Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of hospital staffing provider IPC The Hospitalist (Nasdaq: IPCM) could instead use a gurney themselves today, falling 30% after the company updated its full-year guidance.

So what: IPC, as clearly evidenced by today's tumultuous drop, cut its full-year EPS forecast, down to $1.70-$1.74 from its own previous guidance of $1.78-$1.86. Sales expectations also fell to a range of $455 million-$458 million, down from earlier guidance of $463 million-$465 million. IPC blamed unexpected softness in patient volumes in certain areas of the U.S. and the use of temporary staff at some of its larger locations as the reason for the profit shortfall.

Now what: IPC's warning after the bell on Friday marked the third straight quarter profits have failed to hit their mark. Prior to updating its guidance, IPC was trading at 28 times trailing 12-month earnings, which is pretty expensive for a hospital staffing business -- even one that will grow sales by 26% in fiscal 2011. Today's warning simply reminds us that growth by acquisition doesn't always go as smoothly as you expect. Having completed 13 acquisitions last year, IPC clearly still has some kinks to work out. Personally, even after today's huge losses, I'm still not going anywhere near IPC until I see it meet or beat its own guidance.

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Fool contributor Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.