Page 1599 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

1118 PART 10: The Surgical Patient

is identified and incised transversely. A pair of forceps is then inserted most common source of hypoperfusion in the multiply injured patient
to spread the opening, and a tube of appropriate caliber, usually a 6F or is hemorrhage. Its clinical presentation will depend on such factors as
7F tracheostomy or endotracheal tube, is inserted through the opening the patient’s age, as well as the duration and magnitude of the hem-
and secured. orrhage. The presence of a normal or even elevated blood pressure,
■ CERVICAL SPINE PROTECTION particularly in the young patient, does not rule out blood loss. The
physiologic response to hypovolemia includes sympathetic discharge
Many techniques for establishing an artificial airway are associated with with vasoconstriction and tachycardia, which will tend to maintain
risks of cervical spine injury. Awareness of these risks during airway the blood pressure. Older patients tend to manifest hypotension much
intubation is crucial in preventing spinal cord injury in the multiply earlier in the course of hypovolemia. Therefore, other signs of hypoper-
injured patient. Inappropriate manipulation of the cervical spine during fusion should be sought in assessing the trauma patient. In addition, a
airway intubation could convert an unstable cervical spine injury without systolic blood pressure of 90 mm Hg has been regarded as an early sign
neurologic deficit into one with permanent neurologic deficits, including of hypoperfusion. However, the sympathetic response to hypovolemia
paraplegia, quadriplegia, and even death. In a patient who is unconscious results in vasoconstriction, maintaining blood pressure at the expense
or who is suspected of having a cervical spine injury, the neck should not of tissue perfusion. A fall in blood pressure is therefore a late sign of
12
be flexed, extended, or rotated. In-line immobilization with the neck in hypoperfusion. The location and character of the pulse, the skin color,
the neutral position should be maintained while the airway is secured. and capillary refill time are all signs that are immediately accessible to
Although the orotracheal route is more commonly practiced, if the the examining physician and should be used in determining adequacy
patient is conscious and breathing, then a blind nasotracheal intubation of perfusion. Failure to palpate a radial pulse may signify hypotension of
may be attempted with cricoid pressure anteriorly. If the patient is apneic, the order of 70 to 80 mm Hg. Tachycardia with cool extremities suggests
then orotracheal intubation with in-line cervical immobilization will have hypoperfusion from hemorrhage until proven otherwise. Hemorrhage
5
to be attempted. Failure or inability to secure the airway by nonsurgical may be subdivided into classes I to IV, each class having an associated
means in a patient who requires a definitive airway necessitates cricothy- clinical response, as indicated in Table 117-1. The patient who has a
roidotomy. Where fiberoptic bronchoscopy or the gum elastic bougie is normal heart rate with a strong, bounding radial pulse, warm skin, and
immediately available, it may be used to facilitate endotracheal intuba- a capillary refill time of less than 2 seconds would be considered not to
tion. During the initial process of resuscitation spinal protection is the have lost any significant volume of blood, and the degree of deviation
7,8
main goal as opposed to spine imaging to diagnose a specific injury. All from these clinical parameters would correlate with the magnitude of
unconscious patients or patients suspected of cervical spine injury should blood loss.
have cervical spine imaging and all seven cervical vertebrae and the supe- Although the most common cause of hypoperfusion in trauma
rior aspect of the first thoracic vertebra should be clearly visualized. patients is hemorrhage, other causes, such as tension pneumothorax,
9,10
This is usually conducted after the patient has been resuscitated and in cardiac tamponade, myocardial contusion, open pneumothorax, and
many centers CT scan imaging is used rather than plain x-ray. If plain flail chest must be considered. Hypoperfusion in the trauma patient first
x-rays are used then, failure to visualize all seven cervical vertebrae and requires a search for a source of hemorrhage, which should be controlled
the top of the first thoracic vertebrae should necessitate other views of immediately. Any external source of hemorrhage should be controlled
the spine, including a swimmer’s view. An open-mouth anteroposterior by direct pressure, without resorting to blind application of clamps or
13
odontoid and anteroposterior x-ray view of the cervical spine should also tourniquets. In the military, tourniquets have been shown to have a
be done. If there is doubt as to the presence of a cervical spine injury, definite role in controlling major extremity hemorrhage. Improving the
the neck should be immobilized with a semirigid cervical collar and hemodynamic status should be the next goal. This should be accom-
computed tomography (CT) is performed to assess the integrity of the plished by appropriate fluid replacement through at least two large-
cervical spine. If the patient is awake and alert and has no cervical pain bore intravenous catheters (14-16 gauge minimum). It is very helpful
or tenderness or other abnormality on physical examination, then the to establish multiple IV catheters, not only to facilitate rapid volume
cervical collar may be removed after adequate cervical spine x-rays. In infusion, but to ensure that an IV line will still be available if one of the
the presence of clinical signs of spinal cord injury, the cervical spine is catheters becomes disconnected, plugged, or otherwise nonfunctional.
considered to be abnormal even if the cervical spine imaging appears In the adult, the preferred peripheral percutaneous intravenous site is
normal. In selected patients who have not had a period of unconscious- in the forearm or the antecubital vein. Failure to establish intravenous
ness or another painful distracting injury, and are alert and have no clini- access through these routes should prompt establishment of intravenous
cal evidence of cervical spine injury, imaging of the cervical spine may be access by other routes such as the internal jugular or subclavian vein
omitted and the cervical collar removed. 11 in the neck or femoral vein in the groin using the Seldinger technique.
Ultrasound guidance should be used where available for safe, accurate
■ VENTILATION placement of central venous lines. Venous cut-down of the saphenous
14
Adequacy of ventilation is quickly assessed by observation of the chest vein at the ankle or the antecubital vein or the femoral vein at the groin
are other approaches, but are now seldom necessary because of the
for asymmetrical or paradoxical movement, followed by quick ausculta- success in establishing access through the other nonsurgical routes.
tion and percussion to determine whether there is any hyperresonance The route will depend on the experience and skill of the physician.
or dullness to suggest pneumothorax or hemothorax. Deviation of Placement of central lines in the neck should always be followed by a
the trachea suggests the presence of a pneumothorax or hemothorax, chest x-ray as soon as feasible, not only to confirm proper location of the
but this finding is not always evident. Although one may confirm the catheter, but also to check for the presence of pneumothorax or hemo-
diagnosis of a simple traumatic pneumothorax with an upright chest x-ray, thorax. Because these lines are placed under less than ideal conditions,
suspicion of a tension pneumothorax requires immediate decompression, the risk of septic complications is high, and the lines should be replaced
without prior x-ray confirmation. Further examination of the chest should later under more sterile conditions. In children under age 6 years, the
be conducted to determine the presence of other life-threatening thoracic intraosseous route should be attempted before proceeding to the central
injuries, such as cardiac tamponade, open pneumothorax, flail chest, rup- venous routes. With specially designed devices the intraosseous route is
tured thoracic aorta, and massive hemothorax (see Chap. 120). also used in adults. As a rule, it is best to avoid placing IV catheters in
15
■ ADEQUACY OF PERFUSION limbs that have major soft tissue or bony injuries. The intensivist must
be completely familiar with the usual sites for venous access and also
After airway control, oxygenation, and adequate ventilation have been be prepared to proceed to venous cut-down where percutaneous and
secured, the next priority is maintenance of adequate perfusion. The intraosseous techniques are not successful. Venous access should be

section10.indd 1118 1/20/2015 9:20:10 AM