MC

Clinical Prep and Oxygen Transport Notes

Clinical dress rehearsal and program logistics

  • Date and purpose: Around Oct 21, Nardi leads a combined class. He covers dress rehearsal logistics: what you need to wear and bring before clinical life starts.
  • Dress and appearance requirements:
    • Uniform scrubs, badge on, stethoscope, and a watch with a second hand are required on day one of clinical life.
    • Hair must be tied back; nails must be kept short and modest (manicured/nail art not allowed for the semester). Gel nails or long nails may need to be skipped for the duration.
    • Accessories should be minimal; avoid flashy jewelry or anything that could interfere with clinical work.
  • Supervisors and check-ins:
    • Gomez (Bethesda, day shift supervisor) and Nardi (Jupiter, night shift supervisor) will visit to ensure compliance.
    • On Tuesdays, Nardi and Goldman will check in and call you out if something isn’t right.
  • Clinical placement details:
    • Nardi works at Jupiter (night shift); Gomez at Bethesda (day shift). Gomez doesn’t work on Tuesdays due to a math class; both will visit on Tuesdays.
    • Palm Beach State (PBSC) has a long-standing reputation for professionalism; other schools in the area include Nova, Kaiser, Concord, and Nova is located in Palm Beach Gardens.
    • PBSC nursing students wear blue scrubs (dark blue).
    • You will see PBSC nursing students as well as students from Nova, Kaiser, and Concord; competition is a consideration and the hospitals value PBSC graduates.
  • Program reputation and expectations:
    • The program has been around for about 35 years; hospitals expect PBSC students to be well-prepared.
    • Early impressions can be overwhelming, but the goal is to avoid embarrassment when you arrive for clinicals.
  • Early months and dress rehearsal specifics:
    • The first month is about getting prepared; some programs start clinical right away (e.g., radiology) and will use the dress rehearsal as a foundation.
    • Hair, nails, and other appearances are emphasized; gel nails or similar may have to wait.
  • Lab jackets and identification:
    • A green lab jacket is available; you may wear it if you have one that’s properly identifiable as a student.
    • Some hospitals may provide an initial set of scrubs or have color-coded scrubs by department to avoid confusion that a scrubbed person is a doctor.
    • Badges must be visible to identify you as a student (e.g., RN, RT, nursing, doctor, administration).
  • Complio, orientation, and required forms:
    • You will complete a Complio (online clearance system) process with a set of forms and modules.
    • Hospitals require orientation and policy modules (e.g., emergency codes). Wellington uses its own process, others use Complio.
    • There is a Zoom-based mandatory orientation on the first Tuesday in October (9–11 AM); the instructor will excuse you from class to attend.
    • A batch of forms will be loaded next week; the instructor will print and upload necessary documents and guide you through them.
    • Emergency codes vary by hospital (e.g., Code Blue, Red, Yellow, Pink, Silver, Gray, Green); you must learn the codes for each hospital you visit.
    • Some hospitals (e.g., Baptist system at Boca Raton and Bethesda) require approval that can take two to three weeks; most others take about a week once forms are complete.
    • You must sign up for an education account and complete hospital-specific modules (policies, charting basics, etc.) before going to clinical.
  • Flu shot and immunizations:
    • Flu shot is mandatory for most hospitals; deadlines are typically Nov 1 or Nov 15 (flu season defined as roughly Nov 1–Mar 15 or Nov 15–Mar 15).
    • If possible, obtain the flu shot through a hospital or free clinic; reimbursement may occur after May; mising flu shots can block clinical access.
    • The speaker emphasizes the need for immunizations to protect patients and families; the “blue shot” (flu vaccine) is hard to avoid.
  • Medical form and health clearance:
    • If a medical form is missing, it can block clinical placement; there are some overrides possible, but medical clearance is essential.
    • If needed, the student should obtain a medical form via a physician’s visit or “doc in the box” options.
  • Scheduling and next steps for the week ahead:
    • Next week, the instructor will load all forms and provide additional forms to fill out; it’s a bit of a hassle but necessary for compliance.
    • Monclio (Complio) clearance must be completed ASAP to avoid delays.
    • The upcoming test schedule: Test 1 is a week from today with 50 questions; Friday is the actual test day (date given as Oct 3, with a note about potential date adjustments).
    • The instructor will provide a PowerPoint with illustrations for complex topics (e.g., pulmonary function) to supplement the chapter; the aim is to identify likely test topics rather than line-by-line memorization.
  • Study strategy and exam design:
    • Expect a mix of questions; some will require identifying a topic within a scenario rather than direct recall.
    • For pulmonary function tests (PFTs), the two main types of diseases are obstructive and restrictive; the key indicator for obstruction is a low FEV1/FVC ratio; obstruction can have elevated TLC, RV, and FRC if not accompanied by restriction.
    • The instructor will review the critical concepts for the upcoming test and provide a structured review on Monday before the big assessment.
  • Practical guidance and classroom reality checks:
    • The goal is to help you prepare for the clinical environment: observe patient care first, then software and charts; always verify patient status by looking at the patient, not just the monitor.
    • If something seems wrong in the lab or a device, address it (e.g., turn off a flow meter that’s left on, fix an environmental safety issue).
    • The learning process includes balancing theoretical knowledge with practical, real-world clinical observation; the emphasis is on critical thinking and integration of multiple data points
    • The instructor emphasizes keeping a patient-centered approach: they want you to focus on patient care over screen data. This will be reinforced as you move into the clinical setting.
  • Hospitals, units, and sites mentioned:
    • Jupiter (Nardi’s night shift site)
    • Bethesda (Gomez, day shift site)
    • Nova (Nova Southeastern University at Palm Beach Gardens)
    • Kaiser and Concord programs in the area
  • Other notes and reminders:
    • There may be “gel nails” or other cosmetics that conflict with infection-control policies; consider temporary modifications during the first semester.
    • Attendance at the Zoom orientation is mandatory for Complio clearance; contact the instructor if you need accommodations.
    • Ensure you have a badge ready for clinicals and that you are easily identifiable as a student before you enter patient areas.

Oxygen transport and physiology: fundamentals and clinical implications

  • High-level overview:
    • The heart pumps blood that carries oxygen (O2) to tissues; oxygen can be transported in two ways: dissolved in plasma and bound to hemoglobin in red blood cells (RBCs).
    • The primary oxygen carrier is hemoglobin (Hb); each Hb molecule can bind a limited amount of O2, and a small fraction is dissolved in the blood plasma.
  • Hemoglobin and oxygen binding basics:
    • Hemoglobin details:
    • Hb concentration in blood is normally about 12–16 g/dL.
    • Each hemoglobin molecule can carry about 1.34 mL of O2; i.e., the binding capacity per Hb is 1.34 mL O2 per Hb molecule.
    • Hb contains iron in the heme groups and globin protein chains; four heme groups per Hb molecule allow binding of up to four O2 molecules.
    • Oxygen transport components:
    • In the lungs, oxygen diffuses from alveoli into blood and binds to Hb in RBCs. CO2 diffuses in the opposite direction and is released from Hb.
    • About 97% of the transported O2 is bound to Hb; about 2–3% is dissolved in plasma (the dissolved portion contributes to PaO2 but a small fraction of total O2 content).
  • PaO2, SaO2, and alveolar gas exchange:
    • Normal Alveolar PO2 is around 100 mmHg; deoxygenated blood returns with a much lower PO2, creating a diffusion gradient that drives loading of O2 onto Hb in the lungs.
    • SaO2 (arterial oxygen saturation) and PaO2 (arterial partial pressure of O2) are related by the oxygen-hemoglobin dissociation curve. For example:
    • When SaO2 ≈ 90%, PaO2 ≈ 60 mmHg.
    • When SaO2 ≈ 100%, PaO2 is near about 100 mmHg under typical conditions.
    • The dissociation curve is S-shaped (sigmoidal): at higher SaO2 values the curve is relatively flat (small changes in PaO2 cause small changes in SaO2), while at lower SaO2 values the curve becomes steep (small changes in SaO2 correspond to large changes in PaO2).
  • Oxygen delivery and oxygen extraction:
    • Oxygen delivery to tissues depends on three main factors:
    • Oxygen content of arterial blood (CaO2) driven by Hb concentration and SaO2.
    • Cardiac output (CO).
    • The efficiency of unloading of O2 from Hb at the tissue (tissue oxygen extraction).
    • Normal cardiac output is about 5–8 L/min in adults; some patients may have CO 12–15 L/min when hyperdynamic.
    • Mixed venous oxygen content (CvO2) reflects oxygen extracted by tissues; the arterial-venous oxygen content difference is a key indicator of tissue oxygen extraction and utilization (CaO2 − CvO2).
    • Typical oxygen extraction results in a noticeable drop from arterial to venous blood as blood circulates through tissues.
  • Dead space and shunting:
    • Dead space: ventilation without perfusion (air reaches alveoli that are not perfused by blood).
    • Shunt: perfusion without ventilation (blood accesses alveoli that are not adequately aerated).
    • Both affect overall oxygenation efficiency and must be considered in clinical assessment.
  • Oxygen content and how to think about it in practice:
    • Major components of blood oxygen content:
    • Bound O2: about 97% of total O2 is bound to Hb.
    • Dissolved O2: about 2–3% is dissolved in plasma.
    • Practical takeaway: measurements like SpO2 primarily reflect Hb-saturation, not the total O2 content; arterial blood gases give PaO2, which relates to dissolved O2 and the loading status, while Hb-bound O2 depends on Hb concentration and saturation.
  • The oxygen-hemoglobin dissociation curve in clinical reasoning:
    • Curve characteristics:
    • Left shift (higher affinity): easier loading of O2 onto Hb in the lungs, less unloading at tissues.
    • Right shift (lower affinity): easier unloading of O2 at tissues, less loading in the lungs.
    • Factors shifting the curve:
    • Right shift factors include acidosis (lower pH), higher temperature, increased CO2, and higher levels of 2,3-BPG (not all mentioned in the lecture, but conceptually part of curve shifting).
    • Left shift factors include alkalosis (higher pH) and lower temperature.
    • Carbon monoxide (CO) interaction:
    • CO binds Hb with ~200x higher affinity than O2, occupying binding sites and impeding O2 binding and unloading, which can lead to misleading pulse oximetry readings (SpO2 may appear normal or high despite tissue hypoxia).
  • Carbon monoxide poisoning and clinical implications:
    • Mechanism: CO preferentially binds Hb, forming carboxyhemoglobin, which reduces O2-carrying capacity and impairs O2 delivery to tissues.
    • Pulse oximetry limitations in CO exposure: pulse oximeters cannot distinguish carboxyhemoglobin from oxyhemoglobin; SpO2 can appear falsely high (near 100%). Arterial blood gas analysis with co-oximetry or CO-oximetry is necessary for accurate assessment.
    • Management considerations in suspected CO poisoning:
    • If CO exposure is suspected (e.g., smoke inhalation), give high concentrations of O2 but be mindful that SpO2 readings can be misleading.
    • The highest practical O2 delivery is preferred; a non-rebreather mask is commonly used to maximize oxygen delivery.
    • In severe cases or persistent symptoms, hyperbaric oxygen therapy may be considered to accelerate CO clearance and improve tissue oxygenation.
  • Cyanosis and clinical signs of hypoxia:
    • Hypoxemia: low oxygen in the blood; detected via arterial blood gas or pulse oximetry (SpO2).
    • Hypoxia: low oxygen delivery to tissues; can occur even if SpO2 looks acceptable due to delivery issues or tissue extraction problems.
    • Cyanosis is a visible sign of tissue hypoxia, particularly in peripheral tissues like lips, fingertips, and ear lobes.
  • Practical clinical correlations and test-style reasoning:
    • Example scenario (from lecture): A patient with high eosinophils and elevated airway resistance (e.g., 14 cmH2O/L/s) and expiratory wheezes with SpO2 around 92% on room air suggests obstructive disease such as asthma or an allergic reaction; this illustrates integrating multiple data points (labs, physical findings, and PFT indicators) to infer the underlying problem.
    • Key message: tests will not be purely from slides; they will synthesize data from multiple sources (blood gases, SpO2, PFTs, clinical presentation) to test critical thinking.
  • Quick reference numbers and concepts to memorize:
    • Normal Hb concentration: approximately 12–16 g/dL.
    • Oxygen-carrying capacity per Hb: about 1.34 mL O2 per Hb molecule.
    • Proportion of O2 carried bound to Hb vs dissolved: bound ≈ 97%, dissolved ≈ 2–3% of total O2.
    • Normal arterial O2 saturation: roughly 95–100%; an SaO2 of ~90% generally corresponds to PaO2 ~60 mmHg.
    • Normal arterial PO2 in alveolar gas: ~100 mmHg; normal venous PO2 is lower after tissue extraction.
    • Normal cardiac output: ~5–8 L/min; high-output states can reach 12–15 L/min.
    • Normal airway resistance: roughly 0.5–2.5 cmH2O/L/s.
  • Important clinical takeaway connections:
    • Oxygen delivery to tissues depends on Hb content, Hb saturation, cardiac output, and tissue extraction; problems in any of these can lead to hypoxia even if some others look normal.
    • Pulse oximetry is a useful noninvasive tool but has limitations (e.g., CO poisoning, erroneous readings due to poor probe placement or external factors such as a blood pressure cuff inflating on the same arm).
    • In environmental/acute care scenarios (e.g., smoke inhalation), aggressive oxygen therapy is used, but CO poisoning requires special interpretation and management, including consideration of hyperbaric oxygen therapy for select cases.
  • Study and exam-oriented takeaways:
    • Be comfortable with the basic O2 transport framework: lungs → alveoli → capillary diffusion → Hb loading → systemic circulation → tissue unloading → mixed venous return.
    • Be able to reason through a combined data set (SpO2, PaO2, Hb concentration, PaCO2, pH, temperature, etc.) to identify obstructive vs restrictive patterns in PFTs and to predict disease states.
    • Remember the practical clinical scenarios and common pitfalls discussed in class (e.g., CO poisoning and SpO2 misreadings, the necessity for noninvasive vs invasive measurements, and the role of hyperbaric oxygen in CO toxicity).

Quick formulas and constants to memorize (as discussed in lecture)

  • Airway resistance formula:
    • R{air} = rac{P{IP} - P_{plat}}{Flow}
    • Normal range: 0.5 ext{ to } 2.5 rac{ ext{cmH}_2 ext{O}}{ ext{L s}}
  • Oxygen-carrying capacity per Hb molecule:
    • O2 ext{ per Hb} = 1.34 ext{ mL O}2/ ext{Hb molecule}
  • Hemoglobin reference values:
    • ext{Hb} ext{ normal}
      ightarrow 12 ext{ to } 16 ext{ g/dL}
  • General relationships to recall:
    • Major portion of transported O2 is bound to Hb (≈97%), with a small dissolved fraction (≈2–3%).
    • At SaO2 ≈ 90%, PaO2 ≈ 60 mmHg; at SaO2 ≈ 100%, PaO2 is ~100 mmHg under normal conditions.
    • Normal cardiac output: ≈ 5–8 L/min (can be higher in some patients).
    • The two components of oxygen delivery to tissues are Hb-bound O2 (via Hb) and dissolved O2 (in plasma).
    • The arterial-venous oxygen content difference (CaO2 − CvO2) represents tissue oxygen extraction; typical values reflect how much O2 is removed en route to tissues.

End of notes

  • Prepare to integrate these concepts during Monday’s review: we’ll cover specific pulmonary function interpretations and practice problems, then finalize a quick recap before the test a week from today.
  • If you’re feeling lost, reach out to the instructor early, review the PowerPoint illustrations for pulmonary functions, and revisit the basic physiology of oxygen transport and the dissociation curve to build confidence before the exam.