Chapter 11 – Preoperative Care in Emergency Surgery




Chapter 11 Preoperative Care in Emergency Surgery


Andrea Falvo , Valeria Frisenda , Cesare Gregoretti and Luca Brazzi




Be prepared.


Sir Robert Baden-Powell



Introduction


Surgical emergencies in the elderly concern mainly trauma, intra-abdominal and vascular surgery. Abdominal pain constitutes 10–15% of all complaints and the unspecific nature of initial symptoms often makes accurate diagnosis difficult. Radiological imaging is often employed in aiding diagnosis and delay in performing these investigations can impact on surgical outcomes. Delays can be attributed to unstable hemodynamic conditions, delayed presentation of the illness, lack of physical signs at first presentation and inability to obtain proper history.


The overall morbidity seems to be reduced when surgery is performed within the first 24–48 hours, whilst delays are associated with complications and higher mortality rates (Ryan et al. 2015).


Emergency surgery is more frequent in the elderly than in younger patients and emergency cases have higher morbidity and mortality compared to elective surgery. The increased prevalence of age-related disease and comorbidity contrasts with the ability to recover from the physiological challenges of surgery and anesthesia and, especially in the setting of emergency surgery, there may not be time for complete evaluation and correction of risk factors.


Clear understanding of the importance of identifying priorities, adequate organization in care delivery and a team approach is the most valid key for ensuring the best achievable outcome.



Care Priorities in Geriatric Emergencies


Pre-existing conditions and/or severe anatomical injuries increase the risk of poor outcome in elderly patients. Triage is defined as the identification of the severity of injury, the degree of physiological derangement and allocation of treatment according to priorities meant to increase the maximum number of survivors.


A priority-wise approach should be employed when dealing with geriatric emergencies in order to correct all life-threatening conditions and give immediate organ support when required.



Airway Control


During the classic Airway, Breathing, Circulation, Disability, Exposure (ABCDE) assessment it is important to bear in mind the increased risk of aspiration as elderly patients have reduced protective airway reflexes secondary to muscular and neural degenerative changes.



Correction of Hypovolemia


Hypovolemia is very common in elderly patients presented for emergency surgery, even in the absence of bleeding or shock (Table 11.1). The tolerance to hypovolemia is poor in this specific population mainly because of the decreased β-receptor responsiveness and inadequate increase of heart rate in response to low cardiac output.




Table 11.1 Surrogate markers or findings of intravascular volume status











































Markers Signs of hypovolemia
Mean arterial pressure (cerebral and abdominal perfusion pressure) Reduced
Urinary output Oligo/anuria
Mental status Altered, confused, agitation, delirium
Capillary refill time >3 seconds
Skin Mottling, cool peripheries, cold knee (Marik’s sign), dry
Mucosa Dry
Blood lactate >2 mmol/l
Arterial pH, BE and HCO3 Metabolic acidosis
Mixed venous oxygen saturation (SmvO2) and central venous oxygen saturation (ScvO2) Reduced
Hematocrit Increased from baseline
Creatinine >20 mg/dl

On the other hand, rapid correction of hypovolemia in the absence of proper monitoring may easily lead to overloading, pulmonary edema and heart failure.


The presence of a working, well-secured access to the circulation is imperative. Central vascular access is seldom indicated in the prehospital setting; an intraosseous approach is recommended in all cases in which a peripheral intravenous cannulation fails.


The perioperative administration of fluids, with or without vasoactive drugs, targeted to increase global blood flow, seems to reduce postoperative complications and length of stay, even if it doesn’t reduce mortality (Grocott et al. 2013).


Electrolyte imbalances should be promptly corrected in order to prevent malignant tachy/brady-arrhythmias which would be detrimental in an already preload-dependent heart (Orliaguet et al. 2001).


There is no clear evidence regarding blood transfusion threshold. Some studies found no difference in terms of mortality in patients with hemoglobin levels >8 g/dl, whilst others suggested higher hemoglobin levels for patients with known cardiac disease (Spahn et al. 2015). Observational data show higher mortality after major non-cardiac surgery in patients aged >65 years if they have a preoperative hematocrit <24%, but lower mortality if it is 30–36% (Spahn et al. 2015).



Prevention of Hypothermia


Hypothermia is known to be associated with a poor prognosis, with mortality as high as 34% (Pedley et al. 2002). The age-related physiological changes alter vasoconstriction and heat production; shivering is less effective and induced at lower temperatures compared to younger subjects (Sessler 2008).


The best management of hypothermia is still controversial, as rapid warming can lead to vasodilatation and reduction in blood pressure (Parr and Alabdi 2004). Moreover, given the high incidence of cardiovascular disease, rapid infusion of warm fluids can increase the risk of precipitating fluid overload. Anesthesia itself can worsen the hypothermia. In the prehospital setting it should hence be reserved for those deeply unconscious or unable to maintain their airway as there is an increased risk of ventricular fibrillation during intubation.



Preoperative Assessment



Clinical History


Once the patient reaches the emergency department, a careful clinical examination associated with an electrocardiogram (ECG) and blood chemistry should be used. A rapid multidisciplinary approach is of paramount importance in order to have a clear plan of intervention and provide patient-specific management of existing comorbidities. Early senior decision-making is also essential to provide the appropriate palliative care for people who are dying and would not benefit from invasive management (RCS 2011).


Risk assessment is part of preoperative assessment, even in emergency situations. High-risk patients identified as those with predicted mortality >10% should receive surgery under the direct supervision of senior consultants in anesthesia and surgery. In addition, patients aged >60 years and with shock from any cause have an increased mortality rate of 10% (Nasa et al. 2012).


POSSUM score (Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity) is a risk assessment scale that is popular in the United Kingdom and takes into consideration the physiological impact of the surgical procedure, taking into account whether the procedure is emergent or elective, including age as an independent risk factor (Scott et al. 2014).


The different aspects that should be taken into consideration by the treating physicians are: organ-specific morbidity, postoperative cognitive disorders (POCDs), postoperative delirium (POD) and malnutrition.



Organ-specific Morbidity


An assessment of baseline physical status, functional reserve of organ systems, comorbid conditions and surgery-specific risk should be undertaken. Incidence of ischemic heart and valve disease increases with age and is associated with increased morbidity and mortality. ECG and echocardiography are useful and cheap tools for a quick assessment. Interventions should aim to reduce oxygen uptake (the total volume of oxygen consumed by the body in 1 minute) and improve oxygen delivery. Autonomic dysfunction should be investigated to identify the risk of a poor response to hypovolemia, reduced gut motility and disordered temperature homeostasis. In patients treated for hypertension, ischemic heart disease and heart failure, daily drugs should not be discontinued because withdrawal may be harmful. ACE inhibitors, on the other hand, should not be administered on the day of surgery because they can lead to difficulty in maintaining blood pressure during the perioperative period.


Anticoagulants are often used in this specific population. Warfarin reversal with oral or intravenous vitamin K combined with temporary discontinuation of the drug is recommended if it will allow earlier surgery (Watson et al. 2001). There are limited and unclear indications for transfusing fresh-frozen plasma and cryoprecipitate, unless there is a contraindication to using vitamin K (Szczepiorkowski and Dunbar 2013).


Antiplatelet therapy should be stopped for a minimum of five days before elective surgery. In an emergency setting it is recommended not to delay surgery and to transfuse platelets in the event of excessive surgical bleeding (Douketis et al. 2008).


History of smoking, active chest disease and recent chest infection or recent hospital admissions with pulmonary symptoms suggest the need for further investigation, since smoking and chronic obstructive pulmonary diseases (COPD) are together predictors of poor outcome.


Renal insufficiency increases surgical risk. Prerenal azotemia can often be corrected with intravenous fluids, whilst early renal replacement therapy should be taken into consideration when appropriate. Attention should be paid to dosages of renally excreted drugs, which must be adjusted for reduced creatinine clearance.


Poorly controlled diabetes increases the risk of perioperative infection, therefore glucose should be monitored closely and drugs administered promptly.



POD and POCDs


The process for identifying and reducing the risk of both POD and POCDs should begin at preoperative assessment. Increased incidence of postoperative cognitive complications (see Chapter 14) is related to: age, dementia or cognitive impairment, depression, history of delirium, severe illness or hip fracture, poly-pharmacy, malnutrition and dehydration, functional dependency and sensory impairment. Rapid recognition and intervention throughout the multidisciplinary team can reduce prevalence, severity and duration of these negative outcomes (ESA 2017).



Malnutrition


Malnutrition is a strong predictor of postoperative complications and mortality and is highly prevalent in the elderly population. Various nutrition indices, such as Body Mass Index (BMI), Malnutrition Universal Screening Tool (MUST) and Mini-Nutritonal Assessment (MNA) can be used (Kondrup et al. 2003, Stratton et al. 2004, Kyle et al. 2006). Oral nutrition along with nutrition supplements is the most effective intervention to improve nutritional status, but close monitoring is recommended to monitor for signs of emerging refeeding syndrome (see Chapter 13).



Vascular Emergencies



Abdominal Aortic Aneurysm (AAA) Rupture


AAA rupture represents a great challenge and has a very high mortality rate due to major blood loss and consequent end-organ hypoperfusion. Overall mortality remains at 75%, with half of the patients never reaching the hospital and 50% of the other half dying in the admitting hospital (Stoneham et al. 2014).


Endovascular aneurysm repair (EVAR) has become increasingly available in many European countries. It requires considerable expertise and logistics, but may offer significant survival benefits (Biancari et al. 2011, Mehta et al. 2013). Open repair of AAA typically requires general anesthesia, while EVAR can be performed under general, regional or local anesthesia.


Cautious initial resuscitation is a key point, with a target systolic blood pressure lower than 100 mmHg, provided that the patient can maintain consciousness. Adequate vascular accesses are always required and patient should be prepared and draped while awake with anesthesia induction postponed till surgeons are scrubbed and ready for incision. Minimal monitoring (blood pressure, pulse oximetry and ECG) should suffice, at least in the initial phases. Acid-base balance, hemoglobin concentration and coagulation status (thrombo-elastography throughout) evaluation systems (points of care) should always be present to facilitate appropriate clinical decisions about fluid therapy and administration of blood products.



Acute Limb Ischemia


Acute limb ischemia is a surgical emergency that often limits the extent of preoperative evaluation and optimization that can be performed. The increased risk of rhabdomyolysis associated with acute renal injury should always be taken into account in all cases of compartmental syndromes requiring fasciotomy. General anesthesia is often required since the anticoagulation treatment commonly applied immediately after diagnosis may preclude regional anesthesia.



Trauma Emergencies


Falls are the main trauma emergencies and the great majority of the research in the field comes from hip fracture studies. Hip fractures are associated with profound consequences for the elderly, with high rates of mortality and morbidity; healthier patients should hence be taken to the operating theatre as soon as possible, whilst sicker patients should not undergo surgery prior to medical optimization. Surgery is, however, always recommended within 24–48 hours in the majority of patients. In some countries dedicated trauma lists and the presence of trauma coordinator trusts are beginning to show the ability to deliver same-day surgery for these patients, with additional survival benefit at 30 days after surgery (Bretherton and Parker 2015, Ryan et al. 2015).


Preoperative optimization includes clinical assessment, prevention and management of pressure sores and immediate pain relief (Pergolizzi et al. 2008). This can be obtained with acetaminophen as the initial drug, even if opioids and nerve blocks are suggested by continuous assessment. Non-steroidal anti-inflammatory drugs are best avoided in the elderly because of the increased risk of bleeding and potential kidney damage.


Since at hospital admission these patients are often anemic, due to hemorrhage, and hypovolemic, due to dehydration and preoperative fasting, an echocardiogram is always recommended, especially for patients with a history of angina or decreased left ventricular function.


Early geriatric intervention during the acute phase of hip fracture in the elderly has been reported to reduce in-hospital mortality and medical complications (Tierney and Vallis 1999, SIGN 2009).



Emergency Intra-abdominal Surgery


The majority of patients undergoing emergency laparotomy are over the age of 70. The most common indications are bowel-related pathologies such as obstruction, perforation, peritonitis, bowel ischemia and, less frequently, abdominal abscess, sepsis from another source, hemorrhage and colitis.


Delays in surgery are associated with a poorer outcome, with an increased mortality rate from 6 to 45% when surgery takes place more than 24 hours after admission.


Age alone independently represents a risk factor for emergency laparotomy with an increase of 5% per decade from a baseline of approximately 5% in patients in their 50s, to a mortality rate for patients aged 70 or more years of 20% (RCA 2015, Green et al. 2013).


Preoperative assessment and optimization should include: (1) a prompt review by consultant surgeon and anesthetist; whenever possible and feasible in the available time, a geriatric consultation should be added; (2) an accurate risk assessment; (3) early antibiotics, especially if sepsis is present; (4) computed tomography and other appropriate imaging to clearly define pathology.


Endoscopic stenting may allow patient stabilization in less emergent cases and a loop ileostomy or colostomy may be considered as a palliative procedure to relieve symptoms at least in some patients.



Conclusions


Improving outcomes in emergency surgery for the geriatric population is a complex task, but has great clinical and healthcare system implications. The key to better outcomes and decreased mortality and morbidity is the understanding of the physiological changes seen in the aging process and the response to medical treatment and surgical intervention, in order to tailor an anesthetic plan that will optimize the patient’s recovery.

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Jan 16, 2021 | Posted by in ANESTHESIA | Comments Off on Chapter 11 – Preoperative Care in Emergency Surgery
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