ECC Pt. 3

Arterial Blood Pressure Monitoring

  • Methodologies for Measuring Blood Pressure

    • Indirect (Noninvasive) Methods

      • Doppler: Often considered seemingly more accurate and possesses more clinical uses.

      • Oscillometric Devices: Common examples include the Dynamap and Cardell units.

    • Direct (Invasive) Methods

      • Considered the gold standard of monitoring.

      • Requires the catheterization of an artery.

      • Utilizes specialized monitoring equipment including an arterial catheter, a transducer, and a monitor.

  • Procedures for Indirect Blood Pressure Measurement

    • Used primarily to measure systolic pressures.

    • Cuff Application:

      • An occlusion cuff is applied over an appendage.

      • The cuff width should be exactly 40%40\% of the circumference of the leg.

      • The cuff must be placed snugly around the leg and taped securely in place.

    • Potential Errors in Measurement:

      • If the cuff is applied too tightly, the pressure readings will be erroneously low.

      • If the cuff is too loose, the pressure measurements will be erroneously high.

      • Maintaining consistency regarding cuff size and patient position is vital for accurate data.

  • Mechanics of Direct Blood Pressure Monitoring

    • Technique: This is an invasive procedure requiring the placement of an arterial catheter.

    • Equipment: Requires a transducer and a mechanical transmitter.

    • Capabilities: It provides more accurate and continuous recordings of systolic, diastolic, and mean pressures through a series of waveforms.

  • Arterial Blood Gas (ABG) Analysis

    • This is a direct measurement of the oxygenation of arterial blood.

    • Function: It determines the partial pressure of oxygen available within the bloodstream.

    • Indicator: It serves as a direct indicator of how well the patient can oxygenate blood within the lungs.

    • Sampling: An invasive sample is typically taken from the femoral artery.

    • Precautions: Extreme care must be taken not to incorporate air bubbles into the sample.

    • Analysis: Immediate reading by a blood gas analyzer is imperative for accuracy.

  • Ideal Clinical Blood Pressure Values

    • Mean Blood Pressure: The normal range is between 75−90 mm Hg75-90\,mm\,Hg.

    • Hypertension: Indicated by systolic blood pressures greater than 175 mm Hg175\,mm\,Hg.

    • Pulse Palpation: Pulses should be palpable if the mean arterial blood pressure is greater than 60 mm Hg60\,mm\,Hg.

    • Vital Organ Perfusion: Maintaining adequate perfusion of vital organs requires systolic values greater than 90 mm Hg90\,mm\,Hg and diastolic values greater than 60 mm Hg60\,mm\,Hg.

Central Venous Pressure (CVP)

  • Core Concepts of CVP

    • CVP measures the blood pressure within the central veins.

    • Normal Range (Dog): The expected value is 0−5 cm H2O0-5\,cm\,H_2O.

    • Placement: Requires a long central venous catheter, typically placed in the jugular vein and advanced into the anterior vena cava.

  • Clinical Utility of CVP

    • Serves as a crude method to monitor a patient’s cardiac output.

    • Used as a marker in fluid therapy to assess how a patient is responding to treatment.

    • Acts as a useful marker for determining the overall perfusion status of the patient.

Coagulation and Renal System Monitoring

  • Coagulation Status Assessment

    • Monitoring is helpful for assessing unexplained bleeding and detecting Disseminated Intravascular Coagulation (DIC).

    • Blood Smear Evaluation: Used to detect changes in red blood cell morphology and provides an estimation of platelet numbers.

    • Buccal Mucosal Bleeding Time (BMBT): Evaluates platelet function and serves as an in-house screening test for von Willebrand’s disease.

  • Renal System Monitoring Protocols

    • Standard Procedures: Always perform urine-specific gravity before the administration of IV fluids whenever possible.

    • Laboratory Markers: Key markers include Blood Urea Nitrogen (BUN), creatinine, and phosphorous.

    • Urine Output Monitoring:

      • Output should be estimated and recorded in the medical record for all animals.

      • Critical cases require close monitoring via indwelling urinary catheters or cages designed with grates for drainage and collection.

      • Minimum Production: The threshold for minimum urine production is 1−2 ml/kg/hr1-2\,ml/kg/hr.

Care of the Recumbent Patient

  • Maintenance and Comfort Measures

    • Respiratory Care: Airway management including endotracheal or tracheostomy tube care.

    • Support: Providing appropriate bedding and ensuring patient comfort.

    • Medical Support: Administration of anesthesia or analgesia as needed.

    • Catheter Maintenance: Routine care for intravenous and urinary catheters.

    • Fluid Management: Strict monitoring of fluid balance, specifically "Ins and Outs."

  • Ongoing Physiological Care

    • Nutrition: Ensuring adequate nutritional intake.

    • Ocular Care: Performing a Fluorescein stain daily to check for corneal issues.

    • Oral Care: Regular cleaning and maintenance of the oral cavity.

    • Physical Therapy: Performing range of motion exercises to prevent stiffness and muscle atrophy.

Common Toxicities and Medical Emergencies

  • Respiratory Distress and Trauma

    • Respiratory Distress Management: Minimize patient stress, provide oxygen supplementation, and utilize sedation.

    • Trauma Management: Begin with a triage examination, provide immediate pain control, perform a secondary exam, and reassess the patient continuously.

  • Abdominal and Toxin Emergencies

    • Acute Abdomen: Recognized by sudden-onset abdominal pain; necessitates obtaining a complete patient history.

    • Gastric Dilatation Volvulus (GDV): Characterized by acute signs; requires initial stabilization, radiography, and surgical intervention through abdominal exploratory and gastropexy.

    • Toxin Exposure: Requires thorough questioning of the owner and decontamination efforts, such as the induction of emesis or gastric lavage.

  • Urinary Obstruction Management

    • Clinical Presentation: Patients may strain to urinate, appear stuporous, or present in hypovolemic shock.

    • Etiology: Causes include urinary stones, tumors, trauma, or inflammation.

    • Pathophysiology: These obstructions can be fatal. Metabolic abnormalities develop quickly, and secondary kidney damage may occur. In severe cases, the urinary system may rupture, leaking urine into the abdomen.

    • Diagnosis: Based on history (straining, painful urination, hematuria, or lack of urination), physical exams, lab tests, and imaging.

    • Laboratory Findings: Common abnormalities include Hyperkalemia, elevated kidney parameters, and metabolic acidosis.

    • Treatment Protocols:

      • Address and correct electrolyte disorders immediately, with a focus on Hyperkalemia.

      • Relieve the obstruction through urinary catheterization.

      • An indwelling urinary catheter is typically maintained for several days.

      • IV fluids are used to diurese the kidneys, correct electrolyte imbalances, and maintain hydration.