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...

Of Elevated

Hypotonic or glucose-containing intravascular fluid 4. High concentrations of inhalation agents 20. What are the mechanisms behind traumatic brain injury The damage to the brain after traumatic injury can be divided into two categories 1. Damage from the primary mechanism of injury 2. Damage from secondary insults (hypotension, hypoxia) The primary mechanism (e.g., motor vehicle crash, gunshot) can result in focal or global damage to the brain tissue. Focal injuries are primarily caused by...

Other Motor Diseases

MH is a hypermetabolic disorder that presents in the perioperative period after exposure to inhalational agents or succinylcholine. 2. Early recognition is critical and treatment is complex and multifaceted, requiring the assistance of other experienced personnel. 3. The sine qua non of MH is an unexplained rise in end-tidal carbon dioxide in a patient with unexplained tachycardia. A temperature rise is a late feature. 4. Patients with a history of MH or who are MH susceptible must receive...

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...

Renal function and anesthesia

The kidneys are paired organs lying retroperitoneally against the posterior abdominal wall. Although their combined weight is only 300 g (about 0.5 of total body weight), they receive 20 to 25 of the total cardiac output. The renal arteries are branches of the aorta, originating below the superior mesenteric artery. The renal veins drain into the inferior vena cava. Nerve supply is abundant sympathetic constrictor fibers are distributed via celiac and renal...

Should neuromuscular blockade be used to facilitate mechanical ventilation

Neuromuscular blocking agents (NMBAs) are commonly used to facilitate MV during ARDS but, despite wide acceptance, there are few data and as yet no consensus available for when these agents should be used. Gainnier and associates (2004) were the first to report the effects of a 48-hour NMBA infusion on gas exchange in patients with early ARDS. All patients were ventilated according to the ARDSNet protocol. Significant improvements in oxygenation and ability to lower PEEP occurred in the NMBA...

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 features of informed consent

Informed consent involves the communication of the anesthetic plan in terms the patient understands and covers everything from premedication and preoperative procedures to intraoperative management and postprocedural care (e.g., management of pain, nausea, and vomiting). The alternatives, potential complications, and risks vs. benefits are discussed, and the patient's questions are answered. Preoperative evaluation and informed consent establish a trusting doctor-patient relationship that...

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 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 rapidsequence induction Which patients are best managed in this fashion

It is easiest to appreciate the distinctions of rapid-sequence induction (RSI) if an induction under nonrapid-sequence conditions is understood. Ordinarily the patient has fasted for at least 6 to 8 hours and is not at risk for pulmonary aspiration of gastric contents. The patient is preoxygenated, and an anesthetic induction agent is administered. Once it is established that the patient can be mask-ventilated satisfactorily, a muscle relaxant is given. The patient is then mask-ventilated until...

What is the best way to treat inhalation injury

Oxygen should be provided as necessary to ensure adequate oxygenation. Bronchospasm usually responds to p-agonists. Patients with smoke inhalation can require greater fluid resuscitation than other patients with burns. Pulmonary toilet may be important if there is excessive carbonaceous material in the lungs. Intubation or tracheotomy may be necessary if there is significant upper airway compromise. Patients with heat and smoke injury plus extensive face and...

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 most common replacement fluid used in children

A BSS such as lactated Ringer's (LR) with glucose (D5LR) or without glucose (LR) is recommended. Hypoglycemia may occur in healthy children undergoing minimally invasive procedures if glucose-containing fluids are not used, but administration of 5 glucose-containing solutions results in hyperglycemia in the majority of children. Perhaps fluid containing 1 or 2.5 glucose is best. Others still use 5 glucose solutions for maintenance but recommend nonglucose-containing BSS for third space or blood...

When should a child be premedicated Which drugs are commonly used

Children may have fear and anxiety when they are separated from their parents and during anesthetic induction. Children who are 2 to 6 years old who have had previous surgery or no preoperative tour and education or who fail to interact positively with health care providers in the preoperative area should be premedicated. Children who are anxious during induction may suffer from negative postoperative behavioral changes. Children who receive premedication with midazolam have fewer negative...

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...

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....