Post-Tonsillectomy Bleeding

Incidence and Initial Management:

-The incidence of post-tonsillectomy bleeding ranges from 2% to 4%. It is more common in teenagers and young adults than in small children. The vast majority of postoperative bleeding occurs between days 5 and 10 when the eschar separates from the tonsil beds. In rare cases, bleeding may occur in the immediate postoperative period.

-Initial management is tailored to the degree of bleeding. The clot in the tonsillar bed should be suctioned, as spontaneous hemostasis is rare with the clot in place.

-Minimal bleeding may resolve with an ice water gargle or hydrogen peroxide gargle, and older children may tolerate the application of a cautery stick with silver nitrate while awake.

-Administration of antifibrinolytics as tranexamic acid.

-Significant bleeding in a young child, however, typically involves a return to the operating room for a thorough examination of the pharynx and electrocautery hemostasis.

Preoperative Assessment and Optimization:

1-Airway Assessment:

-Although it may be difficult to assess the airway in-depth in an agitated child, observation of the external anatomy and information about airway management from the prior anesthetic should provide sufficient information.

-Even though airway management was uncomplicated previously, it may be more difficult at this time because of postoperative edema and blood-obscuring visualization of the larynx.

2-Intravascular Volume Status:

-It is possible to underestimate the degree of blood loss, since much of it may have been swallowed. Heart rate, blood pressure, and, if possible, orthostatic testing will provide information regarding volume status and guide volume resuscitation.

-Assessing for the presence of tears, moist mucus membranes, skin turgor, and urine output will be helpful as well.

-Adequate IV access, with a large-bore intravenous catheter, should be obtained, if not already present.

-Intraosseous access should be entertained in the hypovolemic, hypotensive patient if IV access cannot be obtained in a timely fashion.

-Volume resuscitation should be initiated with non-glucose-containing isotonic fluids. If the patient is hypotensive, 20 mL/kg boluses of isotonic fluid should be administered until the blood pressure normalizes.

-Transfuse red blood cells if hemodynamically unstable and hematocrit is low.

-Once the bleeding has been controlled and the patient is normovolemic, maintenance fluids should be continued.

3-Laboratory Tests:

-Hematocrit, platelet count, electrolytes, and coagulation studies.

-A specimen should also be sent for serotyping and cross match, as transfusion is a very real possibility.

-Surgery should not be delayed waiting for test results, since bleeding will continue without surgical intervention

Intraoperative Management:

-Management of the airway is of major concern, particularly the ability to visualize the larynx in the presence of ongoing bleeding.

-In preparation for induction, the following should be prepared: multiple laryngoscope blades, a styletted cuffed ETT, and large bore suction.

-The otolaryngologist should be present and tracheostomy equipment immediately available should a surgical airway become necessary.

-The patient is considered to have a full stomach, even if they have not recently eaten, because of swallowed blood.

-A rapid sequence induction is usually performed. However, in the situation where there is significant concern about the airway, a smooth mask inhalation induction with cricoid pressure can be performed with the patient in the right lateral decubitus position with the head down (tonsillectomy position) with suction immediately available. The tonsillectomy position minimizes aspiration risk by promoting the pooling of blood in the oropharynx.

-The choice of IV induction agent will depend on the volume status. Ketamine or etomidate may be used if there is ongoing concern about volume status and hemodynamic stability. Alternatively, propofol may be used but in a decreased dose.

-Muscle relaxation can be achieved with either succinylcholine or rocuronium. However, the duration of action of rocuronium at the dose recommended for rapid sequence induction (1.2 mg/kg) will likely exceed the length of the procedure.

-Volume status should be continually assessed in the face of ongoing bleeding and managed appropriately with isotonic fluids.

-The hematocrit, degree of hemodynamic stability, and status of hemostasis will dictate the need for a blood transfusion.

-Replacement of coagulation factors is rarely necessary. However, if a previously undiagnosed coagulopathy is discovered, the appropriate therapy should be initiated and a hematology consult obtained.

Postoperative Management:

-Patients should be placed in the lateral decubitus position with the head down with supplemental oxygen for transport to the PACU.

-Analgesic and antiemetic medications should be ordered.

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 Multiple Sclerosis

-Multiple sclerosis (MS) is the most common demyelinating neurological disease.

-The myelin surrounding an axon may develop normally and be lost later, but leaving the axon preserved. Alternatively, there may be some defect in the original formation of myelin as a result of an error in metabolism.

-Multiple sclerosis is thought to be autoimmune in nature. Susceptibility to MS may be genetically determined. Viral and immune factors are possibly involved.

-It is characterized by a combination of inflammation, demyelination, and axonal damage in the CNS. Disruption of the blood-brain barrier is an early event. Plaques of demyelination are scattered throughout the nervous system, usually in the optic nerve, brainstem, and spinal cord. The peripheral nerves are not involved.

Preoperative Findings:

1. The commonest presenting symptoms, in order of frequency, are limb weakness, visual disturbances, paresthesia, and incoordination. Legs are more commonly involved before the arms, with signs of spasticity and hyperreflexia. Urinary symptoms may occur.

2. Progression, with remissions and relapses, is very variable. Infection, trauma, and stress may be associated with relapses. A small increase in body temperature can cause a definite deterioration in neural function. The third trimester of pregnancy is associated with a 70% decrease in relapse rate, but this is followed by an increase of about 70% in the first 3 months postpartum. This may impair the ability of a mother to care for her baby.

3. Pain may be a prominent feature, occurring in 45% of patients.

4. Mild dementia and dysarthria may appear as the disease progresses.

5. In advanced disease, and sometimes earlier during acute relapses, respiratory complications may occur secondary to a variety of causes; they were, in decreasing order of importance, respiratory muscle weakness, bulbar weakness, and central control of breathing.

6. MRI now plays an important part in the diagnosis, and abnormalities in the white matter can be seen in 99% of cases. Gadolinium enhancement seems to reflect areas of inflammation where the blood-brain barrier has broken down.

7. Patients are treated with; baclofen, gabapentin, or beta interferon.

Anesthetic Problems:

1. Both experimentally and clinically, an increase in body temperature has been shown to cause a deterioration in nerve conduction and neurological signs.

2. Spinal anesthesia is associated with an increased incidence of neurological complications.

3. Epidural anesthesia in pregnant women with MS showed that there was no difference between those who had been given an epidural and those who had not. Temporary neurological deficits have, however, been reported. It was postulated that neurotoxicity might have resulted from the diffusion of the local anesthetic into the dural space. However, it has been suggested that concentrations of bupivacaine not greater than 0.25% should be used since postpartum relapse has been reported with those above this.

4. Local anesthesia did not significantly increase the relapse rate. However, early disruption of the blood-brain barrier in MS means that local anesthetics can cross more readily, and toxicity is more likely to occur.

5. Neuromuscular blockers. Resistance to atracurium, in association with an abnormally high concentration of skeletal muscle acetylcholine receptors, has been reported in a patient with MS and spastic paraparesis.

6. There is an increased incidence of epilepsy in MS patients.

Anesthetic Management:

1. Elective surgery should not be undertaken in the presence of fever.

2. Spinal anesthesia should probably be avoided. If a regional block is required, epidural anesthesia is preferable.

3. The maximum dose of local anesthetic should be reduced below that normally recommended. Techniques that require large doses should be avoided.

4. It was suggested that IV gamma globulin immediately after delivery protects patients from relapse in the first 6 months postpartum.

5. Patients may require treatment for pain and spasticity.

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Complications of Total Parenteral Nutrition (TPN)

I. Catheter-Related Complications:

-The hyperosmolarity of the dextrose and amino acid solutions requires infusion through large veins or central venous lines.

1-Misdirected Catheter: e.g., with subclavian vein cannulations – (mostly on the right) 10% resulted in misplacement of the catheter in the internal jugular vein.

2-Infection

3-Hematoma

4-Thrombosis

II. Carbohydrate Complications:

1-Hyperglycemia:

-Hyperglycemia is common during TPN; blood glucose levels >300 mg/dl were recorded in 20% of postoperative patients receiving TPN.

-A standard TPN regimen with 1,800 non-protein calories has ≈350 g of glucose, compared to 230 g in a standard tube feeding regimen.

-Tight glycemic control is not recommended in critically ill patients because of the risk of hypoglycemia, which has more serious consequences than hyperglycemia.

-The current recommendation for hospitalized patients is a target range of 140–180 mg% for blood glucose.

2-Insulin:

-If insulin therapy is required, regular insulin is preferred for critically ill patients, to prevent wide swings in glucose levels, by adding insulin to the TPN solutions.

-One shortcoming of IV insulin infusions is the propensity for insulin to adsorb to the plastic tubing in IV infusion sets. This affects the bioavailability of insulin but can be reduced by priming the IV infusion set with an insulin solution (e.g., 20 mL of saline containing 1 unit/mL of regular insulin). But the priming procedure must be repeated each time the IV infusion set is changed.

-SC insulin can be used for stable patients. Regimens will vary in each patient, with a combination of intermediate or long-acting insulin with rapid-acting insulin, when needed.

3-Hypophosphatemia:

-The movement of glucose into cells is associated with a similar movement of phosphate into cells, and this provides phosphate for co-factors (e.g., thiamine pyrophosphate) that participate in glucose metabolism. This intracellular shift of phosphate can result in hypophosphatemia.

4-Hypokalemia:

-Glucose movement into cells is also accompanied by an intracellular shift of potassium (which is the basis for the use of glucose and insulin to treat severe hyperkalemia). This effect is usually transient, but continued glucose loading during TPN can lead to persistent hypokalemia.

5-Hypercapnia:

-Excess carbohydrate intake promotes CO₂ retention in patients with respiratory insufficiency. This was originally attributed to the high respiratory quotient (VCO₂/VO₂) associated with carbohydrate metabolism. However, CO₂ retention is a consequence of overfeeding, and not overfeeding with carbohydrates.

III. Lipid Complications:

-Overfeeding with lipids may contribute to hepatic steatosis.

-Triggering inflammatory response: The lipid emulsions used in TPN regimens are rich in oxidizable lipids, and the oxidation of infused lipids will trigger an inflammatory response. (Oleic acid, one of the lipids in TPN, is a standard method for producing ARDS in animals), and this might explain why lipid infusions are associated with impaired oxygenation.

IV. Hepatobiliary Complications:

1-Hepatic Steatosis:

-Fat accumulation in the liver (hepatic steatosis) is common in patients receiving long-term TPN and is believed to be the result of chronic overfeeding with carbohydrates and lipids. Although this condition is associated with elevated liver enzymes, it may not be a pathological entity.

2-Cholestasis:

-The absence of lipids in the proximal small bowel prevents cholecystokinin-mediated contraction of the gallbladder. This results in bile stasis and the accumulation of sludge in the gallbladder and can lead to acalculous cholecystitis.

V. Bowel Sepsis:

-The absence of nutritional bulk in the GI tract leads to atrophic changes in the bowel mucosa and impairs bowel-associated immunity, and these changes can lead to the systemic spread of enteric pathogens.

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 Tetralogy of Fallot

-Tetralogy of Fallot (TOF) is a congenital cardiac abnormality. The primary defects are pulmonary infundibular stenosis and ventricular septal defect (VSD). The VSD is sufficiently large for the pressure in both ventricles to be equal to that of the aorta. The tetralogy is completed by two secondary features, a variable degree of overriding of the aorta, and right ventricular hypertrophy.

-Dynamic right ventricular outflow obstruction may occur (infundibular spasm), which is accentuated by sympathetic stimulation. The fraction of the right to left-shunt depends primarily upon the relative resistances between the pulmonary (or right ventricular) and systemic outflows.

-If TOF is associated with patent foramen ovale (PFO) or atrial septal defect (ASD), it is a Pentalogy of Fallot.

-The aim of the surgery is to relieve the right ventricular outflow obstruction and to close the VSD. The traditional management by a two-stage repair has been replaced by definitive correction. Recent surgical advances include conduits to connect the RV to the PA and transatrial repair of the VSD.

The problems encountered during anesthesia will depend upon whether or not corrective surgery has been undertaken, and the functional result.

Preoperative Findings:

1. Dyspnea may occur on exertion and is hypoxia-related. Cyanosis and finger clubbing are variable, depending on the degree of pulmonary stenosis and the size of the shunt. Polycythemia (erythrocytosis) is common. There is a pulmonary stenotic murmur, but no murmur from the VSD because of the size of the defect. Squatting is thought to reduce the fraction of the shunt since kinking the large arteries increases systemic vascular resistance. Squatting is commonly seen in children with uncorrected lesions.

2. ECG shows right atrial and right ventricular hypertrophy, right axis deviation, and right bundle branch block.

3. Echocardiography shows right atrial and right ventricular hypertrophy, VSD, PFO or ASD, pulmonary hypertension, and overriding of the aorta.

4. Chest X-ray shows right ventricular hypertrophy and oligemic lungs. In the 2.6–6% of individuals who also have an absent pulmonary valve, aneurysmal dilatation of the pulmonary arteries may cause bronchial compression.

5. Initial surgery may have been undertaken to anastomose a systemic to a pulmonary artery, to improve the pulmonary blood flow, and reduce cyanosis. A definitive procedure is now more commonly undertaken in infancy.

6. In patients who have undergone shunt surgery without a definitive repair, there is chronic hypoxia and polycythemia. These patients have a high mortality, and an increased risk of bacterial endocarditis, thrombotic stroke, emboli, and intracerebral abscess.

7. In adults who have undergone repair there is an increased risk of arrhythmias, conduction defects, and sudden deaths, possibly related to mechanical events, such as ventricular dilatation and stretch, in the proximity of the conduction system. However, new approaches to surgery may result in a lower incidence of such problems in the future.

Anesthetic Problems:

1. In individuals with uncorrected lesions, the right to left shunt, and hence the cyanosis, is increased by a reduction in systemic vascular resistance produced by systemic vasodilatation. This may result from factors such as hypovolemia, drug effects, or pyrexia.

2. Cyanosis is also worsened by an increase in pulmonary vascular resistance or spasm of the right ventricular infundibulum. Right ventricular outflow obstruction is due to increased contractility which is produced by increases in catecholamine output or the administration of drugs with positive inotropic effects. Anxiety, pain, hypercarbia, hypoxia, and acidosis are all precipitating factors. These cyanotic attacks or ‘tet’ spells, which can occur when awake or under anesthesia, may initiate a cycle of increasing hypoxia that can result in cerebral damage or death. Direct intraoperative observations of shunt direction and flow have been made with Doppler color flow imaging using epicardial leads. Patients with severe life-threatening hypoxemic spells, refractory to other treatments, responded to phenylephrine (5 mcg/kg plus an infusion of 0.4–2 mcg/kg/min).

3. Dehydration in the presence of polycythemia and high plasma viscosity may combine to increase the incidence of cerebral thrombosis. Polycythemia may also be associated with coagulation defects.

4. In patients with an absent pulmonary valve, positional airway compromise occurred secondary to bronchial compression of dilated pulmonary arteries.

5. A significant incidence of tracheal anomalies has been found.

6. In adults who have undergone repair, ventricular and atrial arrhythmias are common, particularly during exercise. It has been suggested that patients scheduled for elective surgery should have Holter monitors, or undergo exercise testing, in case antiarrhythmic treatment is needed first.

7. Cyanosed patients with Fallot’s rarely become pregnant. However, adults who have undergone corrective surgery are increasingly present during pregnancy with a favorable outcome.

Anesthetic Management:

1. Antibiotic prophylaxis against bacterial endocarditis.

2. A good premedication (morphine sulphate, or midazolam) to prevent excitement and anxiety.

3. In patients with cyanosis, measures are aimed at reducing the right to left shunt. Specific treatments for cyanotic attacks include:

a) Oxygen 100% to decrease PVR.

b) Pressor agents, such as phenylephrine (5-10 mcg/kg), to increase systemic vascular resistance.

c) Fluids to correct hypovolemia.

d) Propranolol (0.1 mg/kg) or Esmolol (0.5 mg/kg) to decrease outflow tract obstruction (decrease contractility and infundibular spasm).

e) Deepening of light anesthesia to reduce tachycardia associated with catecholamine output.

f) Compression of the femoral artery or the abdominal aorta against the vertebrae, sufficiently firmly to stop the femoral artery pulsations.

4. Techniques to avoid hypoxia and hypercarbia, and minimize vasodilatation and sudden increases in cardiac output. Ketamine, and Morphine sulphate (0.05-0.1 mg/kg), have been used.

5. Hydration is maintained in the perioperative period and, if there is severe polycythemia, venesection may be necessary.

6. Metabolic acidosis should be prevented or treated with sodium bicarbonate (1-2 mmol/kg).

7. In pregnancy, the outcome is satisfactory in patients whose ventricular function is good, and in whom no residual shunt occurs. However, close observation should be undertaken by an experienced team.

8. Venesection for erythrocytosis that is associated with cyanotic congenital heart disease should only take place if there are symptoms of hyperviscosity with a hematocrit >65%, and only provided volume replacement takes place at the same time.

9. Avoid muscle relaxants with histamine release e.g. atracurium, and use cisatracurium or rocuronium.

9. Mechanical ventilation:

-Increase FiO2

-Avoid increased airway pressure (< 15 cmH2O)

-Increase respiratory rate

-Avoid PEEP

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 Eisenmenger’s Syndrome

-A rare syndrome of pulmonary hypertension associated with a reversed or bidirectional cardiac shunt, occurring through a large communication between the left and right sides of the heart. The defect may be interventricular, interatrial, or aortopulmonary.

-The development of Eisenmenger’s syndrome, from the initial left to right shunt, is usually a gradual process. Contributory factors to pulmonary hypertension are hypoxia, high pulmonary blood flow, and high left atrial pressure.

-Irreversible structural changes take place in the small vessels, causing pulmonary vascular obstruction and a reduction in the size of the capillary bed. The pulmonary artery pressure is the same as or sometimes exceeds, the systemic arterial pressure.

-The incidence of this syndrome is decreasing because of the more vigorous approach to diagnosis and treatment of congenital heart disease in childhood.

Preoperative Findings:

1. Presenting symptoms include dyspnea, tiredness, episodes of cyanosis, syncope, or chest pain. Hemoptysis may occur.

2. The direction of the shunt, and hence the presence or absence of cyanosis, depends on several factors. These include hypoxemia, pulmonary and systemic pressure differences, and intravascular volume. It can also be affected by certain drugs.

3. Sleep studies have shown that there is a nocturnal deterioration in arterial oxygen saturation, which seems to be related to ventilation/perfusion distribution abnormalities occurring in the supine position.

4. Chest X-ray shows right ventricular hypertrophy, and ECG indicates varying degrees of right ventricular hypertrophy and strain.

5. Complications include thrombosis secondary to polycythemia, air embolus, bacterial endocarditis, gout, cholelithiasis, and hypertrophic osteoarthropathy. A cerebral abscess may occur secondary to clot embolism.

Anesthetic Problems:

1. Reductions in systemic arterial pressure by myocardial depression or loss of sympathetic tone are potentially dangerous. Reversal of the shunt may occur, and sudden death has been reported.

Hypovolemia and dehydration are poorly tolerated. Syntocinon may cause a dramatic reduction in SpO₂ secondary to vasodilatation.

2. Sinus tachycardia results from exercise or emotion, and episodes of SVT are common after the age of 30. The onset of atrial fibrillation is associated with a sudden deterioration in the condition of the patient.

3. General anesthesia tends to be favored since the reduction in systemic vascular resistance associated with regional blockade increases the shunt. However, successful use of epidural anesthesia for bilateral inguinal herniorrhaphy, and Cesarean section, have been reported.

4. Pregnancy is contraindicated because it carries considerable risks. Recent maternal mortality rates of 40% have been reported. A cesarean section may increase it to over 60%. Termination of pregnancy is usually recommended in the first trimester but is still associated with a mortality of 7%.

5. Patients are at risk from paradoxical air or clot embolism, and infective endocarditis.

Anesthetic Management:

1. Understanding the pathophysiology of the complex is essential, and both pregnancy and non-cardiac surgery require a multidisciplinary approach.

2. Maintenance of an adequate circulating blood volume is important. Myocardial depressants and peripheral vasodilators should be used with caution. Bradycardia must be prevented. If regional anesthesia is used, the block should be instituted with caution, and hypovolemia avoided.

3. It is unclear whether oxygen can cause pulmonary vasodilatation. Although the pulmonary vascular resistance was believed to be fixed in pulmonary hypertension, a high oxygen concentration has been shown to reduce it during cesarean section.

4. Maintenance of systemic vascular resistance is critical. The use of a norepinephrine infusion before induction has been described. Alpha-adrenergic vasopressors, such as methoxamine or phenylephrine, have also been used for the treatment of hypotension on induction of anesthesia.

5. Pulmonary ventilation should be performed with low inflation pressures and early tracheal extubation is advised, because of the deleterious effects of IPPV.

6. Air must be completely eliminated from all intravenous lines and the epidural space should be located with loss of resistance to saline, not to air.

7. Antibiotic prophylaxis against bacterial endocarditis.

8. Low-dose heparin may reduce the risk of emboli.

9. Patients are usually advised against pregnancy. If anesthesia is required either for termination of pregnancy or operative delivery, intensive cardiac care is indicated. It has been suggested that those reaching the end of the second trimester should be admitted to the hospital until delivery and given heparin 20000-40000 units daily and oxygen therapy. Successful epidural anesthesia has been reported for cesarean section.

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 Goodpasture’s Syndrome

-A rapidly progressive syndrome of glomerulonephritis and pulmonary hemorrhage, in association with antibodies to glomerular basement membrane (anti-GBM) type IV collagen, detectable in plasma by radioimmunoassay and by immunofluorescence techniques on muscle biopsy.

-These antibodies cross-react with the alveolar basement membrane, although those individuals with lung hemorrhage are usually smokers, and those with isolated anti-GBM nephritis are non-smokers.

-The term is often applied more loosely, to any disease with pulmonary hemorrhage and glomerulonephritis, whether or not anti-GBM antibodies are present.

-Systemic vasculitides such as PAN and Wegener’s granulomatosis cause lung hemorrhage and renal failure, but without the antibodies.

Preoperative Findings:

1. Patient presents with cough, dyspnea, hemoptysis (that can be massive), and anemia.

2. The pulmonary lesions proceed to interstitial fibrosis, with hemosiderin deposits. Lung function tests show a restrictive type of abnormality.

3. Glomerulonephritis, which usually follows or coincides with pulmonary lesions, may produce proteinuria, hematuria, and casts. The end result is renal failure.

4. Treatment may be with corticosteroids (prednisone) for pulmonary hemorrhage, cytotoxic drugs (cyclophosphamide) to stop renal damage, and plasmapheresis to remove antibodies.

Anesthetic Problems:

1. Poor respiratory function with hypoxemia and respiratory alkalosis.

2. Pulmonary hemorrhage that may, on occasion, be life-threatening.

3. Impaired renal function and sometimes renal failure.

4. Hypochromic anemia and a high ESR.

5. Patients may be receiving immunosuppressives or steroids, or undergoing plasma exchange, to reduce the antibody titer. Plasma exchange may reduce levels of plasma cholinesterase.

Anesthetic Management:

1. Preoperative assessment of lung function and, in particular, blood gases. Elective pulmonary surgery should not be undertaken during periods of active hemorrhage.

2. Assessment of renal function and appropriate management.

3. The management of a successful pregnancy has been described. It requires regular assessment of pulmonary and renal function. The use of steroids was associated with hyperglycemia, which needed treatment with insulin. Plasmapheresis was required.

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Gilbert’s Disease

Gilbert’s Disease (Idiopathic Unconjugated Hyperbilirubinemia)

-An autosomal dominant, benign condition, in which there is a mildly elevated unconjugated bilirubin, without either structural liver disease or hemolytic anemia.

-It possibly results from an impaired uptake and conjugation of bilirubin, secondary to a deficiency of UDP glucuronyl transferase.

-The diagnosis is made on a level of unconjugated bilirubin of 17–102 mmol/l, alternatively, a serum total bilirubin of 25–50 mmol/l after a 24-h restricted diet.

Preoperative abnormalities:

1. Serum unconjugated bilirubin is increased, but usually to a level <50 mmol/l, and clinical jaundice is barely detectable. However, fluctuating mild jaundice may occur, particularly in the presence of stress, infection, starvation, or surgery.

2. Other liver function tests are normal, and there is no hemolytic anemia.

Anesthetic Problems:

1. The condition itself is of no significance. However, the appearance of jaundice postoperatively may suggest more serious problems, therefore the confirmation of Gilbert’s syndrome as the cause is useful.

2. Starvation may elevate the bilirubin level and produce visible jaundice.

3. The metabolism of morphine, and papaveretum, may be delayed.

4. There are potential toxicological implications for any drug or chemical that is eliminated primarily via glucuronidation mechanisms such as paracetamol.

Anesthetic Management:

1. If Gilbert’s disease is suspected, the administration of nicotinic acid 50 mg IV will double or triple the plasma unconjugated bilirubin within 3 h. In normal patients, or in those with other liver diseases, the increase will be less.

2. Morphine, papaveretum, and paracetamol should be used with caution.

3. Early morning surgery and a dextrose infusion will reduce the increase in bilirubin provoked by starvation.

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 Hydatid Disease

-Hydatid cysts are the larval stage of the tapeworm, Echinococcus granulosus.

-Dogs are the main hosts. Man and sheep are intermediate hosts.

-Hydatid disease is not uncommon amongst the mid-Wales farming communities, and up to 26% of farm dogs in this area have E. granulosus.

-The incidence is also high in some regions of the Mediterranean, North Africa, the Middle East, and Australia.

-If the ova are ingested by man, embryos are released when the chitinous coat is digested.

-These enter the liver by the portal vein. They may be destroyed, or they may develop into a cyst.

-In man, the cysts are found in the liver (65%), lung (25%), muscles (5%), bone (3%), and brain (1%). Each cyst is two-layered and contains straw-colored fluid in which there are free scolices, brood capsules containing scolices, and daughter cysts.

-Around the cyst is an area of compressed host tissue and fibrosis known as the pericyst. In 5–10% of cases, the cyst will die, and calcification may occur.

Preoperative Findings:

1. Hepatic cysts occur most frequently in the right lobe. A bacterial infection may result in a liver abscess. Rupture into a bile duct, or bile duct obstruction can occur and produce biliary colic. There may be jaundice. The number and location of the cysts are shown on a CT scan or ultrasound.

2. Pulmonary cysts can present with hemoptysis, dyspnea, cough, or chest pain. Chest X-ray may show a variety of appearances including an oval opacity, evidence of bronchial fistula formation, or rupture of the cyst with the development of a fluid level.

3. Eosinophilia occurs in about 30% of cases. The Casoni skin test is still used for screening. Immunoelectrophoresis is the most specific test. The complement fixation test is positive in up to 80% of cases. The hemagglutination test detects a specific antibody.

Anesthetic Problems:

1. Pulmonary hydatid cysts can cause bronchial obstruction, and occasionally they may rupture into the airway. If this happens, flooding of the lungs occurs, with widespread dissemination of the scolices.

2. Hydatid fluid is highly antigenic, and the rupture of a cyst has occasionally produced sudden death from an anaphylactic reaction. Anaphylaxis to hydatid was confirmed by increased serum histamine and tryptase levels, with elevated levels of total and echinococcus-specific IgE antibodies.

3. Patients can develop anaphylaxis of unknown origin as interventricular hydatid cystic mass.

4. Cerebral cysts can cause increased intracranial pressure.

5. Scolicidal agents are potentially toxic and their use in combination with surgery may increase the complication rate.

6. Postoperative complications following surgery for hydatid cyst of the lung included prolonged air leak and aspiration pneumonia.

Anesthetic Management:

1. Surgical removal is indicated, except in older patients with small cysts. Meticulous care must be taken to avoid the rupture and spread of the fertile scolices.

2. Relatively new drugs, such as mebendazole and albendazole, are being tested as scolicidal agents. However, there is no evidence that they are effective in the treatment of pulmonary hydatid.

3. Pulmonary cysts. Protective formalin-soaked packs are placed around the wound, an incision is made through the pericyst, and the cyst is carefully extruded by the anesthetist, using gentle hand ventilation.

4. Because of the risk of an anaphylactic reaction, epinephrine (adrenaline), metaraminol, isoprenaline, and steroids must be immediately available.

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 Coarctation of Aorta

-A congenital narrowing of the aorta that may be pre- or post-ductal.

-The preductal form is usually a long, narrow segment, and is associated with other cardiac defects. This type generally presents with heart failure before the age of 1 year and requires treatment in a pediatric cardiac surgical unit.

-The postductal form, however, is often asymptomatic, and the patient may present in later life for surgery of some other condition, or for correction of the coarctation itself. Even after correction of coarctation, abnormalities can continue.

-Those who have undergone repair show persistent alterations in left ventricular function and left ventricular mass, together with resting gradients between the arm and leg. There is a higher incidence than normal of ischemic heart disease and sudden death.

-The optimal time for repair is disputed. Hypertension is more common in late correction, but repair at a young age is associated with a higher risk of recoarctation. In addition, persistent abnormalities in aortic stiffness have been found.

-Adult repairs are associated with a higher incidence of significant aortic valve disease (58%), compared with 37% of those repaired in childhood.

Preoperative Findings:

1. There may be moderate hypertension, the arm blood pressure being higher than that in the leg. If the left subclavian arises at or below the constriction there may be an absent or reduced left radial pulse. If both radial and femoral pulses are felt together, the small volume and delay of the femoral pulse will be obvious.

2. Collateral circulation develops in the internal mammary, intercostal, and subscapular arteries. The latter may be seen if the scapula is illuminated from the side.

3. A systolic murmur is usually heard along the left sternal edge radiating up into the neck.

4. Chest X-ray may show notching of the undersides of the ribs, secondary to intercostal arteries dilatation. There may be pre-and post-stenotic dilatation of the aorta.

5. Occasionally, cerebral berry aneurysms coexist with coarctation. In such cases, the high arterial pressure increases the risk of subarachnoid hemorrhage.

6. There is a 25–50% incidence of the bicuspid aortic valve and some aortic regurgitation.

7. Unusually, angina or left ventricular failure may present late in untreated adult coarctation.

8. Patients may require balloon dilatation or surgical resection.

Anesthetic Problems:

1. Before elective surgery, if undiagnosed coarctation is found, treatment of the coarctation may be considered to be the priority. Even if coarctation has been treated, the possibility of residual cardiovascular abnormalities should be considered, since there is an increased risk of premature death compared with the normal population. Causes include aneurysms (cerebral, at the operative site, other parts of the aorta and intercostal arteries), hypertension, myocardial infarction, and cardiac failure. Balloon angioplasty may carry less risk.

2. Patients may present with hypertension-related complications.

3. Any operation in the area of the dilated collateral vessels may result in heavy bleeding, especially when the chest is opened.

4. Hypoperfusion of the spinal cord. This may cause paraplegia, and is more likely in those patients with few collaterals. Induced hypotension for clipping of cerebral aneurysms may compromise spinal cord perfusion.

5. Susceptibility to bacterial endocarditis.

6. If there are left subclavian abnormalities, the left arm cannot be used for blood pressure monitoring.

7. Patients may present during pregnancy with hypertension, which may be confused with preeclampsia.

Anesthetic Management:

1. Antihypertensive therapy should be used until the day of operation. Beta-adrenoceptor blockers may reduce the hypertensive response to intubation.

2. Antibiotic prophylaxis against bacterial endocarditis.

3. During clipping of an intracranial aneurysm, monitoring of the femoral artery pressure should be undertaken to assess spinal cord perfusion during induced hypotension. A mean distal aortic pressure above 50 mmHg has been suggested as adequate for spinal cord perfusion.

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