Dissecting Abdominal Aneurysm - Nursing Case Study
Pathophysiology
• Primary mechanism: Dissecting abdominal aneurysm (AAA) primarily occurs due to weakening of the aortic wall. This weakening is often associated with atherosclerosis where the buildup of plaque damages and weakens the arterial wall, leading to its expansion.
• Secondary mechanism: Hypertension exacerbates the situation as high blood pressure puts additional strain on the weakened aortic wall, further stretching it. This can result in the formation of a false lumen or channel inside the aortic wall where blood gets trapped and can cause the aneurysm to expand or rupture.
• Key complication: The main risk with AAA is rupture, which can lead to life-threatening internal bleeding. The larger the aneurysm, the higher the risk of rupture. Often, there are no symptoms until rupture occurs, making early detection and management critical.
Patient Profile
Demographics:
65-year-old male, retired construction worker
History:
• Key past medical history: Hypertension, High LDL cholesterol, Type II Diabetes, Smoker for 40 years
• Current medications: Lisinopril, Metformin, Atorvastatin, Aspirin
• Allergies: No known drug allergies
Current Presentation:
• Chief complaint: Sudden severe pain in the abdomen and back
• Key symptoms: Nausea, cold sweats, rapid heart rate, lightheadedness, fainting
• Vital signs: Blood pressure 160/90 mmHg, pulse 110 bpm, respiratory rate 22 breaths per minute, temperature 98.6 F, oxygen saturation 92% on room air
Section 1
New Diagnostic Results:
Upon arrival to the emergency department, the patient was immediately sent for a CT scan. The results confirmed the presence of a sizeable abdominal aortic aneurysm measuring 7.5 cm. The imaging also indicated signs suggestive of early dissection, with a small amount of blood visible in the peritoneal cavity. Additionally, a complete blood count showed a declining hemoglobin level, currently at 10.2 g/dL from a baseline of 14.5 g/dL, indicating possible ongoing bleeding. The patient's serum creatinine was elevated at 1.8 mg/dL, suggestive of compromised renal perfusion due to the AAA and his baseline was known to be 1.0 mg/dL.
Change in Patient Status:
Despite initial management with pain control and IV fluids, the patient's vital signs showed a trend of instability. His blood pressure increased to 180/100 mmHg, and his pulse is now 120 bpm. His oxygen saturation dropped to 88% on room air, prompting the initiation of oxygen therapy via nasal cannula at 3 liters per minute, improving his saturation to 94%. The patient reported an increase in his abdominal pain, rating it as an 8 out of 10. His skin became increasingly pale, and he began to show signs of restlessness and confusion, possible indicators of hypoperfusion and onset of shock.
This evolving scenario requires immediate surgical consultation for potential repair of the aneurysm and underscores the need for vigilant monitoring and management of the patient's hemodynamic status, pain, and renal function. It is critical to consider the patient's co-morbid conditions that can complicate his clinical course, including his hypertension, hyperlipidemia, diabetes, and history of smoking.
Section 2
New Complications:
The patient’s condition continued to deteriorate. An EKG showed new onset atrial fibrillation with a rapid ventricular response, further complicating the hemodynamic instability. The patient's urine output also decreased to less than 30 mL/hr, indicating worsening renal function. Due to the drop in urine output, the patient's serum creatinine level rose to 2.5 mg/dL, further indicating renal insufficiency. His hemoglobin level also continued to decline, now at 8.5 g/dL, underscoring the urgency of the situation.
Response to Interventions:
In response to the new complications, the medical team administered a bolus of intravenous fluids in an attempt to improve renal perfusion, and started the patient on a low dose of intravenous diltiazem to control the rapid ventricular rate associated with the atrial fibrillation. An urgent blood transfusion was initiated due to the continued drop in hemoglobin. Despite these interventions, the patient's blood pressure remained elevated at 190/110 mmHg and his pulse remained tachycardic at 130 bpm. His oxygen saturation, however, improved to 96% with oxygen therapy.
These findings heighten the urgency for surgical intervention to repair the AAA and address the hemorrhage. Continued vigilance in monitoring the patient's hemodynamic status, renal function, and responses to the interventions is crucial. The new onset of arrhythmia and deteriorating renal function presents added challenges to the management of this complex case.
Section 3
New Diagnostic Results:
A subsequent ultrasound revealed the aneurysm had expanded to 6.5 cm, significantly increasing the risk of rupture. In addition, a chest X-ray showed signs of pulmonary edema, suggesting possible congestive heart failure. The patient's prothrombin time (PT) and international normalized ratio (INR) were found to be elevated at 18 seconds and 1.8 respectively, indicating a potential coagulation disorder.
Change in Patient Status:
The patient's condition further worsened, with his blood pressure reaching 200/115 mmHg, and a heart rate of 140 bpm. He also developed acute respiratory distress, with respiratory rate increasing to 25 breaths per minute and oxygen saturation dropping to 90% despite oxygen therapy. The patient began complaining of severe abdominal pain, and on examination, his abdomen was distended and tender. His urine output further decreased to just 20 mL/hr, and his serum creatinine level rose to 3.0 mg/dL.
These new findings suggest that the patient's situation is becoming critical, with signs of possible aneurysm rupture, heart failure, coagulation disorder, and ongoing renal failure. The urgent need for surgical intervention is clear, but the patient's deteriorating condition and coagulation disorder present serious challenges. Careful clinical reasoning and immediate, targeted interventions are required to manage this complex case.
Section 4
Response to Interventions:
The patient was immediately started on intravenous nitroglycerin to rapidly reduce his blood pressure and alleviate the workload on his heart. Despite this, his blood pressure remained elevated at 190/110 mmHg and heart rate at 135 bpm. Morphine was administered to manage his severe abdominal pain and anxiety, with a slight improvement noted in his respiratory rate dropping to 23 breaths per minute, and oxygen saturation improving to 92%.
However, his distended abdomen remained tender and his urine output did not improve significantly, remaining at around 25 mL/hr, indicating ongoing renal dysfunction. His serum creatinine level continued to rise, reaching 3.2 mg/dL, and a subsequent lab test showed a further increase in his PT and INR to 20 seconds and 1.9 respectively, signaling worsening coagulation disorder.
These results indicate that while some interventions have had a modest effect, the patient's state remains critical, and his aneurysm is at high risk of rupture. His unresponsive hypertension, coagulation disorder, and renal dysfunction complicate the decision for surgical intervention. This necessitates further clinical reasoning to adjust the treatment strategies and consider alternative options to stabilize the patient's condition.
Section 5
New Diagnostic Results:
A repeat CT scan revealed an increase in the size of the aneurysm from 5.5 cm to 6.2 cm, indicating that the aneurysm was expanding rapidly. This is a clear sign of impending rupture, which could lead to a life-threatening situation. Additionally, the patient's complete blood count showed an elevated white blood cell count of 15,000 cells/mm^3, suggesting a possible systemic infection.
An arterial blood gas (ABG) analysis showed a pH of 7.28, partial pressure of carbon dioxide (PaCO2) of 55 mmHg, partial pressure of oxygen (PaO2) of 65 mmHg, and bicarbonate (HCO3-) of 22 mEq/L. These results indicate a respiratory acidosis with hypoxemia, which could be due to the patient's increased work of breathing and possible underlying lung disease.
The new diagnostic results show that the patient's condition is deteriorating. The increased size of the aneurysm, coupled with the worsening renal function, coagulation disorder, and now a possible infection and respiratory acidosis, pose significant challenges. This calls for a thorough evaluation of the current treatment strategy and considering the risk versus benefit of surgical intervention versus conservative management.