Long-term effects of anaesthesia: What happens in the body after the procedure
Long-term effects of anaesthesia include neurological and cognitive impairments following general anaesthesia, particularly post-operative delirium and cognitive dysfunction.
Long-term effects of anaesthesia:
Long-term effects of anaesthesia are neurological and cognitive impairments that persist beyond the immediate post-anaesthesia recovery period following general anaesthesia. These primarily include post-operative delirium and post-operative cognitive dysfunction, and particularly affect older patients or those with pre-existing conditions.
Table of Contents
Important note
This article is for information purposes only and is not a substitute for a medical diagnosis or advice. If you are unsure, or if you require a personalised treatment plan, it is essential that you consult a qualified specialist.
Anyone planning an operation under general anaesthesia often wonders what effects the anaesthesia might have beyond the procedure itself. Many people experience nausea and dizziness in the first few hours after waking up, but some patients suffer from symptoms that last for weeks or months. Research in recent years has shown that the brain reacts more sensitively to anaesthetics than had long been assumed.
How anaesthesia leads to long-term effects
Key points at a glance:
- Anaesthetics block electrical signals between nerve cells in the brain
- A drop in blood pressure during surgery reduces cerebral perfusion
- Prolonged anaesthesia causes structural changes to synaptic connections
- Most of the effects are reversible, but they can last for months
Long-term effects of anaesthesia arise from the interaction of several biological mechanisms. Anaesthetics block ion channels in nerve cells, thereby interrupting the transmission of electrical signals in the brain during the procedure. This state is intentional — it is what makes pain-free surgery possible in the first place. The extent to which the brain recovers afterwards depends on various factors.
Mechanism 1: Inhibition of nerve signals
Anaesthetics such as propofol or volatile gases (e.g. sevoflurane) specifically interrupt the transmission of signals between nerve cells. As a result, the brain enters a state of reduced electrical activity. Once the effects of the drugs have worn off, the neural network gradually reactivates. In some patients, this process takes considerably longer than in others.
Mechanism 2: Fall in blood pressure and cerebral perfusion
Blood pressure may drop during anaesthesia. If blood flow to the brain falls below a critical threshold, the oxygen supply to certain regions of the brain is temporarily restricted. According to an expert interview conducted by Charité Berlin, this effect is a key cause of post-operative delirium. Anaesthetists therefore monitor circulation closely throughout the entire procedure.
Mechanism 3: Synaptic changes caused by prolonged anaesthesia
Researchers at Columbia University and the University of Bonn have used two-photon microscopy on the living brain to show that prolonged anaesthesia can alter the structure of synaptic connections. The study was published in the journal PNAS. Lead author Dr Michael Wenzel emphasised that survivors of prolonged intensive care anaesthesia may be at risk of long-term impairments such as confusion or memory loss. These findings relate to long-term sedation, not to short, routine anaesthesia.
According to the prospective Maastricht Aging Study (MAAS), which followed 1,823 cognitively healthy participants aged between 25 and 84 over a period of twelve years (Pennings et al. 2025), a significant negative association between cumulative anaesthesia duration and cognitive decline was observed in three out of four cognitive domains. Verbal memory was not significantly affected.
Post-operative delirium and POCD: the two main forms of long-term effects of anaesthesia
Key points at a glance:
- Post-operative delirium (POD): acute confusion in the first few days following surgery
- Post-operative cognitive dysfunction (POCD): gradual decline over weeks or months
- Both forms are classified as perioperative neurocognitive disorders (PND)
- According to the Yellow List, PND occurs in 11.7 to 63 % of patients following surgical procedures
Post-operative delirium (POD): Confusion as the most common acute complication
Post-operative delirium is an acute disturbance of consciousness that typically occurs within the first 72 hours following an operation. Those affected appear disoriented, fail to recognise their relatives and sleep during the day, whilst being restless at night. Some experience hallucinations or become aggressive. Delirium is considered a medical emergency because it delays recovery and increases the risk of permanent cognitive impairment.
Comparison of post-operative delirium and post-operative cognitive dysfunction by time course and clinical characteristics. As at July 2026.
Particularly alarming: according to Charité Berlin, up to 84 % of all cases of delirium go undiagnosed because the symptoms are misinterpreted as normal post-operative tiredness. Among ventilated intensive care patients, the incidence is even higher. The Nu-DESC questionnaire (Nursing Delirium Screening Scale) is a standardised tool for early detection, but is not yet in widespread use.
Post-operative cognitive dysfunction (POCD): when memory function declines
Post-operative cognitive dysfunction, or POCD for short, refers to a gradual impairment of mental functions that only becomes apparent days or weeks after the operation. Typical symptoms include difficulty finding the right words, slowed thinking, poor concentration and forgetfulness. Those affected describe the feeling of no longer being quite themselves.
The MAAS study assessed four cognitive domains: processing speed, executive functions, memory and visuospatial abilities. In three of these domains, the duration of anaesthesia was a significant predictor of subsequent cognitive performance. POCD occurs in cosmetic surgery for the same reason as in other surgical procedures: the brain reacts to anaesthetics regardless of the reason for the procedure.
Reversible or permanent? Prognosis for the long-term effects of anaesthesia
The long-term effects of anaesthesia can be divided into reversible and potentially permanent outcomes. This distinction is crucial for assessing an individual’s risk.
Reversible consequences
Post-operative delirium (subsides); POCD in young, healthy patients; difficulty concentrating following a short period of anaesthesia; difficulty finding the right words in the first few weeks.
Increased risk of long-term effects
POCD in patients over 65 years of age; multiple or very prolonged periods of anaesthesia; pre-existing dementia or MCI; severe delirium left untreated.
Permanent, severe brain damage following a single routine anaesthetic in otherwise healthy adults is considered rare. The MAAS study demonstrated a statistical association between cumulative anaesthesia duration and cognitive decline — but provided no evidence of irreversible damage following a standard procedure. Risks increase with the number and duration of anaesthetic procedures, not as a result of a single procedure.
Who is particularly at risk? Risk factors for long-term effects of anaesthesia
An individual’s risk of long-term effects of anaesthesia depends on several measurable factors. The following table shows which groups of patients should be particularly vigilant:
| Risk factor | Impact on long-term consequences | Evidence |
|---|---|---|
| Aged 65 or over | Significantly increased risk of delirium and POCD | MAAS study, Charité Berlin |
| High blood pressure, diabetes, heart disease | Exacerbate cognitive decline through reduced cerebral perfusion | MAAS study (Pennings et al. 2025) |
| Prolonged or cumulative duration of anaesthesia | Dose-dependent effect on three out of four cognitive domains | MAAS cohort, n = 1,823 |
| Pre-existing cognitive impairments (MCI, early-stage dementia) | Increased susceptibility to post-operative delirium | ISPOCD1 study, The Lancet |
| Low level of education | Lower cognitive reserve, greater relative decline | MAAS covariate analysis |
| General anaesthesia versus regional anaesthesia | General anaesthesia is associated with a higher risk of delirium | SSAPM guidelines, interview with Charité experts |
Age is the most important single factor. Anyone who also suffers from high blood pressure or diabetes is at an even greater risk, as these conditions already put a strain on the blood supply to the brain.
General anaesthesia carries a higher risk of long-term effects than regional anaesthesia, in which only a limited area of the body is numbed and the patient remains conscious. For some procedures, it is possible to choose between the two methods — the pre-operative consultation with the anaesthetist is the right time to discuss this option.
What patients can do before anaesthesia
Key points at a glance:
- Pre-operative consultation with the anaesthetist: be open about any risk factors
- An anaesthetic depth monitor (BIS) reduces the risk of the anaesthesia being too deep
- Circulatory monitoring prevents critical drops in blood pressure
- Please provide a full list of medicines, including dietary supplements
Long-term effects of anaesthesia cannot be completely ruled out, but the risk of these can be significantly reduced by taking specific measures before the procedure. Experience shows that many patients underestimate the extent to which the pre-operative consultation influences the outcome.
- Make active use of the information session and preliminary discussion Discuss your personal risk profile with the anaesthetist: any pre-existing conditions, regular medication and previous reactions to anaesthesia are important pieces of information. The better the team knows your profile, the more precisely the anaesthesia can be tailored to your needs.
- Request a depth of anaesthesia monitor (BIS) The bispectral index (BIS) monitor continuously measures brain activity and helps ensure that the anaesthesia is neither too deep nor too shallow. Anaesthesia that is too deep increases the risk of delirium. Ask specifically whether BIS monitoring will be used during your procedure.
- Stabilise circulation Critical drops in blood pressure during anaesthesia are a preventable risk factor. Patients with high blood pressure should take their medication as usual — after consulting their doctor — and actively ask for their circulation to be monitored.
- Reducing alcohol and nicotine consumption Both substances affect tolerance to anaesthesia and post-operative recovery. Reducing their intake in the days leading up to the procedure measurably improves the patient’s condition.
What patients can do after anaesthesia
Key points at a glance:
- Early mobilisation after surgery promotes cognitive recovery
- A regular daily routine and social contact help to stabilise the brain
- If you experience persistent confusion or memory lapses, seek medical advice immediately
- Arrange for a trusted person to be present as a support person during the first 24 hours
Post-operative care following anaesthesia is just as important as the preparation. Early mobilisation is the most effective single factor here: being bedridden after an operation increases the risk of delirium. Getting up and moving around soon after the procedure helps to support cognitive recovery.
The Charité recommends that relatives visit regularly and help patients maintain a sense of normality in their daily lives — this measurably reduces the risk of delirium in hospital settings.
If persistent confusion, memory lapses or mood swings occur following the procedure, medical assistance should be sought immediately. Post-operative delirium, when detected early, is much easier to treat than a case that has been overlooked.
Restriction:
Even with optimal preventive measures, anaesthesia can have long-term effects. Particularly in the case of cosmetic procedures that are privately funded, the patient bears the financial risk of any follow-up treatment themselves — statutory health insurance does not cover these costs.
Anaesthetic complications following cosmetic surgery: financial protection
The long-term effects of anaesthesia following cosmetic surgery pose a particular challenge for patients: As cosmetic procedures such as liposuction, rhinoplasty or eyelid lifts are privately funded, statutory health insurance often does not cover, or only partially covers, any resulting costs — even in the case of medically necessary follow-up treatment.
In practical terms, this means that if a patient experiences post-operative delirium following a cosmetic procedure that requires hospitalisation, or if they develop POCD requiring treatment, the costs involved can be substantial. Furthermore, in certain cases, statutory health insurance funds may reclaim the costs of emergency treatment already provided if the cause lies in a privately funded procedure.
Follow-up care insurance fills this gap. It covers medically necessary follow-up treatment arising from an insured procedure — regardless of whether the complication is anaesthetological or surgical in nature. You can find out more about the services covered and frequently asked questions in the 4beauty FAQs.
Financial protection against long-term effects of anaesthesia following cosmetic procedures
4beauty’s follow-up treatment insurance covers medically necessary follow-up treatment resulting from the insured cosmetic procedure — up to 300,000 euros. The insurance can be taken out online up to 24 hours before the procedure.
Frequently asked questions about the long-term effects of anaesthesia
Post-operative delirium, provided it is recognised and treated, subsides within a few days. Post-operative cognitive dysfunction (POCD) can persist for weeks or even several months. In a small proportion of older patients with risk factors, the impairment persists for longer than three months. In healthy patients with no pre-existing conditions, a full recovery is to be expected.
Permanent, severe brain damage following a single anaesthetic is considered rare in healthy adults. The risk increases with cumulative anaesthesia duration, the patient’s age and the presence of comorbidities. The MAAS study (twelve years of follow-up, 1,823 participants) showed a statistical association between duration of anaesthesia and cognitive decline, but found no evidence of irreversible damage following a routine procedure in otherwise healthy patients.
Post-operative delirium (POD) is an acute disturbance of consciousness characterised by disorientation and confusion, which typically occurs within the first 72 hours following surgery and is considered a medical emergency. Post-operative cognitive dysfunction (POCD), on the other hand, manifests gradually as a decline in memory and concentration over a period of weeks to months. Both are classified as perioperative neurocognitive disorders (PND), but differ in terms of onset, duration, treatment and severity.
Older patients aged over 65 are the group most at risk, particularly if they also suffer from high blood pressure, diabetes or heart disease. Patients with pre-existing cognitive impairments — such as mild cognitive impairment (MCI) — are also at increased risk. The cumulative duration of anaesthesia across multiple procedures is another measurable risk factor which, according to the MAAS study, accelerates cognitive decline.
If complications arise following a cosmetic procedure — including anaesthesia-related complications such as delirium or cognitive impairment that require further medical treatment — statutory health insurance often does not cover these costs. Follow-up care insurance covers medically necessary follow-up treatment arising from the insured procedure. Information on the insured benefits can be found in the 4beauty FAQs.
Myth
General anaesthesia always causes permanent brain damage.
Fact
Most cognitive impairments following anaesthesia are temporary and resolve within a matter of weeks or months. Permanent damage only occurs in certain high-risk groups and under unfavourable conditions.
Source: MAAS study (Pennings et al., 2025); Charité Berlin
Myth
Post-operative delirium and cognitive dysfunction are one and the same.
Fact
Post-operative delirium (POD) occurs acutely in the first few days and is a medical emergency characterised by confusion and hallucinations. Post-operative cognitive dysfunction (POCD) develops more slowly and affects memory over a period of weeks to months.
Source: Perioperative Neurocognitive Disorders (PND), S3 guidelines
Myth
Young, healthy patients are completely protected from the long-term effects of anaesthesia.
Fact
Although the risk is significantly lower in younger, healthy patients, they too may develop cognitive impairment following lengthy procedures or if they have certain underlying medical conditions. Age is a risk factor, but not the only one.
Source: MAAS study, 12-year cohort data
Myth
Post-operative delirium is recognised immediately by nursing staff and doctors.
Fact
According to an analysis by Charité Berlin, up to 84 % of all cases of delirium go undiagnosed in everyday clinical practice. Structured screening tools such as the Nu-DESC questionnaire are therefore strongly recommended from a medical perspective.
Source: Charité Berlin, Department of Anaesthesiology and Intensive Care Medicine