acute aortic dissection is defined as the rapid development of a false , blood - filled channel within the tunica media of the aorta .
three acute aortic dissections are ultimately diagnosed out of every 1000 emergency department patients presenting with acute back , chest , or abdominal pain .
mortality in untreated acute aortic dissection is estimated at more than 1% per hour after the onset of symptoms , whereas 30-day survival for appropriately treated patients is greater than 80% .
therefore , the timely diagnosis and rapid management of acute aortic dissection are of paramount importance to the emergency physician . diagnosis is delayed more than 24 hours after the initial presentation in almost half of all cases , highlighting the need for emergency physicians to maintain appropriate clinical suspicion for acute aortic dissection in patients with chest , back , or abdominal pain .
failure to diagnose acute aortic dissection carries a significant risk for poor outcomes because of the consequences of progressive disease ( e.g. , aortic rupture ) and the possibility of treating a falsely diagnosed myocardial infarction ( mi ) or pulmonary embolism ( pe ) with anticoagulation , a potentially catastrophic error .
surgery on the aortic arch requires cardiopulmonary bypass , profound hypothermia , and a period of circulatory arrest .
focal and diffuse neurologic deficits are the major complications associated with the resection of the aortic arch , occurring in 3% to 18% of patients .
a 38-year - old woman was admitted to the emergency room with chest pain and dyspnea .
the patient s past surgical history was the bental operation , performed 7 years earlier , and the stenting of the descending aorta 6 months previously due to aortic dissection .
the patient s medical history was significant for hyperthyroidism and asthma , and her physical examination revealed blood pressure of 160/90 mmhg , heart rate of 90 beats per minute , metallic sound on heart auscultation , reduced breathing sounds in the left lung on lung auscultation , soft abdomen without tenderness , and symmetric and present peripheral pulses in the extremities .
additionally , the electrocardiogram ( ecg ) showed normal sinus rhythm and 1-mm st depression in leads avl , v5 , and v6 , and chest x - ray demonstrated a white left lung .
( figure 1 ) chest x - ray showing extreme dissection of the aorta ( arrows ) echocardiography demonstrated normal left ventricular chamber size , no left ventricular hypertrophy , moderate reduction in systolic function , global wall motion abnormality , ejection fraction of 35% , smoky pattern in the left ventricle , normal left atrium , normal right ventricle size and no right ventricular hypertrophy , normal mitral valve and no mitral stenosis or mitral regurgitation , normal hemodynamic of the aortic valve prosthesis ( aortic valve replacement was performed 7 years earlier ) , normal prosthetic ascending aorta , aneurismal descending aorta , normal flow pattern of the descending thoracic aorta , and a large aneurysm ( 8  5 cm ) filled with clot at the proximal portion of the descending aorta with reduced blood flow in the true lumen and deviation of the flow in the abdominal aorta - suggestive of aortic dissection .
echocardiography also revealed normal pulmonary valve with no pulmonary stenosis or pulmonary insufficiency , normal tricuspid valve with trivial tricuspid regurgitation but no tricuspid stenosis , normal drainage of the pulmonary vein , greater systolic pressure than diastolic pressure , no ventricular septal defect , no atrial septal defect , normal inferior vena cava with 50% respiratory variation , and no pericardial effusion .
ct angiography of the aorta with contrasted media revealed remarkable dilatation of the descending thoracic aorta ( 100-mm total transverse diameter ) due to aortic aneurysm without active dye flow - containing thrombosis , a stent containing flow inserted in the aorta ( figure 2 ) , normal aorta at the root and the ascending portion , mild pleural reaction in the left pleural space , evidence of dissection with flow in the true and false lumens of the abdominal aorta , flow in the renal arteries , enlarged left ventricular chamber , and normal main pulmonary artery and pulmonary artery branches .
coronal reformatted image , demonstrating the dissection of the aortic arch , involving the innominate and left common carotid arteries .
( complete arrows show false lumens and head arrows show true lumens ) aortography showed a significant endoleak ( type i ) from the proximal part of the graft into the false lumen .
the patient had sinus tachycardia ( 140150/min ) , which was treated with metoral ( 100 mg / tds ) .
two arterial lines were inserted in the right radial and right femoral arteries to monitor the blood pressure above and below the aortic arch .
the involvement of the aortic and carotid arteries , given the fact that the patient had dissection and aneurysm as well as tachycardia and high blood pressure , rendered perianesthetic cerebral oxygenation extremely crucial .
it is absolutely vital that all the above - mentioned factors be meticulously controlled in order to prevent the aggravation of the patient s conditions .
overall , our anesthetic plan - including techniques , drugs , and monitoring for this complicated case - was individualized to enhance the outcome of the procedure .
indeed , a rationale existed for choosing the right radial and right femoral artery for invasive pressure monitoring .
furthermore , right radial arterial pressure monitoring was important because the procedure required clamping of the left subclavian artery and femoral arterial pressure monitoring allowed us the assessment of distal aortic perfusion .
anesthesia was induced by using sufentanil in incremental and titrated doses up to 20 cc , propofol in incremental and titrated doses up to 20 mg , and cisatracurium ( 0.2 mg / kg ) .
additionally , neuromuscular block was monitored with a nerve stimulator with train of forth ( t.o.f ) mode to ensures adequate neuromuscular block . while in deep anesthetic state and deep neuromuscular block , the patient was intubated without any bucking and hemodynamic changes . for hemodynamic management during instrumentation ,
anesthesia maintenance was achieved using the balanced technique , utilizing propofol infusion ( 75100 mcg / kg / min ) , narcotic ( sufentanil [ 12 mcg / kg / h ] ) , and cisatracurium ( 2 mcg / kg / min ) .
hemodynamic management was accomplished by maintaining the central venous pressure between 12 and 16 cmh2o in tandem with the infusion of tng ( 1050 mcg / min ) and sodium nitroprusside at an infusion rate of 1.55 mcg / min .
bolus doses of esmolol ( 0.51 mg / kg ) were delivered via the central venous pressure line to control unexpected tachycardia .
in addition to invasive blood pressure , central venous pressure , temperature , heart rate , ecg , and end tidal co2 monitoring , the patient was monitored during the entire time of anesthesia and procedure with bilateral regional cerebral tissue oximetry ( rso2 ) with the invos in which regional saturation system measures changes in oxygen saturation levels beneath the sensor , allowing doctors and nurses to measure site - specific oxygen saturation levels .
troy mi ) ensures adequate bilateral hemispheral oxygenation . during anesthesia and procedure , especially during carotid clamping , rso2 was above 60% , which is higher than the acceptable lower limit of rso2 ( 55% ) ( 67% in the right side and 66% in the left side ) .
right clamp time was 25 minutes and left common carotid clamp time was 20 minutes .
basal activated clotting time ( act ) , measured for coagulation monitoring , was 100 seconds .
heparin ( 100 mg ) was administered , and second act was measured to be 345 seconds .
after mid - sternotomy , the innominate and left common carotid arteries were found dissected ; accordingly , proximal and distal control was done .
first , a 16 gel - sealed tube was anastomosed to the side of the ascending graft and then an end - to - side anastomosis to the innominate artery was performed . for the left common carotid artery ,
a 12 gel - sealed tube was anastomosed end to side to the ascending aorta graft and thereafter end to end to the left common carotid artery without cardiopulmonary bypass ( figure 3 ) .
she had only a moderate rise in creatinine ( up to 3.84 mg / dl ) , which later returned to the normal value of 1.61.9 mg / dl during hospitalization .
she was followed up for 4 weeks and then monthly for one year , during which time no problems were detected .
end - to - side anastomosis of the innominate ( black arrow ) and left common carotid arteries ( white arrow ) to the ascending aorta
in aortic arch dissection , monitoring of vulnerable organs and careful management are crucial . in the case of the involvement of arteries which supply the brain blood flow , monitoring of end - organ oxygenation
near - infrared photons are injected into the skin over the forehead . after being scattered about inside the scalp , skull , and brain ,
some fractions of the injected photons survive to return and exit the skin ( reflectance ) . by measuring the quantity of the returning photons and their wavelength
, one can infer the spectral absorption of the underlying tissue and make some conclusion about its average oxygenation . to reduce the interference of extra - cerebral oxygenation ,
invos utilizes two source detectors in spacing : a  near  and a  far  source detector .
theoretically , subtraction of some of the near signals from the far signals should leave a signal origination , predominantly in the brain cortex .
the potential for neurological injury is the achilles heel of aortic and heart surgery , but the technological advancement and innovations in anesthetic techniques have allowed us to offer surgical treatment to patients at the highest risk for neurological injury .
near - infrared spectroscopy devices demonstrate a significant correlation with cerebral venous oxygen saturation monitoring ( sjo2 ) and mixed venous oxygen saturation .
yamamoto - k et al . reported that near - infrared spectroscopy is suitable for monitoring immediate change in oxygenation during carotid surgery .
monitoring the cerebral rso2 in coronary artery bypass graft surgery patients prevents profound cerebral desaturation and it is associated with significantly lower incidence rates of major organ dysfunction . as was mentioned in the previous paragraphs , in the case of the dissection of the aortic arch and its branches , we can handle the aortic arch branches without cardiopulmonary bypass but by using rso2 , which prevents cerebral ischemia . in this complicated case study ,
patient had previously undergone aortic valve replacement and had a large number of coexisting medical conditions such as replacement of the ascending aorta and intra - arterial proximal descending aortic stenting .
therefore , debranching of the aortic arch branches was performed via meticulous control of hemodynamic and brain oxygenation as well as rso2 instead of cardiopulmonary bypass or deep hypothermic circulatory arrest . to our knowledge , this technique has not been previously reported in literature and may extend to a larger subset of patients who might otherwise have been excluded .
in addition , regional oxygen saturation correlates well with the mean flow velocity during carotid clamping .
it appears that cerebral oximetry is a satisfactory and possibly superior device for monitoring the adequacy of cerebral perfusion and oxygenation during carotid endarterectomy ( cea ) in comparison with transcranial doppler ( tcd ) .
the validity of rso2 also has been assessed by comparison with direct microprobe measurement of brain tissue oxygen partial pressure and reasonable agreement between these two measures has been found .
the pre - induction baseline brain rso2 for this case was right 80% and left 70% .
previous studies have stated that a brain rso2  50 scale units appears to represent an increased risk for hypoxic injury and that a drop by 20% below baseline is clinically important . in the case of our patient - at
any given time during anesthesia and procedure , the rso2 values were not below 50% scale units or 20% below baseline .
this case presented a rare challenge of handling aortic dissection without cardiopulmonary bypass , only by using rso2 .
this method prevents cerebral ischemia without any profound neurologic complications due to the use of cardiopulmonary bypass and deep hypothermic cardiac arrest .
further debranching of the aortic arch , especially vertebral arteries debranching with this method , requires further investigations .
 abstractaortic dissection begins with the formation of a tear in the aortic intima , and it directly exposes an underlying diseased medial layer to the driving force of the intraluminal blood . 
 this blood penetrates the diseased medial layer and cleaves the media longitudinally , thereby dissecting the aortic wall . 
 herein , we report the case of a 38-year - old woman , who presented with chest pain and dyspnea . after physical examination , laboratory evaluation , echocardiography , and ct  angiography , extensive aortic dissection was diagnosed involving the innominate and left common carotid arteries . 
 accordingly , the debranching of the aortic arch arteries was performed . during the procedure 
 , the patient was monitored with bilateral regional cerebral tissue oximetry . 
 the patient did not show any signs of complications either in the postoperative period or at postoperative three - month weekly follow - up or at subsequent monthly follow - up for the past year . 
Introduction
Case Report
Discussion
Conclusion