By G. Potros. Bethany Lutheran College. 2019.
However lopressor 100mg line, only four stereoisomers are found in our blood discount 12.5mg lopressor fast delivery, all of them variants of alpha-tocopherol lopressor 50 mg overnight delivery. The vitamin is also found in nuts discount lopressor 100mg with mastercard, wheat germ, whole-grain products, and mustard greens. Accordingly, this limit should be exceeded only when there is a need to manage a specific disorder (e. Symptoms of deficiency include ataxia, sensory neuropathy, areflexia, and muscle hypertrophy. Potential Benefits Vitamin E has a role in protecting red blood cells from hemolysis. The higher dose associated with halting macular degeneration carries substantial risk, as detailed in the discussion that follows. Potential Risks High-dose vitamin E appears to increase the risk for hemorrhagic stroke by inhibiting platelet aggregation. These results are consistent with the theory that high doses of antioxidants may cause cancer or accelerate cancer progression. Studies have also linked high-dose vitamin E therapy with an increased risk for death, especially in older people. Finally, high-dose vitamin E (in combination with vitamin C) can blunt the beneficial effects of exercise on insulin sensitivity. Forms and Sources of Vitamin K Vitamin K occurs in nature in two forms: (1) vitamin K, or phytonadione1 (phylloquinone), and (2) vitamin K. Two other forms2 —vitamin K 4 (menadiol) and vitamin K 3 (menadione)—are produced synthetically. At this time, phytonadione is the only form of vitamin K available for therapeutic use. For most individuals, vitamin K requirements are readily met through dietary sources and through vitamin K synthesized by intestinal bacteria. Because bacterial colonization of the gut is not complete until several days after birth, levels of vitamin K may be low in newborns. Pharmacokinetics Intestinal absorption of the natural forms of vitamin K (phytonadione and vitamin K ) is adequate only in the presence of bile salts. Because the natural forms of vitamin K require bile salts for their uptake, any condition that decreases availability of these salts (e. Malabsorption syndromes (sprue, celiac disease, cystic fibrosis of the pancreas) can also decrease vitamin K uptake. Other potential causes of impaired absorption are ulcerative colitis, regional enteritis, and surgical resection of the intestine. Disruption of intestinal flora may result in deficiency by eliminating vitamin K–synthesizing bacteria. In infants, diarrhea may cause bacterial losses sufficient to result in deficiency. Consequently, to rapidly elevate prothrombin levels and reduce the risk for neonatal hemorrhage, the American Academy of Pediatrics and the Centers for Disease Control and Prevention recommend that all infants receive a single injection of phytonadione (vitamin K ) immediately after delivery. This previously routine prophylactic1 intervention has recently been challenged by parents who believe that the risks outweigh benefits. Subsequent to increases in parents declining prophylaxis, there has been an increase in life-threatening vitamin K deficiency bleeding in recent years. As discussed in Chapter 44, the anticoagulant warfarin acts as an antagonist of vitamin K and thereby decreases synthesis of vitamin K–dependent clotting factors. As a result, warfarin produces a state that is functionally equivalent to vitamin K deficiency. If the dosage of warfarin is excessive, hemorrhage can occur secondary to lack of prothrombin. Hyperbilirubinemia When administered parenterally to newborns, vitamin K derivatives can elevate plasma levels of bilirubin, thereby posing a risk for kernicterus. The incidence of hyperbilirubinemia is greater in premature infants than in full-term infants. Although all forms of vitamin K can raise bilirubin levels, the risk is higher with menadione and menadiol than with phytonadione. Therapeutic Uses and Dosage Vitamin K has two major applications: (1) correction or prevention of hypoprothrombinemia and bleeding caused by vitamin K deficiency and (2) control of hemorrhage caused by warfarin. Vitamin K Replacement As discussed, vitamin K deficiency can result from impaired absorption and from insufficient synthesis of vitamin K by intestinal flora. For children and adults, the usual dosage for correction of vitamin K deficiency ranges between 5 and 15 mg/day. To prevent hemorrhagic disease in neonates, it is recommended that all newborns be given an injection of phytonadione (0. Warfarin Antidote Vitamin K reverses hypoprothrombinemia and bleeding caused by excessive dosing with warfarin, an oral anticoagulant. Preparations and Routes of Administration Phytonadione (vitamin K ) is available in 5-mg tablets, marketed as Mephyton,1 and in parenteral formulations (2 and 10 mg/mL) sold generically. For example, this might be indicated in management of life- threatening bleeding due to vitamin K antagonists (e. Water-Soluble Vitamins The group of water-soluble vitamins consists of vitamin C and members of the vitamin B complex: thiamine, riboflavin, niacin, pyridoxine, pantothenic acid, biotin, folic acid, and cyanocobalamin. They are grouped together because they were first isolated from the same sources (yeast and liver). Vitamin C is not found in the same foods as the B vitamins and hence is classified by itself. Two compounds—pangamic acid and laetrile—have been falsely promoted as B vitamins. Vitamin C (Ascorbic Acid) Actions Vitamin C participates in multiple biochemical reactions. Among these are synthesis of adrenal steroids, conversion of folic acid to folinic acid, and regulation of the respiratory cycle in mitochondria. At the tissue level, vitamin C is required for production of collagen and other compounds that comprise the intercellular matrix that binds cells together. In addition, vitamin C has antioxidant activity and facilitates absorption of dietary iron. Sources The main dietary sources of ascorbic acid are citrus fruits and juices, tomatoes, potatoes, strawberries, melons, spinach, and broccoli. Deficiency Deficiency of vitamin C can lead to scurvy, a disease rarely seen in the United States. Symptoms include faulty bone and tooth development, loosening of the teeth, gingivitis, bleeding gums, poor wound healing, hemorrhage into muscles and joints, and ecchymoses (skin discoloration caused by leakage of blood into subcutaneous tissues). Many of these symptoms result from disruption of the intercellular matrix of capillaries and other tissues.
A smaller lesser sac or omental bursa is found posterior to the liver and stomach cheap lopressor 12.5 mg without a prescription. It communicates with the greater sac via the omental foramen (epiploic foramen of Winslow) buy lopressor 100 mg amex. The peritoneal cavity of the male is closed lopressor 12.5mg lowest price, but that of the female is open to the outside via the uterine tubes order lopressor 12.5 mg with visa, uterus, and vagina. The parietal peritoneum of the central underside of the diaphragm (derived from the septum transversum) receives its sensory innervation from the phrenic nerve (C3−C5). Innervation of the peritoneum on the underside of the diaphragm’s periphery is pro- vided by spinal nerves T6 through T12. These somatic nerves providing sensory innervation to the parietal peritoneum are essen- tially sensitive to pain, touch, temperature, and pressure. This latter sensation is the basis of rebound tenderness from an already irritated peritoneum. Sensory innervation from the visceral peritoneum covering most of the abdomino- pelvic organs, as well as their mesenteries, are not sensitive to touch, temperature, or pressure, but are sensitive to ischemia, stretching, or tearing, such as from a swollen or distended organ. Referred pain means the sensation of pain at a site different from its original source. Pain sensation originating from a gastrointestinal organ is often perceived at or near the midline. The clinically important referred pain involves both the visceral and somatic sensory nerves. For example, the visceral afferent fibers from the stomach travel to the spinal cord via the greater splanchnic nerves to reach the T5 through T9 levels of the spinal cord. Pain from the stomach is often perceived initially and somewhat vaguely at the epigastric midline, which, in turn, is supplied by spinal nerves T5 through T9. Visceral afferent fibers from the appendix enter the spinal cord at approximately the T10 level, and pain from a distended appendix is initially perceived at the periumbilical region which is typically supplied by the T10 spinal nerve. If the organ is inflamed and becomes distended, as is often the case, the adjacent parietal peritoneum may also became irritated. In such instances, the ini- tially vague periumbilical discomfort can shift to a well-localized, intense right lower quadrant pain from the appendix itself. This well-localized pain may be accompa- nied by muscular rigidity or “guarding,” which is a body reflex, while attempting to reduce peritoneal movement, which, in turn, may produce pain. For example, a common pathway that courses superiorly to the brain from the spinal cord may also be involved in the conscious perception of pain. The sensory impulses of the central underside of the diaphragm are sent to segments C3 through C5 of the spinal cord, from which the phrenic nerve arises. The dermatome at the level of the umbilicus is T10, and its sensory fibers are a part of the T10 spinal nerve. He states that the pain is worse when he tries to lift his arm and he has difficulty keeping his arm elevated for more than a few seconds. Additionally, he is unable to hold his arm in an abducted position and has weakness with external rotation. Following injection of lidocaine in the joint, his pain disappears, but the weakness continues. He has pain with abduction in addition to weakness with external rotation on examination. Injection of a local anesthetic relieves his pain but not help the weakness that he has been experiencing. Although some patients may be asymptomatic, common complaints include pain and weakness with abduction. The rotator cuff may be torn acutely, such as with trauma, or it may be a chronic issue, with both degeneration secondary to age and repetitive stress con- tributing. The rotator cuff stabilizes the glenohumeral joint and facilitates various arm movements. The supraspinatus contributes to abduction of the arm, especially early abduction. Lidocaine injection is helpful for diagnosis as it distinguishes rotator cuff tendinopathy from a tear. Lidocaine relieves pain in both injuries, but will improve strength in only tendinopathy. Four of the intrinsic shoulder muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) are referred to as rotator cuff muscles (see Table 57-1) because their muscle fibers and tendons surround the capsule of the shoulder joint to form the musculotendinous rotator cuff (see Figure 57-1). Supraspinous tendon Deltoid muscle Coracoacromial (cut) ligament Acromion Clavicle Coracoclavicular ligament Infraspinous tendon Coracoid Superior Coracohumeral glenohumeral ligament ligament Tendon of long Teres minor head of biceps Glenoid cavity Subscapularis muscle Glenoid labrum Articular capsule Long head of triceps Figure 57-1. Between the tendons of the rotator cuff muscles and the joint capsule are the bursae, which contain synovial fluid to reduce friction during muscle contractions. Lesions or degeneration of the rotator cuff and related bursae are common causes of pain in the shoulder area. A radiograph of the shoulder indicates that the supraspinatus ten- don is calcified. The patient is noted to have numbness of the right lateral upper arm and also inability to abduct his arm. This patient likely has rotator cuff syndrome due to repetitive wear- and-tear of the rotator cuff muscles. The rotator cuff consists of the supraspi- natus, infraspinatus, teres minor, and subcapsularis muscles. This patient likely has axillary nerve injury from blunt trauma to the quad- rangular space. The quadrangular space is where the axillary nerve travels from anterior to posterior. It is bounded by the subscapularis muscle and teres minor, teres major, surgical neck of the humerus, and the long head of the triceps muscle. The suprascapular nerve innervates the supraspinatus and infraspina- tus muscles, and the subscapular nerve innervates the teres major and infra- spinatus muscles. Besides rotatory movement of the humerus in specific directions, the rota- tor cuff is an important stabilized of the shoulder. The paresthesias and weak- ness worsen when he lifts his arm over his head to perform tasks such as painting or hammering. The numbness also sometimes wakes him up at night and is worst on the volar side of his fourth and fifth fingers. He has also noticed that his right hand and fingers sometimes seem paler and colder than his left hand and fingers. He denies any history of trauma to the shoulder or arm and of any medical prob- lems. These structures run through the thoracic outlet, between the clavicle and the first rib. The brachial plexus and subclavian artery also run between the anterior and middle scalene muscles. Depending on the severity, treatment can range from stretching and physical therapy to surgery.
Mechanism of Action In normal individuals effective 100 mg lopressor, prostaglandins help protect the stomach by suppressing secretion of gastric acid buy lopressor 100mg low price, promoting secretion of bicarbonate and cytoprotective mucus buy lopressor 25 mg without prescription, and maintaining submucosal blood flow (by promoting vasodilation) lopressor 100 mg on line. Adverse Effects The most common reactions are dose-related diarrhea (13%–40%) and abdominal pain (7%–20%). B l a c k B o x Wa r n i n g : M i s o p ro s t o l i n P re g n a n c y Misoprostol is contraindicated during pregnancy. Because prostaglandins stimulate uterine contractions, use of misoprostol during pregnancy has caused partial or complete expulsion of the developing fetus. If women of childbearing age are to use misoprostol, they must (1) be able to comply with birth control measures, (2) be given oral and written warnings about the dangers of misoprostol, (3) have a negative serum pregnancy test result within 2 weeks before beginning therapy, and (4) begin therapy only on the second or third day of the next normal menstrual cycle. Beneficial Actions Antacids react with gastric acid to produce neutral salts or salts of low acidity. In addition, if treatment raises gastric pH above 5, these drugs will reduce pepsin activity as well. Antacids may also enhance mucosal protection by stimulating production of prostaglandins. With the exception of sodium bicarbonate, antacids are poorly absorbed and therefore do not alter systemic pH. Other Uses Antacids are administered before anesthesia to prevent aspiration pneumonitis. Although antacids are used widely by the general public to relieve functional symptoms (dyspepsia, heartburn, acid indigestion), there are no controlled studies that demonstrate efficacy in these conditions. Dosage and Formulations Dosage The objective of peptic ulcer therapy is to promote healing and not simply to relieve pain. Consequently, antacids should be taken on a regular schedule, not just in response to discomfort. In the usual dosing schedule, antacids are administered 7 times a day: 1 and 3 hours after each meal and at bedtime. At this pH there is inhibition of pepsin activity in addition to nearly complete (greater than 99. Antacids are inconvenient and unpleasant to ingest, making adherence difficult—especially in the absence of pain. Patients should be encouraged to take their medication as prescribed, even after symptoms are gone. Antacid tablets should be chewed thoroughly and followed with a glass of water or milk. Effects on the bowel can be minimized by combining an antacid that promotes constipation with one that promotes diarrhea. Patients should be taught to adjust the dosage of one agent or the other to normalize bowel function. Because sodium excess can exacerbate hypertension and heart failure, patients with these disorders should avoid preparations that have a high sodium content. Drug Interactions By raising gastric pH, antacids can influence the dissolution and absorption of many other drugs, including cimetidine and ranitidine. These interactions can be minimized by allowing 1 hour between taking antacids and these other drugs. Elevation of urinary pH can accelerate excretion of acidic drugs and delay excretion of basic drugs. Antacid Families There are four major groups of antacids: (1) aluminum compounds, (2) magnesium compounds, (3) calcium compounds, and (4) sodium compounds. In this section, we discuss the two most commonly used antacids—magnesium hydroxide and aluminum hydroxide—and two less commonly used drugs—calcium carbonate and sodium bicarbonate. Magnesium Hydroxide This antacid is rapid acting and produces long-lasting effects. The liquid formulation of magnesium hydroxide is often referred to as milk of magnesia. The most prominent adverse effect is diarrhea, which results from retention of water in the intestinal lumen. To compensate for this effect, magnesium hydroxide is usually administered in combination with aluminum hydroxide, an antacid that promotes constipation. However, if the dose of magnesium hydroxide is sufficiently high, no amount of aluminum hydroxide will prevent diarrhea. Because stimulation of the bowel can be hazardous for patients with intestinal obstruction or appendicitis, magnesium hydroxide should be avoided in those with undiagnosed abdominal pain. Because of its effect on the bowel, magnesium hydroxide is frequently employed as a laxative (see Chapter 63). In patients with renal impairment, magnesium may accumulate to high levels, causing signs of toxicity (e. Aluminum Hydroxide This drug is slow acting but produces effects of long duration. Although rarely used alone, this compound is widely used in combination with magnesium hydroxide (see Table 62. Aluminum hydroxide preparations contain significant amounts of sodium; appropriate caution should be exercised. By binding with phosphate, the drug can reduce phosphate absorption and can thereby cause hypophosphatemia. Calcium Carbonate Calcium carbonate, like magnesium hydroxide, is rapid acting and produces effects of long duration. Because of these properties, calcium carbonate was once considered the ideal antacid. However, because of concerns about acid rebound (stimulation of acid secretion), use of calcium carbonate has declined. The principal adverse effect is constipation, which can be overcome by combining calcium carbonate with a magnesium-containing antacid (e. Calcium carbonate releases carbon dioxide in the stomach and can thereby cause eructation (belching) and flatulence. Rarely, systemic absorption is sufficient to produce the milk-alkali syndrome, a condition characterized by hypercalcemia, metabolic alkalosis, soft tissue calcification, and impaired renal function. Combination Packs Three combination packs—Omeclamox-Pak, Pylera, and Prevpac—are available for treating H. Omeclamox-Pak The Omeclamox-Pak contains omeprazole delayed-release capsules (20 mg), clarithromycin tablets (500 mg), and amoxicillin (500 mg). One dose consists of 1 omeprazole capsule, 1 clarithromycin tablet, and 2 amoxicillin capsules. Pylera The Pylera pack consists of capsules that contain three drugs each: bismuth subcitrate potassium (140 mg), metronidazole (125 mg), and tetracycline (125 mg). Prevpac The Prevpac pack contains lansoprazole [Prevacid] capsules (30 mg), amoxicillin capsules (500 mg), and clarithromycin tablets (500 mg). One dose consists of 1 lansoprazole capsule, 2 amoxicillin capsules, and 1 clarithromycin tablet. These agents can soften the stool, increase stool volume, hasten fecal passage through the intestine, and facilitate evacuation from the rectum. Misuse of laxatives is largely the result of misconceptions about what constitutes normal bowel function.
Large bowel obstruction from a mechanical cause has a poorer prognosis and higher morbidity since an emergency operation is needed lopressor 100 mg amex. Additionally 100 mg lopressor with visa, the patient is already nutritionally depleted from the obstructive mass in the intestine as well as from weight loss from malignancy lopressor 25 mg fast delivery. The added stress of operation will increase his baseline energy expenditure and his nutritional requirements purchase lopressor 25 mg mastercard. The presence of rype 2 diabetes may mean that some degree of renal insuficiency is present and that there may be an increased risk for infection. An acute fare ofgout is possible from the catabolic state after surgery or as a result of the fuid shifts caused by surgery. This estimates the right atrial pressure, refecting the amount of the blood in the venous system returning to the heart. This can afect varying proportions of the lungs and is commonly seen after injury or surgery, especially if breathing is restricted by pain or fatigue. Examples include pulmonary edema, bowel wall edema, and fluid forced into the bowel lumen in cases of obstruction and retroperitoneal fluid sequestration with pancreatitis. Understanding ofthese issues is critical for the anticipation and treatment of complications, addressing the needs of the postoperative patients, and optimizing communications between the intensive care providers and the surgical specialists. It is important for the clinician to be aware of the complications that can occur and to be vigilant about looking out for those that can cause serious morbidity and even mortality. Co mplications Categorized by Systems Cardiac complications include acute coronary syndrome, myocardial infarctions, car diac arrhythmias, and congestive heart failure. Arrhythmias such as atrial fibrillation often occur due to fluid shifts throughout the body after an operation, placing more stress on the atria of the heart. Pulmonary complications can be closely linked to cardiac dysfnction in which the ability to adequately distribute intravascular fluid may be lost, causing a backup of fluid in the lungs, as in the case of pulmonary edema. Acute kidney injuries can be classified into pre-renal, renal, and post-renal categories. Pre-renal causes are due to hypoperfsion of the kidney as seen in dehydration, fluid losses from vomiting/diarrhea, or as a result of an operation, poor intake or inadequate repletion, and cardiogenic shock or significant blood loss. Insensible fluid losses are increased during an operation, especially if the abdomen is left open postoperatively. Renal causes of oliguria are from damage to the kidney itself, such as acute tubular necrosis from ischemia or medication toxicity. Post-renal causes are due to obstruc tion of urine flow, such as Foley catheter blockage, prostatic hypertrophy or com pression from tumor, hematoma, or fluid collection. Causes of post-renal (obstructive) oliguria can usually be found via physical examination or imaging. Fever can be a sign ofcomplications and can be divided into 3 categories based on timing. Immediately postoperative fever (<24 hours) may be a response to surgery or atelectasis, although in some cases a necrotizing wound infection (Clostridium or group A Streptococcus) can be the cause. After 72 hours, fever is likely due to the infectious sources mentioned above or wound infections, deep internal abscesses, anastomotic leaks, prosthetic infections, or deep vein thrombosis. Rarely, entities such as acal culous cholecystitis, most often seen in critically ill patients, can also be a cause of fever. Wound complications may occur in any patient although appropriate preoperative antibiotics, meticulous operative technique, and hemostasis are the most efective prevention. There is no additional benefit in the extension of prophylactic anti biotics beyond the immediate postoperative period. High-risk patients for wound complications are individuals with contaminated surgical fields, impaired blood flow to healing tissues from hypotension, diabetes, obesity, or smoking, and those who are immunocompromised. Wound complications include hematomas and seromas, infection in either superficial or deep spaces, and fascial dehiscence or incisional hernias. Wounds or hematomas/seromas that appear infected (tenderness, erythema, purulence) should be opened, drained, and packed loosely. Extensive wound dehis cence at the fascial level may require repair in the operating room. Close commu nication between the intensive care provider and the surgeons are critical for the management of wound-related complications. Neurologic complications after operation are often related to the treatment of postoperative pain. While hypoxemia and stroke can cause neurological changes, electrolyte abnormalities and medications are also common causes. Medications for treatment ofpain, including opiates, and sedatives in critically ill patients may cause delirium, agitation, and somnolence. Disturbances Produced by Opertive Stress on the Va rious Systems Cardiovascular: Due to increased postoperative metabolic demands, cardiac output increases, leading to higher oxygen requirements of cardiac myocytes. Pulmonary: Oxygen consumption demands are increased postoperatively due to increased metabolic demands. Ventilation and oxygenation problems in the post operative period may arise from the combination of increased 02 demand and com promised vital capacities. Surgical stresses and immobility render the patients susceptible to venous thromboembolic complications. Conditions such as trauma, sep sis, and burns further contribute to the increase in metabolic demands. Critically ill patients have accelerated breakdown of muscle protein for the reprioritization of acute-phase protein synthesis. Hyperglycemia in the postoperative patient is common and is caused by both increase in glucose production by the liver and decrease in uptake of glucose by insulin-dependent tissues. Untreated hypergly cemia contributes to glycosuria, excess fluid losses, and impairment of leukocyte function leading to infections. Glucose monitoring and treatment with insulin are essential in the postoperative patients. Insuficient adrenal functions can be exac erbated by surgical stresses and/or sepsis. This may be manifested by hypotension that is unresponsive to standard fuid administration. In some instances, adrenal dysfnction can manifest as unexplained fever, hypoglycemia, confsion, lethargy, and abdominal pain. A patient with long-term steroid medication use history is vulnerable to the development of adrenal insuficiency in the face of surgical stress, sepsis, or trauma. Gastrointestinal: Patients who are not intubated can be expected to resume oral intake shortly after an operation. In patients who are intubated and/or those who are not expected to take in adequate oral calories for prolonged periods of time, supplemen tal nutrition via enteral tube should be anticipated and implemented. It is possible for adhesions to form and bowel obstructions to occur within days after surgery, although most obstructive complications secondary to adhesions occur later. Critically ill patients are also at risk for stress ulcers, where hypoperfsion, loss of host gastric barrier functions, and gastric acidity can produce mucosal injuries. However, those who are medically compromised require more carefl pre- and perioperative evaluations to assess for fitness for surgery and ensure favor able outcomes.
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