Hypovolemic Shock

Hypovolemic Shock

John C. Klick

S. Michael Roberts

Ranjit Deshpande

Lyle Gerety

Jan Kasal

Chakradhar Venkata

1. You are called urgently to the postanesthesia care unit (PACU) to evaluate a 59-year-old male who arrived 15 minutes ago after undergoing a redo left total hip arthroplasty under general anesthesia. He appears comfortable but somnolent. He has no documented history of cardiovascular disease, but he is hypotensive with a noninvasive BP of 78/47 mm Hg. He does not have an arterial line. Estimated blood loss was approximately 1200 cc, and the resident reports that he was “well resuscitated” with a hemoglobin of 9.5 on his last blood gas 10 minutes ago. He made adequate urine in the operating room (OR) by report, and the PACU resident is now starting a phenylephrine drip. You perform a bedside ultrasound and the attached image is seen when visualizing the inferior vena cava (IVC). Left ventricular (LV) and right ventricular (RV) contractility appear hyperdynamic as shown in image Videos 41.1, 41.2, 41.3. Based on this scenario and your imaging, what would be the next logical step in the management of this patient?

A. Start norepinephrine

B. Start epinephrine

C. Administer a bolus of lactated Ringer’s

D. Give a unit of blood

View Answer

1. Correct Answer: C. Administer a bolus of lactated Ringer’s

Rationale: This patient has undergone a redo joint replacement surgery that can be associated with significant blood loss and hypovolemia. His LV and RV contractility are hyperdynamic, obviating any need for inotropic support such as epinephrine. The almost complete collapse of the IVC with resting tidal ventilation suggests a preload deficit. This patient needs volume, but the hemoglobin of 9.5 in a patient without active ischemia or any documented history of cardiovascular disease is not an indication for blood transfusion. A bolus of a balanced crystalloid such as lactated Ringer’s makes the most sense in this scenario.

Selected Reference

1. Boyd JH, Sirounis D, Maizel J, Slama M. Echocardiography as a guide to fluid management. Crit Care. 2016;20:274.

2. A 22-year-old female with a history of mitral valve prolapse is involved in a motorcycle accident in which she suffered a closed head injury and extremity fractures. She arrives at your intensive care unit (ICU) after open reduction and internal fixation (ORIF) of a femur fracture. She is in sinus tachycardia at 125 bpm with a systolic BP in the high 70s (mm Hg). The anesthesiologist mentions that the patient’s BP was difficult to control, requiring frequent phenylephrine boluses to which the patient would respond. There was relatively little blood loss so she did not receive much in the way of intravenous (IV) fluids. You are concerned by the BP lability and perform a bedside echocardiogram. Based on the image Video 41.4 obtained, what would be the next most appropriate step in the management of this patient?

A. Give fluid

B. Start epinephrine

C. Start milrinone

D. Insert an intra-aortic balloon pump (IABP)

View Answer

2. Correct Answer: A. Give fluid

Rationale: This patient has SAM of the mitral valve. While certain pathologies of the mitral valve predispose to SAM, anybody can develop it if hypovolemic enough and extremely hyperdynamic. Rather than closing appropriately in systole, the anterior leaflet of the mitral valve can get sucked into the LVOT and cause obstruction of the aortic outflow tract. The management consists of first giving fluid to allow the ventricle to expand in diastole. This way the anterior mitral leaflet will not be as close to the LVOT in the next systolic beat and less likely to get pulled into the LVOT. Other strategies are to administer beta-blockers and pure vasoconstrictors to make the ventricle less hyperdynamic and to create a higher afterload to prevent the anterior mitral leaflet from being sucked into the LVOT. Anything that decreases the LV afterload (such as an IABP) or increases the contractility of the ventricle (such as epinephrine and milrinone) can exacerbate SAM. The fact that this patient is developing SAM after a procedure with very little blood loss should prompt a search for another unrecognized source of bleeding.

Selected Reference

1. Kapoor MC. Systolic anterior motion of the mitral valve in hypovolemia and hyperadenergic states. Indian J Anaesth. 2014;58(1):7-8.

3. A 68-year-old male is recovering in the ICU after undergoing an uneventful five-vessel coronary artery bypass grafting (CABG) this morning. He remains intubated. Over the past hour, he has become progressively tachycardic and hypotensive to the point where the bedside nurse asks about starting a pressor agent. You are concerned and perform a bedside transthoracic echocardiography (TTE). Windows are limited after his sternotomy, so you decide to do a transesophageal echocardiography (TEE). image Video 41.5 is obtained. While the cardiac surgeon is being paged to the bedside, which of the following choices is most appropriate for the management of this patient?

A. Metoprolol to limit demand ischemia

B. Emergent extracorporeal membrane oxygenation (ECMO) cannulation

C. Start milrinone

D. Aggressive volume resuscitation

View Answer

3. Correct Answer: D. Aggressive volume resuscitation

Rationale: This patient has cardiac tamponade (focal to left atrium) after his open heart procedure. Unlike the generalized global effusion that is usually seen with “medical” pericardial tamponade, tamponade after cardiac surgery can often be a localized phenomenon and requires redo sternotomy. In the meantime, every effort needs to be made to maintain CO while preparing to open the chest. This means keeping the ventricles “full, fast and forward.” Aggressive volume resuscitation should commence to overcome the extrinsic pressure on the heart to allow it to fill, while a high HR will help maximize the limited CO. An epinephrine infusion would also help with contractility and increase HR. It is important to note that these are temporizing measures until the chest is reopened and the localized tamponade drained. Milrinone is not ideal in the setting of an acutely hypotensive patient, as it might worsen the hypotension. ECMO will not fix the underlying problem, while metoprolol may well result in cardiac arrest. TEE will be far more sensitive than TTE for the detection of a localized fluid collection after cardiac surgery.

Selected Reference

1. Khanna S, Maheshwari K. Hemopericardium and acute cardiac tamponade-images in anesthesiology. Anesthesiology. 2018;128:1006.

4. A 72-year-old woman in septic shock on norepinephrine after emergent surgery for a strangulated ventral hernia is intubated in your ICU. You have been steadily escalating the pressor dose and have given quite a bit of fluid to her throughout the day. She has a history of heart failure with preserved ejection fraction (HFpEF) and you are questioning whether additional fluid might help improve her hemodynamics. You are also concerned that additional fluid may push her into heart failure. Which of the following is most appropriate to determine if she will respond to additional IV fluid?

A. Transduce the central venous pressure (CVP) and administer fluid if CVP <15 mm Hg

B. Place a Swan-Ganz catheter and measure a pulmonary artery occlusion pressure (PAOP) to determine LV filling pressure

C. Use echo to determine her cardiac output (CO) and stroke volume (SV) then perform a passive leg raise (PLR) to look for an increase in SV

D. Use echo to measure IVC collapse with mechanical respiration

View Answer

4. Correct Answer: C. Use echo to determine her cardiac output (CO) and stroke volume (SV) then perform a passive leg raise (PLR) to look for an increase in SV

Rationale: Dynamic measures of volume responsiveness are far more accurate than static pressure-based readings, which have been demonstrated time and again to not correlate with volume responsiveness. Especially given the history of HFpEF, performing a PLR allows the autotransfusion of roughly 300 cc of blood into the right side of the heart. Measuring at least a 12% change in the SV or the LVOT VTI by echo is consistent with a patient who will respond to volume administration with an increase in the CO. Changes in IVC diameter as a measure of volume responsiveness have only been validated in the setting of independently breathing patients or patients who are paralyzed on mechanical ventilation with >8 cc/kg tidal volumes.

Selected Reference

1. Miller A, Mandeville J. Predicting and measuring fluid responsiveness with echocardiography. Echo Res Pract. 2016;3(2):G1-G12.

5. A 78-year-old male is in your ICU with presumed urosepsis from a urinary tract infection (UTI). The patient has had multiple past admissions for congestive heart failure and has a known history of HFpEF. He is tachycardic, his BP has become more labile, and the critical care fellow has performed a bedside TTE to try to determine the cause of his instability. The parasternal short-axis view obtained is shown in image Video 41.6. The fellow says this must be hypovolemia and wishes to give more fluid. From image Video 41.6, what might lead you toward administering vasopressors over additional fluids?

A. The high HR

B. Normal end-diastolic diameter

C. Small end-diastolic diameter

D. Myocardial hypertrophy

View Answer

5. Correct Answer: B. Normal end-diastolic diameter

Rationale: It cannot be emphasized enough that clinical decisions should rarely, if ever, be based on a single image. Still, image Video 41.6 can lead you to obtain other images that may or may not support your initial suspicion. This patient is tachycardic, hypotensive, and hyperdynamic. The initial thought is that the patient must be hypovolemic. However, one needs to look closer. Pause the video and scroll through it slowly. A low systemic vascular resistance (SVR) state, such as sepsis, can often present the same way. However, in this short-axis view, if the patient is euvolemic but with a low SVR state, the end-diastolic diameter will generally be normal. A hypovolemic heart will not fill and thus will have a decreased end-diastolic diameter. Of course, the patient could be both hypovolemic and have a low SVR state and thus more specific measures of volume status should be obtained.

Selected Reference

1. McLean AS. Echocardiography in shock management. Crit Care. 2016;20:275.

6. A 74-year-old male nursing home resident is intubated in the ICU with bilateral pneumonia and acute respiratory distress syndrome (ARDS). He is currently on 6 cc/kg tidal volume with 10 cm H2O positive end-expiratory pressure (PEEP). He is in septic shock and is on norepinephrine and vasopressin infusions. He has a history of hypertension and HFpEF. Lung ultrasound examination reveals B-lines, and his chest X-ray shows pulmonary edema. His creatinine has started to rise and his urine output has drifted off. By echocardiogram, a PLR results in a 16% increase in his left-ventricular outflow tract (LVOT) velocity-time integral (VTI) so you decide to give a fluid bolus. Your ICU fellow questions the wisdom of this given that the patient already has pulmonary edema and additional fluid may worsen his oxygenation. What ultrasound tool can be used to help determine if more fluid may contribute to worsening of his pulmonary edema?

A. Measure changes in the size of the pleural effusions using lung ultrasound

B. Look for loss of IVC respiratory variation

C. Use continuous-wave Doppler (CWD) of the pulmonic insufficiency (PI) jet to determine the pulmonary artery diastolic pressure (PADP)

D. Look at the mitral E/e’ as a measure of left atrial pressure

View Answer

6. Correct Answer: D. Look at the mitral E/e’ as a measure of left atrial pressure

Rationale: This patient is showing signs of end-organ dysfunction that may benefit from additional volume administration and you have echocardiographic evidence that the patient should be volume responsive. However, just because a patient is volume responsive does not mean the patient absolutely needs to receive volume. The very valid concern here is that additional fluid may worsen this patient’s pulmonary edema, and we know that ARDS lungs tend to do better when they are dry. The concern is that additional volume will create cardiogenic pulmonary edema via a rise in the left atrial pressure. E/e′ is an accepted measure to reflect the left atrial pressure. This involves measuring mitral inflow velocity with PWD and tissue Doppler at the mitral annulus. An E/e′ > 14 indicates an elevated left atrial pressure and additional fluid has a significant chance of worsening this patient’s oxygenation. In a patient on low tidal-volume ventilation on significant PEEP, the IVC respiratory variation will be very insensitive for intravascular volume. Use of CWD on a PI jet can be used to determine the PADP, but this is a cheap surrogate for the actual left atrial pressure (LAP), which is what we really want to know.

Selected Reference

1. Militaru C, Deliu R, Donoiu I, Alexandru DO, Military CC. Echocardiographic parameters in acute pulmonary edema. Curr Health Sci J. 2017;43(4):345-350.

7. An otherwise healthy 20-year-old male involved in a motor vehicle collision (MVC) is brought to the ICU after ORIF of an unstable pelvic fracture. Estimated blood loss was approximately 2500 cc, and he received two units packed red blood cells (PRBCs) in the OR. He is hemodynamically unstable, requiring a phenylephrine infusion. Neuromuscular blockade was not reversed in the OR and he is receiving 8 cc/kg ideal body weight (IBW) tidal volumes. You perform a bedside TTE, and the pulsed-wave Doppler tracing from the LVOT is shown in Figure 41.1.

Based on Figure 41.1, what should be your first therapeutic maneuver to treat this patient’s hypotension?

A. Change phenylephrine to norepinephrine

B. Start epinephrine

C. Place an IABP

D. 500 cc fluid bolus

View Answer

7. Correct Answer: D. 500 cc fluid bolus

Rationale: While we want to avoid making clinical decisions based on only one image, Figure 41.1 shows respiratory variation in VTI in the LVOT in this paralyzed patient taking large tidal volumes and is highly suggestive that he will be volume responsive. Greater than 12% change in the peak velocities with respiration is highly sensitive and specific for volume responsiveness.

Selected Reference

1. Feissel M, Michard F, Mangin I, Ruyer O, Faller JP, Teboul JL. Respiratory changes in aortic blood velocity as an indicator of fluid responsiveness in ventilated patients with septic shock. Chest. 2001;119(3):867-873.

8. An intubated obese 32-year-old female without other medical problems arrives from the OR intubated, in septic shock, on norepinephrine, after removal of an infected ureteral stone. You are unable to obtain good echo images on this woman.

She is heavily sedated on AC/VC ventilation with 8 cc/kg IBW tidal volumes. She does not have central venous access, and as you scan her right internal jugular vein (IJV) to place a line you note that there is significant respiratory variation in the diameter of her IJV (Figure 41.2). Which of the following parameters might suggest volume responsiveness?

A. IJV collapsibility >20%

B. IJV collapsibility >10%

C. IJV distensibility >18%

D. IJV distensibility >10%

View Answer

8. Correct Answer: C. IJV distensibility >18%

Rationale: In a passively mechanically ventilated patient, IJV distensibility >18% prior to volume challenge has about 80% sensitivity and 85% specificity for identification of volume responsiveness.

Selected Reference

1. Guarracino F, Ferro B, Forfori F, Bertini P, Magliacano L, Pinsky MR. Jugular vein distensibility predicts fluid responsiveness in septic patients. Crit Care. 2014;18:647.

9. A 62-year-old woman with a history of HFpEF is admitted to the ICU after an MVC from which she has suffered bilateral lung contusions. Lung ultrasound (Figure 41.3) shows bilateral B-lines throughout both anterior lung fields. She was aggressively volume resuscitated in the Emergency Department (ED), and you are concerned she may be developing heart failure. She is hemodynamically stable, and echo confirms she has normal biventricular systolic function.

You question if diuresis may be beneficial to improve oxygenation. Which of the listed echo parameters may best indicate that diuresis may be beneficial in this scenario using TTE?

A. Plethoric IVC on subcostal imaging

B. E/e′>14

C. Superior vena cava (SVC) collapsibility index

D. Pulsed-wave Doppler (PWD) respiratory variation in the LVOT

View Answer

9. Correct Answer: B. E/e′>14

Rationale: A plethoric IVC certainly helps suggest that the patient is not severely hypovolemic but does not really help us decide about volume overload. The same applies to SVC collapsibility, and it requires TEE to reliably obtain. Variation in the peak Doppler velocity in the LVOT may also help with the determination of volume responsiveness, but not necessarily if the patient may respond to diuresis. The E/e′ ratio is the ratio of the E-wave using PWD through the mitral valve to the tissue Doppler e′ wave on the mitral annulus. An E/e′ velocity ratio >14 is highly correlated with an elevation in left atrial pressure. A low E/e′ gives the intensivist more confidence that the pulmonary edema is noncardiogenic in origin.

Selected Reference

1. Militaru C, Deliu R, Donoiu I, Alexandru DO, Military CC. Echocardiographic parameters in acute pulmonary edema. Curr Health Sci J. 2017;43(4):345-350.

10. A 55-year-old male with COVID-19 and severe ARDS is intubated in the ICU. He is intubated on low tidal-volume ventilation with 15 cm H2O PEEP. He has just been returned supine after 18 hours in the prone positiona. He has an acute kidney injury and is hypotensive on norepinephrine. TTE has confirmed that his biventricular systolic function appears normal. You are questioning whether to give additional fluid but are concerned about how poor his oxygenation is. Which of the following is the best application of echocardiography to determine if this patient will respond to additional fluid?

A. VTI variation in the LVOT

B. IVC distensibility

C. Perform a PLR and look for changes in SV

D. Measure the end-diastolic area of the left ventricle (LVEDA)

View Answer

10. Correct Answer: C. Perform a PLR and look for changes in SV

Rationale: A PLR causes the autotransfusion of approximately 300 cc of blood into the right side of the heart (Figure 41.13). A significant change in SV of >12% or so is consistent with the patient being volume responsive. Performing the PLR avoids giving a potentially detrimental fluid bolus and allows the intensivist to predict in advance if the patient should respond to fluid. VTI variation in the LVOT and IVC distensibility are really only applicable in the setting of tidal volumes over 8 cc/kg IBW. This patient with ARDS requires low tidal-volume ventilation so these measures would not be valid. The EDA by echo has limited sensitivity to assessment of volume responsiveness by itself.

Selected Reference

1. Monnet X, Rienzo M, Osman D, et al. Passive leg raising predicts fluid responsiveness in the critically ill. Crit Care Med. 2006;34(5):1402-1407.

11. A 42-year-old male patient arrives intubated from the ED after being involved in an MVC. He has bilateral lung contusions and is on 90% FiO2 with bilateral chest tubes. He is currently being ventilated with 6 cc/kg IBW tidal volumes and is on 12 cm H2O PEEP. Lung ultrasound shows diffuse bilateral B-lines. Echo in the ED confirmed biventricular normal systolic function. He has a pelvic fracture that will require operative intervention. On arrival, his systolic BP is in the 80s (mm Hg) and the nurse asks
to start a norepinephrine drip. What is the best way to determine whether this patient will respond to intravascular volume using TTE?

A. PLR maneuver to assess changes in SV

B. Look at IVC distensibility

C. Look at changes in LVOT VTI from breath to breath

D. Measure changes in VTI after an end-expiratory occlusion pressure

View Answer

11. Correct Answer: D. Measure changes in VTI after an end-expiratory occlusion pressure

Rationale: While a PLR is a valuable tool to assess response to volume, this patient’s pelvic fractures would not make it a wise option to perform IVC distensibility. Changes in LVOT VTI have only been validated in the setting of large tidal volumes >8 cc/kg, which is not applicable to this patient with bilateral lung contusions. In this patient, an end-expiratory occlusion maneuver can be performed. An increase in CO >4% after an end-expiratory occlusion reliably predicts fluid responsiveness.

Selected Reference

1. Jozwiak M, Depret F, Teboul JL, et al. Predicting fluid responsiveness in critically ill patients by using combined end-expiratory and end-inspiratory occlusions with echocardiography. Crit Care Med. 2017;45:e1131-e1138.

12. Twenty minutes after a laparoscopic hemicolectomy, a 72-year-old patient is found to be hypotensive (65/35 mm Hg) in the PACU, is unresponsive to a 2 L fluid bolus, and has a distended abdomen. Past medical history includes hypertension, coronary artery disease (s/p CABG), and diabetes. A brief TTE shows an LV ejection fraction of 70%, no obvious regional wall motion abnormalities, and an end-diastolic area (EDA) of 8.5 cm2 in a parasternal short-axis view. The most appropriate next course of action is:

A. Emergent left heart catheterization

B. Return to OR for exploratory laparotomy

C. Broad-spectrum antibiotics and initiation of vasopressors

D. Additional 2 L fluid bolus

View Answer

12. Correct Answer: D. Additional 2 L fluid bolus

Rationale: Low EDA < 10 cm2 from a parasternal short-axis view is consistent with decreased preload, likely due to intra-abdominal hemorrhage in this patient. While fluid resuscitation should be initiated at that moment, a focused assessment with sonography in trauma (FAST) examination should also be performed to look for free fluid in the abdomen, suggestive of bleeding that might necessitate a return trip to the OR.

Selected Reference

1. Miller A, Mandeville J. Predicting and measuring fluid responsiveness with echocardiography. Echo Res Pract. 2016;3:G1-G12.

13. A 42-year-old male is intubated and sedated with acute pancreatitis. Despite aggressive fluid resuscitation, he remains hypotensive with low urine output. Which of the following findings are consistent with fluid responsiveness in a patient on positive pressure ventilation?

A. An ejection fraction of 70% with “kissing” papillary muscles

B. A change in PWD peak velocity through the LVOT of 14% between inhalation and exhalation

C. Consistent mitral inflow velocities throughout the respiratory cycle

D. An ejection fraction of 25% with a dilated left ventricle

View Answer

13. Correct Answer: B. A change in PWD peak velocity through the LVOT of 14% from systolic beat to beat

Rationale: Changes in PWD flow through the LVOT >12% have been shown to predict fluid responsiveness and an increase in cardiac index >15%. It is important to keep in mind that this is only valid in patients mechanically ventilated at a tidal volume >8 cc/kg IBW and without spontaneous breathing efforts.

Selected Reference

1. Feissel M, Michard F, Mangin I, Ruyer O, Faller JP, Teboul JL. Respiratory changes in aortic blood velocity as an indicator of fluid responsiveness in ventilated patients with septic shock. Chest. 2001;119:867-873.

14. A 23-year-old male presents to the trauma bay with multiple gunshot wounds to the abdomen and is taken immediately to the OR. Massive transfusion via a rapid transfusion device is initiated as the bleeding is controlled. Which of the following would be an indicator of over-transfusion when administering a 500 mL fluid bolus?

A. RV dilation without a change in BP

B. A decrease in peak mitral E-wave velocity variation during inspiration and expiration

C. Increased VTI in the LVOT

D. Increased lateral mitral annular systolic velocity (s′)

View Answer

14. Correct Answer: A. RV dilation without a change in BP

Rationale: RV dilation without increases in SV are an indicator of over-transfusion. Septal flattening indicated RV volume overload. Iatrogenic RV failure secondary to overaggressive rapid volume administration is an important consideration.

Selected References

1. Feneley M, Gavaghan T. Paradoxical and pseudoparadoxical interventricular septal motion in patients with right ventricular volume overload. Circulation. 1986;74:230-238.

2. Miller A, Mandeville J. Predicting and measuring fluid responsiveness with echocardiography. Echo Res Pract. 2016;3:G1-G12.

15. A 16-year-old male became unresponsive during football practice in July. He arrived at the ED without obvious trauma, hypotensive, with a temperature of 41 °C, a Glasgow Coma Scale (GCS) of 8. He is intubated and aggressive fluid resuscitation and active cooling have been initiated. Which of the following is an indicator of further need for fluid resuscitation?

A. SV calculated via LVOT VTI of 80 mL with a HR of 90 bpm

B. IVC diameter of 1.2 cm during expiration and 1.4 cm during inspiration

C. Hyperdynamic left ventricle with an ejection fraction of 70%

D. Peak LVOT velocity of 1.2 cm/s during expiration and 0.8 cm/s during inspiration

View Answer

15. Correct Answer: D. Peak LVOT peak velocity of 1.2 cm/s during expiration and 0.8 cm/s during inspiration

Rationale: Changes in LVOT peak velocities during inspiration and expiration >12% have been shown to be more sensitive and specific than changes in IVC diameter >8% in assessing for fluid responsiveness when tidal volumes of >8 cc/kg IBW are used transiently.

Selected Reference

1. Vignon P, Repesse X, Begot E, et al. Comparison of echocardiographic indices used to predict fluid responsiveness in ventilated patients. Am J Respir Crit Care Med. 2017;195:1022-1032.

16. Which one of the following parameters can be used to calculate mean pulmonary artery pressures in Figure 41.4?

A. Peak velocity of early transpulmonary flow

B. Speed of early tissue relaxation velocity

C. Pulmonary artery VTI acceleration time

D. CWD assessment of the tricuspid regurgitation jet

View Answer

16. Correct Answer: C. Pulmonary artery VTI acceleration time

Rationale: Right ventricular outflow tract (RVOT) acceleration time (RVAT) is measured from the beginning of the flow to the peak flow velocity. It is important that the marker is placed at the peak first and then tracked back to the onset of flow, as the aim is to measure time taken to peak velocity and not the propagation. A value of >130 ms is normal, while <100 ms is highly suggestive of pulmonary hypertension. Mean pulmonary pressure is calculated by the formula: mPAP = 90 – (0.62*ATRVOT). While not a direct measure of volume responsiveness, elevated mean pulmonary artery pressures may make the intensivist more wary of giving excessive fluids due to concern for RV volume overload.

Selected Reference

1. Parasuraman S, Walker S, Loudon BL, et al. Assessment of pulmonary artery pressure by echocardiography—a comprehensive review. Int J Cardiol Heart Vasc. 2016;12:45-51.

17. A 79-year-old male is booked for an ORIF of a femur fracture. His past medical history is significant for hypertension controlled on hydrochlorothiazide. As a newly trained anesthesiologist proficient in bedside ultrasound, you perform an echocardiogram after hearing a prominent systolic murmur. The parasternal long-axis view is shown in image Video 41.7. You plan a standard induction with propofol and use rocuronium as a neuromuscular blocker. Postintubation, the BP drops from 150/90 mm Hg to 90/50 and HR increases from 50 to 90 bpm. Which of the following agents would you use to manage his hypotension?

A. Ephedrine

B. Phenylephrine

C. One liter fluid bolus

D. Epinephrine

View Answer

17. Correct Answer: B. Phenylephrine

Rationale: In hypotensive patients with aortic stenosis (AS), phenylephrine is the drug of choice. LV afterload is relatively fixed due to the stenotic valve; increasing SVR will have minimal effect on myocardial work; also increasing the diastolic pressure will increase the coronary perfusion pressure and thus myocardial oxygen delivery. Phenylephrine will also decrease HR by its reflex bradycardia action, improve diastolic filling of the left ventricle, and thereby increase SV. Severe aortic stenosis is not a volume-depleted state unless there are other variables to also suggest hypovolemia.

Selected Reference

1. Samarendra P, Mangione MP. Aortic stenosis and perioperative risk with noncardiac surgery. J Am Coll Cardiol. 2015;65(3):295-302.

18. Which of the following dynamic parameters in image Video 41.8 would point toward a patient that is responsive to fluid?

A. SVC collapsibility > 36%

B. IVC collapsibility >36%

C. SVC collapsibility > 12%

D. IVC collapsibility > 12%

View Answer

18. Correct Answer: A. SVC collapsibility >36%

Rationale: SVC collapsibility >36% is very sensitive and specific for hypovolemia in patients on passive mechanical ventilation with >8 cc/kg IBW tidal volumes. TEE is required to image the SVC reliably. Mechanical ventilation will cause distension of the IVC, as it is not an intrathoracic structure. Collapsibility >50% is usually necessary in the spontaneously ventilating patient to suggest volume responsiveness.

Selected Reference

1. Vieillard-Baron A, Chergui K, Rabiller A, et al. Superior vena caval collapsibility as a gauge of volume status in ventilated septic patients. Intensive Care Med. 2004;30(9):1734-1739.

19. A morbidly obese 58-year-old male comes to the OR for a robotic prostatectomy. As a part of your physical examination you perform a surface echo and note plethora of the IVC. Doppler interrogation of the hepatic veins is shown in Figure 41.5.

Which of the following valvular conditions does this patient have?

A. Mitral regurgitation

B. Mitral stenosis

C. Tricuspid regurgitation

D. Tricuspid stenosis

View Answer

19. Correct Answer: C. Tricuspid regurgitation

Rationale: Significant tricuspid regurgitation can cause a plethoric IVC, making respiratory variation in the size of the IVC to gauge volume status very unreliable. PWD interrogation of the hepatic veins shows reversal of the S wave, consistent with severe tricuspid regurgitation.

Selected Reference

1. Zoghbi WA, Adams D, Bonow RO, et al. Recommendations for noninvasive evaluation of native valvular regurgitation: a report from the American Society of Echocardiography Developed in Collaboration with the Society for Cardiovascular Magnetic Resonance. J Am Soc Echocardiogr. 2017;30(4):303-371.

20. Which of the following views will be optimal to assess the LVOT velocities?

A. Apical five chamber

B. Apical four chamber

C. Subcostal five chamber

D. Subcostal four chamber

View Answer

20. Correct Answer: A. Apical five chamber

Rationale: The apical five-chamber view allows the PWD beam to align in the direction of flow in the LVOT. Determination of the VTI, in combination with the calculated LVOT area, allows one to calculate the SV. Changes in SV can be used to guide fluid resuscitation.

Selected Reference

1. Mercado P, Maizel J, Beyls C, et al. Transthoracic echocardiography: an accurate and precise method for estimating cardiac output in the critically ill patient. Crit Care. 2017;21:136.

21. Which of the following conditions can lead to what is shown in image Video 41.9?

A. RV volume overload

B. LV failure

C. Aortic stenosis

D. Cardiac tamponade

View Answer

21. Correct Answer: A. RV volume overload

Rationale/Critique: This parasternal short-axis TTE (image Video 41.9) shows flattening of the interventricular septum during diastole, consistent with high RV volume overload, and implies that additional fluid resuscitation is not going to be helpful. Flattening of septum during RV systole implies RV pressure overload.

Selected Reference

1. Alaverdian A, Cohen RI. The right ventricle in critical illness. Open Crit Care Med J. 2010;3:38-42.

22. What is the most likely cause of hypotension followed by cardiac arrest on administration of propofol to this patient for intubation (see image Video 41.10)?

A. Aortic stenosis

B. LV failure

C. Dynamic LVOT obstruction

D. Aortic dissection

View Answer

22. Correct Answer: C. Dynamic LVOT obstruction

Rationale: This patient likely has hypertrophic cardiomyopathy based on the hypertrophic left ventricle seen in image Video 41.10. Acute decreases in LV afterload or hypovolemia may lead to SAM of the mitral valve, causing dynamic LVOT obstruction and hemodynamic collapse. Aggressive volume administration is the mainstay of treatment, along with beta-blockade and increasing SVR.

Selected Reference

1. Oxlund CS, Poulsen MK, Jensen PB, Veien KT, Møller JE. A case report: hemodynamic instability due to true dynamic LVOT obstruction and systolic anterior motion following resuscitation: reversal of haemodynamics on supportive veno-arterial extracorporeal membrane oxygenation. Eur Heart J Case Rep. 2018;2(4):yty134.

23. Estimate the CVP from IVC in Figure 41.6 and image Video 41.11.

A. >10

B. 5-10

C. <5

D. Cannot be estimated

View Answer

23. Correct Answer: C. <5

Rationale: An IVC demonstrating >50% collapse with respiration with a diameter <2.1 cm is consistent with a very low CVP <5 mm Hg

Selected Reference

1. Ilyas A, Ishtiaq W, Assad S, et al. Correlation of IVC diameter and collapsibility index with central venous pressure in the assessment of intravascular volume in critically ill patients. Cureus. 2017;9(2):e1025.Published online 2017 Feb 12.

24. A 24-year-old male presents to the ICU after a MVC. He complains of abdominal pain and chest pain with a positive seat-belt sign. Shortly after his arrival, he becomes profoundly hypotensive. A PLR maneuver is performed as a TTE examination is being performed. Which of the following findings during PLR is most consistent with fluid responsiveness?

A. RV dilation and reduced tricuspid annular plane systolic excursion (TAPSE)

B. Increased stroke distance through the LVOT using PWD by 20%

C. Anterior wall hypokinesis

D. A circumferential 2 cm pericardial effusion

Jun 9, 2022 | Posted by in CARDIOLOGY | Comments Off on Hypovolemic Shock
Premium Wordpress Themes by UFO Themes