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Antemortem blisters also typically have a red discolored order discount phenazopyridine online gastritis y dolor de espalda, and shrunken appearance cheap phenazopyridine line gastritis diet �������. Tis concept remains Burns following exposure to heat are thermal burns order 200mg phenazopyridine gastritis diet 2000, controversial in some jurisdictions. Also, a dead body which may occur following contact with hot liquid or from a house fre, which is exposed to intense heat, will fre. Children may be scalded while lef unattended in a decompose at a much slower rate than a dead body not bathtub. Radiant heat in a dry environment cise great care in evaluating these cases as they may be a will cause tissue to become frm due to dehydration and result of abuse or neglect. A child with both feet scalded coagulation of the sof tissues; hair is ofen still pres- with scarring around a shoe pattern is more likely the ent but may be discolored by smoke. A child who is waiting to take advances depends on the amount of heat and humid- a bath will not usually have shoes on and will most likely ity and the duration of exposure. Te burns will be on produce postmortem artifacts that may be misinter- one foot but not usually both. Both feet scalded at once preted as antemortem injury, such as an epidural hem- may indicate dunking into hot water as punishment. Epidural hemorrhage may be postmortem and If an individual dies and is placed in a tub full of hot is caused by heat-related contracture of the dura mater, water afer death, the body will develop thermal injury forcing blood from adjacent vessels into the epidural more readily than if a living body was placed in the space. A dead body lef in warm water will ties from house fres are caused by smoke inhalation. Fire fatalities that occur generally defned as being less than 1000 volts for alter- outside in an open space ofen do not have signifcant nating current and less than 1500 volts for direct current. T e degree of injury depends heated gases damage the upper airways, including the on many factors, including the duration of exposure and laryngeal mucosa, causing death from refexive clo- the amount of heat generated. Lightning bolts occur with an enor- smoke inhalation are ofen refected by the amount of mous short-term release of electricity, ofen producing carbon monoxide present in the blood. Patterns simi- poisonous substances in smoke associated with house lar to this may be observed in high-voltage electrocu- fres that may not be routinely tested for in toxicological tion. Te mechanism of death is Tere are ofen other signifcant poisons associated usually arrhythmia and more likely to occur if the cur- with burning materials that can rapidly contribute to rent passes directly through the heart. A fre victim does not occur due to asphyxia if there is interference with the need a lethal level of carbon monoxide to die of smoke central nervous system’s respiratory centers or paralysis inhalation. Carbon monoxide is one needs an entrance and exit point for electricity to a colorless, odorless gas that reversibly binds the hemo- pass through the body. An otherwise healthy individual globin molecule approximately 200 times greater than may be found lying barefoot and on a damp foor next oxygen, resulting in hypoxia and possible death. Tis is why of carbon monoxide that exceed 50% saturation are adequate scene investigation is crucial. It is also impor- considered life-threatening, but may cause death with tant to keep the electrical device as evidence to be tested, levels less than 26% saturation. Tese burns most ofen involve injury to the Someone with marked coronary-artery atherosclerosis skin or mucosa, leaving red discoloration or slough- would ofen require much less carbon monoxide expo- ing of the superfcial layers. More extensive injuries sure to produce death than a young healthy individual may involve damage to the underlying tissue, including with slight atherosclerosis. Carbon monoxide levels caustic substance, which include acids, bases, and other of 15%–30% are associated with dizziness, nausea, and chemicals that can damage the body. Cherry-red lividity frst becomes apparent at die acutely following chemical burns from many dif- levels of 30%–35%. Te half-life for carboxyhemoglobin ferent mechanisms including hemorrhage, infection, elimination in a resting adult at sea level is generally or dehydration, or they may die many years following 4–5 hours. For instance, if an individual attempts to ing administration of pure oxygen, and may be further commit suicide by ingesting lye 20 years earlier and later reduced to 24 minutes by using oxygen at 3 atmospheres develops esophageal cancer as a result of these burns, of pressure. Also, if there accidently drink caustic substances, leading to gastroin- is more than one fatality without obvious cause, one testinal perforation that may lead to adhesion and gas- should consider carbon monoxide poisoning. In this case, Electrical burns may be due to low- or high-voltage the manner of death would be accidental. Te electrical current may be direct or alter- very important to fnd out the initial event that starts nating in nature. Alternating current is more likely to the ball rolling in the sequence of events that eventually cause a fatal cardiac arrhythmia than direct current. High voltage is generally defned as greater than 1000 Radiation is defned as energy distributed as waves volts for alternating current and greater than 1500 volts or particles across the electromagnetic spectrum. High-voltage burns are usually asso- includes electric, radio, radar, microwaves, infrared, vis- ciated with extensive obvious injury. Low voltage is ible light (lasers), ultraviolet light, x-rays, gamma rays, Burns 453 and cosmic radiation. Waves are characterized as hav- cataracts, burns to the retina and skin, necrosis, fbro- ing long wavelengths and low frequencies, whereas par- sis, and cancer. Generally speaking, proliferating cells ticles have short wavelengths and high frequencies. Te are afected more substantially with acute exposure as types of biological efects vary greatly depending on the indicated by damage to the gastrointestinal and hema- type of radiation, duration of exposure, and interme- topoietic systems with increased risks of infection, nau- diate barriers. Second- degree burns are often more painful than third-degree burns due to less destruction of nerve endings. There is debate in the literature about distinguishing antemortem from postmortem burns. Many believe blister forma- tion in a nongravity-dependent area with a red border indicates vital reaction and antemortem occurrence. First-degree thermal burns in this picture are characterized by the red discoloration without blister formation or skin slippage. Note the areas of collapsed blister formation, which are consistent with a postmortem burn. Sometimes it is difficult to interpret antemortem burns if continued heat causes fuid-flled blisters to collapse and fuid to evaporate. Full thickness refers to involvement of the epidermis, dermis, and subcutaneous layers. These are often less painful than second-degree burns due to more damage of nerve endings. She had the heater turned up to full, the gas tank was empty, and she had not been seen for several days. Her body showed signifcant mummifcation with putrefaction and radiant heat damage. Note these postmortem anemic lacerations in the popliteal regions created when the body was moved to the autopsy table. Drying of skin is associated with decreased elasticity with greater tendency to lacerate instead of stretch.

Experimental data suggest the cool-tip saline spray catheter may produce less char and thrombus than the internally cooled catheter generic phenazopyridine 200mg overnight delivery gastritis symptoms from alcohol. The latter two methods necessarily result in introducing a variable amount of saline into the circulation blood volume depending on the number of and time over which the lesions are given order phenazopyridine 200 mg mastercard treating gastritis without drugs. Several companies manufacture ablation catheters that provide external irrigation proven 200 mg phenazopyridine gastritis diet 90x. The Thermocool (Biosense Webster) catheter (A), was the first catheter approved for the ablation of atrial fibrillation; it uses six irrigation ports at the tip of the catheter. Jude Medical) provides real-time contact force and vector measurements based on light interferometry. The SmartTouch catheter (Biosense Webster) utilizes a precision spring in the catheter tip; spring displacement proportional to tip contact force/vector. Recently the limitation of contact has been addressed by real-time measurement of contact force (Fig. Clinical trials of force sensing catheters for ablation of atrial fibrillation showed that unblinded access to real-time data produced meaningful improvements in freedom from atrial fibrillation in short-term follow-up. In the past decade, there has been interest in using lasers intraoperatively for the management of ventricular arrhythmias or the creation of A-V block. Depending on the laser used, the distribution of light within the tissue and the degree and site of destruction are quite variable and highly dependent on the wavelength. With the argon laser, the light energy is absorbed rapidly in the first few millimeters of tissue, resulting in surface vaporization with crater formation. While the pathologic responses were similar qualitatively, the laser lesions were associated with less ventricular arrhythmias. The advantages of laser-delivered energy are that it takes a short period of time to deliver and the amount of energy delivered can be easily controlled. However, if catheter delivery systems are to be developed, contact issues with the endocardium, the site in the heart at which ablation is to take place (e. A laser balloon delivery system (Cardiofocus) which could allow tissue visualization (to ensure contact) is currently under investigation (Fig. Cryoablation Cryoablation has been used in the surgical treatment of a variety of arrhythmias for over 30 years. While near transmural lesions can be produced intraoperatively using temperatures of −60°C in the presence of cold cardioplegia, achievement of such lesions with a catheter-based delivery system has not been definitively established at this time. However, several companies have developed catheter-based cryodelivery systems, which improved energy delivery based on phase change (liquid nitrogen to gas) within the catheter tip. Catheter- based delivery systems are used for ablation of A-V nodal tachycardia and paraseptal bypass tracts, particularly in children. This design obviates some of the difficulty with local blood flow as the balloon structure occludes the pulmonary vein being ablated. Ultrasound can be focused, and therefore has the unique property of not requiring tissue contact. Preliminary studies have applied ultrasound to the ablation of focal triggers by isolating the pulmonary vein from the atrial myocardium using ultrasound delivered via a balloon placed in a pulmonary vein. A second-generation forward firing device which delivered high- intensity focused ultrasound (Prorhythm) was removed from clinical use because of a high incidence of procedural complications, particularly atrioesophageal fistula. Control of Supraventricular Arrhythmias by Ablative Techniques The development of surgical techniques to cure arrhythmias began with the first successful electrophysiologically directed cure of the Wolff–Parkinson–White syndrome. Will Sealy successfully divided an A-V bypass tract localized to the right lateral A-V groove by epicardial mapping. In fact, the widespread use of catheter ablation techniques has virtually eliminated the need for surgery to manage drug-resistant supraventricular tachycardias that are due to the Wolff–Parkinson–White syndrome and A-V nodal reentry, and A-V junctional ablation, which represents of course an indirect treatment of atrial fibrillation in terms of control of the ventricular response. The major role of surgery today is for the “cure” of atrial fibrillation as a primary procedure or as an adjunct to valvular surgery (see below). Ablation of Atrioventricular Bypass Tracts and Variants of Pre-excitation Successful ablation of atrioventricular bypass tracts requires precise localization of the atrial and/or ventricular insertion site of the bypass tract. As noted in Chapter 10, A-V bypass tracts may occur anywhere around the tricuspid and mitral annulae except for the region of aortomitral continuity, at which no ventricular myocardium lies below the atrium. The tricuspid annulus has a greater circumference (approximately 12 cm) than the mitral annulus (approximately 10 cm) and is not a complete fibrous ring, but may have many regions of discontinuity. Moreover, there is a folding over the atrium and ventricle, as shown in Figure 13-7, such that it may be difficult to position the catheter at the tricuspid annulus because of a tendency of the catheter to fall into the folded over “sac. An annular ablation at a site that is nearly at the annulus may fail because the atrial insertion site may be as far as 1 cm away from the annulus in the folded-over atrial sac. This folded-over atrium and bizarre angle required for mapping of the inferior and posterolateral aspects of the right atrium may make mapping of this region difficult using an inferior cava approach. Thus, in some cases a superior vena cava approach may be required to allow full exploration of the “folded-over atrial sac” and the inferior, inferoanterior (formerly referred to as inferolateral) and lateral positions around the tricuspid annulus. The standard inferior vena cava approach, however, is quite adequate to map the superior aspects of the tricuspid ring. This may be useful in patients with Ebstein anomaly in which the triscupid valve is displaced into the ventricle or in patients who have had multiple unsuccessful attempts at ablation of right-sided pathways. I do not believe a right coronary catheterization should be used routinely, and in fact should be discouraged, since it has potential disastrous consequences. There has been no long-term follow-up of coronary arteries in patients in whom this procedure has been performed, and there should be serious concern regarding endothelial abrasion by such a catheter, resulting in initiation of an atherogenic process. In my opinion, careful and detailed mapping with standard ablation catheters is adequate. A guiding sheath is particularly useful when an inferior vena cava approach to an inferoanterior bypass tract is utilized. Use of a halo catheter or a multipolar catheter positioned around the tricuspid annulus can provide very good regional localization capabilities to guide the roving ablation catheter (Fig. These multipolar catheters are used in an analogous fashion to coronary sinus catheterization for left- sided pathways (see below). A: The right atrioventricular (A-V) ring is schematically shown with a blow-up of the annular region. The ring is incomplete and the atrium “folds” over the ventricle producing a sack. B: The left A-V ring is solid, and the relationship of the coronary sinus, coronary artery, and potential bypass tracts are shown. The anatomy of both A-V rings differs and has led to different ablation approaches for right- and left-sided bypass tracts. As is the case in this recording, it is often difficult to position the Halo catheter at the tricuspid annulus (as demonstrated by the large atrial and absent ventricular signals). Nonetheless, this technique allows for rapid regionalization (earliest atrial recording on Halo 10), and a point of reference in terms of location and timing for the mapping catheter, which has an annular signal with much earlier atrial activation.

Fascial and muscular abnormalities in women with urethral hypermobility and anterior vaginal wall prolapse discount phenazopyridine 200mg free shipping gastritis cancer. Periurethral and paravaginal anatomy: An endovaginal magnetic resonance imaging study order phenazopyridine canada gastritis diet ��. Advanced anterior vaginal wall prolapse is highly correlated with apical prolapse order genuine phenazopyridine gastritis diet 1200. A 3D finite element model of anterior vaginal wall support to evaluate mechanisms underlying cystocele formation. Accuracy of clinical assessment of paravaginal defects in women with anterior vaginal wall prolapse. Clinical evaluation of anterior vaginal wall support defect: Interexaminer and intraexaminer reliability. Prevalence of hydronephrosis in women undergoing surgery for pelvic organ prolapse. The mechanism of urinary continence in women with severe uterovaginal prolapse: Results of barrier studies. Prolapse surgery with or without stress incontinence surgery for pelvic organ prolapse: A systematic review and meta-analysis of randomised trials. A model for predicting the risk of de novo stress urinary incontinence in women undergoing pelvic organ prolapse surgery. Protective effect of suburethral slings on postoperative cystocele recurrence after reconstructive pelvic operation. The incidence of ureteral obstruction and the value of intraoperative cystoscopy during vaginal surgery for pelvic organ prolapse. Reanalysis of a randomized trial of 3 techniques of anterior colporrhaphy using clinically relevant definitions of success. Reoperation for pelvic organ prolapse within 10 years of primary surgery for prolapse. Anatomic and functional outcome of vaginal paravaginal repair in the correction of anterior vaginal prolapse. Prospective randomized trial of polyglactin 910 mesh to prevent recurrence of cystoceles and rectoceles. Early experience with mesh excision for adverse outcomes after transvaginal mesh placement using prolapse kits. Single-incision vaginal approach to treat cystocele and vault prolapse with an anterior wall mesh anchored apically to the sacrospinous ligament. Minimal mesh repair for apical and anterior prolapse: Initial anatomical and subjective outcomes. Utero-vaginal suspension using a bilateral vaginal anterior sacrospinous fixation with mesh. The use of intraoperative cystoscopy in major vaginal and urogynecologic surgeries. Incidence and management of graft erosion, wound granulation, and dyspareunia following vaginal prolapse repair with graft materials: A systematic review. Complications of transvaginal monofilament polypropylene mesh in pelvic organ prolapse repair. Evaluation and management of complications from synthetic mesh after pelvic reconstructive surgery: A multicenter study. Sexual activity and vaginal topography in women with symptomatic pelvic floor disorders. In general, hernia occurs when a rupture in the smooth muscle or connective tissue allows a bodily structure to protrude. An enterocele is usually referred to as a herniation through or into the vagina typically as a posterior enterocele, which develops in the rectovaginal space (pouch of Douglas or cul-de-sac). The anterior enterocele in the vesicovaginal space is a rare entity [1], which might occur after cystectomy or after hysterectomy [2]. An enterocele is a form of pelvic organ prolapse with the bowel protruding into the vagina. Why and how are etiological and pathophysiological issues which are illustrated in this chapter. Surgical treatment of an enterocele is often concurrent or identical to operations for vaginal vault prolapse. Therefore, the pouch of Douglas is an anatomical structure that plays an important and probably predisposing part. The pouch of Douglas is normally closed and does not contain intestine or omentum. In anatomy textbooks, the extent of the pouch of Douglas has traditionally been described as 2–3 cm below the uterosacral ligaments (e. Histological studies by Uhlenhuth and colleagues have demonstrated that in the fetus the pouch of Douglas may extend to the perineal body [3]. The consecutive fusion of the anterior and posterior peritoneum forms the rectovaginal septum and determines the depth of the pouch of Douglas [3–5]. According to Uhlenhuth, the rectovaginal septum is distinguishable from the “fascial” capsule of the vagina and rectum. In contrast to anatomy textbooks, intra-abdominal measurements of the depth of the pouch of Douglas in young nulliparous women revealed great variations with 25%–75% of the posterior vaginal wall covered with peritoneum [6]. The mean depth of the pouch of Douglas was 49% of vaginal length in nulliparas, 46% in parous women, and was significantly deeper (72%) in patients with posterior vaginal wall prolapse. It would appear that the deep pouch of Douglas is frequently present in young nulliparous women without pelvic organ prolapse, which implies a congenital variation and predisposition [6]. A sophisticated concept of normal pelvic organ support accentuates the imperative role of several factors including integrity of the anterior and posterior endopelvic fascia with intact attachments as well as normal tone, position, and functionality of the levator ani muscle. Normal pelvic floor muscle and fascial structures are required to hold the perineum in place and ensure normal bladder, bowel, and sexual function. It is apparent that fascial defects in the three levels of vaginal support and the posterior compartment may contribute to pelvic organ prolapse including enteroceles [7,8]: the normal pelvic floor tone is essential for the nearly horizontal axis of the vagina, which in turn is necessary to allow for a normal pelvic floor protecting intra-abdominal pressure distribution. Intra-abdominal measurements of the depth of the pouch of Douglas have shown that in women with posterior vaginal 1268 wall and anterior rectal wall prolapse the pouch of Douglas is significantly deeper and may reach the level of the perineal body [6]. In addition, the anatomy of the pouch of Douglas is considerably different, which is a recognized feature in some studies. In women with severe pelvic organ prolapse, a large or voluminous rectovaginal pouch was a consistent anatomic finding, requiring obliteration during pelvic reconstructive surgery [9–11]. Apart from a mobile vaginal axis and a dehiscence of the levator hiatus, French authors reported a “grande fosse pelvi-périnéale”—a large pelvic pouch—to be the principal lesion in women with enteroceles [12]. Other authors described this phenomenon as an abnormally deep and wide cul-de-sac with a 3D enlargement [13]. Their anatomical observations included a deep and wide rectovaginal pouch and a rectosigmoid colon, which closely follows the sacral curve (Figure 83.

When serum creatinine levels are “high normal” in the geriatric patient discount phenazopyridine 200mg fast delivery gastritis burning stomach, it may be demonstrating renal insufficiency or more significant impairment cheap 200 mg phenazopyridine free shipping gastritis and duodenitis definition. The combination of reduced renal blood flow and decreased nephron mass increases the risk of elderly patients for acute renal failure in the postoperative period discount phenazopyridine 200 mg otc diet chart for gastritis patient. Other physiologic renal changes predispose elderly patients to develop dehydration or fluid overload because of the inability to handle sodium loads, concentrate, or dilute (offload volume) when conditions are right. This is exacer- bated further by reduction in response to antidiuretic hormone and aldosterone. Perioperative issues: Excretion of drugs is greatly affected in elderly patients, and care must be given to administration and dosing. Fluid management is more difficult and may lead to acute electrolyte disturbances (hypokalemia and hyper- kalemia). Preoperative outpatient use of diuretics further complicates intraoperative fluid and electrolyte management. Additionally, neurons decrease in size and lose complexity of their dendritic tree. Physiologic changes: The synthesis of some neurotransmitters and the number of their receptors are reduced. Aging is associated with an increasing threshold for nearly all sensory modalities, including touch, temperature sensation, proprioception, hearing, and vision. Cerebral blood flow also decreases about 10% to 20% in pro- portion to neuronal losses. Administration of a given volume of epidural anesthetic results in more extensive cephalad spread with a shorter duration of analgesia and motor block. About 30% of geriatric patients demonstrate s/sxs of these syndromes after surgery, including 10% to 15% of patients older than 60 years of age demonstrating cognitive dysfunction up to 3 months after major surgery. She has a history of atrial fibrillation and has been treated with warfarin for 3 years. The patient states she has been on a couple of medications for her blood pressure, but she forgets to take them intermittently. The patient verifies that she is a current smoker and uses inhalers at least once a day. Despite multiple medical issues, the patient states she does a lot of her own lawn work and walks on her farm, where she fell and was injured. This patient has medical issues that need to be dealt with before surgery, but it is reasonable to expect that surgery could occur in the next few hours upon further evaluation. Optimal anesthetic management of geriatric patients depends on an understanding of the normal changes in physiology, anatomy, and response to pharmacologic agents that accompany aging, which is similarly seen in pediatric patients. Decreased ability to increase heart rate in response to hypovolemia, hypotension, or hypoxia Decreased lung compliance Decreased arterial oxygen tension Impaired ability to cough Decreased renal tubular function Increased susceptibility to hypothermia Although there are similarities among patients at the extremes of the age continuum, geriatric patients demon- strate an even wider range of physiologic variation with increasing age then pediatric patients. Geriatric patients usually present with an impressive list of outpatient medications; Review them! These should generally be administered to patients perioperatively if they are on such medications chronically to avoid the effects of β-blocker withdrawal. The use of regional techniques is becoming increasingly popular in the outpatient setting, and the use of ultrasound and nerve stimulation has improved regional block success rates. The surgeon and anesthesia provider must identify patients in whom an ambulatory or office-based setting is likely to provide benefits (ease for patients, reduced costs) that outweigh risks (the lack of immediate availability of all of the services a hospital provides). Patient Considerations for Ambulatory Anesthesia Each patient must be considered in the context of comorbidities, the type of surgery to be performed, and expected response to anesthesia. Other factors considered when selecting patients for ambulatory procedures include airway management problems, sleep apnea, morbid obesity, previous adverse anesthesia outcomes, allergies, and the patient’s social network. Procedures suitable for ambulatory surgery should have a minimal risk of perioperative hemorrhage, airway com- promise, and no requirement for specialized postoperative care. Cardiac conditions: Increasingly, patients present to ambulatory surgery with a variety of cardiac conditions treated both pharmacologically as well as mechanically. Patients should remain on β-blockers perioperatively; antiplatelet agents should not be discontinued unless a discussion has occurred between the patient, cardiologist, and surgeon regarding both the neces- sity of surgery and the necessity of discontinuing antiplatelet therapy. Difficult airway: Patients with known or likely difficult airways are most likely not candidates for office-based procedures; however, they may be appropriately cared for in an ambulatory center provided there is availability of difficult airway equipment, additional experienced anesthesia providers, and surgeons or anesthesiologists capable of performing emergency tracheostomy and cricothyroidotomy. Have discharge instructions and prescriptions from surgeon and anesthesiologist 9. Such policies should be focused on ensuring that the “sedationist” has the necessary skills to provide for patient rescue if mild or moderate sedation becomes deep sedation or anesthesia. Sedation providers should know how to reverse benzodiazepines and opioids and how to provide bag/mask airway support and should be facile in the use of airway adjuvants. Postoperative epidural analgesia may significantly reduce the time until extubation and reduce the need for mechanical ventilation after major abdominal and thoracic surgery. Regional anesthesia’s attenuation of the inflammatory response may also preserve immunity perioperatively, thereby reducing the risk of cancer spread. At the midline between spinous processes, layers from skin to epidural space include skin, subcutaneous fascia, supraspinous ligament, intraspinous ligament, ligamentum flavum, epidural space, and dura. The spinal cord: Extends from the foramen magnum to L1 in adults (L3 in children). Encased by fatty tissue, a venous plexus, and three-layered meninges (pia, arachnoid, and dura). Spinal Nerve Roots At the cervical level, spinal nerves arise from the cord at the level above their respective vertebrae; however, starting at C8, they exit at the level below (there are eight cervical nerve roots but only seven cervical vertebrae). Lower nerve roots course some distance before exiting the intervertebral foramina because the spinal cord typically ends at L1; this collection of lower never roots is also known as the cauda equina. A dural sheath invests most nerve roots for a small distance upon exiting the spinal canal; therefore, blocks close to the intervertebral foramen (e. Spinal: Small dose and volume Epidural: Larger doses and volumes to achieve the same local anesthetic concentration Smaller, myelinated fibers are generally more easily blocked than larger, unmyelinated fibers; spinal nerve roots carry varying mixtures of both. Differential blockade: Phenomenon resulting from variability of fibers and decreasing concentration of local anesthetic with increasing distance from level of injection; results in sympathetic blockade that may be two segments higher than the sensory block, which in turn is usually two segments higher than the motor block. Somatic Blockade Blockade of posterior nerve root fibers interrupts somatic and visceral sensation, transmission of painful stimuli. Blockade of anterior nerve root fibers prevents efferent motor outflow, thereby producing skeletal muscle relaxation. Autonomic Blockade Blockade of anterior nerve root fibers also prevents autonomic outflow. Parasympathetic outflow is craniosacral; preganglionic parasympathetic nerve fibers exit the spinal cord with cranial and sacral nerves. Neuraxial blockade, therefore, results in decreased sympathetic tone and unopposed parasympathetic tone. High sympathectomy may not only prevent this compensatory vasoconstriction but may also block the car- diac accelerator fibers that arise from T1 to T4. Overall result = Hypotension + Bradycardia + Decreased cardiac contractility Anticipation and Treatment of Hypotension Volume loading a healthy patient with 10 to 20 mL/kg may help attenuate venous pooling. Left uterine displacement in the third trimester of pregnancy may help minimize obstruction to venous return. If hypotension occurs, administer a fluid bolus and place the patient in head-down position (autotransfusion).