Metabolic actions of morphine in conscious chronically instrumented pigs

1991 ◽  
Vol 260 (6) ◽  
pp. R1051-R1057
Author(s):  
C. A. Bossone ◽  
J. P. Hannon
Keyword(s):  
Energy Metabolism ◽  
Plasma Concentrations ◽  
Potassium Phosphate ◽  
Heat Content ◽  
Co2 Production ◽  
Morphine Injection ◽  
Thermal Status ◽  
Intravenous Morphine ◽  
Total Body ◽  
Body Heat

Effects of a modest dose of morphine sulfate (1 mg/kg) on total body energy metabolism, body thermal status, and the plasma concentrations of certain electrolytes and metabolites were investigated in conscious chronically instrumented pigs (n = 8). Control pigs (n = 8) received an equivalent volume of normal saline. Intravenous morphine injection led to an excitatory state associated with significant (P less than or equal to 0.05) immediate increases in O2 consumption. CO2 production, respiratory exchange ratio, and plasma concentrations of lactate, glucose, potassium, phosphate, epinephrine, and norepinephrine. Significant more gradual increases were observed in rectal and skin temperatures, body heat content, and the plasma concentrations of adrenocorticotropic hormone, cortisol, and phosphate. The hypermetabolic state persisted for approximately 1 h. Thereafter, most functional variables regressed toward, but did not reach, control levels. Increased muscle activity appeared to be the major factor underlying the rise in energy metabolism. Body heat storage after morphine injection appeared to be attributable to increased heat production coupled with an inadequate rise in heat loss.

Tissue Heat Content and Distribution during and after Cardiopulmonary Bypass at 31 [degree sign]C and 27 [degree sign]C 

1998 ◽  
Vol 88 (6) ◽  
pp. 1511-1518 ◽  
Author(s):  
Angela Rajek ◽  
Rainer Lenhardt ◽  
Daniel I. Sessler ◽  
Andrea Kurz ◽  
Gunther Laufer ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Temperature Gradient ◽  
Heat Content ◽  
Peripheral Tissue ◽  
Tissue Temperature ◽  
Peripheral Compartment ◽  
Peripheral Tissues ◽  
The Core ◽  
Total Body ◽  
Body Heat

Background Afterdrop following cardiopulmonary bypass results from redistribution of body heat to inadequately warmed peripheral tissues. However, the distribution of heat between the thermal compartments and the extent to which core-to-peripheral redistribution contributes to post-bypass hypothermia remains unknown. Methods Patients were cooled during cardiopulmonary bypass to nasopharyngeal temperatures near 31 degrees C (n=8) or 27 degrees C (n=8) and subsequently rewarmed by the bypass heat exchanger to approximately 37.5 degrees C. A nasopharyngeal probe evaluated core (trunk and head) temperature and heat content. Peripheral compartment (arm and leg) temperature and heat content were estimated using fourth-order regressions and integration over volume from 19 intramuscular needle thermocouples, 10 skin temperatures, and "deep" foot temperature. Results In the 31 degrees C group, the average peripheral tissue temperature decreased to 31.9+/-1.4 degrees C (means+/-SD) and subsequently increased to 34+/-1.4 degrees C at the end of bypass. The core-to-peripheral tissue temperature gradient was 3.5+/-1.8 degrees C at the end of rewarming, and the afterdrop was 1.5+/-0.4 degrees C. Total body heat content decreased 231+/-93 kcal. During pump rewarming, the peripheral heat content increased to 7+/-27 kcal below precooling values, whereas the core heat content increased to 94+/-33 kcal above precooling values. Body heat content at the end of rewarming was thus 87+/-42 kcal more than at the onset of cooling. In the 27 degrees C group, the average peripheral tissue temperature decreased to a minimum of 29.8 +/-1.7 degrees C and subsequently increased to 32.8+/-2.1 degrees C at the end of bypass. The core-to-peripheral tissue temperature gradient was 4.6+/-1.9 degrees C at the end of rewarming, and the afterdrop was 2.3+/-0.9 degrees C. Total body heat content decreased 419+/-49 kcal. During pump rewarming, core heat content increased to 66+/-23 kcal above precooling values, whereas peripheral heat content remained 70+/-42 kcal below precooling values. Body heat content at the end of rewarming was thus 4+/-52 kcal less than at the onset of cooling. Conclusions Peripheral tissues failed to fully rewarm by the end of bypass in the patients in the 27 degrees C group, and the afterdrop was 2.3+/-0.9 degrees C. Peripheral tissues rewarmed better in the patients in the 31 degrees C group, and the afterdrop was only 1.5+/-0.4 degrees C.

Effects of acetazolamide on metabolic and respiratory responses to exercise at maximal O2 uptake

1990 ◽  
Vol 68 (2) ◽  
pp. 617-626 ◽  
Author(s):  
R. J. Rose ◽  
D. R. Hodgson ◽  
T. B. Kelso ◽  
L. J. McCutcheon ◽  
W. M. Bayly ◽  
...  
Keyword(s):  
Muscle Metabolism ◽  
Blood Gases ◽  
Co2 Production ◽  
O2 Uptake ◽  
Blood Temperature ◽  
Arterial Ph ◽  
Muscle Ph ◽  
Venous Pco2 ◽  
Total Body ◽  
Exercise Muscle

Changes in blood gases, ions, lactate, pH, hemoglobin, blood temperature, total body metabolism, and muscle metabolites were measured before and during exercise (except muscle), at fatigue, and during recovery in normal and acetazolamide-treated horses to test the hypothesis that an acetazolamide-induced acidosis would compromise the metabolism of the horse exercising at maximal O2 uptake. Acetazolamide-treated horses had a 13-mmol/l base deficit at rest, higher arterial Po2 at rest and during exercise, higher arterial and mixed venous Pco2 during exercise, and a 48-s reduction in run time. Arterial pH was lower during exercise but not in recovery after acetazolamide. Blood temperature responses were unaffected by acetazolamide administration. O2 uptake was similar during exercise and recovery after acetazolamide treatment, whereas CO2 production was lower during exercise. Muscle [glycogen] and pH were lower at rest, whereas heart rate, muscle pH and [lactate], and plasma [lactate] and [K+] were lower and plasma [Cl-] higher following exercise after acetazolamide treatment. These data demonstrate that acetazolamide treatment aggravates the CO2 retention and acidosis occurring in the horse during heavy exercise. This could negatively affect muscle metabolism and exercise capacity.

Physiological Considerations in the Design of Clothing and Protective Equipment for Extreme Environments and in Modeling Human Heat Exchange

2000 ◽  
Vol 44 (12) ◽  
pp. 2-796-2-799
Author(s):  
Victor S. Koscheyev
Keyword(s):  
Heat Exchange ◽  
Extreme Environments ◽  
Heat Content ◽  
Feedback System ◽  
Physiological Data ◽  
Accurate Information ◽  
Protective Equipment ◽  
New Era ◽  
Terrestrial Environments ◽  
Body Heat

A new era is commencing in which the design of clothing and protective equipment is increasingly taking into account physiological data about human functioning in extreme environments. In these conditions, there is an intensive influence of environmental factors on body systems. Physiological in combination with other types of countermeasures that provide comfort are necessary for stabilizing homeostasis. This approach is extremely important for the design of heavy protective equipment that is widely used in such conditions as space, harsh terrestrial environments, undersea, and in military situations. A physiological overview of the human body for design and modeling purposes is presented, relying on extensive research findings on human thermoregulation and heat exchange using an experimental water circulating plastic tubing garment with the capacity for simultaneous cooling/warming of different body areas. The fingers have great potential as an informative site for providing accurate information about actual body heat status, developing an automatic feedback system between body heat content and the reactivity of the cooling/warming system, and improving modeling approaches.

Efficacy of Two Methods for Reducing Postbypass Afterdrop

2000 ◽  
Vol 92 (2) ◽  
pp. 447-447 ◽  
Author(s):  
Angela Rajek ◽  
Rainer Lenhardt ◽  
Daniel I. Sessler ◽  
Gabriele Brunner ◽  
Markus Haisjackl ◽  
...  
Keyword(s):  
Sodium Nitroprusside ◽  
Core Temperature ◽  
Heat Content ◽  
Tissue Temperature ◽  
Control Group ◽  
Peripheral Tissues ◽  
The Core ◽  
Forced Air Warming ◽  
Forced Air ◽  
Body Heat

Background Afterdrop, defined as the precipitous reduction in core temperature after cardiopulmonary bypass, results from redistribution of body heat to inadequately warmed peripheral tissues. The authors tested two methods of ameliorating afterdrop: (1) forced-air warming of peripheral tissues and (2) nitroprusside-induced vasodilation. Methods Patients were cooled during cardiopulmonary bypass to approximately 32 degrees C and subsequently rewarmed to a nasopharyngeal temperature near 37 degrees C and a rectal temperature near 36 degrees C. Patients in the forced-air protocol (n = 20) were assigned randomly to forced-air warming or passive insulation on the legs. Active heating started with rewarming while undergoing bypass and was continued for the remainder of surgery. Patients in the nitroprusside protocol (n = 30) were assigned randomly to either a control group or sodium nitroprusside administration. Pump flow during rewarming was maintained at 2.5 l x m(-2) x min(-1) in the control patients and at 3.0 l x m(-2) x min(-1) in those assigned to sodium nitroprusside. Sodium nitroprusside was titrated to maintain a mean arterial pressure near 60 mm Hg. In all cases, a nasopharyngeal probe evaluated core (trunk and head) temperature and heat content. Peripheral compartment (arm and leg) temperature and heat content were estimated using fourth-order regressions and integration over volume from 18 intramuscular needle thermocouples, nine skin temperatures, and "deep" hand and foot temperature. Results In patients warmed with forced air, peripheral tissue temperature was higher at the end of warming and remained higher until the end of surgery. The core temperature afterdrop was reduced from 1.2+/-0.2 degrees C to 0.5+/-0.2 degrees C by forced-air warming. The duration of afterdrop also was reduced, from 50+/-11 to 27+/-14 min. In the nitroprusside group, a rectal temperature of 36 degrees C was reached after 30+/-7 min of rewarming. This was only slightly faster than the 40+/-13 min necessary in the control group. The afterdrop was 0.8+/-0.3 degrees C with nitroprusside and lasted 34+/-10 min which was similar to the 1.1+/-0.3 degrees C afterdrop that lasted 44+/-13 min in the control group. Conclusions Cutaneous warming reduced the core temperature afterdrop by 60%. However, heat-balance data indicate that this reduction resulted primarily because forced-air heating prevented the typical decrease in body heat content after discontinuation of bypass, rather than by reducing redistribution. Nitroprusside administration slightly increased peripheral tissue temperature and heat content at the end of rewarming. However, the core-to-peripheral temperature gradient was low in both groups. Consequently, there was little redistribution in either case.

scholarly journals Pharmacokinetic Optimisation of Aminophylline Infusions in Critically Ill Patients

1983 ◽  
Vol 11 (3) ◽  
pp. 220-227 ◽  
Author(s):  
K. F. Ilett ◽  
R. L. Nation ◽  
B. Silbert ◽  
T. E. Oh
Keyword(s):  
Critically Ill ◽  
Critically Ill Patients ◽  
Venous Blood ◽  
Plasma Concentrations ◽  
Sampling Time ◽  
Infusion Therapy ◽  
Plasma Theophylline ◽  
Total Body ◽  
Theophylline Kinetics ◽  
Body Clearance

The method of Chiou et al.4 was used to predict theophylline kinetics in eleven critically ill patients with either acute severe asthma or bronchoconstriction. Following the commencement of an accurately metered infusion of aminophylline, venous blood samples were taken at approximately 1, 5 hours and 7-12 hours for measurement of plasma theophylline concentration. The 1- and 5-hour levels were used to estimate total body clearance and plasma concentration of theophylline at the 7-12-hour sampling time. Using these values, the infusion rate was adjusted if necessary and the protocol repeated. Initial predictions were unreliable in two patients because of continued absorption of theophylline from pre-infusion therapy with aminophylline suppositories or slow-release theophylline tablets. In the remaining studies there was a significant correlation (y = 0.9x + 0.55, r2 = 0.93, p < 0.01, n = 19) between predicted and actual plasma concentrations at the 7-12-hour sampling time. In three patients, sequential estimates of theophylline clearance showed an approximate twofold variation and in another two patients, there was evidence of concentration-and/or time-dependent theophylline kinetics.

Temperature gradients in pigs during whole-body hyperthermia at 42 degrees C

1979 ◽  
Vol 47 (4) ◽  
pp. 712-717 ◽  
Author(s):  
J. A. Dickson ◽  
A. McKenzie ◽  
K. McLeod
Keyword(s):  
Core Temperature ◽  
Brain Temperature ◽  
Heat Content ◽  
Temperature Gradients ◽  
Whole Body ◽  
Induction Phase ◽  
Equilibrium Conditions ◽  
Repeated Heating ◽  
Deep Body ◽  
Body Heat

Temperature was simultaneously measured by thermistors in multiple deep-body and peripheral sites in adult pigs heated continuously at 42 degrees C (rectal) and above for 4–24 h. During hyperthermia, the relations between different body temperatures were maintained and up to 1.0 degrees C separated temperature measurements at sites such as liver and bone marrow. These persistent temperature gradients must be borne in mind when evaluating tumor response in patients subjected to whole-body heating for disseminated cancer. Temperatures recorded by rectal, deep esophageal, or tympanic membrane sensors provided a reliable index of core temperature (including brain temperature) under equilibrium conditions at 42 degrees C, but only esophageal and tympanic sensors could safely be used to monitor the induction phase of hyperthermia and the adjustive changes in body-heat content required to stabilize core temperature during sustained hyperthermia. Pigs withstood repeated heating at 42 degrees C for 6 h, and recovered rapidly, but died after 24 h of hyperthermia. Pigs subjected to unrestrained heating died at 45 degrees C (esophagus).

Relationship between body heat content and finger temperature during cold exposure

2001 ◽  
Vol 90 (6) ◽  
pp. 2445-2452 ◽  
Author(s):  
Dragan Brajkovic ◽  
Michel B. Ducharme ◽  
John Frim
Keyword(s):  
Skin Temperature ◽  
Heat Storage ◽  
Heat Content ◽  
The Body ◽  
Finger Temperature ◽  
Finger Dexterity ◽  
The Relationship ◽  
Finger Skin ◽  
Body Heat ◽  
Partitional Calorimetry

The purpose of the present experiment was to examine the relationship between rate of body heat storage (S˙), change in body heat content (ΔHb), extremity temperatures, and finger dexterity. S˙, ΔHb , finger skin temperature (Tfing), toe skin temperature, finger dexterity, and rectal temperature were measured during active torso heating while the subjects sat in a chair and were exposed to −25°C air. S˙ and ΔHb were measured using partitional calorimetry, rather than thermometry, which was used in the majority of previous studies. Eight men were exposed to four conditions in which the clothing covering the body or the level of torso heating was modified. After 3 h, Tfing was 34.9 ± 0.4, 31.2 ± 1.2, 18.3 ± 3.1, and 12.1 ± 0.5°C for the four conditions, whereas finger dexterity decreased by 0, 0, 26, and 39%, respectively. In contrast to some past studies, extremity comfort can be maintained, despite S˙ that is slightly negative. This study also found a direct linear relationship between ΔHb and Tfing and toe skin temperature at a negative ΔHb. In addition, ΔHb was a better indicator of the relative changes in extremity temperatures and finger dexterity over time than S˙.

Thermoregulation in swimmers and runners

1979 ◽  
Vol 46 (6) ◽  
pp. 1086-1092 ◽  
Author(s):  
R. G. McMurray ◽  
S. M. Horvath
Keyword(s):  
Oxygen Uptake ◽  
Heat Storage ◽  
Subcutaneous Fat ◽  
Heat Content ◽  
Volume Ratio ◽  
Heat Acclimatization ◽  
Vasomotor Control ◽  
Percentage Body Fat ◽  
Body Heat ◽  
Control Exercise

Thermoregulatory responses of six trained swimmers and five runners to cold and heat were evaluated during 30 min of exercise (60% VO2max) while immersed to the neck in 20, 25, 30, and 35 degrees C water. Mean oxygen uptake was similar for both groups during all four trials. Changes in metabolic rate during the 8th to 28th min were significantly greater for the runners in 20 degrees C water, and swimmers in 30 and 35 degrees C water. Heart rates, Tsk, delta Tre, Tb, body heat content, and heat storage were dependent on water temperature. Runners were able to attain higher sweat rates than swimmers in 35 degrees C water. Swimmers had significantly greater tissue conductance values in the 35 degrees C exposure. Swimmers thermoregulated better in 20 degrees C water than runners, possibly due to a larger surface area-to-volume ratio, percentage body fat, subcutaneous fat, or improved vasomotor control. Exercise in the heat was better tolerated by runners. Physical training in water does not improve heat acclimatization to the extent of training in air, but does improve cold tolerance.

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