Journal of Clinical Anesthesia (2014) xx, xxx–xxx
Case Report
Quadriparesis from air emboli during percutaneous nephrolithotomy Dustin L. Hegland MD (Clinical Assistant Professor of Anesthesiology)a,b,⁎, Benjamin K. Canales MD (Assistant Professor of Urology)c , Robert I. Katz MD (Professor of Anesthesiology)a,b a
Anesthesiology Service, Malcom Randall VA Medical Center, Gainesville, FL 32608, USA Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL 32610, USA c Department of Urology, University of Florida College of Medicine, Gainesville, FL 32610, USA b
Received 1 June 2012; revised 31 December 2013; accepted 10 January 2014
Keywords: Air embolism; Percutaneous nephrolithotomy; Quadriparesis
Abstract Quadriparesis is a potentially catastrophic complication during operative procedures. It may result from a number of different types of central nervous system insults. A case of quadriparesis following an otherwise unremarkable percutaneous nephrolithotomy surgery is reported. The quadriparesis resulted from multiple air micro emboli. Published by Elsevier Inc.
1. Introduction
2. Case Report
Air embolism during percutaneous nephrolithotomy is a rare complication [1]. This complication can occur when an air pyelogram is performed to differentiate the posterior from the anterior calyces of the kidney. The injected air has the potential to travel through the vasculature producing both occlusive and inflammatory changes. This patient underwent an otherwise unremarkable prone position renal calculus removal. On arrival at the Postanesthesia Care Unit (PACU), the patient was unable to move his upper or lower extremities. He also experienced a brief period of altered mental status accompanied by right beating nystagmus eye movement. Extensive evaluation, including magnetic resonance imaging (MRI), identified multifocal synchronous bilateral cerebral infarcts suggestive of air emboli.
A 62 year old man with a past medical history of wellcontrolled hypertension and obesity, was scheduled for a prone position right percutaneous nephrolithotomy for removal of a 2.5 centimeter renal calculus. The patient was monitored throughout the procedure using electrocardiography (ECG), pulse oximetry, noninvasive blood pressure cuff, and end-tidal carbon dioxide (ETCO2). Induction of anesthesia and positioning of the patient were unremarkable. At the time of pneumopyelography, as air was injected into the kidney to visualize the structures of the renal pelvis, the patient experienced a decrease in ETCO2 to 20 mmHg and mild hypotension with a systolic blood pressure (SBP) of 90 mmHg. These features resolved over approximately 10 minutes after fluid administration, along with divided-dose administration of phenylephrine. The patient was otherwise normotensive throughout the course of anesthesia. The remainder of the procedure was completed without incident. At the conclusion of the procedure, the patient was repositioned supine, muscle relaxation was reversed with
⁎ Correspondence: Dustin L. Hegland, MD, Malcom Randall VA Medical Center, Department of Anesthesiology, 1601 S.W. Archer Rd., Gainesville, FL 32608, USA. Tel.: 352 367–1611; Fax: 352 374-6154. E-mail address: [email protected] (D.L. Hegland). http://dx.doi.org/10.1016/j.jclinane.2014.01.007 0952-8180/Published by Elsevier Inc.
2 confirmation of a four out of four twitch response with sustained tetanus using a neuromuscular twitch monitor, and observation of appropriate minute ventilation. Respiration was considered to be adequate despite continued somnolence. The trachea was then extubated and the patient was taken to the PACU. Approximately 20 minutes after his arrival at the PACU, the patient’s mentation had become more lucid and he noted profound weakness in his upper and lower extremities. On examination, the patient offered only minimal volitional extremity movement and displayed no withdrawal or appreciable sensation to pain stimulus. During this examination, he exhibited a period of incoherence accompanied by right beating eye nystagmus that was concerning for a possible seizure event. Neurology was immediately consulted. Postoperative laboratory testing showed no electrolyte abnormalities or other notable findings. Preoperative and postoperative glucose levels were within normal limits. A computed tomographic (CT) angiogram was unremarkable. The patient subsequently underwent T1 and T2 MRI of the cervical spine and cranial vault (Fig. 1). The radiologist reported, “Multi-
D.L. Hegland et al. focal synchronous early subacute infarcts in the cerebral hemispheres bilaterally. The distribution and the lack of arterial disease in the head and neck, and the peripheral nature suggest small emboli, possibly air embolus. Hypoglycemia can have a similar appearance and this should be correlated with the clinical history. There is no involvement of the deep gray matter (high ATP zones) to suggest acute hypoxic injury, and the pathologic findings are more consistent with embolic disease versus questionable hypoglycemia. These lesions are not limited to watershed zones.” MR angiography reconfirmed the CT angiography findings of normal vasculature without evidence of dissections, aneurysms, stenoses, or excessive atherosclerotic disease. Similarly, the cervical spine evaluation showed no evidence of contusion, inflammation, or any other abnormalities. The patient’s condition was considered to be highly concerning but stable, and he was accordingly moved from the PACU to a monitored intensive care unit setting where his evaluation continued. A 12-channel electroencephalogram (EEG) was unremarkable. With concern for the MRI description of possible air emboli-induced infarctions, a transthoracic echocardiogram with agitated saline contrast, a
Fig. 1 (A) Non-contrast T2-weighted magnetic resonance diffusion-weighted imaging (DWI) and (C) fluid-attenuated inversion recovery (FLAIR) images showed increased signal intensity in multiple vascular territories. Apparent diffusion coefficient (ADC) image (B) remained dark, consistent with restricted diffusion and infarct. Similar wedge-shaped areas of restricted diffusion were seen in DWI image (D) and ADC image (E) in the left anterior frontal cortex. FLAIR image (F) showed corresponding increased signal in the left anterior frontal lobe consistent with edema from acute to subacute infarct. Additional areas of increased signal in the subcortical white matter lack restricted diffusion and were consistent with chronic demyelination, likely due to chronic small-vessel ischemia.
Quadriparesis in nephrolithotomy “bubble study,” was performed; it did not identify an obvious patent foramen ovale or other intracardiac shunt. The patient’s extremity weakness slowly improved during the course of his two week hospital stay and evaluation, but unfortunately never returned to baseline. After hospital discharge, he subsequently underwent several weeks of physical therapy and rehabilitation at a poststroke-assisted living facility. Four months after the event, he described mild subjective lower-extremity weakness and his functional status is slowly improving.
3. Discussion The variety of central nervous system insults that may produce quadriparesis is relatively limited, including cerebrovascular injury and electrolyte and glucose abnormalities. The patient’s symptom combination of quadriparesis with possible seizure pointed to the need for immediate evaluation for brainstem ischemia from either embolism or dissection. The patient’s normal CT angiogram ruled out this etiology. Other possible causes requiring evaluation included cervical spine positioning injury from the prone position or, alternatively, other cerebral vascular events. Both of these were best assessed with MRI of the cervical spine and cranial vault. The cervical spine MRI demonstrated no notable abnormalities. However, the combination of intraoperative decrease in ETCO2 with mild hypotension during pneumopyelography, plus the MRI findings of the cranial vault described in the case description suggest air emboli as the cause of the neurologic insult. The lack of watershed distribution makes simple hypotension an unlikely explanation. The distribution, location, and synchronous nature of the infarction lesions speak to the obstruction to microvascular flow and inflammation that would be expected with air microemboli. The apparent seizure in the PACU is attributed to the microinfarctions and continued dispersal of air over time. The possibility that the quadraparesis was due to spinal cord compression from the patient’s position was ruled out by the cervical spine MRI’s failure to demonstrate contusion, edema, or any other abnormality. Regarding evaluation of the vascular path taken by the air emboli to reach the cerebral circulation, the patient had a negative contrast echocardiography examination. There are a number of plausible explanations for this negative examination, or at least for its nonessential relevance [2]. Contrast echocardiography has a sensitivity to detect intracardiac
3 shunts greater than 80% of the time, but the test is still imperfect [3]. This may be due to technical error in the administration of the agitated saline contrast, inappropriate equipment settings, or inadequate patient execution of the required Valsalva maneuver. Other physiology studies and case reports have also suggested the possibility of air emboli travel through the pulmonary capillary bed or prepulmonary arterial venous shunts [4]. Publication of a review paper considering neurologic complications in 30,666 percutaneous nephrolithotomy procedures [5], identified 11 patients who experienced neurologic injury, including 4 instances of paraplegia. All of the 11 cases occurred during prone positioning and the use of air for renal calyx visualizaion. Neither the use of air nor prone positioning is essential to the performance of percutaneous nephrolithotomy procedures. Radiographic visualization of the renal calyx using injected carbon dioxide is comparable to what is achieved with room air. An advantage to the use of carbon dioxide is its highly soluble nature leading to rapid dissolving of the injected gas into blood and minimization of the risk of neurologic embolic events. Prone positioning provides obvious access for the proceduralist’s approach to the kidney. However, alternatives have been described [6] and are used at some institutions as a means of avoiding the inconvenience and potential complications of the prone position. The rarity of the event would make it difficult to demonstrate definitively that use of supine position variations, such as the Valdivia or Galakao modified Valdivia position [6], reduces the risk of neurologic injury from gas embolism.
References [1] Miller RA, Kellet MJ, Wickham JE. Air embolism, a new complication of percutaneous nephrolithotomy. What are the implications? J Urol 1984;90:337-9. [2] Tommasino C, Rizzardi R, Beretta L, Venturino M, Piccoli S. Cerebral ischemia after venous air embolism in the absence of intracardiac defects. J Neurosurg Anesthesiol 1996;8:30-4. [3] Seiler C. How should we assess patent foramen ovale? Heart 2004;90: 1245-7. [4] Kachalia AG, Savant CS, Patil S, Gupta S, Kapadia FN. Cerebral and spinal air embolism following percutaneous nephrolithotomy. J Assoc Physicians India 2011;59:254-6. [5] Basiri A, Soltani MH, Kamranmanesh M, et al. Neurologic complications in percutaneous nephrolithotomy. Korean J Urol 2013;54:172-6. [6] Miano R, Scoffone C, De Nunzio C, et al; International Translation Research in Uro-Sciences Team. Position: prone or supine is the issue of percutaneous nephrolithotomy. J Endourol 2010;24:931-8.
Case Report
Quadriparesis from air emboli during percutaneous nephrolithotomy Dustin L. Hegland MD (Clinical Assistant Professor of Anesthesiology)a,b,⁎, Benjamin K. Canales MD (Assistant Professor of Urology)c , Robert I. Katz MD (Professor of Anesthesiology)a,b a
Anesthesiology Service, Malcom Randall VA Medical Center, Gainesville, FL 32608, USA Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL 32610, USA c Department of Urology, University of Florida College of Medicine, Gainesville, FL 32610, USA b
Received 1 June 2012; revised 31 December 2013; accepted 10 January 2014
Keywords: Air embolism; Percutaneous nephrolithotomy; Quadriparesis
Abstract Quadriparesis is a potentially catastrophic complication during operative procedures. It may result from a number of different types of central nervous system insults. A case of quadriparesis following an otherwise unremarkable percutaneous nephrolithotomy surgery is reported. The quadriparesis resulted from multiple air micro emboli. Published by Elsevier Inc.
1. Introduction
2. Case Report
Air embolism during percutaneous nephrolithotomy is a rare complication [1]. This complication can occur when an air pyelogram is performed to differentiate the posterior from the anterior calyces of the kidney. The injected air has the potential to travel through the vasculature producing both occlusive and inflammatory changes. This patient underwent an otherwise unremarkable prone position renal calculus removal. On arrival at the Postanesthesia Care Unit (PACU), the patient was unable to move his upper or lower extremities. He also experienced a brief period of altered mental status accompanied by right beating nystagmus eye movement. Extensive evaluation, including magnetic resonance imaging (MRI), identified multifocal synchronous bilateral cerebral infarcts suggestive of air emboli.
A 62 year old man with a past medical history of wellcontrolled hypertension and obesity, was scheduled for a prone position right percutaneous nephrolithotomy for removal of a 2.5 centimeter renal calculus. The patient was monitored throughout the procedure using electrocardiography (ECG), pulse oximetry, noninvasive blood pressure cuff, and end-tidal carbon dioxide (ETCO2). Induction of anesthesia and positioning of the patient were unremarkable. At the time of pneumopyelography, as air was injected into the kidney to visualize the structures of the renal pelvis, the patient experienced a decrease in ETCO2 to 20 mmHg and mild hypotension with a systolic blood pressure (SBP) of 90 mmHg. These features resolved over approximately 10 minutes after fluid administration, along with divided-dose administration of phenylephrine. The patient was otherwise normotensive throughout the course of anesthesia. The remainder of the procedure was completed without incident. At the conclusion of the procedure, the patient was repositioned supine, muscle relaxation was reversed with
⁎ Correspondence: Dustin L. Hegland, MD, Malcom Randall VA Medical Center, Department of Anesthesiology, 1601 S.W. Archer Rd., Gainesville, FL 32608, USA. Tel.: 352 367–1611; Fax: 352 374-6154. E-mail address: [email protected] (D.L. Hegland). http://dx.doi.org/10.1016/j.jclinane.2014.01.007 0952-8180/Published by Elsevier Inc.
2 confirmation of a four out of four twitch response with sustained tetanus using a neuromuscular twitch monitor, and observation of appropriate minute ventilation. Respiration was considered to be adequate despite continued somnolence. The trachea was then extubated and the patient was taken to the PACU. Approximately 20 minutes after his arrival at the PACU, the patient’s mentation had become more lucid and he noted profound weakness in his upper and lower extremities. On examination, the patient offered only minimal volitional extremity movement and displayed no withdrawal or appreciable sensation to pain stimulus. During this examination, he exhibited a period of incoherence accompanied by right beating eye nystagmus that was concerning for a possible seizure event. Neurology was immediately consulted. Postoperative laboratory testing showed no electrolyte abnormalities or other notable findings. Preoperative and postoperative glucose levels were within normal limits. A computed tomographic (CT) angiogram was unremarkable. The patient subsequently underwent T1 and T2 MRI of the cervical spine and cranial vault (Fig. 1). The radiologist reported, “Multi-
D.L. Hegland et al. focal synchronous early subacute infarcts in the cerebral hemispheres bilaterally. The distribution and the lack of arterial disease in the head and neck, and the peripheral nature suggest small emboli, possibly air embolus. Hypoglycemia can have a similar appearance and this should be correlated with the clinical history. There is no involvement of the deep gray matter (high ATP zones) to suggest acute hypoxic injury, and the pathologic findings are more consistent with embolic disease versus questionable hypoglycemia. These lesions are not limited to watershed zones.” MR angiography reconfirmed the CT angiography findings of normal vasculature without evidence of dissections, aneurysms, stenoses, or excessive atherosclerotic disease. Similarly, the cervical spine evaluation showed no evidence of contusion, inflammation, or any other abnormalities. The patient’s condition was considered to be highly concerning but stable, and he was accordingly moved from the PACU to a monitored intensive care unit setting where his evaluation continued. A 12-channel electroencephalogram (EEG) was unremarkable. With concern for the MRI description of possible air emboli-induced infarctions, a transthoracic echocardiogram with agitated saline contrast, a
Fig. 1 (A) Non-contrast T2-weighted magnetic resonance diffusion-weighted imaging (DWI) and (C) fluid-attenuated inversion recovery (FLAIR) images showed increased signal intensity in multiple vascular territories. Apparent diffusion coefficient (ADC) image (B) remained dark, consistent with restricted diffusion and infarct. Similar wedge-shaped areas of restricted diffusion were seen in DWI image (D) and ADC image (E) in the left anterior frontal cortex. FLAIR image (F) showed corresponding increased signal in the left anterior frontal lobe consistent with edema from acute to subacute infarct. Additional areas of increased signal in the subcortical white matter lack restricted diffusion and were consistent with chronic demyelination, likely due to chronic small-vessel ischemia.
Quadriparesis in nephrolithotomy “bubble study,” was performed; it did not identify an obvious patent foramen ovale or other intracardiac shunt. The patient’s extremity weakness slowly improved during the course of his two week hospital stay and evaluation, but unfortunately never returned to baseline. After hospital discharge, he subsequently underwent several weeks of physical therapy and rehabilitation at a poststroke-assisted living facility. Four months after the event, he described mild subjective lower-extremity weakness and his functional status is slowly improving.
3. Discussion The variety of central nervous system insults that may produce quadriparesis is relatively limited, including cerebrovascular injury and electrolyte and glucose abnormalities. The patient’s symptom combination of quadriparesis with possible seizure pointed to the need for immediate evaluation for brainstem ischemia from either embolism or dissection. The patient’s normal CT angiogram ruled out this etiology. Other possible causes requiring evaluation included cervical spine positioning injury from the prone position or, alternatively, other cerebral vascular events. Both of these were best assessed with MRI of the cervical spine and cranial vault. The cervical spine MRI demonstrated no notable abnormalities. However, the combination of intraoperative decrease in ETCO2 with mild hypotension during pneumopyelography, plus the MRI findings of the cranial vault described in the case description suggest air emboli as the cause of the neurologic insult. The lack of watershed distribution makes simple hypotension an unlikely explanation. The distribution, location, and synchronous nature of the infarction lesions speak to the obstruction to microvascular flow and inflammation that would be expected with air microemboli. The apparent seizure in the PACU is attributed to the microinfarctions and continued dispersal of air over time. The possibility that the quadraparesis was due to spinal cord compression from the patient’s position was ruled out by the cervical spine MRI’s failure to demonstrate contusion, edema, or any other abnormality. Regarding evaluation of the vascular path taken by the air emboli to reach the cerebral circulation, the patient had a negative contrast echocardiography examination. There are a number of plausible explanations for this negative examination, or at least for its nonessential relevance [2]. Contrast echocardiography has a sensitivity to detect intracardiac
3 shunts greater than 80% of the time, but the test is still imperfect [3]. This may be due to technical error in the administration of the agitated saline contrast, inappropriate equipment settings, or inadequate patient execution of the required Valsalva maneuver. Other physiology studies and case reports have also suggested the possibility of air emboli travel through the pulmonary capillary bed or prepulmonary arterial venous shunts [4]. Publication of a review paper considering neurologic complications in 30,666 percutaneous nephrolithotomy procedures [5], identified 11 patients who experienced neurologic injury, including 4 instances of paraplegia. All of the 11 cases occurred during prone positioning and the use of air for renal calyx visualizaion. Neither the use of air nor prone positioning is essential to the performance of percutaneous nephrolithotomy procedures. Radiographic visualization of the renal calyx using injected carbon dioxide is comparable to what is achieved with room air. An advantage to the use of carbon dioxide is its highly soluble nature leading to rapid dissolving of the injected gas into blood and minimization of the risk of neurologic embolic events. Prone positioning provides obvious access for the proceduralist’s approach to the kidney. However, alternatives have been described [6] and are used at some institutions as a means of avoiding the inconvenience and potential complications of the prone position. The rarity of the event would make it difficult to demonstrate definitively that use of supine position variations, such as the Valdivia or Galakao modified Valdivia position [6], reduces the risk of neurologic injury from gas embolism.
References [1] Miller RA, Kellet MJ, Wickham JE. Air embolism, a new complication of percutaneous nephrolithotomy. What are the implications? J Urol 1984;90:337-9. [2] Tommasino C, Rizzardi R, Beretta L, Venturino M, Piccoli S. Cerebral ischemia after venous air embolism in the absence of intracardiac defects. J Neurosurg Anesthesiol 1996;8:30-4. [3] Seiler C. How should we assess patent foramen ovale? Heart 2004;90: 1245-7. [4] Kachalia AG, Savant CS, Patil S, Gupta S, Kapadia FN. Cerebral and spinal air embolism following percutaneous nephrolithotomy. J Assoc Physicians India 2011;59:254-6. [5] Basiri A, Soltani MH, Kamranmanesh M, et al. Neurologic complications in percutaneous nephrolithotomy. Korean J Urol 2013;54:172-6. [6] Miano R, Scoffone C, De Nunzio C, et al; International Translation Research in Uro-Sciences Team. Position: prone or supine is the issue of percutaneous nephrolithotomy. J Endourol 2010;24:931-8.
