Monday, December 13, 2010

"Donald" from Weaning the Vent

So, it was close to noon by the time we made it to Bed One, where we found a toddler named Donald Merrill. Donald Merrill was, for the moment, my only patient. It was my turn to lead the team. I was fortunate to have inherited a light load of patients, but that would soon change. I was on call that day and night and any kids admitted in the next eighteen hours would be primarily my responsibility. For now, however, Donald was it. I was preoccupied with the morning’s events, namely the disturbing visage of the girl in Bed Seven and Karl’s antics, and so when we arrived at Donald’s bedside I made a rookie mistake.

“Donald Merrill is a three-year-old male admitted from Sutter Delta,” I began “for pneumonia with hypoxia. The patient was brought in by Life Flight with an oxygen sat of seventy percent, but with otherwise stable vital signs. The patient initially presented to Sutter Delta Medical Center with two days of fever and congestion and was found to have a room air sat of ninety-two and an interstitial infiltrate on chest X-ray. He received one gram of Rocephin and was transferred to UC Davis. Overnight, Donald has been on non-invasive ventilatory support with Bi-level positive airway pressure, BIPAP.”

Dr. Connor interrupted me. “Wait, wait.” He gesticulated sideways, as if he might break into the electric slide. “Before you continue, please tell us what Donald’s underlying condition is.” I knew the answer and was about to respond, but someone else beat me to it.

“Ondine’s curse, also known as CCHS, Congenital Central Hypoventilatory Syndrome.” It was Karl. He just couldn’t help himself. “It comes from Greek mythology.”

Dr. Connor coughed loudly, but Karl continued. “The name comes from the tale of the Ondine, a beautiful water nymph. Ondine was wronged by a young lover and in revenge she cursed him. The curse…” Karl appeared ready to launch into a lengthy explanation. Dr. Connor appeared ready to burst a temporal vein.

“Doctor Krumholz,” Dr. Connor cut him off, “let’s allow Doctor Ballard to educate us about Congenital Central Hypoventilation Syndrome.” Karl nodded and flipped his hair again. Dr. Connor grunted, “Doctor Ballard?”

I told the team what I knew about CCHS, which wasn’t much. “CCHS is a rare condition, a genetic disorder,” I stammered, “one that affects automatic respiration.” Later, I would research the condition and its associated mythology. Karl was right, at least mostly right. Ondine was a water nymph, born in 18th-century German, rather than Greek, mythology. She was beautiful, enchanting, and extremely leery of men. Ondine, like other nymphs, could lose her everlasting life under only one circumstance: if she fell in love with a mortal man and bore his children. Despite her caution, Ondine fell in love with handsome young Palemon, who broke off his engagement to a noblewoman to marry her. On their wedding day, Palemon vowed, “My every waking breath shall be my pledge of love and faithfulness to you.” Years later, lovely Ondine bore Palemon a child, a son, and in doing so forfeited her immortality. Immediately, she aged and her transcendent beauty faded. Palemon’s eye wandered and on a fateful afternoon, Ondine heard the familiar sound of her lover’s snore in the stable on their estate. Entering, she found him entangled in a post-coital embrace with his former fiancĂ©e. Enraged, Ondine kicked Palemon and uttered a magic curse: “You pledged faithfulness to me with your every waking breath, and I accepted that pledge. So be it. For as long as you are awake, you shall breathe. But should you ever fall into sleep, that breath will desert you.” And so it was that Palemon’s next sleep, preceded by complete exhaustion, was his last. In the 1960s surgeons discovered a condition, following spine surgery, in which patients lost their spontaneous drive to breathe after falling asleep, and it was named after the mythical curse of Ondine. But at the moment, as I boiled with disappointment at Karl’s interruption, I didn’t know any of that.

Since its discovery, a genetic form of Ondine’s Curse had been found – linked in over 90% of cases to mutations to the PHOX2B gene and occurring in one out of 200,000 live births. Most victims died quickly, usually as infants. Donald Merrill was one of only 200 known living patients with CCHS.

Donald had survived to age three for a couple reasons. First, his mother also had CCHS so his family knew, even before he was born, that Donald was at risk. This allowed Donald’s physicians to make the diagnosis before it had fatal ramifications. Secondly, like his mom, Donald had a relatively mild form of the disease. He needed constant respiratory support when sleeping, otherwise his breathing became too shallow. But unlike some (approximately one out of every ten) with Ondine’s Curse, Donald did not need any when he was awake. None, that is, unless his lungs were compromised in some way, such as with an illness like pneumonia.

As we reviewed his situation, Donald was asleep in the room. I knew his family situation was complicated – the note from Sutter Delta mentioned that his mom was in treatment for heroin abuse, so I wasn’t surprised that he was alone. Pale and thin, with flat brown hair pressed onto his forehead, he looked sickly, although not critically ill. He wore an oval-shaped mask over his nose and mouth. When Donald exhaled, the mask clouded with mist. His breathing was even and peaceful. It looked normal, but I had to remind myself that if it were not for the mask, Donald might forget to breathe.

Donald’s care was pretty simple, and conscious of the length of our morning rounds, I summarized concisely. “We will continue antibiotics, await cultures and continue BIPAP at 12/4.”

“Wait, wait,” said Connor. “Doctor Ballard, it is important that you are precise. Imprecision is precisely the cause of most medical errors. What, precisely, are the antibiotics and what rate is the BIPAP set at?”
Yikes, more embarrassment. But he was right; the rate of the BIPAP respiratory support was critically important. Normal BIPAP merely assisted each inspiration and expiration with pressure that helped force air into and out of the lungs. But, this alone would not help Donald. He needed his breaths to be triggered on a regular basis. Thus, his BIPAP was set at a pressure of 12/4 (inspiration/expiration) and a rate of ten breaths a minute. I was about to correct my error, when we were interrupted.

“Bed Seven,” said a weathered nurse in pink scrubs, “she is hypotensive and de-sating. I’m worried about her. You need to look at her now.”