Page 1535 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

1054 PART 10: The Surgical Patient

TABLE 111-1 Considerations for Preoperative Anesthesia Assessment TABLE 111-2 ASA Classification
1. Request for consultation—either patient- or surgeon-initiated request for preoperative 1. Healthy
anesthetic care discussion 2. Illness that does not impede activities of daily living
2. Anesthetic considerations
• Patient has personal history of anesthesia-related serious adverse event 3. Illness that impedes activities of daily living
• Patient or family history of malignant hyperthermia 4. Illness that represents a constant threat to life
• Anticipated or past history of difficult intubation
3. Surgical considerations 5. Not expected to survive 24 h (with or without surgery)
• Major cardiac, vascular, or intrathoracic procedures 6. The patient declared dead for purposes of organ donation
• Cervical spinal procedures The suffix “E” denotes emergency surgery
• Implantable cardiac defibrillator procedures
• Percutaneous procedures to repair aneurysms (aortic or cerebral) or cardiac valves
4. Patient considerations patients is thought to be better than 1:50,000. The risk rises acutely for
General ASA 4 but is not 100% for ASA 5! Additionally, statistics are made more
3
• Gravid patient for nonobstetric surgery difficult to interpret as the score is assigned by a clinician who is free
• Poor functional capacity (unable to walk one block or climb one flight of stairs) to interpret “constant threat to life.” A patient critically dependent on
• Recent deterioration of chronic medical problem dialysis may logically be called ASA 4 but such patients have competed
• Admission to hospital in last 2 months for acute (or exacerbation of a chronic medical) in triathlons. Therefore, clinicians should not depend entirely on such
4
problem
• Unusual or complicated medical problem scales for risk assessment but critically assess the individual.
Cardiovascular
• Coronary artery disease (history of angina or myocardial infarction) ASSESSMENT OF PERIOPERATIVE CNS RISK
• Congestive heart failure
• Valvular heart disease or other structural cardiac abnormality (eg, congenital VSD) Delirium is a common postoperative complication. As discussed in
• History of CABG/PTCA, valvular repair, structural cardiac repair, or cardiac defibrillator Chap. 82, patients cared for in critical care areas can suffer rates nearing
implantation 80%. Delirium in elderly postoperative patients is thought to have a 50%
5
• Diffuse vasculopathy occurrence. Longitudinal studies have demonstrated long-term cogni-
• Diastolic blood pressure >100 mm Hg tive dysfunction in patients who have suffered delirium as inpatients. 6
• Symptomatic arrhythmia, particularly new or undiagnosed atrial fibrillation The risk factors for delirium are numerous and include the trauma of
Respiratory surgery and anesthesia (Table 111-3). Strangely enough, patients who
• Asthma or COPD have received regional anesthetics, thus likely exposed to less opiates,
• Obstructive sleep apnea (including symptomatic patients who have not had a sleep study) have the same rate of delirium as similar patients who have undergone
• Pulmonary hypertension general anesthetics. Other factors common to our aging population such
7
• Other serious lung diseases, for example, cystic fibrosis, sarcoidosis, idiopathic pulmonary as structural (stroke, brain injury) and nonstructural (psychiatric) brain
fibrosis disease increase the risk for delirium. Knowing that a patient may suffer
• Upper or lower airway tumor or obstructions postoperative delirium allows treatment to commence immediately.
• Any chronic respiratory disease requiring home oxygen, ventilatory assistance, or monitoring Postoperative pain is a very important risk factor for the development
Neurologic of delirium. Patients may enter a terrible feedback loop of suffering from
• Neuromuscular diseases, for example, myasthenia gravis, muscular dystrophy, myotonic delirium only to have opiates removed from their postoperative regime
dystrophy to then experience more pain and more delirium! The phenomenon
• Quadri-, hemi-, or paraplegia of patients receiving inadequate pain control is even more important
• Cervical spine instability, myelopathy, or radiculopathy in the critical care units where reliance on propofol sedation without
• Other serious neurologic disease, for example, poorly controlled seizures, cerebral palsy
Metabolic concomitant analgesia gives rise to a calm appearing patient. Given that
• Morbid obesity—>1.5× ideal body weight or BMI >40 many ICUs do not have a formal sedation and analgesia protocol, which
• Diabetics on insulin
• Diabetics on oral agents only if comorbidities are present
Hematologic TABLE 111-3 Partial List of Risk Factors for Delirium
• Anemia Patient factors:
• Sickle cell disease
• Coagulopathy, for example, hemophilia, von Willebrand disease, thrombocytopenias Advanced age
• Patients on anticoagulant (warfarin or low-molecular-weight heparin) therapy or Dementia
prophylaxis CNS and psychiatric disease
Other
• Severe latex allergy Severe medical disease
• Significant renal dysfunction or dialysis dependent Drug or alcohol addiction
• HIV Vision or hearing loss
• Chronic hepatitis or known hepatic dysfunction
• History of ongoing drug or alcohol abuse Postoperative factors:
Anesthesia
Surgery/trauma
Pain
The American Society of Anesthesiologists (ASA) physical status clas-
sification was created with a similar goal (Table 111-2) and is still com- Severe illness
monly used as an index of surgical risk. The Dripps-American Surgical Sleep deprivation /noisy environment
1
Association classification is essentially identical. Not surprisingly, for Polypharmacy
2
a nonparametric scale, morbidity and mortality do not rise regularly
with increasing score. The risk for anesthesia and surgery for ASA 1-2 Psychotropic Rx (including benzodiazepines and opiates)

section10.indd 1054 1/20/2015 9:19:32 AM