Describe clinical signs and symptoms of light anesthesia

Both motor signs and sympathetic activation can indicate lighter levels of anesthesia. Motor signs in response to light anesthesia frequently precede hemodynamic changes or sympathetic activation. Specific motor signs include eyelid or eye motion, swallowing, coughing, grimacing, and movement of the extremities or head. Increased respiratory effort is caused by activity of intercostal and abdominal muscles, which are suppressed at deeper levels of anesthesia. With the use of neuromuscular...

What peripheral nerve block can be performed for surgery of the lower extremity

The first step in deciding what block is indicated for anesthesia or analgesia is appreciating the innervation of the lower extremity and the requirements of the proposed procedure. The lumbar plexus (L1-L4) gives origin to the ilioinguinal, genitofemoral, obturator, femoral, and lateral femorocutaneous nerves and mainly innervates the inguinal region and the anterior aspect of the thigh. The rest of the lower extremity is innervated by the sacral plexus. This includes the posterior aspect of...

Describe the pulmonary artery waveform

Perhaps the most noticeable change as the catheter tip enters the PA is the upstroke in diastolic pressure (Figure 26-2). Other features include a rapid upstroke, a progressive diastolic runoff, and a dicrotic notch secondary to pulmonic valve closure (Figure 26-3). Peak systole is found after the QRS complex but before the peak of the T wave. End diastole is found near the end of the QRS complex. Figure 26-2. Diastolic pressure increases as the pulmonary artery (PA) catheter tip crosses from...

What is diastolic dysfunction

Diastolic dysfunction can occur with normal LV EF in many patients. Impaired LV relaxation or compliance or both are the major characteristic features of LV diastolic dysfunction. Early diastolic filling depends on the rapidity of ventricular relaxation, characterized by an Figure 34-1. Left ventricular (LV) pressure-volume loops illustrating normal performance (loop 1), diastolic (loop 2), and systolic dysfunction (loop 3). AB, Diastolic filling BC, isovolumic contraction CD, ejection DA,...

Degenerative neurologic diseases and neuropathies

What is amyotrophic lateral sclerosis and its anesthetic considerations Also known as Lou Gehrig's disease, amyotrophic lateral sclerosis (ALS) is a disease of both upper and lower motor neurons. It usually affects men in the fourth or fifth decade of life. Patients with ALS develop progressive weakness and eventually die (from pneumonia and pulmonary failure), often in a 3- to 5-year period. Although extremities are involved first, eventually bulbar muscles become affected, increasing the risk...

Describe the functionally distinct compartments of body water using a 70kg patient for illustration

Accurate estimations are difficult because ordinarily ideal body weight (IBW) is used as a basis for calculation. Obesity is rampant in our society, making accurate estimations difficult. Figure 4-1 estimates body water compartments in a patient with an IBW of 70 kg. Compartment percent of total body weight Figure 4-1. Body water compartments in a patient with an ideal body weight of 70 kg. BV, Blood volume ECF, extracellular fluid ICF, intracellular fluid ISF, interstitial fluid.

How often does the preoperative evaluation alter care plans

It has been found that care plans were altered in 20 of all patients (including 15 of American Society of Anesthesiologists ASA class 1 and 2 patients) because of conditions identified at the preoperative evaluation. The most common conditions resulting in changes were gastric reflux, insulin-dependent diabetes mellitus, asthma, and suspected difficult airway. These findings indicate that, whenever possible, it is preferable in all patients to do the preoperative evaluation before the day of...

How does prone ventilation improve oxygenation

The primary pulmonary defect based on computed tomographic scans of supine patients with ARDS is the opacification of the gravity-dependent areas of the lung as a result of atelectasis and consolidation. Clearly alveolar flooding from formation of edema fluid is partially responsible for the atelectasis, but mechanical imbalances caused by cephalic displacement of Sustained inflation CPAP a CPAP of 30-40 cm H2O High-frequency ventilation High-frequency oscillation Use reverse Trendelenburg...

Key Points Perioperative Hepatic Dysfunction

Patients with end-stage liver disease have a hyperdynamic circulation with increased cardiac output and decreased systemic vascular resistance. 2. Although the portal vein supplies up to 75 of total hepatic blood flow, only 45 to 55 of the oxygen requirements are provided by this part of the circulation. 3. Because of the large reserve of the liver, significant impairment of physiologic function must occur before clinical signs and symptoms of hepatic failure become evident. 4. Because of...

Relative contraindications

Advanced chronic renal failure Age > 60 years Portal vein thrombosis Cholangiocarcinoma Hypoxemia with intrapulmonary right-to-left shunts Hepatitis HBsAg and HBeAg positivity HIV positivity without clinical AIDS Modified from Maddrey WC, Van Thiel DH Liver transplantation an overview, Hepatology 8 948,1988. AIDS, Acquired immunodeficiency syndrome HIV, human immunodeficiency virus. syndrome), hepatic disease may be overshadowed by the severity of the comorbid conditions. Prior abdominal...

Review hypokalemia and its causes

A serum level of less than 3.5 mEq L defines hypokalemia. Hypokalemia may be the result of total body loss of potassium (gastrointestinal and renal), transcellular shifts in potassium, or inadequate intake. Diuretics frequently cause hypokalemia, as do gastrointestinal losses and renal tubular acidosis. p-Adrenergic agonists, insulin, and alkalosis (respiratory and metabolic) shift potassium to the intracellular space. Hypokalemia is not uncommon in pregnant women receiving tocolytic therapy or...

Review the classifications of memory and awareness

The current classifications of memory include both implicit, or unconscious memory, and explicit, or conscious memory. Explicit memory refers to the conscious recollection of specific intraoperative events that took place during general anesthesia, also called anesthetic awareness. Recall can only be determined after surgery. These memories can occur with or without pain and can range from vivid recollections to vague memories. It was reported in 2008 that subjective auditory perceptions...

What are the anesthetic considerations in patients with preeclampsia

Before initiation of neuraxial anesthesia, evaluation of coagulation status is recommended. Because thrombocytopenia is the most common coagulopathy in preeclampsia, a screening platelet count is recommended. Although an arbitrary platelet count of 100,000 is often suggested, the actual platelet count safe for spinal or epidural placement is unknown. Spinal anesthesia has been controversial in patients with severe preeclampsia because of the potential risk of sudden hypotension with rapid onset...

What are the characteristics of a left bundlebranch block

In V1 there is a broad, deep S wave (or QS wave), with ST segment elevation, that may be preceded by a very narrow R wave (Figure 22-2). In lead I there is a broad R wave (sometimes notched) without a Q or S wave. Figure 22-2. Typical appearance of a left bundle-branch block in V1. In some cases a narrow R wave precedes the large monomorphic S wave. Figure 22-2. Typical appearance of a left bundle-branch block in V1. In some cases a narrow R wave precedes the large monomorphic S wave. The left...

What are the clinical risk factors for a major perioperative cardiac event

The Revised Cardiac Risk Index (Table 17-4) has six components history of ischemic heart disease, history of congestive heart failure, history of cerebrovascular disease, preoperative treatment with insulin, surgical risk, and elevated preoperative serum creatinine. The patient is assigned one point for each of these risk factors, which are then translated into percentage risks of perioperative major cardiac events such as myocardial infarction, pulmonary edema, ventricular fibrillation,...

What are the hemodynamic goals in the anesthetic management of patients with aortic insufficiency

In acute AI the goal is to achieve the lowest tolerable systemic blood pressure to increase the stroke volume and CO. Appropriate preload is necessary for maintenance of forward flow. Modest tachycardia reduces ventricular volumes and limits the time available for regurgitation. Contractility must be maintained p-adrenergic agonists may be used if necessary. Dobutamine can be ideal because it does not increase the afterload. Afterload reduction augments forward flow, but additional...

What are the most commonly used parenteral opioids for labor analgesia Which side effects are of special concern to the

Table 60-1 summarizes commonly used parenteral opioids and their side effects. In general, intravenous medications help the parturient tolerate labor pain but do not provide complete analgesia. The incidence of side effects and efficacy of analgesia are dose dependent. Maternal sedation and nausea are common. Opioids easily cross the placenta and may cause a decrease in fetal heart rate variability. In addition, intravenous opioids may cause neonatal respiratory depression and neurobehavioral...

What are the ramifications of awareness

Intraoperative awareness has a powerful association with patient dissatisfaction. Untreated pain is one such disturbing possibility. Other possibilities include the ability to hear operating personnel, sensations of weakness or paralysis, anxiety, helplessness, and fear of death. Subsequent effects can range from sleep disturbances, anxiety, and depression to posttraumatic stress disorder (PTSD). One study indicated late psychological symptoms occurred in 33 of patients with awareness. Symptoms...

What endotracheal tubes are available

Endotracheal tubes come in a multitude of sizes and shapes. They are commonly manufactured from polyvinyl chloride, with a radiopaque line from top to bottom standard-size connectors for anesthesia circuits or resuscitation bags a high-volume, low-pressure cuff and pilot balloon and a hole in the beveled, distal end (the Murphy eye). Internal diameter Figure 8-2. Schematic diagram demonstrating the head position for endotracheal intubation. A, Successful direct laryngoscopy for exposure of the...

What is considered a safe increase in intraabdominal pressure

The current recommendation for intra-abdominal pressure (IAP) during laparoscopy is less than 15 mm Hg, and most laparoscopic procedures are performed with IAPs in the 12-to 15-mm Hg range. In general IAPs less than 10 mm Hg have minimal physiologic effects. Insufflation pressures above 16 mm Hg result in undesirable physiologic changes (i.e., decreased CO, increased systemic vascular resistance SVR and decreased compliance of the lung and chest wall). At pressures greater than 20 mm Hg, renal...

What is HELLP syndrome

HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count) is a complication of preeclampsia. Patients develop a microangiopathic hemolytic anemia associated with thrombocytopenia and elevated liver enzymes. Ten to twenty percent of these patients will have normal blood pressure, making the diagnosis sometimes difficult. Although HELLP syndrome is not an indication itself for immediate cesarean delivery, delivery is the only definite treatment for preeclampsia. Patients who...

What is the most common perianesthetic neuropathy

The ulnar nerve is the most frequently injured peripheral nerve, although its incidence is still relatively infrequent. There is a distinct predilection for men older than 50 years of age, and it is not uncommon for there to be a few days' delay in presentation. Occasionally the neuropathy is bilateral. Of interest, the American Society of Anesthesiologists' (ASA) Closed Claims Analysis found that 15 of ulnar neuropathies occurred in patients who were sedated and received spinal or epidural...

What is the significance of autonomic dysfunction How might you tell if a patient has autonomic dysfunction

Patients with autonomic dysfunction tend to have severe hypotension intraoperatively. Evaluation of changes in orthostatic blood pressure and heart rate is a quick and effective way of assessing autonomic dysfunction. If the autonomic nervous system is intact, an increase in heart rate of 15 beats min and an increase of 10 mm Hg in diastolic blood pressure are expected when changing position from supine to sitting. Autonomic dysfunction is suggested whenever there is a loss of heart rate...

What is the value of measuring flowvolume loops in a patient with an anterior mediastinal mass

Injudicious anesthetic induction and paralysis in patients with an anterior mediastinal mass (e.g., lymphoma, thymoma, thyroid mass) may result in an inability to ventilate the patient and Figure 9-3. Idealized flow-volume loop. EXP, expiratory FEF50, expiratory flow at 50 of forced vital capacity FIF50, inspiratory flow at 50 of forced vital capacity FVC, forced vital capacity RV, residual volume TLC, total lung capacity. (Flow in L sec is abbreviated V.) (From Harrison RA Respiratory function...

What mechanism of action accounts for the inotropic effect of thyroid hormone

Thyroid hormone affects chronic changes in protein synthesis such as alterations of nuclear synthetic machinery, structural changes of the myosin isozyme, and increased expression of p-adrenergic receptors. In addition, more immediate augmentation of contractility results secondary to an increase in mitochondrial respiration and ATP production, enhanced function of sarcolemmal Ca-ATPase, and augmented sodium entry into myocytes. Elevated intracellular sodium levels increase intracellular...

What medications are useful in treating acute pain

The medications useful in treating acute pain are similar to those used in treating other types of pain. The World Health Organization analgesic ladder developed for treating patients with cancer pain also provides a useful approach to treating acute pain (Figure 77-2). At the lowest level (mild pain), nonopioid analgesics such as nonsteroidal antiinflammatory drugs (NSAIDs) (e.g., ibuprofen or acetaminophen) are useful. Such drugs have an analgesic ceiling above a certain dose no further...

When treating acute pain in a chronic pain patient how should the approach differ

When a chronic pain patient has suffered an injury or undergone surgery, the general rule is that the typical dose of oral opioids should be tripled for the first 1 to 2 days. In the preoperative preparation for a chronic pain patient, a one-time dose of gabapentin (900 to 1200 mg) or pregabalin (75 to 100 mg) coupled with a one-time dose of celecoxib (Celebrex) (200 mg) has been shown to improve pain control. After surgery gabapentin or pregabalin can be continued as a regular oral dose, and...

Why is it important to distinguish between polymorphic and monomorphic ventricular tachycardia

The differential diagnosis and treatment for each are somewhat different. Monomorphic VT is common in patients with structural heart disease (such as a previous Q wave myocardial infarction), but it is generally not caused by acute ischemia. Polymorphic VT may be seen in a variety of settings. Patients may have a long QT interval associated with polymorphic VT, commonly referred to as torsades de pointes. This may arise from medications, electrolyte derangements, a congenital predisposition...

A patient has a right bundlebranch block that is new compared to the ECG from 2 years ago How should I proceed

Although a RBBB can be caused by CAD (e.g., with a large anterior infarct destroying some of the conduction system in the interventricular septum), this is only true in a minority of RBBB patients. Such patients typically have a qR in V1 instead of an rSR' prime because the initial r wave is lost as a consequence of the MI. Occasionally an RBBB may be caused by congenital heart disease (such as tetralogy of Fallot), prior cardiac surgery, a cardiomyopathy, or pulmonary hypertension. History and...

Do all patients with an accessory pathway have a delta wave WPW pattern on their baseline electrocardiogram

Many accessory pathways conduct only in a retrograde fashion (from ventricle to atrium) or have very slow antegrade (atrial to ventricular) conduction. These patients may or may not have narrow-complex SVT (AVRT). In contrast, some patients have a delta wave on the baseline ECG with no clinical symptoms. In many cases these asymptomatic patients do not need pharmacologic treatment or invasive electrophysiologic testing. 26. A 25-year-old patient presenting with palpitations is noted to have...

How can anesthesiologists protect themselves from radiation exposure

Most institutions abide by the ALARA philosophy when it comes to protecting their workers radiation exposure should be kept As Low As Reasonably Achievable. There are three basic strategies to the ALARA philosophy Maximize the distance to the source Newton's inverse square law, which applies to any point source that spreads its influence in all directions (such as light, sound, gravitational field) tells us that the intensity of the radiation at a given radius is the source strength divided by...

Top 100 Secrets

These secrets are 100 of the top board alerts. They summarize the concepts, principles, and most salient details of anesthesiology. 1. Patients should take prescribed p-blockers on the day of surgery and continue them perioperatively. Because the receptors are up-regulated, withdrawal may precipitate hypertension, tachycardia, and myocardial ischemia. Clonidine should also be continued perioperatively because of concerns for rebound hypertension. 2. Under most circumstances peri-induction...

Key Points Concerns In Patients Taking Cocaine

Myocardial ischemia is not uncommon in cocaine-abusing patients, and selective p2-blockade should be avoided because it may cause vasoconstriction and worsen the ischemia. 2. Severe hypertension and tachycardia are risks during airway management unless the patient is deeply anesthetized. 3. Cocaine sensitizes the cardiovascular system to the effects of endogenous catecholamines. Ketamine and pancuronium potentiate the cardiovascular toxicity of cocaine and should be avoided. 26. What is crystal...

What is an acceptable preoperative platelet count

A normal platelet count is 150,000 to 440,000 mm3. Thrombocytopenia is defined as a count of < 150,000 mm3. Intraoperative bleeding can be severe with counts of 40,000-to 70,000 mm3, and spontaneous bleeding usually occurs at counts < 20,000 mm3. The minimal recommended platelet count before surgery is 75,000 mm3. However, qualitative differences in platelet function make it unwise to rely solely on platelet count. Thrombocytopenic patients with accelerated destruction but active production...

Review the pros and cons of induction agents in asthmatic patients

Intravenous induction agents used in asthmatic patients include oxybarbiturates, thiobarbiturates, ketamine, and propofol. Thiobarbiturates constrict airways in laboratory investigations and may have a loose association with clinical bronchospasm. The most common cause of bronchospasm is the stimulus of intubation, and large doses of barbiturates are required to block this effect successfully. Ketamine has well-known bronchodilatory effects secondary to the release of endogenous catecholamines...

What is the significance of portal pulmonary hypertension How are these patients managed in the pretransplant period

In contrast to mosttransplant recipients, portal pulmonary hypertension (PPHTN) patients have an increased risk of death because of right ventricular failure in the peritransplantation period. Physicians are uncertain which PPHTN patients may undergo transplantation because there are no patient characteristics that clearly predict outcome. Patients with moderate to severe PPHTN should not be considered candidates until they undergo a trial of vasodilator therapy. The cause of pulmonary...

Diabetes mellitus

Slover, MD, and Robin Slover, MD 1. Describe the principal types of diabetes mellitus. Type 1 diabetes mellitus An autoimmune disorder in which destruction of the pancreatic islet cells results in the inability to produce insulin. Onset is more common in children and young adults. Type 2 diabetes mellitus A disorder in the body's ability to use insulin. Early in the course of the disease the patient may be able to make sufficient insulin, but cell-receptor impairment results in...

A 3yearold child presents for an elective tonsillectomy His mother reports that for the past 3 days he has had a runny

Viral upper respiratory infection (URI) alters the quality and quantity of airway secretions and increases airway reflexes to mechanical, chemical, or irritant stimulation. Some clinical studies have shown associated intraoperative and postoperative bronchospasm, laryngospasm, and hypoxia. There is evidence that the risk of pulmonary complications may remain high for at least 2 weeks and possibly 6 to 7 weeks after a URI. Infants have a greater risk than older children, and intubation probably...

How long before surgery must a patient quit smoking to realize any health benefits

All patients who smoke should understand that smoking cessation even immediately before surgery has profound, measurable health benefits. Nicotine is a stimulant and has a half-life of only 1 to 2 hours its adverse effects on systolic blood pressure and heart rate can be seen after only 12 hours of smoking cessation. Carbon monoxide (CO), which diminishes oxygen-carrying capacity, has a half-life of only 4 hours. Diminished levels of nicotine and CO were likely behind the outcome of a study...

What are the causes of intraoperative wheezing and the correct responses to asthmatic patients with acute bronchospasm

Causes include airway secretions, foreign body, pulmonary edema (cardiac asthma), obstructed endotracheal tube, endotracheal tube at the carina or down a main-stem bronchus, allergic or anaphylactic response to drugs, and asthma. A number of medications cause wheezing in asthmatic patients, including p-blockers, muscle relaxants, and aspirin. After carefully checking the endotracheal tube and listening for bilateral breath sounds, increase the inspired oxygen to 100 and deepen the anesthetic if...

Alcohol and substance abuse

How is alcohol absorbed and metabolized Alcohol is absorbed across the gastrointestinal mucosa, more so in the small intestine than in the stomach. The volume of distribution (Vd) of alcohol is that of body water. Alcohol easily crosses the blood-brain barrier. Arterial blood levels of alcohol correlate well with concentrations in lung alveoli, thus the basis of the breathalyzer test used by law-enforcement officers. Alcohol is metabolized primarily in the liver. Most consumed alcohol is...

Describe the lithotomy position and its common complications

Common Positions For Anesthesia

The patient's hips and knees are flexed, and the patient's feet are placed in stirrups to gain ready access to the genitalia and perineum. The range of flexion may be modest low lithotomy or extreme high lithotomy . The feet may be suspended on vertical structures known as candy canes or in boots, or the knees may be supported with crutches. With elevation of the legs, pressure is taken off the lower back, and blood is translocated from the lower extremities to the central compartments....

Explain the gate theory of pain

In 1965 Melzack and Wall proposed that the substantia gelatinosa in the spinal cord was the primary gate in the transmission of noxious and nonnoxious stimulus to the central nervous system. The pain gate is opened by information coming from slow unmyelinated C fibers and closed by the impulses from faster myelinated fibers such as A-p. Since pain is transmitted by slow A-S and C fibers, they reason that, by activating faster fibers such as the ones that transmit proprioception, the gate will...