Question

Carlos Adams was involved in a motor accident and suffered blunt trauma to his abdomen. Upon presentation to emergency department, his vital signs are as follows:
Temperature, 100.9degrees Ferihieght, heart rate,120bpm, respiratory rate, 20 breast/min, and blood pressure, 90/54mmHg.His abdomen is firm,with bruising around the umblicus. He is alert and oriented, but complains of dizziness when changing positions. The patient is admitted for management of suspected hypovolemic shock.The following orders are written for the patient:
place two large-bore IVs and infuse 0.9% NS at 125mL/hr/line.
Obtain complete blood count, serum electrolytes oxygen at 2L/min via nasal cannula.
Type and cross for the 4 units of blood.
Flat plate of the abdomen STAT (Learning objective 1,4,and 5).
a. Describe the pathophysiologic sequence of events seen with hypovolemic shock.
b. What are the major goals of medical management in this patient?
c. what is the rationale for placing two large-bore IVS?
d. what are the advantages of using 0.9% NS in this patient?
e. What is the rationale for placing the patient in a modified Trendelenburg position?

Answer 1

Hypovolemic shock is also known as haemorrhagic shock. When more that 20% or one-fifth body fluid and blood is lost from the body, shock symptoms can occur. Blood pressure falls drastically and may result in life threatning situation. Acute external blood loss secondary to penetrating trauma and severe GI bleeding disorders are 2 common causes of hemorrhagic shock.

Answer a)

When there is a case of sudden injury, hemorrhage can occur and he body responds to it by activating the four following systems- a) hematologic, b) cardiovascular, c) renal and d) neuroendocrine system. The three act as the major physiologic systems.

-As the name suggests, the hematologic system responds to an acute severe blood loss. Then it activates the coagulation cascade and contract blood vessels that are bleeding with the help of thromboxane A2 release. Platelets are activated at the same time to combat blood loss. The clot is stabilized by fibrin deposition as the damaged blood vessel exposes collagen to the body to respond. In 24 hours a mature clot formation may be complete.

-The cardiovascular system initially responds to hypovolemic shock by increasing the heart rate, increasing myocardial (smooth muscles of the heart) contractility, and constricting peripheral blood vessels. This occurs due to increased release of nor-epinephrin and decreased baseline vagal tone (Vagal tone or Sinus arrhythmia refers to activity of the vagus nerve, an important component of the parasympathetic branch of the autonomic nervous system.) The response is regulated by the baroreceptors in the carotid arch, aortic arch, left atrium and pulmonary vessels of the cardiovascular system. The system also redistributs blood to the brain, heart, kidneys and away from the skin, muscles and GI tract (i.e.site of injury).

-The renal system responds by increasing rennin secretion from the juxtaglomerular apparatus. It converts angiotensinogen to angiotensin I, which subsequently is converted to angiotensin II by the lungs and liver, which help in the reversal of haemorrhagic shock, vasoconstriction and stimulate adrenal cortex to secrete aldosterone (to aid water conservation in the body through active sodium reabsorption).

- The neuroendocrine system increases the release of ADH or antidiuretic hormone from the posterior pituitary gland in response to decrease in blood pressure. It increases salt and water re-absorption by the distal tubule, the collecting ducts and loop on henle.

Without fluid and blood resuscitation and/or correction of the underlying pathology causing the hemorrhage, cardiac perfusion eventually diminishes, and multiple organ failure soon follows.

Answer b)

The workup depends on the history of the patient, physical examination and the cause oof haemorrhage. Iniially, Laboratory analysis include the CBC, electrolyte levels, lactate, prothrombin time, activated partial thromboplastin time, ABGs, urinalysis (in patients with trauma), and a urine pregnancy test ( in women). Blood should be typed and cross-matched to avoid mishap.

The main goals for treatment include the following-

1. Preventing further injury while transporting to the hospital.
2. Direct pressure should be applied to the bleeding site to avoid further blood loss.
3. Maximizing oxygen delivery - completed by ensuring adequacy of ventilation, increasing oxygen saturation of the blood, and restoring blood flow.
4. Control further blood loss and may require surgical intervention. Somatostatin and octreotide infusions have been shown to reduce gastrointestinal bleeding from varices and peptic ulcer disease.
5. Fluid resuscitation with a combination of saline and dextran. Many fluids have been studied for use in resuscitation; these include isotonic sodium chloride solution, lactated Ringer solution,hypertonic saline, albumin, purified protein fraction, fresh frozen plasma, hetastarch, pentastarch, and dextran 70.

Answer c)

The Poiseuille law (for fluid flow) states that flow is inversely related to the length of the IV catheter and directly related to its radius to the fourth power. Hence a shorter large-caliber IV is ideal.

IV access may be obtained by means of percutaneous access in the antecubital veins, cutdown of saphenous or arm veins, or access in the central veins by using the Seldinger technique. If central lines are obtained, a large-bore single-lumen catheter should be used. Intraosseous access has and continues to be used for hypotensive children younger than 6 years. Intraosseous access has also been used in hypotensive adults.The most important factor in determining the route of access is the practitioner's skill and experience.

Thus, to increase the flow of fluid to quickly control the loss of fluid, large-bore IV is placed immediately.

Answer d)

NS stands for normal saline. Normal saline is a mixture of salt and water. It is called normal because its salt concentration is similar to tears, blood and other body fluids (0.9% saline) and is isotonic to the body fluids. Thus, in this patient suspected with hypovolemic shock, NS will help resore balance in the body without changing its physiological state.

Answer e)

In the Trendelenburg position, the body is laid back in supine position with the feet higher than the head by 15-30 degrees. This is said to decrease cerebral pressure and help restore blood flow in the brain.
The modified position is a variant of the Trendelenburg position in which only the feet are elevated above the head. This is opposed to the traditional Trendelenburg position in which the entire bed is tilted. This technique is named after the famous German philosopher and surgeon Freidrich Trendelenburg. Doctors believed that directing more blood to the brain aided in recovery and minimized the amount of damage. But theory is hazy without proper research backing it up.