Addition of Hyalase to Local Anesthetic in Scalp Block Clinical Trial
Official title:
Safety and Efficacy of Addition of Hyaluronidase to Lidocaine and Bupivacaine in Scalp Nerves Block in Elective Craniotomy Operations, Comparative Study
Safety and efficacy of addition of hyaluronidase to lidocaine and bupivacaine in scalp nerves block in elective craniotomy operations,Comparative study
Patients undergoing craniotomy operations are susceptible to many injurious stimuli such as
skin incision, insertion of cranial pins, dural incision, dural and skin closure. They cause
different levels of nociception and these stimuli can result in sudden increases in blood
pressure and heart rate due to triggering stress response.
Strategies to blunt these noxious stimuli and attenuate this stress response include
administration of systemic opioids, deepening the level of anaesthesia. Scalp nerves block by
local anaesthetics also can be used.
However, most systemically administered medications studied for post-craniotomy pain usually
associated with side effects such as sedation, nausea, and vomiting and depressed ventilation
such events are particularly important for post-craniotomy patients.
Using regional aesthetic techniques in addition to general anaesthesia have been conducted as
multimodality managements for post-craniotomy pain and to decrease systemic administration of
analgesics and hence decrease their systemic complications.
The stress response is the hormonal and metabolic changes that follow injury or trauma. This
includes wide range of endocrinological and immunological effects. The stress response to
surgery is characterized by increased secretion of pituitary hormones and activation of the
sympathetic nervous system. Hypothalamic activation of the sympathetic autonomic nervous
system results in increased secretion of catecholamines from the adrenal medulla and release
of norepinephrine from presynaptic nerve terminals. IL-6 is produced in substantial
quantities at the site of a surgical wound.IL-6 enters the circulation, and its concentration
correlates with the severity of surgery and thus with the magnitude of the tissue injury. At
24 to 36 h after surgery, the levels of IL-6 in the plasma reach preoperative values, because
its production is attenuated. Postoperative pain behaves like wound on plasma IL-6: intense
postoperative pain correlates with the magnitude of tissue injury and subsides days after.
Pain in the first 24 hours after brain surgery is a significant problem, with 60% to 80% of
patients experiencing moderate to severe pain.
Blockade of scalp innervation which anesthetises both the superficial and deep layers of the
scalp, was used as a means of decreasing hemodynamic reactions during and after craniotomy
operations. Various protocols to control postoperative pain were suggested, including
infiltration of the scalp with local anaesthetics. These include the use of 0.5% bupivacaine
combined with additional lidocaine 2 %.
Hyaluronidase is a naturally produced enzyme, it's produced by various types of bacteria, and
primary helps bacteria to dissolve hyaluronic acid that constitutes major component of the
connective tissue substance thus helping spread of other bacterial products. On December
2005, the FDA approved a synthetic (recombinant or rDNA) human hyaluronidase. The addition of
hyaluronidase to local anaesthetics has been shown to enhance safely and effectively the
diffusion of the drug, thereby increasing the analgesic efficacy especially in the first
minutes after injection
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