*Lung

*Breast

*GI

*Tumor location

-Determines position, EBL, risk for VAE

*Growth rate and size

-Slow growing often asymptomatic

*ICP

-Determine if ICP is elevated

*Control the ICP

-Use steroids, diuretics, hyperventilation

*Maintain the CPP

-CPP=MAP-ICP (normal 80-100mmHg)

*Protect patient from position related injuries

*Rapid emergence for neuro assessment

-Exceptions are those who arrive vented and unresponsive

*Assess for increased ICP

*Document LOC, Neuro deficits

*Review PMH & general health status

*Review medication regime

*Review x-ray findings

*Review lab findings/T&C

*If ICP is increased avoid Midazolam

-Can result in too much sedation, increase in CO2 which increases ICP and Decreased LOC

*Use caution with all other patients to avoid respiratory depression

*Midazolam acceptable when ICP is normal

*Continue steroids and anti-seizure meds 

*2 large bore IVs preferred 

*Possible central line

-For VAE monitoring and treatment

*Arterial line helpful

-BP control, CO2 monitoring, CPP calculation, VAE

*PNS monitoring MANDATORY!

*Foley catheter

-Monitor I&O and effect of diuretics

*Maintain normal CPP and avoid ICP increases with slow induction

What drugs should be given for induction in the patient undergoing an

intracranial lesion surgery?

*Thiopental or Propofol (Be heavy handed with induction agent)

*NDMR if appropriate, SCh if necessary

*Opioid

*Lidocaine

*Opioid such as fentanyl

*Lidocaine 1.5mg/kg to blunt stimulating effects of laryngoscopy

*Can't give too much fluid too quickly because cerebral edema can result.

*Must use pressors to maintain appropriate CPP

*Anticipate turining OR table

*Insure ability to access all vital equipment

-Adequate extension sets for IV

-Stop cocks in reach

-Long breathing circuit

*Patient may be prone, sitting, even lateral

*HOB often elevated 10-15 degrees

*Avoid N2O, can cause pneumocephalus.  

*Those with repeat craniotomies are at a higher risk.

*Get rid of agents that could increase cerebral blood volume such as Opioids and forane.  

*Switch to TIVA

*Use isotonic glucose-free crystalloids

*Maintain hypovolemia

*avoid hypotonic fluids

*If severe cerebral edema or increase ICP exists, use less normal maintenance rate (1.5mL/kg)

*Avoid hyperglycemia (200g/dL or less)

*Replace blood loss with blood or colloids

*Avoid large fluid boluses

*HTN can cause autoregulatory breaththrough (disruption of the blood brain barrier)

*This results in cerebral edema formation

*Increase in ICP

*May cause intracerebral hemorrhage

*Consider Pre-op neuro status

*Location and duration of surgery
*Extend of cerebral edema

*Decide with surgeon

*If decision is made to extubate, avoid coughing or bucking on ETT

*During closure, decrease volatile agent and teak in antihypertensives to control BP

*Slowly DC hyperventilation to prevent rebound vasodilatory effects

*Return spontaneous respirations

*Reverse NDMR and DC agent AFTER dressing is on and table turned

*Blunt cough with lidocaine, opioid, and thiopental

*Hypercarbia possible which may increase ICP

*Contraindicated in tenuous airway

*Evaluate HOB for transport

*O2

*manage hypertension

*Post op pain is minimal

*Infratentorial due to its close proximity to cerebellum and brainstem which controls the ANS, CV and respiratory centers, RAS, and Motor/sensory pathways.  It also contains CN I thru XII and large venous sinuses surround the surgical area.

*Operative approach and positioning

*Effects of brainstem stimulation

*Possibility of increased ICP

*Potential for air embolism

*Assess for increase in ICP

*Check for brainstem involvement

*Presence of CV or pulmonary disease

-CV px will possibly effect positioning options

-Pulmonary px can result from aspiration d/t possible reflex compromise

*Assess overall lab values and neurodiagnostic studies

*Routine ++++

*Detection of VAE d/t greater propensity of occurence d/t proximity of dural venous sinuses to infratentorial contents.

*Evoked Potentials

*ICP not typically monitored d/t becoming atmospheric when dura is opened.

*Oral-Pharyngeal airway d/t resultant Oral-Pharyngeal compression and Macroglossia

*Oral-Pharyngeal Compression

*ETT may kink d/t flexing of neck, use anode tube.

*Flexing can cause quadriplegia

*Check padding on horseshoe headrest to prevent ischemic optic neuropathy.

*Improved surgical exposure

*More anatomically correct

*Less retraction and tissue damage

*Less Bleeding

*Less Cranial nerve damage

*Better resection of the lesion

*Access to airway, chest, and extremities

*Postural hypotension

*Arrhythmias

*Venous pooling

*Light anesthesia during positioning

*Paralysis

*Volume load; vasopressors

*Leg Wraps

*Move into position slowly

*Pneumocephalus

*Nerve injuries

*Cardiovascular compromise

*Open dura--> CSF Leak-->Air enters.  After dural closure air can act as a mass lesion as CSF reaccumulates 

*Usually resolves spontaneously, but if a tension pneumocephalus results a surgical intervention is required such as a burr hole.

*S/S include: delayed awakening, headache, lethargy, confusion

What nerve injuries can result from the sitting position for posterior cranial fossa surgery? How can these be prevented?

*Ulnar Compression

-Arms across abdomen; pad elbows

*Sciatic Nerve Stretch

-Pillow under knees

*Lateral peroneal compression

-Pad knees

*Brachial plexus stretch

-Pad under arms to support shoulders

*Semirecumbant "lounge chair"

*HOB elevated 60 degrees 

*Legs elevated

*Knees flexed

*Arms at sides and flexed on abdomen

*Leg wraps

*Skull fixation device applied (VERY STIMULATING)

*Paralyze and lighten Anesthesia (If too deep BP will drop)

*Slowly adjust OR Table into seated position

*Watch BP and EKG at all times

*Check breath sounds

*Normocarbia

*2 large bore IVs

*4u PRBCs on hold

*Run on dry side if CV stable

*Diuretics and decadron ready

*Replace blood loss with blood

*If surgery is superficial and atraumatic ok, want alert and cough/swallow reflexes back

*If surgery is lengthy, lesion is deep, lots of retraction, ventilated pre-op, leave patient intubated

*Monitor for edema or hematoma

*Apnea d/t brainstem manipulation

*CN Dysfunction (all of which control the pharynx and larynx)

-CN IX Glossopharyngeal

-CN X Vagus

-CN XII Hypoglossal

*Manage Hypertension

*Alterations in HR&BP

*Arrhythmias frequent

*At emergence may see abnormal breathing pattern

*Alert surgeon if these "warning sign" changes occur

*May occur anytime the incision is >5cm higher than the heart.

-The larger the gradient the higher the risk

*Veins higher than the right atrium have a lower intravascular pressure than the heart

-A negative pressure can even result

*When the pressure in the veins is subatmospheric, the can entrain air

*Venous sinuses can act as the conduits for air entry

*Can enter in a slow or rapid manner

*Small bubbles enter and travel to heart

*Pulmonary circulation, lodge in capillary beds--> vasoconstriction

*PVR increases --> V/Q mismatch

*Excreted Via lungs

*Continued entrainment will overload excretion capacity

--> increase in PAP & CVP

*RV Failure may develop

*Cardiac output will decrease 

*The increase in deadspace will lead to decrease in EtCO2

*Large EtCO2; PaCO2 gradient

*Arterial PO2 will decrease

*0.15mL/kg/min is tolerated

*>1.8mL/kg/min is FATAL

*Occurs when large bubbles enter

*Lodge in SVC, RA or RV

*Impede flow through right heart

*Slow increase in PAP-->pulmonary outflow obstruction

*CO&BP will decrease

*Reflex bronchoconstriction and pulmonary edema occur

*Acute Cor Pulmonale & anoxia cause death

*Symptoms occur with 1mL/kg

*4-7mL/kg are FATAL!

*Dissection of skin or muscle

*Turning of the craniotomy flap

*Dissection of vascular tumor beds

**Most VAE occur within the first hour of operation!

*Air enters left side of heart

*Travels to systemic circulation

*Two major circulations at risk

-Coronary

-Cerebral

*Occurs when right heart pressure is greater than left heart pressure

*Most commonly seen in patients with PFO

-PFO has a 10-25% incidence in adults

*Prevention

-Monitor PAP&CVP

-Don't allow a right>left gradient

*If cardiac murmur detected preop, have echo performed (or don't do surgery seated)