Cardiovascular effects of intraosseous injections of 2 percent lidocaine with 1 : 100,000 epinephrine and 3 percent mepivacaine

Background. Because a number of patients have reported an increase in heart rate with the intraosseous, or IO, injection, it is important, to evaluate changes in the cardiovascular system with this injection technique. The pu rpose of this study was to determine the cardiovascular effects of an IO in jection of 2 percent lidocaine with 1:100,000 epinephrine and 3 percent mep ivacaine. Methods. With the use of a repeated-measures design, the authors randomly a ssigned 42 subjects to receive IO injections of 1.8 milliliters of 2 percen t lidocaine with 1:100,000 epinephrine or 1.8 mi, of 3 percent mepivacaine in a double-blinded manner at two appointments. At each appointment, the au thors monitored electrocardiographic findings, cardiac rate, systolic and d iastolic blood pressure, and mean arterial pressure before, during and afte r administration of anesthetic solutions. Results. With the 2 percent lidocaine with 1:100,000 epinephrine solution, 28 (67 percent) of 42 subjects experienced an increase in heart rate that m ight be attributed to the effect of the epinephrine. In 22 (79 percent) of these subjects, the heart rate returned to within 5 beats of base-line valu es within four minutes after solution deposition. The authors found no sign ificant increase in heart rate in subjects receiving the 3 percent mepivaca ine. No significant differences (P > .05) were found in mean-diastolic, mea n systolic or mean arterial blood pressure values between the subjects rece iving 2 percent lidocaine with 1:100,000 epinephrine and those receiving 3 percent mepivacaine. Conclusions, The majority of subjects receiving the IO injection of the 2 p ercent lidocaine-epinephrine solution experienced a transient increase in h eart rate. No significant increase in heart rate was seen with the IO injec tion of 3 percent mepivacaine. Clinical implications. While patients would likely notice the heart rate in crease with the lidocaine-epinephrine solution, it would not be clinically significant in most healthy patients. In patients whose medical condition, drug therapies or epinephrine sensitivity suggests caution, 3 percent mepiv acaine is a good alternative for IO injections.