Cardiovascular Risk: RESULTS

In: Anesthesia

15 Mar 2010

The following general data were recorded for the 50 patients in the local anesthetic group. The mean age was 58.3 years, SD ± 11.0. There were 41 male and 9 female subjects. Cardiac pathology was derived from the World Health Organization Index for Cardiac Dis ease. Nine subjects (18%) had valvular heart disease, 14 (28%) had hypertension, 23 (46%) experienced ischemia, 1 (2%) had cardiomyopathy, 1 (2%) had cardiac dysrhythmias, and 2 (4%) had heart failure. The mean quantity of local anesthesia was 4.9 ± 2.0 mL. Hypotensive therapy (($ blockers, calcium channel antagonists, diuretics, vasodilators, and angiotensin-converting enzyme inhibitors) was administered to 22 subjects (44%). The duration of surgery was 15.5 ± 10.4 minutes, and 2 patients (4%) experienced dental pain during surgery.

The same data were collected for the 25 patients in the sedation group. The mean age was 57.7 years, SD ± 13.6. There were 15 male and 10 female subjects. One subject (4%) had rheumatic heart disease, 1 (4%) had valvular problems, 4 (16%) had hypertension, 17 (68%) were ischemic, 1 (4%) had cardiac dysrhythmias, and 1 (4%) had a heart transplant. The mean quantity local anesthesia was 5.5 ±1.4 mL. The mean quantity of sedation was 6.4 ± 1.8 mg. Hypotensive therapy was administered to 16 patients (64%), and the duration of surgery was 20.0 ± 10.4 minutes. One patient (4%) experienced pain.

Figure 1. Heart rate profiles (variation from baseline)

Figure 1. Heart rate profiles (variation from baseline). О in­dicates lidocaine, noradrenaline, and vasopressin; lido-caine, noradrenaline, vasopressin, and midazolam; bars, 95% confidence interval.

For the local anesthetic group, there were statistically significant changes to the individual parameters of mean HR (-2.6%, P < .01) and mean systolic blood pressure (+8.4%, P < .01) with the administration of anesthetic (Table; Figures 1 and 2). Graphically, the results for sys­tolic blood pressure formed a peaked data profile that was time dependent, rising from a baseline value to a peak and then falling. This pattern of response generates interest in the peak, which may be related to the maximum effect of the given agent. However, despite this profile, there were no significant differences between the individual phases of treatment.

For the ECG, a total of 181,765 electrocardiographic wave (QRS) complexes were counted and analyzed, and 1333 (0.73%) proved to be dysrhythmia A total of 43.8% of dysrhythmias occurred during the investigated phases and affected 50.0% of patients in the group:

18.9% during stabilization, 22.4% during local anesthesia, 36.2% during surgery, and 22.4% during recovery. The main dysrhythmias were premature ventricular beats (29.8%), ventricular ectopics (37.5%), and complex ventricular beats (8.3%) and pauses (8.3%). A total of 97.3% were benign, whereas 2.7% were malignant. Statistically, there were no significant differences between the phases of treatment. No patients had significant displacement to the ST segment (diagnosed as a shift equal to or greater than a 1-mm 0.15 mV).

For the sedation group, midazolam induced significant changes to the parameters of HR (+4.1%, P < .01) and systolic (SBP; -17.4%, P < .01). The administration of anesthetic then induced further significant changes in HR (-14.0%, P < .01) and SBP (+19.4%, P < .01). However, there were again no significant differences between the phases of treatment (Table; Figures 1 and 2).

Figure 2. Systolic blood pressure profiles

Figure 2. Systolic blood pressure profiles (variation from baseline). О indicates lidocaine, noradrenaline, and vasopressin; •, lidocaine, noradrenaline, vasopressin, and midazolam; bars, 95% confidence interval.

For the ECG, a total of 88,124 QRS complexes were counted and analyzed; 769 (0.87%) proved to be dysrhythmia A total of 15.9% of dysrhythmias occurred during the investigated phases and affected 52.0% of patients in the group. A total of 23.9% occurred during stabilization: 20.7% during sedation, 21.5% during local anesthesia, 25.2% during surgery, and 8.6% during recovery. The main dysrhythmias were premature ventricular beats (20.0%), ventricular ectopics (32.0%), and complex ventricular beats (8.0%). Of these, 94.3% were benign and 5.7% were malignant. Again, there were no significant differences between the phases of treatment. Three patients (12%) exhibited significant displacement to the ST segment.

There were no significant differences between the anesthetic and sedation groups for HR, but midazolam significantly attenuated SBP (P < .01) for the phases of anesthesia, surgery and recovery. For electrocardiography in the anesthetic group, 33% of the total number of ventricular ectopics (37.5% of benign arrhythmias) and, for the sedation group, 39% of the total number of ventricular ectopics (15.5% of benign arrhythmias), were accounted for by a single individual in each group, which precluded accurate comparison. Malignant arrhythmic activity increased marginally with the use of midazolam, from 2.7 to 5.7%. Dysrhythmic activity for both groups was greatest during the phase of surgery.

However, all these events represented an average effect, and although some members of the trial population might have experienced a greater improvement to outcome, some might not. The extreme responders (the individuals with the greatest change in HR, SBP, or ECG during the phase of local anesthesia) were as follows: in the local anesthetic group, the greatest change

to HR, from 104 to 168 beats per minute (bpm; mean = 123) occurred in a 34-year-old woman with hypertensive heart disease and insulin-dependent diabetes. The local anesthetic volume was 4 mL. She received no hypotensive therapy. We surgically removed a wisdom tooth; the surgery duration was 18 minutes, and she experienced no pain. The greatest change to SBP, from 150 to 194 mm Hg (mean = 173) occurred in a 69-year-old man with hypertensive heart disease, chronic obstructive airways disease, and insulin-dependent diabetes. Local anesthetic volume was 8 mL. He received no hypotensive therapy and underwent surgical exodon-tia for 5 teeth. The surgery duration was 15 minutes, and he experienced no pain. The greatest change to the ECG, 35 ventricular ectopic (VE) beats (7.0% of total VE for the group, rate = 2.4 bpm; other arrhythmias, 1 couplet, 46 premature supraventricular beats, a single pause, and no ST segment deviation; HR, mean = 92.8 bpm, maximal = 97 bpm; SBP, mean = 104 mm Hg, maximal = 111 mm Hg), occurred in a 52-year-old male with valvular heart disease, taking no medication. The local anesthetic volume was 8.5 mL. He underwent dental clearance. The surgery duration was 23 minutes, and he felt no pain. canadian antibiotics

In the sedation group, the greatest change to HR, from 91.2 to 120 bpm (mean =115) occurred in a 4-year-old girl with cardiac dysrhythmia. She took 6 mg midazolam. The local anesthetic volume was 3 mL. She received no hypotensive therapy and underwent an api-coectomy, which lasted 14 minutes. She experienced no pain. The greatest change to SBP, from 129 to 152 mm Hg (mean = 135) occurred in a 57 year-old-man with a heart transplant. He took 8 mg midazolam. The local anesthetic volume was 8 mL. He received no hypotensive therapy and underwent surgical removal of 4 teeth. The procedure lasted 22 minutes, and he experienced no pain. The greatest change to the ECG, 22 VE beats, (4.9% of total VE for the group, rate = 2.2 bpm; other arrhythmias, 2 pauses, no ST segment changes; HR, mean = 55 bpm, maximal = 59 bpm; SBP, mean = 134 mm Hg, maximal = 150 mm Hg), occurred in a 74-year-old male with hypertension and a p-blockade. He took 10 mg midazolam. The local anesthetic volume was 6 mL. He underwent a maxillary sequestrectomy, which lasted 14 minutes, and he felt no pain.

The frequency for successful analgesia with lidocaine, noradrenaline, and vasopressin, defined as surgery without pain, was excellent at 96% for both the anesthetic and sedation groups.


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