| JOURNAL HOME | CME HOME | THIS MONTH | PAST ISSUES | ETOC | COLLECTIONS |
| AUTHORS | REVIEWERS | EDITORIAL BOARD | FEEDBACK | RSS | HELP |
| ||||||||||||||
| ||||||||||||||
|
|
|
|
||||||||||||
|
||||||||||||||
*Department of Anesthesiology, Kaplan Medical Center, Rehovot, Israel,
Department of Anesthesiology and Critical Care Medicine, Hadassah University Hospital and The Hebrew University School of Medicine, Jerusalem, Israel
Address correspondence and reprint requests to Yaacov Gozal, MD, Department of Anesthesiology and Critical Care Medicine, Hadassah University Hospital, PO Box 12000, Jerusalem 91120, Israel.
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
20% of baseline), whereas postoperative ischemic changes were mostly independent of heart rate. Only one of the ischemic patients (in the GA group) was admitted as a result of intractable chest pain. There were significantly less intraoperative episodes in the LA group, suggesting that LA may be safer than GA in patients during this type of surgery.
Implications: In patients with risk factors for ischemic heart disease, cataract surgery occurs in 30% of the cases with ischemic events of short duration. There were significantly less intraoperative episodes in the local anesthesia group, suggesting that local anesthesia may be safer than general anesthesia in patients during this type of surgery.
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
We have shown that retinal surgery performed under local anesthesia is accompanied by a frequent incidence of postoperative myocardial ischemia (27%) (5). Cataract surgery is performed under either local or general anesthesia, mostly based on the surgeon’s preference and the patient’s cooperation. Little is known about cardiac ischemia in ophthalmic surgery under general anesthesia, and no prospective study has been performed to compare cardiac morbidity with general and local anesthesia.
This prospective study was designed to compare the incidence of perioperative myocardial ischemia in elderly patients undergoing cataract surgery under general or local anesthesia.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
A 12-lead ECG was recorded before surgery and 24 h postoperatively. Myocardial ischemia was assessed by a two-channel AM Holter recorder (Medilog 4500, Oxford Ltd, UK). Two bipolar leads (modified L2 and V5) were used. The recording started 60 min before anesthesia and continued for 24 h. The patients stayed overnight in the hospital, regardless of the type of anesthesia as is the usual practice, to allow an ophthalmologic examination the next morning. Holter tapes were analyzed by two independent investigators blinded as to patient identity, type of anesthesia, and clinical course.
Ischemia was defined as reversible ST segment changes lasting 1 min and involving a shift from baseline (adjusted for positional changes) of either 0.1 mV ST depression measured 60 ms after the J point, unless that point occurred within the T wave, in which case it was measured 40 ms after the J point, or ST increase 0.2 mV at the J point. The baseline level of the ST segment was defined as its position during a stable period (usually 15–30 min) preceding each episode of change. The reversibility of an ischemic episode was defined by the return of the ST segment to the baseline for 1 min.
Twelve-month postoperative patient contact by telephone was made by an observer who was unaware of the Holter analysis results. Patients or their families were asked about new cardiac events and/or change in cardiac medications.
LA (retrobulbar block) was performed by the ophthalmologist in the operating room under sedation with IV midazolam (1–3 mg) by using a mixture of bupivacaine 0.5% and lidocaine 4% (3 mL each). GA was induced with thiopental, fentanyl, and vecuronium and maintained with nitrous oxide and isoflurane in oxygen. Additional fentanyl was given as needed. After securing the endotracheal tube, a retrobulbar block was performed by the surgeon to decrease anesthetic requirement and to facilitate postoperative analgesia.
Patients in both groups stayed 2 h in the postanesthesia care unit for closer monitoring, including continuous oxygen saturation recording, and noninvasive blood pressure recording (every 5 min). Afterwards, the patients were sent to the ward where these variables were checked once every shift.
Data are presented as mean ± SD. Statistical comparisons were made with Student’s t-test and two-way analysis of variance where appropriate. P values of <0.05 were considered statistically significant.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Demographic data are presented in Table 1. There was no difference between the two groups.
|
Systolic blood pressure has decreased significantly during GA, from 146.1 ± 12 to 102.4 ± 13 mm Hg. In the LA group, however, there was an increase in blood pressure during surgery (from 139.9 ± 11 to 160.0 ± 17 mm Hg).
No myocardial ischemia was recorded before surgery. A frequent incidence of intra- and/or postoperative myocardial ischemia was noted in both groups: in 12 of 39 patients (31%) in the LA group and in 13 of 42 (31%) in the GA group (P = NS). The characteristics of the ischemic events are presented in Tables 2 and 3. In all patients, myocardial ischemia was expressed as an ST depression. Both groups were also similar in the duration of the ischemic events, 18.1 ± 4.9 min in the LA group and 16.1 ± 2.9 min in the GA group, P = NS. The difference between the groups was in the timing of the ischemic events and in their number. In the GA group, the number of ischemic events was significantly increased: 18 vs 13 in the LA group (P < 0.05), and 8 of 13 GA patients, the ischemic events occurred during the operation, compared with only one patient of 12 in the LA group (P < 0.01). All intraoperative events were associated with an increase in heart rate (defined as increase 20% of baseline), whereas the postoperative ischemic changes were independent of changes in heart rate in 10 of 22 patients.
|
|
No contributing factor leading to ischemia was found. No difference in demographic (type of risk factors or current medications) or hemodynamic (heart rate change) variables were demonstrated in patients with and without ischemia.
In a 12-mo follow-up, only 33% of the patients or their families could be reached or were willing to participate. Of the 27 interviewed, 2 patients (1 in the GA group and 1 in the LA group) described a new cardiac event. One of the patients underwent coronary artery bypass grafting surgery as a result of unstable angina 9 mo after the cataract surgery and in the other, cardiac catheterization with balloon angioplasty was performed 8 mo after surgery. No death related to a cardiac event was reported in this 12-mo period. Patients did not report cardiac-originated symptoms in the immediate postoperative home recovery.
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Only a few studies have evaluated the mortality and morbidity associated with ophthalmic surgery (6–8). In a retrospective study, Badrinath et al. (6) concluded that both LA and GA were associated with similar mortality after ophthalmic surgery. However, they did not consider myocardial ischemia as a risk factor for morbidity and mortality. Barker et al. (7) compared postoperative symptoms such as pain, nausea, and vomiting in patients undergoing cataract surgery using either GA or LA. Schein et al. (8), in a prospective, randomized, multicenter study have shown that routine preoperative testing does not reduce the risk of adverse perioperative events in patients undergoing cataract surgery. However, in this study, myocardial ischemia was defined as new or more severe chest pain. It is possible that they missed many of the ischemic events because perioperative myocardial ischemia is virtually always silent. We have shown, in a previous study (5), that retinal surgery with LA was accompanied by a frequent incidence (27%) of postoperative myocardial ischemia. However, perioperative myocardial ischemia related to cataract surgery has not been investigated prospectively. Our present study agrees with our previous one and has also demonstrated a 30% incidence of perioperative myocardial ischemia in patients undergoing cataract surgery under either LA or GA.
Hemodynamic instability associated with GA is alleged to be one of the advantages of using LA. Barker et al. (9) have shown in a study involving 20 elderly cataract patients that heart rate increased significantly after the induction of GA compared with LA. Mean arterial blood pressure increased significantly in both groups after the induction of anesthesia, but decreased to lower than control values in the GA group during the rest of the study, whereas it remained moderately increased (10 mm Hg higher than control values) in the LA group. LA, in the same study, prevented the small increase in epinephrine, norepinephrine secretion, and glucose plasma level seen in the GA group. In addition, the same investigators have demonstrated the absence of excessive release of cortisol in the LA group compared with a significant increase (from 407 nmol/L to 801 nmol/L) in the GA group (10). In surgical patients, the hemodynamic changes strongly associated with myocardial ischemia are tachycardia (11) and relative hypotension (12) leading to an imbalance between myocardial oxygen demand and delivery and to myocardial ischemia. In the present study, eight patients in the GA group and only one in the LA group presented with intraoperative myocardial ischemia. This finding is consistent with our previous study (5), in which no case of intraoperative myocardial ischemia during retinal surgery was observed under LA. In the present study, intraoperative ischemia was invariably found in patients during GA with tachycardia and hypotension. However, patients using LA were hemodynamically stable, except for a few minutes of transient hypertension when the block was performed.
Postoperative ischemia was related to tachycardia in only 54.7% of the patients, approximately nine hours after surgery in both groups. This was probably related to pain resulting from the fading of the ocular block. Late postoperative ischemic episodes were not associated with tachycardia. These events may be explained by an increase in catecholamine levels that results metabolically in increased cholesterol and free fatty acids, and increased platelet aggregation leading to a reduction in myocardial oxygen supply (13).
As described in previous articles (1,5,12), only ST segment depression was present; no case of ST segment increase was recorded. Ischemic episodes were asymptomatic and of short duration, except for one patient in whom proper treatment in the intensive care unit during the "therapeutic window" (12) probably prevented development of a more serious cardiac event.
The major limitations of the study design are the following: 1) a relatively small sample size, which limits the interpretation of the results regarding the effects of GA versus LA on postoperative myocardial ischemia. However, intraoperatively, the difference was statistically significant and may influence an ophthalmologist’s choice of anesthesia; 2) differences in outcome were not noted because it was not an aim of this study (ECGs were not recorded daily in the first week postoperativeley, and cardiac enzymes (creatine phosphokinase-MB, Troponin I) were not checked; and 3) the poor one-year follow-up rate (only 33% of the patients) was obviously not sufficiently reliable. The population studied was a relatively low socioeconomic class and/or an immigrant population. These patients left the country, moved to a different city, or were not willing to give us any information. A much larger-scale prospective, randomized study is warranted to determine whether LA or GA may change the rate of myocardial infarction or cardiovascular death after cataract surgery.
In summary, cataract surgery in elderly patients with risk factors for coronary artery disease or ischemic heart disease is associated with ischemic events of short duration in approximately one-third of patients. These ischemic episodes were frequent during this type of surgery using GA, and occurred equally during the procedure and in the postoperative phase. In patients undergoing the cataract surgery using LA, ischemic episodes occurred mainly in the postoperative period.
|
Footnotes |
|---|
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
This article has been cited by other articles:
|
|
 |
|
  R. MacPherson Structured assessment tool to evaluate patient suitability for cataract surgery under local anaesthesia Br. J. Anaesth., October 1, 2004; 93(4): 521 - 524. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Glantz, T. Ezri, Y. Cohen, S. Konichezky, A. Caspi, D. Geva, and A. Leviav Perioperative Myocardial Ischemia in Patients Undergoing Sternectomy Shortly After Coronary Artery Bypass Grafting Anesth. Analg., June 1, 2003; 96(6): 1566 - 1571. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Jin and F. Chung Minimizing perioperative adverse events in the elderly{dagger} Br. J. Anaesth., October 1, 2001; 87(4): 608 - 624. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Dhingra, Y. Gozal, B. Drenger, and L. Glantz Myocardial Ischemia in Cataract Surgery Patients Anesth. Analg., August 1, 2001; 93(2): 518 - 518. [Full Text] [PDF]
|
|
|
|
 |
|
 T. Y. Wong Regular review: Effect of increasing age on cataract surgery outcomes in very elderly patients BMJ, May 5, 2001; 322(7294): 1104 - 1106. [Full Text]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
