Tuesday, March 23, 2021

Penetrating Trauma and Massive Transfusion Case File

Posted By: Medical Group - 3/23/2021 Post Author : Medical Group Post Date : Tuesday, March 23, 2021 Post Time : 3/23/2021
Penetrating Trauma and Massive Transfusion Case File
Lydia Conlay, MD, PhD, MBA, Julia Pollock, MD, Mary Ann Vann, MD, Sheela Pai, MD, Eugene C. Toy, MD

Case 45
A 23-year-old man with no known medical history is brought to the operating room (OR) from the emergency room (ER) with a gun shot to the abdomen. The patient states that he has no medical problems, takes no medicines, and has no allergies. His last meal was lunch earlier in the day, approximately 6 hours ago.

The patient is restless and combative, though he has no signs of respiratory distress and can protect his airway. His blood pressure is 89/37 mm Hg, heart rate 112 bpm, respirations 26 breaths/min, and his SpO2 is 100 % on 10 L by face mask. He opens his mouth well, has a full beard, and an adequate thyromental distance. His neck has not sustained any injuries that would indicate cervical immobilization. His abdomen is tense. Intravenous access consists of two 16-gauge catheters in his upper extremity.

The ER nurse informs you that he received 2 L of normal saline and 2 U of packed red blood cells in the trauma bay. His hematocrit prior to the transfusions was 24%.

➤ How should the airway be secured?

➤ What special monitors are indicated?

➤ What anesthetic agents should be used?

➤ How should the patient be resuscitated?


ANSWERS TO CASE 45:
Penetrating Trauma and Massive Transfusion
Summary: A healthy, 23-year-old presents after a gunshot wound to the abdomen with signs of hypovolemic shock.

Securing the airway: Rapid-sequence induction and intubation with a cuffed endotracheal tube.

Special monitoring: In addition to standard American Society of Anesthesiologists (ASA) monitors, invasive arterial blood pressure monitoring and measurement of urinary output with a bladder catheter (such as a Foley) are strongly indicated. In this setting, urine output serves as a surrogate for success of resuscitation. Central venous pressure (CVP) monitoring may be helpful.

Anesthetic agents: Choice of anesthetic is guided by hemodynamic parameters. While inhalational agents and opiates should ideally be given in cases of extreme hypotension, all anesthetics can worsen the shock state. In this circumstance, scopolamine may be used for its amnestic properties.

Resuscitation: The treatment of choice in an acute trauma with massive blood loss is fluid replacement. A combination of packed red blood cells, fresh frozen plasma, cryoprecipitate, platelets, and balanced salt solutions are most appropriate.


ANALYSIS
Objectives
1. Highlight the differences between elective surgery and emergent trauma surgery.
2. Learn the concept of a “transfusion trigger” and massive transfusion protocol.
3. Understand the complications and consequences of massive blood transfusion.


Considerations
Any patient with a significant injury to the thorax, abdomen, or an extremity often requires emergent surgical exploration. He may have a major vascular injury, or organ damage that requires immediate surgical intervention. Adequate venous access is critical. If peripheral access is limited, a large central venous line is indicated. This patient has two large-bore intravenous lines, which are appropriate. Unless the patient is hemodynamically stable and the trip to the OR is for exploration only, invasive arterial blood pressure monitoring is usually indicated. This can be placed in ER or in the operating room, whichever is most expeditious.

If the patient is hemodynamically stable, he may have to go to radiology for imaging first to delineate the extent of injuries, followed immediately by a trip to the operating room. Given this patient’s hypotension, he must go directly to the operating room.

Patients who have suffered an acute trauma will have delayed gastric emptying; this added to any recent meals mandates they be given full stomach considerations for airway management. The most common approach is rapid sequence intubation with cricoid pressure and a cuffed endotracheal tube. The management of the trauma patient’s airway is sometimes more difficult than that of other emergency patients. This patient has a full beard, which sometimes camouflages a recessed chin heralding a difficult intubation. This possibility is noted, and the operating room team is prepared to perform an emergency tracheotomy if needed.

Undiagnosed hypovolemia may result from significant albeit occult bleeding, so the anesthesia team must be prepared for aggressive volume resuscitation.


APPROACH TO
Acute Penetrating Trauma

A gun shot or stab wound to the thorax or abdomen is a life-threatening emergency until proven otherwise. Penetrating chest wounds may require anything from a chest tube to a thoracotomy with cross-clamping of the aorta. Abdominal or extremity injuries that are not associated with hemodynamic instability may permit a CT scan for a more complete evaluation before surgery. Yet many injuries can be managed by the trauma team without proceeding to the operating room.

When the patient first arrives to the OR, the anesthesiologist should perform a quick assessment of the patient. The surgical staff can provide information on mechanism of injury or suspected injuries. Simply knowing the locations of entry and exit wounds can give one an idea of what structure(s) may be injured (vasculature, spine, liver, bowl, etc). The surgeons and any accompanying emergency room staff should be able to detail line placement and resuscitative measures. A quick assessment of the airway is critical.

The airway is often more difficult to manage in a trauma patient than in a patient presenting for another type of emergency surgery. The trauma patient may be intoxicated or unable to cooperate with an airway examination. A deforming injury to the face or neck, or a previously undiagnosed occult injury may complicate laryngoscopy. Hemorrhage from the nose, pharynx, or mouth can obscure a view of the vocal cords. Trauma patients may vomit before or during induction. An experienced anesthesiologist can learn a lot by assessing external factors like thyromental distance, neck circumference, and tongue size.

If airway management will likely be difficult, the decision must be made to either proceed with induction and laryngoscopy, or to take extra time to perform an awake intubation or tracheostomy. The patient’s injuries, hemodynamic status, and ability to cooperate determine which direction to take. If the decision to proceed with induction and laryngoscopy is made, a rapidsequence induction with cricoid pressure should be performed. The patient may have recently eaten, and acute trauma decreases gastric emptying. Ordinarily, a rapid-sequence induction is performed with succinylcholine, so if the patient cannot be intubated, he is allowed to emerge, and an awake fiberoptic intubation is performed. Trauma victims with burns or denervation injuries can safely receive succinylcholine if the injury occurred less than 24 hours previously: the risk of hyperkalemia is not increased immediately after such injuries. Rocuronium at 1.2 mg/kg or vecuronium 0.2 mg/kg can also provide rapid intubating conditions if a nondepolarizing agent is preferred. Following the administration of nondepolarizers, a failed intubation leads to a surgical airway. Similarly, if a patient is unstable and surgery must proceed, allowing a patient to emerge from anesthesia after a failed intubation is not a reasonable option and a cricothyroidotomy is performed.

Cervical collars make positioning for intubation difficult. The patient’s neck must be kept in a neutral position, with care made not to extend the head during laryngoscopy. Alternatively, the cervical collar is removed, and the neck is stabilized by an assistant throughout airway manipulation. Indeed, this technique of laryngoscopy with proper in-line stabilization is as effective as an awake fiberoptic intubation at protecting the patient from further c-spine injury.

Hemorrhage and/or hypotension favor using an induction agent associated with hemodynamic stability such as etomidate. Ketamine may also be a good choice, as it causes release of endogenous catecholamines. However, it should be remembered that ketamine is a direct myocardial depressant, and in someone whose sympathetic response is already blunted (eg, an individual on betablockers), ketamine can result in a precipitous drop in blood pressure.

A patient who is severely hypovolemic may not tolerate the induction of anesthesia. In extreme cases, it may be necessary to intubate with succinylcholine alone. Preservation of life trumps the possibility of intraoperative recall, an inherent risk of trauma surgery. Fortunately, cognitive impairment secondary to hypotension, intoxication, or traumatic brain injury helps decrease this risk. Scopolamine 0.2 to 0.4 mg i.v. can decrease the risk of awareness or recall by causing central anticholinergic confusion. These patients often already have rapid heart rates from pain, sympathetic surge from their injuries, and from hypovolemia; so scopolamine often does not further increase heart rate. One troublesome effect of scopolamine is papillary dilatation, which can confound efforts to assess neurological status in the patient who is intubated and paralyzed. Once bleeding is controlled and volume replacement has been given, patients will often tolerate a volatile anesthetic and narcotics.

Resuscitation is accomplished by a combination of crystalloid and colloid administration. Crystalloid balanced salt solutions, such as normal saline, Plasmalyte, and lactated Ringers, are inexpensive and easy to obtain. They are often chosen for initial volume replacement. If the source of bleeding is easily diagnosed and quickly controlled, crystalloids may be all that a patient requires. In patients with hemoglobin values above 7gm/dL but mild hypovolemia, colloids such as albumin or hetastarch (Hespan) may be administered.

However, penetrating trauma frequently involves significant and extensive bleeding that necessitates blood and blood product transfusion. Packed red blood cells (PRBCs) may constitute much of the fluids given. Trauma centers will often have uncross-matched O-negative blood available on hand for immediate use; a blood sample should be sent as soon as possible so the blood bank can prepare type-specific, cross-matched blood products. As long as the patient has received PRBC and not whole blood, cross-matched blood products can be given as soon as they are available. If the blood bank’s supply of O-negative blood is critically low, a male patient can usually be given O-positive blood without suffering an acute transfusion reaction. Transfusion of Rh-incompatible blood results in delayed reactions that are not usually life threatening and can be followed later. Rh-negative women of reproductive age should be given Rh-immune globulin (Rhogam) prophylaxis until their blood type is known.

Massive transfusion, the replacement of more than one blood volume in a patient in less than 24 hours, carries special risks. Potassium increases in PRBCs, particularly as their unit ages. Potassium from this source can materially increase serum potassium levels, especially in the patient who is acidotic. Stored blood also contains citrate as an anticoagulant, which binds serum calcium. While the liver rapidly metabolizes citrate, rapid transfusion of large volumes of blood products can result in hypocalcemia. Hypocalcemia can in turn exacerbate both the hypotension and the coagulopathy, worsening the situation in the trauma patient. Blood is also cold: it is stored in the blood bank at 4°C (39.2°F). Thus a fluid warming device should be used for all cases where blood products are administered rapidly to prevent hypothermia (which can also worsen a coagulopathy). Lactate from anaerobic metabolism of red blood cells in PRBC can cause or worsen metabolic acidosis. Electrolytes and arterial blood gasses should be checked periodically, and metabolic abnormalities corrected accordingly. Levels of 2,3-DPG are reduced in red cells that have been stored a long time, causing a left shift of the oxygenhemoglobin dissociation curve. This left shift may be offset by local tissue acidosis in the hypoperfused patient.

Dilutional coagulopathies follow the infusion of large volumes of PRBC and crystalloids. Current recommendations for massive transfusion are to transfuse 1 U of FFP for every unit of PRBC transfused. The FFP is given empirically, rather than waiting for coagulation laboratory results. The factor that reaches low levels the earliest is often fibrinogen. While FFP usually contains adequate fibrinogen, cryoprecipitate may occasionally be a useful adjuvant as it is rich in fibrinogen. Both FFP and cryoprecipitate need to be given through a fluid warmer. Massively transfused patients can also develop a dilutional thrombocytopenia. Low platelet levels can result in microvasular bleeding that can be almost impossible to control without transfusion. Platelets do not need to be warmed, as they are stored at warmer temperatures. Platelets should be given more slowly than other fluids. The rapid administration of platelets can cause platelet rupture, the release of vasoactive metabolites, and hypotension.


Comprehension Questions

45.1. A 19-year-old man comes to the operating room for exploratory laparotomy after sustaining stab wounds to the chest and abdomen. His breathing is labored; the only intervention in the emergency room was administration of 1 L of normal saline. After rapid-sequence induction and intubation, peak airway pressures are 51 and delivered tidal volumes are 110 mL. After intubation, HR increases from 111 to 132; BP drops from 97/50 to 81/36. Which of the following is the next appropriate step?
A. Rapid infusion of 2 L of normal saline.
B. Check the endotracheal tube placement.
C. Immediate chest tube placement on the side of the injury.
D. Lighten the anesthetic.

45.2. A 32-year-old man is brought to the OR for surgical exploration of a stab wound to the neck. The entrance wound is just below the angle of the mandible in the mid-cervical spine. He was intubated in the ER. There is only a small hematoma, and bleeding is mild. His blood pressure is 68/32 mm Hg with a heart rate of 47 bpm. There are no other injuries. How should the patient be resuscitated?
A. Infusion of PRBC and normal saline in a 1:1 ratio
B. Infusion of epinephrine and normal saline
C. Rapid infusion of 3 L of normal saline
D. Infusion of isoproterenol and PRBC

45.3. A 24-year-old is in the OR after a gunshot to the abdomen. The surgeons are repairing a perforation in the small bowl. The patient has been stable for about an hour, and the urine output is 1 cc/kg/h. The patient suddenly becomes hypotensive after they accidentally cut the inferior vena cava. The patient loses 1500 cc of blood before the bleeding is brought under control. Using a rapid infuser, you infuse 5 U of PRBC (about 1500 cc) in 5 minutes. The patient is still hypotensive. Which of the following is your best option?
A. Give calcium chloride.
B. Give three more units of PRBC.
C. Give 2 L of normal saline.
D. Start a vasopressin infusion.


ANSWERS
45.1. C. The patient has a tension pneumothorax and requires immediate decompression. There is an injury to the lung. While the patient was breathing spontaneously, a pneumothorax may have been slowly enlarging. When positive pressure ventilation was initiated after intubation, however, the pneumothorax rapidly expanded. A tension pneumothorax can be recognized by hypotension (inadequate venous return from high intrathoracic pressures resulting in decreased preload), high airway pressures/inadequate ventilation, a shift of the trachea away from the injured side, and decreased breath sounds on the side of the injury.

45.2. B. This patient is suffering from spinal shock secondary to transaction of the spinal cord. Significant lesions high in the spinal column can cause a massive sympathectomy, with resultant vasodilatation and venodilatation in most of the vascular beds of the body. This leads to venous pooling (decreasing preload) and a very low systemic vascular resistance. Additionally, the cardioaccelerator fibers that innervate the heart (T1-T4 innervation) have been lost. This limits the body’s ability to compensate with a tachycardia and increased contractility. The treatment of choice is pharmacologic replacement of the sympathetic nervous system. In the absence of significant bleeding, concurrent administration of a balanced salt solution to correct the new relative hypovolemia is appropriate. Spinal shock typically resolves after several weeks as the patient develops a new homeostatic equilibrium.

45.3. A. This patient has hypocalcemia. Rapid infusion of large amounts of blood products can result in citrate toxicity. Citrate is used as an anticoagulant in stored blood products. When given more slowly, it is rapidly cleared by the liver. In massive transfusion situations, however, citrate levels can be critically low. The hypocalcemia can cause hypotension and a coagulopathy.


Clinical Pearls
➤ Trauma patients come to the OR with significant physiologic derangements including hypotension, hypovolemia, academia, and anemia. Anesthetic care may be directed entirely at resuscitation for several hours until surgical stabilization of injuries has occurred.
➤ Injuries can complicate airway management in a situation where performing a controlled, awake intubation is not an option.
➤ PRBCs may cause hypothermia, hyperkalemia, hypocalcemia, acidosis, and a shift to the left of the hemoglobin dissociation curve.
➤ If massive transfusion of PRBC is performed, FFP should be given empirically in a 1:1 ratio to prevent a dilutional coagulopathy. Dilutional thrombocytopenia must also be treated.

References

Dutton RP, McCunn M. Anesthesia for trauma. In: Miller RD, ed. Anesthesia. 6th ed. Philadelphia, PA:Elsevier; 2005: 2451-2495. 

Perkins JG, Cap AP, Weiss BM, Reid TJ, Bolan CE. Massive transfusion and nonsurgical hemostatic agents. Crit Care Med. 2008;36 (suppl. 7):S325-S339.

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