Lecture 7: Fluid loss and management
- 1. Lecture-7 LOSS OF BODY FLUID AND ITS CONSEQUENCES Dr Shamshad Majamaah University
- 2. • Describe the various causes of loss of body fluids • Discuss the consequences of hemorrhage • Define vomiting and diarrhea • Discuss the management of fluid loss from the body Objectives Suggested reading : :Guyton and Hall “Textbook of Medical Physiology”13thed (pg. 294-296, 803-804) -:Current Medical Diagnosis and treatment 2021.
- 4. • Pleural fluid • Pericardial fluid • Peritoneal fluid • Synovial fluid • Cerebrospinal fluid • Intraocular • Urinary lumen • GIT lumen
- 5. Input and out of body fluid
- 6. 1: Renal Tubular disorder: Genetic Acute renal injury, salt losing nephropathy renal tubular acidosis (recovery phase) Chronic renal disease Diuresis: diuretics use, osmotic or postobstructvie. Pathological causes of Body fluid loss
- 7. 2: Non-renal • Hormonal : Adrenal insufficiency, Diabetes Insipidus & D mellitus • GIT losses Upper : Nasogastric suction , vomiting Lower: diarrhea, enteric or pancreatic fistula , Ileostomy or colostomy,tube drainage… • Dermal losses: Sweat ,burns… • Transcellular fluid loss: Pleural & Pericardial effusion, Ascites, Intestinal obstruction… • Hemorrhage: Internal or external • Rhabdomylosis
- 8. Mild Moderate Severe Water loss (ml) <50 ml/kg body wt 50-100 ml/kg body wt >100ml/kg body wt body weight ( %) <5% 5-10 % >10 % Skin & mucous Slightly dry Dry and pale Grey and mottled parched Eye balls sunken Slightly moderate Deeply Oliguria slightly moderately Anuria Peripheral circulation Heart rate Normal Normal Cool Increased Cool, weak and thread pulse ,shock with decreased BP Alertness mental condition Normal to slightly irritable Irritable Unconscious to comatose state Anterior fontanelle Normal depressed depressed
- 9. Most common cause of hypovolemia: Hemorrhage Decreases filling pressure of circulation Leads to Decrease cardiac output Ensues shock
- 10. Relationship of Bleeding Volume to Cardiac Output and Arterial Pressure: • About 10 % of the total blood volume can be removed with almost no effect … • But > 10 % loss diminishes the cardiac output first and later the arterial pressure, • >35-45 % blood loss FATAL
- 11. The decrease in Arterial Pressure after hemorrhage causes powerful sympathetic reflexes by the arterial baroreceptors and other vascular stretch receptors). resulting in three important effects: (1) The arterioles constrict in most parts of the systemic circulation, thus increasing the total peripheral resistance.
- 12. 2) The veins and venous reservoirs constrict, to maintain adequate venous return. 3) Heart activity increases leading Increase Cardiac Output Importance of the Sympathetic Nervous Reflexes Protect the cerebral and coronary circulation The reflexes extend the amount of blood loss that can occur without causing death to about twice that which is possible in their absence.
- 13. Shock stages : 1. Non-progressive stage (compensated stage):- The normal circulatory compensatory mechanisms eventually cause full recovery without help from outside therapy.
- 14. Mechanism 1. Baroreceptor reflexes, Powerful sympathetic stimulation of the circulation. 2. Central nervous system ischemic response, More powerful sympathetic stimulation throughout the body. But not activated significantly until the BP falls < 50 mm Hg. 3. Reverse stress-relaxation of the circulatory system, Causes the blood vessels to contract provides more adequately fills the circulation.
- 15. 4. Formation of angiotensin by the kidneys, Constricts the peripheral arteries Thus decrease output of water & salt by the kidneys. 5. Formation of vasopressin (antidiuretic hormone) Constricts the peripheral vessels Thus increases water retention by the kidneys.
- 16. 6. Compensatory mechanisms :Absorption of fluid From the intestinal tract, Into the blood capillaries from the interstitial spaces of the body, Conservation of water & salt by the kidneys, Increased thirst & increased appetite for salt makes the person drink water and eat salty foods if able.
- 17. Duration of action: Angiotensin, vasopressin & reverse stress-relaxation : Requires 10 minutes - 1 hour to respond completely, Readjustment of blood volume by absorption of fluid from the interstitial spaces and intestinal tract, oral ingestion and absorption of additional quantities of water and salt, Requires 1 – 48 hours.
- 18. 2. Progressive stage:- Without therapy, the shock becomes steadily worse until death. 3. Irreversible stage:- The shock has progressed to such an extent that all forms of known therapy are inadequate to save the person’s life, even though, for the moment, the person is still alive.
- 20. The forceful expulsion of gastric contents through oral route The sensory signals that initiate vomiting originate mainly from the pharynx, esophagus, stomach, and upper portions of the small intestines. Once the vomiting center sufficiently stimulated act of vomiting is instituted. Vomiting centers triggered by other modality with sensory signals originated from GIT: Ex: Drugs / motion & vestibular stimulation…. Vomiting
- 21. Various causes of vomiting
- 22. Vomiting reflex
- 23. Results from rapid movement of fecal matter through the large intestine. Clinical Causes: eg: o Enteritis: Causes ..? Site ..? Mechanism of action ..? (motility / toxin / secretion) The amount can be 10 to 12 liters per day, although the colon can usually reabsorb a maximum of only 6 to 8 liters per day. o Psychogenic Excessive stimulation of the parasympathetic nervous system, An examples : … ? o Allergic / immunomediated / others : Diarrhea:
- 24. I: Investigation: II: Treatment: 1- General Measures Basic life support with an assessment of the patient’s airway, breathing, and circulation. Vital signs monitoring Oxygen therapy Establish I.V line (central / peripheral). What's your DDx ? React accordingly 2- Volume replacement Fluids / blood / electrolyte replacement 3- Medications a. Vasoactive therapy b. Corticosteroids c. Antibiotic ?? 4- others: Management
Editor's Notes
- #24: Bacterial, viral, fungal, immune, causes Site: small or large intestine Psychogenic anxiety stress, anxiety bowel syndrome,