Procedures
Depending on the severity of hypothermia, emergency medical care for hypothermia may include one of the following interventions to raise the body temperature: Passive rewarming. For someone with mild hypothermia, it is enough to cover them with heated blankets and offer warm fluids to drink. Blood rewarming.
Therapy
Rewarming is a delicate phase of therapeutic hypothermia (TH). Adverse consequences of rewarming on the whole body may seriously limit the protective effects of hypothermia, leading to secondary injury. Thus, understanding, predicting, and managing possible systemic side effects of rewarming is important for guaranteeing TH efficacy.
Nutrition
The literature shows that those patients that received a type of active rewarming in the postoperative period reached normothermia quicker than those in the control group, had higher satisfaction, and lower post anesthesia care unit (PACU) length of stay. Key words: Postoperative, warming, forced-air warming, radiant heat, hypothermia, rewarming.
How is hypothermia treated in the emergency room?
Bisschops LL, Hoedemaekers CW, Mollnes TE, van der Hoeven JG: Rewarming after hypothermia after cardiac arrest shifts the inflammatory balance. Crit Care Med. 2012, 40: 1136-1142. 10.1097/CCM.0b013e3182377050.
What is rewarming in therapeutic hypothermia?
Does rewarming in the postoperative period improve normothermia?
Does rewarming after hypothermia after cardiac arrest shift the inflammatory balance?
How do you rewarm a hypothermic patient?
A warmed intravenous solution of salt water may be put into a vein to help warm the blood. Airway rewarming. The use of humidified oxygen administered with a mask or nasal tube can warm the airways and help raise the temperature of the body.
How long does it take to warm the body after therapeutic hypothermia?
The therapeutic hypothermia will likely last around 24 hours. The medical team will slowly rewarm you over several hours. They may set cooling blankets at gradually higher temperatures. In some cases, they may use rewarming devices as well.
How is hypothermia corrected?
In cases of advanced hypothermia, hospital treatment is required to rewarm the core temperature. Hypothermia treatment may include warmed IV fluids, heated and humidified oxygen, peritoneal lavage (internal "washing" of the abdominal cavity), and other measures.
How long does it take to recover from severe hypothermia?
If fluids and rest do not resolve symptoms, a doctor will perform a blood work-up and other clinical tests to rule out other potential causes. If heat exhaustion is treated promptly, the individual will be fully recovered within 24-48 hours.
What happens to the body after resuscitation?
By nine minutes, severe and permanent brain damage is likely. After 10 minutes, the chances of survival are low. Even if a person is resuscitated, eight out of every 10 will be in a coma and sustain some level of brain damage. Simply put, the longer the brain is deprived of oxygen, the worse the damage will be.
Why it is important that you do not warm the body too quickly for a victim of hypothermia?
Warming the extremities first can cause shock. It can also drive cold blood toward the heart and lead to heart failure. DO NOT warm the victim too fast. Rapid warming may cause heart arrhythmias.
What happens after hyperthermia?
Patients who become acutely hyperthermic often display signs of neurological dysfunction. The neurological injury may manifest in several ways, including cognitive dysfunction, agitation, seizures, unsteadiness, or disturbance of consciousness from lethargy to coma.
What should you do after hyperthermia?
Try to get to a cool location, preferably one with air conditioning. Drink water or electrolyte-filled sports drinks. Take a cool bath or shower to help speed up your recovery. Place ice bags under your arms and around your groin area.
Can you defibrillate a hypothermic patient?
Generally, defibrillation is ineffective at hypothermic core temperatures and when equipment for heroic attempts at resuscitation is unavailable.
Can you come back from hypothermia?
Most healthy people with mild to moderate hypothermia fully recover. And they don't have lasting problems. But babies and older or sick adults may be more at risk for hypothermia. This is because their bodies do not control temperature as well.
Can a person recover from hypothermia?
Prognosis and Possible Complications. People with mild hypothermia usually recover with no lasting damage. However, people with moderate-to-severe hypothermia can face serious complications and even death. Children are more likely to recover from severe hypothermia than adults.
What are the after effects of hypothermia?
When your body temperature drops, your heart, nervous system and other organs can't work normally. Left untreated, hypothermia can lead to complete failure of your heart and respiratory system and eventually to death. Hypothermia is often caused by exposure to cold weather or immersion in cold water.
What is therapeutic hypothermia?
Therapeutic hypothermia is a type of treatment. It’s sometimes used for people who have a cardiac arrest. Cardiac arrest happens when the heart suddenly stops beating. Once the heart starts beating again, healthcare providers use cooling devices to lower your body temperature for a short time. It’s lowered to around 89°F to 93°F (32°C to 34°C).
Why might I need therapeutic hypothermia after cardiac arrest?
Therapeutic hypothermia can help only some people who have had cardiac arrest. Some people regain consciousness right after cardiac arrest. These people often do not need this procedure. It is helpful only for people whose heartbeat returns after a sudden cardiac arrest. If the heartbeat doesn’t restart soon, it won't help.
How long does it take to wake up after cardiac arrest?
It may take a couple of days. Healthcare providers often wait at least 3 days after the procedure to see how the cardiac arrest affected the brain. The procedure does not guarantee that you will regain brain function. Some people do eventually wake up after therapeutic hypothermia. They may not have any lasting brain injury.
How long does hypothermia last?
That’s when chilled fluids are given through an IV (intravenous) line into your bloodstream. The therapeutic hypothermia will likely last around 24 hours. The medical team will slowly rewarm you over several hours. They may set cooling blankets at gradually higher temperatures.
What kind of care do you need for a cardiac arrest?
You will need follow-up care . Medical care will depend on the reason for the cardiac arrest and the degree of damage. Other health problems you have will also determine the care you need. You may need medicine, procedures, and physical therapy. Some people might need surgery for heart disease.
What is the best way to check your temperature?
Your heart rate, blood pressure, and other vital signs will be closely watched. Healthcare providers use special thermometers to check your internal temperature. The provider may use cooling blankets, ice packs, or cooling pads to bring the body temperature down. The goal is to cool as quickly as possible.
Is hypothermia dangerous?
Therapeutic hypothermia is very helpful for some people. But it has some rare risks. Some of these risks include: Another abnormal heart rhythm, especially slow heart rates. Severe blood infection (sepsis) Blood is less able to clot. This can cause bleeding. Electrolyte and metabolic problems.
How to act quickly when you have hypothermia?
Regardless of the cause or your certainty of a case of hypothermia, if you are with someone who is experiencing signs and symptoms —low heart rate and shallow respiration are particularly concerning—you need to act quickly by first stopping the loss of body heat.
How does hypothermia happen?
Hypothermia occurs when the core body temperature—the temperature of the organs and blood in the center of the body, not the skin—drops below 95 degrees. This may happen in a number of situations, such as when someone is out in cold weather for too long or falls into icy water. People who are wet will lose body heat faster ...
What is hypothermia in 2021?
Updated on June 23, 2021. Hypothermia is a medical emergency in which your body loses heat faster than it can produce it, causing a dangerous drop in the core body temperature.
What is the temperature of a person with moderate hypothermia?
Moderate hypothermia is defined as a body temperature of 82.4 to 89.9 degrees F (28 to 32.2 degrees C) with slower breathing and heart rate, dilated pupils, decreased reflexes, and low blood pressure. Severe hypothermia is a body temperature of less than 82.4 degrees F (28 degrees C) and nonreactive pupils, heart failure, difficulty breathing, ...
What are the stages of hypothermia?
Hypothermia stages include mild, moderate, and severe . Mild hypothermia is characterized by a body temperature of 90 to 95 degrees F (32.2 to 35 degrees C) and shivering, rapid breathing, increased heart rate, and lack of coordination. Moderate hypothermia is defined as a body temperature of 82.4 to 89.9 degrees F (28 to 32.2 degrees C) with slower breathing and heart rate, dilated pupils, decreased reflexes, and low blood pressure. Severe hypothermia is a body temperature of less than 82.4 degrees F (28 degrees C) and nonreactive pupils, heart failure, difficulty breathing, and cardiac arrest. 5
What is passive external rewarming?
Passive external rewarming (PER) is typically used to treat mild hypothermia. It simply involves placing the individual in an appropriately warm environment, covered in insulation, and gradually raising the core body temperature a few degrees every hour.
How to protect yourself from a cold?
Cut away the clothing if you need to and immediately cover the person with dry blankets or coats. Be sure to cover the person's head, leaving the face exposed. Insulate the person from the cold ground if you are unable to get indoors. Use blankets, sleeping bags, or whatever clothing you may have on hand. Call 911.
What is thermoregulation in anesthesia?
In the non-anesthetized patient, thermoregulation is a three-phase process involving afferent thermal sensing, central regulation, and efferent responses. Peripheral sensors send messages to the brain via the anterior spinal cord to various regions including the hypothalamus regarding body temperature changes. Normothermia is maintained with behavior modifications including seeking warmth and layer clothing. General anesthesia hinders the patient from normal thermoregulatory mechanisms and thus requires the body to rely solely on autonomic efferent responses to adjust temperature back to normal range, such as shivering, sweating, and vasoconstriction. However, general anesthesia (GA) also inhibits the body’s shivering and vasoconstriction capacity which may compound hypothermia.GA causes peripheral vasodilation which forces the cooler peripheral blood back to the central compartments resulting in a decrease in body temperature. 5
What is an intervention in a postoperative period?
Any intervention meant to restore normal body temperature during the postoperative period compared with usual care or another intervention. Interventions included: active warming devices, thermal insulation or passive warming devices, warming of IV fluids, warming of irrigation fluids and warming of inspired gases.
Does general anesthesia cause hypothermia?
However, general anesthesia (GA) also inhibits the body’s shivering and vasoconstriction capacity which may compound hypothermia.GA causes peripheral vasodilation which forces the cooler peripheral blood back to the central compartments resulting in a decrease in body temperature. 5.
Is hypothermia a common occurrence in surgical patients?
Postoperative hypothermia is a common occurrence for surgical patients and can be associated with a higher morbidity and mortality rate. 3 Current literature recommends a number of rewarming methods to counteract hypothermia in the immediate postoperative period. Hospitals and healthcare providers are incorporating these methods into their practice to improve patient outcomes and to provide safe and effective patient care.
Is perioperative hypothermia a rewarming?
The literature from 2008-2016 was reviewed to aid in building the knowledge development of postoperative patient temperature monitoring and maintenance in the adult surgical patient. The results demonstrated that active rewarming is superior to the conventional warmed cotton blanket. The literature shows that those patients that received a type of active rewarming in the postoperative period reached normothermia quicker than those in the control group, had higher satisfaction, and lower post anesthesia care unit (PACU) length of stay.
Is hypothermia a concern?
Perioperative hypothermia is a serious concern in regards to patient safety and its prevention should be a goal of all surgical staff. Postoperative decreases in patient temperature can lengthen stay, increase costs, and decrease comfort and satisfaction. Determining the most effective and efficient method for postoperative rewarming was the goal of this literature review.
What should be optimized during rewarming?
Third, oxygen content and transport should be optimized. Anemia and arterial desaturation must be avoided during rewarming. To date, no clinical trials have examined hemodynamic optimization in patients that have undergone TH, least of all during rewarming, and no evidence is currently available to indicate the best strategy for hemodynamic support in such a critical phase. We suggest a strict control of hemodynamics, with the aim of guaranteeing adequate oxygen delivery and avoiding VO 2 /DO 2 mismatch, using at least continuous arterial pressure monitoring, volume balance and urine output surveillance, and frequent serum lactate measurements. In the case of hemodynamic instability, advanced monitoring capable of finer management could be useful. Thus, in this context, echocardiography and goal-directed hemodynamic optimization [ 34] may have a place. Treatment of systolic left ventricular impairment presents additional concerns. Pharmacological therapy with catecholamines presents substantial limitations [ 35, 36 ], as the decreased myofilament Ca 2+ sensitivity during rewarming significantly diminishes β-adrenoceptor effects. In addition, catecholamines determine elevated myocardial oxygen consumption and arrhythmogenesis. A recent study by Rungatscher and colleagues [ 37] tested the efficacy of levosimendan in improving myocardial dysfunction after rewarming from deep hypothermia in a rat model. Levosimendan, as a Ca 2+ sensitizer, demonstrated better inotropic and lusitropic effects than epinephrine.
What is rewarming in TH?
Rewarming is a delicate phase of therapeutic hypothermia (TH). Adverse consequences of rewarming on the whole body may seriously limit the protective effects of hypothermia, leading to secondary injury. Thus, understanding, predicting, and managing possible systemic side effects of rewarming is important for guaranteeing TH efficacy. The aim of this brief report is to describe rewarming effects from a systemic perspective.
Why does rewarming shock occur after TH?
In more recent studies, rewarming shock after moderate TH seems to be a more infrequent eventuality, probably because TH management has been completely changed by the advent of ICUs and a far less hypothermic regimen.
How does rewarming affect oxygen supply?
The experiment demonstrated a reduction in cardiac output and oxygen delivery after prolonged deep hypothermia (15°C for 5 hours) compared with less prolonged exposure. The rewarming-related rightward shift of the oxygen hemoglobin saturation curve, which facilitates oxygen dissociation at the tissue level , compensated for compromised peripheral oxygen transport, leading to a stable oxygen supply. Knowing the events causing VO 2 /DO 2 mismatch during rewarming is important in this phase of TH for monitoring and assuring adequate cerebral and whole body oxygen delivery. Low oxygen delivery accounts for the development of secondary injury, which limits the safety and effectiveness of TH. With this perspective in mind, we can suggest various measures to limit VO 2 /DO 2 mismatch during rewarming.
What temperature does platelet dysfunction occur?
Mild platelet dysfunction occurs at temperatures <35°C, and some inhibition of the coagulation cascade develops at temperatures <33°C. In TH after TBI [ 58] and stroke [ 57 ], the platelet count can also decrease, which persists during and after rewarming. In neonatal cold injury, death occurring during rewarming has been attributed to massive thrombosis from platelet hyperaggregation [ 60 ].
Does hypothermia cause potassium to increase?
Mild hypothermia shifts potassium inside the cells and predisposes the patient to hypokalemia, as well as hypocalcemia, hypomagnesemia, and hypophosphatemia. During rewarming, rebound increases in these electrolytes (particularly potassium) may occur, especially if they were replaced excessively during the cooling period [ 46 ]. Hyperkalemia can be prevented by slow and controlled rewarming, allowing the kidney to excrete the excess potassium. In patients with severe oliguria or anuria, renal replacement therapy should be started before rewarming to avoid hyperkalemia.
Is rewarming from TH a dynamic insulin/glucose ratio?
Passive rewarming from TH increases insulin sensitivity, but active rewarming from cardiopulmonary bypass decreases it. In both settings, rewarming is characterized by a dynamic insulin/glucose ratio; glucose should be checked frequently and insulin requirements promptly adapted to achieve optimal glycemic control.
What is the response to hypothermia?
Shivering is a thermoregulatory response to hypothermia that occurs when the core body temperature decreases below 36.5 degrees C. Shivering produces heat through the rhythmic contraction and relaxation of skeletal muscle, which increases oxygen consumption, energy expenditure, and induction time. These changes counteract many of the beneficial effects of therapeutic hypothermia; therefore, shivering must be suppressed to ensure maximal benefit from hypothermia. This is achievable through various pharmacologic and non-pharmacologic interventions.
When was hypothermia first used?
In the early 1800s, during the French invasion of Russia, a battlefield surgeon noticed that wounded soldiers placed closer to campfires died sooner than those placed in colder bunks. During this period, cryoanalgesia was also used for amputations, and surgeons noticed that hypothermia not only acted as an analgesic but also slowed bleeding. Clinical interest in the application of therapeutic hypothermia began in the 1930s with case reports on drowning victims who were resuscitated successfully despite prolonged asphyxia. [1]
How does hypothermia affect the body?
Hypothermia causes a linear decrease in the metabolic rate by 5% to 7% per 1 degree Celsius decrease in core body temperature. A left shift in the oxygen hemoglobin dissociation curve reduces tissue oxygen availability and may contribute to the development of metabolic acidosis (Schubert (1995)). Oxygen consumption and CO2 production are equally decreased. If ventilator settings are not properly adjusted, decreased CO2 production may promote respiratory alkalosis and hypocapnia. This results in cerebral vasoconstriction increased cerebral vascular resistance and decreased cerebral blood flow. Pharmacokinetic and pharmacodynamic alterations in drug metabolism can occur in patients receiving therapeutic hypothermia. These patients receive multiple drugs during their treatment course, including paralytics, anticonvulsants, sedatives, and cardiovascular drugs. Unanticipated drug toxicity may occur due to changes in metabolism, especially since many of these drugs have a narrow therapeutic window. The mechanisms involved in these changes are drug-specific and can occur in one or more of the different phases of drug metabolism, response, or elimination. Clinical studies evaluating the effect of hypothermia on the metabolism of specific drugs found that for many commonly used drugs such as propofol, vecuronium, rocuronium, midazolam, and phenytoin, there was an increase in serum concentration, decrease in clearance rate, and increase in the duration of action.[18] Metabolism gradually returned to baseline during the rewarming phase. This suggests that doses should be lowered to prevent toxicity. TH may be associated with decreased insulin sensitivity and decreased insulin secretion by pancreatic islet cells. It has been shown that hyperglycemia is associated with poor neurological outcomes and increased mortality. [19][20]However, it is unclear whether the hyperglycemia is due to hypothermia or due to the initial stress of cardiac arrest and the resultant organ hypoperfusion. Some studies show that therapeutic hypothermia does not have an independent effect on glucose homeostasis, and when compared with normothermic patients, blood glucose levels only differs between the period of cardiac arrest and the initiation of hypothermia treatment.[21] These conflicting results raise the question of whether hyperglycemia affects neurological outcome and survival directly, or simply that the glucose level is proportional to the severity of initial neurological damage, which would be associated with a less favorable outcome.
Why is rewarming important?
The rewarming phase may also be associated with electrolyte disturbances. Hyperkalemia often occurs in this phase due to the release of intracellular potassium and may result in cardiac arrhythmias. Rewarming the patient at a slow and controlled rate can prevent this complication by giving the kidneys more time to excrete the excess potassium. [16]
How does hypothermia affect brain function?
The three main temperature-dependent pathological processes that hypothermia acts on are ischemic brain injury, reperfusion injury, and secondary brain damage.[4] Hypothermia decreases the metabolic rate by 5% to 7% per 1 C decrease in core body temperature. [5] This is one of the main mechanisms underlying its protective effects since oxygen deprivation and the accumulation of lactate and other waste products of anaerobic metabolism are central to the progression of ischemic cerebral cell death. The accumulation of aspartate, glutamate, and other excitatory neurotransmitters also plays a significant role in neuronal death following cerebral ischemia. The severity of excitotoxicity and neuronal damage is proportional to the quantity of these neurotransmitters.[6] In animal models, it was shown that the release of glutamate following global cerebral ischemia is temperature-dependent. A mild to moderate hypothermia is associated with the most profound reduction in glutamate levels compared to severe hypothermia and hyperthermia.[7] Hypothermia decreases free radical production and suppresses the various inflammatory processes that occur following global ischemia and reperfusion.
How does hypothermia induction work?
Induction of hypothermia is the process in which a target core temperature of 32 to 34 degrees Celsius is reached as quickly as possible . This is achievable through several different external and internal cooling mechanisms. Hypothermia induction may be started in the ambulance or once the patient arrives at the hospital. Although it was thought that earlier cooling by paramedics en route to hospital would result in improved outcomes due to more rapid attainment of target temperature, this was not the case in some studies. One randomized controlled trial assigned 234 patients resuscitated from out of hospital cardiac arrest to either prehospital cooling or cooling after admission.[11] The prehospital cooling was performed by paramedics using a rapid infusion of 2 liters of ice-cold (4 degrees C) lactated Ringers solution and was found to decrease core temperature by an average of 0.8 degrees C (P=0.01). However, the earlier achievement of target temperature was not associated with improved outcomes at hospital discharge. The RINSE trial (Rapid Infusion of Cold Normal Saline) found that out-of-hospital patients with cardiac arrest who received cold saline during CPR had reduced rates of ROSC and provided no improvement in outcomes at hospital discharge. These results conflict with results from animal trials in which earlier cooling improved outcomes, raising questions about when cooling should be commenced for optimal outcomes.
What is the HACA trial?
This trial was one of the first randomized controlled studies evaluating the effects of therapeutic hypothermia on comatose survivors of out-of-hospital cardiac arrest. This trial, along with the HACA trial, was pivotal to hypothermia, establishing its place in resuscitation guidelines. The study was performed in Melbourne, Australia, between September 1996 and June 1999. Seventy-seven patients were enrolled based on specific criteria, including the initial rhythm of ventricular fibrillation, the successful return of spontaneous circulation (ROSC), and persistent coma after resuscitation. Patients with cardiac arrest of presumed noncardiac etiology were excluded, along with patients with cardiogenic shock, males under the age of 18, and females under the age of 50.
