Case 24: Tibia Fracture



Fig. 24.1
ECG





24.1.4 Which Rhythm Disorder Is Present? What Causes It?


There is an irregular rhythm with a heart rate of >100 beats/min, in other words, irregular supraventricular tachycardia. The cycles deviate in length, so that the difference between the shortest and longest PP interval is >120 ms. Causes include a sinus node dysfunction, age, and digitalis intoxication.

Small variations of the PP interval (<120 ms) are normal and referred to as heart rate variability (HRV). A reduction in HRV is a sign of autonomic nervous system damage, as caused by diabetes, for example. A special form of sinus arrhythmia is respiratory arrhythmia, which is often found as a sign of vegetative dystonia in children and young adults.


24.1.5 Define Myocardial Contusion! What Are the Implications of a Myocardial Contusion?


Myocardial contusion is a traumatic damage to myocardial tissue. Five to fifty percent of blunt chest traumas result in myocardial contusion. It is often seen after motor vehicle and motorcycle accidents, deceleration accidents (such as falls), and certain high-velocity sports, such as baseball and lacrosse. Often additional injuries such as rib or sternum fractures or pulmonary contusions are present. Signs and symptoms are diverse and varied during the first 24 h and include:



  • Asymptomatic


  • Arrhythmia (usually sinus arrhythmias, extra systoles, ventricular tachycardias, even ventricular fibrillation)


  • Conduction disorders (right bundle branch block and AV block, because usually the right ventricle and septum are affected)


  • Repolarization disorders (unspecific ST- and T-wave changes)


  • Structural myocardial injuries with cardiac dysfunction (papillary muscle and valve injury, coronary dissection of the right coronary artery)


  • Cardiogenic shock

A serious cardiac contusion is more likely to be diagnosed than a mild one, since hemodynamic instability is usually the predominating sign [9]. However, nonspecific symptoms such as hypotension and tachycardia in trauma patients have countless other causes and can make the diagnosis more difficult.

The clinical diagnosis is confirmed by a 12-lead ECG, rhythm monitoring, echocardiography, cardiac enzyme tests, and possibly coronary angiography or myocardial scintigraphy. Of the biochemical markers, troponin is most helpful: initially and after 4–6 h, troponin T or troponin I values can confirm or rule out a diagnosis of cardiac contusion [8]. Continuous rhythm monitoring must be done for at least 48 h. Therapy with inotropes or an intra-aortic balloon pump may be indicated in severe cases. The most important differential diagnosis is a peri-traumatic myocardial infarction, which is a difficult diagnosis to make. Currently, a cardiac MRI with gadolinium is recommended for work-up [5].

>> Dr. Conall began with preoxygenation in order to get the induction done as soon as possible. Mr. Scott was agitated and uncooperative. By chance, anesthesia tech Cindy noticed the last line of the informed consent page; instead of the patients signature, there was only a wiry scribble.


24.1.6 Define Vegetative State!


The key requirement for diagnosis of a vegetative state is that there must be no evidence of awareness of self or environment at any time. This includes:



  • No response to visual stimuli


  • No response to auditory stimuli


  • No response to tactile stimuli


  • No response to noxious stimuli


  • No evidence of language comprehension or meaningful expression

If the vegetative state lasts for >4 weeks, it is called persistent vegetative state. After 1 year it is called permanent vegetative state.

Mr. Scott was agitated and uncooperative, meaning that he clearly reacted to different stimuli. The diagnosis noted on the preoperative evaluation was therefore incorrect. Mr. Scott was not in a vegetative state.


24.1.7 Evaluate the Patient’s Capacity to Give Informed Consent!


“Capacity” means that a patient has the ability to make a specific decision at a specific time [7]. To have capacity, patients must be able to understand their medical condition and understand the indications, risks, benefits, and alternatives to proposed treatments [7]. Due to Mr. Scott’s abnormal mental status from his traumatic brain injury, he is not capable of giving informed consent [7]. The patient’s next-of-kin, such as a parent, spouse, or sibling if spouse or parent is not alive, can provide informed consent for both surgery and anesthesia.

In emergency situations, two-physician consent is adequate, taking into account the assumed wishes of the patient. In contrast, elective procedures should be postponed until the next-of-kin can provide informed consent. If there is no next-of-kin, a court-appointed guardian can be obtained if the patient is not mentally competent.

In some cases, psychiatric consultation may need to be performed to determine if the patient possesses the competency to give informed consent.

>> Did Mr. Scott sign this himself?” she asked Dr. Conall. His only thought wasWhich of our anesthesiologists got that signature from him?” He shrugged his shoulders and said,“Lets get started. Time is running out.”

Dr. Conall asked anesthesia tech Cindy to give 300 μg fentanyl and 200 mg propofol IV. As the laryngeal tube size 4 was placed, Mr. Scott bit Dr. Conalls fingerhe was definitely not in a vegetative state. “Ouch! Dont bite me! Cindy, give him another 100 mg propofol!” The second try went well. Dr. Conall checked the placement, and anesthesia tech Cindy secured the laryngeal tube. As Dr. Conall set the mechanical ventilation (IPPV), the peak inspiratory pressures (PIP) were over 30 mmHg. A significant leak could be heard.


24.1.8 What Caused the Ventilation Problems?


Many causes could explain the ventilation problems:


24.1.8.1 Possible Causes of Ventilation Problems






  • Insufficient anesthesia depth.


  • Choice of the wrong size laryngeal tube (a size too small).


  • Tube misplacement. If the tube is not placed deep enough (ignoring the recommended and marked insertion lines), both cuffs can cause a partial obstruction.


  • Incorrect ventilator settings.


  • Individual patient causes such as:



    • Restrictive ventilation disorders, such as reduced pulmonary compliance as a result of the pneumothorax, pleura effusions, hemothorax, pulmonary contusion, rib cage fractures, and interstitial pulmonary fibrosis


    • Limited thorax movement as a result of kyphoscoliosis

>> Dr. Conall gave another 100 mg propofol IV and repositioned the laryngeal tube. The ventilation pressures were still high and the leak still present. Dr. Conall felt the reduced lung compliance when he attempted manual ventilation.


24.1.9 What Would You Do Now?


The airway is not secure. The underlying cause is the chest trauma, which is not expected to improve in time to correct the ventilation problems for this procedure. In addition, the duration of surgery is not clear. High peak pressures caused by pulmonary or other anatomical changes are a contraindication for the use of a laryngeal tube. Since the risk of undesired stomach inflation with regurgitation and possible aspiration must be avoided, there is clear indication for securing the airway via endotracheal intubation.

>> Dr. Conall let anesthesia tech Cindy give 45 mg atracurium and 200 μg fentanyl IV. After 3 min, he intubated the trachea of Mr. Scott without incident. The ventilation was currently being performed in the BIPAP (“biphasic positive airway pressure”) mode. It remained stable and unremarkable throughout the entire procedure. The external fixation was removed, and after 2 h the tibia fracture was treated with an intramedullary rod. Finally, an arm cast was scheduled to be changed under general anesthesia. Dr. Conall reduced the depth of anesthesia and asked the circulating nurse to call for the next patient as he was almost ready to begin emergence.

Anesthesia tech Cindys phone rang. “Ive got to go to an emergency in Admissions!” she reported and then promptly left Dr. Conall alone. “Ill be fine without you!” he called after her. Dr. Conall shut off the anesthesia as the cast was being placed. The janitors began removing garbage bags and used equipment to quickly ready the room for the next patient. Shortly thereafter, Mr. Scott woke up and began flailing around.

You still need to practice a soft landing,” said a surgeon furiously to Dr. Conall. “The cast isnt dry yet!” Nasty comments from the surgeons were nothing unusual. Mr. Scott threw his head from side to side, but he did not react to commands and he fought the tube. “Should I extubate or deepen the anesthesia?” wondered Dr. Conall as he held the tube and the head with both hands. The propofol syringe was not within reach, and no new pain stimulus was expected, so he decided to extubate immediately. He forgot to check for the oxygen mask, which had been removed by the janitor with the garbage bags.

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Sep 18, 2016 | Posted by in ANESTHESIA | Comments Off on Case 24: Tibia Fracture

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