SSEP and anesthetics

General anesthesia has an inhibitory effect on neurotransmission and, therefore, on the EP. The effect of anesthetics is greater on synaptic transmission than on axonal conduction. For this reason, responses recorded from polysynaptic pathways (e.g., cortical recordings) are affected by anesthesia to a much greater extent than those recorded from oligosynaptic pathways (e.g., spinal cord and subcortical recordings).”

All volatile anesthetics produce a dose-dependent increase in SSEP latency and a decrease amplitude. All volatile anesthetics, even at concentrations above 1.0 MAC, only minimally affect the sub-cortical waveform, resulting in high recordability and reliability.

The effect of volatile anesthetics on cortical SSEP amplitude is compounded by nitrous oxide.

Intravenous anesthetics generally affect SSEPs less than inhaled anesthetics do.

Etomidate and ketamine increase SSEP amplitude.

Propofol, midazolam, and barbiturates have a moderate depressant effect on SSEP amplitude.

In a normothermic individual, SSEP monitoring can detect cerebral ischemia during barbiturate anesthesia at doses that induce burst suppression.

Most authors report minimal to no effect of opioids on SSEP amplitude.

Dexmedetomidine affects SSEP amplitude minimally at sedative doses. During isoflurane anesthesia, dexmedetomidine blunts the effect of isoflurane on SSEP amplitude

Comments

Things to Avoid in Anesthesia for Pregnant with Pulmonary hypertension

Anesthesia for Pregnant woman with Pulmonary Hypertension is a real challenge for anesthesiologist. It is very crucial to remember the pathophysiology of pulmonary hypertension in pregnant women and to avoid some practices that will worsen the cardiac status. 1-Avoid single shot spinal anesthesia. Some authorities consider pulmonary hypertension as absolute contraindication for single shot spinal anesthesia specially in patients with NYHA III ,IV. Spinal anesthesia causes major hemodynamic instability(decrease SVR, decrease VR, decrease in CO) The preferred neuroaxial techniques are (epidural anesthesia and CSE with minimal spinal dose) 2-Avoid PAC. Pulmonary Artery catheters insertion may lead to pulmonary artery rupture or thrombosis. TEE is better cardiac monitor/Arteial line is mandatory. 3-Avoid Nitrous oxide in gas mixture.N2O increase the PVR 4-If MV to be started, avoid High TV and PEEP 5-Avoid Oxytocin Boluses, or rapid administration of Pitocin. Oxytocin causes ...

power injectable peripherally inserted central catheters

Clinical experience with power injectable peripherally inserted central catheters in intensive care patients Introduction In intensive care units (ICU), peripherally inserted central catheters (PICC) may be an alternative option to standard central venous catheters, particularly in patients with coagulation disorders or at high risk for infection. Some limits of PICCs (such as low flow rates) may be overcome by the use of power-injectable catheters . Method We have retrospectively reviewed all the power injectable PICCs inserted in adult and pediatric patients in the ICU during a 12-month period, focusing on the rate of complications at insertion and during maintenance. Results We have collected 89 power injectable PICCs (in adults and in children), both multiple and single lumen. All insertions were successful. There were no major complications at insertion and no episodes of catheter-related blood stream infection. Non-infective complications ...

Lumbar and thoracic epidural in Pediatrics-Technical aspect

The midline approach is most commonly used. The ligamentum flavum is considerably thinner and less dense in infants than in older children and adults. This makes recognition of engagement in the ligament more difficult and requires both extra care and slower, more deliberate passage of the needle to avoid subarachnoid puncture. The angle of approach to the epidural space is slightly more perpendicular to the plane of the back than in older children and adults, owing to the orientation of the spinous processes in infants and small children. The loss of resistance technique should be used, but only with saline, not air. There are several reports of venous air embolism in infants and children when air was used to test for loss of resistance Use a short (5 cm) 18-gauge Tuohy needle and a 20- or 21-gauge catheter in infants and children. Epidural kits specifically for infants and children are available Maximum of 0.4 mg/kg/hr of bupivacaine after the initial block is estab...

sedationstation

Search This Blog