Postoperative Cognitive Dysfunction In Elderly Patients After Urologic Part 1

Postoperative Cognitive Dysfunction In Elderly Patients After Urologic Part 1

ABSTRACT:

It is known that elderly patients in particular can develop postoperative cognitive dysfunction (POCD) after major surgery. Together with the increasing population of the elderly all over the world, anesthesiologists will have to face more cases of POCD, which is found to be associated with old age. There is still no ideal anesthesia method in terms of postoperative cognitive functions in elderly patients and anesthetic recovery parameters. This study aims to compare the effects of balanced inhalation anesthesia and total intravenous anesthesia (TIVA) methods to be applied to patients over 60 who will undergo elective urological surgery on the postoperative recovery and early cognitive functions.

Forty ASA I-III patients aged over 60 years were included in the study. Patients without known neurological diseases, history of psychoactive drug use and alcohol or drug addiction were separated into two groups as inhalation anesthesia (Group I; n=20), and TIVA (Group T; n=20). Maintenance of anesthesia after etomidate/remifentanil/rocuronium induction was achieved with sevoflurane/remifentanil in Group I; and after propofol/remifentanil/rocuronium induction, it was achieved with propofol/remifentanil in Group T.

The groups were equal in terms of their demographic, primary hemodynamic and cognitive parameters, anesthesia times and perioperative complications. Cognitive conditions of the cases were evaluated with Mini Mental State Examination Test (MMSET) in preoperative and postoperative 1st, 2nd and 24th hours.

Among the recovery parameters, while eye opening time was longer in Group T, average arterial pressure at the 5th minute and average heart rates at the 5th, 10th and 15th minutes were higher in Group I (p<0,05). In terms of the other recovery parameters and cognitive functions, there was no difference between the groups. After anesthesia, MMSET values did not demonstrate significant changes in both groups.

There was no difference between sevoflurane/remifentanil anesthesia and propofol/remifetanil anesthesia in terms of postoperative recovery and early cognitive functions in urological patients aged over 60 years. Neither of the anesthesia methods affects early cognitive functions.

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Key words: general anesthesia, postoperative cognitive dysfunction, elderly, urological surgery, TIVA

Postoperative Cognitive Dysfunction In Elderly Patients After Urologic Part 1

INTRODUCTION:

Today, anaesthesiologists more frequently encounter elderly patients on operating tables. Physiological changes that appear in old age make anesthesia application specifical for these patients.1 Changes in central nervous system that begin to appear with old age affect cognitive functions, as well.2 Surgery and anesthesia applications in elderly patients create permanent and temporary effects on cognitive functions.3  During recovery from anesthesia, elderly patients are expected to recover their cognitive functions and these functions are expected to be as clear as they were before anesthesia.4

This study aims to compare effects of balanced inhalation anesthesia (BIA) and total intravenous anesthesia (TIVA) on early recovery and cognitive functions in urologic surgery patients aged over 60 years.

MATERIAL and METHOD:

After obtaining the Hospital Ethics Committee’s approval, this study was applied to 40 ASA I-II-III patients aged over 60 years for whom elective urological surgery is planned due to various diagnoses in the operating room of Vakıf Gureba Training and Research Hospital.

The criteria for excluding from the study was set as rejecting to participate in the study, ASA IV physical condition, having a known allergy to any one of the drugs used in the study, being under 60 years old, history of diagnosed dementia and alzheimer or psychiatric disease, history of using any psychoactive drug use, history of alcohol and substance addiction, history of liver and kidney insufficiency, history of undergoing an operation within the last one year, history of undergoing cardiopulmonary bypass, suspicion from predictable difficult intubation, not being able to comprehend/speak, having hearing, visual or speech handicap.

Patients whose statuses do not constitute a hindrance to the surgery in the routine preoperative examinations were randomly separated into two groups of 20 patients each as TIVA Group (Group T) and BIA Group (Group I) after obtaining their informed consent for participation. All patients were evaluated through Mini-Mental State Examination Test (MMSET) (Figure 1) one night before the surgery.5 Before applying this test, the patients were inquired for their educational status and, if deemed necessary, evaluated through Mini Mental State Examination Test for the Untutored (MMSETU) (Figure 2).6 Those educated at elementary school level or above were considered as “educated” and those who were educated at a lower level or not educated at all were considered as “uneducated”. The patients were informed that the same test would also be applied after surgery.

The patients were taken to the operating room without receiving any premedication; and peripheral O2 saturation (SpO2), electrocardiography (ECG) on DII derivation, noninvasive systolic, diastolic and mean arterial pressures (MAP) were monitored with Dräger Infinity Delta, USA, 2006. The first values were recorded as control values. A peripheral vascular access was established on the dorsum of the non-dominant hand by using an 18 gauge angiocath and 5ml.kg-1 balanced electrolyte solution was infused.

Propofol 1-1.5 mg.kg-1, remifentanil 1µg.kg-1 (3 minutes loading dose) were used in anesthesia induction to patients in Group T. After loss of eyelash reflex, muscle relaxation was achieved with 0.5-0.6 mg.kg-1 rocuronium bromide. For maintenance of anesthesia propofol 0.05-0.1 mg.kg-1.dk-1 and remifentanil 0.15-0.3 µg.kg-1.dk-1 infusion was used. Etomidate 0.2-0.3 mg.kg-1, and remifentanil 1µg.kg-1 /3 minutes loading dose) were used in anesthesia induction to patients in Group I. After loss of eyelash reflex, muscle relaxation was achieved with 0.5-0.6 mg.kg-1 rocuronium bromide. For maintenance of anesthesia 0.8-2.5% sevoflurane was used. All patients received 3 minutes of preoxygenation before anesthesia induction. After intubation, the patients were mechanically ventilated in volume control mode with 3 liter/minute flow and 50% O2– 50% air mixture (Dräger Primus SW 2.n Germany). When necessary, an additional dose of (0.3 mg.kg-1) rocuronium bromide was applied for muscle relaxation. The patients were ventilated during surgery maintaining normocarbic state (ETCO2=32-35mmHg), and MAP was maintained on ±20% level. Depth of anesthesia was tracked with hemodynamic parameters. Despite supeficialization of anesthesia, when MAP decreased by more than 20%, 5 mg ephedrine was applied and when the heart pulse rate (HPR) decreased below 50/min, 0.5 mg atropine was intravenously (IV) applied.

At the end of the surgery, anesthesia was ended. Anesthesia period, surgery period and the time when anesthesia was ceased were noted. When tidal volumes of patients exceeded 4 ml.kg-1 in spontaneous ventilation, extubation was performed. All patients received 0.01 mg.kg-1 atropine and 0.02 mg.kg-1 neostigmine in order to antagonize the effect of myorelaxant. After the anesthesia was ceased, beginning time for spontaneous ventilation, extubation time, spontaneous eye opening time and orientation time when the patients could tell his name and/or city of birth and/or age were recorded. Peri/postoperative complications such as nausea, vomiting, shaking, hypotension, bradycardia, desaturation, bronchospasm, respiratory insufficiency, agitation, use of atropine and dose, use of ephedrine and doses, if applied blood transfusion and amount were recorded for the patients.

All evaluations including MMSETs were conducted by a single anesthesiologist who is unaware of the treatment groups and anesthesia methods. Before the end of surgery, 20 mg tenoxicam IV was applied to the patients for postoperative analgesia purposes. MMSET was applied to the patients again in the 1st, 2nd and 24th hours.

The obtained data were evaluated by using the statistical package program SPSS® PASW Statistics 15.0. Qualitative parameters were defined as % standard deviation and quantitative parameters were defined as mean ± standard deviation. When comparing the two groups, Student’s T, chi square, Mann Whitney U, Kruskal Wallis tests were used. For determining the relation of operational parameters to cognitive functions, correlation; and for analysis of intra-group changes in cognitive functions, ANOVA variance, Wilcoxon respective tests and Friedman test analyses were applied. The obtained p values were accepted as insignificant if >0.05, and as significant if <0.05.

RESULTS:

Age, sex, BMI (body-mass index=kg/m2), educational status, baseline MMSET (MMSET0), MAP, heart rate (HR) values of the cases are demonstrated in Table 1. While Group I consisted of 6 uneducated (30%), 3 literate (15%), 9 elementary school graduate (45%), 2 secondary school graduate (10%) patients; Group T consisted of 2 uneducated (10%), 5 literate (25%), 12 elementary school graduate (60%) and 1 high school graduate (5%) patients. There were no significant differences between the groups in terms of age, sex, BMI, educational status and MMSET0 values (p>0.05). The cases were also examined for their ASA physical conditions. In Group I, there were 7 ASA I (35%), 13 ASA II (65%) and no ASA III patients. In Group T, there were 8 ASA I (40%), 11 ASA II (55%) and 1 ASA III (5%) patients. The distribution of diseases, surgery types (endoscopic/open), anesthesia times and surgery times of the patients were also demonstrated in the Table 1. The groups were equal in terms of surgery type, anesthesia and surgery times (p>0.05).

Recovery periods and rates of groups were evaluated together with beginning time of spontaneous ventilation after ceasing the anesthesia, extubation time, spontaneous eye opening time and the time when of the patient could tell his name. The rate of reaching the evaluated recovery parameters was accepted as the indicator of recovery quality and rate. Recovery parameters of cases were demonstrated in Table 2. Although recovery periods were longer in Group T, there was no difference between groups in terms of beginning time of spontaneous ventilation after ceasing the anesthesia, extubation time, and the time when of the patient could tell his name and/or city of birth and/or age. The spontaneous eye opening time was significantly longer in Group T as compared to Group I (p<0,01).

Postoperative cognitive functions of the cases were evaluated through MMSET applied in the 1st, 2nd and 24th hours. MMSET values of Group I and Group T were demonstrated in Figure 3. Although the MMSET value in the 1st hour was relatively higher in Group I; and the MMSET values in the 2nd and 24th hours were relatively higher in Group T; there was no significant difference between the groups in terms of the MMSET values in the 1st, 2nd and 24th hours (p>0,05).

When the groups were evaluated within themselves, there was no significant relation between MMSET and educational level, ASA physical condition, surgery type. In addition, there was no relation between MMSET and complications such as perioperative nausea and vomiting, shaking, hypotension and bradycardia, either.

There was also no relation between surgery and anesthesia time and MMSET1, MMSET2 and MMSET24 values. However, there was a highly strong relation between MMSET values, when there were evaluated within themselves (Spearman’s r value > 0.75).

The groups were also compared within themselves in terms of preoperative and postoperative MMSET values. The result of the comparison applied with Friedman Test in Group I did not demonstrate any difference between preoperative and postoperative MMSET values. MMSET values in Group T were compared with Wicoxon respective tests; and there was a significant difference between MMSET1 and MMSET2, and MMSET1 and MMSET24 values. It was detected that this difference resulted from the fact that MMSET1 value was lower as compared to the others (MMSET1-MMSET2: p=0.046, MMSET1-MMSET24: p=0.012)

By Padraic D. McCahill, M.D.On: May 03, 2019 at 15:01:51