The first critical phase of postoperative care begins at the completion of the surgical procedure. During transfer from the operating room table to an intensive care unit (ICU) bed, from one monitoring system to another, and from the operating room to the ICU, the potential exists for airway and ventilation problems, sudden hypotension or hypertension, arrhythmias, increased mediastinal bleeding, inadvertent medication changes, and problems with invasive catheters and monitoring.
The electrocardiogram (ECG), arterial pressure tracing, and arterial oxygen saturation (SaO2) are transduced on the transport monitor, after which the patient is transferred to the ICU bed. During this transfer, the anesthesia team should coordinate all movements, paying particular attention to the airway, with hand ventilation provided by an Ambu bag connected to a portable oxygen tank. The entire team should also pay attention to invasive lines, the pacing wires, urinary catheter, and chest tubes to make sure nothing becomes dislodged during transfer.
Drug infusions should be placed on battery‐powered infusion pumps to ensure accurate infusion rates. These pumps should be plugged in during the surgical procedure so that battery function is fully charged when ready for transport. A selection of cardiac medications should always be available in the event of an emergency during transport.
A standard handoff routine from the anesthesiology team and accompanying providers to the ICU team (nurses, mid‐level providers and/or physicians, respiratory therapists) is essential to ensure an expeditious and safe arrival in the ICU.1
Upon arrival in the ICU, the endotracheal tube is connected to a mechanical ventilator, and the ECG, pressure monitoring lines, and pulse oximetry are transduced on a bedside monitor. Some hospitals have transport modules that plug directly into the ICU monitoring systems. Medication drip rates are confirmed or readjusted on controlled infusion pumps, preferably using the same pumps that were used in the operating room to avoid temporary disconnection from the patient. The thoracic drainage system is connected to suction.2
During this transition phase, much attention is directed to getting the patient connected to the monitors and attached to the ventilator. To ensure that the patient remains stable while getting settled in, it is critical that the accompanying anesthesia and/or surgical personnel as well as the accepting nurses and respiratory therapists make sure that:
The patient is being well ventilated by observing chest movement, auscultating bilateral breath sounds, and confirming that the oxygen saturation by pulse oximetry is acceptable (>90%).
The ECG tracing demonstrates satisfactory rate and rhythm on the transport and then the bedside monitor.
The blood pressure is adequate on the portable monitor and remains so after the arterial line is transduced and calibrated on the bedside monitor.
Immediate assessment and response to any abnormalities suspected to be present at the time of admission to the ICU, whether real or spurious, is imperative. The two most common problems encountered are a low blood pressure and an indecipherable ECG.
Low blood pressure (systolic BP <90 mm Hg or mean BP <60 mm Hg) is caused most commonly by hypovolemia or sudden termination of a drug infusion. However, the possibility of a more critical problem, such as acute blood loss, myocardial ischemia, severe myocardial dysfunction, arrhythmias, or ventilatory problems, should always be kept in mind. Low blood pressure may also result from inadequate zeroing of the transducer, or kinking or transient occlusion of the arterial line, producing a dampened tracing. If the transduced blood pressure is low, do the following:
Resume manual ventilation and listen for bilateral breath sounds.
Palpate the brachial or femoral artery to confirm a pulse and a satisfactory blood pressure. Attach the blood pressure cuff above the radial arterial line site and take an auscultatory or occlusion blood pressure. The latter is done by inflating the cuff until the arterial tracing on the monitor is obliterated; when the pressure tracing reappears, the systolic pressure can be read from the sphygmomanometer. Never assume that a low blood pressure recording is caused by dampening of the arterial line unless a higher pressure can be confirmed by another method. Insertion of an additional arterial monitoring line (usually in the femoral artery) may be indicated.
Make sure that all medication bottles are appropriately labeled and are connected to the patient and infusing at the designated rate through patent intravenous (IV) lines. Note: If hypotension is present, quickly ascertain whether the patient is receiving nitroglycerin or nitroprusside (in the silver wrapper), because both can lower the blood pressure precipitously. Unless you know how to change the drip rate on the particular drug infusion pump, let someone else who is familiar with it take care of it!
Quickly examine the chest tubes for massive mediastinal bleeding. Exsanguinating hemorrhage may require emergency sternotomy.
Evaluate the cardiac filling pressures on the ICU monitor. Confirm that the transducers are at the appropriate levels relative to the patient’s position in the bed and that the monitors are calibrated. Not uncommonly, during the very early stages of admission to the ICU, the observed filling pressures will not be accurate and this may confound an assessment of the patient’s volume status. The anesthesiologist should be aware of the filling pressures just prior to transport and can assist in assessing whether a significant change has occurred, with low filling pressures indicating hypovolemia and very high filling pressures consistent with myocardial dysfunction, excessive fluid administration, or tamponade.
The initial treatment of hypotension should include volume infusion, and, if there is no immediate response, administration of calcium chloride 500 mg IV. Vasoactive medications may be started or the rate of medications already being used can be adjusted. If there is no response to these measures, and the ECG is abnormal, assume the worst and prepare to treat the patient as an imminent cardiac arrest until the problem is sorted out. If the patient cannot be immediately resuscitated, call for help and prepare for an emergency sternotomy.
An indeterminate or undecipherable ECG is usually caused by artifact with jostling or detachment of the ECG leads. If the arterial waveform and pulse oximetry readings are acceptable, this is usually the case. However, if the arterial pressure is low or not transduced, the pulse is irregular or slow, or the monitor is difficult to interpret, palpate for a pulse and take the steps mentioned above. If the blood pressure is undetectable and an ECG reading is not available, assume the worst and treat the patient as a cardiac arrest. Readjust the ECG leads on the patient and monitor. If interpretation remains difficult, attach a standard ECG machine to limb leads to ascertain the rhythm.
If ventricular fibrillation or tachycardia is present, immediate defibrillation and a cardiac arrest protocol are indicated (see pages 591–599).
If a pacemaker is being used, examine the connections and settings and confirm capture on the bedside monitor or an ECG. Make sure that the pacemaker is appropriately sensing the patient’s rhythm, since inappropriate sensing may trigger malignant ventricular arrhythmias.
Attach a pacemaker and initiate pacing if bradycardia or heart block is present. The initial default setting on most external pacemakers is the VVI mode, which should produce a ventricular contraction. One should then attempt to pace the atrium (AOO) or initiate AV pacing (DDD or DVI) if atrial pacing wires are present and heart block is present. If there is no response to atrial pacing, ventricular pacing (VVI) should be used. If the patient has a rhythm, but the ventricle fails to pace, reverse the leads in the cable connector, and if that fails, consider placing a skin wire as a ground in case one of the wires has been dislodged from the heart. One of the atrial leads can also be used as the grounding wire (the anode or positive lead, which is the red connector on the pacing cables).
Look for the undetected development of atrial fibrillation that can develop during AV pacing. This may account for a fall in cardiac output and blood pressure, despite an adequate ventricular pacing rate.
Obtain a 12‐lead ECG, looking for evidence of arrhythmias or ischemia that may require treatment.
Once the patient’s heart rate, rhythm, and blood pressure are found to be satisfactory and adequate oxygenation and ventilation from the ventilator are confirmed, a full report should be given to the ICU staff by the accompanying anesthesiologist/CRNA and/or surgical house staff/PA/NP. This should include the patient’s cardiac disease and comorbidities, the operative procedure and any technical issues, the aortic cross‐clamp time and duration of cardiopulmonary bypass, medications used to come off bypass and those currently being administered, use of pacing, and special instructions for postoperative care.1 Further assessment as delineated in Table 7.1 can then be carried out to address the subtleties of patient care. A standardized set of preprinted orders that can be adapted to each patient is invaluable in ensuring that no essential elements of the early postoperative care are overlooked (Table 7.2 and Appendix 4). In most hospitals, this is incorporated into a set of electronic orders which must be individualized for each patient.
It is very important to review the immediate postoperative chest x‐ray to assess the position of the endotracheal tube and make sure that a pneumothorax is not missed. If present, an additional chest tube may need to be placed. Obtaining a chest x‐ray prior to departure from the operating room is beneficial. However, even if the initial chest x‐ray does not show a pneumothorax, one may develop subsequently, usually due to positive pressure ventilation, and is often manifested by unexplained hypoxemia or unstable hemodynamics without evident cause. In addition, review of an ECG obtained soon after arrival in the ICU is essential to identify any ischemic changes that might require urgent attention.
Table 7.1 Initial Evaluation of the Patient in the Intensive Care Unit
The patient should be examined thoroughly (heart, lungs, peripheral perfusion).
Obtain hemodynamic measurements, including the central venous pressure (CVP) and PA pressures; obtain a cardiac output and calculate the systemic vascular resistance (SVR) (see Table 11.1, page 517).
A portable supine chest x‐ray should be obtained either in the operating room or soon after arrival in the ICU. Specific attention should be paid to the position of the endotracheal tube and Swan‐Ganz catheter, the width of the mediastinum, and the presence of a pneumothorax, fluid overload, atelectasis, or pleural effusion (hemothorax).
A 12‐lead ECG should be reviewed for ischemic changes or arrhythmias.
Laboratory tests should be drawn (see Table 7.2 for sample admission order sheet).
Oxycodone with acetaminophen (Percocet) 5/325 mg 1–2 tabs PO q4h prn for pain after extubation; start with 1 tab for mild pain (1–3 on pain scale); give additional tab 60 minutes later if no change in pain. Give 2 tabs for moderate–severe pain (4–10 on pain scale)
β‐blocker starting at 8:00 AM on POD #1, then q12h; hold for HR <60 or SBP <100
Metoprolol _____ mg PO/per NG tube bid (12.5–100 mg bid)
Carvedilol _____ mg PO/per NG tube bid (3.125–25 mg bid)
Amiodarone 400 mg PO bid to start after amiodarone infusion discontinued
Magnesium sulfate 2 g in 50 mL NS IV over 2 hours on POD #1 in AM
Sucralfate 1 g per NG tube q6h until NG tube removed
Pantoprazole (Protonix) 40 mg IV/PO qd
Aspirin◻ 81 mg◻ 325 mg PO qd (starting 8 hours after arrival); hold for platelet count <60,000 or chest tube drainage >50 mL/h
Warfarin _____ mg starting _____; check with HO for daily dose (use warfarin protocol) (see Appendix 8)
Ascorbic acid 1 g PO qd × 5 days
Nitroglycerin 50 mg/250 mL D5W at 10–15 μg/min until taking PO (radial artery prophylaxis); then convert to:
Amlodipine 5 mg PO qd ◻ Amlodipine 10 mg PO qd
Isosorbide mononitrate sustained release (Imdur) 20 mg PO qd
Simvastatin ____ mg qd hs (no more than 20 mg if on amiodarone)
Mupirocin 2% (Bactroban ointment) via Q‐tip nasal swab the evening after surgery and bid × 3 days
Chlorhexidine 0.12% oral wash (Peridex) 15 mL soft swab and rub oral cavity while intubated q12h
Acetaminophen 650 mg PO/PR q4h prn temp >38.5 °C
Metoclopramide 10 mg IV/PO q6h prn nausea
Ondansetron 4–8 mg IV q4h prn nausea
KCl 20 mEq/50 mL D5W via central line to keep K+ >4.5 mEq/L:
KCl 10 mEq over 30 min for K+ 4.0–4.5
KCl 20 mEq over 60 min for K+ 3.5–3.9
KCl 40 mEq over 90 min for K+ <3.5
Initiate hyperglycemia protocol if blood glucose >150 mg/dL on admission or any time within the first 48 hours (see Appendix 6)
II. Monitoring in the ICU: Techniques and Problems
Careful monitoring is required in the early postoperative period to optimize patient management and outcome.2 A continuous display of the ECG is provided, and pressures derived from invasive catheters, including arterial and Swan‐Ganz catheters placed in the operating room, are transduced on bedside monitors (Figure 7.1). The endotracheal tube is securely connected to the mechanical ventilator and appropriate ventilator settings are selected. A continuous readout of the arterial oxygen saturation (SaO2) determined by pulse oximetry should be displayed. The drainage outputs of chest tubes and the Foley catheter are measured and recorded. Conscientious data collection on computerized flowsheets is essential. Each invasive technique is used to provide an essential function or obtain special information about the patient’s postoperative course, but each has potential complications. Each should be used only as long as necessary to maximize benefit while minimizing morbidity.
ECG display on a bedside monitor is critical to allow for rapid interpretation of rhythm changes. Most bedside monitors have a memory, and abnormal rhythms will activate a printout. This is helpful in detecting the mechanism of arrhythmia development (such as an R‐on‐T phenomenon leading to ventricular tachycardia or fibrillation). ST segment analysis is provided by most monitoring systems, but abnormalities must be thoroughly analyzed from a 12‐lead ECG.
Mechanical ventilation via an endotracheal tube is used for all patients, except those who are extubated in the operating room. The initial settings are determined by the anesthesiologist and respiratory therapist and generally provide a tidal volume around 6–8 mL/kg at a rate of 12–14/min with the initial FiO2 set at 1.0. Confirmation of bilateral breath sounds and chest movement, intermittent rechecking of ventilator settings, and assessment of the adequacy of gas exchange are essential.
Pulse oximetry is routinely used to continuously assess the status of peripheral perfusion and arterial oxygen saturation (SaO2).3 It can draw attention to major problems with oxygenation during the period of intubation and following extubation. If the patient is severely vasoconstricted, the recordings from the patient’s fingers may be inadequate and a better signal may be derived from the earlobe. Use of pulse oximetry obviates the need to draw arterial blood gases (ABGs) more than a few times during the period of intubation.4 Nonetheless, it should be kept in mind that pulse oximetry only provides a measurement of SaO2 (and heart rate), but it does not provide the same information as an ABG, which measures the PCO2 and pH. These values may be important in assessing the patient’s respiratory drive during the weaning process and can identify whether the patient has a metabolic or respiratory acidosis/alkalosis. This is particularly valuable in identifying a metabolic acidosis that may reflect borderline hemodynamic function that requires further pharmacologic intervention. A profound metabolic acidosis often suggests the presence of a catastrophic problem, such as mesenteric ischemia.
Suctioning should be performed gently every few hours or as necessary to maintain a tube free of secretions but not so frequently as to induce endobronchial trauma or bronchospasm.5 The endotracheal tube bypasses the protective mechanism of the upper airway and predisposes the patient to pulmonary infection. It should be removed as soon as the patient can maintain satisfactory ventilation and oxygenation and is able to protect their airway. This is generally accomplished within 4–6 hours of surgery. A standard protocol for weaning and extubation is essential in any cardiac surgical ICU (see Tables 10.3–10.5, pages 475–476).
Arterial lines are placed in either the radial or femoral artery during surgery and are transduced on the bedside monitor.6
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