Requirements

1) Pre sedation assessment. a) Concise medical history and examination.
                                                   b) Brief explanation of the procedure. 

INTODUCTION: The introduction of modern drugs and portable monitoring systems has prompted anaesthetist to leave the sheltered operating room work place and provide care in remote offsite locations .The recognition of the need for improved pain management has sponsored the move of anaesthesia care beyond the operating room. Infants and children are most often the patients who benefit from these, out of OR initiatives.
The technique of sedation involves the administration of drugs that depress the CNS. The objective of this technique is to produce the required degree of sedation so that the patient is comfortable during the procedure without cardio respiratory compromise.
Anaesthesia outside the OR.
1) Radiology –CT, MRI, Interventional radiation therapy.
2) Cardiology- Cardio version, Permanent pacemaker insertion, catheterisation.
3) Psychiatry- ECT
4) Gastroenterology- EGD, colonoscopy.
5) Urology-ESWL
PATIENT FACTORS REQUIRING SEDATION:
a)      Anxiety
b)       Claustrophobia
c)       Development and learning difficulties
d)       Cerebral palsy
e)       Seizure disorder
f)       Movement disorders
g)      Severe  pain  
h)      Acute trauma with unstable CVS, RS or CNS function
i)         Child age.
j)         Significant co morbidity 

 LEVELS of SEDATION defined by ASA.
 Minimal Sedation – Patient responds to command.
Moderate Sedation – Patient responds to commands with light stimulation. Ventilation and CVS states are maintained.
Deep Sedation- Patient not arousable, responds to pain, protective reflexes may be lost therefore may need assistance.
GA- Unarousable, intervention required for airway, CVS may be impaired.

                                                  c) Instruction regarding preparation of patient for procedure
                                                 d) Instructions regarding NPO
  2) FACILITIES:
                    The procedure should be performed in a location that is adequate in size and staffed and equipped to deal with cardiopulmonary emergency. This should include
a)      An operating table, trolley or chair which can be readily tilted.
b)      Adequate access to patient airway.
c)       Adequate lighting.
d)      There should be in each location an adequate and reliable source of suction. Suction apparatus that meets OR standards is strongly recommended.
e)      There should be a reliable source of oxygen for the whole length of procedure.
f)        Prior to administration of any sedation the practioner should ensure that oxygen supply and equipment is in working order.
Drugs used for sedation.
Chloral Hydrate and Triclofos- Effective oral sedatives.
Chloral Hydrate – Dose-25-50mg/kg for infants younger than 4 months.50-100mg/kg for older children. Disadvantages - Unpleasant taste & gastric irritation.
Triclofos - Palatable but less potent and slower in onset. Dose-1gm of Triclofos =600mg of chloral hydrate.
Benzodiazepine-
Midazolam- It can be given orally, intranasally, per rectum and intravenously
When given orally it is bitter in taste and needs masking with a sweetening agent. Dose- Oral 0.5mg-1mg/kg.  Intranasal- 0.2mg/kg will calm children. Sublingual administration is more pleasant, equally rapid & effective but requires cooperation. Rectal dose 0.3mg-1mg/kg.
IV titration is best but effects are variable. Dose-0.05-0.2mg/kg .For deep sedation-0.5mg/Kg.
Diazepam- Intravenous Diazepam is less potent than Midazolam.
Temazepam- Dose 0.5-1mg/kg. Orally causes anxiolysis and sleep. For MRI 1mg/kg of Temazepam is combined with Droperidol 0.25mg/kg orally.

Barbiturates-
 Thiopentone- Dose 25-50mg/kg per rectum produces sleep after 30minutes in  children.
Quinabarbitol -Dose- 7.5-10mg/kg oral
Pentobarbitol- Dose 2-6mg/kg intravenously.
Propofol - Best Intravenous agent because of short duration of action and lack of side effects.
Sleep dose-2-4mg/kg. Infusion rate6-8mg/kg/hr. Recovery is pleasant and within few minutes.
Melatonin- Natural sleep may be induced successfully. Dose-2-10mg orally.
Opiods- Used for painful procedures. Commonly used opiate is Fentanyl. It is absorbed from the mucosa of the mouth. Oral transmucosal Fentanyl is available as a large palatable lollypop.
Side effects- Vomiting and desaturation.
Ketamine-Can be used intramuscularly or intravenously or orally.
Dose -Oral-6mg/Kg, IM-5mg/kg, IV- 2mg/kg.
Dexmeditomedine; Its a sedative with minimal effects on respiratory drive and the carbondioxide
response curve.
Dose -loading-1.0µg /kg. Maintenance-0.2-0.6µg /kg /hr.
 In Patients with hepatic and renal compromise the dose has to be reduced.
Painful procedures;
Many children undergo repeated lumbar punctures, intrathecal injections and bone marrow aspirations. In cooperative children, behavioural techniques and conscious sedation using Midazolam with Fentanyl can be successful with local anaesthesia. Deep sedation with combinations of midazolam, opiods and Ketamine is possible in younger children. Painful procedures where the duration of procedure is unpredictable, procedures where the child has to absolutely immobile or endoscopic studies where gag reflex has to be suppressed  general anaesthesia is preferable.
Painless procedures:
CT Scanning-
Modern CT scan rooms have been built with anaesthetic requirements taken into account. These include piped in gas outlets and suction units. An anaesthetic supply cart fully equipped with anaesthetic drugs and airway adjuncts should be available. Monitors should be stacked in a place where it can be viewed through the window from outside. Some modern scanners have a closed circuit TV imaging of the patient as they lie within the tube allowing constant observation of the chest wall movement. Check monitors before starting the scan.
For elective CT scans patient should be assessed with careful history and physical examination.
Anaesthesia;
Chloral hydrate- 50mg/kg orally for children undergoing CT examination.
Propofol has now gained wide spread acceptance as a useful sedative in the radiology suite.
MRI-
 Environment is unique because of its strong magnetic field, high frequency electromagnetic waves and a pulsed magnetic field.
MRI safety Zones –
 Zone I- Freely accessible to all.
Zone II - Accessible to unscreened MRI patients.
Zone III - Screened MRI patient and personnel.
Zone IV- - Screened MRI patients under constant direct supervision of trained MRI personnel.
Problems with MRI;
1)      Prolonged periods of immobilisation may sometimes be required.
2)      Limited patient access.
3)      Absolute need to exclude ferromagnetic components.
4)       Interference of monitoring equipment produced by the changing magnetic field and RF current.
5)      Potential degradation of imaging caused by stray RF currents produced by monitors.
6)      Aquastic noise.
7)      Burns caused by RF current.
Monitoring for MRI.
ECG- Telemetric ECG now available. Liquid crystal display to avoid distortion. Graphite electrodes to
avoid burns. Avoid loops of wires.
BP – Indirect measurement is possible by using nylon connectors.
Capnograph – Side stream sampling should be used but necessitates a long sampling tube.
Pulseoximeter – Non ferromagnetic model is available.
Anaesthetic Equipment-
Laryngoscope – Standard batteries are highly magnetic.
ETT- Avoid reinforced tubes and metal connectors.
LMA- Spring in valve may distort image.
Anaesthesia Machine –Several non magnetic machines are available. Aluminium cylinders are available.
Infusion pumps-Extension sets are recommended to minimise field effect on motor.
Suction- Wall mounted with 10m tubing.
Defibrillator- Cathode ray tube and batteries malfunction within 30gauss line. Resuscitation should be carried out outside the magnetic field  
Anaesthesia- Type of anaesthesia depends on duration of procedure, age of the patient, physical state of patient and the availability of MRI compatible equipments.
Conclusion;
Most children under the age of five years require sedation or GA for investigatory procedures. 
Oral sedation technique if appropriately administered has 93% success rate.
During deep sedation protective reflexes are lost, so patient should be monitored carefully.
In case of emergency all procedures have to be stopped and patient has to be resuscitated.