| Surgery•urology•Anaestheology
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●General ☉prophylactic Abx clean wound: ★without implants, short time: thyroid, breast, hernia →→not necessary clean-contaminated: eg. gastrectomy, cholecystectomy →→1st cefa /+aminoglycoside contaminated: 2nd cefa + aminoglycoside ☉TPN →indication 1.enterocutaneous fistula/ ileus 2.pancreatitis 3.burn, sepsis 4.IBD →complication 1.catheter-related(phlebitis....) 2.cholestasis 3.MALT, bac translocation 4.hepatic, metabolic dysfunction(DM, hyperlipidemia) ☉intracellular: Na 12 K 140 extracellular: Na 145 K 4 ●Breast ☉breast ca: 零 期： 即原位癌，為最早期乳癌，癌細胞仍在乳腺管基底層內。 第 一 期： Size<2 cm 浸潤癌, no meta 第 二 期： Size: 2-5cm 浸潤癌;或Size<2 cm但腋下淋巴結有癌轉移。 第 三 期： IIIA: 局部廣泛性乳癌，Size>5 cm浸潤癌且腋下淋巴結有任何癌轉移。 IIIB: breast skin, chest wall, or internal mammary lymph nodes & inflammatory breast cancer("peau d'orange"). 第 四 期： 轉移性乳癌，已有遠處器官轉移(supraclavicular lymph nodes, lungs, liver, bone, or brain) ☉Breast ca.→infiltrating ductal carcinoma most commmon prognostic factor: axillary LN meta number recurrent factor: tumor size, ER, nuclear grade ☉Rotter's nodes : lymph nodes occasionally found between the pectoralis major and minor muscles which often contain metastases from mammary cancer . ☉Ductal Carcinoma in Situ →two type of DCIS distinguished by pathological analysis: non-comedo and comedo. Comedo type breast tumors have necrotic dead cells inside of them, non-comedo do not have necrosis. Comedo-type DCIS tends to be more aggressive than non-comedo types. ☉Phyllodes Tumor →rare breast tumor forms from the stroma of the breast, in contrast to carcinomas which develop in the ducts or lobules. Phyllodes tumors are usually benign, but on rare occasions have been found to be malignant. →do not respond to hormonal therapy and are less likely to respond to other breast cancer treatments such as chemotherapy or radiation therapy. As a result, benign phyllodes tumors are treated by removing the mass and a narrow margin of the surrounding breast tissue. Malignant phyllodes tumors are removed in the same manner with a wider margin of breast tissue, or by mastectomy. ☉Paget's disease →extramammary Paget's disease. Most cases of extramammary Paget's disease are thought to arise from apocrine glands. The redness, oozing, and crusting closely resemble dermatitis, but the physician should suspect carcinoma because the lesion is sharply marginated, unilateral, and unresponsive to topical therapy. →Biopsy of the lesion shows typical histologic changes(Epithelial malignant cells). An underlying carcinoma should be sought in all cases. Treatment is determined by the surgeon, but mastectomy is usual for lesions of the nipple. ●Chest ☉連枷胸（flail chest）：當單側肋骨骨折超過三根以上時，可能產生致命的反向呼吸運動（paradoxical respiratiory motion） ☉aortic hiatus thoracic duct, azygous vein, minor lymphatics(Vagus n. by esophagus就近支配也) ☉leiomyoma: most common benign esophageal ca., male> female（男生：胸部平的） ☉Esophageal ca. 1. SCC: 90% →carcinogens,thermal effect, Plummer-Vinson syndrome, Achalasia, Celiac spruce 2. Adenocarcinoma: 5% (common in west) →lower 1/3 →acid regurgitation, barrett's esophagus ☉Achalasia of the cardia or cardiospasm →Degeneration of the esophageal myenteric plexus of Auerbach, selective loss of inhibitory postganglionic neurons from the Auerbach plexus ,NO and VIP are inhibitory neurotransmitters responsible for relaxation of the LES and for coordinated esophageal peristalsis. →★"bird-beak" appearance →Oesophageal manometry is sometimes carried out although not essential. It would show increased peristalsis in the upper part and a tight lower oesophageal sphincter (LOS). →injection of Botulinum toxin into the lower oesophageal sphincter endoscopically →Heller's cardiomyotomy ☉Plummer-Vinson syndrome →iron-deficiency anaemia, atrophic changes in the buccal, glossopharyngeal, and oesophageal mucous membranes, koilonycha (spoon-shaped finger nails), and dysphagia. →The dysphagia is due to a web formed in the postcricoid region. →Carcinoma of the tongue and postcricoid region are complications. →most common in middle aged women, rarely in the male ☉Mediastinal tumor Ant: 3T1L: thymoma, thyroid(goiter), teratoma, lymphoma, metastatic ca.(most common 2) Mid: Bronchiogenic cyst, LAP, AA, esophageal ca Post: Neurogenic tumor ☉Lung Volume Reduction Surgery for emphysema ●Cardiology ☉Op indication: MR: LVESD > 45mm AR: LVESD > 50mm AAA: > 6cm ☉CAD Op indication 1.LM stenosis> 50% 2.3vd + LV dysfunction or 1v stenosis 3.2vd + LV dysfunction or LAD stenosis 4.1vd + LV dysfunction + LAD stenosis ☉CABG vessels: great saphenous v. cephalic v. radial a. ☉CV surgery 1.Rastelli: 2.Fontane: →used in congenitla tricuspid atresia, pulmonary atresia →The right atrium is anastomosed to the pulmonary artery either directly or via a conduit. 3.Jatane: TGA ☉PAOD Acute: 5P: pain, pallor, pulselessness, paresthesia, paralysis→Embolectomy Chronic: 1.Raynaud's phenomenom, 2. Intemittent Claudication, 3. Pain on rest, 4. Gangrene→★Bypass surgery ☉Ankle-brachial index test →by measuring blood pressure at the ankle and in the arm while a person is at rest. Measurements are then repeated at both sites after 5 minutes of walking on a treadmill. →By dividing the highest blood pressure at the ankle by the highest recorded pressure in either arm, the ankle-brachial index (ABI) can be calculated. The ABI result is used to predict the severity of peripheral arterial disease (PAD) that may be present. →resting ankle-brachial index of less than 1 is abnormal. If the ABI is: Less than 0.95, significant narrowing of one or more blood vessels in the legs is indicated. Less than 0.8, pain in the foot, leg, or buttock may occur during exercise (intermittent claudication). Less than 0.4, symptoms may occur when at rest. 0.25 or below, severe limb-threatening PAD is probably present. ☉DVT: Homan's sign: calf tenderness with foot dorsiflexion ●Gastroenterology ☉Gastric supplies: 1.Left/right gastric a. (celiac/ common hepatic) 2.Left/right gastro-omental a. (splenic/ gastroduodenal) 3.Short gastric a. (splenic a.) ☉Duodenal supplies: 1.Supraduodenal a. 2.Right gastro-omental a. 3.Sup/inf. pancreaticoduodenal a. →back wall: gastroduodenal a. rupture ☉Black pigment stone: hemolysis ☉Acute abdomen in elders: biliary tract dz. most common ☉Duodenal ulcer op: truncal vagotomy + antrectomy ☉Whipple: 胰頭十二指腸切除 ☉Superior Mesenteric Artery Syndrome →compression of the third, or transverse, portion of the duodenum against the aorta by the SMA, resulting in chronic, intermittent, or acute complete or partial duodenal obstruction. →Any factor that sharply narrows the aortomesenteric angle to approximately 6-25° can cause entrapment and compression of the third part of the duodenum as it passes between the SMA and aorta, resulting in SMA syndrome. ☉Blind loop syndrome (Stasis syndrome) →part of the intestine becomes blocked, causing too much bacteria to grow in the intestines and causes problems in absorbing nutrients. →bile salts needed to digest fats become ineffective, resulting in fatty stools and poor absorption of fat and fat-soluble vitamins. →★Vitamin B12 deficiency(Megaloblastic anemia) may occur because the extra bacteria which develop in this situation use up all of the vitamin. →a complication that occurs after many operations, including subtotal gastrectomy (surgical removal of part of the stomach), operations for extreme obesity, or as a complication of inflammatory bowel disease or scleroderma. ☉Rapid Gastric Emptying (Dumping Syndrome) →jejunum fills too quickly with undigested food from the stomach. →"Early" dumping begins during or right after a meal. Symptoms of early dumping include nausea, vomiting, bloating, diarrhea, and shortness of breath. →"Late" dumping happens 1 to 3 hours after eating. Symptoms of late dumping include weakness, sweating, and dizziness. Many people have both types. →Stomach surgery is the main cause of dumping syndrome because surgery may damage the system that controls digestion. Patients with Zollinger-Ellison syndrome may also have dumping syndrome. →Treatment includes changes in eating habits (drink liquids between meals, not with them) and medication(somatostatin). ☉Recurrent stone: 2 years after cholecystectomy ☉Calot's Triangle: →inferior surface of the liver superiorly, cystic duct inferiorly, and common hepatic duct medially. →clean dissection of Calot's triangle necessary in cholecystectomies →Although the original description of this area gave the cystic artery as the superior border, the inferior surface of the liver is now accepted as this border. ☉Hemorrhoid 3,7,11 o'clock ☉anal fissures/fistulas →In anal fissures, anus distal to dentate line is involved. About 90% of anal fissures occur in the posterior midline where skeletal muscle fibers that circle the anus are weakest. The remaining 10% are found in the anterior midline. →Most anal fistulas originate in anal crypts, which become infected with abscess formation. When the abscess is opened or ruptures, a fistula is formed ☉Levator ani: puborectalis m. pubococygeous m. iliococcygeous m. ☉Diverticulitis Dx: →Abdominal pain and fever, Altered bowel habit, especially constipation(common) →x ray, CT(no colonoscopy or LGI series) →Contrast enema is only useful in mild-to-moderate cases of diverticulitis when the diagnosis is in doubt. Water-soluble contrast should be used. Otherwise, it should be delayed until the acute episode is resolved. However, this is not the investigation of choice. →CT scan of the abdomen is considered the optimal method of investigation in patients suspected of acute diverticulitis. →Endoscopy is not usually used in the evaluation of acute episodes of diverticulitis because of the possibility of perforation and subsequent development of peritonitis. →check CBC, Amylase ☉Diverticulosis →Diverticular Hemorrhage: Bleeding may occur from the diverticulum in 5% of patients. It is usually sudden in onset, painless and substantial. Diverticulosis is the cause in 30 to 50 percent of cases with massive bleeding from the colon. →Bleeding is usually not seen during an acute episode of acute diverticulitis. Diverticula bleed when they are otherwise healthy. →barium contrast enema: globular small protrusions from the lumen of the colon, variable in size, with a short neck. They may fill completely with contrast medium but sometimes only the peripheral area of the diverticulum is outlined by contrast medium because of the presence of faecal contents. →Double contrast barium study will better visualize small intramural diverticula and will in general display diverticula better because of more pronounced colon distension. →Deterioration of structural proteins in the colon wall may explain why diverticula of the colon are seen at a young age in patients with collagen diseases such as Ehlers Danlos syndrome and Marfan syndrome. ☉Meckel's diverticulum →Triad: hemorrhage, intestinal obstruction, diverticulitis →distal 100 cm of the ileum, omphalomesenteric duct, antimesenteric site →Bleeding: ulceration of the ileal mucosa adjacent to ectopic gastric mucosa located within the diverticulum. →50% of all lower gastrointestinal bleeding in children →Technetium-99m pertechnetate is normally taken by the ectopic gastric mucosa, providing the basis for the Meckel scan. ☉★Sigmoid Volvulus →abdominal pain, distension, and absolute constipation. →Predisposing factors include chronic constipation, megacolon, and an excessively mobile colon. →The key radiologic features are those of a double-loop obstruction, which has been reported in approximately 50% of patients. The key finding consists of a dilated loop of pelvic colon, associated with features of small bowel obstruction and retention of feces in an undistended proximal colon. →Single-contrast barium enema examination is adequate because the barium readily enters the empty rectum and usually encounters a complete stenosis, which is likened to a beak, the so-called ★bird's beak or bird-of-prey sign. →decompression and untwisting of the sigmoid loop may be achieved by the passage of a long soft tube through the obstruction, per rectum under fluoroscopic or endoscopic control. This procedure allows for rapid decompression of the distended colon, with the immediate relief of symptoms. ☉Carcinoid tumor →75% GI endocrine tumors, originate from Kulchitsky cells(appendix, ileum, rectum) →more malignant from small bowel, bronchus →carcinoid syndrome triad: cutaneous flushing, diarrhea, valvular heart dz →production of serotonin metabolite 5-HIAA in urine →octreotide scintigraphy identifies the site ☉Carcinoma of the Ampulla of Vater →The Courvoisier sign, painless jaundice associated with a palpable gallbladder, may be present. →Pancreatic cholera: Diarrhea is due to the absence of lipase within the gut caused by pancreatic duct obstruction. →Pancreaticoduodenectomy: the classic and standard resection procedure for ampullary carcinoma ●Plasty ☉Graft: no vessel FTSG: post-auricular, inguinal STSG: ☉Flap: vessel Random: no paticular vessel Axial: frontal, inguinal →myocutaneous: →Lattissmus Dorsi/ in breast /thoracodorsal a.（都是背部dorsi） →Pectoralis major/ thoracoacromial/axillary a. →Deltopectoris/ int. thoracic a. →Rectus abdominis/inf. epigastric a. →Tensor fascia lata in inguinal and buttock →Gracilis in perineum →Rectus femoris /in breast and lower abdomen →Gastrocnemius/sural a. Free: must Axial( not Random) ☉Facial fr. 1.Mandibular fr. 2.Maxillary fr. →LeFort I/II/III: transverse/ pyramidal/ craniofacial disjunction →Donkey-like face, CSF leak 3.Zygomatic fr. →trismus, antimongoloid slant（眼睛外側下斜）(lat. canthal lig.), malar anaesthesia(infraorbital n.) 4.Nasal bone fr. 5.Orbital blow-out fr. →diplopia, enophthalmos ☉Cleft lip →op timing: rule of ten (Age >10wk, BW >10 pound, Hct>10) (Cleft palate : 1-2 y/o) →Millard "rotation advancement flap method" ☉Rhytidectomy（拉皮術） The superficial fascia of the face and neck overlying the parotid and cheek area is referred to as the SMAS (ie, superficial muscular and aponeurotic system). This system has an extensive domain, with most authors acknowledging that the galea is its superior extension and the intermingling with the platysma its lower-most extension. ●Paediatric ☉Op timing →Polydactyly: 6-12 mo →Cryptorchidism: 1-2 y/o →Hypospadias: 1 y/o →Funnel chest: 3-4 y/o →Biliary atresia: <60 days ☉IVF post op: 100-120 ml/kg/day, 10% glucose + 1/4 NaCl(0.225%) ☉Inguinal Hernia: right（右側睪丸慢下）（慣用手是右手） Cryptochidism: right ☉Jejunoileal atresia →Apple-peel, Christmas tree deformity: Type IIIB →★String of sausage: Type IV →Mesenteric vasculopathy ☉Double bubble sign: congenital duodenal atresia（全部都double!!) Invertogram倒立腹臀部X光: imperforate anus ☉Esophageal atresia: 生下來一直流口水，必須立即放NG測試 ☉Infantile hypertrophic pyloric stenosis(IHPS) →Single bubble sign(bird beak,string) →good appetite, ★projectile vomiting →★Olive-like mass by palpation →Rammstedt's pyloromyotomy ☉Intussusception →6mo-2 y/o robust boy →leading point: diverticulum, polyps, tumor →intermittent pain, irritable cying, vominting, ★currant jelly stool →target sign, pseudokidney sign →barium enema reduction, < 24hr →manual ★milking from distal to proximal ☉Juvenile polyp →bright red bloody stool ☉Congenital diaphragmatic hernia 1.Posterolateral / Bochdalek 2.Substernal / Morgagni 3.Paraesophageal hiatal →GI obstruction →Pulmonary hypoplasia→PHTN→asphyxia ☉Poland's Syndrome →absence or hypoplasia of the pectoralis major and minor muscles, hypoplasia or absence of nipple and breast, hypoplasia of subcutaneous fat, absence of axillary hair, and partial absence of the upper costal cartilages and portions of ribs, usually the second, third, and fourth. →The absence of the sternal head of the pectoralis major muscle: minimal expression →Brachysyndactyly, ectrodactyly, and ectromelia ●Urology ☉Prostate McNeal's classification is based on histological landmarks. It consists of 3 distinct zones such as the central zone, transitional zone and the peripheral zone. BPH is more commonly seen in the transitional zone whereas prostatitis and prostate cancer occurs more commonly in the peripheral zone. （中間派自肥，失勢派反叛） ☉retrograde ejaculation →the part of the bladder that normally closes during ejaculation (the bladder neck) remains open, causing the ejaculatory fluid to travel backward into the bladder. Common causes of retrograde ejaculation include diabetes, spinal cord injuries, certain drugs, and some surgical operations (including major abdominal or pelvic surgery--one of the most common causes is transurethral resection of the prostate). ☉Extracorporeal Shock Wave Lithotripsy (ESWL) →Recommended for ureteral stones in the middle and upper third and renal stones measuring between 5 mm and 25 mm. →recommended therapy for 80% of all stones, because it is safe, quick, effective and non-invasive. →Lithotripsy works by focusing acoustic shock waves directly on the stone. Over the course of treatment, the stone disintegrates into very small sand-like particles, which are then discharged by normal peristalsis. →The effectiveness of ESWL depends largely on the composition and size of the stone, as well as the type of equipment used. For stones measuring < 2.5 cm, success rates are around 90%. →Absolute contraindications for ESWL are pregnancy, urinary tract infection, uncontrolled bleeding and hypertension. →Relative contraindications for ESWL are very large stones, severely dilated collecting systems, protein matrix stones, obese patients, and patients with pacemakers. ☉Ureteroscopy →Recommended for stones in the lower and middle third of the ureter. →Endoscopic retrieval involves retrograde visualization of the urinary tract through the urethra. Ancillary lithotripters (i.e. lasers, ultrasound, electrohydraulic) help break the stones into small pieces so that they can be retrieved mechanically. →This is an in-patient procedure performed under general anesthesia. Stone free rates using endoscopy are usually very good, but effectiveness depends largely on the experience of the operator. →Complications include inadvertent perforations, bleeding and stricture formation. ☉Percutaneous Nephrolithotomy (PCNL) →Recommended for large staghorn calculi鹿角形石頭, multiple renal stones, large lower pole kidney stones and calculus with associated renal outlet obstruction. →involves making a 1 cm opening to access the kidney. The kidney is perforated using an 18 gauge needle and then dilated to allow the use of a nephroscope to remove the offending stone(s). Generally, patients are hospitalized for several days and may have a nephrostomy tube left in the kidney during the healing process. →Stone free rates are very good, but complications exist and results vary depending on the experience of the operator. ☉Surgery →Recommended for patients with very large staghorn calculi and for some ureteral calculi. →Open surgery still has a role in stone management, especially for staghorn calculi and stones in the lower pole. Open surgery can be performed in virtually any part of the country while endoscopy and lithotripsy are confined to tertiary centers. Stone free rates are very good, but complications and morbidity rates are the highest, and recovery time is the longest. ☉bulbocavernous reflex: The glans penis or the clitoris squeezed, a gentle jerk on an indwelling catheter.... will contract the external anal sphincter and bulbocavernous muscle when the S2 to S4 reflex is intact. ☉Renal TX: Cyclosporine: inhibit IL-2 receptor gene(T4 cell) activation Azathioprine: BM suppression, inhibit megakaryocyte replication Prednisolone: inhibit cytokine gene expression OKT3: act on CD3 of all lymphocytes Rapamycin: 20% hyperlipidemis ☉Tx immunology: activation of recipient T cell 1.Donor MHC+ Donor peptide 2.Recipient MHC+ Donor peptide ☉Hypospadias →chordae向腹側彎，背側包皮如披風 1. first degree or glanular hypospadias: the meatus is at the level of the glans :60% 2. second degree, where the meatus is at the level of the penile shaft, either coronal (the base of the glans), subcoronal (below the base of the glans) or midpenile (in the middle of the shaft) 3. third degree, which includes a meatus opening on the scrotum or below, either a penoscrotal, scrotal or perineal hypospadias: voiding cystourethrogram (VCUG), IVU, bifid scrotum, penoscrotal transpostion, ambiguous genitals, undescended testis, chromosome anomaly ☉micturition 1. Detrusor: Beta stimulation, via fibers of the hypogastric nerve, suppress contraction of the detrusor. Conversely, parasympathetic stimulation, by fibers in the pelvic nerve, cause the detrusor to contract. Sympathetic stimulation is predominant during bladder filling, and the parasympathetic causes emptying. 2. Internal sphincter: alpha-adrenergic. Sympathetic stimulation of these alpha receptors, via fibers in the hypogastric nerve, contributes to urinary continence. 3. External sphincter: innervation from the pudendal nerve. During micturition, supraspinal centers block stimulation by the hypogastric and pudendal nerves. This relaxes the internal and external sphincters and removes the sympathetic inhibition of the parasympathetic receptors. ☉The TNM system stages RCC tumors at four intervals: Stage I Small tumors (less than 1 inch) without evidence of local invasion; no lymph node involvement and absence of distant disease Stage II Tumors larger than 1 inch without evidence of local invasion; no lymph node involvement and absence of distant disease Stage III Tumors of any size that involve one lymph node (less than 1 inch); tumors that invade the adrenal gland or surrounding renal tissues; tumors that invade the renal vein or the inferior vena cava Stage IV A mixed group including tumors that invade adjacent structures; any tumor that has evidence of distant spread; any tumor in which more than one lymph node is involved ☉Germ Cell Tumors →Seminoma, a GCT subtype: 1. 40 y/o, confined to the testes in about 70% of cases and metastasizes to the lymph nodes in about 25% of cases. Distant metastasis is present in 5% of cases at presentation. These testicular primary tumors are usually homogenous and large. 2. Spermatocytic seminoma, 60y/o. bilaterally more often than seminoma and is an indolent tumor that rarely metastasizes. →Nonseminomatous germ cell tumor (NSGCT) has the following forms: 1. Embryonal carcinoma: rapid and bulky growth and by spread via lymphatic and hematogenous routes to distant viscera (eg, lungs, liver). More than 60% of patients have metastases at the time of presentation. Pain is a common feature in these patients. 2. Teratoma is found commonly in residual or recurrent masses.★It is the least aggressive form, but approximately 30% of patients with clinical stage 1 disease have relapse after orchiectomy. 3. ★Choriocarcinoma is the most aggressive of the NSGCTs. It disseminates hematogenously to lungs, liver, brain, and other viscera very early in the disease process. 4. Yolk sac tumors typically present as a large primary tumor. →★Platium-based C/T ☉Prostate cancer →most peripheral zone ☉Urinoma →an encapsulated extrapelvocalyceal collection of urine that forms from urine leakage through a tear in the collecting system or the proximal ureter when ureteric obstruction is present. Accidental or surgical trauma, congenital obstruction in children, ureteric tumour, stone, blood clots, and periureteric fibrosis are among the usual causes of the obstruction as urine leaks into the perirenal space. ●Anaestheology ☉Cricoid pressure (Sellick's maneuver) :reduce the incidence of gastric insufflation and regurgitation during ventilation ☉ETT Cuff pressure< 25mmHg ☉Narrowest in children: cricoid ☉Allen's Test. 1. Instruct the patient to make a tight fist. If the patient is unresponsive raise the arm above the heart for several seconds to force blood to leave the hand. 2. Apply direct pressure on the radial and ulner arteries to obstruct blood flow to the hand as the patient opens and closes his fist rapidly. 3. Instruct the patient to open his hand, with the radial artery remaining compressed. If the patient is unresponsive, keep the arm above the heart level. 4. Examined the Palmer surface of the hand for an errythematous blush or pallor within 15 seconds. 5. A positive Allen's test is when a blush indicates ulnar patency. 6. A negative Allen's test, indicates occlusion of the ulner artery. This radial artery should not be punctured. ☉The primary dangers of nitrous inhalation are: Oxygen deprivation Frost bite Loss of motor control Vitamin B12 interference Folic acid interference Nausea ☉Inhalative Anaesthesia 1.Halothane: Br, arrhythmia, tremor post op, Hepatotoxicity, no atropine necessary 2.Enflurane: expensive, epilepsy 3.Isoflurane: most rapid onset and recovery, least tocixity, most expensive, coronary steal syndrome →→Muscle relaxation, MAC (minium alveolar conc.): Enflurane> Isoflurane > Halothane（還能說哈囉表示麻得不夠） →→CV stability: Isoflurane> Enflurane > Halothane （CK： isozyme） →→Solubility, Cerbral BF: Halothane > Enflurane > Isoflurane（與上組相反） ☉Factors affecting induction 1.high concentration 2.hyperventilation 3.low CO: 血液集中在central compartment包括CNS 4.low solubility ☉Succinylcholine: IOP↑ ☉IV Anaesthesia →→Two features are important in determining the onset and duration of action of these drugs: lipid solubility and redistribution of the drug. A. Barbiturates: Thiopental. (Chloride channel) →enhance porphyria, treat epilepsy →Being a very lipid soluble compound, thiopental has a rapid onset of action after IV administration (- 1 minute). The hypnotic action lasts a few minutes only. This ultra-short acting action is due to ★redistribution of the drug from brain to more slowly equilibrating tissues including muscle, splanchnic tissue. Both rapid onset and short duration of action are ideal for induction agents. →Metabolism of thiopental takes place in the liver slowly, and thiopental will accumulate in the tissues to a toxic level after repetitive administration. Thus, thiopental is not used for the duration of anesthesia by continuous infusion. Thiopental does not provide analgesic action. →injectable solution with a pH of 11. To avoid drug precipitation in the IV lines, it must not be coadministered with acidic solutions such as those containing opioids and muscle relaxants. B. Non-Barbiturate Hypnotics 1. Propofol (Milk of Anesthesia) →very hydrophobic nature, formulated in a solution with 10% Soya bean oil, 2.25% glycerol, and 1-2% egg phospholipids. →identical action to thiopental with a rapid onset of induction and short duration of action. Two advantages over thiopental: (1)Recovery from propofol anesthesia is more rapid and pleasant (less nausea and vomiting). (2)It can be used for long duration of anesthesia because propofol is rapidly metabolized in the liver by conjugation to glucuronide and sulfate and excreted in the urine. (Note that the short duration of action is due to ★redistribution of propofol and not due to its metabolism). As a result, propofol has superseded thiopental as an induction agent. 2. Etomidate →Causes rapid induction of anesthesia as propofol. Its side effects (involuntary movements during induction and high incidence of nausea, vomiting during recovery, and adrenocortical suppressions) diminish its popularity. →→Both barbiturates and non-barbiturates enhance the inhibitory responses by: (1)Directly activating the GABAA receptor to open the chloride channel in the absence of transmitter GABA . (2)Increasing the open time of the GABA activated receptor chloride channel. C. Benzodiazepines. →→amnesia without causing loss of consciousness. It enhances the inhibitory responses by acting on the GABAA receptor to increase the frequency of the chloride channel opening induced by GABA. 1. Midazolam →The onset of action is much slower than with other anesthetic induction agents, therefore it is not used as an induction agent. Midazolam has a shorter half-life (- 2 hrs.) than diazepam (- 30 hrs.) and is not converted to active metabolites. 2. Diazepam →dissolved with the aid of propylene glycol (antifreeze), is less popular than midazolam for IV use because it is painful at the injection site. Diazepam is given orally for premedication for anesthesia. Because the onset of action is slow and the metabolites are active, having a long half-time in the body, diazepam is not used as an induction agent but is useful in anesthesia as premedication. It can also be used as intraoperative sedation and with other drugs, as part of balanced anesthesia. 3. Flumazenil →antagonist of the benzodiazepine receptor and can be used to accelerate the recovery from depression due to benzodiazepine overdose. D. Ketamine. →resembles phencyclidine, which is a "street drug" with a pronounced effect on sensory perception. It produces dissociative anesthesia resulting in catatonia, amnesia, and analgesia. The patient may appear awake and reactive, but does not respond to sensory stimuli. →acts on the NMDA-receptor. It can be used as a general anesthetic agent for children. Because of the high incidence of post-operative psychic phenomena (sensory and perceptual illusion and vivid dreams) associated with its use, ketamine is not commonly used in adult patients. It is considered useful for high-risk geriatric patients and patients in shock, because of its cardiostimulatory properties. →Since an induction of anesthesia and analgesia can be achieved by the intramuscular administration of ketamine, it is useful in anesthetizing children. It also has a great value in developing countries and in war zones where anesthesia equipment is not readily available. E. Opioids: Meperidone, Morphine, Methadone, Fentanyl →frequently used as premedicant drugs before anesthesia and surgery because of their sedative, anxiolytic, and analgesic properties. The opioids of the fentanyl family, when intravenously applied continuously in large doses, are used as primary anesthetic agents. Fentanyl and sufentanil are highly potent phenylpiperidine derivatives, with actions similar to morphine, but short acting - particularly sufentanil. It is particularly useful in patients undergoing cardiac surgery and other high-risk surgery because the opioids have minimal effect on the cardiovascular system. →direct action on the opioid receptor in the spinal cord, opioids (e.g., morphine) are most frequently used by the epidural route to achieve spinal anesthesia. →The side effects include respiratory depression, pruritus, and nausea and vomiting. Since the respiratory depressant effect occurs at therapeutic doses, is the most common cause of death in acute opioid poisoning. Naloxone, an opioid receptor antagonist, is used to treat respiratory depression caused by opioid overdose. ☉Opioid receptors →Various opioid receptors exist in the mammalian CNS, namely mu, kappa, sigma, delta, and epsilon. These receptors are located in the brain (mostly in the periaqueductal grey), spinal cord, peripheral nerves, adrenal medulla, ganglia, and gut. →Stimulation of mu and sigma receptors produces intense feelings of well being and euphoria. Kappa-receptor stimulation produces dysphoria. Antagonism at these receptors may produce dysphoria, but not consistently. Antagonists block euphoria produced by opioids. Endogenous opioids, though not highly selective, have a preference for specific receptor types. Beta-endorphin is an endogenous ligand for the mu-receptor; enkephalins and dynorphins have an affinity for sigma- and kappa-receptors, respectively. The dopaminergic mesolimbic system, which originates in the ventral tegmental area (VTA) of the midbrain and projects to the nucleus accumbens, is crucial in (1) the reward effects of intracranial self-stimulation, (2) the natural rewards of water and food intake, and (3) the action of abusive drugs, including opioids. →Basal activity of this system, expressed in dopamine release in the nucleus accumbens, is under the tonic control of 2 opposing opioid systems, activation of mu- and sigma-receptors increases, while kappa-receptor activation decreases, the basal activity of the mesolimbic system. Experimental evidence with laboratory animals supports the idea that manipulation of these receptors with opioids and other substances of abuse (as well as electrical stimulation) affects self-administering behavior. These reward pathways are thought to have evolved for the natural rewards such as food and water intake ☉core BT: esophagus lower part ☉local: 1.pKa↓(pH:7.4),onset↑ 2.liposolubility↑, potency↑ 3.protein binding ability↑ ☉Train of four: muscle recovery > 0.8 ☉Gate theory: Ad fiber inhibit C fiber ☉NSAID: not include acetaminophen 1.Indemethacin 2.Naproxen 3.Ibuprofen 4.Aspirin 5.Tilcotil 6.Feldene ☉Local: 1.Ester常有過敏: procaine, tetracaine, chloroprocaine （都有R） 2.Amides少見過敏: lidocaine(Safest!!), bupivacaine, prilocaine, etilocaine, mepivacaine ☉Intrathecal morphine: 0.2-1 mg ☉Malignant Hyperthermia: HR↑BT↑Rigidty↑Acidosis, CO2↑, K↑, CK↑, LDH↑, Lactate↑ |