‘You sit there with a machine that pumps an Albuturol mist into your lungs.”

I ask, “Did you have a mask on?”

“No. It’s like a pipe.” Speaking is a woman I’ll call Margaret, an old friend. She, her husband, and I are at table in the Base Camp Cafe, a tourist restaurant in Mammoth Lakes, California. Aforesaid restaurant and town are set 8,000 feet up in the sky.

Margaret is telling me about her trip to the medical clinic. She awoke to high altitude sickness yesterday morning, specifically: 24-hour headache, lethargy, difficulty breathing, difficulty walking, and difficulty climbing stairs. Margaret continues, “And you breathe in and you breathe out. This expands the bronchial tubes in the lungs.”

“Does that test your oxygen level?”

“No. After I did that for about 20 minutes,” Margaret says, “that’s when they came in and checked the oxygen level of my blood again. They put a clip on the end of your index finger. Then they had me stand up and blow into that little thing that looks like a horn. It’s called a peak flow meter.”

Margaret arrived with an oxygen level of 83. “How high was it when you left?”

“It was up to 94,” Margaret says. “It’s supposed to be 98. If it hadn’t gone up, and gone up quickly, they were going to send me back to sea level.”

This unscheduled medical detour cost $1,000 — $500 for doc, $500 for prescriptions. What’s strange is that my friends are experienced hikers, have trotted around at high altitude on many occasions, and never had a problem. This trip we three experienced symptoms. Hers were serious.

The idea was to frolic at the Mono Basin Bird Chautauqua. It’s a three-day birding event headquartered in Lee Vining, a sweet, undeveloped town next to Mono Lake, 30 miles north of here. And yet, somehow, the weekend went in another direction.

A waitress, tall with biker-blonde hair, comes by our table waving a coffee pot. Asked if a lot of people get altitude sickness, she replies, “A lot, a lot of people do.”

* * *

I am standing in the emergency room of Mammoth Hospital talking to Lori Baitx, RN. She is the ER manager and has been working here for 26 years. Baitx is five-foot-eight, with shiny bob-cut silver hair, country smile, perfect tan, dressed in a blue hospital smock and sneakers.

Baitx says, “We don’t see a lot of people [with altitude sickness]. We do see it regularly, but I wouldn’t say a lot of people.”

“About how many in a typical week?”

“More like one or two a month.”

“Is there a profile? Are people with altitude sickness of similar age, sex, physical condition...?”

“No, and that’s one of the interesting things about high altitude illness,” Baitx says. “Someone can come up here 99 times and it’s the 100th time they get sick. And they might not get sick again when they come back up. It’s just one of those weird, freak things — for some reason people get sick.

“There are probably tons of people who have headaches and shortness of breath, but we don’t see those people. We generally see the worst, which include high altitude pulmonary edema, where the lungs begin to fill with fluid. That’s a life-threatening thing. The only cure for it is to get out of the altitude.

“There’s also high altitude cerebral edema, where your brain begins to swell. That’s the kind of thing you’ll see up at Everest, but occasionally we see it here. We can do temporary measures — put them on oxygen and do some other things — but we need to get them out of here as quickly as possible. That’s the treatment.”

“Is there any danger in going down too fast?”

“No. What we usually do is send them down on oxygen. We put them on high-flow oxygen for the trip down to Bishop. Once they hit Bishop, they get checked again to see if their oxygen saturation has come up. Usually they’re cured by the time they get there.”

“What’s the elevation of Bishop?”

“Four thousand.”

I ask, “Is there a point with [cerebral or pulmonary] edema where you’re just out of luck?”

“People die of high-altitude pulmonary edema and cerebral edema,” Baitx says. “It could get to the point that going down in altitude [doesn’t help, because] things have progressed too much and people die. We usually have, maybe, one death a year from high altitude pulmonary edema.”

“And that could be a 35-year-old guy or a 70-year-old guy or anything in between?”

“That’s the thing that’s so weird about it.”