Laryngeal Mask Airway (LMA) Insertion Technique

[postlink]http://tube.medchrome.com/2013/05/laryngeal-mask-airway-lma-insertion.html[/postlink]

[starttext]Originally designed for use in spontaneously breathing patients, it consists of a ‘mask’ that sits over the laryngeal opening, attached to which is a tube that protrudes from the mouth and connects directly to the anaesthetic breathing system. On the perimeter of the mask is an inflatable cuff that creates a seal and helps to stabilize it.

The use of the laryngeal mask overcomes some of the problems of the simple adjuncts:

1. It is not affected by the shape of the patient’s face or the absence of teeth.
2. The anaesthetist is not required to hold it in position, avoiding fatigue and allowing any other problems to be dealt with.
3. It significantly reduces the risk of aspiration of regurgitated gastric contents, but does not eliminate it completely.

Relative contraindication: 

1. Increased risk of regurgitation, for example in emergency cases, pregnancy and patients with a hiatus hernia. 

Technique for insertion of the standard LMA:

1. The patient’s reflexes must be suppressed to a level similar to that required for the insertion of an oropharyngeal airway to prevent coughing or laryngospasm.
2. The cuff is deflated and the mask lightly lubricated.
3. A head tilt is performed, the patient’s mouth opened fully and the tip of the mask inserted along the hard palate with the open side facing but not touching the tongue.
4. The mask is further inserted, using the index finger to provide support for the tube.
5. Eventually, resistance will be felt at the point where the tip of the mask lies at the upper oesophageal sphincter.
6. The cuff is now fully inflated using an air-filled syringe attached to the valve at the end of the pilot tube.
7. The laryngeal mask is secured either by a length of bandage or adhesive strapping attached to the protruding tube.
8. A ‘bite block’ may be inserted to reduce the risk of damage to the LMA at recovery.

[endtext] http://www.youtube.com/watch?v=rnTLqhd6cwkendofvid

Laryngeal Mask Airway (LMA) Insertion Technique

Classification of Seizure

[postlink]http://tube.medchrome.com/2013/05/classification-of-seizure.html[/postlink]

[starttext] [endtext]Seizure is any clinical event caused by an abnormal electrical discharge in the brain, whilst epilepsy is the tendency to have recurrent seizures.

Classification:

A. Partial seizure: Focal, only part of cortex involved

1. Simple: No loss of consciousness (LOC), no postictal state
2. Complex: Postictal state present, LOC may or may not be present

B. Generalized seizure: Always associated with LOC, whole cortex is involved

1. Absence (petit mal): Brief episode of nonresponsiveness to external or internal stimuli; motor tone is preserved
2. Tonic–clonic (grand mal): Generalized convulsion - brief tonic phase (stiffening) followed by clonic phase (rhythmic jerking) 

http://www.youtube.com/watch?v=6zXFUIjY5xUendofvid

Classification of Seizure

Intubation procedure: Video

[postlink]http://tube.medchrome.com/2013/01/intubation-procedure-video.html[/postlink]

[starttext]Indications:
1. Maintenance of a patent airway:

• When an awkward intraoperative position is required (eg. lateral decubitus, prone, sitting)
• When the airway is inaccessible (eg. during head and neck operations)
• When difficulties with the face mask are anticipated (eg. in grossly obese or edentulous patients or those with unusual facial features).

2. Protection of the airway: from contamination by blood, pus, debris, or stomach contents

3. Controlled ventilation

Technique of laryngoscopy and Tracheal intubation:

1. Position: The patient is positioned supine with the head resting on a pillow, in the so-called 'sniffing the morning air position' (flexion of the lower cervical spine and extension of head at atlanto-occipital junction). The position aligns the oral, pharyngeal and laryngeal axis so that the pathway from the lips to the glottis is nearly a straight line.

2. Laryngoscopy: The laryngoscope is held in the left hand, whilst the right hand is used to stabilize the head and open the mouth. The laryngoscope is inserted into the right side of the patient's mouth avoiding the incisor teeth and pushing the tongue to the left. The tip of the blade is advanced in the midline over the back of the tongue until the epiglottis comes into view. The tip of Macintosh laryngoscope blade should be positioned above the epiglottis, into the vallecula (the space between the base of tongue and the epiglottis). The tongue and pharyngeal soft tissues are then lifted, pulling the epiglottis up without directly touching it, exposing the glottic opening. You should use your arm and shoulder to lift the laryngoscope handle in an anterior and forward direction (along the long axis of handle containing the batteries). The tendency to lever the laryngoscope against the upper incisor teeth or upper gum should be avoided to prevent trauma.

The Miller blade, which is straight, is less commonly used. The tip of Miller blade is passed beneath the laryngeal surface of the epiglottis and the epiglottis itself is then lifted to expose the vocal cords. There is more risk of trauma to the epiglottis and stimulation of the laryngeal surface of the epiglottis.

3. Intubation: The size of the tracheal tube used depends on the patient's age and body build. Usually an 8mm internal diameter cuffed tube is used for women and a 9mm tube for men. The tube is held in the right hand as one would hold a pencil and advanced through the oral cavity through the right corner of the mouth and then through the vocal cords. External pressure on the cricoid or thyroid cartilage may be required to help visualize the laryngeal inlet. The proximal end of the tube cuff is placed so that the cuff is below the vocal cords, and the length markings on the tube are noted in relation to the patient's lips. The cuff is inflated to obtain a seal in the presence of 20-30 cm H20 pressure of gas in the breathing system.

4. Verification of position of tube: The next step is to verify the position of the tracheal tube. The best method to determine the position of the tube is by detection of carbon dioxide in expired gas. It is possible for gas in the stomach to contain carbon dioxide but this will only be present in the first few 'breaths'. Visulaization of the end of the tube advancing through the vocal cords is also taken as a sign of correct palcement. However, tubes may be displaced after 'correct' insertion. Auscultation of both lung fields in the axilla and over the stomach may also be used to confirm correct placement, but is less reliable. Asymmetrical breath sounds may indicate that the tip of the tube lies in one or other of the main bronchi (usually the right_. The tube should be withdrawn until breath sounds are heard bilaterally.

Complications of orotracheal intubation include:

• Injury to lips, tongue or teeth
• Injury to larynx (especially the arytenoid cartilages and the vocal cords)
• Tracheal mucosa tear
• Sympathetic stimulation

Attempting laryngoscopy or tracheal intubation in lightly anesthetized patients who are not fully relaxed can result in laryngospasm, coughing and bronchospasm. The laryngoscope should be removed, face-mask ventilation should be continued and anesthesia deepened or more muscle relaxant given to achieve adequate conditions. A peripheral nerve stimulator can be used to ensure complete neuromuscular blockade before commencing laryngoscopy and intubation.[endtext]
http://www.youtube.com/watch?v=BRjN3kQZLRIendofvid

Intubation procedure: Video

Brushing technique: Bass and Modified Bass Methods

[postlink]http://tube.medchrome.com/2013/04/brushing-technique-bass-and-modified.html[/postlink]

[starttext]There are 5 commonly used brushing techniques: Bass or modified bass, Charters, Modified Stillman, Rolling stroke and Modified stroke. While the rolling technique is commonly used by the children, Bass or modified bass is the commonest technique for the adults. 

Bass: 

1. Hold the toothbrush sideways against your teeth with some of the bristles touching your gums.
2. Tilt the brush so the bristles are at 45 degree angle and pointing at your gum line.
3. Move the brush back and forth, using short strokes. The tips of the bristles should stay in one place, but the head of the brush should wiggle back and forth. You also can make tiny circles with the brush. This allows the bristles to slide gently under the gum. Do this for about 20 strokes or 20 circles. 
4. Repeat for every tooth, on the insides and outsides.
5. The toe bristles of the brush can be used to clean the lingual (tongue) surface of the anterior teeth.

Modified Bass:

1. Follow all the steps of the Bass technique.
2. After the vibratory motion has been completed in each area, sweep the bristles over the crown of the tooth, toward biting surface of the tooth.

Importance of these methods:

1. Most effective in cleaning cervical 1/3 & beneath gingival margins
2. Suitable for everyone – Periodontally healthy & periodontally disease
3. Periodontal maintenance
4. Cleanses sulcus (space between tooth and gums)[endtext] http://www.youtube.com/watch?v=LqCpZm6s_dEendofvid

Brushing technique: Bass and Modified Bass Methods

Inferior Alveolar Nerve Block: Anatomical consideration and Technique

[postlink]http://tube.medchrome.com/2013/04/inferior-alveolar-nerve-block.html[/postlink]

[starttext]Inferior Alveolar Nerve Block (IANB) is a technique for dental anesthesia used to produce anesthesia of the mandibular teeth, gingival tissues of the mandible and the lower lip.


Nerves Anesthetized

• Inferior alveolar (CN V3 branch)
• Incisive
• Mental
• Lingual

Areas Anesthetized

1. Mandibular teeth to the midline
2. Body of the mandible, inferior portion of the ramus
3. Buccal mucoperiosteum, mucous membrane anterior to the mental foramen (mental nerve)
4. Anterior two thirds of the tongue and floor of the oral cavity (lingual nerve)
5. Lingual soft tissues and periosteum (lingual nerve)

Indications

1. Procedures on multiple mandibular teeth in one quadrant
2. When buccal soft tissue anesthesia (anterior to the mental foramen) is necessary
3. When lingual soft tissue anesthesia is necessary

Contraindications

1. Infection or acute inflammation in the area of injection (rare)
2. Patients who are more likely to bite their lip or tongue, for instance, a very young child or a physically or mentally handicapped adult or child

Advantages

• One injection provides a wide area of anesthesia (useful for quadrant dentistry).

Disadvantages

• Wide area of anesthesia (not indicated for localized procedures)
• Rate of inadequate anesthesia (31% to 81%)
• Intraoral landmarks not consistently reliable
• Positive aspiration (10% to 15%, highest of all intraoral injection techniques)
• Lingual and lower lip anesthesia, discomfiting to many patients and possibly dangerous (self-inflicted soft tissue trauma) for certain individuals
• Partial anesthesia possible where a bifid inferior alveolar nerve and bifid mandibular canals are present; cross-innervation in lower anterior region

Symptoms

1. Tingling or numbness of the lower lip (mental nerve)
2. Tingling or numbness of the tongue (lingual nerve)

Signs

1. Using an electrical pulp tester (EPT) and eliciting no response to maximal output (80/80) on two consecutive tests at least 2 minutes apart serves as a “guarantee” of successful pulpal anesthesia in nonpulpitic teeth. 
2. No pain is felt during dental therapy.

Precautions

1. Do not deposit local anesthetic if bone is not contacted. The needle tip may be resting within the parotid gland near the facial nerve (cranial nerve VII), and a transient blockade (paralysis) of the facial nerve may develop if local anesthetic solution is deposited.
2. Avoid pain by not contacting bone too forcefully.

Text from: Handbook of Local Anesthesia (Malamed)
[endtext] http://www.youtube.com/watch?v=39kPPBbrM1cendofvid

Inferior Alveolar Nerve Block: Anatomical consideration and Technique

Stages and process of Wound healing

[postlink]http://tube.medchrome.com/2013/04/stages-and-process-of-wound-healing.html[/postlink]

[starttext]

1. Haemostasis (immediate): In response to exposed collagen, platelets aggregate at the wound and degranulate, releasing inflammatory mediators. Clotting and complement cascades activated. Thrombus formation and reactive vasospasm achieve haemostasis

2. Inflammation (0-3 days): Vasodilatation and increased capillary permeability allow inflammatory cells to enter wound, and cause swelling. Neutrophils amplify inflammatory response by release of cytokines; reduce infection by bacterial killing; and debride damaged tissue. Macrophages follow and secrete cytokines, growth factors, and collagenases. They phagocytose bacteria and dead tissue and orchestrate fibroblast migration, proliferation, and collagen production.

3. Proliferation (3 days-3 weeks): Fibroblasts migrate into the wound and synthesize collagen. Specialized myofibroblasts containing actin cause wound contraction. Angiogenesis is stimulated by hypoxia and cytokines and granulation tissue forms

4. Remodelling (3 weeks-1 year): Re-orientation and maturation of collagen fibres increases wound strength.

Text taken from Oxford Handbook of Clinical Surgery

Points to remember:
Maximum collagen production occurs at 20 days
Maximum wound strength at 3 to 6 months

[endtext]  http://www.youtube.com/watch?v=u7Ryg9nVFLIendofvid

Stages and process of Wound healing

Stages of fracture healing

[postlink]http://tube.medchrome.com/2013/04/stages-of-fracture-healing.html[/postlink]

[starttext]

1. Inflammation: Bleeding from fracture site and surrounding soft tissues creates a hematoma, which provides a source of hematopoietic cells capable of secreting growth factors. Subsequently fibroblasts, mesenchymal cells, and osteoprogenitor cells are present at the fracture site, and granulation tissue forms around the fracture ends. Osteoblasts, from surrounding osteogenic precursor cells, fibroblasts, or both proliferate.

2. Repair: Primary callus response occurs within 2 weeks. If the bone ends are not in continuity, bridging (soft) callus occurs. The soft callus later is replaced, via the process of enchondral ossification, by woven bone (hard callus). Another type of callus, medullary callus, supplements the bridging callus, although it forms more slowly and occurs later. The amount of callus formation is indirectly proportional to the amount of immobilization of fracture.

3. Remodeling: This process begins during the middle of the repair phase and continues long after the fracture has clinically healed (upto 7 years). Remodeling allows the bone to assume its normal configuration and shape based on the stresses to which it is exposed (Wolff's law). Throughout the process, woven bone formed during the repair phase is replaced with lamellar bone.

Text source: Miller Review of Orthopaedics
[endtext]

http://www.youtube.com/watch?v=VZF3xicLtTwendofvid

Stages of fracture healing

Outbreak Investigation Basics

[postlink]http://tube.medchrome.com/2013/02/outbreak-investigation-basics.html[/postlink]

[starttext]Epidemic or outbreak is a significant rise of level of disease above the normal endemic level (expected level of disease in community). The steps in outbreak investigation are:

1. Prepare for fieldwork in advance: Literature review, decide role, team, equipments

2. Establish the existence of an outbreak:

• Compare with previous weeks, months or years of same geographic area and time period
• Excess may not be outbreak. It may be due to population change, media attention, improved screening, change in case definition, etc.

3. Verify the diagnosis, if possible

4. Define, identify and collect data on all cases

a. Case definition:

• Must include personal information, place information, time information and clinical information
• Types:

• Possible (Suspected): Broadest definition

• Probable

• Confirmed (Definite): Tightest definition (A clinically compatible case that is not laboratory confirmed and is not epidemiologically linked to laboratory-confirmed cases)

• Broad definition is needed in the beginning, so that cases aren't missed. It can be tightened later.

b. Identify all possible cases: surveillance data

c. Collect data on all possible cases: in relation to person, place, time and clinical features

5. Perform descriptive epidemiology

• Person
• Place (Spot map)
• Time (Epidemic curve)

6. Develop a hypothesis

• Include: What is known about likely pathogen, who is at risk, likely exposures, mode of transmission
• Should be testable

7. Evaluate hypothesis

• Comparative method: all cases having same symptoms, lab confirmation, etc.
• Analytic method: attack rates, case fatality rates, relative risks, odds ratio, statistical significance testing (chi-square, p-value)

8. Refine hypothesis and execute additional studies if required

9. Immplement control and prevention measures

10. Communicate findings and prepare a report

A very good pictorial guide: http://dse.healthrepository.org/bitstream/123456789/80/1/Obi%20Guide.jpg

Some terms:

• Index case: First person to come to attention to public health authorities
• Primary case: Acquiring disease from an exposure
• Secondary case: Acquiring disease from exposure to primary case

[endtext]
http://www.youtube.com/watch?v=ug_JVEEV_TMendofvid

Outbreak Investigation Basics

Physiology and Effects of Alcohol on Brain

[postlink]http://tube.medchrome.com/2013/02/physiology-and-effects-of-alcohol-on.html[/postlink]

[starttext]Alcohol can be regarded as a drug as it can cause physiologic addiction in all who consume it and may result in intoxication, tolerance or withdrawal.

Absorption and Elimination of alcohol:

1. 20% in stomach and 80% in small intestine
2. Can be detected in blood within 2-3 minutes of swallowing a few sips of whisky or beer
3. A single bolus of alcohol taken into an empty stomach will be completely absorbed into portal bloodstream within 30-90 minutes
4. As soon as alcohol enters the bloodstream, liver and kidneys will begin to eliminate
5. 90% is eliminated by liver and 10% by kidneys, sweat and breath
6. Chronic alcoholics with induced liver Cyt. P450 (until their liver fails) can metabolize alcohol at an abnormally high rate
7. Normal rate of elimination for non-alcoholic: 10 to 25 mg/100ml/hr

Blood Alcohol Concentration (BAC): BAC expressed as mg/dl or mg% is the most useful measurement of alcohol, because the rapid equilibrtion of alcohol across Blood brain barrier (BBB) means that BAC reflects the concentration of alcohol currently affecting the brain.

Mathematically, BAC = Total amount of alcohol in body/ Total amount of body water

The factors increasing BAC are:

1. Decreased body water

• Low body weight
• Appreciable adiposity
• Female gender

2. Faster absorption

• Rapid drinking
• Empty stomach

• Food physically obstructs the contact of alcohol molecules with gastric mucosa

• Food delays emptying through the pylorus

• Optimum concentration of alcohol (around 20%)

• Week drinks like beer have poor absorption

• Strong spirits (>40% concentration) irritate gastric mucosa resulting in excess secretion of mucus (barrier), cause pyloric spasm and reduce gastric motility

• Gastrectomy, Gastrojejunostomy

Effects of Alcohol on Brain:

Alcohol depresses the nervous system and any apparent initial excitant effect is due to suppression of inhibition by the cerebral cortex. It begins to act at lowest concentration upon the higher centers and it affect the lower centers of CNS only when BAC becomes higher. The correlation of BAC and physiologic effects have been correlated below:

• 0 to 50 mg%: No significant effect or mild euphoria
• 50 to 100 mg% (Cerebral cortex): Talkativeness, More self confidence, Reduced social inhibitions, Slight sensory disturbance, Poor judgement
• 100 to 150 mg% (Limbic system): Exaggerated emotions and memory loss
• 150 to 300 mg% (Cerebellum): Incoordination, unsteadiness, slurred speech, ataxia (Obvious drunkenness)
• 300 to 400 mg+ % (Hypothalamus and Medulla): Stupor, Increased BP, Decreased temperature, Bradycardia, Respiratory depression, Coma, Death 

A person is likely to appear more uninhibited in a student party than in a very formal function given the same level of alcohol.
[endtext]

http://www.youtube.com/watch?v=zXjANz9r5F0endofvid

Physiology and Effects of Alcohol on Brain

Postmortem brain dissection (Autopsy)

[postlink]http://tube.medchrome.com/2013/02/postmortem-brain-dissection-autopsy.html[/postlink]

[starttext]A. Opening the Skull:

1. Separate the hair and incise the scalp across the vertex from one mastoid process just behind the ear to another.
2. Reflect the scalp forwards and backwards past the hairline. Note injury to skull or deeper tissues of scalp.
3. Cut temporalis and masseter muscles on either side.
4. Cut the calvarium with the saw in a slightly "V" shaped fashion. Remove the skull cap by inserting and twisting chisel at the sawline.
5. Examine meninges and note extradural or subdural hemorrhage if any.

B. Removing the Brain:

1. Open superior longitudinal sinus. Examine for antemortem thrombus.
2. Cut dura along the sawline of skull and reflect towards the midline. Inspect the surface of brain.
3. Retract the frontal poles and cut anterior attachments of falx cerebri (i.e cribiform plate).
4. Elevate olfactory bulbs by inserting fingers between the frontal lobes and skull and drawing them backwards, retract the brain and cut: optic nerves, carotid arteries and other nerves.
5. Retract brain medially and cut tentorial attachments along the petrous ridges.
6. Retract brain posteriorly and cut remaining cranial nerves as close to bone as possible, vertebral arteries and spinal cord as distally as possible within the spinal canal.
7. Retract cerebellum and brainstem. Support brain and cut remaining dural attachment with scissors. Remove the brain from the cranial vault.

C. Dissecting the brain:

1. Brain can be fixed in 10% formalin to dissect later or it can be dissected at the moment.
2. Remove brainstem and cerebellum by thin knife section across the the cerebral peduncle in a planes perpendicular to the brainstem and aqueduct. 
3. Perform serial cross-section of the brainstem along the same plane and inspect for substantia nigra in medulla.
4. Cerebellum may be sectioned in a plane parallel to the long axis of brainstem. Observe the vermis and dentate nucleus.
5. Carefully inspect for surface vessels, cranial nerves, midline structures i.e. cingulate gyri, unci, mammilary body, pineal recess and the remaining part of brainstem.
6. Use serial coronal section at about 1 cm interval for the dissection of cerebral hemispheres. Examine the corpus callosum, thalamus, internal capsule and basal nuclei.

[endtext]

http://www.youtube.com/watch?v=Otq74eW4ouEendofvid

Postmortem brain dissection (Autopsy)

Postmortem Dissection of Heart (Autopsy)

[postlink]http://tube.medchrome.com/2013/02/postmortem-dissection-of-heart-autopsy.html[/postlink]

[starttext]A. Removal of Heart from the Body:

• Check the pericardium, open it and explore the pericardial cavity.
• Check the anatomy of great arteries before transecting them about 3 cm above the aortic and pulmonary valves.
• Check and transect the pulmonary veins. Transect the superior venacava about 2cm above the junction of the crest of right atrial appendage and superior venacava (to preserve the sinus node). Transect the inferior venacava close to the diaphragm.
• Remove the heart from the body.

B. Evaluation of coronary arteries:

Before beginning the dissection of heart, serial transverse transection at about 3mm intervals along the course of the main coronary arteries i.e. Left anterior descending artery, Right coronary artery and Left circumflex artery is performed using scalpel to visualize their patency. The obstruction of the coronary arteries can range from mild/grade I (>25%) to severe (70%) to critical/grade IV (>90%).

C. Dissection of Heart:

Many older methods (4 chamber method, Long axis method, Base of heart method, Window method, etc.) are impractical for routine diagnostic pathology. Only the inflow-outflow and short-axis (bread-slice) methods have withstood the test of time. Here we describe, the inflow-outflow method in which the heart is opened according to the direction of blood flow:

1. Right:

• Open right atrium using scissors, from the inferior venacava (IVC) to the right atrial appendage. Spare superior venacava and SA node. Examine the atrial cavity and septum along with the atrioventricular valves.
• Both the inflow and outflow cuts for the right ventricle are made about 0.5 cm from the ventricular septum, with either scissors or a knife from the right atrium to the ventricular apex through the tricuspid valve and then from apex to the pulmonary artery.

2. Left:

• Open left atrium from a point between the right upper and lower pulmonary vein orifices to the tip of left atrial appendage.
• In contrast to the right ventricle, the left ventricular inflow tract is opened not along the septum but rather along lateral wall between the mitral papillary muscles from the left atrium to the left ventricular apex.
• From the left ventricular apex to the aortic valve, the outflow cut follows the junction, generally forming a gentle inverted S-shaped cut.

A combined approach of Inflow-outflow method and short-axis method can also be used as it allows for examination of infarcts along with ventricular chambers.

D. Measurements:

• Total heart weight: 200gm-450gm normally (average 300 gm)
• Circumference of atrioventricular valves (before opening ventricles): Normally, tricuspid valve admits 3 fingers and mitral valve admits 2 fingers
• Wall thickness: Ventricles and septum (Thickness of normal left ventricle and right ventricle is less than 1.5 cm and 0.5 cm respectively). Wall thickness is measured at the level of papillary muscles.

[endtext]

http://www.youtube.com/watch?v=FRAZza4mtm4endofvid

Postmortem Dissection of Heart (Autopsy)

Urethral (Foley) Catheterization Procedure Video

[postlink]http://tube.medchrome.com/2012/11/urethral-foley-catheterization.html[/postlink]

[starttext]Indications for Foley catheter:

Diagnostic:

1. Monitoring of urinary output to assess volume status and renal perfusion
2. To collect uncontaminated urine specimen
3. Instilling contrast material into the bladder for cystourethrography

Therapeutic:

1. Acute or Chronic urinary retention
2. To increase the space in pelvic cavity to prevent damage to bladder during abdominal or pelvic surgery
3. Incontinence
4. Chronically bed-ridden patient for hygiene

Contraindications for Foley catheter:

• Urethral injury: Trauma patients with blood at meatus or abnormal prostate location on rectal exam. 

Equipments required:

1. Foley catheter (Size: 16-18 F for adults, 5-12 F for children). Coudé catheter (with curved tip that makes it easier to pass through the curvature of the prostatic urethra) must be used in cases of enlarged prostate.
2. Dressing/catheter pack containing drapes
3. Cleansing solution (Povidone)
4. Gloves
5. Lignocaine gel
6. Gauze swabs
7. Drainage bag
8. 50mL bladder syringe

Preparation for catheterization:

1. Position: Male (Supine position) and Female (Dorsal recumbent position - supine with knees flexed and heels held apart or Sims position - side lying with upper leg flexed at knee and hip)
2. Expose the genital area, prepare sterile field, drape the patient
3. Apply sterile gloves after cleaning the hands
4. Apply the lubricant to distal portion of catheter

Male Catheterization:

1. Pick up the glans penis with your non-dominant hand "dirty hand", through the hole in the drape: the other hand will be your "clean hand".
2. Holding a swab soaked in sterile saline with your clean hand retract the foreskin and clean the urethral orifice and glans thoroughly, so that your gloved fingers only touch the swab not the glans penis.
3. Without letting go of the penis, discard the swab and pick up the sterile lignocaine gel with your clean hand and inject into the urethra.
4. Still holding the penis in a vertical position (right angle) introduce the catheter with the clean hand and advance gently for approximately 10cm.
5. Lower the penis to lie horizontally and advance the catheter fully (through the prostatic urethra) up to the hilt.
6. Inflate the balloon now in the bladder via the smaller catheter channel with the 10mL sterile water.

Female Catheterization:

1. A similar technique is employed here to male catheterization, but note:
2. Separate the labia minora with the left hand and ensure the whole genital area is adequately cleaned using the right hand.
3. Identify the external urethral orifice. If this proves difficult in obese patients, an assistant may help by retracting the dependent fat from the pubic area.
4. Lubricate the tip of the catheter with sterile water or lignocaine gel and pass gently into the urethra.

Tips and problems 

No urine immediately: The bladder has just been emptied: insert a 2mL syringe into the end of the catheter and aspirate any residual urine.The catheter tip may be blocked with lignocaine gel-try gently instilling 15-20mL of sterile water and gently aspirating. 

Still no urine: The patient may be anuric or a false passage may have been created. Palpate to see if the bladder is empty or if you can feel the catheter balloon (which should not normally be palpable). Treat anuria appropriately. Consult a senior colleague if a false passage may have been created. 

Inability to insert: Try a smaller catheter or a silastic (firmer). If unsuccessful, ask a senior for help; suprapubic catheterization may be needed. 

Decompression of grossly distended bladder:  Rapid decompression of a distended bladder (e.g. from chronic retention) may result in mucosal haemorrhage. Empty the bladder by 250-500mL every 30min until empty. Then monitor urine output closely, as a brisk diuresis and dehydration may follow. 

Bypassing catheter: Usually due to catheter blockage. Check urine output, flush the catheter, and observe. If urine is flowing down the catheter and bypassing it, the catheter may be too small-try a slightly larger size.  

Catheter stops draining: The catheter may be blocked. Flush as above. If unsuccessful, try inserting a new catheter. Is the patient oliguric or anuric? Treat appropriately. 

Tips specific for Males: Never inflate the balloon until the catheter is fully inserted as this risks inflating the balloon within the prostatic urethera, causing urethral rupture: ideally you should see urine before inflating the balloon. Replace the foreskin to avoid paraphimosis. 

Tips specific for Females: Difficulty identifying urethral orifice. After warning the patient, place an index finger in the vagina to elevate the anterior vulva. Guide the catheter along the finger into the urethra.

Complications of Urethral catheterization:

1. Damage to the lining of urethra. Repeated trauma may lead to urethral stricture.
2. Rupture of urethra and Bleeding from urethra, prostate or bladder.
3. Urinary tract infection (UTI) and Septicemia.
4. Epididymitis.
5. Obstruction of catheter leading to backflow of urine which may cause renal damage

[endtext]

http://www.youtube.com/watch?v=o0DoftBJ1ewendofvid 

Urethral (Foley) Catheterization Procedure Video

Examination of Peripheral Pulses

[postlink]http://tube.medchrome.com/2012/10/examination-of-peripheral-pulses.html[/postlink]

[starttext]

Pulse: Alternate expansion and recoil of the arterial wall imparted by the column of blood due to pressure changes during ventricular systole and diastole.

Radial pulse:

• Wrist held in semiflexed and semipronated position
• Pulp of 3 fingers (index, middle, ring) over wrist
• Index (disal) finger obliterates artery
• Middle finger feels pulse
• Ring (proximal) finger applies pressure
• To feel collapsing pulse: raise the arm while feeling across the pulse with the fingers of other hand
• Note: Rate, rhythm, Condition of the arterial wall, Radioradial delay

Brachial pulse:

• Feel with thumb (right thumb for right arm and vice versa) with other fingers cupping round the back of elbow
• Medial to tendon of biceps
• Usually examined during BP measurement

Carotid pulse:

• Feel with left thumb for right artery and vice versa, one at a time
• Between larynx and anterior border of sternocleidomastoid
• Auscultate for bruits
• Usually examined during auscultation of heart sound
• Note: Volume, Character

Femoral pulse:

• With 2 fingers (index and middle)
• Midinguinal point (Medial to lateral : VAN)
• Usually examined during drawing of blood from femoral vein
• Note: Radiofemoral delay

Popliteal artery:

• With thumbs in front and fingertips behind, having curled both hands into the popliteal fossa
• Feel for the pulse in midline 3-4 cm below the knee crease
• Knee flexed 30 degree

Posterior tibial artery:

• 2cm below and posterior to medial malleolus

Dorsalis pedis artery:

• Feel in the middle of the dorsum of the foot just lateral to the tendon of extensor hallucis longus
• Best felt at the proximal extent of the groove between the 1st and 2nd metatarsals
• Continuation of anterior tibial artery

Recording of individual pulses:
a. Normal : +
b. Reduced: +/-
c. Absent: -
d. Aneurysmal: ++

[endtext]

http://www.youtube.com/watch?v=XHWOma466lcendofvid 

Examination of Peripheral Pulses

Episiotomy: Indications and Procedure video

[postlink]http://tube.medchrome.com/2012/07/starttext-episiotomy-or-perineotomy-is.html[/postlink]

[starttext]Episiotomy or Perineotomy is a surgical cut equivalent to the second degree perineal tear, made at the opening of the vagina during second stage of labour, to aid delivery and prevent rupture perineum and the surrounding tissues.

Indications:

• Maternal or fetal distress
• Premature baby or Breech presentation
• Large fetus
• Instrumental delivery is indicated
• Mother is too tired and unable to push
• Existing trauma to the perineum

Advantage of episiotomy over perineal tear:
Clean incision is easier to repair than a jagged tear and may heal faster

Procedure:

1. Local anesthetic is given (B)
2. Perineum is cut in angle with scissor (C). 2 types:

• Medio-lateral: The incision is made downward and outward from midpoint of fourchette either to right or left. It is directed diagonally in straight line which runs about 2.5 cm away from the anus (midpoint between anus and ischial tuberosity).
• Median: The incision commences from centre of the fourchette and extends on posterior side along midline for 2.5 cm. The disadvantage is that it may extend to involve the anal sphincter.

3. After delivery, the layers of muscle and skin are repaired with absorbable suture (D and E).

Complications:

1. Bleeding
2. Infection
3. Swelling
4. Defects in wound closure
5. Local pain
6. Urinary incontinence
7. Pain during sexual intercourse

[endtext]
http://www.youtube.com/watch?v=9Wb2BlQltn0endofvid

Episiotomy: Indications and Procedure video

Open Appendectomy : Operative Procedure Video

[postlink]http://tube.medchrome.com/2012/07/open-appendectomy-operative-procedure.html[/postlink]

[starttext]Definition: Open surgery is the traditional type of surgery where a long incision is made for the surgeon to insert the instruments, visualizing the surgery through the incision. With an open approach, the incision for a typical appendectomy is approximately 4 inches long.

Indications: 

1. When patient prefers open procedure (cheaper) 
2. When surgeon prefers open procedure (lack of surgical expertise and necessary equipments for laproscopic procedure) 
3. Laproscopic procedure is contraindicated (severe pulmonary disorders, bleeding diathesis, portal hypertension, intolerance of (ie, hypotension due to) Trendelenburg positioning, poor visualization, and severe adhesive disease from previous abdominal surgeries)

Operative procedure:

1. Preoperative preparations: General anesthesia, Supine position, Prophylactic antibiotics, Draping and exposure

2. Skin incision:

• Classical 'gridiron' incision: Incision through McBurney's point perpendicular to the imaginary line joining umbilicus and anterior superior iliac spine
• Cosmetic Laz incision: Horizontally over McBurney's point

3. Abdominal wall incision:

• Subcutaneous fat
• Superficial fascia
• Fat
• External oblique aponeurosis
• Internal oblique
• Transversus abdominis
• Vascular layer
• Parietal peritoneum
• Visceral peritoneum

4. Finding and delivering appendix:
a. Identify the cecum to identify appendix
b. If cecum is not identifiable, track the appendix following convergence of taenia
c. Forefinger palpates for appendix

• If mobile: pushed out from within
• If adherent: dissected out
• If truly retrocecal: division of lateral peritoneum followed by dissection of appendix

5. Dividing the blood supply:

• Appendix is held with babcock forceps
• The vessels are clipped and ligated after pushing holes in meso-appendix on either side 

6. Removing the appendix:

• Tie appendix base
• Invert the stump with a purse-string suture
• Crush appendix with hemostat at the site of tie

7. Peritoneal toileting

8. Closure: using absorbable sutures

• Peritoneum: Continuous
• Internal oblique muscle: Loose interrupted
• External oblique aponeurosis: Continuous
• Skin: Subcuticular if not inflamed and left open for delayed primary suturing if infected

[endtext] http://www.youtube.com/watch?v=AYXGN_-CiTQendofvid

Open Appendectomy : Operative Procedure Video

Cesarean section (LSCS): Operative procedure

[postlink]http://tube.medchrome.com/2012/07/cesarean-section-lscs-operative.html[/postlink]

[starttext]Cesarean section is an operative procedure to deliver a viable fetus or more through and abdominal and uterine incisions.

Indications for Cesarean section:

Maternal factors:

1. Prior classical C-section
2. Active genital herpes infection
3. Cervical carcinoma
4. Maternal trauma/demise

Fetal and Maternal factors:

1. Cephalopelvic disproportion
2. Placenta previa
3. Placenta abruption
4. Failed operative vaginal delivery
5. Post-term pregnancy

Fetal factors:

1. Fetal malposition
2. Fetal distress
3. Cord compression
4. Erythroblastosis fetalis

Contrainidcations of Cesarean section:

1. Dead fetus: except in extreme degree of pelvic contraction, neglected shoulder or severe accidental hemorrhage
2. Disseminated Intravascular Coagulation (DIC)
3. Extensive scar or pyogenic infection in the abdominal wall

Operative Procedure:

1. Anaesthesia: Usually done in spinal anaesthesia , sometimes under GA like in the cases of Eclampsia or Severe PET. The patient is tilted 10 to 15 degrees to her left using a wedge or blanket. This is done to avoid vena caval compression by her uterus (supine hypotensive syndrome)

2. Cleansing and Draping:The skin should be cleansed preferably with Povidone-iodine 7.5% in order to prevent surgicial site infection.
Surgical site should be draped with nonadhesive drapes if possible. These have been shown to be associated with a lower rate of wound infection than adhesive drapes.

3. Abdominal incision: A transverse skin incision is associated with reduced postoperative pain and is more esthetically acceptable to patients compared with a vertical incision (classic). The Pfannenstiel incision is slightly curved and made 2 to 3 cm above the symphysis pubis. The incision should allow for at least 15 cm of exposure. The skin and subcutaneous fat is incised with electrocautery.

4. Uterine incision: The anterior rectus sheath is incised transversely. The rectus muscles are separated in the midline. The parietal peritoneum is opened. The loose peritoneum over the lower uterine segment is held and incised transversely, for about 10 cm in a semilunar fashion with its edges directed upwards. The bladder is dissected downward and is retained behind a Doyen's retractor placed over the symphysis. Membranes are ruptured by toothed or Kocher’s forceps.

5. Delivery of the infant: The head is delivered by introducing the right hand gently below it and lifting it up helped by fundal pressure done by the assistant, using one blade of the forceps or, using Wrigley’s forceps. If the head is deep in the pelvis it can be pushed up vaginally by an assistant. The Doyen’s retractor is removed after the hand or forceps blade is applied and before head extraction. Suction for the foetus is carried out before delivery of the head. In breech or transverse lie the foetus is extracted as breech. Once the umbilical cord is clamped and cut, it is time to deliver the placenta via spontaneous extraction. Gentle traction is placed on the cord and oxytocin is used to enhance uterine contractions. The placenta is checked to make sure it is complete and the uterus is explored with one hand to remove any remaining membranes or placental tissue. The uterus is than massaged to promote contraction. Oxytocin is given to promote uterine contraction and involution.

6. Closing the uterus:  Closure of the uterine incision is done in 3 layers. The first is a continuous locking suture taking most of the myometrium but not passing through the decidua to guard against endometriosis and weakness of the scar. The second is a continuous or interrupted one inverting the first layer. The third is a continuous or interrupted layer to close the visceral peritoneum of the uterus. Similarly, the rectus muscles are not surgically reapproximated. The fascial tissue is carefully closed to provide good wound strength and the skin is closed with a subcuticular suture.

7. Closing the incision: Abdomen is then closed in layers

Complications

A. During operation:

• Uterine atony
• Bladder injury

B. After operation:

• Infections: Endometriosis, Wound infection or dehiscence
• Abdominal wall hematoma
• Urinary tract infection

[endtext]
http://www.youtube.com/watch?v=gJeRWGxOTcAendofvid

Cesarean section (LSCS): Operative procedure

Electron transport chain and Oxidative phosphorylation Animation

[postlink]http://tube.medchrome.com/2012/04/electron-transport-chain-and-oxidative.html[/postlink]

[starttext]

1. Mitochondrial Respiratory or Electron transfer chain is located in inner mitochondrial membrane
2. Substrate are oxidized and e- released passes from Complex of low redox potential to higher redox potential, eventually being added to O2 at complex IV to form H₂0 
3. At complex I, III and IV, energy generated is used to proton pump (H+) inner mitochondrial membrane (Coupling sites/ Sites of ATP generation coupled with oxidative phosphorylation) 
4. Oxidative phosphorylation: The proton gradient so created is released by passing protons back across inner membrane throught the ATP synthase (Complex V) resulting in ATP generation from ADP (3 for NADH – Complex I, III and IV and 2 for FADH2 – Complex III and IV i.e. Complex I bypassed) 

• Complex I (NADH dehydrogenase)

• Complex II (Succinate dehydrogenase) 

• Complex III (Cytochrome C reductase) 

• Complex IV (Cytochrome C Oxidase)

• Complex V (ATP synthase) 

         NADH → Complex I → Q → Complex III → cytochrome c → Complex IV  → O2

                            ↑

                        Complex II 

                            ↑

                           FADH

Inhibitors of Respiratory chain:

1. Complex I : Barbiturate, Piericidin
2. Complex II: Carboxin, M
3. Complex III: BAL, Antimycin
4. Complex IV: Cyanide, Carbon monoxide

Cyanide poisoning:

1. Binds irreversibly to cytochrome a/a3 (complex IV) preventing electron transfer to oxygen, producing many of the same changes seen in tissue hypoxia. 
2. Sources of cyanide include: Burning polyurethane (foam stuffing in furniture and mattresses) and Byproduct of nitroprusside (released slowly; thiosulfate can be used to destroy the cyanide)
3. Nitrites may be used as an antidote for cyanide poisoning if given rapidly. They convert hemoglobin to methemoglobin, which binds cyanide in the blood before reaching the tissues. Oxygen is also given if possible.

Inhibitors of Oxidative phosphorylation:

1. Uncouplers (Shunts H+ preventing pumping by ATP synthase) : 2,4 Dinitrophenol (2,4 DNP), thyroxine, thermogenin in brown fat
2. Inhibitors of ATP translocase: Atractyloside
3. Inhibitor of ATP synthase: Oligomycin

Respiratory control:

When Oxygen is limited:

↓O2 → ↓oxidative phosphorylation → ↑[NADH] & [FADH2] → (-)TCA cycle

When Oxygen is adequate:

↑[ADP] → (+)isocitrate dehydrogenase → ↑TCA → ↑[NADH] & [FADH2] →   ↑electron transport → ↑[ATP]

[endtext]
http://www.youtube.com/watch?v=xbJ0nbzt5Kwendofvid 

Electron transport chain and Oxidative phosphorylation Animation

How to Remember Dukes Criteria for Infective Endocarditis : Mnemonic

[postlink]http://tube.medchrome.com/2012/03/how-to-remember-dukes-criteria-for.html[/postlink]

[starttext]
Mnemonic: Bacterial Endocarditis FIVE PM

Major Criteria

B : Blood culture +ve

1. Typical micro-organisms in 2 seperate cultures or
2. Persistently +ve blood cultures drawn 12 hours apart or
3. Single +ve blood culture for Coxiella burnetti

E : Endocardial involvement

1. +ve echocardiogram (vegetation, abscess or valve dehiscence) or
2. New valvular regurgitation

Minor criteria

1. Fever > 38 oC 
2. Immunologic phenomena (glomerulonephritis, Osler’s nodes, Roth’s spots, Rheumatoid factor)
3. Vascular phenomena (major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjuntival hemorrhage, Janeway lesions)
4. Echocardiography findings (suggestive but not definitive)
5. Predisposition (heart condition or IV drug user) 
6. Microbiologic evidence (Positive blood culture but not meeting major criteria)

Definitive Diagnosis requires 2 Major  or 3 Minor + 1 Major or  5 Minor [endtext]

http://www.youtube.com/watch?v=m54F2em4lWwendofvid

How to Remember Dukes Criteria for Infective Endocarditis : Mnemonic