A primer for the student joining the adult cardiac surgery service tomorrow: Primer 1 of 7.

Central MessageJTCVS has partnered with the TSRA & TSMA to make a 7-part primer series introducing medical students to CT Surgery. This, the first installment, focuses on excelling in the Adult Cardiac Surgery rotation.See Commentary on page XXX. JTCVS has partnered with the TSRA & TSMA to make a 7-part primer series introducing medical students to CT Surgery. This, the first installment, focuses on excelling in the Adult Cardiac Surgery rotation. See Commentary on page XXX. The adult cardiac surgery service often manages some of the sickest patients in the hospital. This can be a very fast-paced environment with a lot of new information to take in. This primer discusses the nuts and bolts of being on the adult cardiac surgery service, separated into 3 phases of care: preoperative (clinic and consults), intraoperative, and postoperative (patient management). Below is a brief outline of what a typical day on an adult cardiac surgery service will look like (this is variable by institution, so check with the residents, fellows, and/or attendings). It is recommended that all students contact the senior resident/fellow on the service to know when the team will round and what responsibilities the student should expect. 5:30 AM – Pre-round (as needed). 6:00 AM – Rounding begins with the students, residents, fellows, and overnight intensive care unit (ICU) providers. 7:30 AM – Operating rooms (ORs) begin cases or clinic day begins. 12:30 PM – Case 1 concludes; now is a good time to eat something, read up on the next case, and study. 1:30 PM – Case 2 starts. 6:30 PM – Case 2 ends. 7:00 PM – Go home. New clinic patients and inpatient consults are very similar in terms of what to look for and what to ask during a history and physical. Below is a walk-through of what to look for and why each parameter is important. Before seeing the patient, it is good to review the relevant clinical data including the medical and surgical history. For the most part, by the time the cardiac surgery service is consulted or a patient is seen in the clinic, the history and tentative plan have been established by the referring cardiologist. As such, talking with the patient is mostly to confirm what has already been established in the chart, discuss what the patient knows about their disease state and why they are seeing a cardiac surgeon, and to go over treatment options. That said, while cardiology may have performed a suitable workup, remember that the surgeon is the one making incision on the patient and, as such, the surgeon and their trainees should approach each patient as if they have not been worked up by anybody else, searching for new and relevant information. Note that patients transferred from another institution may require a more aggressive approach to make sure outside imaging is available, old operative reports are obtained, and to reconfirm that the correct diagnosis has been made. Important clinic and consult parameters are listed in Table 1.1Online STS risk calculator.https://riskcalc.sts.org/stswebriskcalc/Date accessed: March 19, 2023Google Scholar,2Bojar R.M. Manual of Perioperative Care in Adult Cardiac Surgery. Wiley Blackwell, 2021Crossref Google ScholarTable 1Clinic and consult important parametersParameterAbbreviationNotesBefore seeing the patient Referring service/cardiologist–Often, an attending will want to know what service is referring the patient (inpatient) or what cardiologist/primary care doctor referred the patient to the clinic (outpatient). History of present illnessHPIA focused history on when/why the disease was discovered, follow-up since discovery, and relevant symptoms (including progression of symptoms).More about common pathologies and presentations can be found in the operative portion of this text. Past medical historyPMHConsider comorbidities that relate to cardiac pathology or increase surgical risk.Things to think about include general cardiovascular risk factors such as diabetes, hypertension, hyperlipidemia, peripheral artery disease, immunocompromised state, renal disease, liver disease, cerebrovascular disease, cancer within the past 5 y, mediastinal radiation, sleep apnea, syncope, lung disease, heart disease (previous myocardial infarction, aortic stenosis, arrhythmia, endocarditis, etc), and issues with anesthesia. Past surgical historyPSHIt is important to review any relevant surgical history, including any history of previous chest instrumentation, previous cardiac surgery (for which previous operative notes should be obtained), and previous cardiology procedures such as alcohol septal ablation, PCI, PFO closure, LAA closure, TEE cardioversions, TAVR, mitral valve clipping, etc. Current medicationsMedsList current medications and get a detailed history on any cardiovascular-related medications. Note that what is listed in the chart is not always what the patient is actually taking or how frequently they are taking it.Often, the most important medications to discuss with the patient are NOACs, clopidogrel, warfarin, and other anticoagulants as well as when these medications were discontinued. Patients may not know their specific medications, however, they will generally know if they are taking “blood thinners” and/or when they discontinued “blood thinners.” Labs–Review labs with a focus on CBC, CMP, coagulation studies, ABGs, etc. ElectrocardiogramECG/EKGReview for irregularities. Note any history of heart block, as this could increase the risk of permanent pacemaker insertion post-operatively. If you are having trouble with interpretation, look for the cardiology official report on the EKG, if available.A more detailed review of EKGs can be found at the following links:https://www.ncbi.nlm.nih.gov/books/NBK549803/https://www.amboss.com/us/knowledge/ECG/ EchocardiographyTransthoracic echocardiographyTransesophageal echocardiographyEchoTTE/TEEEchocardiography is a key dynamic imaging tool used to assess global cardiac function, valvular pathology, and plan for surgical intervention. This modality depicts how the heart is functioning in every chamber (including valves) and measures overall left and right heart function (ejection fraction). Various measurements including heart size, degree of valvular regurgitation or stenosis, and heart function can be obtained quantitatively and qualitatively. Often, you may need to refer to the official report to more clearly understand how each part of the heart is functioning.A more detailed review of echocardiography is covered in the fourth primer within this series, “A Primer for Students Regarding Cardiothoracic Imaging.” In addition, students who are interested in gaining a clearer understanding of the 3-dimensional structures visualized with echo may navigate to the following links:TEE: http://pie.med.utoronto.ca/tee/TTE: http://pie.med.utoronto.ca/tte/TTE_content/standardviews.html Cardiac catheterizationCathThis invasive study is divided into left and right heart catheterization. The left heart catheterization is a coronary angiogram allowing clinicians to obtain high-resolution views of the intraluminal architecture of the coronary arteries. This imaging may elucidate the need to intervene and to revascularize the coronary artery in question. LV function can also be grossly assessed via a ventriculogram.The right heart catheterization provides specific intracardiac and intravascular pressure measurements that allows for calculations of pulmonary vascular resistance, cardiac output, cardiac index, and wedge pressure (left atrial pressure via distal pulmonary artery catheter wedge). It is a critical component of heart failure management and helps guide decision making for volume status, diuretics, need for mechanical support, and type of circulatory support (LV, RV, or BiV support). Should patients require a continuous assessment of the above such as in cardiogenic shock, a PA catheter is left in via central vein access for adequate diuresis and cardiac pharmacological titration of medications. This catheter is known as a Swan–Ganz catheter (Edwards Lifesciences).Both echocardiography and catheterization are quite difficult to master interpreting, but reading the report will at least summarize the most relevant information. It is always beneficial to open the imaging first and correlate what is seen on the report.A more detailed review of cardiac catheterization is covered in the fourth primer within this series, “A Primer for Students Regarding Cardiothoracic Imaging.” Chest radiographCXRThe patient may have a CXR. CXRs can detect disease of thoracic structures (lung, heart, pleura, spine, diaphragm, etc) and are standard practice before most operations. It is important to compare the preoperative and immediate postoperative CXR to assess placement of new catheters, drains, breathing tubes, and lung parenchyma, given the need to wean mechanical ventilation. In addition, one can assess for injury to other structures that have occurred (eg, phrenic nerve resulting in hemidiaphragm paralysis/elevation). One may look for pulmonary edema, pleural effusions, widened mediastinum, infiltrates, pneumothorax, and other findings. A more extensive discussion (with illustrations) of cardiothoracic imaging can be found later in this primer series in the Cardiothoracic Imaging primer.Note that some patients have dozens of previous imaging studies, and it isn’t necessary to look at every one. Try looking at the most recent one or two and compare them with additional imaging to help with preoperative planning.After assessing the aforementioned information, it is often possible to piece together most of the assessment and plan. It is best to know as much as possible about a patient and the potential plans for treatment before speaking with them. The next step is to speak with the patient.Talking to your patient Chief complaintCCConsider why the patient has come to clinic or why the cardiac surgery team has been consulted (this is often due to a symptom). Common examples include, chest pain, shortness of breath, fatigue, syncope, lower extremity swelling, etc.Ask the patient what specifically brought them into the hospital/clinic. This could include symptoms related to the cardiac problem, test results prompting admission (eg, critical disease on left heart catheterization), or some other complaint for which cardiac disease was incidentally found. Importantly, it is important to understand when the symptoms began and when/how they have worsened to the point of hospitalization. Seek to identify if this was a process which took days, weeks, months, or years to progress. HPI, PMH, Meds–Acquire and correlate the information in the chart and the interview of the patient or historian Review of systemsROSThis is often part of the HPI but can be expanded into its own section for symptoms that are likely unrelated to the presenting cardiac pathology (eg, chronic eczema). Surgical history–Any previous surgeries, regardless of time since surgery. In particular, a cardiac surgery history will have strong influence for a cardiac surgical plan and must be closely considered. One must exhaust all efforts to acquire all original cardiac operative reports for size of valve, previously bypassed vessels, and CT imaging to confirm patient anatomy in light of previous surgery. Family historyFHxHistory of heart disease.History of premature heart disease (direct blood relatives <55 y in a male patient, <65 y in a female patient).Cancer.Issues with anesthesia in the past. Social and occupational history–What does the patient do on a daily basis and how is this disease pathology impacting their daily life? This is important because most surgeons only operate to treat symptoms or prolong life, that is, to improve quality or length of life.Ascertain alcohol use, smoking history, and other drug use.Are there risk factors in the patient’s occupation that could change decision making (eg, they work in construction and are prone to cutting themselves and want to avoid long term anticoagulation)?Who is at home to help take care of this patient if needed? Other questions to ask–What is the patient’s understanding of their disease process?What is the patient’s understanding of treatment options?Is surgery something the patient is open to?Does the patient plan to become pregnant (this can impact whether or not surgical options requiring anticoagulation can be considered)?Physical examinationThe physical examination is primarily focused on the cardiovascular and pulmonary systems. OverallDoes the patient look comfortable, uncomfortable, or in significant distress? CardiacAuscultate cardiac listening areas and assess for murmurs. Assess distal pulses for discrepancy that might suggest peripheral vascular disease. RespiratoryAuscultate and assess for decreased breath sounds at the bases or crackles that could suggest pleural effusions or pulmonary edema, respectively. SkinLook for evidence of lower extremity edema (heart failure), classical endocarditis signs (if relevant), signs of previous surgery (scars), etc.The following examinations are important, but should be done in a concise format (eg, it is unnecessary to conduct a complete neurologic examination in most patients). Body mass index/weightUsually entered at time of admission. In postoperative patients, tracking a patient’s weight is a useful tool in assessing fluid balance and effects of diuresis. NeurologicIs the patient alert and oriented? Are there any gross deficiencies of strength or facial drooping? Are there any signs of previous stroke or TIA? MusculoskeletalDoes the patient have any gross motor abnormalities? AbdominalInspection, auscultation, and palpation of the abdomen is usually sufficient.Assessment and planCombine the aforementioned information to decide what treatment options are most appropriate for the patient.It is very important to look at formal indications for performing/not performing a certain operation. Formal indications are more comprehensively covered in the Operations portion of this text.Calculate the STS Risk Score (this can be found at https://riskcalc.sts.org/stswebriskcalc/calculate).1Online STS risk calculator.https://riskcalc.sts.org/stswebriskcalc/Date accessed: March 19, 2023Google ScholarPresentation to resident/attendingSee an example presentation following the table.Final stepsThis comes after presenting and finalizing whether the patient will receive an operation or not.•Patient is not having surgery: Schedule follow-up as indicated. Should additional testing or surveillance be indicated, appropriate follow-up with cardiac surgery, cardiology, and/or the primary care provider should be set up in advance.•Patient is having surgery: Complete any of the following that have not been completed (this is institution specific, but an example workup is provided below). Cardiac catheterizationA cardiac cath/coronary angiogram is important in all patients older than 40 years old considering heart surgery. Understanding coronary anatomy is important for specific valvular operations and CABG can be added on to the primary operation if the patient has moderate atherosclerotic disease and is having heart surgery for another reason (eg, valve replacement). Vein mapping (pending cath) - optionalIf the cath reveals indication for coronary artery bypass graft, it may be useful to map the veins (specifically the saphenous veins) to ensure they are physically present and viable for grafting. This test is optional and may be more useful in patients with peripheral vascular disease who may have had a saphenous vein used as a conduit for a prior operation. EchocardiogramAs discussed previously, this imaging modality characterizes wall motion abnormalities, valve function, and overall heart function. CXRObtain if not already obtained. Relevance of CXR discussed previously in this table. Pulmonary function tests (PFTs)Assesses for chronic pulmonary disease (included in STS Risk Score). Note that studies have shown that poor pulmonary function can increase the risk of postoperative morbidity and prolonged ventilation.Note that PFTs are not necessary without underlying lung disease or symptoms of respiratory limitations. Ankle-brachial indicesAssesses for peripheral vascular disease (included in the STS Risk Score). Carotid Doppler - optionalAssesses for carotid artery stenosis (included in the STS Risk Score), given its risk for stroke. Carotid artery disease may also assist the surgeon regarding preferential hemodynamics during cardiopulmonary bypass to assure cerebral perfusion.This test is optional and often low yield in patients without bruits, symptoms of carotid disease, or left main coronary artery disease. From a perspective of systems-based practice, it is important not to order unnecessary expensive tests. Discussion with the attending surgeon on what tests are essential may be beneficial. LabworkCBC (with differential if concern for infection at admission)CMP (includes glucose, Ca, Na, K, HCO3, Cl, albumin, protein, alkaline phosphatase, ALT, AST, bilirubin, BUN, and Cr)Coagulation Studies (often includes platelets (in CBC), PT/INR, PTT, and fibrinogen)UrinalysisMRSA swab Medication changesThe patient may be asked to discontinue (“hold”) certain medications the day of surgery and/or days before surgery. Common examples are as follows2Bojar R.M. Manual of Perioperative Care in Adult Cardiac Surgery. Wiley Blackwell, 2021Crossref Google Scholar:Discontinue 7 d before surgery: prasugrelDiscontinue 5 d before surgery: clopidogrel, ticagrelor, warfarinDiscontinue 60 h before surgery: fondaparinuxDiscontinue 48 h before surgery: NOACs (dabigatran, apixaban, rivaroxaban, edoxaban)Discontinue 24 h before surgery: abciximab, low molecular weight heparin (LMWH)Discontinue 4 h before surgery: unfractionated heparin, tirofiban, eptifibatideDiscontinue 1-2 h before to surgery: bivalirudinDiscontinue morning of surgery: ACEi/ARB (refractory hypotension/vasoplegia), diabetic medications, diuretics Oral examinationAortic or valve procedures that involve implantation of a prosthetic device usually require an oral examination. If the patient has oral pain, redness, rotten teeth, or other cause for concern, formal dental clearance may be considered.PCI, Percutaneous coronary intervention; PFO, patent foramen ovale; LAA, left atrial appendage; TAVR, transcatheter aortic valve replacement; NOACs, non-vitamin K antagonist oral anticoagulants; CBC, complete blood count; CMP, comprehensive metabolic panel; ABG, arterial blood gas; LV, left ventricle; RV, right ventricle; BiV, biventricular; PA, pulmonary artery; CT, computed tomography; TIA, transient ischemic attack; STS, Society of Thoracic Surgeons; Ca, calcium; Na, sodium; K, potassium; HCO3, bicarbonate; Cl, chloride; ALT, alanine aminotransferase; AST, aspartate aminotransferase; BUN, blood urea nitrogen; Cr, creatinine; PT, prothrombin time; INR, international normalized ratio; PTT, partial thromboplastin time; MRSA, methicillin-resistant Staphylococcus aureus; ACEi/ARB, angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker. Open table in a new tab PCI, Percutaneous coronary intervention; PFO, patent foramen ovale; LAA, left atrial appendage; TAVR, transcatheter aortic valve replacement; NOACs, non-vitamin K antagonist oral anticoagulants; CBC, complete blood count; CMP, comprehensive metabolic panel; ABG, arterial blood gas; LV, left ventricle; RV, right ventricle; BiV, biventricular; PA, pulmonary artery; CT, computed tomography; TIA, transient ischemic attack; STS, Society of Thoracic Surgeons; Ca, calcium; Na, sodium; K, potassium; HCO3, bicarbonate; Cl, chloride; ALT, alanine aminotransferase; AST, aspartate aminotransferase; BUN, blood urea nitrogen; Cr, creatinine; PT, prothrombin time; INR, international normalized ratio; PTT, partial thromboplastin time; MRSA, methicillin-resistant Staphylococcus aureus; ACEi/ARB, angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker. After gathering all of the data and seeing the patient, the next step is to present to a resident or attending. The key, as with rounds, is to be concise while giving all of the pertinent information. This can be challenging, so an example is provided to follow: Mr Jones is a 63-year-old male with a history of hypertension and hyperlipidemia who presents to Dr Knight’s clinic for evaluation of aortic stenosis (AS). The patient was found to have a murmur by his primary care provider in 2014, which was evaluated by echocardiography at that time and found to be mild AS. The patient was asymptomatic in 2014 and follows up regularly with cardiology. At his last visit to cardiology in March of 2022, the patient reported dyspnea on exertion and a syncopal event. An echo was performed that showed severe AS with a mean pressure gradient of 47 mm Hg, aortic valve area 0.6 cm2, and a peak velocity of 5.1 m/s. Mr Jones’ cardiologist, Dr Harb, referred him to our clinic for consideration of aortic valve replacement. Mr Jones and his wife understand the progressive nature of this disease and would like to move forward with surgical aortic valve replacement. They recognize transcatheter aortic valve replacement (TAVR) as an option, although they prefer to proceed with surgery. I recommend we use a mechanical valve, given the longevity of the valve, although we will have to discuss valve options with our patient. Given Mr Jones’ severe, symptomatic AS, this is stage D1 disease, which has a class 1 indication for aortic valve replacement. The calculated Society of Thoracic Surgeons risk of mortality is less than 1%. I believe it is appropriate to proceed with surgery. Next, look at the “Final Steps” portion of Table 1. After completing those tasks, the clinic visit or consult is complete. Unlike most surgical services, early postoperative patients on the cardiac surgery service are typically managed in an ICU opposed to a typical hospital floor. This makes pre-rounding and rounding 2 more involved than on most other services. The first step is to simply ask the residents, nurse practitioners, or physician assistants if there is a template note that is commonly used. If not, it is appropriate to free hand the sections to follow into history of present illness, laboratory values, physical examination, etc. It may be easiest to write everything in a note format upfront rather than gathering all the data in one place and having to translate it to a note later on. To follow is a list of clinical data and information which is important to consider in every patient. In general, check over all of the patient’s clinical data, but focus on the following. Important parameters in postoperative management of the adult cardiac surgery patient are listed in Table 2.3Merck Manuals Global medical knowledge 2022. 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Reference intervals for venous blood gas measurement in adults.Clin Chem Lab Med. 2020; 59: 947-954https://doi.org/10.1515/cclm-2020-1224Crossref PubMed Scopus (5) Google Scholar, 17Castro D. Patil S.M. Keenaghan M. Arterial blood gas.in: StatPearls [internet]. StatPearls Publishing, 2022Google Scholar,18Tillquist M.N. Maddox T.M. Cardiac crossroads: deciding between mechanical or bioprosthetic heart valve replacement.Patient Prefer Adherence. 2011; 5: 91-99Crossref PubMed Scopus (79) Google ScholarTable 2Important parameters in the postoperative management of the adult cardiac surgery patientParameterAbbreviationNormal valuesNotesGeneral/vitals Postoperative dayPOD-Know what day the patient is postoperatively (POD 0 is the day of surgery, POD 1 is the day after surgery, etc). Blood pressureBP120/80 mm Hg (highly variable)3Merck Manuals Global medical knowledge 2022. [internet].https://www.merckmanuals.com/professional/resourcespages/global-medical-knowledgeDate accessed: March 19, 2023Google ScholarKnow whether the patient is on any vasoactive/inotropic medications (eg, epinephrine, norepinephrine, milrinone, phenylephrine). Any patient on these medications generally should have an arterial line for continuous BP monitoring. Heart rateHR60-100 beats per minute4Sapra A. Malik A. Bhandari P. Vital sign assessment.in: StatPearls [internet]. StatPearls Publishing, 2022Google ScholarKnow if the patient has a permanent pacemaker or temporary pacing wires that were put in during the operation. For example, patients may be AV-paced at 60, or A-paced at 80 depending on surgeon preference.AV-paced means pacing stimulus delivered to both the atrial and ventricles, using separate atrial and ventricular wires. A-paced means the patient is being paced only with an atrial wire, and may or may not have an additional ventricular wire (that is not being used). A-pacing is critical for patients dependent on atrial kick who have a competent AV node with AV synchrony.Check the electrocardiogram (ECG/EKG) and compare it with previous ones (especially important following CABG surgery) to assess for arrhythmias, new ST elevations, bundle branch blocks, or evidence of repolarization abnormalities suggestive of reperfusion injury. Respiratory rate (RR)/saturation of oxygenRR/Spo212-20 breaths per minute4Sapra A. Malik A. Bhandari P. Vital sign assessment.in: StatPearls [internet]. StatPearls Publishing, 2022Google Scholar>95% Spo25Hafen B.B. Sharma S. Oxygen saturation.in: StatPearls [Internet]. StatPearls Publishing, 2022Google ScholarThe patient’s breathing may be supported by a ventilator, nasal cannula, etc. Know which, if any, of these are being used, and to what extent they are being used (eg, how many liters of air is the patient on if they are using a nasal cannula). VentilatorVentInitial vent settings2Bojar R.M. Manual of Perioperative Care in Adult Cardiac Surgery. Wiley Blackwell, 2021Crossref Google ScholarFio2: 0.4 (if >95% Spo2 on 1.0)PEEP: 5 cm H2ORR: 10-12 breaths/minVt: 6-8 mL/kgKnow if the patient is on a ventilator and, if so, what the Fio2, positive end expiratory pressure (PEEP), tidal volume (Vt), and respiratory rate (RR) are set to. Vents can be set to various modes.Volume-limited mode: Vent delivers a preset tidal volume.Assist control (A/C): If a patient initiates a respiratory effort, the vent will deliver a preset tidal volume. The vent will also deliver a preset tidal volume at preset intervals if no breath is attempted by the patient.There are many more vent settings beyond the scope of this text.Alter Pao2: Reduce Pao2 via reducing Fio2 or PEEP. Increase Pao2 via increasing Fio2or PEEP.Alter Paco2: Reduce Paco2 via increasing RR or tidal volume (Vt). Increase Paco2 via reducing RR or Vt.Providers in the ICU will often discuss weaning patients off ventilators in multiple ways.“Spontaneous breathing trial” means testing to see whether the patient is able to breathe with minimal vent support. This could be in the form of pressure support or CPAP, among others.“Pressure support” means the patient triggers each breath and the ventilator delivers minimal positive pressure (PEEP 5-8) to ease the work of breathing.“Trach collar” means that the patient is disconnected from the ventilator and allowed to breathe either room air or supplemental oxygen through a tracheostomy for a certain amount of time without ventilatory support—if the patient continues trach collaring indefinitely while remaining at an appropriate oxygenation status, they have been weaned off the ventilator. The team may opt to support the trach collaring with increased Fio2 air.Hemodynamics and mechanical circulatory support Central venous pressureCVP8-12 mm Hg6Shah P. Louis M.A. Physiology, central venous pressure.in: StatPearls [internet]. StatPearls Publishing, 2022Google ScholarDenotes the pressure in the right atrium and is a surrogate for right heart volume status. Pulmonary artery pressurePAPSystolic: 20 mm Hg7Institute of Medicine (US)Committee on Social Securit