A PLLC allows you to function as a corporation utilizing minimal workforce, in an anesthesiologists case that's usually one person... the anesthesiologist.
The reasons for doing so are primarily to buffer the tax burden placed on high income earners, NOT for asset protection.
Now, PLLCs (and LLCs) are not recognized by the IRS, they're recognized at the state level and thus formed through your state secretary's office. The IRS only recognizes individuals, corporations, partnerships, and sole proprietorships as taxable entities with corporations being further divided in to either an S-corp or a C-corp based on number of employees.
Now, you simply cannot work without paying uncle sam, so you must declare your entity (in this case your PLLC) as a taxable entity by filling out IRS Form 2553 when you create your PLLC. It is to your benefit to classify your entity (PLLC) as an S-corporation so as to avoid double taxation (both your corporation and you getting taxed separately).
By running your practice as PLLC all collected income goes to your PLLC's business account. Out of this account you can pay for any and all business expenses (conferences including travel expenses, software, books, stethoscopes, business cards) out of the PLLC account. Your PLLC can also own and maintain a vehicle and pay for gas at a percentage of business miles driven. Your PLLC can also participate in profit sharing towards a retirement account. In my case, I have a SoloK (essentially a SEP IRA but with profit sharing), I contribute 33.3% of my income to retirement and my PLLC covers the remaining allowed 66.7% to maximize the allowable tax-free investment into a retirement account while at the same time allowing me to claim less income. Now, an interesting point is: in terms of salary, how much do you pay yourself out of your PLLC account for salary? In addition to seeking consultation with my CPA on this question, I also have a documented phone conversation with an IRS agent. Both provided the same answer--> the IRS does not give any formulas or guidelines for paying yourself a reasonable salary out of a PLLC but the tax code does say you must pay yourself a "reasonable" salary. Both my CPA and the IRS agent said the the current standard set by precedent is 50% of your PLLC's earnings. I have colleagues that pay way under this in order to remain in a lower tax bracket, but they're likely subject to substantial fines if they were to be audited. I could go on and on about PLLCs, but I hope this at least begins to elucidate the benefits of managing your practice with one.