Paracentesis - Procedure Technique

Paracentesis is a procedure to take out fluid that has collected in the abdomen the peritoneal fluid. This fluid buildup is called ascites Ascites may be caused by infection, inflammation, an injury, or other conditions, such as cirrhosis or cancer. The fluid is taken out using a long, thin needle put through the belly. The fluid is sent to a lab and studied to find the cause of the fluid buildup.
Removal and analysis of peritoneal fluid is important in evaluating patients with new onset ascites or ascites of unknown etiology. It is also indicated in patients with known ascites who have a decompensation in their clinical status.

Relative contraindications include

• bleeding diathesis, 
• prior abdominal surgery,
•  distended bowel, or 
• known loculated ascites.

Preparation Before the Procedure; 

• Prior to performing a paracentesis, any severe bleeding diathesis should be corrected.
• Bowel distention should also be relieved by placement of a NG tube, and the bladder should also be emptied before beginning the procedure. 
• If a large-volume paracentesis is being performed, large vacuum bottles with the appropriate connecting tubing should be obtained.

Lumbar Puncture

A lumbar puncture (also called a spinal tap) is a procedure to collect and look at the fluid (cerebrospinal fluid, or CSF) surrounding the brain and spinal cord. During a lumbar puncture, a needle is carefully inserted into the spinal canal low in the back (lumbar area). Samples of CSF are collected.
Evaluation of CSF is essential for the diagnosis of suspected meningeal infection, subarachnoid hemorrhage, leptomeningeal neoplastic disease, and noninfectious meningitis.

Relative contraindications to LP include 

• local skin infection in the lumbar area, 
• suspected spinal cord mass lesion, and 
• a suspected intracranial mass lesion. 

Preparation: 

• Any bleeding diathesis should also be corrected prior to performing LP to prevent the possible occurrence of an epidural hematoma. 
• A functional platelet count >50,000/μL and an international normalized ratio (INR) <1.5 are advisable to perform LP safely.
• In patients with an altered level of consciousness, focal neurologic deficits, or evidence of papilledema, an imaging study should generally be obtained prior to performing LP.

Technique: 

• Proper positioning of the patient is essential; either the lateral decubitus or the sitting position can be used. 
• Most routine LPs should be performed using the lateral decubitus position .The sitting position may be preferable in obese patients. 
• With either position, the patient should be instructed to flex the spine as much as possible. 
• In the lateral decubitus position, the patient assumes a fetal position with the knees flexed toward the abdomen; the shoulders and pelvis should be vertically aligned without forward or backward tilt. 
• In the sitting position, the patient should bend over a bedside table with the head resting on folded arms.

Thoracocentesis - Procedure Description.

Thoracocentesis or pleural tap, is an invasive procedure to remove fluid or air from the pleural space for diagnostic or therapeutic purposes.
Drainage of the pleural space can be performed at the bedside.

Indications for this procedure include

• diagnostic evaluation of pleural fluid, 
• removal of pleural fluid for symptomatic relief, and 
• instillation of sclerosing agents in patients with recurrent, usually malignant pleural effusions.

Preparation: 

• Familiarity with the components of a thoracentesis tray is a prerequisite to performing a thoracentesis successfully. 
• Recent posterior-anterior (PA) and lateral chest radiographs with bilateral decubitus views should be obtained to document the free flowing nature of the pleural effusion. 
• Loculated pleural effusions should be localized by ultrasound or CT prior to drainage. 
• Management should be individualized in patients with a coagulopathy of thrombocytopenia. Thoracentesis is more challenging in patients with mechanical ventilation and should be performed with ultrasound guidance if possible.

Precautions While Performing Medical Procedures

Universal precautions should be used whenever an invasive procedure exposes the operator to potentially infectious body fluids. Not all patients infected with transmissible pathogens can be reliably identified. Because pathogens transmitted by blood and body fluids pose a hazard to personnel caring for such patients, particularly during invasive procedures, precautions are required for routine care of all patients whether or not they have been placed on isolation precautions of any type.

The CDC calls these universal precautions.

1. Wash hands before and after all patient contact.

2. Wash hands before and after all invasive procedures

.3. Wear gloves in every instance in which contact with blood or body fluid is certain or likely. For example, wear gloves for all venipunctures, for all IV starts, for IV manipulation, and for wound care.

4. Wear gloves once and discard. Do not wear the same pair to perform tasks on two different patients or to perform two different tasks at different sites on the same patient.

5. Wear gloves in every instance in which contact with any body fluid is likely, including urine, feces, wound secretions, and fluid encountered in respiratory tract care, thoracentesis, paracentesis.

6. Wear gown when splatter of blood or body fluids on clothing seems likely.

Chorionic Villus Sampling

It is one of the obstetric procedures and is summarized as follows:

Procedure:
-This is a diagnostic outpatient office procedure performed under ultrasound guidance without anesthesia.
-The catheter is placed directly into the placental tissue without entering the amniotic cavity.
-Chorionic villi, which are placental precursors, are aspirated from a pregnant uterus between 10 and 12 weeks’ gestation.
-The tissue is sent to the laboratory for karyotyping.
-The chromosomes of the villi are almost always identical to those of the embryo.

Nature of Tissue Obtained:
The procedure can be performed either transcervically or transabdominally. Since the fetus and chorionic villi are both derived from a common origin (the zygote), their karyotype is identical more than 99% of the time.

Important Neurological Investigations

There are a large number of neurological disorders and so a number of different investigations are available to help reach the proper diagnosis and then accordingly a proper management.

Here we can discuss a few important ones:

X- Ray Skull
It may show

• Fracture of skull valut or base.
• Enlargement or destruction of pituitary fossa due to tumor or raised intracranial pressure.
• Intracranial calcification due to tuberculoma.

X- Ray Spinal cord
It may show fractures, spondylosis ( degenerative bone disease ) or any destructive bone lesion due to infection or metastasis.

Computed Tomography ( CT Scan )It is an x-ray slice of 5-10 mm thickness in which different tissues have different densities.

Hypodense tissues ( looking blackish )

• Infarction, tumor, abscess(having white rim and black center), cerebral edema, encephalitis and resolving hematoma.
• CSF and air looks blacker.

Hyperdense tissues ( looking Whitish )

• Bone, blood(hemorrhage) and calcifications.

Advantages of CT scan

• CT scan easily demonstrates
• Cerebral tumors
• Intracerebral hemorrhage and Infarction
• Subdural and Extradural hematoma
• Subarachnoid hemorrhage
• Lateral shift of midline structures
• Cerebral atrophy
• Pituitary mass lesion

A Brief Discussion On Urinalysis

Urinalysis means examining or testing the urine and it is one of the most common and easy method used for medical diagnosis. It involves the physical, chemical, and microscopic examination of urine.

A part of a urinalysis can be performed by using urine test strips, known as Dipstick in which the test results can be read as color changes. Another method is examination of the urine sample under light microscopy.

Physical Or Macroscopic Examination Of urine
The first part of a urinalysis is direct visual observation:

1. Colour
Normal color of the urine ranges from colorless to deep yellow depending on the concentration of the urochorme pigment. Different colors may be observed in different conditions like red with blood in the urine or certain food colors e.d beetroot. orange with rifampicin, yellow in jaundice or dehydration and black with severe hemoglobinuria.

2. Volume
Normal volume is 800-2600 ml/day and it is referred to be oligouria if its < 300 ml/day and anuria if < 100 ml/day.

3. Appearance
A normal urine sample appears clear on visual inspection. Turbidity or cloudiness may be caused by excessive cellular material or protein in the urine or may develop from crystallization or precipitation of salts upon standing at room temperature or in the refrigerator. Clearing of the specimen after addition of a small amount of acid indicates that precipitation of salts is the probable cause of tubidity.

Introduction to Renal Biopsy

Renal biopsy is not a commonly performed procedure in medical practice but it is sometimes indicated when it has diagnostic value in certain kidney diseases. Most cases of acute renal failure are due to pre renal causes or acute tubular necrosis and recovery of renal function typically occurs over a course of few weeks. Renal biopsy should only be performed if knowing the histology will help in the management. Once chronic renal failure is established, the kidneys are small, may be hard to biopsy, and theresults are usually unhelpful.

Indications

• To determine the cause of unexplained renal failure.
• Persistent Heavy proteinuria >1gm/24hrs
• Investigating the cause of adult nephritic syndrome with persistent hematuria.
• Childhood nephritic or nephrotic syndrome that are unresponsive to treatment.
• Systemic disease with renal involvement like sarcoidosis, amyloidosis.
• Post transplant renal dysfunction.

Contraindication

• Underlying disorder of coagulation.
• Thrombocytopenia.
• Uncontrolled hypertension.
• Solitary kidney (except in transplanted kidneys).
• Small contracted kidneys i.e < 60% of expected bipolar length because it is technically difficult, histology is hard to interpret and prognosis cannot be altered.
• Uncooperative patient.

Investigations Required In Patients With Ascites

Ascites is defined as collection of excess free fluid in the peritoneal cavity and it could be due to a number of different medical conditions. A proper history and clinical examination may reveal the underlying cause but still certain general and specific investigation are to be carried out in order to confirm or find out the possible etiology.

General Investigations

1. Urine Dipstick: It is a simple and cheap procedure that will be strongly positive for protein in nephrotic syndrome. If so, a 24 hour urine collection for protein should be undertaken; more than 3.5gm is indicative of nephrotic syndrome.

2. Complete Blood Count: Raised white cell count may indicate an infective etiology but a differential white count is more specific.

3. Urea and Electrolytes: Elevated urea and creatinine may indicate a renal etiology; however , it may also be a component of hepatorenal syndrome, which is renal impairment secondary to liver failure.

4. LFT’s : May be deranged in the presence of liver disease. The serum albumin will be able to indicate hypoalbuminaemia but the underlying cause must still be sought.

5. Chest X-ray: Findings suggestive of cardiac failure are cardiomegaly, upper venous diversion of blood, the presence of Kerley B lines, pulmonary edema and pleural effusion. Occasionally the presence of carcinoma may be suggested by a mass in the lung.

6. Ultrasound Abdomen: In addition to confirming the presence of ascites ultrasound will detect any intra abdominal masses that are not palpable on clinical examination. It may also indicate the presence of fatty deposits in the liver in the presence of cirrhosis. Dilated collateral veins may be visualized in conditions that cause obstruction of the venous outflow of the liver, including cirrhosis and Budd-Chiari syndrome.

7. Abdominal Paracentesis: Aspiration of the ascitic fluid is very useful to help determine the underlying cause. A sample should be sent to microbiology clinical chemistry and pathology.

Ascitic fluid Examinations

Arterial Blood Gas Sampling - Brief Description Of The Procedure

Arterial Blood Gas Sampling is done to measure the oxygen and carbon dioxide tensions and acid–base status of arterial blood.

Indications: Arterial blood gas sampling was a research procedure until the mid-1960s but is now widely performed,either by direct arterial puncture or from indwelling arterial lines.
Indications include:
• respiratory failure (type I or II);
• renal failure;
• hepatic failure;
• cardiac failure;
• drug intoxication (aspirin and narcotics);
• endogenous acid overproduction (ketoacidosis or lactic acidosis);
• severe illness, cause unknown.

Contraindications: Care should be taken in the presence of bleeding disorders. Renal physicians will be appropriately unimpressed if an arterial blood gas sample is taken from an arteriovenous fistula.

What The Patients Should Know Before The Procedure: The procedure should be explained to the patient. The possibility of requiring more than one attempt should be mentioned.

A Brief Description Of The Practical Procedure:
1.Before investigation: The patient should be lying or sitting comfortably and an appropriate site is selected. The radial artery of the non-dominant arm is most commonly used, but the brachial or