GSW Case Study Discussion

Acute loss of 35% of the blood volume can be fatal. In the healthy adult, a 15% loss of blood volume does not require intervention with intravenous fluids. Blood loss has different effects on the cardiovascular system, and it can be assessed by obtaining filling pressures of the right and left heart. The central venous pressures are normally low and have little margin for change when hypovolemia develops. A decrease in the central venous pressure of 4 to 5 mm Hg in the upright position can indicate hypovolemia. Other indicators of blood loss include the red blood cell (RBC) count and the hemoglobin (Hgb) count. Counts below 4.6 million/ul for RBCs and 13 mg/dL for Hgb indicate severe hemorrhage. Our patient's RBC count was as low as 2.7 million/ul, and his Hgb count was as low as 8.8 mg/dL

A chest tube is used with the purpose of draining foreign material out of the pleural space of the thorax. This procedure is done in order to evacuate fluid like blood (hemothorax), or air (pneumothorax) in order to prevent external compression of the lungs. The drainage of fluid or air will avoid the occurrence of atelectasis or lung collapse. The procedure used to place the tube into the chest in known as a thoracotomy. When our patient's chest tube was first inserted, 400 cc of blood was immediately returned. This was due to the damaging effects of one of the bullets.

Pulmonary edema is the abnormal accumulation of fluid outside the vascular space of the lung. This occurs because fluid is filtered into the lungs faster that it can be removed. Pulmonary edema is classified as either high pressure or permeability pulmonary edema. High pressure pulmonary edema results from a volume/pressure overload of the pulmonary circulation. Permeability pulmonary edema results from an increased permeability of the pulmonary capillary membrane as seen in hemorrhage, trauma, and stroke. Fluid overload was determined in our patient by pressures measured through a pulmonary artery catheter. One of the pressures measured was the pulmonary capillary wedge pressure (PCWP). The PCWP is designed to measure the pressure in the left atrium. It can also be used to measure the tendency for an individual to develop hydrostatic pulmonary edema. Normal values for PCWP range from 4-12 mm Hg. While values greater than this can indicate fluid overload in the pleural space and the onset of pulmonary edema, clinically significant fluid overload is associated with values of 17 mmHg or more. Our patient's PCWP was 17 mmHg.

Different modalities are being used in the intensive care unit to help reduce fluid overload in the lungs. In this case, the patient received aerosolized Vodka and 100% O2. Frequent suctioning of tracheal secretions was also performed. The idea of giving our patient 50% Ethanol is based on the fact that it increases the surface tension of the bubbles in the lung and causes them to shrink in size, thus reducing airway obstruction and resistance. Administration of 100% O2 was necessary to try to maintain our patient's oxygenation at a optimum level. Gas exchange units were affected directly by fluid overload creating areas of low V/Q. The removal of excess of fluid from the lungs is optimized by frequent and aggressive suctioning. Effective suctioning was achieved by using a 14-Fr size catheter which was inserted into the patient's endotracheal tube. Suction of foreign liquid and sputum was then applied in an intermittent manner.

Ventilation to our patient was applied by using pressure control. In this mode, all breaths are mandatory (patient or machine triggered machine breaths) and are delivered by the ventilator at a preset frequency, pressure, and time interval. A set peak pressure is delivered, and the breaths end after a certain period of time has elapsed. This mode of ventilation is useful in preventing high pressures from distending the lungs. Considering the fragility of this patient's lungs due to the lobectomy, high pressures would be devastating. Pressure control, in this case, was used to provide inverse ratio ventilation (IRV). IRV is unnatural and uncomfortable, so our patient had to be sedated and paralyzed.

IRV is achieved by setting the ventilator to provide an inspiratory to expiratory ratio greater than 1:1. In other words, the inspiratory phase is longer than the expiratory phase. The patient in this case was exposed to inverse ratio ventilation to increase his alveolar ventilation. This concept is based on the principle that a certain pressure remains in the alveoli and keeps them open at the end of expiration. This allows for maximal alveolar recruitment and prevents alveolar collapse. Oxygenation improves as the functional residual capacity (FRC) increases.

The need to keep the patient paralyzed was no longer required when IRV was discontinued. He was then able to trigger ventilator breaths and resume some of the work of breathing to keep his respiratory muscles from getting too weak. In Continuous Mandatory Ventilation (CMV) mode a patient can trigger ventilator breaths and also receive breaths initiated by the ventilator should the patient's respiratory rate fall below the preset frequency on the machine. In this case, our patient received volume-controlled (VC) breaths when in CMV mode. Volume-controlled breaths differ from PC breaths in that a preset volume is delivered with each breath instead of a preset pressure. Therefore, peak pressures must be monitored closely to avoid barotrauma.

Red Man's Syndrome is a condition in which the patient's body turns to a red gloss or sheen, develops hypotension, and or experiences pruritis. This condition is precipitated by a rapid infusion of the antibiotic Vancomycin, which in turn follows a massive release of histamine.

Disseminated Intravascular Coagulation is a condition in which a patient may have excessive clotting, uncontrolled bleeding, or both. Infections are the most common cause. Our patient presented with disseminated intravascular clotting, which was the result of a widespread exposure of the circulating blood to procoagulant activity capable of activating the fibrinolytic enzyme system converting fibrinogen into fibrin. Fibrin in turn caused occlusion of the posterior tibial artery resulting in tissue necrosis and amputation of the limb below the knee.

There are several complications associated with a tracheostomy. Complications may occur from the surgical procedure (tracheotomy) or after the trach tube is in place. There are serious complications in 5% of all cases, and the actual tracheotomy has a reported mortality rate of 2-3%. Immediate postoperative complications include the risk for pneumothorax, stomal hemorrhage, and accidental decannulation. The most common general complication of a tracheostomy is a 50% chance that the patient will develop a pneumonia. Tracheal stenosis is also a major complication of a tracheostomy tube. While it may occur at the stoma site, it is more common at the site where the cuff seals the trachea. Tracheal stenosis is one of the most serious complications of a tracheostomy and often does not manifest itself until long after the patient leaves the ICU. Current practice of proper cuff inflation technique and the use of high-volume, low-pressure cuffs has drastically reduced the incidence rate of tracheal stenosis.

Usually a person who has a tracheostomy has been in the hospital for a long time due to a serious illness which required intubation. If the patient is expected to require an endotracheal tube for over two weeks, a tracheostomy is indicated. A tracheostomy allows mechanical ventilation for a prolonged period of time with greater patient comfort, oral food intake, and better mouth care.