A Case Report of Therapeutic Hypothermia in the Postoperative Cardiac Arrest of a Noncardiac Surgical Patient

Abstract

Therapeutic hypothermia (TH) has been used to decrease neurological morbidity in comatose patients who have suffered out-of-hospital cardiac arrest. In the modern TH era, there are no studies evaluating the use of TH in postoperative cardiac arrest patients. Generalization of the use of TH to include postoperative cardiac arrest patients has not been systematically studied or reported. This is possibly secondary to potential complications specific to this population pool. Hypothermia can induce bleeding diathesis, delay wound healing, and increase the risk of wound infections. A recent case series examining complications after the use of TH in three postcardiac surgery cardiac arrest patients revealed no significant bleeding, electrolyte disturbances, or dysrhythmias, with the benefit of good neurological outcomes. We present the first case report of TH use in the postoperative cardiac arrest of a noncardiac surgical patient in the modern TH era. This report is of a 75-year-old woman who underwent elective colorectal resection complicated by postoperative cardiac arrest. She was successfully treated with TH. To our knowledge, this is the first report of a successful application of TH in the cardiac arrest of a postoperative noncardiac surgical patient. The complications that could have been attributed to TH were hypokalemia, hypomagnesaemia, sinus bradycardia, and ventilator-acquired pneumonia. In this case, TH was not associated with postoperative bleeding, delayed wound healing, anastomotic dehiscence, or wound infection. We hope that our report sparks future studies investigating TH in postoperative patients.

Introduction

In 2002, the Hypothermia after Cardiac Arrest Study Group determined that therapeutic mild hypothermia increased the rate of a favorable neurologic outcome and reduced mortality in patients who had been successfully resuscitated after cardiac arrest caused by ventricular fibrillation (VF) (The Hypothermia after Cardiac Arrest Study Group, 2002). In the same year, another randomized controlled trial affirmed the neurological benefit in comatose survivors of out-of-hospital cardiac arrest patients treated with hypothermia (Bernard et al., 2002). As a result of these studies, the Advanced Life Support Task Force of the International Liaison Committee on Resuscitation (ILCOR) recommends the use of therapeutic hypothermia (TH) in unconscious adult patients with return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest in which the initial rhythm was VF (Nolan et al., 2003). In this case, patients can be cooled to 32–34°C for 12–24 hours. However, there are no randomized controlled trials evaluating the use of TH in postoperative cardiac arrest patients.

Widespread, systemic generalization of the use of TH to include postoperative cardiac arrest patients who underwent a noncardiac procedure has not been reported in the modern TH era. Indeed, there may be potential complications of TH specific to this population pool. Hypothermia can induce bleeding diathesis, increase bleeding time through its effects on platelets and the clotting cascade, and induce arrhythmias and electrolyte dysfunction (Polderman and Ingeborg, 2009). In addition, hypothermia may delay wound healing and increase the risk of wound infections (Kurz et al., 1996). A recent case series examining complications after the use of TH in three post–cardiac surgery cardiac arrest patients revealed no significant bleeding, electrolyte disturbances, or dysrhythmias, with the benefit of good neurological outcomes (Rinehart et al., 2012). Encouraged by these positive results, we advocate that further studies are needed to investigate the use of TH for cardiac arrest in noncardiac surgical patients. We present such a case in this report.

Case Presentation

A 75-year-old Caucasian woman was referred to the surgeon's office to evaluate three distinct masses within the pelvis found on computed tomography. She had a history of gastrointestinal stromal tumors treated 4 years before presentation, with total abdominal hysterectomy, left salpingo-oophorectomy, and resection of pericolonic masses. Given the recurrent tumor burden, she was admitted to our hospital in 2012 for resection of the masses. The patient had a medical history of atrial fibrillation, hypertension, and smoking. She had a preoperative work-up including routine lab work, and she was cleared for surgical treatment. As planned, she underwent resection of the pelvic masses, including recto-sigmoid resection with a primary anastomosis. The procedure lasted approximately 4 hours with an estimated blood loss of 1 L and a urine output of 500 cc during the procedure. She received a total of 5 L of normal saline and 1 unit of packed red blood cells (RBC) intraoperatively and was planned to receive 2 units of RBC postoperatively. Table 1 demonstrates the intravenous sedative and muscle relaxant medications received intraoperatively. In light of the lengthy procedure, she remained intubated in the postanesthesia care unit (PACU) with Glasgow Coma Scale (GCS) of 11T. She was eventually put on a T-piece trial to assess readiness for extubation.

Table 1.

The Intravenous Sedative and Muscle Relaxant Received Intraoperatively Before the Cardiac Arrest

Medication	Dose	Time of administration
Etomidate	20 mg	12:38
Sufentanil	250 mg	12:38–15:00
Rocuronium	50 and 20 mg	12:38 and 15:10
Morphine	5 mg	17:10

Immediately after endotracheal suctioning, she became cyanotic and bradycardic. She was given atropine for symptomatic bradycardia. The patient then went into cardiac arrest with a presenting rhythm of VF. Advanced cardiac life support was performed, including two attempts at defibrillation with ROSC after 15 minutes. After 62 minutes of ROSC, the patient suffered a second cardiac arrest with a successful ROSC after 5 minutes. She was found to have bilateral pneumothoraces on chest X-ray postchest compressions, which required bilateral chest tube placement. She received a total of two units packed RBCs in the recovery room as planned before cardiac arrest.

TH was initiated 40 minutes after the first ROSC. The patient's GCS during the time of cooling remained 3. Cooling was initiated with ice packs placed in the groin, axilla, and posterior neck. Cold saline was infused via central line 1 hour after application of the ice packs. The definitive method of cooling was the Arctic Sun device (Medivance Inc., Louisville, CO). This was started 4 hours and 50 minutes after the first ROSC. A target temperature of 34°C was achieved within 7 hours of initiation of cooling and was continued to maintain a temperature of 33–34°C for a total of 24 hours. A summary of the timeline of the significant events surrounding the arrest and perihypothermia period is included in Table 2. She was monitored on VEEG with no evidence of seizures. Electrolyte abnormalities were detected after the application of TH. These included hypokalemia, hypocalcemia, and hypomagnesemia. EKG revealed flattened T waves and prolonged QTc (543 ms) with no life-threatening arrhythmia. The lowest heart rate recorded was 48 bpm, which was probably secondary to TH. No electrolyte abnormality or arrhythmia was noted during the rewarming period. Table 3 demonstrates the recorded electrolyte abnormalities in the post-TH period and the given replacements. After TH the patient's coagulation profile was within normal limits: prothromin time, 12.9 seconds; partial thromboplastin time, 31.9 seconds.

Table 2.

The Timeline of Significant Events Pre- and Postcardiac Arrest and Therapeutic Hypothermia

Time	Significant event
POD0
17:21	Surgery end time
17:45	Patient admitted to postanesthesia care unit with GCS 11T (on T piece endotracheal tube)
18:50	Bradycardia
18:54	First cardiac arrest
19:08	Return of spontaneous circulation
19:48	Ice packs applied
20:10	Second cardiac arrest
20:15	Return of spontaneous circulation
20:18	Left pneumothorax discovered
20:45	Left chest tube was placed.
20:50	Infusion of cold saline was started.
21:15	Body temperature 35°C
21:40	Patient was transferred to ICU.
21:50	Arctic Sun device was applied.
22:00	Body temperature 35.2°C
23:05	Right chest tube was placed for right pneumothorax.
POD1
3:00 AM	Targeted temperature of 33°C was reached.

GCS, Glasgow Coma Scale; POD, postoperative day.

Table 3.

Summary of the Measured Serum Electrolytes and the Given Replacement Postcardiac Arrest and Therapeutic Hypothermia

	Serum Na (meq/dL)	Serum K (meq/dL)	Serum Mg (meq/dL)	Serum Cl (meq/dL)	Serum Ca (mg/dL)	Albumin (gm/dL)
POD0
18:11	139	3.4	1.7	109	6.6
21:03	140	3.2	1.6	111	7.9
23:36	142	3.0	1.4	117	6.4
	Replacement given on POD 0 was 40 meq KCl, 2 g MgSO₄, and 1 g of Ca gluconate.
POD1
04:43	145	2.5	1	127	4.5	1.4
17:22	141	3.5	1.9	113	7.0	2.3
21:30	141	2.3	1.5	119	5.4	1.7
	Replacement given on POD 1 was 80 meq KCl, 2 g MgSO₄, and 1 g Ca gluconate.
POD2
05:01	144	3.8	2.4	116	7.0	2.2
	Replacement given on POD 2 was 20 meq KCl.
POD3
04:54	144	3.2	1.9	111	6.8	2.2
18:32	145	4.5	2.5	113	6.9

On postoperative day (POD) 5, she spiked a fever of 100.6°F. Chest X-ray revealed further interval progression of bilateral patchy opacities. Deep tracheal aspirate revealed pseudomonas, and the patient was treated for ventilator-acquired pneumonia with cefepime and gentamicin. Her wound had healed well without dehiscence or infection. The patient was unable to be weaned from mechanical ventilation, and on POD 15 she underwent a tracheostomy. On POD 44 she was transferred, with a GCS score of 12, to a ventilator unit. After failing multiple feeding trials secondary to dysphagia on POD 57, a percutaneous endoscopic gastric tube was placed. On POD 64 she was discharged to a long-term acute care facility. While her GCS remained 3 for the first postoperative week, she started to improve and her Glasgow-Pittsburgh Cerebral Performance Category (CPC) (Cummins et al., 1991) upon discharge was a 3. Moreover, she was able to communicate coherently to her family and the hospital staff. At the 6-month follow-up visit, the patient achieved a CPC of 1, a successful decannulation of tracheostomy, and independent daily activities performance.

Discussion

TH can have many complications. A major feared complication of TH in surgical patients is coagulopathy. However, the application of TH in our noncardiac surgical patient was not associated with bleeding or coagulopathy. This was true in spite of the fact that we encountered significant intraoperative bleeding and performed an extensive pelvic dissection. While platelet dysfunction can occur with temperatures less than 35°C, clotting factors are not disrupted until temperature drops below 33°C [4]. Regardless of that, our patient, who was cooled from 33°C to 34°C, did not bleed significantly, even though she underwent a surgical procedure that was at high risk for bleeding. This may increase the appeal for TH even in patients undergoing high-risk surgical procedures.

Our findings have been supported by additional previous studies. In a case series by Rinehart et al. (2012), there was no significant bleeding or coagulopathy when TH was used for perioperative cardiac arrest in cardiac surgical patients. In addition, a prospective comparative study investigating the use of TH for cardiac arrest in myocardial infarction patients showed no difference in the rate of bleeding between TH and non-TH groups (Schefold et al., 2009). Furthermore, one of the landmark studies for the use of TH in out of hospital cardiac arrest patients that included 273 patients revealed no difference in bleeding risk between TH and non-TH groups (The Hypothermia after Cardiac Arrest Study Group, 2002). Another randomized controlled trial investigating TH use in 82 traumatic brain injury patients reported no difference in prothrombin time or platelet counts between TH and non-TH groups (Marion et al., 1997). Of note, this study had 24% and 74% of their included patients suffer abdominal and thoracic injuries, respectively (Marion et al., 1997).

Our patient did suffer from hypokalemia, hypomagnesaemia, pneumonia, and bradycardia. However, these complications are not limited to surgical patients. A review of 986 patients who underwent TH for out-of-hospital cardiac arrest found the most common complication of TH to be pneumonia (41%). Also of note, hypokalemia and hypomagnesaemia were each present 18% of the time and bradycardia was present 13% of the time (Nielsen et al., 2009). Therefore, our patient experienced similar side effects as the traditional patient population that has been approved by ILCOR to receive TH. In addition, the electrolyte abnormalities experienced by our patient did not result in any life-threatening arrhythmias.

The decision to induce TH was made at an interdepartmental level with coordination between the surgical and medical ICU directors. While the hospital protocol for TH did not include surgical patients, this patient fulfilled the basic indications for TH, including a VF arrest and the ROSC with a resultant GCS of 3. This was an unprecedented course of action. As such, our standard approach (brief utilization of ice packs and intravenous cold saline with immediate application of Arctic Sun device) was not used. To expedite the cooling within the recommended 3-hour window, ice packs and cold saline were used in the PACU before setting up the Arctic Sun device. This was a temporizing measure before transfer to the cardiac care unit, where the Arctic Sun device is usually managed by staff trained in TH monitoring.

It has been previously reported that an undesired decrease in normal temperature by 2°C triples the risk of wound infection (Kurz et al., 1996). This side effect was not noted in our patient. Clearly, additional inquiry would be required to identify the incidence of wound infection and delayed healing in patients who undergo controlled postoperative hypothermia. While the most dreaded complication of hypothermia after surgery would be death, a recent retrospective study of 23,165 patients who experienced spontaneous hypothermia after major elective noncardiac surgery revealed no increased hospital mortality attributable to hypothermia, although the lowest temperature recorded was 34.8°C (Karalapillai et al., 2013). Regardless of the minimum temperature recorded, this study and our case report provide hope for the use of TH for patients who undergo cardiac arrest after major noncardiac surgery.

Our patient did not experience major complications of TH that would be specific to surgical patients. This, combined with the fact that the patient was discharged with a CPC of 3, provides hope to the generalization of ILCOR's recommendations on the use of TH to patients who suffer from cardiac arrest after noncardiac surgery. Our report should spark interest into conducting prospective studies on the effects of TH on future postoperative cardiac arrest patients.

Conclusions

We have reported the case of a 75-year-old woman who presented for elective colon resection and underwent postoperative cardiac arrest twice. She was successfully treated with TH, with a CPC of 1 at the 6-month follow-up visit. To our knowledge, this is the first report of a successful application of TH in the cardiac arrest of a postoperative noncardiac surgical patient. The complications that could have been attributed to TH were hypokalemia, hypomagnesaemia, sinus bradycardia, and ventilator acquired pneumonia. In our case, TH was not associated with any evidence of postoperative bleeding, delayed wound healing, anastomotic dehiscence, or wound infection. We hope that our report sparks future studies investigating TH in postoperative patients.

Footnotes

Author Disclosure Statement

No competing financial interests exist.

References

Bernard

, Gray

, et al. Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. N Engl J Med, 2002; 3466:557–563.

Cummins

, Chamberlain

, et al. Recommended guidelines for uniform reporting of data from out-of-hospital cardiac arrest: The Utstein style. Circulation, 1991; 84:960–975.

The Hypothermia after Cardiac Arrest Study Group. Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest. N Engl J Med, 2002; 346:549–556.

Karalapillai

, Story

, et al. Postoperative hypothermia and patient outcomes after major elective non cardiac surgery. Anaesthesia, 2013; 68:605–611.

Kurz

, Sessler

, Lernhardt

. Perioperative normothermia to reduce the incidence of surgical-wound infection and shorten hospitalization. N Engl J Med, 1996; 334:1209–1215.

Marion

, Penrod

, et al. Treatment of traumatic brain injury with moderate hypothermia. N Engl J Med, 1997; 336:540–546.

Nielsen

, Hovdenes

, et al. Outcome, timing and adverse events in therapeutic hypothermia after out-of-hospital cardiac arrest. Acta Anaesthesiol Scand, 2009; 53:926–934.

Nolan

, Mortley

, et al. Therapeutic hypothermia after cardiac arrest: An advisory statement by the Advanced Life Support Task Force of the International Liaison Committee on Resuscitation. Circulation, 2003; 108:118–121.

Polderman

, Ingeborg

. Therapeutic hypothermia and controlled normothermia in the intensive care unit: Practical considerations, side effects, and cooling methods. Crit Care Med, 2009; 37:1101–1120.

10.

Rinehart

, Merkel

, et al. Therapeutic hypothermia after perioperative cardiac arrest in cardiac surgical patients. ICU Director, 2012; 3:271–278.

11.

Schefold

, Storm

, et al. Mild therapeutic hypothermia after cardiac arrest and the risk of bleeding in patients with acute myocardial infarction. Int J Cardiol, 2009; 132:387–391.