4 Ways to Manage -- from the Sick BedGet ready to delegate, over-communicate and get the rest you need.

What happens when a manager becomes too sick, or too injured, and can't effectively manage anymore? Many companies fail to plan for these kinds of scenarios, which can cause serious damage if the right steps aren't immediately taken.

In some cases, especially when an entrepreneur oversees the daily operations of a small business, the lack of support from at least one reliableemployeecan "lead to some form of collapse of the enterprise," says Peter Bryant, who holds a PhD in management and is a professor of entrepreneurship atIE Business Schoolin Spain. In other situations, warns Bryant, the work gets delegated to whoever might be available, "which is often not the best option because they might be a relatively junior person." Here's how to avoid certain mistakes, or at least lessen the damage, in these kinds of situations:

Set those notifications.It's simple, but effective: activate an "out of office" email alert and record an answering machine message that notifies individuals you're away for health-related reasons. This tactic might have prevented Vannessa Wade from missing out on new business. The chief executive officer ofConnect the Dots PR, a Houston-based public relations firm, suffers from Sickle cell disease, which unexpectedly leaves her exhausted or pains her arms, legs or chest. During one debilitating episode, Wade failed to tell a prospective client who contacted her that she would be away for a couple of days. By the time Wade got back to the individual it was already too late. "The person actually said "you didn't respond fast enough, and we're going to go with another public relations company," says Wade.

Find a replacement.While it's unlikely that every client will leave during an executive's health crisis, some will hesitate to stay. That's why experts recommend quickly finding a replacement to help manage aspects like customer service and business development. When it was just a one-year-old insurance startup,Petplan's team got put to the test after its co-chief executive officer Chris Ashton shattered his ankle and broke his ribs in a 15-foot fall. He was lucky enough that his wife and co-chief exec, Natasha, could step in.

Yet, over the course of about five months, the company had to grapple with Chris' constant absence as he underwent multiple surgeries, dealt with unanticipated blood clots and needed time to recover. That led Natasha to delegate additional day-to-day duties to a senior manager. "He fielded more than he was used to and took on more responsibility, enabling him to tackle calls and build business relationships that he previously hadn't had as much," says Natasha, 40, whose company earned $53 million in revenue last year. The key to this strategy's success: having introduced the manager to everyone he would be dealing with.

Know your limits. Given the uncertain economy, and the propensity for some human resource officials to skip over resumes with breaks between gigs, it's not hard to see why many ill managers try to stay in the game—even when they might be better off resting on the sidelines.

If Tron Jordheim could manage the dozen employees he used to oversee at a water-bottling dealer all over again, he would do it differently—by being less hands-on and fostering more independence. Back then, following a diagnosis with testicular cancer, the former sales manager spent eight months in and out of chemotherapy—and in and out of work — as he leafed exhaustedly through route logs and rode miserably with bottled water drivers. "I didn't want to lose my place in the company," says Jordheim, who is now the chief marketing officer ofStorageMart. "I went to the office just to show my face, even though I couldn't really do a whole hell of a lot. I'm not sure that brought anyone any value."

Prepare for relapses.Owners of smaller, cash-strapped firms often try to do it all—and understandably so. But trying to be a Jack or Jill of all trades can not only worsen your health, it might also jeopardize client relationships if there are too many relapses in the future and trustworthy replacements are hard to find.

Wade has spent the past few years cultivating relationships with other public relations contractors, including writers, branders and photographers in case her disease ever requires her to take rest again or revisit the hospital. "They'll say "we can take handle it since you're not feeling well,'" says Wade. "It makes a difference and gives you clarity, and it reminds me you're not on earth to do things all alone."