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 Masimo (Nasdaq: MASI) fell nearly 19% in early trading and remain off more than 10% as of this writing. Third-quarter results came in below expectations. Management also cut its full-year outlook.

So what: Revenue grew 3% to $104 million, yet profits fell to $0.24 a share from $0.27 in last year's third quarter. Analysts had expected the maker of blood-monitoring instruments to produce $0.27 a share on $109.7 million in revenue, according to data compiled by Yahoo! Finance. The message? Five-star rating or not, few medical device makers can deliver the way Intuitive Surgical (Nasdaq: ISRG) does.

Now what: Unfortunately, the story didn't end there. Management compounded the miss by lowering its full-year forecast to $1.04 to $1.06 in per-share earnings on $436 million to $439 million in revenue. Both estimates were well off the bottom end of earlier guidance and what Wall Street expected. Does it matter? Would you buy shares of Masimo now that the stock trades for less than analysts' consensus long-term estimates for profit growth? Please weigh in using the comments box below.

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Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. He didn't own shares in any of the companies mentioned at the time of publication. Check out Tim's portfolio holdings and Foolish writings, or connect with him on Google+ or Twitter, where he goes by @milehighfool. You can also get his insights delivered directly to your RSS reader.

The Motley Fool owns shares of Masimo. Motley Fool newsletter services have recommended buying shares of Intuitive Surgical. Try any of our Foolish newsletter services free for 30 days. We Fools may not 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.