By F. Charles. The McGregor School of Antioch University. 2019.
Hypokalemia Potassium entering the body is largely stored in the cells and then excreted in the urine cheap kamagra effervescent 100mg visa. Thus order 100mg kamagra effervescent amex, a reduction in the plasma potassium concentration can result from decreased intake discount kamagra effervescent express, increased cellular uptake, or increased losses. These losses, which are the most common contributors to hypokalemia, can occur via the urine, the gastrointestinal tract, or, less commonly, through the skin (Table 199. Because the kidney can lower potassium excretion to less than 25 mEq per day in response to potassium depletion, decreased intake alone rarely causes hypokalemia, but it can enhance the severity of other causes of potassium depletion such as diuretic therapy. The transcellular hydrogen ion shifts accompanying metabolic and respiratory alkalosis obligate increased sequestration of potassium in cells. In general, this direct effect is relatively small because the plasma potassium concentration falls to less than 0. This phenomenon provides the rationale for the administration of sodium bicarbonate to treat the hyperkalemia of metabolic acidosis. Despite the fact that the direct effect of alkalemia is relatively small, hypokalemia is common in metabolic alkalosis. The major reason for this association is that the underlying cause (diuretics, vomiting, or hyperaldosteronism) leads to losses of both hydrogen and potassium ions. This effect is most prominent after the administration of insulin to patients with diabetic ketoacidosis or severe nonketotic hyperglycemia. The plasma potassium concentration can also be reduced in nondiabetic patients by a carbohydrate load. Thus, intravenous administration of potassium chloride in a dextrose-containing solution in an effort to correct hypokalemia can transiently further reduce the plasma potassium concentration and, possibly, lead to cardiac arrhythmias. As a result, transient hypokalemia can occur with stress-induced release of epinephrine, as in acute illness, coronary ischemia, theophylline intoxication, or alcohol withdrawal. This effect must be considered when diuretic therapy is used for the treatment of hypertension in patients receiving β-agonists for asthma or chronic lung disease. The hypokalemic response to epinephrine can be blocked by a nonselective β-blocker (such as propranolol), but a β1-selective agent (such as atenolol) offers no protection, at least at lower doses (<100 mg per day). Hypokalemic periodic paralysis is a rare disorder of uncertain cause characterized by potentially fatal episodes of muscle weakness or paralysis that can affect the respiratory muscles. Acute attacks—in which the sudden movement of potassium into the cells can lower the plasma potassium concentration to as low as 1. Hypokalemic periodic paralysis may be familial with autosomal dominant inheritance, or it may be acquired in patients (often, but not exclusively, Asian men) with thyrotoxicosis. Oral administration of 60 to 120 mEq of potassium chloride usually aborts acute attacks within 15 to 20 minutes. The presence of hypokalemia must be confirmed before therapy because potassium can worsen episodes caused by the normokalemic or hyperkalemic forms of periodic paralysis. Furthermore, excess potassium administration during an acute episode may lead to posttreatment hyperkalemia as potassium moves back out of the cells. An acute increase in hematopoietic cell production is associated with potassium uptake by the new cells and possible hypokalemia. This most often occurs after the administration of vitamin B12 or folic acid to treat a megaloblastic anemia or of granulocyte-macrophage colony-stimulating factor to treat neutropenia. This phenomenon has been described in patients with acute myeloid leukemia and a high white blood cell count. In these patients, the measured plasma potassium concentration may be less than 1 mEq per L (without symptoms) if the blood is allowed to stand at room temperature for a prolonged period before separation of the plasma from the cells. Accidental or induced hypothermia (as occurs during cardiac bypass) can accelerate potassium movement into the cells and lower the plasma potassium concentration to less than 3. In contrast, hyperkalemia in an individual with severe hypothermia usually signifies irreversible tissue necrosis. Barium sulfide, used in pesticides, radiologic imaging, and depilatory agents, has been reported to cause severe transient hypokalemia when ingested . Loss of gastric or intestinal secretions from any cause (vomiting, diarrhea, laxatives, or tube drainage) is associated with potassium wasting and, possibly, hypokalemia. However, it should be emphasized that the concentration of potassium in gastric secretions is relatively low (5 to 10 mEq per L) and that the potassium depletion is primarily because of increased urinary losses. The metabolic alkalosis that results from loss of gastric secretions raises the plasma bicarbonate concentration and, therefore, the filtered bicarbonate load above its proximal tubular reabsorptive threshold. More sodium bicarbonate and water are thus delivered to the distal potassium secretory site in the presence of hypovolemia-induced aldosterone release. Secreted potassium combines with the negatively charged bicarbonate and is excreted in the final urine, leading to hypokalemia. The urinary potassium wasting seen with loss of gastric secretions is typically most prominent in the first few days; thereafter, proximal bicarbonate reabsorptive capacity increases, leading to a marked reduction in urinary sodium, bicarbonate, and potassium excretion. Urinary potassium excretion is mostly derived from potassium secretion in the distal nephron, particularly by the principal cells in the cortical collecting tubule. This process is primarily influenced by two factors: aldosterone and the distal delivery of sodium and water. The removal of cationic sodium makes the lumen relatively electronegative, thereby promoting passive potassium secretion from the tubular cell into the lumen through specific potassium channels in the luminal membrane. Any diuretic that acts proximal to the potassium secretory site, including carbonic anhydrase inhibitors and loop and thiazide diuretics, increases distal delivery and, via the induction of volume depletion, activates the renin–angiotensin–aldosterone system. Urinary potassium wasting is characteristic of any condition associated with primary hypersecretion of a mineralocorticoid, as occurs with an aldosterone-producing adrenal adenoma. Affected patients are usually hypertensive, and the differential diagnosis includes diuretic therapy (which may be surreptitious) in a patient with underlying hypertension and renovascular disease, in which increased secretion of renin leads to enhanced aldosterone release. The presence of nonreabsorbable anions in the filtrate draws increased amounts of sodium to the distal nephron where it is reabsorbed at the expense of potassium. Examples of nonreabsorbable anions include bicarbonate in vomiting-induced metabolic alkalosis, β-hydroxybutyrate in diabetic ketoacidosis, hippurate in toluene exposure (glue sniffing), and penicillin in patients receiving high-dose penicillin therapy. Both the resulting decrease in distal chloride delivery (limiting the ability of chloride reabsorption to dissipate the lumen-negative gradient) and the enhanced secretion of aldosterone promote potassium secretion. Increased urinary potassium losses can occur in several forms of metabolic acidosis by mechanisms similar to those already described. In diabetic ketoacidosis, for example, increased distal sodium and water delivery (because of the glucose-induced osmotic diuresis), hypovolemia-induced hyperaldosteronism, and β- hydroxybutyrate acting as a nonreabsorbable anion all can contribute to potassium wasting. In many cases, such as with diuretic therapy, vomiting, or diarrhea, there are concurrent potassium and magnesium losses. A direct effect of magnesium on tubular potassium transport is likely the mechanism by which hypomagnesemia promotes kaliuresis . Diagnosis of concomitant hypomagnesemia is particularly important because the hypokalemia often cannot be corrected until the magnesium deficit is repaired. Occasionally, renal diseases associated with decreased proximal, loop, or distal sodium reabsorption can lead to hypokalemia via a mechanism similar to that induced by diuretics. This problem may arise in patients with Bartter’s syndrome or Gitelman’s syndrome, tubulointerstitial diseases, such as interstitial nephritis as a result of Sjögren’s syndrome or lupus, hypercalcemia, and tubular injury induced by lysozyme in patients with acute monocytic or myelomonocytic leukemia. Increased potassium uptake by the leukemic cells may also contribute to the fall in the plasma potassium concentration. In the presence of potassium depletion, healthy subjects can lower their urinary potassium concentration to 5 to 10 mEq per L.
Introducer Technique the introducer technique uses a peel-away introducer technique originally developed for the placement of cardiac pacemakers and central venous catheters buy kamagra effervescent in united states online. The gastroscope is inserted into the stomach buy discount kamagra effervescent online, and an appropriate position for placement of the tube is identified order kamagra effervescent with a visa. After infiltration of the skin with local anesthetic, a 16- or 18-gauge needle is introduced into the stomach. Using a twisting motion, a 16-Fr introducer with a peel-away sheath is passed over the guidewire into the gastric lumen [19,20]. The guidewire and introducer are removed, leaving in place the sheath that allows placement of a 14-Fr Foley catheter. A second, smaller feeding tube can be attached and passed through the gastrostomy tube and advanced endoscopically into the duodenum or jejunum. An alternative method is to grasp a suture at the tip of the feeding tube or the distal tip of the tube itself and pass the tube into the duodenum, using forceps advanced through the biopsy channel of the endoscope. This obviates the need to pass the gastroscope into the duodenum, which may result in dislodgment of the tube when the endoscope is withdrawn. New methods using balloon-assisted enteroscopy with fluoroscopy have improved technical success rates to 96% . Fluoroscopic Technique Percutaneous gastrostomy and gastrojejunostomy can also be performed using fluoroscopy [26,27]. The stomach is insufflated with air using a nasogastric tube or a skinny needle if the patient is obstructed proximally. Once the stomach is distended and position is checked again with fluoroscopy, the stomach is punctured with an 18-gauge needle. A heavy-duty wire is passed, and the tract is dilated to accommodate a gastrostomy or gastrojejunostomy tube. Complications the most common complication after percutaneous placement of enteral feeding tubes is infection, usually involving the cutaneous exit site and surrounding tissue . Gastrointestinal hemorrhage has been reported, but it is usually caused by excessive tension on the tube, leading to necrosis of the stomach wall. Gastrocolic fistulas, which develop if the colon is interposed between the anterior abdominal wall and the stomach when the needle is introduced, have been reported. Separation of the stomach from the anterior abdominal wall can occur, resulting in peritonitis when enteral feeding is initiated. Another potential complication is pneumoperitoneum, secondary to air escaping after puncture of the stomach during the procedure, and is usually clinically insignificant. If the patient develops fever and abdominal tenderness, a Gastrografin study should be obtained to exclude the presence of a leak. All percutaneous gastrostomy and jejunostomy procedures described here have been established as safe and effective. The method is selected on the basis of the endoscopist’s experience and training and the patient’s nutritional needs. Occasionally, an operation solely for tube placement is performed in patients requiring permanent tube feedings when a percutaneous approach is contraindicated or unsuccessful. Gastrostomy Gastrostomy is a simple procedure when performed as part of another intra-abdominal operation. This may reflect the poor nutritional status and associated medical problems in many patients who undergo this procedure. Potential complications include wound infection, dehiscence, gastrostomy disruption, internal or external leakage, gastric hemorrhage, and tube migration. Needle–Catheter Jejunostomy the needle–catheter jejunostomy procedure consists of the insertion of a small (5-Fr) polyethylene catheter into the small intestine at the time of laparotomy for another indication. A needle is used to create a submucosal tunnel from the serosa to the mucosa on the antimesenteric border of the jejunum. The catheter is brought out through the anterior abdominal wall, and the limb of the jejunum is secured to the anterior abdominal wall with sutures. The potential complications are similar to those associated with gastrostomy, but patients may have a higher incidence of diarrhea. Occlusion of the needle–catheter jejunostomy is common because of its small luminal diameter, and elemental nutritional formulas are preferentially used. Transgastric Jejunostomy Critically ill patients who undergo laparotomy commonly require gastric decompression and a surgically placed tube for enteral nutritional support. Routine placement of separate gastrostomy and jejunostomy tubes is common in this patient population and achieves the objective of chronic gastric decompression and early initiation of enteral nutritional support through the jejunostomy. Technical advances in surgically placed enteral feeding tubes led to the development of transgastric jejunostomy  and duodenostomy tubes, which allow simultaneous decompression of the stomach and distal feeding into the duodenum or the jejunum. The advantage of these tubes is that only one enterotomy into the stomach is needed, eliminating the possible complications associated with open jejunostomy tube placement. In addition, only one tube is necessary for gastric decompression and jejunal feeding, eliminating the potential complications of two separate tubes for this purpose. The transgastric jejunostomy tube is preferred to transgastric duodenostomy tube because it is associated with less reflux of feedings into the stomach and a decreased risk of aspiration pneumonia. Surgical placement of transgastric jejunostomy tubes at the time of laparotomy is recommended for patients who likely require prolonged gastric decompression and enteral feeding. This approach is often used for patients requiring prolonged supplemental enteral nutritional support after discharge from the hospital. Bolus feeding can be associated with serious side effects, including gastric distention, nausea, cramping, and aspiration. The intermittent bolus method should not be used when feeding into the duodenum or the jejunum because boluses of formula can cause distention, cramping, and diarrhea. Gravity-infusion systems allow the formula to drip continuously during 16 to 24 hours or intermittently during 20 to 30 minutes, four to six times per day. The main advantages of this approach are simplicity, low cost, and close simulation of a normal feeding pattern. Continuous pump infusion is the preferred method for the delivery of enteral nutrition in the critically ill patient. A peristaltic pump can be used to provide a continuous infusion of formula at a precisely controlled flow rate, which decreases problems with distention and diarrhea. Gastric residuals tend to be smaller with continuous pump-fed infusions, and the risk of aspiration may be decreased. For medications that are better absorbed in an empty stomach, tube feedings should be suspended for 30 to 60 minutes before administration. Medications should be administered in an elixir formulation via enteral feeding tubes, whenever possible, to prevent occlusion of the tube. To use an enteral feeding tube to administer medications dispensed in tablet form, often the pills must be crushed and delivered as slurry mixed with water. This is inappropriate for some medications, however, such as those absorbed sublingually or formulated as a sustained-released tablet or capsule. Nasopulmonary Intubation Passage of an enteral feeding tube into the tracheobronchial tree most commonly occurs in patients with diminished cough or gag reflexes as a result of obtundation, altered mental status, or other causes such as the presence of endotracheal intubation.
In the last decade buy 100 mg kamagra effervescent mastercard, A 13-valent conjugate vaccine is now available which covers several new vaccines have been developed and are available about 70% of strains worldwide and India buy kamagra effervescent cheap online. It has 1 cheap kamagra effervescent 100 mg amex, 5, 7F, 3, in India apart from the basic vaccines included in the National 6A and 19A in addition to the 7-valent vaccine. Indian Academy of Pediatrics Committee on 7-valent vaccine as it has better serotype coverage. Physician should be able of the schedule to be followed in various ages and situations to counsel the parents regarding the efficacy and importance should be as per recommendation of Indian Academy of of these vaccines in the present health situation. In India too, almost all these vaccines find a place in in addition to the 7-valent strains. The vaccine is expected Currently two types of pneumococcal vaccines are marketed to be licensed in India in the near future. This vaccine doses of diphtheria and acellular pertussis components; covers most of the prevalent strains of pneumococcus hence can be used in children above 7 years. A dose of this vaccine can be given subcutaneously or intramuscularly in children, more than 2 at 10–11 years of age. The vaccine being a capsular polysaccharide 7 years if the child has not received vaccine before. This is not immunogenic in children of less than 2 years of vaccine is now routinely recommended as a single booster age. Polysaccharide vaccine fails to elicit a protective immune Typhoid Vaccine response in children less than 2 years, even though 80% of the Typhoid vaccine was included in the National Immunization pneumococcal disease occurs in children less than 2 years of Schedule till 1987; but discontinued because the vaccine age. Two This vaccine contains seven purified capsular polysac- types of typhoid vaccines are now available. It has serotypes 4, 6B, 9V, 14, 18C, 19F, 23F, responsible for 85% of invasive disease and 65% the Vi antigen of Salmonella typhi is a capsular antigen with 194 of otitis media in western countries. It covers only 50% of known virulence property of the organism and is available the prevalent strains in India. Schedule is as injectable vaccine containing 25 mg purified Vi capsular polysaccharide per dose. A combined HepA-HepB vaccine formulation is include pain, erythema and induration at the local site and also available for use in older children, adolescents and adults. All the reactions are of mild nature and self- Dose and schedule: Hepatitis A vaccine is given in a limiting. Conjugated Typhoid Vaccine Adverse effects: Adverse reactions are minimal and Vi antigen is conjugated with nontoxic recombinant include self-limiting local reactions at injection site. The Live Attenuated Hepatitis A Vaccine available conjugate typhoid vaccine in India lacks large This has been manufactured from the H2 strain in China. The scale epidemiological studies on efficacy and hence is not vaccine has been widely used in China. It can be administered to children given subcutaneously in a prime-boost two doses schedule below 1 year and will be helpful in endemic regions. This vaccine is prepared from the virus of the original Salk strain grown in monkey’s kidney, human diploid or Vero cell Varicella Vaccine line and is inactivated by formalin. As a catch-up vaccine in children less than 5 years vaccines one week after vaccination. Both the vaccine formulations are now recommended Vaccines recommended under in women up to 45 years of age. The dose is same irrespective of Currently two live attenuated oral vaccines are available. Intradermal schedules have been attenuated human rotavirus vaccine derived from recommended at government centres. It is available as a lyophilized vaccine to be reconstituted Pre-exposure Prophylaxis with a diluent. First dose can be given at 6 weeks (not This is indicated in persons at high-risk of exposure, e. It is available as a liquid formulation and should Inactivated Influenza Vaccine not be frozen or injected. This is available as a whole cell or split virus vaccine or Both vaccines have an efficacy of 85–98% against severe subunit surface antigen formulations. Whole cell vaccines are rotavirus gastroenteritis and 42–60% against hospitalization currently not in use due to side effects. Monovalent schedule in countries where more than 10% of under-five vaccine has a novel H1N1 2009 strain. After 9 years, This is a live attenuated vaccine produced from either only a single dose of 0. The vaccine is not recommended compromised and pregnant; and should be avoided in for routine use and is to be given in epidemic situations children less than 5 years of age with reactive airway disease. It is also recommended for travelers to endemic Japanese b encephalitis (Je) Vaccine countries and mandatory for Haj pilgrimage. Updated given in a dose of 1 ml subcutaneously on days 0, 7 and 30 for recommendations for use of tetanus toxoid, reduced travellers planning to spend more than 30 days in endemic diphtheria toxoid and acellular pertussis (Tdap) vaccine from area at least 10 days before travel. Pneumococcal in a campaign mode to children aged 1–15 years in certain conjugate vaccines for preventing vaccine-type invasive hyperendemic districts of India. Recommendations C, bivalent A and C and a tetravalent vaccine containing for rotavirus vaccination: A worldwide perspective. An effective logistics system and a well-maintained cold chain are essential for safe and effective immunization service different Vaccine storage equipment for delivery. An improperly functioning cold chain can lead to wasted vaccines, missed opportunities to immunize due to immunization Program lack of vaccines, and children receiving vaccines that do not There are several cold chain maintenance equipment of protect them as intended or that actually make them sick. The cold-chain is the system of storing and transporting Storage equipment could be electrical as well as non- vaccines at recommended temperature from the point of electrical (Table 5. Equipment to store and transport vaccines and to Deep freezers have top opening lid. The cabinet temperature monitor the temperature is maintained between –15°C and –25°C. Procedures to ensure that vaccines are stored and used to prepare icepacks and should not be used to store transported at appropriate temperature. The vaccines which are not stored in vaccine safe with, as little as, 8 hours continuous electricity the recommended temperature range get degraded. Hence they are suitable for use in addition to higher temperature, freezing of vaccines also the area with poor power supply. They are not designed for the special temperature needs of vaccines and the safety of vaccines is at risk. For vaccine storage, the domestic refrigerator has following drawbacks: • Temperature varies significantly every time the door is opened. In emergency, they can also be refrigerators used to store vaccines and frozen ice packs. Before placing • Placement of refrigerator: Refrigerator should be vaccines in the cold boxes, first place conditioned ice placed away from exposure to direct sunlight and packs at the bottom and sides of the cold box and load the vaccines in cartons or polythene bags.
Pathogens are typical nosocomial organisms: Gram-positive cocci 100mg kamagra effervescent free shipping, particularly staphylococci buy kamagra effervescent 100mg on-line, are the most frequent etiologies buy kamagra effervescent 100 mg mastercard, followed by Gram-negative bacilli including Pseudomonas aeruginosa and Candida sp. In the years since 2000, antimicrobial resistance has increased among the usual causative organisms, particularly staphylococci and enterococci, increasing the challenge of treating these infections. Certain organisms also produce a slime around indwelling devices that provides a further barrier to antimicrobial penetration and alters killing conditions. In vitro and animal model systems can suggest potential approaches to therapy, but clinical outcomes are the final arbiter of whether a particular drug or combination of drugs has worked for the patient with endocarditis. In the clearest case, “Bacteriologic cure rates ≥ 98% may be anticipated in patients who complete 4 weeks of therapy with parenteral penicillin or ceftriaxone for endocarditis caused by highly penicillin-susceptible viridans group streptococci or S. Extensive reviews of published data and the clinical wisdom of experts in the field provide the basis for the therapeutic recommendations of various guidelines (, United States; , Europe; , United Kingdom [see individual references for Web site addresses]). For prosthetic valve infections, 6-week therapy with the β-lactam is recommended, and gentamicin is optional . Vancomycin is recommended for patients with endocarditis due to streptococci only if they are unable to tolerate penicillin or ceftriaxone. Desensitization to a β-lactam antibiotic, rather than use of vancomycin, should be strongly considered for patients with anaphylactic β-lactam allergies. If vancomycin must be used because the patient is intolerant to β-lactams, gentamicin is not recommended . The European guidelines recommend use of ceftriaxone rather than penicillin or ampicillin in this circumstance (unless the susceptibility of the organism requires addition of vancomycin) . Even in the absence of meningitis, high-dose penicillin or ceftriaxone should be used, and the addition of vancomycin and rifampin may be considered if the S. Controlled trials have shown that the addition of gentamicin does not improve outcome in native valve S. The European guidelines  recommend waiting 3 to 5 days before starting rifampin; this provides time to be sure the organism is susceptible, and may decrease the likelihood of selecting for rifampin resistance while the organism is still replicating rapidly. The difficulty with treating these strains may not be entirely due to their resistance to vancomycin: higher in-hospital mortality was also found among patients with endocarditis due to methicillin-susceptible S. The addition of synergistic gentamicin is not thought to be more useful in this situation than for oxacillin-susceptible disease, and coadministration with vancomycin may increase toxicity. Addition of rifampin to vancomycin therapy is not recommended due to a lack of benefit on either survival or duration of bacteremia . Enterococci For many years, enterococcal endocarditis has been the one instance where the combination of penicillin, ampicillin, or vancomycin with an aminoglycoside (streptomycin or gentamicin) was required for clinical efficacy . An observational study comparing outcomes for patients who received ampicillin plus ceftriaxone or ampicillin plus gentamicin, as chosen by their treating physicians, found equivalent efficacy and much less toxicity for the double β-lactam combination [177,178]. This regimen is now recommended at the same level as the traditional combination of ampicillin plus an aminoglycoside in both U. If the enterococcus is ampicillin-resistant due to β-lactamase production, one of the drugs that combine ampicillin or amoxicillin with a β-lactamase inhibitor (e. Although the aminoglycoside has conventionally been recommended for the full duration of therapy, a retrospective study in Sweden found good results for patients who received only 15 days of aminoglycoside . A subsequent study in Denmark, looking at outcomes before and after limiting the duration of aminoglycoside therapy to 2 weeks while continuing the β-lactam for a total of 4 to 6 weeks, found that patients receiving 2 and 6 weeks of aminoglycoside therapy had equivalent outcomes . For disease of longer duration, prosthetic valve involvement, or vancomycin-based therapy, treatment is prolonged to 6 weeks with both drugs [44,103]. A 6-week course is also recommended for double β-lactam therapy for both native and prosthetic valve disease, as well as intracardiac device infection. The quinupristin– dalfopristin compassionate-plea program reported clinical and bacteriologic response in only 2 out of 10 (0 of 1 evaluable) patients . Ampicillin–sulbactam may be used, but the combination of ampicillin and gentamicin is no longer recommended. Candida Candida endocarditis has generally been regarded as an indication for valve replacement surgery, but often the patients who get this infection have been too ill for surgery. Factors associated with survival of some of these high-risk patients in the absence of cardiac surgery include receiving initial combination antifungal therapy (most often amphotericin B plus 5-flucytosine) followed by long-term suppressive therapy with fluconazole [188,189]. Case reports of good outcomes for patients treated with caspofungin, including four who did not have valve replacement [190–192], are now supported by a larger experience indicating that echinocandins are equally effective . Unfortunately, the mortality rate remains high (36% in hospital and 59% at 1 year), with no impact by choice of drug or performance of surgery in this series of 70 cases from 2000 to 2010 . Empiric Therapy Patients with endocarditis who require intensive care at admission will most likely have the acute form of the disease due to virulent pathogens such as S. The British guideline is the only one that specifically addresses empiric therapy for the critically ill patient; it recommends vancomycin plus meropenem . Enterococcus is the third most common etiology among injection drug users  and the cause of more than 10% (13% in North America ) of all cases of endocarditis in recent series [9,96]. The same patients are among those with risk factors for extended- spectrum β-lactamase-producing Enterobacteriaceae or P. Supportive Care and Monitoring Careful clinical monitoring of the patient on therapy for endocarditis includes surveillance for fever, evidence of congestive heart failure or other cardiac complication, metastatic infection, adverse effects of antimicrobial drugs (and levels, when appropriate), changes in renal function, and superinfection. Echocardiographic imaging should be repeated as described above to better define disease in patients whose initial echocardiography was unrevealing. It should also be repeated at any time when clinical changes, such as new murmur, embolism, persisting fever, heart failure, or atrioventricular block suggest poor control of disease or complications [44,103]; it may also be wise to repeat this study to detect new silent complications and follow vegetation size, especially for endocarditis caused by virulent organisms . Echocardiography should also be repeated at the end of therapy as to define the patient’s new baseline [44,103]. Recrudescence of fever after initial resolution most often indicates a new problem outside the heart, such as catheter-associated sepsis, drug fever, or antibiotic-associated Clostridium difficile colitis, but superinfection of the endocarditic valve may occur. Unless there is another immediately obvious cause, persistent or recurrent fever should prompt repeat echocardiography. The possible need for cardiac surgery mandates discontinuation of warfarin and substitution of heparin when the diagnosis of endocarditis is made for patients on anticoagulant therapy for prosthetic valves or other indications . Anticoagulation in endocarditis carries the risk of converting bland emboli (infarcts) to hemorrhagic ones, and thus should be carefully monitored and continued with caution. Role of Cardiac Surgery At times, failure of antibiotics to sterilize the blood necessitates surgical debridement and removal of the infected focus—the valve. Even if bacteriologic cure is achieved, some patients have sufficient valvular damage that they will die of hemodynamic compromise unless a valve is replaced. The surprisingly favorable outcomes of a number of patients operated on in these desperate circumstances have led to consideration of cardiac surgery much earlier in the course of endocarditis [194–197]. The two indications for surgery already mentioned—microbiologic failure and congestive heart failure—are now well accepted. The challenge is to identify patients who would eventually meet these criteria before their clinical condition deteriorates. Conventional blood cultures should become sterile within 7 days after the institution of appropriate antibiotic therapy [44,93,192,197].
Technique the use of a double lumen endotracheal tube allows the left lung to be deflated buy kamagra effervescent from india, and facilitates exposure generic 100 mg kamagra effervescent free shipping. A left thoracotomy through the fifth or sixth intercostal space provides good access to both the descending aorta and the left ventricle buy kamagra effervescent with amex. The inferior pulmonary ligament is ligated and divided to free up the left lung and improve access to the descending aorta. A disease-free segment of the aorta is identified and excluded with a large Satinsky partial occluding clamp. Calcification of Descending Aorta If this procedure is contemplated, the presence of severe atherosclerotic disease and/or calcification of the descending aorta should be ruled out. The pericardium is opened anterior and parallel to the left phrenic nerve and suspended with traction sutures. A segment of the anterior wall of the left ventricle near the apex is selected for placement of the valve conduit. Multiple U-shaped 2-0 Ticron sutures, buttressed with soft Teflon felt, are passed deeply through the thickened muscle and then through the sewing collar of the connector. Through a stab wound, a muscle coring device is introduced to create the outflow tract through which the rigid angled apical connector is quickly placed into the left ventricle. All sutures are securely tied, and the suture line may be reinforced with an additional continuous suture of 3-0 Prolene. Injury to Left Anterior Descending Artery the conduit outflow tract should be well away from the coronary artery and the thinned portion of the left ventricular apex. Clot in Left Ventricle Detailed echocardiography should be done to detect the presence of blood clot in the left ventricular apex and along the septum. Location of Papillary Muscle Intraoperative transesophageal echocardiography can locate the papillary muscles and ensure that the conduit is placed away from their insertion sites. The grafts of the valve conduit and connector are appropriately trimmed and anastomosed with a continuous suture of 3-0 Prolene. The heart can be lifted and fibrillation induced to facilitate the introduction of the muscle coring device and rigid connector into the left ventricle. Fibrosis, calcification, or simply a very small aortic root can limit the maximal orifice of the aortic annulus. This mismatch results in a higher transvalvular gradient and less regression of left ventricular hypertrophy, which may lead to increased cardiac morbidity and mortality. Tilted Prosthesis Technique Depending on the type of prosthesis, by tilting the plane of implantation by 5 to 10 degrees, it is often possible to implant a larger valve into the aortic root. Starting from either end of the noncoronary annulus and arching upward to a central point 5 to 8 mm above its nadir, sutures, double-armed with needles (2-0 Ticron), are passed first through the sewing ring in a horizontal manner downward from above and then through the aortic wall. The needles are finally passed through small pledgets or strips of Teflon felt outside the aorta. Location of the Aortotomy the right margin of the aortotomy should be at a higher level than usual, 1. Buttressing of the Sutures All sutures anchoring the prosthesis onto the aortic wall above the annulus must be buttressed with Teflon pledgets or a strip of Teflon felt or pericardium. The concept of the tilting technique allows the implantation of a larger prosthesis in the supraannular position along the noncoronary annulus. Use of Bileaflet Prostheses Bileaflet prostheses have excellent hemodynamics and are preferred by many surgeons for use in patients with small aortic roots. Inappropriate Size of the Prosthesis It is pointless to attempt to insert a prosthesis whose internal orifice is larger than the orifice of the left ventricular outflow tract or aortic annulus. If the left ventricular outflow tract is too narrow, the tilting technique of valve replacement obviously will not be very rewarding. B: Maximal possible flow when left ventricular outflow tract is same size as the internal orifice of the prosthesis. C: No increase of flow with a left ventricular outflow tract that is smaller than the internal orifice of the prosthesis. A limited myectomy or shaving off excess septal muscle bulging into the left ventricular outflow tract may allow for a wider lumen and ensure the normal function of the valvular prosthesis. Patch Enlargement Technique It is always preferable to use the largest possible prosthesis whenever valve replacement is contemplated. A prosthesis larger than the aortic annulus, however, does not abolish the obstructive gradient across the left ventricle and the aorta. Therefore, if the aortic annulus is a dominant obstructive factor, it must be enlarged to accept a larger prosthesis. The oblique aortotomy is extended downward through the commissure between the noncoronary and the left coronary aortic annuli onto the subaortic fibrous curtain up to, but not including, the mitral annulus. A patch of glutaraldehyde-treated autologous pericardium or bovine pericardium is cut in the appropriate shape and size and sewn into place with a continuous 3-0 Prolene suture. When further enlargement is warranted, the incision is extended across the subaortic curtain, through P. This necessarily entails incision of the left atrial wall to a similar extent from the mitral annulus. A patch of glutaraldehyde- treated autologous pericardium or bovine pericardium of appropriate size and shape is then sewn into place with 3-0 continuous Prolene suture, incorporating the left atrial wall and the anterior mitral leaflet. Rarely, this approach may distort the mitral valve, particularly in patients with a small left atrium. These techniques of aortic root enlargement have the added advantage that the left ventricular outflow tract, as well as the aortic annulus, can be enlarged considerably. Tilting the Prosthesis the prosthesis should be sewn in with a slight tilt, as described earlier, so that the anchoring sutures that cross the patch can be tied on the outside wall of the patch 4 or 5 mm above the annulus. If the autologous pericardium appears to be thin and insecure, it can be reinforced by a patch of Gore-Tex. Hemolysis If a Gore-Tex patch or Dacron graft is used, it may be lined with autologous pericardium to prevent possible hemolysis in the postoperative period. Narrow Left Ventricular Outflow Tract the previously discussed techniques enlarge the aortic annulus quite effectively. Placement of a larger prosthesis or enlargement of the aortic annulus will not relieve the basic hemodynamic problem. Use of Aortic Homograft or Stentless Valves the excellent hemodynamics of aortic homografts and stentless bioprotheses in smaller valve sizes may provide satisfactory results without the need for a root enlargement procedure. The obstruction associated with a small aortic root can be satisfactorily relieved in most patients using one of these techniques. Endocarditis Infective endocarditis is a debilitating disease and is associated with a very high mortality. The native aortic valve leaflets become infected, and the infection may extend into the annulus and the surrounding tissues, resulting in paravalvular and root abscesses.