Question to Dr. Berg: Motor and sensory blockade
March 22, 2015 | 20,00 EUR | answered by Dr. med. Ralf Berg
Hello, I have two questions regarding pain control during a cesarean section with regional anesthesia.
Specifically, it is about the MOTOR AND SENSORY BLOCKADE.
1. Let's assume one of your patients is having a cesarean section with epidural anesthesia.
I have read that there is a Motor Blockade and a Sensory Blockade.
How exactly would it manifest, or what would the feelings be during the cesarean section if the MOTOR blockage is not completely eliminated?
As a complete novice, I would interpret it as follows:
With an incomplete Sensory Blockade, the patient would experience severe pain and may need to switch to general anesthesia.
With an incomplete MOTOR blockage, one might feel the instruments in the abdomen or some sort of force during the surgery, possibly experiencing the procedure more intensely, related only to motor function. But would there be pain with an incomplete Motor Blockade during a cesarean section, or how would that manifest?
Am I correct or incorrect with these two conclusions?
2. In the case of a high/total spinal anesthesia (where the planned anesthetic for an epidural anesthesia is accidentally injected into the spinal space), would there actually be pain? I would assume not, as the anesthesia would completely eliminate the pain due to its high dosage reaching the spinal space, being highly effective. Am I wrong with this conclusion as well?
Thank you, kind regards.
Hello,
the topic doesn't let you go......
So, with epidural anesthesia, it is a question of the dose of the local anesthetic that is injected into the epidural space. For a spontaneous birth, one tries to inject only enough so that the sensitive nerve fibers = the pain nerve fibers, are completely or partially blocked, so that the pain of contractions is more or less alleviated, but the woman can still move her legs and the muscles of the abdominal press.
In the case of a cesarean section, by "topping up," that is, the re-administration of a higher concentration of local anesthetics into the epidural space, both the sensory and motor blockade are achieved. An operation without motor blockade is not possible, as the patient will involuntarily twitch every time the electric cutting of the muscle, or the electric hemostasis, which is nothing but targeted electric shocks, is applied.
The art of dosing in this case is to give only enough that the blockade does not rise higher than the belly button. Unfortunately, this is not always successful for various reasons.
The second conclusion is correct, with the slight addition that the cause of a high spinal anesthesia, in addition to an unintentional puncture of the spinal space, may also be an unexpectedly high rise in the epidural space. The reasons lie not only in the absolute amount of the anesthetic, but can also be due to different anatomy, contractions, altered tissue pressure during pregnancy.
Your considerations in the middle part, switching to general anesthesia if epidural/spinal anesthesia is ineffective, are also correct. However, in the case of high spinal anesthesia, one must switch to general anesthesia in order to gain control over breathing, not because of any sensory or motor blocks. If the nerve supplying the diaphragm is completely paralyzed, the patient would become hypoxic and ultimately suffocate without countermeasures.
The fact that you experienced a phase of hypoxia with decreased respiratory drive can be inferred from the oxygen and CO2 values.
Whether, when, and especially how intensively/aggressively to address this (only oxygen administration, assisted mask ventilation, intubation), depends on the situation. With each minute after injection, the effect of spinal/epidural anesthesia diminishes. The last (high) nerve segments to fail recover first.
It is important that this critical phase is bridged. In order to spare the patient the uncomfortable experience, in addition to oxygen administration/ventilation, the patient is sedated, or if necessary, put under anesthesia.
Have all questions been answered for this evening?
Feel free to call me at the phone number provided.
Best regards,
Dr. R. Berg
