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High altitude pulmonary edema (HAPE) is a severe form of altitude illness occurring in some inadequately acclimatized individuals as a result of rapid ascent to high altitude. HAPE is a noncardiogenic pulmonary edema that may be rapidly fatal and can occur with or without prodromal symptoms. Fast recovery is common, however, with early recognition and descent to a lower altitude. canadian pharmacy

Endotracheal intubation and mechanical ventilation are indicated in a variety of pulmonary, cardiovascular, and neurologic disorders to optimize ventilation and oxygenation as well as protect the airway. The role of prehospital intubation in the management of severe HAPE has not been previously discussed in the literature. This report presents a case of persistent HAPE that resulted in cardiopulmonary arrest following a 2,300 meter descent. The case was managed with endotracheal intubation and manual mechanical ventilation performed while the patient was in a remote area of the Nepal Himalaya.

Report of a Case
A 38-year-old Sherpa man, who was employed as a high-altitude porter for a commercial expedition and had a history of HAPE on a previous expedition, ascended from his resident altitude of 2,900 meters to the 5,300-meter base camp over 7 days. After residing in base camp for 3 weeks with frequent load carries up to 6,500 meters, the patient moved to 6,500 meters to work on improvements to the higher altitude camp. Over the subsequent 48 hours he was noted by teammates to be “lazy,” “sitting around,” and “not doing his share of work,” but he did not descend despite advice by team members to do so. On the third evening at this camp, the patient was noted to be confused and short of breath with a persistent cough productive of pink froth. Teammates suspected that he was suffering from life-threatening HAPE. After the patient received nifedipine tablets and dexamethasone and was started on oxygen therapy, he was taken back to base camp—a dangerous 7-hour night descent.

The patient arrived at the 5,300 meter base camp before midnight, and was examined by the expedition physician, who diagnosed severe HAPE. The patient was continued on nifedipine and dexamethasone, and remained on oxygen overnight. In the morning, the patient had not improved, and an attempt to walk him to a lower elevation failed when he collapsed just outside base camp. The patient refused continued oxygen administration or hyperbaric therapy, arguing that he did not have altitude sickness. By evening the patient still had not improved, despite being at an altitude at which he had resided for over 3 weeks without symptoms. After further medical consultation, oxygen therapy was restarted and antibiotic administration begun, and adalat nifedipine and dexamethasone were continued. A helicopter evacuation was arranged for the following morning, but bad weather precluded the flight early the next day. A strenuous ground evacuation was begun. This descent to Pheriche at 4,200 meters required 12 hours. The patient sat upright in a basket carried by porters and was attended by the expedition physician.

Upon arrival to a lodge at Pheriche, the patient was alert when aroused, and notably tachypnic with a persistent cough. His respiratory rate was 38 breaths per minute, with an oxygen saturation (Sa02) of 70% on 4 liters per minute oxygen via face mask. Rales were auscultated throughout both lung fields. The patient was placed supine in a portable hyperbaric chamber at 104 mm Hg above ambient barometric pressure for 1 hour. During the hyperbaric therapy, the patient experienced an apparent cardiopulmonary arrest, eventually noticed by a Sherpa who was managing the foot pump. After several minutes of cardiopulmonary resuscitation, the patient was intubated with equipment and assistance from the nearby Pheriche Aid Post, and return of a regular pulse was noted. A decision was made to sedate the patient and continue intubation and ventilation using an ambu bag with oxygen, given the difficulty of the intubation and the protracted course of HAPE over the previous 5 days, despite the 2,300 meter descent. Due to poor weather, helicopter evacuation to Kathmandu was delayed for 40 hours. Manual ventilation, sedation, and monitoring of Sa02 above 92% were continued. On the third day after admission to the hospital in Kathmandu, the patient was extubated without difficulty. His neurologic function remained markedly impaired, and the patient died in the hospital 2 months later. canadian cialis

Discussion
HAPE is a life-threatening emergency that requires early recognition and treatment. The consequences of delayed recognition, a lack of prompt action, and inadequate/inappropriate treatment are illustrated by this case. The complexity of this case of HAPE, which persisted despite eventual descent, and the subsequent tragic outcome call attention to the difficulties faced when managing emergencies at moderate and extreme altitude. canadian ampicillin

Oxygen administration and portable hyperbaric chamber treatment are adjuncts to, but not substitutes for, immediate descent to a lower altitude if feasible. HAPE typically resolves rapidly with descent. Descent of 500 meters to 1,000 meters is usually adequate, but descent should continue until symptoms resolve. Signs and symptoms occurring at high altitudes with 1) atypical onset, 2) unusual combinations, or 3) persistence after descent, have been described as indicators of possible diagnoses other than altitude illness. In this case, the lack of improvement after the initial 1,200-meter descent to base camp, where the patient had been previously well, indicates the possibility of more than a simple case of HAPE.

Other underlying conditions might be suggested to have complicated this case of persistent HAPE. Common pulmonary disorders that accentuate hypoxemia through worsening alveolar gas exchange from areas of shunt include pneumonia, pulmonary tuberculosis, pulmonary embolism, cardiogenic pulmonary edema, and acute respiratory distress syndrome (ARDS). ARDS resulting from HAPE has been reported. The presence of such primary- or co-morbidity could complicate expected resolution by descent of suspected HAPE. These conditions would have been unlikely to reverse after only 12 hours of mechanical ventilation, however, and are therefore unlikely to have been present in this case, as evidenced by the clearing of the lungs and markedly improved Sa02. generic albendazole

In this case of severe HAPE, descent was delayed for several days. After 5 days of severe tachypnea following the onset of HAPE, the patient experienced respiratory failure and subsequent cardiopulmonary arrest after eventual descent totaling 2,300 meters. The author postulates that the cardiopulmonary arrest resulted from prolonged respiratory insufficiency due to delayed early treatment resulting from lack of recognition of HAPE, further delayed descent when symptoms did not resolve at base camp as expected, and unnoticed clinical deterioration after electing to substitute continuous oxygen administration for hyperbaric chamber therapy in which the patient was laid flat. Continued hypoxemia from respiratory insufficiency due to fatigue and persistent pulmonary edema may have prevented clearing of HAPE despite subsequent descent, leading to respiratory failure as the cause of the cardiopulmonary arrest.

Hypoxic-ischemic encephalopathy likely occurred as a result of the initial delay in detecting the cardiopulmonary arrest during portable hyperbaric chamber therapy. This delay ensued because patients cannot easily be managed in a portable hyperbaric chamber. Oxygen therapy has been found to be equally as effective as hyperbaric therapy in moderate to severe HAPE, and allows ease of access for monitoring the patient. Large quantities of oxygen, however, are not easily available in remote areas. One solution to this problem is the use of a portable hyperbaric chamber matched with the use of continuous-pulse oximetry monitored through the chamber window.  omnicef antibiotic

The role of prehospital endotracheal intubation and manual mechanical ventilation in acute respiratory arrest from HAPE alone is unclear. The pulmonary oxygen diffusion impairment, secondary to such a severe degree of pulmonary edema, would be unlikely to improve from manual mechanical ventilation alone (without positive end expiratory pressure); thus significant improvement in gas exchange and oxygenation is unlikely. In the case of respiratory insufficiency/arrest due to fatigue and pulmonary edema, however, such as that suspected in this prolonged case of HAPE, ventilatory support might be argued for in order to improve oxygenation by increasing the fraction of inspired oxygen and converting previous areas of shunt to areas of gas exchange. The difficulties of managing a critically ill patient with endotracheal intubation and manual mechanical ventilation are monumental in the protracted prehospital setting of very remote areas. Oxygen saturation monitoring provides guidance regarding blood oxygenation, but information concerning the effectiveness of the ventilation, specifically the acid-base status, is conspicuously lacking.

Conclusion
Although HAPE can be easily reversible if it is recognized early and prompt descent is undertaken, HAPE can be fatal if unrecognized or ignored. The need for early recognition of HAPE as a respiratory emergency at high altitude, prompting immediate descent, may be underappreciated by some physicians. Ultimately, the responsibility for prevention and early recognition of altitude illness rests with the high altitude sojourners themselves. Often, the greatest threat facing climbers is their own failure to accurately assess a dangerous situation and respond appropriately. prednisolone

A patient’s failure to improve after initial descent must alert the care provider to consider additional causes of pulmonary compromise, while continuing descent, rest, oxygen therapy, and evacuation efforts. Further descent can only help any illness at high altitude. Oxygen administration has the benefit of easier patient monitoring and access compared to portable hyperbaric chambers. Chambers also force the patient into a supine position although this can be overcome by propping up the head of the inflated chamber. Prehospital endotracheal intubation and mechanical ventilation may be considered in the management of acute respiratory failure following HAPE and other emergencies in remote settings.