon Dioxide Transport Characteristics of the Blood of the Nile Monitor Lizard (Varanus Niloticus)

1987 ◽  
Vol 130 (1) ◽  
pp. 27-38
Author(s):  
JAMES W. HICKS ◽  
ATSUSHI ISHIMATSU ◽  
NORBERT HEISLER
Keyword(s):  
Carbon Dioxide ◽  
Haemoglobin Concentration ◽  
Oxygen Affinity ◽  
Total Blood ◽  
Carbon Dioxide Transport ◽  
Monitor Lizard ◽  
The Right ◽  
Dissociation Curves

Oxygen and carbon dioxide dissociation curves were constructed for the blood of the Nile monitor lizard, Varanus niloticus, acclimated for 12h at 25 and 35°C. The oxygen affinity of Varanus blood was low when Pco2 w a s in the range of in vivo values (25°C: P50 = 34.3 at PCOCO2 = 21 mmHg; 35°C: P50 = 46.2 mmHg at PCOCO2 = 35 mmHg; 1 mmHg = 133.3 Pa), and the oxygen dissociation curves were highly sigmoidal (Hill's n = 2.97 at 25°C and 3.40 at 35°C). The position of the O2 curves was relatively insensitive to temperature change with an apparent enthalpy of oxygenation (ΔH) of −9.2kJ mol−1. The carbon dioxide dissociation curves were shifted to the right with increasing temperature by decreasing total CCOCO2 at fixed PCOCO2, whereas the state of oxygenation had little effect on total blood CO2 content. The in vitro buffer value of true plasma (Δ[HCO3−]pl/-ΔpHpl) rose from 12.0 mequiv pH−1−1 at 25°C to 17.5 mequiv pH−11−1 at 35°C, reflecting a reversible increase of about 30% in haemoglobin concentration and haematocrit levels during resting conditions in vivo.

Blood oxygen transport and metabolism of the confined lugworm Arenicola marina (L.)

1975 ◽  
Vol 63 (3) ◽  
pp. 647-660
Author(s):  
A. Toulmond
Keyword(s):  
Anaerobic Metabolism ◽  
Sea Water ◽  
Blood Oxygen ◽  
Total Blood ◽  
Oxygen Saturation Level ◽  
Gas Exchanges ◽  
Water Oxygen ◽  
Buffer Power ◽  
Flow Through ◽  
Total Blood Flow

Oxygen consumption (MO2), haemoglobin oxygen saturation level (SVO2) and pH (pHv) in prebranchial blood were measured in lugworms experimentally confined in sea water at 15 degrees C. Total blood flow through the gills (Vb) was estimated. For sea water oxygen partial pressure (PwO2) between 120 and 150 Torr MO2, SVO2 and Vb were high and nearly constant. For PwO2 less than 120 Torr, Vb fell quickly, MO2 progressively dropped, and metabolism remained aerobic at the expense of the prebrancial blood oxygen store. For PwO2 less than 50 Torr, Vb and SvO2 values were extremely low, and the low pHv and the modified buffer power of the surrounding sea water showed that anaerobic metabolism was occurring. Changes in respiratory gas exchanges and metabolism during the tidal cycle are deduced from the comparison of these results with data obtained in the field.

scholarly journals Effects of prophylactic antibiotic-treatment on post-surgical recovery following intraperitoneal bio-logger implantation in rainbow trout

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Per Hjelmstedt ◽  
Henrik Sundh ◽  
Jeroen Brijs ◽  
Andreas Ekström ◽  
Kristina Snuttan Sundell ◽  
...  
Keyword(s):  
Heart Rate ◽  
Rainbow Trout ◽  
Prophylactic Treatment ◽  
Prophylactic Antibiotic ◽  
Post Surgery ◽  
Recovery Times ◽  
Prolonged Recovery ◽  
Surgical Recovery ◽  
Prophylactic Antibiotic Treatment ◽  
Freely Moving

AbstractBio-logging devices can provide unique insights on the life of freely moving animals. However, implanting these devices often requires invasive surgery that causes stress and physiological side-effects. While certain medications in connection to surgeries have therapeutic capacity, others may have aversive effects. Here, we hypothesized that the commonly prescribed prophylactic treatment with enrofloxacin would increase the physiological recovery rate and reduce the presence of systemic inflammation following the intraperitoneal implantation of a heart rate bio-logger in rainbow trout (Oncorhynchus mykiss). To assess post-surgical recovery, heart rate was recorded for 21 days in trout with or without enrofloxacin treatment. Contrary to our hypothesis, treated trout exhibited a prolonged recovery time and elevated resting heart rates during the first week of post-surgical recovery compared to untreated trout. In addition, an upregulated mRNA expression of TNFα in treated trout indicate a possible inflammatory response 21 days post-surgery. Interestingly, the experience level of the surgeon was observed to have a long-lasting impact on heart rate. In conclusion, our study showed no favorable effects of enrofloxacin treatment. Our findings highlight the importance of adequate post-surgical recovery times and surgical training with regards to improving the welfare of experimental animals and reliability of research outcomes.

Energy Expenditure of Sockeye Salmon, Oncorhynchus nerka, During Sustained Performance

1973 ◽  
Vol 30 (12) ◽  
pp. 1799-1809 ◽  
Author(s):  
J. R. Brett
Keyword(s):  
Body Composition ◽  
Sockeye Salmon ◽  
Consumption Rate ◽  
Anaerobic Metabolism ◽  
Oncorhynchus Nerka ◽  
Total Oxygen ◽  
Metabolic Equivalent ◽  
Body Tissues ◽  
Sustained Performance ◽  
The Difference

Fingerling and adult sockeye salmon (Oncorhynchus nerka) were subjected to long periods of sustained swimming (10–20 days) in air-saturated fresh water. Energy expended was computed from change in body composition and compared with the metabolic equivalent from multiple determinations of oxygen-consumption rate. Caloric loss from body substance exceeded that estimated from total oxygen uptake by an average of 19.8%. The reasons for the difference, and the assumptions involved, are discussed. The difference apparently arises from slight excretion of partially metabolized fuels (anaerobic metabolism) and loss from sloughed body tissues. An oxycalorific equivalent of 4.8 kcal/liter O2 is considered an acceptable value for fish.

scholarly journals Xenon Anesthesia Improves Respiratory Gas Exchanges in Morbidly Obese Patients

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Antonio Abramo ◽  
Claudio Di Salvo ◽  
Francesca Foltran ◽  
Francesco Forfori ◽  
Marco Anselmino ◽  
...  
Keyword(s):  
Heart Rate ◽  
Diastolic Pressure ◽  
Plateau Pressure ◽  
Morbidly Obese ◽  
Obese Patients ◽  
Gas Exchanges ◽  
Pressure Oxygen ◽  
Extubation Time ◽  
Recovery Times ◽  
Induction Of Anaesthesia

Background. Xenon-in-oxygen is a high density gas mixture and may improve PaO2/FiO2 ratio in morbidly obese patients uniforming distribution of ventilation during anesthesia.Methods. We compared xenon versus sevoflurane anesthesia in twenty adult morbidly obese patients (BMI>35) candidate for roux-en-Y laparoscopic gastric bypass and assessed PaO2/FiO2 ratio at baseline, at 15 min from induction of anaesthesia and every 60 min during surgery. Differences in intraoperative and postoperative data including heart rate, systolic and diastolic pressure, oxygen saturation, plateau pressure, eyes opening and extubation time, Aldrete score on arrival to the PACU were compared by the Mann-Whitney test and were considered as secondary aims. Moreover the occurrence of side effects and postoperative analgesic demand were assessed.Results. In xenon group PaO2-FiO2 ratio was significantly higher after 60 min and 120 min from induction of anesthesia; heart rate and overall remifentanil consumption were lower; the eyes opening time and the extubation time were shorter; morphine consumption at 72 hours was lower; postoperative nausea was more common.Conclusions. Xenon anesthesia improved PaO2/FiO2 ratio and maintained its distinctive rapid recovery times and cardiovascular stability. A reduction of opioid consumption during and after surgery and an increased incidence of PONV were also observed in xenon group.

Effects of Venesection on Leg Blood Flow in Claudicants with High-Normal Haematocrit

1988 ◽  
Vol 33 (4) ◽  
pp. 298-299 ◽  
Author(s):  
A.R. Turner ◽  
G.D.O. Lowe ◽  
C.D. Forbes ◽  
J. G. Pollock
Keyword(s):  
Blood Flow ◽  
Intermittent Claudication ◽  
Carrying Capacity ◽  
Blood Viscosity ◽  
Oxygen Delivery ◽  
Peak Flow ◽  
Haemoglobin Concentration ◽  
Leg Blood Flow ◽  
Calf Blood Flow ◽  
Oxygen Carrying Capacity

Patients with intermittent claudication frequently have high-normal levels of haematocrit and hence blood viscosity, which may contribute to decreased calf blood flow on exercise, and hence to the symptom of claudication. Reduction in haematocrit and viscosity by serial venesection in eight patients with stable claudication and high-normal haematocrit (mean 0.50) was performed, and the effects on claudication, calf blood flow, and calf oxygen delivery were studied. Following reduction in haematocrit to low-normal levels (mean 0.44), resting calf blood flow was unchanged; peak flow after ischaemic exercise increased slightly (+17%), but peak oxygen delivery (peak flow × haemoglobin concentration) was unchanged. Hence any increase in calf blood flow in the symptomatic leg is balanced by a decrease in oxygen-carrying capacity after venesection. No increase in claudication time would therefore be expected, and none was observed in the present study.

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