The only drugs required for most hand surgery procedures are lidocaine (also called lignocaine) and epinephrine.

Lidocaine was introduced in the late 1940s, and in the intervening 65 years, American dentists have injected lidocaine premixed with epinephrine in an average of more than a million patients per day with no monitoring, no intravenous insertion, and no preoperative testing and have reported very few adverse reactions.1,2 If there were common or serious problems with lidocaine and epinephrine injection, the American legal community would have been seeking financial compensation for their clients from dentists long ago.

The maximal dose of lidocaine with epinephrine, published before 1950, is 7 mg/kg. Since then, Vasconez and others have reported safe blood levels of lidocaine when they injected 35 mg/kg for liposuction.3,4

Lidocaine is much less cardiotoxic than other local anesthetics such as bupivacaine or ropivacaine (see the section on longer-lasting local anesthetics). In fact, internists commonly inject lidocaine to rescue ventricular arrhythmias.5

A PubMed search for lidocaine anaphylaxis reveals six case reports in the past 7 years. Two of the six cases had incomplete details,6,7 and the remaining four had other confounding variables, which made it hard to attribute the anaphylaxis solely to the lidocaine.8–11 These reports are rare when you consider the billions of lidocaine doses administered in dental offices in the world in six and a half decades. If life-threatening anaphylaxis to lidocaine actually does exist, it is likely to be extremely rare.12

Emergentologists inject lidocaine in 100 mg slow intravenous boluses to treat various pain conditions.13 Anesthesiologists inject 1 mg/kg of lidocaine intravenously for pain control in postoperative patients.14 Inadvertent intravenous small boluses of local anesthetic may occur with antegrade injection, as described in Chapter 4. However, toxicity from these tiny intravascular doses is very unlikely.

Lidocaine-induced seizures can occur with large intravenous doses administered too quickly, or with excessive doses injected subcutaneously. With the doses and slow injection technique outlined in Chapters 4 and 5, this complication is likely to be rare or nonexistent. The treatment of lidocaine-induced seizures is conservative management.15

The antidote for lidocaine toxicity is the lipid emulsion Intralipid. It has very limited use, because people rarely need it. It is not a perfect antidote.16,17 The mechanism of action of lipid emulsion therapy for lidocaine toxicity is not well defined. It has been postulated that it works by a “lipid sink,” decreasing circulating amounts of drugs to the periphery, or through a direct “energy source” to the myocardium.5

The antidote of epinephrine vasoconstriction is phentolamine. The myth that epinephrine vasoconstriction is dangerous in fingers is addressed in Chapter 3. This chapter only deals with the systemic effects.

The medical literature is almost devoid of reports of serious systemic adverse reactions to the epinephrine that accompanies the lidocaine, even in patients with cardiac disease.18 However, if there is a concern about giving a patient with cardiac disease epinephrine-containing local anesthetic, we can monitor these patients and give them lower dosages of epinephrine.

Clip 6-1 shows an 84-year-old man with cardiac issues who was given a lowered epinephrine concentration in the hospital with monitors during WALANT surgery for EI to EPL tendon transfer, with a good result.

Epinephrine still provides good hemostasis in doses as low as 1:400,19 or 1:1,000,000.20 We routinely use 1:400,000 epinephrine when we need 100 to 200 ml of volume for larger cases and find the hemostasis perfectly acceptable, as long as we give the epinephrine half an hour to work.

Epinephrine in a local anesthetic can cause transient elevation of the heart rate and blood pressure, but the clinical importance of this effect remains unclear.5,21 Adverse outcomes among hypertensive patients are infrequent, and hemodynamic outcomes, which are possible risk indicators, reflect only minimal change.17

Ropivacaine and bupivacaine both last longer than lidocaine, but they have a lower safety profile. In large doses, bupivacaine22,23 and ropivacaine24,25 can be cardiotoxic and fatal. Lipid emulsion therapy has been used for both bupivacaine26 and lidocaine27 rescue.

For digital blocks, bupivacaine-induced useful numbness to pain lasts only half as long (15 hours) as the annoying pressure and touch numbness (30 hours).28 That is why patients with bupivacaine digital blocks complain that their injured finger is still numb, but it hurts.

Lidocaine pain and numbness to touch and pressure all come back at the same time, like an on/off light switch.

You can finish most hand operations in the anesthesia time provided by lidocaine with epinephrine (5 hours in the wrist,29 10 hours in the finger30). We use bupivacaine only in operations that may last more than 2½ to 3 hours or in procedures such as a trapeziectomy, where postoperative pain may be severe.