2. Aim of this 2 parts class: 1. To give you guys attendance. 2. Theoretical, conceptual & practical know how 3. To able you to understand the burden, mechanism, morphological, micro features 4. To differentiate between freshwater and saltwater drowning 5. To differentiate between AM and PM drowning 6. To estimate the duration & Site of incidence.
5. Specific Gravity and Density Specific gravity is defined as the ratio of the density of a substance to the density of water. Water has a specific gravity of 1.0 Any object with a specific gravity less than1.0 will float in water and anything greater than 1.0 will sink The human body has a density slightly less than that of water and averages a specific gravity of 0.974. Therefore, we float. Lean body mass has a typical density near 1.1 Fat mass has a density of about 0.9.
7. SEQUENCE OF EVENTS IN DROWNING 1. SENSE OF PANIC Expressed by: Violent struggle Automatic swimming movements Usually followed by: 2. PERIOD OF VOLUNTARY APNOEA Duration: 1-2 minutes. Hypoxemia, hypercapnia, R & M acidosis.
8. 3. ATTEMPT AT TAKING A BREATH WATER: May be freely inhaled Or, may cause glottic spasm due to impingement. In 10-15 % victims: glottic spasm severe asphyxia water may not enter the lungs unless subcouncious. Dry drowning In 85-90 % victims: water is swallowed inducing vomiting, gasping & aspiration of water into lungs. When expiratory effort is made: fine froth, sometimes blood stained (due to overdistension of liquid coloumn) Wet drowning
9. 4. Cessation of constant struggling 5. Stage of convulsive spasms, twitching, dilation of pupils 6. Clinical death
12. More liquid in the circulation Hemodilution, decrease in Na+, Cl & Ca conc. Liquid/ water goes inside RBCs Hemolysis Release of K+ Increase in K+ conc.
13. Marked Ventilation perfusion mismatch Shift Acute hypervolemia Experimental Vs Reality Increase in K+ irritates myocardium Arrythmias (VF) occurs
14. Effect on CVS Increase in circulatory volume but till plateau. Decrease in blood density Dec in Na, Cl
15. Salt water Drowning Pulling out of water Hemoconc. Inc. in Na, Cl and Mg No hemolysis, No VF Death within 5-12 minutes (later than freshwater)
16. Hypertonic liquid Pulmonary edema within minutes Shift Hypovolemia Draws water out through mb Into pulmonary alveoli Damage to basement mb + Dilution & washing out of Surfactant compliance decreased
18. Effect on CVS CVS effects are secondary to: 1. Changes in arterial oxygen tension 2. Changes in acid base balance. Acute hypoxemia Catecholamine release Transient tachycardia and hypertension. Followed by bradycardia and hypotension as hypoxemia intensifies. Hypoxemia may directly reduce myocardial contractility Hypoxia + Acidosis: increase the risk for arrythmias( VT, VF, Asystole) Note: VF as an immediate cause of death is uncommon in both forms of human drowning.
19. Effects on Brain Hypoxia ischemic damage to brain Window period of 4-6 minutes before irreversible neuronal damage.
20. Effects on other organs Acute renal and hepatic insufficiency GI injuries DIC
22. Types of drowning 1. Wet drowning= primary drowning 2. Dry drowning= 10-15%, laryngospasm, thick mucous foam plug, panoramic views of past life, pleasant dreams without distress. 3. Secondary drowning= post immersion syndrome= near drowning; Secondary drowning is death due to chemical or biological changes in the lungs after a near drowning incident; resuscitated and survives for 24 hours, +/- conscious, hypoxemia brain damage, electrolyte disturbances, pulmonary edema, hemoglobinuria, chemical pneumonitis 4. Immersion syndrome= hydrocution= submersion inhibition; cold water n. endings +/ strike epigastrium+/ entering ear drums, nasal passages. Horizontal entry (dive) pressure on abdomen All these Vagal inhibition Cardiac arrest death
23. RESPIRATORY SYSTEM In humans: As little as 1 to 3 ml/kg produces profound alteration in pulmonary gas exchange and decreases pulmonary compliance by 10 to 40%
24. Causes of death 1. Asphyxia 2. VF: disturbed Na/ K ratio (freshwater) 3. Laryngeal spasm 4. Vagal inhibition: cold water, emotions?, unexpected immersion. 5. Exhaustion 6. Injuries: # skull, cervical vertebrae.
25. MACRO-MORPHOLOGICAL CHANGES 1. FOAM/ FROTH: 1. Mushroom like froth from mouth, nostrils. 2. Foam inside mouth, in upper airways. Drowning liquid+ edema liquid+ fine air bubbles (resistant to collapse) Blood stained: mechanism? 3. External foam: most valuable finding D/D: 1. Cardiogenic PE 2. Epilepsy 3. Drug intoxication 4. Electrical shock
27. Clothing: wet Skin: wet, moist, pale ? Mud, silt, algae on body PM lividity: light pink in color Face: +/- cyanotic Conjunctivae: congested Pupils: dilated
28. Tongue: may be protruded or swollen Cutis Anserina: goose flesh? Reaction Phenomenon? Weed, grass, gravel in hand: due to cadaveric spasm. Soddening of skin of hands, feet/ shoes. Wrinkling Bleaching of epidermis in 4-8 hrs Washerwoman’s hands and feet 24-48 hrs.
30. 2. LUNGS: Emphysema Aquosum Imprints of ribs on pleural surface lung SR: Pale, mottled, red and grey areas Cut Section: Oozing of foamy liquid Subpleuralhges (Paltauf’s spots): 5-60% of drownings Lung weight: if taken alone, has little diagnostic value. Dry lungs: with no signs of aqueous emphysema (10-15%)
34. 3. PLEURA: PE: a relatively common finding Due to diffusion of liquid into thoracic cavity. 4. TEMPORAL BONE: Gross hges in the petrous and mastoid region of temporal bone Reasons: 1. Barotrauma 2. Penetration 3. Increased capillary & venous pressure
35.
36. 5. SINUSES: Aqueous liquid inside sinuses. Sign of permanence, can occur PM too. 6. SPLEEN: controversial Cut off value 0.2% body weight. Decrease in weight due to (proposed): symp. Stimulation V/c Contraction of the spleen capsule and trabeculae
37. 7. MUSCLES: Hges are seen, mostly in Resp & Aux resp ms > neck & back ms > ms of shoulder girdle > upper arm ms. Causes: Convulsions, hypercontraction, overexertion. 8. GI: Laceration of GI mucosa: vague
39. Alterations in blood Gettler Test: Normally, Cl content R=L, 600 mg/100 ml F.W.D= blood gets diluted by as much as 72 % in 3 minutes blood in the left side: Cl is 50 % lower than usual. S.W.D= Clconc increases (due to hemoconc) 25% difference= significant Value of the test= doubtful
40. Diatoms Microscopic, unicellular algae Siliceous skeleton = frustule Resist heat and acid. Active circulation brings diatoms into intestine, liver, brain, bone marrow. Technique: HNo3 or enzymatic digestion Centrifuge deposit PC or DGI Microscopy
44. Pressure is applied using the heel of one hand with the other hand on top, to depress the sternum 1 in. to 11/4 in. with each stroke in adults, followed by release of pressure, at the rate of about 60 per minute. The application of artfficial respiration and cardiac massage should be continued for at least 15 minutes If spontaneous respiration and restoration of the circulation do not occur within 15 minutes, further efforts are probably fruitless. If there is discernible evidence of active circulation, artificial respiration should be continued until spontaneous respiration is restored. On the other hand, marked body cooling or evidence of early rigor mortis indicates the futility of continued efforts in this direction. The presence of fixed dilated pupils persisting for 15 minutes is suggestive of clinical death.
45. In fresh-water drowning, this consists of 1000 c.c. of 3% saline, which is repeated in three to six hours if the serum sodium level is below 110 mEq./l. The deficit in serum calcium may need to be corrected by an infusion of calcium gluconate. Transfusion with whole blood, alternating with bleeding, may be needed later.
46. In salt-water drowning, intravenous therapy is carried out with 5% dextrose-never saline, whole blood or plasma. Venesection may be needed later.
47. anesthetic machine using intermittent pressure and pure oxygen. If the cardiac status is unsatisfactory, injections of epinephrine have been employed by some workers. If ventricular fibrillation has occurred, the use of external stimuli such as a quick blow over the heart, the application of electrodes with one or more shocks using 480 volts for .25 second,
48. In victims of fresh-water drowning the urinary output must be carefully observed; the hemolysis of red cells may cause renal tubular nephrosis.
49. under circumstances which induce emotions such as fear or surprise, the swimmer may be in such a state that an ordinarily innocuous stimulus will cause vagal inhibition and immediate cardiac arrest.
