The Journal

of Emergency

Medicine,

Vol 10, pp 427-433,

Printed in the USA . Copyright

1992

0 1992 Pergarnon

Press Ltd.

ACCIDENTAL HYPOTHERMIA WITH CARDIAC ARREST: RECOVERY FOLLOWING REWARMING BY CARDIOPULMONARY BYPASS Edward Bolgiano, “Division

of Emergency Reprint

Address:

MD,

Medicine, Edward

* Leon Sykes, tm,t Robert A. Barish, and Brian Eastridge, MDt tDivision

* Roderick Zickler, MD,t

of General Surgery, Department of Surgery, University 22 South Greene Street, Baltimore, MD B. Bolgiano, MD, FACEP, 419 West Redwood Street, Suite 280,

q Abstract-A 22-year-old man eventually had a good neurologic recovery following prolonged coma after extracorporeal rewarming from profound hypothermia (24°C) due to exposure. The patient was in full arrest for 60 minutes prior to institution of cardiopulmonary bypass (CPB). Total bypass time was 50 minutes. Cardiopulmonary bypass is the current rewarming method of choice for severe hypothermia associated with a persistent nonperfusing cardiac rhythm. CPB provides the most rapid core rewarming with the additional benefit of circulatory support during the period of cardiac instability. 0 Keywords-hypothermia; real; rewarming

MD,

of Maryland Baltimore,

Medical

System,

MD 21201

pothermia and the clinical presentation (2). An empiric hypothermia outcome score (HOS) has been developed by Danzl and colleagues (3) using data compiled by the Hypothermia Study Group (4) to permit future evaluation and comparison of different therapeutic modalities. Profound or severe hypothermia, defined as body core temperature below 28 OC, has an estimated mortality of 30% to 80% (5). Aggressive therapeutic intervention is required because of the cardiovascular instability that occurs below this temperature. Ventricular fibrillation may be spontaneous below 28OC, and asystole is common as the temperature is further lowered. Cardiopulmonary bypass (CPB) has been advocated by many authors (5-22) as the rewarming method of choice for severe hypothermia (T < 28 “C) associated with a persistent nonperfusing cardiac rhythm (asystole or ventricular fibrillation). Appropriate prehospital and emergency department management, including indications for institution of CPB, has been previously summarized by Zell (23) in a resuscitation protocol for severe hypothermia (Figure 1). Cardiopulmonary bypass is an attractive technique because effective perfusion is reinstituted regardless of the cardiac rhythm and rewarming occurs more rapidly than with conventional ACR techniques such as peritoneal lavage and airway rewarming (14). Femoral cannulation, which now may be established by the percutaneous route (5) either in the emergency department or in the operating room, greatly facili-

arrest; bypass; extracorpo-

INTRODUCTION

Hypothermia is defined as body core temperature below 35OC (95OF). A wide range of clinical presentations are possible depending upon the etiology, severity of hypothermia, and associated medical conditions of the patient. Prospective controlled studies of treatment and outcome do not exist in the hypothermia literature because most individual centers do not treat a sufficient quantity of similar patients (l), and treatment continues to be controversial. Various treatment options, including passive external rewarming (PER), active external rewarming (AER), and active core rewarming (ACR) techniques (Table 1) may be appropriate depending on the severity of hy-

= Clinical Communlcatlons, focusing primarily on adult emergencies, is coordinated by Ron Walls, w ver General Hospital, Vancouver, BC, Canada. RECEIVED: 17 January 1991; FINAL SUBMISSION RECEIVED: 30 May 1991; 07364679192 ACCEPTED: 17 June 1991 427

MD,

of Vancou-

$5.00 + .OO

428

E. Bolgiano,

Table 1. Rewarming

Methods

Passive External (PER) Removal from cold environment Insulation Active External (AER) Warm water immersion Heating blankets Plumbed garments Heated objects (water bottles, etc.) Radiant heat Active Core (ACR) Inhalation rewarming Warmed IV fluids GI tract irrigation Bladder irrigation Peritoneal dialysis Hemodialysis Radiowave/Microwave Mediastinal lavage Continuous thoracostomy lavage (two-chest-tube) Extracorporeal rewarming (CPB)

tates rapid institution of CPB and may permit its more widespread use. We present a case of a profoundly hypothermic patient successfully resuscitated using CPB and we discuss the technical aspects of emergency femoralfemoral CPB.

L. Sykes, R. A. Barish, R. Zickler, 8. Eastridge

skilled in the procedure of intubation.) Total transport time was 10 minutes. On arrival the patient was orally intubated and cardiopulmonary resuscitation (CPR) was continued. Physical examination on arrival revealed a well developed, unresponsive black man in his early 20s. His clothing was clean and he was well groomed. There was no alcohol odor. His initial temperature was 24OC (74OF), obtained with a rectal probe. Asystole was present on cardiac monitoring. Pupils were 6 mm size, midposition, and unreactive to light. There was a 2-cm superficial laceration above his right eyebrow but there was no other evidence of head trauma. There was no response to deep pain (Glasgow Coma Scale score of 3). Extremities were slightly rigid on passive flexion and extension, and his skin was cold and dry. The remainder of the physical examination was unremarkable. ACR with warm (37OC) humidified oxygen via the endotracheal tube, warmed (4OOC) isotonic intravenous fluids, and peritoneal lavage (40°C) were begun as temporizing measures while arrangements were made in the operating room for CPB. In preparation for CPB, the left femoral artery and vein were surgically exposed in the emergency department. Active external rewarming techniques were withheld.

CASE REPORT

A 22-year-old black man was found lying in a parking lot in West Baltimore at 0800 on 18 December 1989. Overnight low temperature in the area was 15 OF. The patient was dressed in inappropriately lightweight clothing that was frozen. EMTs at the scene found the patient lying motionless and moaning. Vital signs were pulse 50 beats/min (irregular), blood pressure unobtainable, and respirations 6 breaths/min and shallow. Oxygen was applied at 10 L/min via nonrebreather mask. Intravenous access was achieved with some difficulty in the forearm (the patient’s upper extremities were rigid and the elbows were very difficult to extend). Fifty grams of 50% dextrose and 2 mg of naloxone were administered intravenously without response. Telemetry consultation was obtained with the University of Maryland Emergency Department and an electrocardiographic (ECG) strip was obtained (Figure 2). Following loading into the ambulance, the patient’s rhythm degenerated into ventricular fibrillation. The patient was defibrillated twice, and epinephrine and lidocaine were administered en route to the hospital with no change in the patient’s rhythm. (The patient was not intubated in the field only because the prehospital providers involved were not

Figure 1. Emaq@ncy cbparWmt posure hypot@dapted from

of eewre

ex-

429

Extracorporeal Rewarming

Figure 2. Telemetry

ECG strip obtained

prior to arrest of the patient in the field. Note prominent

Initial laboratory values were as follows: arterial blood gas (uncorrected for temperature) pH 7.18, pOZ 423 torr, pCOZ 28 torr; sodium 145 mEq/L, potassium 5.5 mEq/L, chloride 111 mEq/L, CO2 content 15 mEq/L, glucose 29 mg/dL (following prehospita1 intravenous dextrose), BUN 13 mg/dL, creatinine 0.8 mg/dL; WBC 18.6/mm3, hemoglobin 11.8 g/dL, hematocrit 36.5%, platelets 247 thousand/pL. Toxicology screen was positive for cocaine, quinine, and PCP. Blood ethanol was 44 mg/dL. Other laboratory values (normal ranges in parentheses) at the time of presentation included: PT 11.8 seconds (10.2-l 1.7), PTT 29 seconds (22-3 l), fibrinogen 121 mg/dL (160-360), albumin 2.9 g/dL (3.55.0), calcium 6.8 mg/dL (9.1-10.6), alkaline phosphatase 81 IU/L (38-126), AST 1647 IU/L (lo-50), ALT 625 IU/L (7-56), LDH 7121 IU/L (313-618), total bilirubin 0.8 mg/dL (0.2-l.O), CK total 5077 IU/L (60-320), CK-MB 25 IU/L, amylase 78 UL (30-l 10). The patient received additional intravenous dextrose and was transported to the operating room. The femoral venous cannula and the femoral arterial cannula were introduced and, after systemic heparinization (5,000 units) of the patient, flow was begun 50 minutes after arrival of the patient in the emergency department. Due to the patient’s small femoral vessel caliber, the usual 5 liters per minute of flow was not achievable; the maximum flow obtained was approximately 3.5 liters per minute. The patient’s core temperature rose from 26OC on reaching the operating room to 32OC before coming off CPB (Figure 3). When the patient reached 30°C, his cardiac rhythm changed from asystole to coarse ventricular fibrillation. He was able to be externally defibrillated following intravenous epinephrine and lidocaine, and maintained a sinus rhythm with a rate of 100 beats/min and a systolic blood pressure of 110 torr on his own after discontinuation of CPB flow.

J or Osborn waves.

After removal of the femoral venous catheter, the vein was repaired with running #5-O prolene suture. Following this, the remainder of the volume in the pump was returned to the patient through the femoral artery. The femoral arterial catheter was then removed and the femoral artery was repaired. The patient received a total of 3.5 liters of crystalloid and 3 units of packed red blood cells while on bypass. Following transport to the intensive care unit, the patient’s blood pressure remained stable without the use of pressor agents, and no cardiac dysrhythmia developed. His temperature stabilized in the normal

36

” & L

30

E

28

Figure 3. Course and treatment of 22-year-old man with severe hypothermia due to exposure. VF indicates ventricular fibrillation; AF, atrial flbrilfatlon; NSR, normal sinus rhythm; CPR, cardiopulmonary reauscltation; CM, conventkwml core rewarming; ECR, extracorporeal rewarming. Solid clrcles Indicate rectal temperature.

430

E. Bolgiano,

range. Although during the initial hours following CPB, the patient’s mental status improved somewhat and he was intermittently responsive to stimuli and simple verbal commands, this did not persist and he became progressively vegetative, at that time thought most likely due to anoxic encephalopathy. Head computed tomography (CT scan) revealed a minor cerebral contusion and an electroencephalogram was consistent with diffuse encephalopathy. The patient developed Adult Respiratory Distress Syndrome (ARDS) on the 5th day of hospitalization, which resolved by the 10th day, and although he eventually required tracheostomy, ventilatory support was discontinued. A percutaneous endoscopic gastrostomy was performed for nutritional support. He remained responsive only to pain for the remainder of his hospitalization (total 63 days) and was transferred to a nursing home for total supportive care. While at the nursing home, the patient showed progressive neurologic improvement. The tracheostomy and gastrostomy were discontinued, and the patient was sent home to live with his sister. At one year following his initial resuscitation, the patient has a normal speech pattern, is fully ambulatory, and is able to perform all activities of daily living independently. He has a mild decrease in his cognitive abilities, but his remote memory is intact and he is able to enjoy reading, listening to the radio, and watching television. He is able to converse in a normal manner and responds appropriately to all questions. The pa-

tient suffers some peripheral nerve damage in his upper extremities, for which he is receiving physical therapy, but his neurologic examination is otherwise normal.

L. Sykes, R. A. Barish, R. Zickler, B. Eastridge

TECHNICAL ASPECTS OF FEMORAL-FEMORAL CPB Femoral-femoral CPB circuits consist of arterial and venous cannulas, tubing, a mechanical vortex pump, membrane or bubble oxygenator, and a heat exchanger. The venous cannula is a 16-30 French tube passed via the femoral vein to the level of the junction of the right atrium and inferior vena cava. The arterial cannula is a shorter, larger diameter 16-20 French tube passed via the femoral artery to the level of the abdominal aortic bifurcation (Figure 4). The catheters may be introduced by cutdown and surgical exposure of the femoral vessels (as in our case report) or may be introduced percutaneously over a guidewire using a series of stepped dilators (5). Newer catheters and tubing have nonthrombogenic blood contact surfaces. The centrifugal, disposable vortex pump head is attached to the portable bypass machine, which in some systems may also contain the heat exchanger. Most pumps are designed to operate at flow rates in the range of 1 to 7 liters per minute, thereby potentially approximating normal cardiac output. The temperature at which the heat exchanger perfusate is maintained during rewarming has in pre-

oxygenator

-Venous

Line

Figure 4. Schemetic illuetratlon of femoral-Wfemoml byfwee eyetem. Note location of tip of venous cannula et junctkw of right stttum (RA) and infertor vene cava (WC). In actuel uee, the oxygenator and pump are attwhed to a portebte bypew machlne. The heat exchanger may be either an Integml part of the portable machine or may be a eeparate element. (Dram adapted from reference 5)

Extracorporeal

Rewarming

431

vious cases been reported as 5 OC gradient above core temperature (6), 10°C above core (19), normal body temperature (7,9,11), or has not been explicitly reported. In our case we maintained a temperature gradient of 5OC between the perfusate and the patient’s core temperature. Although there may be some theoretical problems with increased bubbling in the system if high perfusate-core gradients are used, this question has not been adequately addressed in the literature.

40 cases have been presented in the literature (English language) describing use of CPB in the treatment of victims of severe accidental hypothermia (Table 2). In this collection of independent reports, the survival rate is 66% (25/38). The Mt. Hood climbing disaster of May 1986 is responsible for the largest series to date, in which 10 patients were treated by CPB with a survival rate of 20% (18). The mean core temperature of 7 of the 8 nonsurvivors in this series was 7OC, far lower than is commonly found clinically and lower than any other group in the literature to date (Table 2). If these 7 extremely cold patients from the Mt. Hood disaster are excluded, the overall survival rate for reported cases of hypothermia resuscitation using CPB increases from 66% to 81% (25/31). The actual survival rate is probably lower than this, how-

DISCUSSION In 1967 Kugelberg first reported the use of cardiopulmonary bypass (CPB) to rewarm a patient with severe accidental hypothermia (6). Since then, almost Table 2. Summary of Cases of Profound Investigator (ref)

Date

Kugelberg et al (6) Davies et al (7) Fell et al (6) Towne et al (9) Wickstrom et al (10)

1967 1967 1966 1972 1972-73

Truscott et al (11) Dorsey (12) Althaus et al (13)

1973 1960 1962

Splittgerber et al (14)

1980-86

Nesemann et al (15) Thorpe et al (16)

1983 1986

Maresca et al (17)

1987

Hauty et al (16)

1987

Bolte et al (19) Cohen et al (20) Laub et al (5) Husby et al (21) Kelly et al (22) Current case

1988 1988 1989 1990 1990 1989

Hypothermia AgelSex 59 M 82 F 42 F 58 M 65 F 45 F 64 M 23 F 60 M 42 M 24 F 40 M 55 M ? age M 54 M 40 M 40 M 30 M 16M ? age M 31 F 25 F 15F 15M 15M 15F 15F 15F 40 F 15M 41 M 15M 2F 32 M 60 F 51 M 2M 22 M

Treated with Cardiopulmonary Core temperature 21 oc 34% 22% 25 25 20 24 22 26

19 24 22 21 21 21 23 24 22 22 21 25 24 23 22 7 8 7 6 7 12 20 3 22 28 26 27 15 24

“C OC oc =‘C oc OC oc “C oc oc oc 72 OC ‘=C oc oc -2 OC “C “C oc OC “C OC OC oc “C “C oc % -2 -2 “C “C -2

Bypass

Type of bypass

Survival

femoral-femoral femoral-femoral atrial-aortic femoral-femoral femoral-femoral femoral-femoral femoral-femoral femoral-femoral femoral-femoral femoral-femoral femoral-femoral femoral-femoral

l/l l/l l/l l/l 213

femoral-femoral femoral-femoral femoral-femoral femoral-femoral atrial-aortic femoral-femoral atrial-aortic femoral-femoral femoral-femoral atrial-aortic atrial-aortic (attempted) atrial-aortic atrial-aortic (attempted) femoral-femoral femoral-femoral femoral-femoral femoral-femoral femoral-femoral femoral-femoral atrial-aortic femoral-femoral

011 212

l/l l/l 212 316

212 2110

l/l l/l 111 111 l/l 111

432

E. Bolgiano,

Table 3. Contraindications

and Complications

of CPB

Contraindications Anticoagulation risk (multiple trauma)* Obviously lethal injuries Documented DNR Failure to obtain venous return Clotted atrial blood Complications Air Embolism Pulmonary edema Hemolysis Coagulation abnormalities, including DIC Damage to femoral vessels Frostbite exacerbation *Full systemic heparinization not required with newer heparincoated tubing and oxygenators.

ever, since most cases of poor outcome following resuscitation with CPB are probably not reported, whereas cases with an excellent outcome are readily published (24). CPB has three major advantages over other ACR techniques: 1) CPB provides the most rapid restoration of normothermia, rewarming of more than 4 times the rate of conventional ACR techniques such as peritoneal lavage and airway rewarming; 2) perfusion with oxygenated blood is maintained regardless of cardiac rhythm or pulmonary status; and 3) the high blood viscosity associated with severe hypothermia is reduced. The disadvantages of CPB include the lack of gen-

L. Sykes, R. A. Barish, R. Zickler, B. Eastridge

eral availability and the risks of heparinization. Newer heparin-coated tubing and oxygenators circumvent the need for full systemic heparinization. Contraindications and reported complications of CPB are summarized in Table 3. Femoral-femoral cardiopulmonary bypass appears to be the treatment of choice for profound hypothermia. Although not all centers are capable of CPB, regionalization of care for the profoundly hypothermic patient (similar to systems for major trauma patients) is a reasonable approach (19). In those cases where timely transport to a regional CPB center is not feasible, other ACR techniques should be used. Of these, recent reports of continuous thoracostomy lavage using a two-chest-tube system appear to be especially promising. Continuous thoracostomy lavage using a two-chest-tube system offers several advantages over CPB: universal availability, lack of requirements for specialized equipment and personnel, and no systemic heparinization requirement. Continuous thoracostomy lavage has been shown to provide rapid central rewarming in animal studies (25,26). Although experience with continuous thoracostomy lavage in humans is limited to anecdotal reports (27,28), a recent report (28) of its successful use in the resuscitation of a severely hypothermic patient (23.7OC) in cardiopulmonary arrest (asystole) makes this a procedure that deserves consideration in situations in which CPB is not available.

REFERENCES 1. Danzl DF, Pozos RS, Auerbach PS, et al. Multicenter hypothermia survey. Ann Emerg Med. 1987;16:1042-55. 2. DanzJ DF. Accidental hypothermia. In Rosen P, ed. Emergency medicine: concepts and clinical practice. 2nd ed. St. Louis: CV Mosby; 1988. 3. Danzl DF, Hedges JR, Pozos RS, et al. Hypothermia outcome score: development and implications. Crit Care Med. 1989;17: 227-3 1. 4. Danzl DF, Pozos RS, Auerbach PS, et al. Hypothermia study group: multicenter hypothermia survey. Ann Emerg Med. 1987;16:1042. 5. Laub GW, Banaszak D, Kupperschmid J, Magovern GJ, Young JC. Percutaneous cardiopulmonary bypass for the treatment of hypothermic circulatory collapse. Ann Thorac Surg. 1989;47:608-11. 6. Kugelberg J, Schuller H, Berg B, Kallum B. Treatment of accidental hvnothermia. Stand J Thor Cardiovasc Surg. 1967; 1:142-6. _7. Davies DM, Millar EJ, Miller IA. Accidental hypothermia treated by extracorporeal blood-warming. Lancet. 1967;l: 1036-7. 8. Fell RH, Gunning AJ, Bardhan KD, Triger DR. Severe hypothermia as a result of barbiturate overdose complicated by cardiac arrest. Lancet. 1968;1:392-4. 9. Towne WD, Geiss WP, Yanes HO, Rahimtoola SH. Intractable ventricular fibrillation associated with profound accidental

hypothermia- successful treatment with partial cardiopulmonary bypass. New Engl J Med. 1972;287:1135-6. 10. Wickstrom P, Ruiz E, Lilja GP, Hinterkopf JP, Haglin JJ. Accidental hypothermia: core rewarming with partial bypass. Am J Surg. 1976;131:622-5. 11. Truscott DG, Firor WB, Clein LJ. Accidental profound hypothermia. Arch Surg. 1973;106:216-18. 12. Dorsey JS. Venoarterial bypass in hypothermia [letter]. JAMA. 1980;244:1900. 13. Althaus U, Aeberhard P, Schupbach P, Nachbur BH, Muhlemann W. Management of profound accidental hypothermia with cardiorespiratory arrest. Ann Surg. 1982;195:492-5. 14. Splittgerber FH, Talbert JG, Sweezer WP, Wilson RF. Partial cardiopulmonary bypass for core rewarming in profound accidentrdhypothermia.Am Surg. 1986;52:407-12.~ 15. Nesemann ME. Busch HM. Gundersen AL. Gundersen AE. Newcomer KL.‘Asystolic cardiac arrest in hypothermia. Wisd Med J. 1983;82:19-20. 16. Thorpe AD, White DE. Accidental hypothermia treated by cardiopulmonary bypass. ICPS Digest. 1986; 1(1):3-8. 17. Maresca L, Vasko JS. Treatment of hypothermia by extracorporeal circulation and internal rewarming. J Trauma. 1987; 27(1):89-90. 18. Hauty MG, Esrig BC, Hill JG, Long WB. Prognostic factors in severe accidental hypothermia: experience from Mt. Hood tragedy. J Trauma. 1987;27:1107-12.

Extracorporeal Rewarming 19. Bolte RG, Black PC, Bowers RS, Thorne JK, Corneli HM. The use of extracorporeal rewarming in a child submerged for 66 minutes. JAMA. 1988;260:377-9. 20. Cohen DJ, Cline JR, Lepinski SM, Bowman HM, Ireland K. Resuscitation of the hypothermic patient. Am J Emerg Med. 1988;6:475-8. 21. Husby P, Andersen KS, Owen-Falkenberg A, Steien E, Solheim J. Accidental hypothermia with cardiac arrest: complete recovery after prolonged resuscitation and rewarming by extracorporeal circulation. Intensive Care Med. 1990,16:69-72. 22. Kelly KJ, Glaeser P, Rice TB, Wendelberger KJ. Profound accidental hypothermia and freeze injury of the extremities in a child. Crit Care Med. 1990;18:679-80. 23. Zell SC, Kurtz KJ. Severe exposure hypothermia: a resuscitation protocol. Ann Emerg Med. 1985;14:339-45.

433 24. Orlowski JP. Drowning, near-drowning, and ice-water drowning [editorial]. JAMA. 1988;260:390-1. 25. Brunnette DD, Sterner S, Robinson EP, Ruiz E. Comparison of gastric lavage and thoracic cavity lavage in the treatment of severe hypothermia in dogs. Ann Emerg Med. 1987; 16: 1222-6. 26. Barr GL, Halvorsen LO, Donovan AJ. Correction of hypothermia by continuous pleural perfusion. Surgery. 1988;103: 553-7. 27. Baxter BT, Moore EE, McCroskey BL, Moore FA. Chest tube irrigation for post injury hypothermia. Ann Emerg Med. 1988; 17:999-looo. 28. Iversen RJ, Atkin SH, Jaker MA, Quadrel MA, Tortella BJ, Odom JW. Successful CPR in a severely hypothermic patient using continuous thoracostomy lavage. Ann Emerg Med. 1990;19:1335-7.