CONTROL OF INTRAOPERATIVE SHIVERING UNDER SPINAL ANAESTHESIA- A PROSPECTIVE RANDOMIZED COMPARATIVE STUDY OF NALBUPHINE WITH TRAMADOL

spinal anesthesia is a widely used technique for both elective and emergency surgeries. Shivering is one of the most commonly recognized complications of the central neuraxial blockade because of impairment of thermoregulatory control, reported in 40%-70% of the patients undergoing surgery under spinal anaesthesia. Post-anesthetic shivering is defined as an involuntary,spontaneous,rhythmic oscillating muscle hyperactivity that increases metabolic heat production up to 600% after anesthesia. Shivering during neuraxial anesthesia is a common issue that could have possibly adverse impacts, for example, increased oxygen consumption, carbon dioxide production, lung ventilation and cardiac work, as well as causing diminished mixed venous oxygen saturation. Spinal anesthesia impedes the thermoregulatory system by restraining tonic vasoconstriction which assumes significant role in the regulation of temperature

Comparison of Efficacy of Intravenous Tramadol versus Normal Saline in Suppression of Postoperative Shivering in Patients undergoing Elective Surgery

Background: Shivering in the post anesthesia care unit is a common and distressing complication for patients after receiving general or regional anesthesia. Perioperative hypothermia has been associated with an increase in morbidity and mortality. Both central and peripheral thermoregulation is impaired by regional anesthesia. Thermoregulatory system synchronizes with defense system to maintain body’s heat and coolness within the narrow range, thus improving the normal functioning. Objective: To compare the efficacy of intravenous tramadol versus normal saline in suppression of postoperative shivering in patients undergoing elective surgery. Design: It was a randomized control trial. Study Settings: Trial was conducted at Department of Anesthesiology and ICU, Sheikh Zayed Hospital, Lahore, for a period of one year w.e.f 7-11-2019 to 7-11-20. Patients and Methods: A total of 50 patients with age 18 years and above from both the genders undergoing elective surgery under general anesthesia were included in the study and divided into two equal groups randomly. Patients in tramadol group were given tramadol 0.5mg/kg I/V and patients of control group were given 0.9% normal saline 5ml I/V. Results: In tramadol groups the mean age of patients was 27.88±2.79 years while the mean age of the patients from placebo group was 27.84±4.23 years. In this study the efficacy was achieved in 37(74.0%) patients. In control group the efficacy was achieved in 15(60%) patients and in tramadol group the efficacy was achieved in 22(88.0%) patients (p-value<0.05). Conclusion: According to this study the intravenous tramadol is safe and effective drug in suppression of postoperative shivering in patients undergoing elective surgery under spinal anesthesia. Keywords: Intravenous Tramadol, Spinal Anesthesia, Shivering, Elective Surgery.

Dorsomedial hypothalamic BDNF neurons integrate thermal afferent signals to control energy expenditure

Mutations in the gene brain-derived neurotrophic factor (BDNF) cause obesity in humans. BDNF signaling and its expressing neurons in the hypothalamus help control feeding, energy expenditure (EE), and physical activity. However, whether the BDNF neurons interact with another EE-regulating system, the thermoregulation circuitry, remains unclear. Here, we show that BDNF neurons in the dorsomedial hypothalamus (DMH) are activated by environmental cooling and sufficient to induce body temperature increases and brown adipose tissue (BAT) thermogenesis. Conversely, blocking these neurons impairs BAT thermogenesis and cold defense, causing body weight gain and glucose intolerance. DMH BDNF neurons are therefore an important type of thermoregulatory neuron, integrating thermal afferent signals to control EE during cold defense. This reveals a critical intersection between the BDNF circuitry and the thermoregulatory system.

Temperature management and its role in cardiac arrest patients—a review

Thermoregulation constitutes one of the most important homeostatic systems of the human body. The human thermoregulatory system is highly complex and intertwined with other regulatory homeostatic systems. Different evolutionary adaptations have evolved to ensure a well-regulated body temperature, encompassing simple behavioural (e.g., seeking shelter, going underground) as well as physiological changes (e.g., vasodilatation, sweating). However, when the heat, cold or other stimuli cause a disruption in the thermoregulatory state and our adaptations can no longer cope with the additional stress, the body enters a pathological state. In such instances other measures must be undertaken. In medicine there are several pathological states associated with disruptions in temperature homeostasis. Consequently, these patients have to be, in broad terms, thermoregulated. Speaking specifically, the most common application of thermoregulation is therapeutic temperature management. A prominent example is the utilisation of this technique in post-cardiac arrest patients, who remain comatose after resuscitation. This technique has been in use for almost 20 years since the first major reports on its benefits in improving out-of-hospital cardiac arrest and in-hospital cardiac arrest survival as well as improving neurological outcome. Recently, the findings from one of the biggest targeted temperature international and multicentre trials to date have been published (TTM2 trial; https://ttm2trial.org/). The study surprisingly showed no difference in mortality between patients after out of hospital cardiac arrest, who underwent normo- or hypothermia. Consequently, we might need to re-evaluate certain guidelines, recommendations, and perspectives. The aim of the current review is to present an overview of targeted temperature management in the field of intensive care medicine and cardiac arrest.

CNGA3 acts as a cold sensor in hypothalamic neurons

Most mammals maintain their body temperature around 37°C, whereas in hibernators it can approach 0°C without triggering a thermogenic response. The remarkable plasticity of the thermoregulatory system allowed mammals to thrive in variable environmental conditions and occupy a wide range of geographical habitats, but the molecular basis of thermoregulation remains poorly understood. Here we leverage the thermoregulatory differences between mice and hibernating thirteen-lined ground squirrels (Ictidomys tridecemlineatus) to investigate the mechanism of cold sensitivity in the preoptic area (POA) of the hypothalamus, a critical thermoregulatory region. We report that, in comparison to squirrels, mice have a larger proportion of cold-sensitive neurons in the POA. We further show that mouse cold-sensitive neurons express the cyclic nucleotide-gated ion channel CNGA3, and that mouse, but not squirrel, CNGA3 is potentiated by cold. Our data reveal CNGA3 as a hypothalamic cold sensor and a molecular marker to interrogate the neuronal circuitry underlying thermoregulation.

Concept of Microclimate in Russian Legislation

In the constantly changing conditions of the external environment, the microclimate is supported by the stabilizing systems of the building in the overall system ”building - exterior fences and engineering equipment”. To create a comfortable microclimate in the room, special systems are used: heating, ventilation, and humidification. To create thermal comfort indoors means ensuring its complex meteorological conditions in which the thermoregulatory system of the body is in a state of the least tension, and all the other physiological functions occur at the level most beneficial for the body. In the modern world the quality of the indoor environment is a priority, part of the requirements is reflected in the modern standards of green building, part in the national standards. So the Russian Federation has legislative and normative-legal acts, reflecting the characteristics of environmental quality: GOST (State Standard) 30494-2011, SanPiN (Sanitary Regulations and Norms) 2.1.2.1002-00, GOST R ISO (Russian National Standard) 7730-2009, SN 2605-82, SNiP (Construction Standards and Regulations) 23-05-95 and others. Normalized microclimatic indicators include temperature, humidity and air velocity, surface temperature of building envelopes, objects, equipment. But at the present stage, the formation of a harmonized and safe environment of the room depends on many factors, which should not only reflect functional, social, climatic, urban planning, construction design, architectural-artistic and economic characteristics, but also socio-psychological and environmental components of the room.

Effects of heat on behavioral and physiological mechanisms of the human thermoregulatory system during rest, exercise, and work

Ο σκοπός αυτής της διατριβής ήταν να διευρύνει την υπάρχουσα γνώση στο πεδίο του θερμικού στρες και την αυτού με την ανθρώπινη φυσιολογία, γνωστική λειτουργία, συμπεριφορά και ικανότητα για φυσική δραστηριότητα. Για την επίτευξη του παραπάνω στόχου, διεκπεραιώθηκαν δύο συστηματικές ανασκοπήσεις της υπάρχουσας βιβλιογραφίας και συλλέχθηκε πληθώρα φυσιολογικών δεδομένων από εκατοντάδες άτομα που έκαναν φυσική δραστηριότητα σε διάφορα περιβάλλοντα. Μία σειρά από μελέτες παρατήρησης και παρέμβασης στο πεδίο, καθώς επίσης και εργαστηριακές μελέτες διεξάχθηκαν στην Κύπρο, τη Δανία, την Ελλάδα, το Κατάρ και την Ισπανία. Επιπρόσθετα δεδομένα παραχωρήθηκαν από την Αυστραλία, τον Καναδά, τη Σλοβενία και τις Ηνωμένες Πολιτείες Αμερικής. Η δουλειά αυτή οδήγησε στη συγγραφή εφτά μελετών οι οποίες παρουσιάζονται σαν διαφορετικά κεφάλαια της παρούσας διατριβής. Συνοψίζοντας, τα αποτελέσματα της παρούσας διατριβής δείχνουν ότι το περιβαλλοντικό στρες επηρεάζει την ανθρώπινη υγεία, φυσιολογία, γνωστική λειτουργία και την ικανότητα για φυσική δραστηριότητα, οδηγώντας σε σημαντικές οικονομικές επιπτώσεις οι οποίες αναμένεται να αυξηθούν στις επόμενες δεκαετίες. Η εργασία σε περιβάλλον με υψηλή ηλιακή ακτινοβολία οδηγεί σε αυξημένα επίπεδα θερμικής καταπόνησης και μείωση της γνωστικής λειτουργίας, ακόμη και σε περιπτώσεις στις οποίες το θερμικό στρες θεωρείται ίδια έντασης αλλά χωρίς την παρουσία ηλιακής ακτινοβολίας. Η ενθάρρυνση ατόμων που παράγουν έργο στη ζέστη για αυτορρύθμιση της έντασης έχει βαρύνουσα σημασία. Επιπρόσθετα, παρεμβάσεις που στοχεύουν στη μείωση του παραγόμενου έργου (αύξηση της μηχανοποίησης και παραχώρηση διαλειμμάτων), καθώς επίσης και στρατηγικές εν/υδάτωσης, κατανάλωσης τριμμένου πάγου και παραχώρησης κατάλληλου ρουχισμού μπορούν να διαδραματίσουν σημαντικό ρόλο ως ασπίδα προστασίας κατά του θερμικού στρες. Η χρήση κατάλληλων δεικτών θερμικού στρες θα μπορούσε να δράσει σαν ένα επιπρόσθετο μέτρο πρόληψης στοχεύοντας στην προάσπιση της ανθρώπινης υγείας και ευεξίας.

Clinical and Experimental Study on Thermoregulatory System and its Relation with Vasomotor Rhinitis

Introduction Much of the perennial cold are of vasomotor origin still a less appreciated phenomenon even among the medical personnel, much of which is dubbed in a cursorily in the clinical analogue of a west paper wrap as ‘allergic rhinitis’. This study was attempted to find out the role of thermoregulatory system with causation of vasomotor rhinitis and assessing role of hypothalamus in causation of vasomotor rhinitis. Materials and Methods In this study conducted during the period of July 1987 to August 1988, 20 normal adult individuals were taken as control and thermoregulatory study was done on them. The results were compared with cases of vasomotor rhinitis/non-allergic rhinopathy cases. In experimental study thermoregulatory study was done on albino rats before and after stereotaxis of anterior and posterior hypothalamic nuclei and the result were compared before stereotaxis and post stereotaxis. Results Among human study in clinical subjects, patient suffering from vasomotor rhinitis showed a definite shift towards thermoregulatory imbalance both for generalized body caloric fluctuation and particularly on the nasal mucosa. Post-vidian neurectomy results for thermoregulation test was highly significant. In animal study post-hypothalamic stereotaxis temperature measurement showed minimal depression. Dorsal anterior hypothalamic lesion ablation showed significant derangement in the thermoregulatory tolerance profile of the rats’ belly temperature. Posterior hypothalamic lesion showed that there may be some amount of derangements in the thermoregulatory tolerance, which however is not statistically conclusive. Thermoregulatory control is done at hypothalamus, particularly at anterior hypothalamic nuclei level and posterior hypothalamic nuclei in the brain. Thermoregulatory study proves a close correlation between non allergic rhinitis with imbalance in central thermal regulation by hypothalamus. Conclusion Thermoregulatory study in control and clinical subjects proves a close correlation between vasomotor rhinitis and sympathetic, parasympathetic system.