Airway part 2 and LPs Flashcards
Indications for an LP
CSF analysis to evaluate for subarachnoid hemorrhage, meningitis, encephalitis, subarachnoid bleed, intracranial pathology, CNS infection, HA workup, etc.
To drain CSF or measure CSF pressure
For spinal anesthesia to inject meds
CIs for an LP
Relative CI in its with coagulation defect or platelets <50,000
Increased ICP
-Creates pressure differential- herniates brainstem
Skin infection overlying area where LP is to be performed
Previous lumbar surgery (increases difficulty but may not be absolute CI)
Equipment needed for an LP
Spinal needle - <1 yr: 1.5 in - 1 yr to middle childhood: 2.5 in -Older children and adults: 3.5 in Three-way stopcock Manometer for pressure measuring 4 specimen tubes Local anesthesia Drapes Betadine
How to utilize aseptic technique
Skin prep
Gloves
Drape
Mask
What must be done before every procedure for an LP?
Get informed consent (will take a few minutes or you’ve done a bad job!)
Must discuss complications
Location of LP
Spinal cord ends in caudal equine around L1-L2, so do LP at L2-3 or lower
L3-4 is preferred (less likely to damage spinal cord)
What needle to use for local anesthesia before LP
25-27 gauge needle
Pt position for LP
Lumbar flexion
Make sure pt does not bend at the hips
Use helper for positioning help because you’re sterile
Can hit bone if not properly positioned
Needle size for actual LP
20-22 ga. (or smaller)
Avoid 18.19 ga
Anatomy of an LP
Going after subarachnoid space
Dura is thicker than subarachnoid
Can feel resistance of dura
Palpate the iliac crest to find lumbar level
What is the approach for an LP?
Midline approach (palpate spinous processes)
Procedure of the LP
Check for fluid-measure opening pressure; but if suspect elevated CSF pressure, should do head CT first
Collect 4 tubes of fluid (approx 1 mL each)
Withdraw needle, hold pressure
Apply dressing
Bedrest with no elevation of HOB 2-5 hrs
Hydration
What occurs when pressure is nl in an LP?
What occurs with increased pressure in an LP?
If nl, there will be a steady drip
If increased, there will be a fast stream
-Think about withdrawing needle
What are the typical studies obtained for a diagnostic LP?
Tube #1: Protein and glucose (chemistry)
Tube #2: Cell count and differential
Tube #3: Gram stain and culture
Tube #4: Hold for further studies
Optional CSF studies
Viral studies
Repeat cell counts (look for change from tube #2 to tube #4; indicates traumatic tap, i.e blood in sample)
Cytology
Immunology
Nl CSF results
Appearance- clear Pressure 50-175 mm H2O Spec gravity 1.006-1.009 Nl neg -Gram stain -Culture -Serology Glucose: 40-80 mg/dL Total protein: 15-50 mg/dL RBCs: none (unless traumatic tap) WBC: 0-5/micoL Diff: 60-80% lymph 10-30% mono
Abnl CSF results- total protein
Bacterial meningitis: 50-1500 mg/dL
Viral meningitis: nl to increased
HIV: 50-100 mg/dL
Fungal infection: 500-2000 mg/dL
Abnl CSF results- WBCs/microL
Bacterial meningitis: 1000-5000 (monocytes)
Viral meningitis: 10-1000 (lymphocytes)
HIV: 300 or more
Fungal: 50-1000 (varies, eosinophils)
Abnl CSF results- glucose
Bacterial meningitis: low (slightly to very low)
Viral meningitis: nl to slightly low
HIV: nl
Fungal: nl to slightly low
LP traumatic tap
Doesn’t mean trauma in the usual sense
Refers to nicking a blood vessel, which then releases some blood into the CSF
Dura is surrounded by network of epidural veins; small penetrating branches of vessels in subarachnoid space
Totally unrelated to poor technique, rather is just a statistical reality
Blood gradually clears from CSF so cell count 4th tube is decreased compared to 2nd tube
Potential complications of an LP
Postdural HA (usually very severe HA) Nerve damage Bleeding-epidural hematoma Infection (meningitis, abscess) Needle breakage
Postdural HA
MC complication of LP
F > M, youth > aged
Positional HA- supine better, sitting/standing worse
Related to needle size (>size = > risk) and technique
Caused by change in pressure CSF pressure or continued fluid leak; appears in several hours to few days
Can be a very severe, debilitating, front-occipital HA; nausea is common
Tx for postdural HA
Hydration
Bedrest
Caffeine
If not improved in 48 hrs, epidural blood patch
Epidural hematoma
Insidious onset
Hrs to a day or two after an LP or epidural
Causes pressure on spinal cord; ischemia
Results in nerve damage, paralysis
Surgical emergency; evacuation of hematoma
Numbness, leg weakness, loss of bladder or bowel control- pay attention
Tube thoracotomy definition
The insertion of a tube (chest tube) into the pleural cavity to drain air, blood, bile, pus, or other fluids. Allows for continuous, large-vol drainage until the underlying pathology can be more formally addressed
What can occur if chest tube insertion is not properly clamped or sealed?
Pneumothorax
Indications for tube thoracostomy
Pneumothorax- open or closed, tension
Hemothorax- (hemopneumothorax, hydrothorax, chylothorax)
Empyema
Pleural effusion
Pts with penetrating chest wall injury who are intubated or about to be intubated
CIs to tube thoracostomy
The need for emergent thoracotomy- absolute
Relative:
-Coagulopathy
-Pulmonary bullae
-Pulmonary, pleural, or thoracic adhesions
-Loculated pleural effusion or empyema
-Skin infection over the chest tube insertion site
Tube thoracostomy procedure
After infiltrating insertion site with local anesthetic, make a 2-3 cm incision through skin and subcutaneous tissues between the 4th and 5th ribs, parallel to the rib margins in anterior axillary fold
Remember intercostal veins, arteries, and nerves lie in fossa on inferior surface of ribs
Thoracostomy complications
Bleeding from an injured intercostal artery (running from the aorta)
Accidental injury to the heart, arteries, or lung resulting from the chest tube insertion
Local or generalized infection
Air leaks in the tube, train, manifold
Disconnection or dislodging of the tube
Tension pneumothorax
Standard peripheral IV lines
Inserted in veins of forearm or hand. May be inserted into veins of lower extremities in neonates and infants
Use of standard peripheral IV lines
The delivery of non-irritating fluids and meds
Where to avoid in a standard peripheral IV line
Areas of lesion and superficial or deep nerves of the wrist
When to not use standard peripheral IV lines
Do not use as a permanent access when irritating or vesicant meds are medically necessary (pH <5 or >9; final osmolarity >600 mOsm/L)
Require central venous administration
When to replace peripheral IV lines
Every 72-96 hours When clinically indicated based on assessment of: -Pt's condition -Access site -Skin and vein integrity -Length and type of prescribed therapy -Venue of care -Integrity and potency of VAD, dressing and stabilization device
What to consider when choosing an IV access device
Diagnosis determines need/indication
Prescribed therapy (which particular medications)
Med characteristics (osmolarity, pH, chemical nature)
Duration of therapy
-Up to 2 days= PIV; 2 days to 4 wks = midline; 4 wks to 1 yr = PICC
Types of central venous lines
Single or multiple ports
Insertion- axillary, subclavian, int. jug., femoral vein
Percutaneous or subcutaneous
-Standard CVL usually int. jug or subclavian vein
-PICC lines; proximal arm veins (cephalic, axillary, brachial, basilic)
-Implanted for longer term use
-Midline is not a CVL because distal port lies in upper arm/ axillary vein
Periphally inserted central catheters (PICCs)
Inserted through a peripheral vein with tip residing in superior vena cava
-Optimal tip location is lower 1/3 of SVC at or above atrial-vena naval junction
Anything short of SVC placement is NOT considered a PICC and is not appropriate for use
Duration of PICCs
No established dwell time for PICCs
Use of PICCs
Short-term and long-term therapy, generally >5 days. Can be used for years if properly maintained
Groshon valve for CVL
Valve is closed when no pressure
Positive pressure from syringe opens valve outward for fluid administration
Negative pressure opens valve inward for blood draw
Flush with NS- no heparin
Indications for CVLs
Hemodynamic pressure monitoring- CVP (central venous pressure) or PA (pulmonary arterial)
Large-bore IV access
-Rapid infusion; vol resuscitation
-Blood transfusion; plasmapheresis
Prolonged venous access required or anticipated
Insert trans venous pacing or Swan-Ganz cats
Infusion of meds not compatible with peripheral veins (TPN, abx, chemo)
Failed or inadequate peripheral access- routine meds or blood draws
Absolute CIs for CVLs
Pt refusal
Infection at insertion site
Anatomical variance at the insertion site
SVC syndrome (except femoral venous line)
Relative CIs for CVLs
Coagulopathy
Systemic infection
Right-sided ventricular assist device
Presence of indwelling catheters or pacing wires at the insertion site
Mural thrombus
Caused by irritation of the vessel wall by the catheter. Results in accumulation of fibrin and blood components.
Catheter can eventually adhere to vessel wall.
Thrombus eventually forms.
Care of CVLs
Strict sterile technique; 100% compliance with every single port, every single time it is accessed.
Notice dressing, intact sutures, positioning (has it been withdrawn or over-inserted)
Check for ability to aspirate venous blood
Flush after use with saline, or hep-lok
Sx of complications of CVLs
Tachycardia Cardiac tamponade Dyspnea SVC syndrome Pneumo/hydro-thorax Fever
Most impt concepts of spirometry
VT-tidal volume in nl pos is only a small portion of VC- vital capacity FVC
When needed, we can inhale more vol (inspiratory reserve vol) and exhale more vol (expiratory residual vol)
After complete exhalation, there is still a residual art of air left in the lungs (TLC- RV)
Pulmonary dz affects these vols- reduces IRV, and restricts expiratory flow, increasing the time it takes to exhale (FEV and FEV1)
Acute resp failure
Can progress quickly and is unpredictable It is impt to recognize and intervene in an early and "elective" way if possible Waiting for the pt to "crash" increases the difficulty and risk of intubation and subsequent management of resp failure Opposite mistake (pulling the trigger too early) on airway manipulation, intubation, and MV is also to be avoided
Intubation indications
Pt’s inability to maintain and protect patent airway
Failure/insufficiency of oxygenation or ventilation
Anticipated need that is based on clinical course or tx requirements- airway, pulmonary, cardiac, neurologic, sepsis/shock, pending surgery with general anesthesiaq
Indications for mechanical ventilation
Failure to oxygenate blood-
-Pulmonary dz (acute or chronic, shock, anemia)
Failure to adequately ventilate
-V/Q abnormality, apnea, paralysis, CNS issue
Frequently, indications for MV are combo of both of above
Mechanical ventilation modes
CMV- controlled mechanical ventilation AC- assist control IMV- intermittent mandatory ventilation SIMV- synchronized IMV PSV- pressure support ventilation CPAP- continuous positive airway pressure Tube compensation All but CMV allow for some (and/or assist) spontaneous ventilation (pt trigger ventilation)
Ventilation parameters and considerations
O2 concentration- FiO2
Tidal volume
RR
PEEP (positive end expiratory pressure)- in cm, frequently 5 cm, prevents alveoli closure
Peak, plateau, and mean airway pressures- barotrauma = lung damage from excess pressure
Auto-PEEP: air trapping in ventilated pt, can treat with CPAP and increase in expiratory time
Ventilator changes for respiratory acidosis or alkalosis
(pCO2)1 (VT1 x RR1) = (pCO2)2 (VT2 x RR2)
When to wean from mechanical ventilation
Reverse primary dz process (including nutrition) Meds, other txs stabilized Hemodynamically stable Adequate neurologic status FiO2 < 50% PEEP < 8 RR < 30 RR/VT < 105 (rapid-shallow index) NIF > 25 VC >2 x VT
