Vital Signs and Oxygenation

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Author:
kathleenagrace
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53564
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Vital Signs and Oxygenation
Updated:
2010-12-05 19:41:20
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nursing
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Test 2
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  1. Core Temperature
    • 36*C - 37.5*C
    • 97*F - 99.5*F
  2. Thermogulatory Center of the Brain?
    Hypothalamus
  3. Vital Signs:
    Temperature
    • Range: (oral) 37*C, 98.6*C
    • heat of body
    • indicates production (metab) and loss (skin)
    • depends on metabolism
    • lowest in early AM, highest in late afternoon
  4. Normal Temperatures for Healthy Adults
    • Oral: 37 C, 98.6 F
    • Rectal: 37.5 C, 99.5 F
    • Axillary: 36.5 C, 97.6 F
    • Tympanic: 37.5 C, 99.5 F
    • Temporal: 34.4 C, 94 F
  5. Vital Signs:
    Pulse
    • Range: 60-100 bpm (80 on avg)
    • [now: 50-90 bpm, 70 avg]
    • throbbing sensation palpated over peripheral artery, auscultated by apical HR, regulated by SA node
  6. Vital Signs:
    Respiration
    • Range: 12-20 breaths per minute
    • pulmonary ventilation, external and internal respiration
  7. Vital Signs:
    Blood Pressure
    • Range: ≤120/80 mm Hg
    • Blood flows through the vessels of the circulatory system from areas of higher pressure to lower pressure. Resistance to blood flow is also involved.
  8. Overview of Circulatory System
    • Two functions:
    • 1) deliver oxygen, nutrients, hormones, electrolytes to calls
    • (2)remove carbon dioxide from cells

    • Two Divisions of Circulation:
    • (1) Pulmonary: delivers blood to lungs
    • (2) Systemic: delivers blood to tissues (aka. Peripheral or greater circulation)
  9. Components of the Circulatory System
    (Heart and Blood Vessels)
    • Artery: transports high pressure blood to tissues
    • Arteriole: controls valves that regulate local blood flow
    • Capillaries: sites of exchange
    • Venules: collect blood form capillaries
    • Vein: transports blood back to heart; major reservoir of blood; 6-10 times more distensible (elastic) than arteries
  10. What makes blood flow?
    • “force that drives flow is greater than resistance to flow”
    • Blood flows from the high pressure area across pressure gradient into low pressure area
    • Resistance depends on vessel length, diameter, and blood viscosity
  11. How does blood get back to the heart?
    • Negative pressure (0 to -5 mmHg) in right atrium (due to chest expansion during inspiration) “sucks” blood back into heart
    • Constriction of smooth muscle in veins drive blood back to heart
    • Auxiliary “venous pump: of one-way venous valves and skeletal muscle constriction
  12. Determinants of Cardiac Output (CO):
    Equation, HR, SV, Preload, Afterload, Contractility
    CO = HR X SV (avg. is 4.9 L/min)

    • Heart rate (HR): (avg. 70 bpm Autonomic Nervous System (ANS)
    • --HR increases by sympathetic (SNS) stimulation of beta-adrenergic receptors in SA node
    • --HR decreases by parasympathetic (PNS) stimulating muscarinic receptors in SA node via the vagus nerve

    • Stroke volume (SV): (avg 70 mL)Myocardial contractility, cardiac afterload, cardiac preload; determined by factors affecting venous return
    • Preload: amount of tension (stretch) applied to muscle prior to contraction (depend on force of venous return); also called end diastolic pressure
    • Afterload: load against which a muscle exerts force (arterial pressure heart must overcome); if pressure increases, stroke volume decreases, if pressure decreases, stroke volume increases
    • Contractility: force with which ventricles contract, depends on stroke of ventricle dilation, which depends on venous return
  13. Starling’s Law:
    • force of ventricular contraction is proportional to muscle fiber length (ventricular diameter)
    • [because actin and myosin are better aligned with increased diameter during filling]

    • Want to maintain contractility of heart.
    • Force of contraction normal increases in proportion to how much ventricle fills.
    • If heart muscle is healthy and intact, it will stretch and contract back; repeat readily.
    • If heart is “sick” or worn-out/damages, it will stretch and stay; not retractable….
    • Eventually will break/fail.
    • Becomes extremely ineffective pump.
  14. Stroke volume is determined by factors that regulate venous return:
    Systemic filling pressure (force that returns blood to the heart) [normal is 7 mm Hg, can increase to 17 mm Hg during vasoconstriction]

    • Auxiliary muscle pumps
    • Resistance to flow between peripheral vessels and right atrium
    • Right atrial pressure (increase impedes venous return)
  15. Regulation of Arterial Pressure
    • Physiologic regulation:
    • AP = PR X CO
    • (arterial pressure=peripheral resistance X cardiac output)

    depends on peripheral resistance due to dilation/constriction of vessels and venous return affecting cardiac output
  16. Regulation of Arterial Pressure:
    Control systems: ANS
    • Autonomic Nervous system
    • (sec/min)

    responds rapidly to changes in blood pressure (baroreceptors in aortic arch and carotid sinus sense arterial pressure and tell medulla vasoconstriction center to constrict or dilate vessels)

    steady-state control (sympathetic steady-state tone maintains a moderate level of vasoconstriction so arterial pressure is not compromised)
  17. Regulation of Arterial Pressure:
    Control systems: RAAS
    Renin-Angiotensin-Aldosterone System (hours/days)

    • Constriction of arterioles and veins (angiotensin II)
    • Retention of water by kidney (aldosterone)
  18. Regulation of Arterial Pressure:
    Control systems: RAAS
    (long-term control over days/weeks)

    decreased renal blood flow and decreased glomerular filtration rate (plus aldosterone) causes increase in water retention -->increase fluid volume-->increase venous pressure--> increase venous return-->increase cardiac output-->increase arterial pressure
  19. What is Orthostatic Hypertension?
    blood pools when you stand up because veins dilate under the pressure caused by gravity; reversed by baroreceptors by constricting veins and arterioles and increasing HR
  20. Assessing Blood Pressure
    • Korotkoff sounds: sounds listened for in blood pressure assessment
    • Systolic pressure: first sound, faint tapping that gradually increases
    • Diastolic pressure: change or cessation of the loud sounds

    Osculatory Gap: if there is a gap between change in sound and cessation of sound, record as a 3-way fraction, ex. 120/80/64

    Required equipment: stethoscope and sphygmomanometer(always reset to zero), noninvasive/electronic, Doppler ultrasound, direct electronic (needle into artery)
  21. Assessing Blood Pressure:
    Sources of error
    • False Low: hearing deficit, noise in environment, cuff too wide, ear tips wrong, cracked/kinked tubing, released valve too rapidly
    • False High: calibration not at zero, taken after exercise, cuff too narrow, released valve too slow, reinflating cuff during auscultation
  22. Regulation of Body Temperature
    • Thermoregulation: hypothalamus, receptors in body tell body if it's hot or cold
    • Heat production: metabolism, increased by exercise, own endogenous hormones, diet/food intake
    • Heat loss: skin, sweat, elimination
    • Mechanisms:
    • --Increase in temp: hormones, exercise, thyroid, shivering, piloerection (goose bumps)
    • --Decrease temp: sympathetic open/closes arteriovenous shunts, sweat, elimination, methods of [radiation, convection, evaporation, conduction]
    • Other influences: circadian rhythm, age and gender, environment, stress
  23. Temperature:
    Equipment/Techniques
    • Equipment: electronic/digital (oral, rectal, axillary), Tympanic (ear canal), Glass (oral, not mercury—alcohol or petroleum based now), Disposable (patch or tape changes color), Temporal (across forehead), Automated (several vital signs simultaneously)
    • Sites: (most common are sublingual, axillary, tympanic)
    • --Tympanic: no drainage or scars
    • --Oral: close entire mouth around it
    • --Rectal: no infants/small children, rectal surgery, diarrhea, neutropenia
    • --Axillary: wait if just washed
  24. What is the Maximum Temp before Brain Damage occurs?
    106*F
  25. Heart Rate:
    Physiology/Variations
    • Physiology: autonomic nervous system, cardiac SA node
    • Parasympathetic: decreases heart rate through vagus nerve
    • Sympathetic: increases heart rate and force
  26. Tachycardia
    increased heart rate (100-180 bpm)
  27. Bradycardia
    decreased heart rate (less than 60 bpm)
  28. Dysrhythmia
    irregular pattern of heart beats
  29. Pulse Deficit
    difference between apical and radial pulse rate, indicates all heartbeats are not reaching peripheral arteries or are too weak to palpate
  30. Heart Rate:
    Equipment/Techniques
    Equipment: palpation, stethoscope (diaphragm for high frequency/lung sounds, bell for low frequency/heart sounds), Doppler ultrasound stethoscope, cardiac monitor

    • Sites:
    • -- Peripheral (using three middle fingers): *radial*, carotid/brachial (cardiac arrest), femoral, popliteal, posterior tibial, dorsalis pedis
    • -- Apical: if peripheral is difficult, if giving meds that alter HR and rhythm, space between 5th and 6th ribs, about 8cm/3in to left of median line, just below nipple
    • -- Apical-Radial: when radial is irregular, take both simultaneously
  31. Respiration:
    Regulatory Cntr, Cellular, Pulmonary
    • Respiratory centers: are medulla and pons
    • Cellular Respiration: mitochondria (powerhouse) Krebbs Cycle exchange process
    • Pulmonary ventilation: exchange of gases in lungs via alveoli and capillary membrane; inspiration (air in), expiration (air out); voluntary control in cerebral cortex; rate and depth changes with body’s demands, especially in high CO2 levels

    Ventilation does not mean profusion; oxygen can be taken in with ventilation
  32. Respiration:
    Factors Affecting
    age gender, exercise, acid-base balance, brain lesions (hemorrhage/tumor), increased altitude, respiratory diseases, anemia, anxiety, medications, acute pain

    • Profusion: can get air in but can’t get it out into body. Something that stops oxygen from being distributed.
    • Ex. COPD, pneumonia (PNA)

    Pneumonia: O2 sat (oxygen saturation) decreases. Blockage in alveoli prevents oxygen to transfer into capillary cells.
  33. Respiration:
    Assessment
    observing/listening or using a pulse oximeter for effectiveness of respirations

    Rate(breaths/min), depth (deep/shallow), rhythm (regular/irregular)
  34. Developmental Considerations For Respiration
    • --Baby’s lungs: fluid filled to air filled
    • --Children 2nd hand smokers
    • --Can hear crackles in lungs in infants and children; totally normal
    • --Elders have shallower breaths, sounds are more distant during oscultation (barrel chest: ribcage changes shape; sounds are further away), diaphragm moves less efficient, tissues tend to thicken with age.
  35. Oxygenation:
    Nursing Diagnoses
    • Ineffective airway clearance: cough
    • Impaired gas exchange (alveoli): cough and deep breath, give fluids
    • Intolerant of activity: pace activity, sit down, give fluids
    • Altered nutrition, less than body requirements
    • Knowledge deficit
  36. Eupnea
    normal respiration (12-20 per minute)
  37. Tachypnea:
    increase rate (increased metabolic rate with fever, high CO2 and low O2)
  38. Bradypnea
    decreased rate (intracranial pressure, narcotics)
  39. Apnea
    periods of no breathing (death can occur if no breath in 4-6 minutes)
  40. Dyspnea
    difficulty or labored breathing
  41. Orthopnea
    dyspneic people breath better when in sitting or standing position
  42. Afterload
    • arterial pressure that the left ventricle must overcome to eject blood
    • determined by peripheral resistance
  43. Peripheral Resistance
    • determined by constriction and dilation of arteriolds
    • amount of resistive force blood must overcome to flow through
  44. Baroreceptor Reflex
    • Receptors on aortic arch and carotid sinus
    • relay info to vasoconstrictor centro of the medulla
    • vasoconstrictor center will send appropriate instructions to compensate
    • (constrict/dilate to incr. or decr. HR)
  45. Postural Hypotension
    • reduction in arterial pressure when moving from supin or seated position to standing
    • blood pools in veins, auxiliary venous pumps and baroreceptor reflex fix it
  46. Cardiac Output
    • CO = HR X SV
    • approx 5 L/min
  47. Preload
    • (end diastolic pressure/volume)
    • amount of tension (stretch) applied to muscle prior to contraction
    • determined by force of venous return
  48. Ventricular Contractility
    • force with which ventricle contract
    • determined by cardiac dilation, which is determined by venous return
  49. RAAS System
    • 1. constriction of arteriolds and veins (ango II)
    • 2. retention of water by kidney (aldo)
    • control of blood pressure
  50. Venous Capacitance
    • dilation of veins allows for higher capacity
    • increased by ANP/BNP
  51. Natiuretic Peptides
    • 1. reduce blood volume
    • 2. promote dilation of arteriols/veins
    • protect cardiovascular system during volume overload (excessive retntion of sodium and water)

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