By Y. Nerusul. Lewis University.
A study conducted 188 Comprehensive Surgical Management of Congenital Heart Disease generic 3.03 mg yasmin overnight delivery, Second Edition 10 versus 34°C cheap yasmin online american express, p < 0 yasmin 3.03 mg lowest price. The number of (a) rolling leukocytes and (b) adherent leukocytes was signifcantly less at 15°C relative to 34°C purchase genuine yasmin. Higher bypass temperature correlates with increased white cell activation in the cerebral microcirculation. In retrospect, this appears to have been related to a failure to abolish shivering because of use of an inadequate level of anesthesia in studies that were undertaken before 1950. The effect of temperature on cerebral Hypothermia was not used in the early years of metabolism and blood fow in adults during cardiopulmonary cardiopulmonary bypass. Current day rate that occurs with hypothermia has several important con- bypass hardware is very much more reliable so that the safety sequences for the cardiac surgical team. Nevertheless, the skill and experi- Safety Margin for Acute Pump, Oxygenator, Circuit or ence of the perfusion team in dealing with an acute prob- Cannula Failure In the early years of cardiopulmonary lem must be considered. Even today, clamps can be placed bypass, hypothermia provided an important safety element. Conduct of Cardiopulmonary Bypass 189 Improved Myocardial Protection Hypothermia reduces complete cessation of bypass, i. Although local myocardial hypothermia of perfusion fow rate evolved slowly and somewhat surrep- can be attained through infusion of cold cardioplegia solu- titiously entered into clinical cardiac surgical practice. One tion, the temperature of the pump perfusate has an important of the most important reasons for the slow acceptance of effect on the rate of rewarming of the heart between car- reduced fow rate with hypothermic bypass is a consequence dioplegia infusions (Fig. Even when there is total cardiopulmonary bypass with separate caval cannulas and • Improved intracardiac exposure. Many patients tourniquets, the temperature of retrocardiac tissues in par- with congenital cardiac anomalies, particularly ticular will be determined by perfusate temperature and will those which result in cyanosis, will develop mul- affect the rate of myocardial rewarming. Although multiple tiple profuse collateral vessels which increase the infusions of cardioplegia solution are well tolerated beyond left heart return. This blood fow usually returns infancy, many studies have suggested that in the neonate and to the left atrium through the pulmonary veins, younger infant, multiple reinfusions of cardioplegia result in but when the pulmonary artery is open it will also less good myocardial protection, most likely because of myo- result in continuous back bleeding from the pulmo- cardial edema. When excellent intracardiac expo- sure is necessary, it is often important to reduce the Decreased Metabolic Rate Allows Reduced Flow Rate: amount of left heart return temporarily. This can be Advantages Although it was recognized early in the his- achieved very effectively by reducing the perfusion tory of cardiac surgery that hypothermia would allow fow rate. Although left heart venting systems are available, it is often diffcult in the very small heart to achieve excellent exposure by venting all the left 35 heart return back to the pump circuit. As noted above, hypothermia per se reduces the infammatory effects of bypass, includ- ing both cellular activation and reduced activation of many humoral cascades. Although it has not 20 been well documented, it seems probable that an increased perfusion fow rate results in a greater degree of activation of both the cellular components of blood, as well as humoral cascades. The fgure fore highly probable that the use of a reduced fow illustrates mean cardiac septal temperature in neonatal pigs. J Thorac ies have demonstrated that the number of gaseous Cardiovasc Surg 1988;86:414–22. Because fat has a Membrane oxygenators can also produce multiple relatively poor blood supply, obese patients require longer gaseous microemboli if air is being entrained by the periods of cooling and rewarming than patients with a lean venous cannula and this effect is worse at high fow body mass. The higher ratio of surface area to body sible for most of the particles introduced into the mass in babies optimizes the effectiveness of water and air bypass circuit. Babies necessitate greater volumes of cardiotomy return also tend to be relatively low in total adipose tissue relative during open extracardiac procedures. A longer duration of cardiopulmonary bypass will result in a greater aggregation of the deleterious effects of cardio- Decreased Metabolic Rate Allows Reduced Flow Rate: pulmonary bypass, almost all of which are time related in Disadvantages The principal disadvantage of low fow their degree of severity. In their landmark textbook, Kirklin and Bleeding Barratt-Boyes attempted to develop a nomogram which It is generally considered that use of hypothermic bypass broadly indicates fow rates that may be safe at specifc tem- increases the probability of postoperative bleeding. The different effects of normothermic and for monitoring the safety of cardiopulmonary bypass both in hypothermic bypass on platelet function have not been well the past and currently remain quite inadequate. Furthermore, use of aprotinin and antifbri- patient temperature, pH and hematocrit have a strong infu- nolytic agents can be effective in reversing the deleterious ence on safe minimum fow rate as will be discussed later in effects of bypass and hypothermia on platelet function and this chapter. Disadvantages of Hypothermia Prolongation of Cardiopulmonary Bypass Infection Use of a more severe degree of hypothermia, i. The exact duration of cooling and well documented that transient exposure to hypothermic rewarming is determined both by the temperature gradients bypass results in a greater incidence of postoperative infec- employed between the water and the heat exchanger, blood tion relative to the use of normothermic bypass. The crosses mark appropriate clinical perfusion fow rates which allow a reasonable margin of safety for the indicated tempera- ture. Proteins provide most of the bypass often results in patients returning to the intensive body’s buffering capacity. It is the imidazole moi- care unit with a considerable heat debt and they often ety, which is found in the amino acid histidine, that is the principal buffer group of proteins. It has been well documented that this prolongs the duration of intubation, as is widely found in plasma proteins and importantly well as total recovery time, in the intensive care unit. Thus red cells, as well as plasma, neonates and infants who can be more effectively warmed have an essential buffering function that is reduced by surface means than adults and who appear in general to by hemodilution. However, just as is the Normal Physiology of Carbon Dioxide and pH case with imidazole, red cells also play an important role in bicarbonate buffering. They achieve this by Vasomotor Effects: Systemic Vasodilation, containing carbonic anhydrase. Carbonic anhydrase Pulmonary Vasoconstriction facilitates conversion of carbonic acid to carbon Carbon dioxide is a powerful systemic vasodilator and dioxide and water thereby preventing accumulation conversely alkalosis and a low carbon dioxide level cause of carbonic acid through subsequent exhalation of systemic vasoconstriction. Patients suffering an acute anxiety attack through respiratory changes and bicarbonate levels through can hyperventilate to the point that their carbon dioxide level renal excretion, the bicarbonate buffer is a critically impor- falls so low that cerebral vasoconstriction results. This situation can be remedied by rebreathing in a paper bag Carbon Dioxide and pH during to raise the patient’s carbon dioxide level, thereby restor- Cardiopulmonary Bypass ing adequate cerebral blood fow. The interpretation of the Cardiopulmonary bypass places the control of acid-base direct vasomotor effects of carbon dioxide is complicated by in the hands of the perfusion team and overrides the many the sympathetic response that results from hypercarbia and homeostatic mechanisms that function during normal physi- respiratory acidosis, which may cause sympathetic vasocon- ology. It is also important to remember that the effects an important impact on acid-base balance. Thus if Flow Rate there are connections between the systemic and pulmonary Tissue acidosis with a subsequent fall in blood pH will result circulation, such as aortopulmonary collaterals or a systemic if the fow rate is inadequate to maintain tissue oxygenation. It is important to remember that this the distribution of fow between the systemic and pulmonary is between a half and two thirds of a normal physiological vascular beds. Acid-Base Balance Dilution Maintenance of a stable intracellular pH at close to the pH The contribution to buffering of the nonbicarbonate buf- of neutrality of water (pN) is essential for optimal enzyme fers (the imidazole groups of the proteins contained within function. In order to maintain ity expressed as the titration of a specifc amount of acid intracellular pH at this point, extracellular pH is maintained or alkali added to a closed system and causing a change in humans between 7. The unit of this measurement is called the the actions of a number of buffer systems. If a crystalloid solution is used N as the bypass prime, the consequent dilution of the patient’s H+ blood will result in a signifcant reduction in the nonbicar- 7. Erythrocyte dilution to a hematocrit of 20%, associated with the same degree of plasma dilution, results in a decrease in buffer strength of approximately 61 7. If the hematocrit is reduced to between 24 and 28% dur- ing bypass, this will result in a 20% reduction in nonbi- carbonate buffering. Hypothermia Phosphate As noted earlier in this chapter, the pH of water increases 6. Another way of expressing this fact is that the pH of neutrality (pN) rises with hypothermia. The pH which is read from the machine can be temperature corrected to a 0 10 20 30 40 body temperature of X°C by the formula: Temperature (°C) pHxºC = –pH37°C + (37 – x)(0. Because the imidazole moiety It is interesting to note that the fact that the slope of the of the amino acid histidine in proteins performs the bulk of buffer- change in pH with temperature of whole blood is similar to ing in blood, the slope of the dissociation constant for blood is simi- that for neutral water refects the dominant role of imidazole lar to the slope of the dissociation constant for water. The importance of acid-base man- stant (pK) for imidazole is very similar to the dissociation agement for cardiac and cerebral preservation during open heart constant for water (Fig. The pH of neutrality of blood retains during Cardiopulmonary Bypass its usual alkalinity relative to intracellular pH so that there Ectothermic (“cold-blooded”) animals and hibernating mam- is a constant hydrogen ion concentration gradient between mals have provided an opportunity for study of the alternative the intracellular and extracellular environments both at nor- methods whereby different species adjust their physiology mothermia and hypothermia. Interestingly dif- temperature allows these animals to maintain a constant ratio ferent strategies have evolved for species that must remain of hydrogen to hydrogen ions across a wide range of tempera- active while hypothermic versus those that hibernate. They are faced with the problem “alpha”) of dissociated to nondissociated imidazole groups of needing to be able to mobilize energy stores effciently remains constant with this strategy. They achieve optimal energy mobilization by maxi- Hibernators and the pH Stat Strategy mizing enzyme effciency.
Most women with aphthous ulcers lence of anti-infammatory cytokines 3.03 mg yasmin overnight delivery, and enhanced are otherwise healthy with no other pathological interleukin-17 production in affected individuals purchase yasmin with paypal. British study reported that 51% of women with pem- Aphthous ulcers are a predominant feature of phigus vulgaris had lesions in their genital tract discount yasmin 3.03mg amex. Antibody recognition of these proteins triggers oral ulcerations discount 3.03 mg yasmin with visa, uveitis, and neurological, vas- neutrophil recruitment, activation of the comple- cular, pulmonary, and articular manifestations ment cascade, and the release of proteases that initi- in some individuals. The disease triggers for development of this specifc autoimmu- is rare in the Americas and Europe and is most nity in susceptible individuals include several mem- common in Turkey, the Middle East, and the bers of the herpesvirus family as well as exposure to Far East. Often the patients have a history of skin triggered that results in the appearance of clini- disorders on other parts of their bodies. Interestingly, the concentration of mation will be gained from the history, and other a minor subset of T lymphocytes, gamma delta T affected areas need to be examined before evaluat- cells, is increased in the circulation of individuals ing the vulva and vagina. The pelvic examination is with either recurrent aphthous ulcers or Behçet’s diffcult for many reasons. Gamma delta T cells recognize, prolifer- confusion is the reality that some common derma- ate, and produce pro-infammatory mediators in tologic disorders have a different gross appearance response to hsp60, lending further support to the on the cornifed epithelium and mucous membranes suggestion that hsp60 might be a target antigen for of the vulva than they do on other cutaneous sites development of autoimmunity leading to aphthous on the body. Very recent investigations have also genital tract disorders can come from a thorough noted the involvement of natural killer cells13 and examination of other skin and mucous membrane the pro-infammatory cytokine, interleukin-33,14 surfaces. These women require a thorough, head-to- as contributing to Behçet’s disease symptomatol- toe physical examination. Since pregnancy favors the predominance of a humoral immune response and inhibition of cell-medicated immunity, it was of interest to flaking skin DisorDers determine the effect of pregnancy on Behçet’s dis- Atopic dermatitis (lichen simplex chronicus) is the ease manifestations. No consistent response was most frequent skin affiction found in these symp- observed. They are uncomfortable all of became worse in others, and remained the same in the time, particularly at night, and present with a third group of patients. A simple but Vulvovaginal Infections 152 helpful question for these sufferers is as follows: A portion of the sample should also be sent for fun- “is the itching on the outside or in the vagina? These altered vulvar surface areas are Further questioning is needed to determine if these prone to infection, and the resulting infammation women have an allergic history, including seasonal from infection exacerbates the itch–scratch–itch or skin allergies. Either a local antifungal azole or oral fuco- ment of this disease or exacerbation of symptoms nazole can be prescribed for these women who are include psychological stress in the workplace or at culture positive. Magnifcation of these lesions with home and local environmental factors such as heat, a colposcope is an aid in evaluation, and an attached sweating, or excessive dryness. Too often, the general pathology and occasionally a mucosal contact dermatitis to the report will be nonspecifc. The general pathologist’s propylene glycol in the locally applied antifungal main purpose is to determine whether a cancer or creams makes the situation worse for these patients, precancer is present. In contrast, the dermatopathol- ination, these women have an infamed, irritated ogist will establish the diagnosis of atopic dermatitis vulva with demarcated thickened skin, the result if present, and on occasion other unexpected skin of frequent rubbing or scratching (Figure 14. The obvious result of scratching is denied by many patients, ill at ease with the thought that they had Psoriasis been scratching their pubic area, a response they This skin disorder has a recognized appearance with consider to be socially unacceptable personal behav- plaques on cornifed epithelial sites elsewhere on the ior. If there is a white surface exudate on the infamed, It is an ailment in which symptoms usually worsen thickened vulvar skin, a gentle scraping of the vulvar in the winter and improve in the summer. On the vulva, the skin changes do not include the promi- nent plaques of psoriasis seen elsewhere on the body (Figure 14. These gross physical fndings need to be followed by a vulvar biopsy, with the specimens sent to a dermatopathologist so that a defnitive diagnosis can be obtained. History was positive for asthma, hay fever, bertal children, but it is more commonly seen in and eczema. The dom called upon to examine children, this is a con- condition responded to twice daily application of dition usually seen in women over the age of 50. The patient was treated with four oral doses of 150 mg fuconazole, given every 4 days. Posttreatment, there was less adherent white exudate on view, no hyphae were present on microscopic examination, and the culture grew no C. The The underlying skin changes of lichen sclerosus were patient also had psoriasis involvement of the elbows. These early changes of lichen sclerosus can be improved with the use of a These women complain of dyspareunia, dysuria, or local steroid ointment. Over time, in women who do not seek a medical evaluation, the untreated vulvar skin can assume a variety of abnormal appearances. The patient can develop parchment-like skin, extending into the perirectal region. In con- trast, the skin can assume a grossly white hue with a wrinkled appearance (Figure 14. This vulvar skin is less malleable and more prone to fssure for- mation (Figure 14. There can be similar lichen sclerotic lesions in other body sites, but usually these skin changes are limited to the vulva. Access to a dermato- confrmed by biopsy, seen early in the course of the pathologist is again crucial so that an appropriate disease. Overall, atrophic parchment-like skin with a sclerosus with dysuria and vulvar itching. The patient also had a painful chronic buccal erosion with a white lacy margin and a line of erythema at the base of her teeth. Three months of full-dose azathioprine (Imuran) restored normal anatomy and pubic hair with signifcant varicosities on the perineum as the only residual. A biopsy is required to make the The infammatory skin disorder lichen planus has diagnosis and should be taken from the edge of the different clinical presentations depending upon the lesions. On keratinized skin, it presents as pruritic quantifying the massive plasma cell infltrate and papules. It is a bright red eczematoid lesion ful and sometimes bloody, precluding any attempt at on the vulva. On the basis of a pathologic diag- ited to the vulva and can involve other mucous mem- nosis, patients can be divided into four groups: (a) branes, including the vagina and the oral mucosa. If intraepithelial Paget’s disease, (b) invasive Paget’s lichen planus is suspected, a thorough examination disease, (c) intraepithelial Paget’s disease with an of the oral cavity is indicated as well. If untreated, underlying adenocarcinoma, and (d) intraepithelial these lower genital tract lesions can result in scarring Paget’s disease with a coexisting cancer in either the and atrophy, with extreme narrowing of the introi- genitourinary tract, the breast, or the skin. This is yet another situation in possibilities need to be kept in mind in the general which a biopsy sent to a dermatopathologist will be physical examination of these patients, plus the need invaluable. In planning the biopsy site, if there is for imaging studies and other site biopsies in some of an erosion, the biopsy should be obtained from the these patients. Occasionally, the vulvar biopsy is Patients with pemphigus initially related peri- not defnitive. When this occurs, the patient should ods of vulvar itching that precede the appearance be referred to an oral surgeon for evaluation and of a vulvar blister. This may be months of persistent entry dyspareunia in a post- distinguished from vulvar pemphigoid and Behçet’s menopausal patient. Patches of erythema circum- disease by biopsy, with a segment of skin tissue sent ferentially in the area of the vestibule were painful for immune staining. Associated purulent vaginal reveal posterior chamber infammation in the cases of discharge, characterized by numerous white blood Behçet’s disease. The patient responded slowly to disease classifed among the vasculitides and not medium-strength topical steroid ointment. Posterior uveitis does occur as well as a wide spec- are present, traction on the skin will allow them to trum of vasculitic lesions. Instead, lying pathology of the loss of adhesion of the epi- it has to be based upon clinical fndings. This with routine microscopy and direct immunofuores- diagnosis should be considered as a possibility in cence. A general physical examination is important, a patient whose family roots are in the geographi- for these patients will have oral mucosal lesions and cal areas mentioned earlier. Adolescent girls usually have an abrupt pre- criteria of Behçet’s disease sentation. Many of these women will have oral herpetiform) observed by the physician or lesions as well. Eye lesions: anterior uveitis, posterior uveitis, biopsy of the edge of the ulcer should be obtained cells in the vitreous by slit lamp examination when the ulcer recurs. A dermatopathologist can do or retinal vasculitis observed by an immunochemistry on the biopsied tissue to confrm ophthalmologist the diagnosis of aphthous ulcers. Skin lesions: erythema nodosum, Another uncommon problem is Behçet’s dis- pseudofolliculitis, papulopustular lesions, or ease.
Despite the obstacles cheap yasmin on line, the future is bright for approach along with a reliance on volatile anesthetics cheap 3.03mg yasmin fast delivery. A proposal for or upon rewarming buy 3.03mg yasmin with mastercard, and at least 1 minimum alveolar concen- training in pediatric cardiac anesthesia yasmin 3.03mg with mastercard. Anesth Analg tration equivalent of volatile agent provided for the duration 2010;110:1121–5. Beginning a career in pediatric car- of fentanyl given (5–25 μg/kg) for the entire case and rely diac anesthesia: up the creek, but where’s the paddle? Paediatr heavily on volatile anesthetic agents along with shorter act- Anaesth 2007;17:407–9. Congenital heart disease and anesthesia- cotic during intraoperative management has been described. Anesth Anaesth Regional techniques such as caudal morphine (50–75 μg/kg) 56 2010;110:1255–6. The frequency Dexmedetomidine, a selective central α2-agonist, has of anesthesia-related cardiac arrests in patients with congeni- become widely used in pediatric anesthesia because it has tal heart disease undergoing cardiac surgery. Anesth Analg anxiolytic, hypnotic, and analgesic properties without caus- 2007;105:335–43. Cost in patients with renal or hepatic failure, heart block, hypo- effectiveness analysis of anesthesia providers. Preoperative and postoperative anes- surgery to facilitate timely extubation and to provide post- thetic assessment for pediatric cardiac surgery patients. Practice guidelines for preoperative fasting and the use of toddlers with single-ventricle physiology. At the Children’s pharmacologic agents to reduce the risk of pulmonary aspira- National Medical Center, we use a low-narcotic strategy (a tion: application to healthy patients undergoing elective proce- single bolus of fentanyl [25 μg/kg] prior to incision) along dures: a report by the American Society of Anesthesiologists with a volatile agent, followed by a single bolus of dexme- Task Force on Preoperative Fasting. Effects of ketamine child with congenital heart disease are made, the need for on the contractility of failing and nonfailing human heart mus- cles in vitro. More than ever before, the pediatric effects of anesthetic induction with ketamine. Anesth Analg cardiac anesthesiologist is recognized as a critical member of 1980;59:355–8. Pediatric cardiac fentanyl intravenous sedation in children: case report of respi- anesthesiology, as a specialty, is rapidly evolving and there ratory arrest. Bradycardia cialty training program and certifcation track for the next gen- during induction of anesthesia with sevofurane in children eration of cardiac anesthesiologists is imminently necessary. Scheduled autol- cerebral oxygen saturation thresholds for hypoxia-ischemia in ogous blood donation at the time of cardiac catheteriza- piglets. Physiol blood transfusion in pediatric patients undergoing open heart Meas 2007;28:1251–65. Transfusion-related mor- oxygenation in hypoplastic left heart syndrome after the tality: the ongoing risks of allogeneic blood transfusion Norwood procedure. J Thorac Cardiovasc Surg associated graft-versus-host disease in an immunocompe- 2005;130:1523–30. Comparative analysis of anti- pulmonary function in coronary artery bypass graft surgery fbrinolytic medications in pediatric heart surgery. J Thorac patients undergoing early tracheal extubation: a comparison Cardiovasc Surg 2012;143:550–7. The risk associated with and systemic cytokine release after cardiopulmonary bypass. Semin macokinetics of milrinone in neonates with hypoplastic left Thromb Hemost 2000;26:407–12. Chest hemostatic effects of fresh whole blood, stored whole blood, 2005;127:1828–35. Fresh whole refractory postoperative bleeding in children undergoing car- blood versus reconstituted blood for pump priming in heart diac surgery with cardiopulmonary bypass. Impact of dexmedetomi- ver from surgery to intensive care: using Formula 1 pit-stop dine on early extubation in pediatric cardiac surgical patients. Fast-track of children in the operating room after atrial septal defect congenital heart operations: a less invasive technique and early repair as part of a clinical practice guideline. Ann Thorac Surg macokinetics of dexmedetomidine in infants after open heart 2000;69:865–71. Fast-track paediatric cardiac surgery: the feasibility and benefts of a protocol for uncomplicated cases. Over the past two decades, there have been substantial Optimal intensive care management requires a thorough improvements in the mortality and morbidity associated understanding of the subtleties of complex congenital car- with the management of congenital heart disease. Equally important has been the systems and the transitional circulation of the neonate, and development of specialized pediatric cardiac intensive care an in-depth understanding of respiratory physiology and for the preoperative management of complex and challenging the signifcance of cardiorespiratory interactions. Because of the wide variation in patient demo- plex extracardiac congenital anomalies. The range of anatomic defects and the signifcant young children are not able to communicate their level of dis- pathophysiologic derangements that accompany congenital tress and discomfort. Pediatric cardiac intensivists often must heart disease mean that care should be proactive rather than rely on indirect clinical evidence from autonomic responses reactive. An experienced team will be able to anticipate a to stress, such as hypertension and tachycardia, and make particular clinical course, perceive an evolving clinical pic- careful judgments as to the level of pain relief or sedation. The safety, effcacy, and pharmacokinetics decreasing the length of intensive care stay as well as total of drugs are often different from what is seen in the adult hospital stay. This is particularly critical when establishing a cal intervention and survival are possible in younger and diagnosis and planning surgical intervention. Because of the unique and complex nature of and treat pulmonary hypertension will enhance subsequent their underlying defects and pathophysiology, these adults growth and development. In the early 1970s, few neonates of patients requires nurses and physicians who are accus- underwent cardiac surgical procedures and only a small per- tomed to caring for children to reset their scope of practice centage of these neonates underwent surgical repair using and recognize new triggers for concern and intervention. Early palliation or deferred surgery was the usual The defnition of hypotension and impending shock, the approach, and repair was undertaken in older children. Over need to recognize and respond quickly and effectively to the next decade and by the mid-1980s, there was a substan- massive blood loss, the conditions that predispose to renal tial change in approach such that surgery in neonates and insuffciency, the susceptibility of the lung to barotrauma infants became established practice. For example, a newborn with systemic ventricular outfow pathology associated with the disease itself or the repair. Furthermore, as neonatal mortality has signifcant impact on the early diagnosis and management decreased signifcantly, there is a growing population of of congenital heart disease. In addition, early interventions discuss the extremes of treatment options, sometimes even in such as balloon dilation of an intact atrial septum in patients circumstances that may not be applicable to a specifc patient. While it has been diffcult to establish a their care, as well as their memories of the end-of-life deci- sions. Furthermore, prenatal diagnosis ben- for physicians and nurses within the pediatric cardiac critical efts the families as well by allowing them time to be bet- care environment, and further highlight the importance of ter informed, emotionally equipped, and mentally prepared maintaining a high level of knowledge and experience on the for having a child with congenital heart disease and possibly part of staff to ensure coherent treatment plans. Physicians and nurses working in this environment than 85%) where intervention may be unnecessary. As part need to have experience not only in critical care, but also in of the understanding of the underlying cardiac defect and cardiology, cardiac surgery, and anesthesia. The full range physiology, it is essential that an appropriate range of oxy- of treatment modalities should be immediately available, gen saturation levels be maintained; often it is preferable for including respiratory support with conventional mechanical the patient to be cyanotic with good systemic cardiac output ventilation and high-frequency oscillatory ventilation, the as opposed to well saturated but in shock. The a lower than normal oxygen saturation secondary to pulmo- response to management strategies must be continually re- nary venous desaturation from parenchymal lung disease, evaluated and adjusted when necessary. Although early ing or mixing, and alterations in cardiac output or oxygen interventions and changes in management strategies may be delivery that have substantially lowered the mixed venous necessary, it is equally important to know when a patient is oxygen saturation. As a general guide, if patients are not progressing cardium, which leads to signifcant clinical and physiologic as expected and low output persists, cardiac catheterization differences when compared to older children and adults. The should be performed to investigate and exclude the possibil- time to achieve full maturation is variable and dependent on ity of undiagnosed or residual structural defects. The stroke volume is relatively fxed All aspects of these conditions may be different or exagger- and the myocardium less compliant because of the reduced ated in the newborn. The importance of loading condi- have a lower velocity of shortening, a diminished length–ten- tions, the contractile state, and the heart rate and rhythm are sion relationship, and a reduced ability to respond to after- all important factors. For example, if the neonatal myocardium is exposed compliance and reliance on the diaphragm as the main mus- to a signifcant volume load that causes stretch of myofbrils cle of respiration limits ventilatory capacity.
The direction it pushes the drainage pathway is the cells that are obstructing the frontal ostium can be re- primarily dependent on where the cell is based (anteriorly order yasmin toronto, moved (Fig best yasmin 3.03mg. An example of this anatomical variation struction performed buy yasmin discount, and drainage pathway determined purchase 3.03mg yasmin with mastercard. Note how the sinus drains anterior to the frontal bulla cell and then medial to the agger nasi cell. If the 3D picture is reviewed and the frontal sinus drain- age pathway is placed, a true 3D image of both the anat- omy and the pathway is formed. This allows planning of each step of the surgical resection of the frontal bulla cell (Fig. The agger nasi cell is proposed as the key to the understanding of this complex area. The surgeon should then go through the surgical Frontal Bulla Cell with Anterior Drainage Pathway steps to be performed. For example: create an axillary fap, (Video 21) raise the fap, remove the anterior wall of the agger nasi cell, place the curette medial or behind the agger nasi cell, This cell has been commonly confused with the T4 cell of the and remove this cell (medial wall and roof). Identify the re- original Kuhn classifcation in which a T4 cell was defned as sidual cells and the frontal sinus drainage pathway around an isolated cell within the frontal sinus. Place the suction curette along the frontal sinus numbered 1 appears to be an isolated cell in the frontal sinus. Such a sur- on the parasagittal scan, it is quite clear that this is a frontal gical plan, formulated from a thorough understanding of bulla cell that originated in the suprabullar space and pneu- the anatomy, allows a confdent dissection of a complex matizes forward along the skull base into the frontal sinus. Chronic frontal sinusitis: the endoscopic frontal recess The videos that accompany this book present a series of approach. Oper Tech Otolaryngol—Head Neck Surg 1996;7:222–229 case studies in which the variations described above are il- 15. Attempt to draw the anatomy of the Laryngoscope 2001;111(4 Pt 1):603–608 frontal recess using building blocks and establish a 3D pic- 16. Then scope 2002;112(3):494–499 review the video of the surgical procedure so that you can 17. Surgical techniques for the removal of frontal re- see how the anatomy seen in the dissection relates to your cess cells obstructing the frontal ostium. Laryngoscope 1997; 107(11 Pt 2):1–36 Surgical Approach to the Frontal Sinus 7 and Frontal Recess The frontal recess has always been considered to be the most the additional technique of frontal sinus mini-trephination difcult area to dissect. This technique has similarities to the fron- and associated transitional spaces (hiatus semilunaris and tal sinus rescue procedure described by Kuhn et al. However, the major diference is that the frontal maxillary sinus and associated transitional spaces will result sinus rescue procedure is designed for the management of in clearance of the frontal recess and sinus disease. The axillary fap technique is de- cations come from the same group of investigators. The broad spectrum of frontal sinus and frontal recess disease, central concept of the axillary fap procedure is removal of we do not advocate this approach. Close11 have advocated a similar approach with removal of Although we agree that surgery on a diseased frontal sinus or the bone above the insertion of the middle turbinate. The recess that is symptomatic is appropriate, we disagree that major diference between these approaches and the axil- this is the only indication for surgery in this region. Patients lary fap approach is the elevation of a mucosal fap which who present with nasal obstruction, postnasal drip, purulent can be replaced at the end of the procedure to cover the rhinorrhea and anosmia, and who have radiological disease raw exposed bone that is seen after removal of the anterior in the frontal sinus or recess need to have this region sur- wall of the agger nasi cell. These patients have their diseased maxil- from forming over the exposed bone with subsequent scar- lary sinuses, ethmoid, and sphenoid sinuses addressed and ring and cicatrization of this area. Such scarring can pull the it makes no sense that just because they do not have local- upper extension of the middle turbinate laterally and close ized frontal pain or tenderness, that the frontal sinus should of the anterior aspect of the frontal recess. It has been well recognized that lead to blockage of the frontal outfow tract and result in retained or residual cells in the frontal recess/sinus is one of recurrent frontal sinusitis. In the easy frontal of residual cells within the frontal recess with the exposure recess and sinus, simple maneuvers in terms of endoscopy of the frontal ostium is usually sufcient to achieve resolu- and surgical access (axillary fap) are advocated and are, in tion of frontal sinusitis. It is our philosophy that where pa- most cases, sufcient to allow clearance of the frontal recess tients have cells in the frontal recess or frontal ostium that and frontal ostium. In the difcult frontal recess or sinus, obstruct the outfow of the frontal sinus, that these should 81 82 Endoscopic Sinus Surgery be removed without enlarging the frontal ostium. Partial surgery of the frontal recess tunity to see if the natural size of their frontal ostium is suf- is never indicated. In some patients, especially those with severe mucosal removed or one of the frontal ethmoidal cells is removed, disease, this ostium may become edematous and obstruct scarring is likely to result. The cells in the frontal recess are and, if this causes symptoms, then enlargement of the ostium usually in close approximation and partial clearance of cells is indicated. However, this occurs in the minority of cases will very likely result in adhesions forming between these and it’s not possible to predict which patients with a par- closely approximated surfaces with obstruction of the drain- ticular frontal ostium size will obstruct and become symp- age pathway of the frontal sinus. Drilling in the frontal ostium without alone or all the cells are removed from the recess with visu- creation of the largest possible ostium is likely to result in an alization of the frontal ostium. As can be seen in Chapter 9, enlargement of the frontal ostium is usually done with a modifed Lothrop Assessing the Frontal Recess and procedure/Draf 3/frontal drillout and very rarely with a Draf Frontal Sinus Prior to Surgery type 2 (unilateral enlargement of the frontal ostium) proce- dure, due to the increased incidence of fbrosis and stenosis In a patient who is to undergo frontal recess clearance and seen with unilateral drilling on the frontal ostium. In this patient, after unci- nectomy and middle meatal antrostomy, an axillary fap is Which Patients Are Suitable for Frontal performed to expose the anterior face of the agger nasi cell. This is removed with the Hajek Koefer punch (Karl Storz, Tuttlingen, Germany) and the agger nasi cell visualized. The resultant debris is removed with a microde- recess and frontal ostium exposed (Fig. In this patient the left frontal recess would be 7 Surgical Approach to the Frontal Sinus and Frontal Recess 83 Fig. Note the space available to operate in the wide diameter dially around this cell and the suction curette is slid along patient. The fron- tal ostium is visualized but all mucosa around the frontal Single agger nasi cell is the simplest confguration in the fron- ostium is preserved. A simple cell confguration of one or two associated frontal ethmoidal cells is also relatively Identifying the Easy from the Difcult Frontal Recess easy to deal with in the frontal recess. The need for ensure that the drainage pathway of the frontal sinus is iden- computer-aided surgical navigation is assessed at the same tifed and instrumented. The surgeon should assess the degree of difculty allow adequate ventilation and drainage of the frontal sinus. Small Frontal Sinus with Poorly Pneumatized Agger Nasi Cells and Small Frontal Ostium Narrow versus Wide Anteroposterior Diameter of the This can be problematic if the frontal sinus is completely Frontal Ostium opacifed and the surgeon wishes to ensure the pus or inspis- sated mucus is cleared from the sinus. This refects the postoperative size cess and can increase the risk of scarring and adhesions in of the frontal ostium that can be achieved without drilling the frontal region. The small drainage pathway of the frontal sinus on the right is marked with a black arrow (B–D). This serves the Frontal Ostium two purposes as it keeps the frontal ostium clear of blood clot (which can contribute to fbrosis and scarring) and the New bone formation in the region of the frontal ostium and prednisolone diminishes the infammatory response in the recess often indicates osteitis of the surrounding bone. Re-stenosis Previous Surgery with Scarring of the Frontal Recess and obstruction of the frontal ostium will often result. Cultures of removed bone should be nate with lateralization of the remnant with associated scar performed and patients should then be started on appro- tissue formation, can make exposure of the frontal ostium priate antibiotics. This can be done by giving a 3-week course of new bone formation and endoscopy can confrm the pres- oral steroids. Alternatively, or in combination with the oral ence of scar tissue in the frontal recess. An example is shown steroids, the mini-trephine cannulas can be left in place for in Fig. In this example the patient has al- lergic fungal sinusitis with expansion of the frontal recess and double densities visible on soft tissue settings (white arrow). The frontal recesses in this patient were flled with highly vascular polyps and inspissated fungal material. Not only were the normal anatomical landmarks distorted in this patient but there was extensive bleeding in the frontal re- cess as the polyps were removed. As previously stated such vascularity can signifcantly increase the degree of difculty for the surgeon during removal of the polyps and cells, and during identifcation of the frontal ostium. The unci- scarring is seen between the lateralized residual middle turbinate and nate remains and abuts the retained anterior ethmoid cells obstructing lateral nasal wall (uncinate). The If there are polyps present, identifcation of the residual natural ostium of the sphenoid is usually 12 mm above the middle turbinate can be difcult (Fig. The microdebrider blade is 4 mm and to identify the maxillary ostium and to clear the maxillary this can be used to measure 12 mm from the posterior bony sinus of polyps using the maxillary trephination procedure if choanae. This will allow positive identifcation lary sinus which can be used as a guide to enter the sphenoid.