Running head: COMPLICATIONS OF VASCULAR SURGERY Postoperative Complications of Vascular Surgery: What Bedside Nurses Need to Know Deidre Dennison SUNYIT 1 Running head: COMPLICATIONS OF VASCULAR SURGERY 2 The term vascular surgery encompasses many different procedures involving repair, revision, or reconstruction of the vasculature of the human body. The most well- known major vascular condition is an aortic aneurysm, which may require surgical intervention to prevent emergency or fatal consequences. As with most surgeries, there are serious medical risks involved. The purpose of this paper is to serve as a tool for registered nurses caring for postoperative vascular surgery patients so that these nurses can be aware of serious complications of aortic aneurysm repair. Early identification and intervention of postoperative complications can have a major impact on patient’s morbidity and mortality. As with anything else, chance favors the prepared mind. The term aneurysm is from the ancient Greek for ‘widening’ (Woodrow 2011). This is essentially what happens along a portion of the major artery of the body in an aortic aneurysm. The aneurysm is better defined by its location along the large artery – ascending or descending as well as whether in the thoracic or abdominal region. This paper will focus on descending aortic aneurysms, both thoracic as well as abdominal, and identify the role of the bedside nurse in caring for this population. Early identification of the signs and symptoms of complications and prompt reporting of this to the surgeon, along with supportive measures, is paramount to increase the chance of favorable patient outcomes. In order to understand and truly appreciate the terms ‘dissection’ and ‘rupture’ as they refer to aortic aneurysms, one must be able to picture the anatomy of arterial layers. The innermost layer, the tunica interna (intima) is made up of a single layer of cells; the middle layer is known as the tunica media and is made up of smooth muscle and elastic tissue; and the collagen containing tunica externa (adventitia) is the outermost layer. When an aneurysm dissects, the blood passes into the tunica media through a damaged tunica interna. This increases Running head: COMPLICATIONS OF VASCULAR SURGERY 3 the risk for rupture, which is a medical emergency. According to Woodrow (2011), only one in three people who experience rupture in the community are likely to reach the hospital alive. Of those who reach the hospital, only half will survive the surgery and perioperative period. Symptoms of rupture include severe back pain which may radiate and is described as a ripping or tearing feeling. According to Vacca (2009), “Of the 200,000 people diagnosed with aortic aneurysm each year, rupture occurs in about 15,000, creating a life-threatening emergency” (p. 25). Those patients who experience rupture and survive have higher rates of complications than those who have elective surgical intervention. The complications that will be explored in this paper include renal impairment including acute renal failure, paraplegia, mesenteric ischemia, graft migration and leaking. A majority of the complications related to aortic surgery are a result of low perfusion states such as with rupture (shock) or thrombus, and cross clamping of the aorta during surgery. This paper will identify specific nursing interventions for the postoperative aortic aneurysm repair patient as well as signs and symptoms of complications. Typically, in the absence of symptoms, an aortic aneurysm is discovered either during routine physical examination or while the patient is being worked up for something else. In fact, according to Dolinger & Strider (2010), almost 80% of patients with descending thoracic aortic aneurysms are asymptomatic. If left undiscovered and therefore untreated there is a greater chance of rupture which carries with it a 94% mortality rate (p.147). The goal is for early identification, especially for those who have risk factors or common co-morbidities such as hypertension, coronary artery disease, diabetes, smoking and certain syndromes that may predispose a patient to aneurysms such as Marfan syndrome (Dolinger & Strider 2010). According to Woodrow (2011), symptoms of aortic aneurysm include back pain, weak peripheral Running head: COMPLICATIONS OF VASCULAR SURGERY 4 pulses, feelings of fullness, and abdominal pulsation. Signs specific to thoracic aneurysms include upper airway symptoms, dyspnea and cough. In the case of thin patients the pulsation may be visible, which may help identify the problem sooner. According to Vacca (2009), “Without treatment, a patient with a TAAA [thoracoabdominal aortic aneurysm] that’s twice the diameter of the uninvolved aorta has a 2-year survival of less than 30%” (p. 25). Once the aneurysm is identified, the next step is to determine a course of action. If the aneurysm is not thought to have a high risk for rupture, the plan is typically medical management using antihypertensives to achieve a goal blood pressure of systolic 90-120 mmHg and a mean arterial pressure of 65-75 mmHg. Also, avoiding straining associated with heavy lifting and modifying risk factors is important. These patients with known aneurysms that are being medically managed are required to undergo regular imaging studies every six to twelve months. Physicians typically base their recommendation for surgical intervention based on the size of the aneurysm. Although the literature varies between 5.5cm and 6cm, the general consensus is that surgical intervention is appropriate at that time as the risk of rupture increases at 6cm (Dolinger & Strider 2010). According to Woodrow (2011), once the aneurysm reaches 8cm in diameter the risk of rupture is 50% (p. 53). To put these measurements in perspective, the typical diameter of the infrarenal aorta (below the kidneys) in a middle aged patient is roughly 1.46cm – 1.68cm depending on sex (Vacca 2009). At the suprarenal level (above the kidneys), the average size is 2.5cm in diameter (Dolinger & Strider 2010). Increased age also plays a role in the risk of rupture as the collagen tissue becomes weaker, increasing the risk of aneurysm and subsequent rupture (Dolinger & Strider 2010). As stated, size of the aneurysm plays the largest role in the treatment decision; however in certain circumstances the physician and/or vascular surgeon may suggest surgical intervention for some patients including younger, typically female, patients with Running head: COMPLICATIONS OF VASCULAR SURGERY 5 no co-morbidities and an aneurysm size of 5cm – 5.4cm (Woodrow 2011). Those patients with Marfan syndrome are typically considered for surgical intervention when the aneurysm reaches over 5cm in diameter (Vacca 2009). An additional factor in surgical intervention is an increase in the rate of growth to 1cm per year with the average for medical management being approximately half that (Adams, Malcotti, & Petrunak 2007). Interestingly, it is documented that men tend to have a higher incidence of aneurysm, but women are more likely to rupture and subsequently suffer the associated medical complications (Woodrow 2011). The reason behind this increased risk for rupture in women is unknown. There are two approaches to surgical repair of an aortic aneurysm – endovascular and open (conventional). Generally speaking, endovascular approach is less invasive and offers lower perioperative risk, fewer hospital days, quicker recovery and is tolerated better by the patient (Dolinger & Strider 2010). However, the open approach repairs tend to offer more longterm effect as endovascular repairs tend to need to be redone in the future. Open approach patients also require less long-term imaging studies. In an endovascular approach the surgeon accesses the aortic aneurysm through the femoral artery by making inguinal incisions and deploying a stent graft in the area of the aneurysm. The stent graft is deployed so that it covers the areas proximal and distal to the aneurysm that are not affected in order to anchor it to healthy tissue. The stent graft provides a sort of structural barrier to prevent the blood from flowing into the aneurysmal sac; the sac will then shrink in size and as the coagulated blood within it is reabsorbed (Dolinger & Strider 2010). In order to be a candidate for endovascular repair there are some criteria that need to be met. The patient must have adequate vasculature for endovascular access, not have tortuous vessels, and not need concurrent renal artery repair. More and more patients are being treated endovascularly as appropriate because of the less Running head: COMPLICATIONS OF VASCULAR SURGERY 6 invasive nature of approach. According to Woodrow (2011), “the most serious complications of endovascular repair are endoleak (that occurs if blood flow persists between the aneurysm and the graft) and spinal cord ischemia” (p. 54). Nursing interventions for postsurgical care of the endovascular patient include general postoperative care such as monitoring respiratory status, level of consciousness related to anesthesia, correction of fluid and electrolyte imbalance, laboratory studies, and pain management. Interventions to pay particular attention to as they relate to this procedure include avoidance of hypertension as it can damage grafts; maintence of adequate mean arterial pressure (may be 80-100 mmHg) in order to facilitate adequate postoperative perfusion of organs as some patients are hypotensive after surgery secondary to anesthesia; monitoring for equality in baseline sensation and movement of extremities and assessment of distal pulses. In thoracic endovascular procedures the risk for spinal cord ischemia remains a potential complication. When long segments of graft are placed over the thoracic aorta it may block arteries that supply collateral circulation thereby increasing the risk for lack of perfusion of the anterior spinal artery (Dolinger & Strider 2010). In order to decrease the potential for this complication a spinal drain is inserted pre – or intraoperatively. After surgery the nurse uses this drain to maintain a spinal pressure of around 10mmHg by draining cerebrospinal fluid intermittently (Vacca 2009). As a result of keeping the spinal pressure low it decreases the pressure on the anterior spinal artery and increases circulation and perfusion (Vacca 2009). Nursing care for a spinal drain includes keeping the patient on bedrest, monitoring the quality of the cerebrospinal fluid, frequent neurological assessment - including positive movement and sensation, level of consciousness, headache, nausea - and monitoring the spinal drain point of insertion/dressing for any signs of dislodgement or infection. Running head: COMPLICATIONS OF VASCULAR SURGERY 7 In an endovascular leak or migration, the patient may experience discomfort, diminished, or absent pulses distal to the graft because of an interruption of blood flow. Loss of pulses anywhere, signs of cerebrovascular accident, or suspected pulmonary emboli could be a result of a piece of plaque or thrombus that is broken off during graft insertion (Dolinger & Strider 2010). In the conventional open approach the risk for complications increases because of the invasive nature of the procedure, and aortic cross clamping which is not done during endovascular repair. In aortic cross clamping the surgeon places clamps on either side of the aneurysm to isolate it and stop blood flow (Woodrow 2011). This interruption in blood flow can lead to spinal cord ischemia, mesenteric ischemia, and renal ischemia. One way surgeons try to avoid or minimize these complications is through limited clamp time, although that is not always feasible during surgery. In an open approach the patient will have a postoperative chest tube as the surgery requires a thoracotomy and deflation of the lung on the side used for the approach. This in itself places the patient at an increased risk for pulmonary complications. Nursing interventions specific to an open approach repair postoperatively include monitoring and controlling mean arterial pressure to ensure adequate perfusion but not high enough to risk damage to the segment repaired or ‘blow the graft’ as it is typically sewn in. Monitoring for postoperative bleeding is also an important consideration and includes assessing the surgical site dressing, typically a large flank incision, for increase in shadowing and frank bleeding; new onset or worsening hypotension, weak peripheral pulses, shock state symptoms, and rigid abdomen may indicate internal bleeding from a migrated or blown graft. Bleeding into the abdomen puts the patient at increased risk for abdominal compartment syndrome which in turn creates a low flow state to the mesenteric arteries and anterior spinal artery by placing pressure on these arteries as well as involving ischemia to other abdominal organs (Lee 2012). Running head: COMPLICATIONS OF VASCULAR SURGERY 8 According to a study published by Welten et al. (2007), “ postoperative decreased renal function is a well-known feared complication after major vascular surgery associated with longterm mortality” (p. 219). In this cited study the analysis included 952 patients who underwent abdominal aortic aneurysm repair, of which 27% had temporary worsening of renal function and 17% of patients suffered persistent worsening of renal function. Also of notable contribution is the association between perioperative blood loss as well as suprarenal aortic clamping time and worsening of renal function. This suggests a direct relationship between an increase in clamp time and postoperative complications. According to Welten et al. (2007), an acceptable or ‘safe’ clamp time of the suprarenal aorta is forty-five to fifty minutes. In this study the median clamping times for the patients with worsening renal function were higher than the suggested cut-off times. It is important for the bedside nurse to be aware of the possibility of renal function decline and monitor urine output along with laboratory studies such as elevated creatinine, blood urea nitrogen and decreased glomerular filtration rate. The nurse also notes decreases in electrolyte clearance by observing elevated potassium, phosphorus levels, among others. Elevated serum electrolytes can cause serious medical problems such as life-threatening cardiac dysrhythmias. Additional training is needed for the nurse who will be caring for the patient receiving continuous renal replacement therapy, which is therapy performed with the hope of not needing long-term hemodialysis. The final postoperative complication to be explored here is mesenteric ischemia, which is associated with abdominal aortic aneurysm, especially when repair is emergent. According to Laird & Ruppert (2011), the incidence of acute mesenteric ischemia in elective repair is 5%-9%, whereas with emergent repair the incidence increases to 15%-27%. The ischemia is a result of a decrease or cessation of blood flow to the mesenteric arteries either by shock states (rupture), Running head: COMPLICATIONS OF VASCULAR SURGERY 9 thrombus, or partial occlusion such as what happens with abdominal compartment syndrome. In the alert patient, the nurse will note an increase in abdominal pain with and without palpation, possibly severe. Other clinical signs and symptoms include bloody stool, increased lactate levels, acidosis, and sloughing of the mucosal layers of the intestines. These patients need to be taken back to the operating suite for repair and damage control. The treatment for patients with acute mesenteric ischemia typically includes a left colectomy as the left colon is affected in 75% of patients presenting with this complication (Laird & Ruppert 2011). Regardless of the area of ischemia, the treatment involves resection of the affected area with a resultant fecal collection appliance. Other nursing interventions include keeping the patient strictly NPO to facilitate bowel rest, fluid replacement, and antibiotic therapy. In conclusion, as the population continues to age and immerse themselves in behaviors that lead to increased risk of aortic aneurysm, nurses must have the knowledge to provide postoperative care to this patient population. As important as general postoperative care is, nurses must be trained to look for potential life-threatening or quality of life deteriorating consequences. Nurses need to know what population carries with it the highest risks and what risks are specific to each type of surgical intervention. Being at the bedside, nurses need to be direct with providers, giving them accurate information and looking for guidance from them and opportunities for further growth of their own knowledge base. This is perhaps one of the most important nursing interventions we can provide our patients – informed care. As nurses, especially those working in a primary postoperative setting, the focus is on identifying and responding to physiological changes and conditions. A study published by Letterstal, Eldh, Olofsson, & Forsberg (2010) focused instead on patient’s experiences of open repair of an abdominal aortic aneurysm. The data was gathered three months post-surgery and Running head: COMPLICATIONS OF VASCULAR SURGERY 10 explored, amongst other things, the patient’s experience during their hospital stay. A common theme for patients was feelings of embarrassment in needing help with hygiene, poor sleep quality, and a lack of dialogue regarding the care provided by various disciplines. The patients also noted that the healthcare providers focused almost entirely on physiological interventions and physical effects but did not address the emotional aspects of needing care, going home, and lifestyle changes. This study should lead nurses to remember to treat the whole person, not just the condition or symptoms. Nurses need to be able to communicate effectively with the patient, provide emotional support and make appropriate referrals to pastoral care or patient support groups. Running head: COMPLICATIONS OF VASCULAR SURGERY 11 References Adams, L., Malcotti, C., & Petrunak, E. (2007). Thoracoabdominal aneurysm repair: a case report. AANA Journal, 75(2), 117-121. Dolinger, C., & Strider, D. (2010). Endovascular interventions for descending thoracic aortic aneurysms: The pivotal role of the clinical nurse in postoperative care. Journal Of Vascular Nursing, 28(4), 147-153. Lee, R. (2012). Intra-abdominal hypertension and abdominal compartment syndrome: A comprehensive overview. CriticalCareNurse, 32(1), 19-30. Laird, P., & Ruppert, S. (2011). Ischemic colitis-a case study. Critical Care Nursing Quarterly, 34(2), 159164. Letterstål, A., Eldh, A., Olofsson, P., & Forsberg, C. (2010). Patients' experience of open repair of abdominal aortic aneurysm - preoperative information, hospital care and recovery. Journal Of Clinical Nursing, 19(21/22), 3112-3122. Vacca, V. (2009). Paraplegia & aortic surgery: What’s the connection? Nursing2009CriticalCare, 4(5), 2428. Welten, G., Schouten, O., Chonchol, M., Hoeks, S., Feringa, H., Bax, J., & ... Poldermans, D. (2007). Temporary worsening of renal function after aortic surgery is associated with higher long-term mortality. American Journal Of Kidney Diseases, 50(2), 219-228. Woodrow, P. (2011). Abdominal aortic aneurysms: clinical features, treatment and care. Nursing Standard, 25(50), 50-58.