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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1739_Библиотеки_им_академика_М_И_Перельмана.pdf
54
A Simple Introduction to Organ Transplant
Dr Gopi Ayyaswamy
Glasgow Coma Scale
Behaviour Response Score
Eye opening
response
E
Spontaneously 4
To speech 3
To pain 2
No response 1
Best verbal response
V
Oriented to time, place and person 5
Confused 4
Inappropriate words 3
Incomprehensible sounds 2
No response 1
Best motor response
M
Obeys commands, moves all limbs 6
Moves to localized pain 5
Flexion withdrawal from pain 4
Abnormal exion (decorticate) 3
Abnormal extension (decerebrate) 2
No response 1
Total score
Best response 15/15
Comatose patient 8 or less
Totally unresponsive 3/15
Brain Stem Death
55
Dr Gopi Ayyaswamy
Consciousness
level
Diagnostic criteria
Brain stem
death
• No arousal/eye-opening
• No behavioural signs of awareness
• Apnoea
• Loss of brain functions (brainstem reexes)
Reference: Medical Consultants on the Diagnosis of Death, 1981
Coma
• No arousal/eye-opening
• No behavioural signs of awareness
• Impaired spontaneous breathing
• Impaired brain stem reexes
• No vocalizations > 1 hour
Reference: Plum & Posner, 1966
Vegetative
state
• Arousal/spontaneous or stimulus-induced eye opening
• No behavioural signs of awareness
• Preserved spontaneous breathing
• Preserved brain stem reexes
• No purposeful behaviours
• No language production of comprehension
• Preservation (partial or complete) of hypothalamic and brain stem autonomic
functions
• > 1 month: Persistent vegetative
• Compatible: Grimaces to pain, localization to sounds
• Atypical but compatible: Visual xation, response to threat, inappropriate
single words
Reference: The Multi-Society Task Force on PVS, 1994 Working Party of the Royal
College of Physicians, 2003
Minimally
conscious
state
• Arousal/spontaneous eye-opening
• Fluctuating but reproducible behavioural signs of awareness
• Response to verbal order
• Environmentally-contingent smiling or crying
• Object localization and manipulation
• Sustained visual xation and pursuit
• Verbalizations
• Intentional but unreliable communication
• Emergence from MCS: functional communication, functional object use
Reference: Giacino et al., 2002
Locked-in
syndrome
• Arousal/spontaneous eye-opening
• Preserved cognitive functions
• Communication vis eye gaze
• Anarthria
• Tetraplegia
Reference: American Congress of Rehabilitation Medicine, 1995
56
A Simple Introduction to Organ Transplant
Dr Gopi Ayyaswamy
professionals can assess the suitability of the organs for transplantation,
match them with potential recipients, and make the necessary arrangements
for the surgical procedure.
Brain death necessitates the use of a ventilator to sustain the functioning
of organs such as the heart, liver, kidneys, and pancreas, which have the
best chances of successful transplantation when they receive a constant
supply of blood and oxygen. The ventilator provides the necessary support
for these organs while facilitating the donation process through careful
coordination and preparation.
Diagnosis of Brain Stem Death
The diagnosis of brain stem death is primarily clinical. No other
tests are required if the full clinical examination, including each of
two assessments of brain stem reexes and a single apnoea test, are
conclusively performed. Diagnostic criteria for brain stem death, coma,
vegetative and minimally conscious states and locked-in syndrome tabled
for clear understanding.
Key Features of Brain Death
• Complete loss of brain function: Brain death denotes the irreversible
loss of all brain functions, including cognition, consciousness, and brain
stem activity.
• Unresponsiveness: Brain-dead patients do not react to external stimuli,
such as pain, light, or verbal commands.
• Reex Absence: Conrmation of brain death relies on the absence
of brain stem reexes like pupillary reactions, eye movements, and
responses to painful stimuli.
• Fixed, dilated pupils: Typically, pupils in brain-dead individuals remain
xed and dilated, failing to constrict in response to light.
• Lack of spontaneous breathing: Brain-dead patients cannot breathe
spontaneously and need mechanical ventilation for oxygen supply.
• Cranial nerve dysfunction: Brain death results in impaired cranial
nerve function, impacting facial movements, the gag reex, and other
brainstem-controlled functions.
Brain Stem Death
57
Dr Gopi Ayyaswamy
• Flat EEG pattern: Electroencephalograms (EEGs) display a flat or
isoelectric pattern, indicating no electrical brain activity in brain-dead
individuals.
• Persistent coma: Brain death typically follows a prolonged, irreversible
coma without recovery prospects.
• Irreversibility: Brain death is irreversible, differing from a coma where
recovery may be possible with appropriate care.
• Legal and ethical signicance: The diagnosis of brain death carries
significant legal and ethical implications, especially in decisions
related to organ donation and end-of-life care, determined by medical
professionals to conrm an individual’s demise.
Dr Gopi Ayyaswamy
Maintenance of Brain
Dead Patients
9
Appropriate support before and after brain stem death can improve the
number and quality of donor organs. Donor management is a continuation
of previous critical care management but with a shift in goals. It should
be delivered in intensive care team by experienced staff.
• Goals of organ donor management
• The principles of donor management
• Monitoring of organ donor
• Standard donor care
Goals of Organ Donor Management
1. Maintain body temperature
2. Adequate oxygenation
3. Adequate circulating volume
4. Cardiovascular stability
5. Adequate urine output.
To follow “Rule of 100”
• Systolic arterial pressure >100 mmHg
• Urine output > 100 ml/hour
• PaO
2
> 100 mmHg
• Hg Conc > 100 g/lit
• Blood sugar 100% normal
60
A Simple Introduction to Organ Transplant
Dr Gopi Ayyaswamy
1. Main aim is directed at optimizing transplantable organ function. High
quality critical care including chest physiotherapy, aseptic precautions
and antibiotics may be required.
2. Primary goals are maintenance of adequate tissue perfusion and
preservation of organ viability.
Duration of Donor Management
If high quality donor management was available, delaying transplantation
to improve donor condition is acceptable. The approach is “relax and
repair” rather than “rush and retrieve”. When the donor is stable retrieval
should be started since there is a risk of deterioration if retrieval is delayed.
The actual timing of retrieval depends on which organs are likely to be
retrieved and whether other organs will be transplanted even if function
improves.
Key Point
Prolonged cold ischemic time certainly has an adverse effect on the
function of all transplanted organs particularly hearts. Planning must
limit cold ischemic time and allow optimal timing for recipient operations.
Common Medical Problems in Brain Stem Dead Patient
• Hypotension
• Coagulopathy
• Diabetes insipidus
• Cardiac ischemia (IE arrhythmias)
• Renal failure
• Acute lung injury
• Acute respiratory distress syndrome
The Principles of Donor Management
General Care
1. Management in intensive care unit
2. Continued invasive monitoring.
Maintenance of Brain Dead Patients
61
Dr Gopi Ayyaswamy
3. Adherence to infection control practices.
4. Mouth and eye care.
5. Hygiene needs as required.
6. Regular patient repositioning.
7. Nursing with the head of the bed elevated to reduce the risk of aspiration.
Respiratory
1. Lung protective ventilation.
2. Tidal volume 6–8 ml/kg with optimal PEEP to allow minimum FiO
2
3. Recruitment manoeuvres to be maintained.
4. Maintain tracheal cuff pressure at 25 cm H
2
O.
5. Avoid overload with uids
Cardiovascular
1. Maintain uid balance
2. Correct hypovolemia-crystalloids preferred.
3. Since vascular tone is impaired, cardiac output monitoring may be
needed to titrate uids or presser drugs to intended goals as guided
by retrieval team.
4. Dose of vasopressin 0–2.4 units/hr (DA VP, 1–deamino–8–D–arginine.
Vasopressin)
5. High doses of catecholamine (e.g. nor-epinephrine > 0.05 µg/kg/min)
should be avoided, if possible.
6. Consider Triiodothyronine bolus and infusion. Dose: 4 µg bolus, then
infusion at 3 µg.h
–1
Or Levothyroxine.
Fluids
1. Administer maintenance uid (can use enteral route). But avoid positive
balance and hyponatremia.
2. Monitor urine output: 0.5–2.5 ml/kg/hr
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A Simple Introduction to Organ Transplant
Dr Gopi Ayyaswamy
3. If urine output is > 4 ml/kg/hr, consider diagnosis of diabetes insipidus
and treat with vasopressin infusion or DDVAP.
Nutrition
1. Insulin infusion 1 unit/hr minimum.
2. Maintain feeding or glucose source. Blood glucose target 4–8 mmol/lit
(80–160 mg%).
3. Electrolyte abnormalities to be corrected to normal values.
Blood and Coagulation
1. Correct coagulation if evidence of active bleeding.
2. Consider need for coagulation support during retrieval.
3. Consider need for transfusion.
4. Maintain thrombo prophylaxis as there is high incidence of pulmonary
emboli found at retrieval.
Steroids
Methylprednisolone 15 mg/kg bolus immediately after brain death
conrmed.
Investigations
1. Full Blood Count.
2. Urea. Creatinine, electrolytes.
3. Liver enzymes, INR, PT and PPT.
4. Blood glucose.
5. ABG.
6. Culture—blood, urine, sputum
7. ECG
8. Echocardiogram.
9. Coronary angiogram may be indicated.
Maintenance of Brain Dead Patients
63
Dr Gopi Ayyaswamy
10. Bronchoscopy and lavage followed by lung recruitment manoeuvres.
11. Chest X-ray after lung recruitment procedure.
12. CT, MRI, Doppler.
To increase the number of organs that meet the criteria for trans-
plantation, the medical care of the potential organ donor must be
protective and aggressive.
Note: Please consider these as guidelines only. It is advisable to refer to more current and advanced
medical literature for the most up-to-date information.