Therapeutic Hypothermia Ralph Quinones Grand Canyon University NRS410V January 17, 2010 jackQtoo@yahoo.com
Contents Therapeutic Hypothermia (TH) Time Line Sudden Cardiac Arrest (SCA) Statistics Basic Pathology of SCA Advantageous Effects of Therapeutic Hypothermia (TH) Other Effects of Therapeutic hypothermia TH Mortality Results and Outcomes TH Impacts on Nursing
Therapeutic Hypothermia (TH) Time Line In 1803, Russians attempted to use hypothermia therapeutically when they covered patients with snow in an attempt to resuscitate them (Liss, 1981). In the late 1930’s, hypothermia was studied in cancer patients with the hope that it would slow the division of cancer cells (Smith & Fay, 1940). 1959, the first study that addressed TH in cardiac arrest patients was published (Benson, Williams, Spencer, & Yates, 1959). Studies slowed down until the 1990’s (Koran, 2009). In 2003 the International Liaison Committee on Resuscitation adopted recommendations for the use of TH (Pyle, Pierson, Lepman, & Hewett, 2007). “In Dec. 2005, to improve survival rates, the American Heart Association published resuscitation recommendations for using mild hypothermia” (Pyle et al., 2007, P.32).
Therapeutic Hypothermia (TH) Time Line In 2008 a handful of American cities incorporate TH protocols into their Emergency Medical Services (EMS): Seattle, Boston, Miami, Vienna, and London England (Hertocollis, 2008). In Jan. 2009 New York City starts TH protocols and requires EMS to transport, TH patients, to facilities practicing TH only (Hertocollis, 2008). In December 2009 the City of Las Vegas adopted TH protocols into it’s EMS. In December 2009 Valley Hospital, Las Vegas educates Emergency Room and Medical Intensive Care Unit Personnel on TH. In December 2009 Ralph Quinones states, “Therapeutic hypothermia is like rediscovering CPR!” (J. R. Quinones, personal communication, December, 2009). Jan. 2010 Ralph Quinones has participated in 3 TH therapies since Valley Hospital initiated a TH protocol.
Sudden Cardiac Arrest (SCA) Statistics Each year in the United States of America: 310,000 people die of sudden cardiac arrest 375,000-750,000 people are resuscitated About 40% of those resuscitated will have a return of spontaneous circulation (ROSC) 30% of survivors have severe brain damage (Koran, 2009, P.49). SCA 2004 survival rates (no TH): 8.4% for all cardiac arrests 17.7% for Ventricular-Cardiac arrest (Pyle et al., 2007, P.32).
Basic Pathology of SCA Immediate cessation of blood flow to the brain results in: Decrease in cerebral oxygen Neurons become hypoxic within 20 seconds Central nervous system affected in first 5 min. 30% of cerebral blood flow is returned with CPR Only 50% of cerebral blood flow returns within 12 hours of resuscitation (Koran, 2009, P.49).
Basic Pathology of SCA Even after cerebral blood flow returns to baseline there is: Generation of oxygen free radicals Inflammatory cell invasion Ion imbalances Increased metabolic rate Increase in cellular oxygen demand (Koran, 2009, P.49).
Basic Pathology of SCA The goal of TH is to preserve brain tissue, neurological function, and a productive life post cardiac arrest. An unknown source stated that 1:5 TH therapies preserve brain tissue and some function. This unknown source also stated that 1:7 TH therapies preserve brain tissue, neurological function and a productive life post cardiac arrest.
Advantageous effects of Therapeutic hypothermia (TH) TH counteracts some negative physiologic effects by: Lowering body temperature Decreasing metabolic demand Decreasing cellular oxygen demand Decreasing intracranial pressure: Vasoconstriction Chronotropic effects (Koran, 2009, P.49).
Other Effects of Therapeutic hypothermia Decreased cardiac output/Cardiac index Increased Systemic vascular resistance Prolonger PR, QRS, and QT intervals Decreased CO2 production High risk for aspiration pneumonia Slowed peristalsis Diuresis Impaired immune function Impaired platelet function Risk for skin injury Electrolyte shifts Hyperglycemia Elevated lactate level Shivering Drug clearance is prolonged (NLK & Valley Hospital,2009).
TH Mortality Results and Outcomes In a randomized controlled trial of 275 patients Hypothermia group 41% Mortality rate at 6 months 55% improvement in Neurologic outcome Normothermia group 55% Mortality rate at 6 months 39% improvement in Neurologic outcome (Pyle et al., 2007, P.33).
TH Mortality Results and Outcomes 77 randomly assigned therapeutic hypothermia patients: Pre-hospital cardiac arrest survivors Hypothermia group • 49% survival with good outcomes (Pyle et al., 2007, P.33). Normothermia group • 26% survival with good outcomes (Pyle et al., 2007, P.33).
TH Impacts on Nursing Theoretically, TH protocols can be started by EMS in the field or in the emergency room, ideally, the patient should be in mild hypothermia (33*C) within an hour of arrest. However, the optimal time to start TH is within the first five hours post SCA (Hertocollis, 2008). Therapeutic hypothermia is achieved with Mild hypothermia (32-34*C).
TH Impacts on Nursing Identifying the indications and contraindications Differentiate the methods for inducing mild TH Safety issues and risks for mild TH Appropriate care for patients receiving TH after SCA (Pyle et al., 2007, P.33).
TH Impacts on Nursing Indications: • SCA with ROSC • 18 years or older • Persistent coma • No eye opening to pain • No response to tactile stimuli • Glasgow Coma Scale (GCS) < 8 • SBP>90 mmHG with or without fluids and vasopressors (Valley Hospital, 2009). Contra Indications: Pregnancy Severe coagulopathy Other causes of coma Pediatrics Trauma (Valley Hospital, 2009).
TH Impacts on Nursing Maintain Temperature @ 33*C (91.4*F) X 24 hours SBP > 90 mmHG MAP > 80 mmHG Sedation & Paralysis Re-warm @ 0.3-0.5*C per hour X 12 hours Central line access Monitor Temperature via Foley For hypokalemia during cooling For hyperkalemia during re-warming Ramsey Sedation Scale Bispectral Index (BIS) (Valley Hospital, 2009).
TH Impacts on Nursing Bispectral index (BIS) is “no longer used only in the OR.BIS monitoring can now be used to help ensure that a patient is sedated safely and effectively” BIS index is a measure of hypnotic effects of sedatives and anesthetics on the brain through EEG data. The BIS works on a scale of 0-100, where 0=no brain activity, 100=awake and alert, and with a BIS <60 a patient is not likely to be awake (Luebbehusen, 2005).
TH Impacts on Nursing With EMS protocols in place mild hypothermia is achieved within one hour of SCA and ROSC by: Early CPR Early Defibrillation Intubation, sedation & paralysis EMS placing ice packs at pressure points (Auxillary, femoral, etc…) Cold (4*C) normal saline infusion of 30 ml/kg (max 4 liters) wide open, or in a pressure bag Foley catheter with thermometer Cooling blanket to maintain mild hypothermia
References Benson, D. W., Williams, G. R., Jr., Spencer, F. C., & Yates, A. J. (1959). The use of hypothermia after cardiac arrest. Anesthesia & Analgesia, 38, 423-428. Hertocollis, A. (2008, December 4). City pushes cooling therapy for cardiac arrest. The New York Times, pp. Unknown. Koran, Z. (2009). Therapeutic hypothermia in the post-resuscitation patient: The development and implementation of an evidence- based protocol for the emergency department. Journal of Trauma Nursing, 16(1), 48-57. Liss, H. P. (1981) A history of resuscitation. Annals of Emergency Medicine, 15, 65-72. Luebbehusen, M. (2005). Technology today: Bispectral index monitoring [Online exclusive]. RN Web. Retrieved Unknown, from Unknown
References NLK, & Valley Hospital, (2009). [Medical cardiac ICU therapeutic hypothermia: Physiologic changes and nursing considerations]. Unpublished raw data. Pyle, K., Pierson, G., Lepman, D., & Hewett, M. (2007). Keeping cardiac arrest patients alive with therapeutic hypothermia: How to develop a successful protocol. American Nurse Today, 2(7), 32- 36. Smith, L. W., & Fay, T. (1940). Observations on human beings with cancer maintained at reduced temperatures of 75-90* Fahrenheit. American Journal of Clinical Pathology, 10, 1-11. Valley Hospital, (2009). [ED therapeutic hypothermia nursing pathway]. Unpublished raw data.