Post-Operative Cognitive Dysfunction (POCD)

[BillrothI]

Hey Everybody,

I was speaking with an anesthesiologist recently and he mentioned that he was working on a meta-analysis of POCD studies. I had never heard of the condition before, but found it interesting. I was wondering what your experience has been and what measures you take to reduce incidence among at-risk populations. Has anyone here been involved in any research on the subject? Would love to hear your thoughts, as I'm considering specializing in anesthesiology in the (distant) future and this is something I would like to learn more about.

Thanks,
Bill

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[aneftp]

Usually occurs in older population (age 70 or older). But too many varying factors involved so going to be very hard to isolate cognitive dysfunction since most already have some underlying early stages of memory loss.

If you go back through history, most people who have cognitive dysfunction can experience it upwards to 10 years earlier than when it's actually diagnosed. So if early reports about anesthesia related POCD starts at age 70....that means you really have to document patients from age 60 have POCD. And to this date, I don't find any correlation with those age 60 (in isolated groups) having anesthesia related cognitive dysfunction.

 

[WholeLottaGame7]

Hey Everybody,

I was speaking with an anesthesiologist recently and he mentioned that he was working on a meta-analysis of POCD studies. I had never heard of the condition before, but found it interesting. I was wondering what your experience has been and what measures you take to reduce incidence among at-risk populations. Has anyone here been involved in any research on the subject? Would love to hear your thoughts, as I'm considering specializing in anesthesiology in the (distant) future and this is something I would like to learn more about.

Thanks,
Bill

There's a fair amount of literature out there about it. General vs regional, volatile vs intravenous anesthetics, etc. For example, one of my former co-residents is looking at isoflurane vs propofol, measuring various CSF markers that are associated with cognitive dysfunction.

 

[BLADEMDA]

Anesth Analg. 2011 May;112(5):1179-85. doi: 10.1213/ANE.0b013e318215217e. Epub 2011 Apr 7.
Postoperative cognitive dysfunction is independent of type of surgery and anesthetic.
Evered L1, Scott DA, Silbert B, Maruff P.
Author information

Abstract
BACKGROUND:
Postoperative cognitive dysfunction (POCD) has been documented after cardiac and noncardiac surgery. The type of surgery and anesthetic has been assumed to be associated with the incidence but there are few prospective data comparing the incidence after different procedures. In this study, we sought to determine the association of the type of surgical procedure and anesthesia on the incidence of POCD after procedures involving light sedation, general anesthesia for noncardiac surgery, and general anesthesia for cardiac surgery involving cardiopulmonary bypass.

METHODS:
Eight neuropsychological tests were administered at baseline and at 7 days and 3 months postoperatively to subjects from 3 procedure groups and a nonoperative control group. Reliable change index was used to calculate POCD. The study sample consisted of subjects involved in 3 separate trials investigating coronary angiography (CA) (percutaneous diagnostic procedure) under sedation, major noncardiac surgery (total hip joint replacement [THJR] surgery) under general anesthesia, and coronary artery bypass graft (CABG) surgery under general anesthesia.

RESULTS:
Data were collected from 644 patients in the patient groups and 34 subjects in the control group. Neuropsychological results were available for POCD at day 7 for THJR surgery (n=162) and CABG surgery (n=281). The incidence of POCD at day 7 was 17% for THJR surgery and 43% for CABG surgery (adjusted odds ratio=0.2, 95% confidence interval [CI]: 0.1, 0.4; P<0.01). At 3 months, the incidence of POCD for all groups combined (n=636) was 17% (21% for CA under sedation, 16% for THJR surgery, and 16% for CABG surgery). The mean (95% CI) for the difference in proportions of POCD among groups was 0.00 (-0.07, 0.07) (P=0.91) for CABG versus THJR; -0.05 (-0.12, 0.03) (P=0.21) for CABG versus CA; and -0.05 (-0.13, 0.03) (P=0.24) for THJR versus CA. There were no significant differences among groups (adjusted odds ratio=1.21, 95% CI: 0.94, 1.55; P=0.13).

CONCLUSIONS:
The incidence of POCD in old and elderly patients at day 7 was higher after CABG surgery than THJR surgery, but POCD at 3 months was independent of the nature or the type of procedure or anesthetic when comparing CA, THJR, and CABG surgery groups. Cardiovascular risk factors were not predictive of POCD after any procedure.

 

[BLADEMDA]

IMHO, POCD may, and I stress may, be able to be diminished by avoiding a deep anesthetic; this means keeping the patient light under Local/Regional/Block, etc and/or using Bispectral Index Monitoring.

Again, my opinion is based on a just a few studies which need confirmation utilizing a larger number of patients. That said, if it was a friend or family member with any signs of memory loss or over age 75 I would strongly advise a Local or Regional anesthetic with light sedation only. If General Anesthesia was required to do the surgery I would recommend the use of a BIS and keeping the BIS number between 40-60.

 

[BLADEMDA]

Neurosurg Anesthesiol. 2013 Jan;25(1):33-42. doi: 10.1097/ANA.0b013e3182712fba.
BIS-guided anesthesia decreases postoperative delirium and cognitive decline.
Chan MT1, Cheng BC, Lee TM, Gin T; CODA Trial Group.
Collaborators (16)

Author information

Abstract
BACKGROUND:
Previous clinical trials and animal experiments have suggested that long-lasting neurotoxicity of general anesthetics may lead to postoperative cognitive dysfunction (POCD). Brain function monitoring such as the bispectral index (BIS) facilitates anesthetic titration and has been shown to reduce anesthetic exposure. In a randomized controlled trial, we tested the effect of BIS monitoring on POCD in 921 elderly patients undergoing major noncardiac surgery.

METHODS:
Patients were randomly assigned to receive either BIS-guided anesthesia or routine care. The BIS group had anesthesia adjusted to maintain a BIS value between 40 and 60 during maintenance of anesthesia. Routine care group had BIS measured but not revealed to attending anesthesiologists. Anesthesia was adjusted according to traditional clinical signs and hemodynamic parameters. A neuropsychology battery of tests was administered before and at 1 week and 3 months after surgery. Results were compared with matched control patients who did not have surgery during the same period. Delirium was measured using the confusion assessment method criteria.

RESULTS:
The median (interquartile range) BIS values during the maintenance period of anesthesia were significantly lower in the control group, 36 (31 to 49), compared with the BIS-guided group, 53 (48 to 57), P<0.001. BIS-guided anesthesia reduced propofol delivery by 21% and that for volatile anesthetics by 30%. There were fewer patients with delirium in the BIS group compared with routine care (15.6% vs. 24.1%, P=0.01). Although cognitive performance was similar between groups at 1 week after surgery, patients in the BIS group had a lower rate of POCD at 3 months compared with routine care (10.2% vs. 14.7%; adjusted odds ratio 0.67; 95% confidence interval, 0.32-0.98; P=0.025).

CONCLUSIONS:
BIS-guided anesthesia reduced anesthetic exposure and decreased the risk of POCD at 3 months after surgery. For every 1000 elderly patients undergoing major surgery, anesthetic delivery titrated to a range of BIS between 40 and 60 would prevent 23 patients from POCD and 83 patients from delirium.

 

[BLADEMDA]

Optimised Anaesthesia to Reduce Post Operative Cognitive Decline (POCD) in Older Patients Undergoing Elective Surgery, a Randomised Controlled Trial

Postoperative cognitive decline (POCD) is recognized as a common and impactful outcome of surgical procedures in older adults [1], [2]. POCD is most common after cardiac surgery although up to 40% of people are affected for one week after non-cardiac procedures. Importantly, up to 15% of people continue to be affected after three months [3], [4]. The first major study of long term POCD in people over 60 reported an incidence of 26% one week after surgery and 10% after three months [2]. Whilst the balance of literature supports the persistence of POCD for at least 3 months, not all studies have demonstrated persistent change [5]. A systematic review has highlighted attentional dysfunction as a prominent and sensitive feature of POCD [6]. The clinical significance of POCD, particularly in older indivudals, is emphasised by evidence of the impact it confers on the ability to perform daily activities [7]. Despite the potential long-term implications for patients and health service provision very few studies have assessed POCD for longer than six months post operatively.

[3]. Risk factors include age, preoperative cognitive function, length of the operation, and postoperative respiratory complications and infection. Proposed interventions to modify these factors include monitoring of cerebral oxygen de-saturation (rSO2) and correcting for duration and depth of anaesthesia [8]–[10]. Significant cerebral oxygen desaturation occurs in up to 30% of patients during major non-cardiac surgery and preliminary evidence indicates that monitoring improves outcome by enabling prompt intervention [8], [11]. Measurement of the bispectral index (BIS, Covidien inc, Co, USA) has been promoted as a variable for depth of anaesthesia. There is high correlation between BIS and clinical criteria of sedation, and a recent review reported that BIS-guided anaesthesia improves outcomes of surgical procedures [12]. It will also be important to identify biomarkers which robustly predict the extent and persistence of POCD. The protein S100B has been identified as a predictor of poor outcome following traumatic brain injury and so is a promising candidate[13], [14].

 

[BLADEMDA]

POCD is a "hot" area of research.

1. Avoid overdosing the patient on the anesthetic (the BIS may help here)
2. Maintain BP and Saturation (avoid microinfarcts)
3. Maintain Cerebral Oxygen Saturation (Cerebral Oximetry may help here)

Finally, Why not avoid the General Anesthetic altogether if possible?

 

[BLADEMDA]

Optimised Anaesthesia to Reduce Post Operative Cognitive Decline (POCD) in Older Patients Undergoing Elective Surgery, a Randomised Controlled Trial

Postoperative cognitive decline (POCD) is recognized as a common and impactful outcome of surgical procedures in older adults [1], [2]. POCD is most common after cardiac surgery although up to 40% of people are affected for one week after non-cardiac procedures. Importantly, up to 15% of people continue to be affected after three months [3], [4]. The first major study of long term POCD in people over 60 reported an incidence of 26% one week after surgery and 10% after three months [2]. Whilst the balance of literature supports the persistence of POCD for at least 3 months, not all studies have demonstrated persistent change [5]. A systematic review has highlighted attentional dysfunction as a prominent and sensitive feature of POCD [6]. The clinical significance of POCD, particularly in older indivudals, is emphasised by evidence of the impact it confers on the ability to perform daily activities [7]. Despite the potential long-term implications for patients and health service provision very few studies have assessed POCD for longer than six months post operatively.

[3]. Risk factors include age, preoperative cognitive function, length of the operation, and postoperative respiratory complications and infection. Proposed interventions to modify these factors include monitoring of cerebral oxygen de-saturation (rSO2) and correcting for duration and depth of anaesthesia [8]–[10]. Significant cerebral oxygen desaturation occurs in up to 30% of patients during major non-cardiac surgery and preliminary evidence indicates that monitoring improves outcome by enabling prompt intervention [8], [11]. Measurement of the bispectral index (BIS, Covidien inc, Co, USA) has been promoted as a variable for depth of anaesthesia. There is high correlation between BIS and clinical criteria of sedation, and a recent review reported that BIS-guided anaesthesia improves outcomes of surgical procedures [12]. It will also be important to identify biomarkers which robustly predict the extent and persistence of POCD. The protein S100B has been identified as a predictor of poor outcome following traumatic brain injury and so is a promising candidate[13], [14].

The study highlights significant and persistent cognitive deficits in older people after major-non cardiac surgery. A preliminary RCT suggests that a pragmatic intervention focussing upon BIS and rSO2 can significantly reduce cognitive impairment at one, 12 and 52 weeks post-operatively.


http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037410

 

[BLADEMDA]

CONCLUSION: The use of light propofol sedation decreased the prevalence of postoperative delirium by 50% compared with deep sedation. Limiting depth of sedation during spinal anesthesia is a simple, safe, and cost-effective intervention for preventing postoperative delirium in elderly patients that could be widely and readily adopted.


http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2800291/

 

[BLADEMDA]

Anesth Analg. 2014 May;118(5):977-80. doi: 10.1213/ANE.0000000000000157.
Sedation depth during spinal anesthesia and survival in elderly patients undergoing hip fracture repair.
Brown CH 4th1, Azman AS, Gottschalk A, Mears SC, Sieber FE.
Author information

Abstract
Low intraoperative Bispectral Index (BIS) values may be associated with increased mortality. In a previously reported trial to prevent delirium, we randomized patients undergoing hip fracture repair under spinal anesthesia to light (BIS >80) or deep (BIS approximately 50) sedation. We analyzed survival of patients in the original trial. Among all patients, mortality was equivalent across sedation groups. However, among patients with serious comorbidities (Charlson score >4), 1-year mortality was reduced in the light (22.2%) vs deep (43.6%) sedation group (hazard ratio

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, 0.43; 95% confidence interval, 0.19-0.97; P = 0.04) during spinal anesthesia. Similarly, among patients with Charlson score >6, 1-year mortality was reduced in the light (28.6%) vs deep (52.6%) sedation group (HR 0.33; 95% confidence interval, 0.12-0.94; P = 0.04) during spinal anesthesia. Further research on reduced mortality after light sedation during spinal anesthesia is needed

 

[BuzzPhreed]

Not this again...

1) Patient invariably has subclinical cognitive impairment pre-operatively.
2) Most return to baseline within 3 months.
3) Stress of surgery and peri-operative milieu are more relevant than choice of anesthetic.

This was covered heavily and in-depth at the last ASA meeting in October 2013. The BIS is nothing more than an answer looking for a problem. And it is a tool only for hacks and CRNAs.

 

[Arch Guillotti]

And it is a tool only for hacks and CRNAs.

QFT.

 

[BillrothI]

Thanks for sharing, @BLADEMDA!

BIS-guided anesthesia is not routine, correct?

I am wondering why a small but significant number of younger patients suffer from POCD. Several studies have concluded that only the elderly are at significant risk for POCD, but from what I've read ~5% of patients 18-49 also suffer lasting cognitive dysfunction following surgery. Is this not a cause for concern? It is conceivable that elderly patients may be suffering from subclinical cognitive impairment pre-operatively, as @BuzzPhreed pointed out, or are simply more susceptible to whatever underlying mechanisms trigger POCD. However, it is not unheard of among young and middle-aged patients. Do you have any ideas why this might be the case? If you were to undergo cardiac surgery, what interventions would you ask your trusted colleague to put in place?

Thanks again.

-Bill

 

[kmurp]

My understanding is that POCD may be distinct from acute postoperative delirium. That latter (I think) is what we see in younger patients, though, of course, we see it in the elderly as well. Hip fracures seem to be the worst.

 

[BLADEMDA]

Thanks for sharing, @BLADEMDA!

BIS-guided anesthesia is not routine, correct?

I am wondering why a small but significant number of younger patients suffer from POCD. Several studies have concluded that only the elderly are at significant risk for POCD, but from what I've read ~5% of patients 18-49 also suffer lasting cognitive dysfunction following surgery. Is this not a cause for concern? It is conceivable that elderly patients may be suffering from subclinical cognitive impairment pre-operatively, as @BuzzPhreed pointed out, or are simply more susceptible to whatever underlying mechanisms trigger POCD. However, it is not unheard of among young and middle-aged patients. Do you have any ideas why this might be the case? If you were to undergo cardiac surgery, what interventions would you ask your trusted colleague to put in place?

Thanks again.

-Bill

If I was undergoing a CABG at age 70 or 75 I would request a BIS, Cerebral Oximetry and a star surgeon.

The risk of POCD is probably a bit greater going on bypass than an off pump CABG and mental function is better preserved staying off bypass but I'd go with my surgeon's recommendation there.

 

[BLADEMDA]

Thanks for sharing, @BLADEMDA!

BIS-guided anesthesia is not routine, correct?

I am wondering why a small but significant number of younger patients suffer from POCD. Several studies have concluded that only the elderly are at significant risk for POCD, but from what I've read ~5% of patients 18-49 also suffer lasting cognitive dysfunction following surgery. Is this not a cause for concern? It is conceivable that elderly patients may be suffering from subclinical cognitive impairment pre-operatively, as @BuzzPhreed pointed out, or are simply more susceptible to whatever underlying mechanisms trigger POCD. However, it is not unheard of among young and middle-aged patients. Do you have any ideas why this might be the case? If you were to undergo cardiac surgery, what interventions would you ask your trusted colleague to put in place?

Thanks again.

-Bill

It's important not to get postop delirium confused with POCD. (Pun intended there). Younger patients are more likely to get Delirium over POCD. Ill post some studies next.

 

[BLADEMDA]

Anesthesiology. 2002 Jun;96(6):1351-7.
Postoperative cognitive dysfunction in middle-aged patients.
Johnson T1, Monk T, Rasmussen LS, Abildstrom H, Houx P, Korttila K, Kuipers HM, Hanning CD, Siersma VD, Kristensen D, Canet J, Ibañaz MT, Moller JT; ISPOCD2 Investigators.
Author information

Abstract
BACKGROUND:
Postoperative cognitive dysfunction (POCD) after noncardiac surgery is strongly associated with increasing age in elderly patients; middle-aged patients (aged 40-60 yr) may be expected to have a lower incidence, although subjective complaints are frequent.

METHODS:
The authors compared the changes in neuropsychological test results at 1 week and 3 months in patients aged 40-60 yr, using a battery of neuropsychological tests, with those of age-matched control subjects using Z-score analysis. They assessed risk factors and associations of POCD with measures of subjective cognitive function, depression, and activities of daily living.

RESULTS:
At 7 days, cognitive dysfunction as defined was present in 19.2% (confidence interval [CI], 15.7-23.1) of the patients and in 4.0% (CI, 1.6-8.0) of control subjects (P < 0.001). After 3 months, the incidence was 6.2% (CI, 4.1-8.9) in patients and 4.1% (CI, 1.7-8.4) in control subjects (not significant). POCD at 7 days was associated with supplementary epidural analgesia and reported avoidance of alcohol consumption. At 3 months, 29% of patients had subjective symptoms of POCD, and this finding was associated with depression. Early POCD was associated with reports of lower activity scores at 3 months.

CONCLUSIONS:
Postoperative cognitive dysfunction occurs frequently but resolves by 3 months after surgery. It may be associated with decreased activity during this period. Subjective report overestimates the incidence of POCD. Patients may be helped by recognition that the problem is genuine and reassured that it is likely to be transient.

 

[BLADEMDA]

Anesthesiology. 2008 Jan;108(1):18-30.
Predictors of cognitive dysfunction after major noncardiac surgery.
Monk TG1, Weldon BC, Garvan CW, Dede DE, van der Aa MT, Heilman KM, Gravenstein JS.
Author information

Abstract
BACKGROUND:
The authors designed a prospective longitudinal study to investigate the hypothesis that advancing age is a risk factor for postoperative cognitive dysfunction (POCD) after major noncardiac surgery and the impact of POCD on mortality in the first year after surgery.

METHODS:
One thousand sixty-four patients aged 18 yr or older completed neuropsychological tests before surgery, at hospital discharge, and 3 months after surgery. Patients were categorized as young (18-39 yr), middle-aged (40-59 yr), or elderly (60 yr or older). At 1 yr after surgery, patients were contacted to determine their survival status.

RESULTS:
At hospital discharge, POCD was present in 117 (36.6%) young, 112 (30.4%) middle-aged, and 138 (41.4%) elderly patients. There was a significant difference between all age groups and the age-matched control subjects (P < 0.001). At 3 months after surgery, POCD was present in 16 (5.7%) young, 19 (5.6%) middle-aged, and 39 (12.7%) elderly patients. At this time point, the prevalence of cognitive dysfunction was similar between age-matched controls and young and middle-aged patients but significantly higher in elderly patients compared to elderly control subjects (P < 0.001). The independent risk factors for POCD at 3 months after surgery were increasing age, lower educational level, a history of previous cerebral vascular accident with no residual impairment, and POCD at hospital discharge. Patients with POCD at hospital discharge were more likely to die in the first 3 months after surgery (P = 0.02). Likewise, patients who had POCD at both hospital discharge and 3 months after surgery were more likely to die in the first year after surgery (P = 0.02).

CONCLUSIONS:
Cognitive dysfunction is common in adult patients of all ages at hospital discharge after major noncardiac surgery, but only the elderly (aged 60 yr or older) are at significant risk for long-term cognitive problems. Patients with POCD are at an increased risk of death in the first year after surgery.