By N. Pyran. Northeastern Illinois University. 2019.
In summary roxithromycin 150mg line, there is reasonable clinical evidence that planned relaparotomy does not have a survival beneft compared to on-demand laparotomy based on several studies order 150 mg roxithromycin with mastercard, including one large meta-analysis discount roxithromycin 150 mg with amex. The open abdomen in abdomi- nal sepsis might be associated with increased mortality and a higher incidence of enteroatmospheric fstulae compared to relaparotomy on demand [37, 42–48]. On-demand laparotomy is associated with decreased costs and health-care use [47, 48]. Unfortunately, the studies dealing with this controversy demonstrate substantial variability, and therefore their conclusions are scrutinized with caution. Hemodynamics and the need for vasopressors support of the patients submitted to emergency surgery due to abdominal sepsis should guide the acute care surgeon to consider damage control and open abdomen techniques. High index of suspicion for proper diagnosis before the onset of organ failure and prompt treatment once the diagnosis is made will result in favorable outcome. The classic syndrome of cardiopulmonary and 5 Indications for Open Abdomen in the Non-trauma Setting 79 splanchnic abnormalities represents advanced stage, and surgical decompression should not be delayed until this stage is reached [59–62]. The head of the patient’s bed should be raised not more than 30 degrees, neuromuscular blockage should be administrated , and relief of pain and anxiety with proper medication should be initiated promptly . Prokinetic agents such as erythromycin and metoclopramide may help in avoiding paralytic ileus . Administration of loop diuretics to enhance fuid removal may be of ben- eft if patients’ hemodynamic allow its administration. Removal of fuid by extracor- poreal techniques is more effective and may have an immediate effect . Seven patients responded to nonoperative therapy, but the remaining 13 patients had progressive deterioration of organ dysfunction and received interventional decompressive procedure. The effects of abdominal decompression on organ functions were summarized in a collective review of 250 patients who underwent midline laparotomy [83, 85]. Decompression had a positive effect on hemodynamic, respiratory, and renal func- tion parameters. However, despite initial improvement almost in all patients, mortality rate of 50% was recorded. In another retrospective study, the mortality after various techniques of decompression was 46% . Different surgical techniques exist but currently there are no randomized trials comparing the outcomes of the different surgical approaches. Acute arterial occlusion is the most common cause of mesenteric ischemia and results from embolic occlusion in 40–50% and thrombotic occlusion in 20–35% of the patients . This policy includes a routine re-exploration of the abdomen 24–48 h after the index operation carried out in an effort to preserve as much bowel as possible. Some surgeons select aggressive approach with a scheduled second-look proce- dure in any patient who undergoes bowel resection and primary anastomosis [88, 89], whereas others suggest a more selective approach [90, 91]. Other researchers found that fewer than half the patients underwent a second- look operation and more than 40% benefted from the procedure that resulted appro- priate treatment. In mesenteric venous thrombosis, the thrombotic process extends well beyond what appears to be the compromised bowel. Therefore, a second-look exploration is often the only way to establish the full extent of nonviable bowel. In a nonrandomized case–control study , patients undergoing planned relap- arotomy were matched with patients who underwent relaparotomy on demand. There was no signifcant difference in mortality between the groups, but multiple organ failure and septic complications were more common in the patients who underwent planned relaparotomy. Second-look laparotomy may be avoided if the experienced surgeon identifes clear margins of demarcation between well-vascularized and necrotic bowel in a hemodynamically stable patient. Until large prospective studies are available, the indications for a second- look operation should be evaluated with caution and be based on surgeon experi- ence and based on the surgical fndings as well as patient hemodynamics. The strategy of leaving many patients with open abdomen was frst reported from the Mayo Clinic. Although many surgeons practice this approach in diverse abdominal pathologies, no common denominator can be outlined in the reported cohort. Only well-conducted studies based on internationally agreed nomenclature will address the issue of who will be the patient that will beneft from the open abdomen and damage control strategy. Packing and planned reexploration for hepatic and retroper- itoneal hemorrhage: critical refnements of a useful technique. Management strategies for the open abdomen sur- gery of the American Association for the surgery of trauma membership. Intra-abdominal hypertension and the abdominal compartment syndrome: updated consensus defnitions and clinical practice guidelines from the World Society of the Abdominal Compartment Syndrome. Indications for use of damage control surgery and damage control interventions in civil- ian trauma patients: a scoping review. Coccolini F, Biff W, Catena F, Ceresoli M, Chiara O, Cimbanassi S, Fattori L, Leppaniemi A, Manfredi R, Montori G, Pesenti G, Sugrue M, Ansaloni L. Three indications for the “open abdomen”, anatomical, logistical and physiological: how are they different? The management of the open abdomen in trauma and emergency general surgery: part 1-damage control. Systematic review and meta-analysis of the open abdomen and temporary abdominal closure techniques in non-trauma patients. Anatomical, physiological, and logistical indications for the open abdomen: a proposal for a new classifcation system. The open peritoneal cavity: etiology correlates with the likelihood of fascial closure. The open abdomen and temporary abdominal closure systems–historical evolution and systematic review. Temporary closure of the open abdomen: a systematic review on delayed primary fascial closure in patients with an open abdomen. Long-term vacuum-assisted closure in open abdomen due to secondary peritonitis: a retrospective evaluation of a selected group of patients. Multicentre prospective study of fascial clo- sure rate after open abdomen with vacuum and mesh-mediated fascial traction. Factors affecting primary fascial closure of the open abdomen in the nontrauma patient. Vacuum and mesh-mediated fascial trac- tion for primary closure of the open abdomen in critically ill surgical patients. Prospective evalua- tion of vacuum-assisted closure in abdominal compartment syndrome and severe abdominal sepsis. Deferred primary anastomosis versus diversion in patients with severe secondary peritonitis managed with staged laparotomies. Abdominal com- partment syndrome and intra-abdominal sepsis: two of the same kind? Supranormal trauma resuscitation causes more cases of abdominal compartment syndrome. Secondary abdominal compartment syndrome: an underappreciated manifestation of severe hemorrhagic shock. Is the evolving management of intra-abdominal hypertension and abdominal compartment syndrome improving survival?
Cotton patties safe roxithromycin 150 mg, soaked in either oxymetazoline or epinephrine order roxithromycin now, are placed between the middle turbinate and the septum for the purpose of hemo- stasis order roxithromycin online now. For the endoscopic approach, the nasal preparation is perhaps more important as even small amounts of bleeding can make the exposure difcult. Surgical Approaches The manner in which the surgeon accesses the sphenoid sinus can be broadly divided into endonasal and sublabial approaches. The magnifed drawing of the surgeons have advocated an endonasal direct sphenoidot- patient’s head displays the sublabial approach with the nasal specu- 20 omy. Operative Surgi- fewer anterior septal complications and a more rapid ac- cal Techniques: Indications, Methods, and Results, Vol 1, 4th ed. The traditional microscopic exposure involves identifed typically at the inferior third of the superior tur- only removal of the anterior wall of the sella turcica. The mucosa at the keel of the sphenoid bone adjacent and mallet or drill may be used to gain initial access to the to the ostium is then either incised with a Cottle elevator sellar dura followed by use of the Kerrison punch. The Cottle elevator sellar bone has been thinned by the tumor and can be eas- can then be used to refect the posterior wall of the nasal ily out-fractured. The goal of bony removal is to expose the septum and expose the contralateral sphenoid ostium. The dura just medial to the medial surface of the cavernous seg- bone beyond the two ostia can then be removed, which ment of the carotid artery bilaterally. A soft tissue shaver is berances most often cannot be completely visualized with then used to efciently remove the mucosa over the ante- the microscopic approach, this bony removal requires the rior wall of the sphenoid sinus. The shaver in combination combination of direct visualization and surgical feel with with backbiting instruments can then be used to produce a the Kerrison punch (Fig. Inferiorly the bone forming posterior septectomy, an essential component to the binasal the sellar foor should be removed and superiorly the bony approach. The surgeon can then use the endoscope to look opening should reach the inferior border of the superior into the contralateral nostril, lateralize the middle turbinate, intercavernous sinus. In this approach, the bony opening terior sphenoid wall should be elevated to expose the bony is extended beyond the anterior wall of the sella turcica to surface. If the from attempting to recapitulate a mononostril microscopic source of bleeding is not adequately appreciated and hemo- approach to a more practical binostril approach. There has stasis is not efectively achieved intraoperatively, bleeding also been a shift from using an endoscope holder to using from this artery can continue postoperatively and lead to a threehand technique. The anterior sphenoidot- using the latter approach is the pseudo–three-dimensional omy is then performed such that the opticocarotid recess is surgical view that can be generated by movement of the en- visualized superolaterally and the clivus is identifed inferi- doscope during the operation. The right nostril is typically the endoscopic sphenoidotomy must be larger that what is used for this purpose, unless a septal deviation signifcantly typically performed during a microscopic approach. The surgeon is using the 0-degree short endoscope for this portion of the approach. The opening of the sella using the endoscope does not dif- The surgeon is then able to use both hands for tumor resec- fer in dimension compared with the microscopic approach. The sphenoid However, because the intrasphenoidal anatomy is often bet- mucosa is frst removed only over the anterior wall of the ter visualized endoscopically, a more precise opening of the sella turcica. Most often the anatomy is seen well to remove the anterior wall of the sella turcica to the same enough to forgo an intraoperative x-ray. The assistant surgeon can use the 0-, 30-, or 45-degree long endoscopes for this portion of surgical procedure. In must take care not to injure mucosa when placing the blade these patients, frameless image guidance can be helpful. To obviate the risk of mucosal injury, the sur- geon may also use a knife with a retractable blade as de- signed by Paolo Cappabianca. The tumor is also resected Tumor Resection in the same sequential manner as in the microscopic tech- In the microscopic approach, the operative microscope nique, frst generating a plane between the dura and the should be adjusted prior to incising the dura such that the tumor. Subsequently, the tumor is removed inferiorly, later- objective distance is approximately 375 mm to allow for ally, and then superiorly. After tumor resection the 30- and adequate space for both the operative instruments and the 45-degree endoscopes can be used to better visualize the surgeon’s hands. In addition, the magnifcation should be set cavernous sinus wall and diaphragm sella. The dura ference in an endoscopic removal of a tumor is that the tu- is then typically opened with a surgical blade. This improves the A nerve hook is then used to generate a plane between the surgical efciency and provides a more certain removal of inner dural layer and the tumor/pituitary gland surface. The operative microscope can be adjusted to partially Closure visualize the medial wall of the cavernous sinus bilaterally. In the presence of a small hole in the be delivered into the surgical feld via either injection of diaphragm sellae, the sella is packed with an abdominal fat 10 mL of air or saline through a lumbar drain, by a Valsalva graft. The sella is then reconstructed with either the bony maneuver, or by jugular vein compression. How- autologous bone or cartilage is unavailable, a bioabsorbable 22 Microscopic versus Endoscopic Transsphenoidal Pituitary Surgery 233 plate must be used to reconstruct the anterior sellar wall. The primary ported the results of 219 female patients who underwent mi- diference is that after an endoscopic technique the defect is crosurgical resection of prolactinomas. Not only is the bony anterior sphenoidotomy larger patients treated between 1976 and 1979 and those treated in all directions, unlike the microscopic transseptal ap- between 1998 and 1992 to assess the role of surgery before proach, but also the nasal mucosa overlying the sphenoid (group 1) and during (group 2) the era of dopamine agonist is completely removed during the approach. Also because a speculum is not used, the adenomas and between 80 and 88% of patients with either fat graft can be more difcult to place during an endoscopic intrasellar or suprasellar macroadenomas displayed initial approach. The authors reported a 82% continued remission rate with a median follow-up I Microscopic Versus Endoscopic Surgical of 15. With regard to Cushing’s disease, Pouratian et al31 re- The microscopic transsphenoidal approach has been the most common technique for resecting pituitary lesions ported the outcomes in 111 patients with the diagnosis of over the past 40 years. Consequently, the majority of large Cushing’s disease without postoperative pathologic con- surgical series include patients with tumors primarily re- frmation. In addition, many of the older se- a drop in serum cortisol levels to 2 µg/mL or lower within ries do not diferentiate among those patients treated via 72 hours of surgery. The authors reported that 50% of the microscopic, endoscopic-assisted, or pure endoscopic patients achieved postoperative remission as compared approach. Over the past 10 years, larger case series have with 79% for the 490 total transsphenoidal operations been published reporting the surgical results using the pure for Cushing’s disease performed by this chapter’s senior endoscopic approach alone. Of the specimens, 161 contained tumor Microscopic Approach cell invasion and 192 displayed no evidence of invasion. In Laws and Jane21 reported their series of 4020 transsphe- addition, 291 specimens were from primary transsphenoidal noidal operations in which the majority of cases used the resection and 55 specimens were from repeat transsphenoi- microscope approach alone. The neuropathologist identifed dural invasion nonfunctioning adenomas and preoperative visual loss, 87% in 41% of the former group and in 69% in the latter group.
Renal concentrating function with prolonged sevoflurane or enflurane anesthesia in volunteers best roxithromycin 150 mg. Inorganic fluoride nephrotoxicity: Prolonged enflurane and halothane anesthesia in volunteers buy discount roxithromycin 150mg. Human kidney methoxyflurane and sevoflurane metabolism: intrarenal fluoride production as a possible mechanism of methoxyflurane nephrotoxicity purchase roxithromycin 150 mg without a prescription. Influence of volatile anesthetics on myocardial contractility in vivo: Desflurane versus isoflurane. Cerebral hemodynamic response to the introduction of desflurane: a comparison with sevoflurane. Context- sensitive half-time demonstrates the influence of the distributive process in governing drug disposition. Dexmedetomidine is unique as a sedative in that it has limited respiratory depressant effects. Pharmocokinetics: General Principles for Intravenous Anesthetics 1253 Traditionally, intravenous anesthetics have been utilized for the induction of anesthesia. Thiopental was introduced into clinical practice in 1934 and was the gold standard for intravenous anesthetics for 50 years. Thiopental had a rapid, smooth onset of sedative and hypnotic effects, predictable pharmacokinetics, and a rapid and smooth emergence. However, thiopental has a long context-sensitive half-time that made it less ideal for use as an infusion. A review article from 1989 stated that the use of intravenous anesthetics for maintenance was unpopular because bolus administration resulted in swings in hemodynamics and anesthetic level. The introductions1 of anesthetics with shorter durations (midazolam, propofol, remifentanil) and the development of variable rate infusion pumps allowed for routine use of intravenous anesthetics for maintenance. Combination of these modalities with a depth of anesthesia monitor has been utilized to create a closed-loop automated anesthesia delivery system. Table 19-1 Properties of the Ideal Intravenous Anesthetic Agent No single anesthetic agent is perfect. The characteristics of the ideal intravenous anesthetic agent were described by Hemmings and are outlined in Table 19-1. The ideal intravenous anesthetic would cause2 hypnosis and amnesia with a rapid onset (time of one arm–brain circulation), minimal cardiovascular and respiratory effects, and rapid metabolism. Propofol has become the new “gold standard” in anesthesia practice, with a rapid onset, rapid recovery after bolus administration from redistribution, and utility as a continuous infusion. Propofol is remarkable for how patients are 1254 awake and oriented after administration with lack of “hangover” effect that was associated with older anesthetics. It causes hypotension, respiratory depression, pain with injection, and has a prolonged duration with continuous infusion. The slight delay between target blood concentration and effect organ (brain) response is known as hysteresis. This delay occurs because of differences between peak plasma concentration and peak drug concentration in the brain. The action of a single bolus injection is terminated by redistribution of the anesthetic to lean tissues such as muscle. This property of intravenous anesthetics is key to understanding their pharmacokinetics in relation to continuous infusion and maintenance. An initial bolus or loading dose of an anesthetic establishes the desired blood concentration of the drug. Redistribution of intravenous anesthetics to nonactive tissues accounts for part of their initial clearance; however, this becomes less important as those tissues equilibrate with the blood. Therefore, the rate of infusion of an intravenous anesthetic for maintenance of anesthesia decreases over the duration of an infusion to maintain the desired blood concentration. An understanding of the pharmacokinetics of intravenous anesthetics is important to understanding their administration. Following a bolus of an intravenous drug, the plasma concentration over time resembles the curve in Figure 19-1. Essentially, there are three phases that occur after a bolus injection of propofol. The first phase is a rapid distribution phase;4 propofol rapidly distributes from the plasma to peripheral tissues. The second phase is a slow distribution phase; propofol continues to distribute to other tissues concurrent with return of drug to the plasma from the rapid distribution tissue. The last phase is the terminal phase, or elimination phase, where propofol is removed from the body. Decreases in blood concentration occur in three components corresponding to rapid distribution (A), slow distribution (B ), and elimination (C). The triexponential curve represents the algebraic sum of the individual exponential functions. Context-sensitive half time in multicompartment pharmacokinetic models for intravenous anesthetic drugs. The distribution of2 3 drug to the peripheral compartments and the elimination of propofol (G ) can1 be matched with an appropriate infusion rate (r(t)) that would then allow for maintaining a desired target blood concentration. However, over time, the propofol will begin to accumulate in the peripheral compartments. Less propofol is removed from the central circulation by redistribution to these peripheral compartments. With prolonged time, the contributions of propofol from the peripheral compartments become greater, thus requiring less drug to be infused to maintain target blood concentration. This also leads to a longer time to awakening, and to the concept of context-sensitive half-time. It is the time it takes for the plasma concentration of a drug to decrease to 50% of its original concentration. This concept works well to describe a one- compartment model for a drug distributed only to the blood, or if the drug is administered only once. In contrast, pharmacokinetic modeling that describes intravenous anesthetics administered by infusion needs to account for multiple compartments, phases of distribution and elimination. Context-sensitive half-time is defined as the time to achieve a 50% reduction in concentration after stopping a continuous infusion. Context- sensitive half-time demonstrates the influence of the distributive process in governing drug disposition. This refers to both the transfer of drug out of the plasma into peripheral compartments and the reverse process when there is a net transfer of drug back to the central compartment. In comparison to thiopental, propofol has a much lower context-sensitive half-time.
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