By R. Gembak. Pfeiffer University. 2019.
The authors have also postulated that building this strong relationship may explain the observation of high patient satisfaction toward surgeons after palliative operation—even if there is no demonstrable benefit  cheap strattera 25mg otc. The palliative triangle facilitates interactions between patients buy genuine strattera online, families cheap strattera, and surgeons order generic strattera pills, and helps guide patients to the best decisions regarding palliative surgery. While this list is not comprehensive, it does offer a framework for approaching any palliative surgery situation. When surgery is not an option, it is important to know how to palliate common symptoms in patients with advanced illness (see Chapter 35). Bowel obstructions can occur at any level of the gastrointestinal tract from the stomach to the rectum. Depending upon the etiology (adhesions, cancer, stricture), the management can vary from nonoperative nasogastric decompression and bowel rest to bowel resection and/or intestinal diversion. Regardless of the etiology, initial management of a patient with a bowel obstruction should include appropriate intravenous fluid resuscitation based upon the degree of dehydration and the site of the obstruction and correction of any metabolic abnormalities. The bowel should be decompressed with a nasogastric tube if the patient is vomiting, and the patient should not be allowed to eat or drink to decrease gastrointestinal stimulation and secretions. Imaging studies, such as an abdominal series and/or a computed tomography scan of the abdomen and pelvis, are helpful to determine the level and nature of the obstruction. They can also demonstrate the presence of extraluminal air suggesting a perforation, and the presence or absence of ascites. Patients who are hemodynamically stable, who do not have peritonitis and have a normal or only mildly elevated white blood count (especially in the setting of dehydration), can initially be monitored closely (with the measures mentioned above) and given a chance for the obstruction to resolve without surgery. Signs and symptoms of peritonitis or an imaging study suggesting a “closed loop” obstruction (a loop of intestine twisted around its mesentery) are indications for a more urgent surgical intervention. Often the exact nature of that intervention cannot be determined until the time of surgery—adding an additional element of cognitive and emotional uncertainty that must be borne by the patient, family, and surgeon. Surgery may include resecting the section of obstructed intestine if it appears to be an isolated site, performing an intestinal bypass if the site cannot be resected, performing a diverting ostomy (either small or large bowel depending on the location of the obstruction), or placing a decompression gastrostomy tube for venting the stomach if the obstruction cannot otherwise be relieved. In the setting of a malignancy, these operations can be challenging, both technically as well as with regard to the decision-making, and they pose a high risk for perioperative morbidity and mortality . If the obstruction is located in the rectum or rectosigmoid colon or duodenum, it is reasonable to consider an endoscopic stent placement rather than surgery as the initial intervention. While the presence of carcinomatosis has been shown to increase the risk of failure of endoscopic stent placement for colonic obstruction, there is a 77% to 85% success rate [14–17]. For patients with a limited prognosis, an opportunity to avoid an operation that could involve either an intestinal diversion and ostomy or venting gastrostomy tube is an important consideration. For patients in whom it is felt that surgical or endoscopic relief of the bowel obstruction is not feasible, it is reasonable to evaluate them for a percutaneous endoscopic gastrostomy tube placement for gastric drainage. Surgical decision-making becomes more challenging for end of life patients who are not stable and require a decision regarding an emergent operation. It may be argued that this is not a purely palliative surgery consult as the surgical intervention has the potential to rescue the patient from a life-threatening complication of their life-limiting illness. On the other hand, it may also be considered palliative as it will not cure the patient of the underlying disease process. Needless to say, this is often an emotionally charged time, even for patients with long-standing illness such as advanced cancer, because they are now faced with the imminent risk of dying. Of the 376 patients who underwent emergency surgery for obstruction, the 30-day mortality rate was 18% with a 41% morbidity rate and 60% were discharged to an institution. While most patients will survive the initial operation, a substantial number will die soon after the surgery and many experience postoperative complications, reoperations, stays in nursing homes, or hospital readmissions. While these data are helpful for surgeons and caregivers to advise patients of the risks of surgery, set expectations for the postoperative experience, discharge location and overall survival, both at the time when the decisions is made for surgery and if complications occur, important data regarding whether the goals of the patients and families were met and whether or not they would make the same choice again are still severely lacking at this time. As with a lower intestinal obstruction, acute symptoms should be initially managed with nasogastric decompression, bowel rest, and intravenous resuscitation, including aggressive electrolyte repletion. Options for managing upper gastrointestinal obstructions include intraluminal stenting, surgical bypass, and decompression gastrostomy with possible feeding jejunostomy. Similar to colonic stenting, the potential benefits of duodenal stenting include immediate palliation of nausea and vomiting with a less invasive procedure than surgical bypass and earlier return to oral nutrition [20,21]. Stenting has been shown to provide a comparable survival outcome and equivalent morbidity and mortality to surgical bypass . In a systematic review of the literature from 1990 to 2008 comparing endoscopic stenting with open surgical bypass, Ly et al. The major limiting factor for the endoscopic approach is being unable to pass the scope through the obstruction. The major complications reported are gastric ulceration, bowel perforation, biliary obstruction, stent dysfunction, and stent migration. Stent placement would be contraindicated in patients with multiple levels of intestinal obstruction and should be considered carefully for patients with peritoneal carcinomatosis who are at risk of more distal obstructions. For patients in whom stenting is not an option, surgical bypass can relieve both the symptoms of the obstruction and allow the patient to resume enteral nutrition. Surgical bypass, most commonly in the form of a gastrojejunostomy, can either be performed laparoscopically or through a relatively small upper midline incision. The estimated risk of morbidity and mortality from these procedures is 25% to 60% and 0% to 25%, respectively [22,23]. While surgical bypass is usually technically successful, patient selection with regard to preoperative nutritional status and life expectancy is imperative to the palliative success of this approach. For example, in addition to general surgical risks such as bleeding or infection, a patient with chronic gastric outlet or duodenal obstruction who is malnourished is at increased risk of a leak from the intestinal anastomosis. Other potential complications specific to gastric bypass include dumping syndrome, alkaline reflux gastritis, and delayed gastric emptying. Placement of a gastrostomy tube for decompression is another option for palliation of gastric outlet, duodenal and nonoperable small bowel obstruction or profound gastrointestinal dysmotility from carcinomatosis. Gastrostomy tubes can be placed either endoscopically, fluoroscopically, or surgically (either laparoscopic or open). Decompression gastrostomy tubes provide patients the ability to drain the stomach as for nausea and to avoid vomiting. Many endoscopists, surgeons, and interventional radiologists are leery of placing gastrostomy tubes in the setting of malignant ascites. They are concerned about the risk of infecting the ascites, intraperitoneal leakage from the stomach due to poor apposition to the anterior abdominal wall, as well as leakage of ascites from around the tube. There is a growing body of literature demonstrating the safety of placing gastrostomy tubes in patients with malignant ascites from a variety of tumors [24–26]. Also, consideration of placing a peritoneal drainage catheter at the time of gastrostomy may also help lower any risk associated with the ascites. As gastrostomy may be the only viable palliative option for these patients, all efforts to manage the ascites and increase the safety of gastrostomy placement are warranted. Unfortunately, while the symptom relief from a paracentesis or thoracentesis is immediately helpful, it is usually temporary. For patients requiring frequent drainage of either the peritoneal or pleural cavity, a tunneled intraperitoneal catheter that can be intermittently connected to a self-contained vacuum drainage system is a helpful option . As there is often no cytoreductive surgery involved, this can be done laparoscopically, which, although less invasive, still does require general anesthesia. Similarly, an alternative treatment option for patients with recurrent malignant pleural effusion is pleurodesis. Pleurodesis can be performed using a number of different agents including talc, chemotherapy, or abrasion. The intent is to create an inflammatory reaction within the pleural cavity resulting in fusion of the visceral and parietal pleura, thereby obliterating the peritoneal space and the opportunity for fluid re- accumulation. Talc has been shown to be the most effective pleurodesis agent in randomized clinical trials with reported success rates of 60% to 90% . However, although these procedures can be done at the bedside, they do require the placement of a larger bore chest tube and can be rather painful . Unlike patients with a bowel obstruction, patients with a perforated viscus are more likely to have pain from peritonitis, adding another element of consideration to both the decision-making process and the emotional charge of the situation. Currently, there is a small, but growing body of literature supporting the use of nonsurgical management for bowel perforation in select (hemodynamically stable, non-peritonitic) patients. Some studies have reported a greater than 90% success rate in nonsurgical management of patients with perforated diverticulitis . Unfortunately, for patients with advanced cancer, who are not stable or who have peritonitis, and who undergo emergent surgery, the outcomes are even worse than for those with a bowel obstruction.
Therefore buy 10 mg strattera with amex, when anxiety is present and no clear psychological or medical cause is obvious buy generic strattera 40mg, a thorough search for an organic cause is indicated buy 10 mg strattera overnight delivery. Two syndromes that are particularly difficult to distinguish from primary anxiety are delirium and substance withdrawal buy cheap strattera 25 mg on line. In delirium, performance of tasks of attention, orientation, memory, and language is often impaired; rarely does an anxious patient have these deficits. By definition, delirium always has a medical cause; therefore, determination of its cause, rather than simply treating its symptoms, is vital. This diagnosis can be missed because patients either underreport their substance use or are unable to communicate. Patients can also withdraw from sedatives and opioids prescribed during a lengthy period of mechanical ventilation. A developing literature supports consideration of psychosocial factors as well, most frequently, anxiety, depression, and personality traits . Most generally, it activates the sympathetic nervous system, which directly causes vasoconstriction, tachycardia, increased blood pressure, platelet activation, and potential for arrhythmia [12,13]. Overall, these physiological changes may explain why anxiety—especially phobic anxiety—has been directly linked to an increased risk for sudden death . Further trials are required to determine whether the effect of anxiety is “dose”-dependent and whether effective anxiety treatment improves cardiac outcomes. Their use leads to a reduction of circulating catecholamines and may also cause coronary vasodilatation, prevent dysrhythmias, and retard platelet aggregation . Some [5,6,26], but not all [27,28], prospective trials demonstrate that high levels of anxiety predict cardiac events (e. Definitive study of the association between anxiety and cardiac events remains difficult due to confounding factors. Additionally, anxiety can have either beneficial or detrimental effects on important cardiac outcomes (e. It leads to activation in some and avoidance in others depending on level of anxiety and personality characteristics. Many have shown a positive effect on psychiatric symptoms and quality of life but equivocal effects on cardiac outcomes and mortality [30,31]. Firm links between anxiety and hard cardiac endpoints over the long term remain unproven, limiting development of definitive treatment guidelines. However, patients who require prolonged mechanical ventilation have longer hospital stays, face higher morbidity and mortality, and require lengthier rehabilitation. Given the limitations of communication and easy fatigability in patients with critical illness, the evaluation of anxiety in this setting remains difficult. This difficulty extends to research efforts attempting to define the incidence of and factors leading to anxiety in the setting of ventilator weaning. Approximately 25% and 56% of patients experience symptoms of acute and chronic anxiety, respectively, related to mechanical ventilation . Although the physiological measures used to determine readiness to wean from the ventilator are well known and several of them have been studied closely in clinical trials, information about the effect of the patient’s psychological state, specifically anxiety, on weaning from the ventilator is scant. Given the extensive overlap between physiological effects of anxiety and those of respiratory muscle fatigue, it can be difficult to separate ventilator weaning failure from anxiety. Anxiety may cause shortness of breath and a fear of death or abandonment, especially as ventilatory support is withdrawn. This can stimulate the sympathetic nervous system; cause bronchoconstriction; and increase airway resistance, work of breathing, and oxygen demand. Anxiety should be considered for all patients during the weaning process, especially those who are intubated for primary respiratory causes and for a prolonged period. Given the paucity of data regarding the effect of anxiety on ventilator weaning, no clear treatment guidelines exist; however, it is well appreciated that weaning should be approached from a multidisciplinary standpoint. Treatment includes pharmacological, environmental, and educational approaches; it is enhanced when patient, family, physicians, and nurses are involved in the decision to wean and in the process of weaning. Because anxiety and respiratory distress due to fatiguing respiratory muscles can produce similar cardiorespiratory manifestations, disentangling the two is critical. Only if one is convinced that anxiety is the cause should one consider pharmacotherapy for anxiety because pharmacotherapy with benzodiazepines can potentially prolong weaning due to suppression of respiratory drive. Although this class of medications is associated with respiratory suppression and altered level of consciousness and may lead to drug-induced delirium, benzodiazepines can be quite effective when used judiciously in the correct setting. Neuroleptics are less associated with respiratory suppression and may be more beneficial than benzodiazepines, especially for patients whose weaning failure is due to fear or delirious agitation. In addition to benzodiazepines and neuroleptics, dexmedetomidine, an α2-adrenergic receptor agonist, is increasingly being used. The lack of respiratory-suppressant effects allows patients to be extubated while remaining on dexmedetomidine, whereas benzodiazepines require discontinuation or reduction prior to extubation. The greater success in extubation appears to be more pronounced in patients who had failed previous conventional extubation attempts . Therefore, dexmedetomidine is a reasonable option for anxious patients who are at high risk for ventilator weaning failure. Nursing should remain as consistent as possible with an individual patient; during active weaning, a 1:1 nurse-to-patient ratio should be maintained. Weaning is more successful when patients are aware of their environment and engaged in discussions of the plan and process of weaning. Patients should be told and reminded that weaning without extubation does not represent a failure but is part of the process. In addition, medications used to treat a pre-existing anxiety disorder may be discontinued on admission, or their bioavailability may be altered by interactions with newly prescribed medications. Both discontinuation and pharmacokinetic changes may significantly worsen pre-existing primary anxiety disorders. Symptoms are clustered into four categories: re-experiencing, avoidance, negative thoughts/mood, and arousal . Re-experiencing manifests in dreams, intrusive memories, flashbacks, or intense distress when exposed to reminders of the event. Negative thoughts/mood may include a distorted sense of blame of self or others, diminished interest in activities, or an inability to remember key aspects of the event. Arousal symptoms can include aggressive, reckless, or self- destructive behavior; sleep disturbances; and hypervigilance. Although there is a lack of randomized controlled trials to support their widespread adoption, both bedside psychological interventions (e. Clinicians should identify and treat delirium, make efforts to reduce unnecessary sedation, and help orient patients to what is happening around them. These can be addressed with appropriate pain assessment and management, allowing patients more choices in their care, and helping patients to communicate (e. Psychiatric consultation can be useful for both acute management and recommendations for outpatient treatment, especially in patients with pre-existing psychiatric illnesses. Panic Disorder Panic disorder is one of the most common psychiatric disorders in patients who are high users of medical services. As defined by the Diagnostic and Statistical Manual of Mental Disorders , a panic attack is a discrete period of fear or discomfort that develops suddenly, reaches a peak within 10 minutes, and is associated with the symptoms listed in Table 158. Panic disorder consists of recurrent panic attacks accompanied by persistent fear of having additional attacks, worry about the implications and consequences of the episodes, and a significant change in behavior related to the attacks. Many panic-disordered patients are hypervigilant to internal bodily stimuli, and some fear that their attacks indicate the presence of an undiagnosed, life-threatening illness. These concerns are assuaged only when the panic disorder is accurately diagnosed and effectively treated. Timely diagnosis and treatment of panic disorder can circumvent unnecessary medical procedures and decrease morbidity and mortality. Non-pharmacological methods that have been explored include education, environmental manipulation, muscle relaxation, and music therapy. Additionally, non- pharmacological modalities have the added benefits of limiting adverse side effects related to sedative-hypnotics in critically ill patients. Provision of ambient light, a clock, and a calendar promotes accurate orientation and a normal sleep–wake cycle. In addition, to foster a sense of control and mastery of their situation, patients should be made an integral part of decision-making. Whether these physiological changes translate into reduced mortality or improved quality of life remains unknown.
Many patients with end-stage organ failure are currently not even considered for transplantation (and consequently are not listed) because of the strict recipient selection criteria that are being applied—in part as a result of the severe buy 25mg strattera with amex, ongoing organ shortage generic 10mg strattera. The widening gap between available deceased donor organs and the number of patients waiting is a result of the explosive buy strattera line, increased use of organ transplantation therapy over the past 40 years (Tables 56 buy cheap strattera 25 mg on-line. The rates of consent granted by families of potential deceased donors range only from 0% to 75% and appear to vary widely among geographic regions and ethnic groups [10–12]. Lack of dissemination and poor presentation of information to the public, misperceptions in the general population regarding the beneficial nature of organ transplantation, and the necessity of organ recovery from deceased donors, as well as inappropriate coordination of the approach to families of potential donors contribute to the stagnation of the organ supply [11–13]. The role of physicians who care for critically ill patients in altering this current situation is crucial . This will maximize families’ opportunities to donate a family member’s organs and allow the families to experience the beneficial effects of donation for the bereavement process (Table 56. Intensive care and emergency medicine physicians are obligated ethically and morally to provide the best possible outcome for a very ill patient. However, after a potential donor has been identified, they are also obligated to seek the best possible outcome for patients with end-stage failure of a vital organ waiting for a transplant by attempting to ensure that organ donation occurs. It is becoming increasingly evident that implementation of critical pathways and standardized donor management protocols play an important role in this context [17–25]. Donation after brain death is the most common type of organ donation (currently over 80% of all donors belong in this category) . The diagnosis of brain death rests on the irreversibility of the neurologic insult and the absence of clinical evidence of cerebral and brain stem function. The details of the clinical examination that is required to unequivocally establish brain death are described in this chapter. Donation After Circulatory Death Donors (Formerly Known as Donation After Cardiac Death or Non–Heart- Beating Donors) Death is determined based on circulatory and respiratory criteria. Most commonly, families of unconscious patients with severe irreversible traumatic or cerebrovascular brain injury, who do not fulfill the formal criteria of brain death, decide to forgo any further care and wish to donate the organs of their family member. Circulatory and respiratory support technologies are discontinued in the critical care unit or the operating room and organ recovery is initiated once death has been pronounced by a physician not belonging to the organ recovery and transplant team . In the interest of minimizing warm ischemia time, flushing cannulas may be inserted and possibly even perfusion of internal organs with cold preservation solution might already be started while consent to proceed with organ donation is obtained from the patient’s family. Nevertheless, these considerations must be balanced with the right of self-determination based on an individual’s previously documented preferences and the final wishes of a competent patient family. Further debate by the medical community and general public is crucial to address these complex ethical issues and to maximize acceptance of organ donation [28,29]. Without such thorough consideration, the deceased donor concept and the donation system that is currently in place might be harmed or discredited. This phenomenon has been attributed to a variety of factors that include (a) the introduction in the early 1980s of the powerful immunosuppressive agent cyclosporin A, followed a decade later by tacrolimus, mycophenolate mofetil, and other new immunosuppressants; (b) the availability of antilymphocyte antibody preparations to prevent and treat rejection episodes (e. In addition, the availability of potent, yet nontoxic, antibacterial, antifungal, and antiviral agents has allowed opportunistic infections in immunocompromised transplant patients to be treated more effectively. In combination with refinement of surgical techniques, these factors have led to increasing success of solid organ replacement therapy. Thus, transplantation has become the treatment of choice for many patients with end-stage failure of the kidneys, liver, endocrine pancreas, heart, lungs, and small bowel. Successful hand, arm, larynx, and face transplants from deceased donors have also been reported [30–33]. Currently, the only patients who are excluded from undergoing transplantation are those with malignancies (metastatic or at high risk for recurrence) and uncontrolled infections, those who are unable to withstand transplant surgery, or those who have a significantly shortened life expectancy due to disease processes unrelated to their target organ dysfunction or failure. Kidney Currently, patients undergoing kidney transplants from deceased donors exhibit excellent graft survival rates (Table 56. Renal transplantation dramatically improves life expectancy and quality of life, decreases cardiovascular morbidity and mortality, and rehabilitates the recipients from a social perspective. Kidney transplants are also less expensive from a socioeconomic standpoint than is chronic hemodialysis. For pediatric patients with chronic renal failure, a functioning renal allograft is the only way to preserve normal growth and ensure adequate central nervous, mental, and motor development. Liver transplants are an effective treatment for many patients, pediatric and adult, regardless of the cause of liver failure: congenital (i. Currently, there are no reliable means to substitute, even temporarily, for a failing liver other than with a transplantation. Hepatocyte and stem cell transplants to treat fulminant liver failure and to correct congenital enzyme deficiencies are being studied but are presently not a clinical reality. Intestine Small bowel transplants are performed in patients with congenital or acquired short gut, especially if liver dysfunction occurs because of long- term administration of total parenteral nutrition and when difficulty in establishing or maintaining central venous access is limiting. If liver disease is advanced, a combined liver–small bowel or, in highly selected cases, a multivisceral transplant (liver, stomach, small bowel, with or without pancreas) can be performed . Pancreas and Islet Primary prevention of type 1 insulin-dependent diabetes mellitus is not possible, but transplantation of the entire pancreas or isolated pancreatic islets can correct the endocrine insufficiency once it occurs. Glucose sensor systems that continuously monitor blood sugar levels coupled with real-time command of an insulin delivery system (implantable pump) and bioartificial and hybrid biomechanical insulin-secreting devices are not yet universally available for routine clinical use. The only effective current option to consistently restore continuous near- physiologic normoglycemia, however, is a pancreas transplant [35–37]. Good metabolic glycemic control decreases the incidence and severity of secondary diabetic complications (neuropathy, retinopathy, gastropathy and enteropathy, and nephropathy). Most pancreas transplants are performed simultaneously with a kidney transplant in preuremic patients with significant renal dysfunction or in uremic patients with end-stage diabetic nephropathy. Selected nonuremic patients with brittle type 1 diabetes mellitus (with progression of the autonomic neuropathy or recurrent severe hypoglycemic episodes, and with repetitive episodes of diabetic ketoacidosis) can benefit from a solitary pancreas transplant (without a concomitant kidney transplant) to improve their quality of life and to prevent the manifestation and progression of secondary diabetic complications. Evidence suggests that a successful pancreas transplant can achieve these goals in uremic and in nonuremic recipients and decrease mortality . Results of transplanting alloislets from deceased donors are encouraging in the short term ; however, long-term results are less favorable . Heart Heart transplantation is the treatment of choice for patients with end- stage congenital and acquired parenchymal and vascular diseases and is recommended generally after all conventional medical or surgical options have been exhausted. Mechanical pumps, such as implantable ventricular assist devices or the bioartificial heart, have contributed to this success because they can also serve as a bridge during the time between end-stage cardiac failure and a transplantation. Heart–Lung and Lung Heart–lung and lung transplants are an effective treatment for patients with advanced pulmonary parenchymal or vascular disease, with or without primary or secondary cardiac involvement. This field has evolved rapidly since the first single-lung transplant with long-term success was performed in 1983 (Table 56. The significant increase in lung transplantations is mainly due to technical improvements resulting in fewer surgical complications, as well as to the extremely limited availability of heart–lung donors. Previously, many patients with end- stage pulmonary failure would have waited for an appropriate heart–lung donor. Bilateral single-lung transplants are specifically indicated in patients with septic lung diseases (e. Double en bloc lung transplants have been abandoned because of technical difficulties related to the bronchial anastomotic blood supply. The 55- mile-per-hour speed limit, stricter seat belt and helmet laws, advances in critical care, as well as the trend toward a deceleration of care in patients that have suffered a catastrophic brain injury have all had significant impacts on the number of brain-dead organ donors . In 2016, the three leading causes of death among deceased donors in the United States were cerebral anoxia (e. According to estimates, there are at least 10,500 to 13,800 potential brain-dead donors in the United States per year . According to a study, the overall consent rate (the number of families agreeing to donate divided by the number of families asked to donate) was 54% in the United States, and the overall conversion rate (the number of actual donors divided by the number of potential donors) was 42% . The single most important reason for lack of organ recovery from 45% to 60% of the potential donor pool is the inability to obtain consent [12,24]. Several studies have shown that family refusal to provide consent and the inability to identify, locate, or contact family members to obtain consent within an appropriate time frame are the leading causes for the nonuse of many organs from potential donors [10–13,24]. A public opinion survey showed that 69% of respondents would be very or somewhat willing to donate their organs, and 93% would honor the expressed wishes of a family member . Moreover, 37% of respondents did not comprehend that a brain-dead person should be considered dead and unable to recover, and 59% either believed or were unsure whether or not organs can be bought and sold on the “black market.
Three more severe delayed outcomes have also been observed: (a) comatose state with minor neurologic improvement and death; (b) early neurologic recovery discount 25mg strattera overnight delivery, followed by cerebral edema with uncontrollable uncal herniation and severe morbidity or mortality; and (c) complete neurologic recovery cheap 40mg strattera otc, followed by delayed encephalopathy and death  buy strattera 25mg. Approximately 400 people per year are affected by lightning strikes order discount strattera on-line, with one-third of victims dying owing to their exposure . Pathophysiology Electrical and lightning injuries are exceedingly variable and dependent on a number of factors. Current flowing between two potentials, or amperage, is equal to the voltage divided by the resistance to current flow (I = V/R). Alternating current has a tendency to produce tetanic contractions that prevent voluntary release from the current source, thus prolonging the electrical contact time and increasing the potential for injury. Higher voltages, such as those that occur with lightning or with contact with high-voltage conductors, produce more severe injuries than those caused by lower voltages. Wet skin and tissues high in water content provide low resistance to current flow and are at a higher risk for injury, whereas tissues high in fat and air, such as hollow organs, provide high resistance. Nerves and blood vessels have lower than expected resistances, and thus are more sensitive to electrical injury than their water content would suggest . Finally, “stride current” involves the spread of electricity from the lightning bolt to the ground and then through contact points in the patient. Stride current patients are more likely to experience spinal cord injuries, because the current crosses through the spinal cord from one limb to another. Neurologic Complications of Electrical and Lightning Injuries Neurologic sequelae of electrical injuries affect both the central and peripheral nervous systems, with both immediate and long-term difficulties. Immediate Effects Immediate neurologic effects of electrical injuries are noted throughout the neuraxis. Patients with electrical and lightning injuries to the head may also suffer subarachnoid or parenchymal hemorrhages, particularly in the basal ganglia and brainstem . In patients who suffer cardiac or respiratory arrest, posthypoxic encephalopathy may develop in “watershed” areas of the cerebral cortex. Catecholamine release may result in autonomic dysfunction, as evidenced by transitory hypertension; tachycardia; diaphoresis; vasoconstriction of the extremities; and fixed and dilated pupils . Thus, lightning-strike victims should receive full resuscitative efforts despite pupillary changes, because these may not indicate permanent brainstem dysfunction. Lightning-strike victims may also suffer “keraunoparalysis,” a self-limited paralysis more often involving the lower extremities, accompanied by a lack of peripheral pulses, pale and cold extremities, and variable paresthesias . The spectrum of spinal cord injuries includes paralysis, spasticity, autonomic dysfunction, and, later, chronic pain and pressure ulcers . Acute neuropathies are typically not seen with lightning strikes, but may be seen with electrical injuries in association with compartment syndromes, local burns, or vascular injury . Both electrical and lightning-strike victims are vulnerable to the subacute development of cataracts, whereas lightning-strike patients are peculiarly susceptible to tympanic membrane rupture; vertigo; and hearing loss [22,23]. Recognized neuropsychiatric effects include depression; posttraumatic stress disorder; fatigue; irritability; and memory and concentration difficulties . Movement disorders have also been described, such as transient dystonias, torticollis, and parkinsonism . Delayed ophthalmologic and otologic consequences include cataracts, conductive and sensorineural hearing loss, and vertigo [22,23]. Delayed autonomic dysfunction may manifest as reflex sympathetic dystrophy, presenting as a limb with burning pain, cutaneous vasoconstriction, swelling, and sweating . Prolonged and permanent spinal cord abnormalities may become manifest in the delayed development of a myelopathy or a motor neuronopathy [14,25]. Peripheral neuropathies may result from compression due to scarring and fibrosis from the original injury or delayed ischemia due to vascular occlusion . Peripheral neuropathies are more likely to occur in areas directly involved by the electrical current, but may also occur in limbs that were not seemingly in the current path . Contrary to conventional mythology, lightning-strike victims are not electrically charged and may be examined immediately. Cardiac arrhythmias and asystole commonly accompany these injuries, as does respiratory arrest due to passage of current through the brainstem respiratory centers. Stabilization of the spine is also essential, owing to potential spinal cord injuries and fractures from falls. Neurologic Examination the neurologic examination should begin with assessment of the level of consciousness. Initially, many patients are comatose, but this is often brief and followed by a period of confusion and amnesia, lasting hours to days . The cranial nerve examination may reveal fixed and dilated pupils; blindness; papilledema; partial hearing loss; and tinnitus. Evaluation of the motor system for focal weakness and reflex changes may indicate cerebral injuries, myelopathy, or neuropathy. Peripheral nerve injuries in the immediate assessment are typically located in areas of extensive burns. Laboratory Evaluation Laboratory evaluations should be focused on the known complications of electrical and lightning injuries. Serial determinations of electrolytes, renal function, and hematocrit are essential for assessing adequate fluid replacement. Radiologic examinations of the long bones, spine, and skull are indicated when fractures or deep burns are suspected based on the history and physical examination. Cranial imaging is indicated when there is prolonged alteration of consciousness and may reveal intracranial hemorrhages, cerebral edema, or the effect of diffuse cerebral hypoxia. Nerve conduction studies and electromyography may be useful in localizing and following axonal and demyelinating electrical injuries to the peripheral nerves and plexi, although they are not generally used in the acute evaluation. Efforts should focus on circulatory volume, hydration status, renal function, acidosis, and electrolyte balance. Because high-voltage electric shock victims usually have myoglobinuria secondary to burns and deep tissue injury, their fluid needs are similar to those of crush injuries. Ultrasongraphic assessment of volume status can be helpful and urine output should be maintained at greater than 0. Alkalinization of the urine and osmotic diuresis with mannitol also help to prevent myoglobin nephropathy. Extensive burns due to direct current or clothing ignition are best treated in specialized burn units. Debridement of necrotic muscle and fasciotomy are sometimes necessary to prevent secondary ischemia from a compartment syndrome. Recurrent seizures are treated with phenytoin (18 to 20 mg per kg loading dose followed by 5 to 7 mg/kg/d). Because fluid restriction is contraindicated, patients with signs of increased intracranial pressure require osmotic diuresis with mannitol. Specific treatment for electrical spinal cord injuries is not available, and early institution of physical therapy is recommended. Patients with deficits at presentation might potentially recover fully, whereas those with delayed onset of neurologic deficits may have syndromes that progress over months to years. Carbon monoxide is a byproduct of incomplete combustion and as such is found in automobile exhaust, fires, water heaters, charcoal-burning grills, methylene chloride, volcanic gas, and cigarette smoke. It is also endogenously formed from the degradation of hemoglobin, resulting in baseline carboxyhemoglobin saturation between 1% and 3% . For further information on the pathogenesis, diagnosis, and treatment of carbon monoxide poisoning, see Chapter 178. Of note, the carboxyhemoglobin levels are not indicative of the severity of toxicity and depend on factors such as duration of exposure, comorbid conditions, and ambient carbon monoxide concentration . With mild intoxication, symptoms may include a mild headache; dyspnea on exertion; and fatigability . With increasing levels of toxicity, more severe symptoms may include impaired motor dexterity; blurry vision; irritability; weakness; nausea; vomiting; and confusion . At its most severe, carbon monoxide exposure may cause tachycardia; cardiac irritability; seizures; respiratory insufficiency; coma; and death . In addition, there can be evidence of rhabdomyolysis, flame-shaped superficial retinal hemorrhages, and, occasionally, a cherry-red discoloration best appreciated in the lips, mucous membranes, and skin [29,31,32]. For mild carbon monoxide intoxication, in which there is no loss of consciousness and carboxyhemoglobin levels are less than 5% in nonsmokers or less than 10% in smokers, only headache and dizziness around the time of presentation were found to correlate with an increased incidence of delayed sequelae, including asthenia, headache, or decreased memory . The electroencephalogram usually demonstrates diffuse slowing but is generally of little prognostic value. Treatment the criteria for hospital admission include coma, loss of consciousness, or neurologic deficit at any time; any clinical or electrocardiographic signs of cardiac compromise; metabolic acidosis; abnormal chest radiograph; oxygen tension less than 60 mm Hg; and carboxyhemoglobin level greater than 10% in individuals with pregnancy, greater than 15% in those with cardiac disease, or greater than 25% in all other patients .