Therapeutic hypothermia for acute myocardial infarction: a narrative review of evidence from animal and clinical studies / 대한마취과학회지

Myocardial infarction (MI) is the leading cause of death from coronary heart disease and requires immediate reperfusion therapy with thrombolysis, primary percutaneous coronary intervention, or coronary artery bypass grafting. However, myocardial reperfusion therapy is often accompanied by cardiac ischemia/reperfusion (I/R) injury, which leads to myocardial injury with detrimental consequences. The causes of I/R injury are unclear, but are multifactorial, including free radicals, reactive oxygen species, calcium overload, mitochondria dysfunction, inflammation, and neutrophil-mediated vascular injury. Mild hypothermia has been introduced as one of the potential inhibitors of myocardial I/R injury. Although animal studies have demonstrated that mild hypothermia significantly reduces or delays I/R myocardium damage, human trials have not shown clinical benefits in acute MI (AMI). In addition, the practice of hypothermia treatment is increasing in various fields such as surgical anesthesia and intensive care units. Adequate sedation for anesthetic procedures and protection from body shivering has become essential during therapeutic hypothermia. Therefore, anesthesiologists should be aware of the effects of therapeutic hypothermia on the metabolism of anesthetic drugs. In this paper, we review the existing data on the use of therapeutic hypothermia for AMI in animal models and human clinical trials to better understand the discrepancy between perceived benefits in preclinical animal models and the absence thereof in clinical trials thus far.

Severe postoperative dyspnea caused by neglected massive intraperitoneal fluid collection during laser enucleation and morcellation of the prostate: a case report / 대한마취과학회지

Laser enucleation and morcellation of the prostate is an increasingly used surgical management of benign prostatic hyperplasia. However, it can cause several complications including capsular perforation, ureteral orifice injury, and bladder mucosal morcellation injury. Herein, we report a case of severe postoperative dyspnea caused by neglected massive intraperitoneal fluid collection during laser surgery of the prostate. The patient experienced massive abdominal distension and severe respiratory difficulty after the procedure. Although immediate postoperative cystogram showed no leakage of contrast dye, the computed tomography scan of the abdomen and pelvis showed massive fluid collection in the abdominal pelvic cavity suggesting bladder wall injury. After percutaneous drainage of intraperitoneal fluid, abdominal distention and dyspnea were relieved.

Effect of electrically heated humidifier on intraoperative core body temperature decrease in elderly patients: a prospective observational study

BACKGROUND: Core body temperature (TC) can decrease during general anesthesia. Particularly in elderly patients, more aggressive strategies to prevent intraoperative hypothermia may be required. Here, we investigated the effect of a heated humidifier on intraoperative TC decrease in the elderly. METHODS: Twenty-four elderly patients were randomly assigned into two groups: those who used a heated humidifier (group H) and those who used a conventional ventilator circuit with a heat moisture exchanger (group C). TC was measured continuously at the esophagus at several time-points during surgery. RESULTS: In group C, TC significantly decreased 90 minutes after skin incision (P < 0.001), while significant differences were not noted in group H during surgery. Comparing the two groups, TC decreased more in group C than in group H at 60, 90, 120, and 150 minutes after skin incision (group C vs. group H: -0.6℃ vs. -0.3℃, P = 0.025; -0.7℃ vs. -0.4℃, P = 0.012; -0.9℃ vs. -0.4℃, P = 0.006; and -1.0℃ vs. -0.5℃, P = 0.013, respectively). There were no significant differences between the two groups for any other parameters. CONCLUSIONS: A heated humidifier is more effective in preventing intraoperative TC decrease in elderly patients than a heat moisture exchanger. However, further studies with a larger population are required to substantiate its clinical use.

Cerebral air embolism and subsequent transient neurologic abnormalities in a liver transplant recipient following the removal of the pulmonary artery catheter from the central venous access device: a case report / 대한마취과학회지

Cerebral air embolism is a rare but potentially life-threatening complication. We experienced a living-donor liver transplant recipient who presented with unexpected cerebral air embolism and transient neurologic abnormalities that subsequently developed just after the removal of the pulmonary artery catheter from the central venous access device. One day after the initial event, the patient's neurologic status gradually improved. The patient was discharged 30 days after liver transplantation without neurologic sequelae.

Vagolytic atropine attenuates cerebral vasodilation response during acute orthostatic hypotension / 대한마취과학회지

BACKGROUND: Atropine is an anticholinergic drug which is commonly used in clinical practice. The effect of parasympathetic block with atropine on dynamic cerebrovascular regulation remains unclear. This study was aimed to identify effects of vagolytic atropine on cerebrovascular response during acute orthostatic hypotension in humans. METHODS: Continuous middle cerebral blood flow velocity (CBFV, transcranial Doppler) and arterial blood pressure (ABP, Finometer) were measured during a sit-to-stand procedure in 10 healthy subjects with placebo and vagolytic (10 microg/kg) doses of atropine. Cerebral vascular tone was assessed by cerebrovascular resistance (CVR = ABP / CBFV). Dynamic cerebral autoregulation was also assessed by transfer function analysis of ABP and CBFV. RESULTS: During the standing session, ABP fell to a similar extent in both groups by an average of 23 to 25 mmHg (26% to 29%). CBFV also fell in all subjects but significantly more in vagolytic atropine (-15.0 +/- 7.0 cm/s) compared with placebo (-12.0 +/- 5.8 cm/s, P < 0.05). CVR was decreased significantly in the placebo group during posture change (1.56 +/- 0.44 vs. 1.38 +/- 0.38, P < 0.05), in contrast, lesser decreased in the atropine group (1.60 +/- 0.50 vs. 1.53 +/- 0.42, P = 0.193). Transfer function coherence in the very-low-frequency range was significantly increased in the atropine group during the standing session (0.55 +/- 0.14), compared with the sitting session (0.45 +/- 0.14, P = 0.006). CONCLUSIONS: These data present that vagolytic atropine attenuates cerebral vasodilation response to acute orthostatic hypotension, suggesting the use of atropine may need care in patients with cerebrovascular disease with vagal impairment.

Noninvasive estimation of raised intracranial pressure using ocular ultrasonography in liver transplant recipients with acute liver failure: A report of two cases / 대한마취과학회지

Intracranial pressure (ICP) monitoring is an important issue for liver transplant recipients, since increased ICP is associated with advanced hepatic encephalopathy or graft reperfusion during liver transplantation. Invasive monitoring of ICP is known as a gold standard method, but it can provoke bleeding and infection; thus, its use is a controversial issue. Studies have shown that optic nerve sheath diameter > 5 mm by ocular ultrasonography is useful for evaluating ICP > 20 mmHg noninvasively in many clinical settings. In this case report, we present experiences of using ocular ultrasound as a diagnostic tool that could detect changes in ICP noninvasively during liver transplantation.

Severe hemodynamic instability in a patient with suspected hepatoadrenal syndrome during liver transplantation: A case report / 대한마취과학회지

Adrenal insufficiency, which is related to hemodynamic instability and increased mortality, has been reported in patients with advanced liver disease regardless of the presence of septic conditions. In this regard, the hepatoadrenal syndrome has been recently proposed as adrenal insufficiency in critically ill patients with liver disease. We describe here a 67-year-old female patient with hepatic failure and adrenal insufficiency. The patient showed stable vital signs and no evidence of sepsis preoperatively. Despite hydrocortisone replacement and inotropics administration, severe intraoperative hemodynamic instability was observed. Hydrocortisone administration was continued postoperatively, nevertheless inotropics could not be tapered. On postoperative day 11, the patient died due to pneumonia and septic shock. Hepatoadrenal syndrome may have played a key role in her severe hemodynamic fluctuation and poor outcome, reinforcing the importance of adrenal function in the liver transplantation surgery.

Melatonin does not attenuate dynamic cardiovascular and cerebrovascular reflex responses to acute hypotension in healthy men / 대한마취과학회지

BACKGROUND: Melatonin has been shown to attenuate the reflex sympathetic increases that arise in response to orthostatic challenges. We tested the hypothesis that the attenuated sympathetic increase induced by melatonin premedication may weaken the arterial blood pressure (ABP) preserving the capability during acute hypotension, thereby altering dynamic cerebral autoregulation and causing a further decrease in cerebral blood flow (CBF). METHODS: Acute hypotension was induced in 12 healthy subjects by releasing bilateral thigh cuffs before and after an oral dose of melatonin (0.2 mg/kg). Heart rate (HR), arterial blood pressure (ABP), Modelflow estimate of cardiac output (CO), total peripheral resistance (TPR) and cerebral blood flow velocity (CBFV) by transcranial Doppler were measured. RESULTS: Steady state HR, the mean arterial pressure and CBFV were not altered 60 minutes after melatonin ingestion. Reduced systolic arterial pressure (DeltaSAP), changes in HR (DeltaHR), CO (DeltaCO), and TPR (DeltaTPR), DeltaHR/DeltaSAP and percentage restoration of SAP were not affected after a temporal decrease in ABP induced by thigh cuff release. In the cerebral circulation, melatonin did not affect changes in CBFV, cerebrovascular resistance index, the rate of regulation and percentage restoration of CBFV following a sudden decrease in ABP. CONCLUSIONS: Contrary to our hypothesis, melatonin did not affect the rapid vasodilatory and recovery responses of cardiovascular and dynamic cerebral autoregulation. These results suggest that melatonin premedication may not impair ABP and CBF preserving capability induced by sudden postural changes or hemorrhage.

Spectral analysis of respiratory-related hemodynamic variables in simulated hypovolemia: a study in healthy volunteers with spontaneous breathing using a paced breathing activity / 대한마취과학회지

BACKGROUND: A dynamic preload index such as stroke volume variation (SVV) is not as reliable in spontaneous breathing (SB) patients as in mechanically ventilated patients. This study examined the hypothesis that spectral analysis of hemodynamic variables during paced breathing (PB) activity may be a feasible index of volume changes and fluid responsiveness, despite insufficient respiratory changes in the preload index during SB activity. METHODS: Blood pressure and stroke volume (SV) were measured in 16 subjects undergoing PB (15 breaths/min), using a Finometer device and the Modelflow method. Respiratory systolic pressure variation (SPV) and SVV were measured and respiratory frequency (RF, 0.2-0.3 Hz) of power spectra of SPV (SPV(RF)) and SVV (SVV(RF)) were computed using fast Fourier transformation. Progressive hypovolemia was simulated with lower body negative pressure (LBNP). Volume challenges were produced by infusion of normal saline and subsequent release of LBNP to baseline. Fluid responsiveness, defined as a >20% increase in SV, was assessed by the area under the curve (AUC) of receiver operating characteristic curves. RESULTS: Graded hypovolemia caused a significant increase in SPV(RF) and a decrease in SVV(RF). During volume expansion, SPV(RF) decreased and SVV(RF) rose significantly. Fluid responsiveness was better predicted with SVV(RF) (AUC 0.75) than with SPV(RF), SPV, or SVV. SVV(RF) before volume challenge was significantly correlated with volume expansion-induced changes in SV (r = -0.64). CONCLUSIONS: These results suggest that RF spectral analysis of dynamic preload variables may enable the detection of volume change and fluid responsiveness in SB hypovolemic patients performing PB activity.

Comparison of antiallodynic effect of intrathecal morphine, brimonidine and rilmenidine between neuritis and ligation injury induced neuropathic pain / 대한마취과학회지

BACKGROUND: Mechanical allodynia is generally resulted from nerve damage by direct injury or inflammation. Thus, this study was designed to compare the antiallodynic effect of morphine, brimonidine and rilmenidine in two models of neuropathic pain, that is, induced by nerve ligation and neuritis. METHODS: Rats were prepared with tight ligation of the L5/L6 spinal nerves (SNL group) or with Freund's complete adjuvant (FCA) administration evoked sciatic inflammatory neuritis (SIN group). Antiallodynic effects by intrathecal morphine, brimonidine and rilmenidine were measured by applying von Frey filaments to the lesioned hind paw. Thresholds for withdrawal response were assessed and converted to % MPE to obtain an effective dose 50% (ED 50) and a dose response curve. RESULTS: Either SNL group or SIN group showed marked mechanical allodynia in the lesioned hind paw. Antiallodynic effects of morphine were different between two groups. That is ED 50 was 0.16 microgram (SIN) and 8.12 microgram (SNL), and dose response curve of the SIN group shifted left from that of the SNL group. The difference between SIN and SNL groups was statistically significant (P < 0.05). With the brimonidine or rilmenidine administration, ED 50 s were 0.12 microgram (SNL) and 0.37 microgram (SIN) and 2.16 microgram (SIN) and 11.46 microgram (SNL), respectively. And the shift to left of dose response curve from the SNL group is more prominent with rilmenidine administration. CONCLUSIONS: These results suggest morphine and rilmenidine showed a better effect on reducing the mechanical allodynia induced by FCA administration.

Pneumomediastinum due to inadvertent bladder perforation during transurethral resection of the prostate : A case report / 대한마취과학회지

Transurethral resection of the prostate (TURP) is a common procedure for managing benign prostatic hyperplasia (BPH), and this procedure is associated with low complication rates. Bladder perforation is an unusual complication of TURP, and it may create an air leak into the retroperitoneal space. Here we describe a case of pneumomediastinum, pneumoretroperitoneum and subcutaneous emphysema that were all due to a bladder perforation that occurred during performing TURP in a 74-year-old male patient with BPH.

Effects of magnesium infusion on hemodynamic and autonomic changes in healthy volunteers / 대한마취과학회지

BACKGROUND: Magnesium has been used for treatments and preventions of various situations, such as cardiovascular disease and pre-eclampsia. And it also used for decreasing demands of anesthetics and analgesics during anesthesia. Activity of autonomic nervous system has important roles for homeostasis of cardiovascular system, and its dysfunction affects mortality and morbidity. Because there are few reports about effects of magnesium infusion on autonomic nervous system, we investigated effects of magnesium infusion on hemodynamic and autonomic changes using variable autonomic function tests in healthy volunteers. METHODS: Hemodynamic parameters, heart rate variability, blood pressure variability, and baroreflex sensitivity were evaluated before and after magnesium infusion of 30 mg/kg during 20 min in twenty healthy volunteers. Cold face test, valsalva maneuver were also performed before and after magnesium infusion. RESULTS: Low-frequency components of blood pressure variability decreased after magnesium infusion (P = 0.026). There were no significant differences in blood pressure, heart rate, cardiac output, stroke volume, total peripheral resistance, heart rate variablility and baroreflex sensitivity between before and after magnesium infusion. Increases of diastolic blood pressure during cold face test decreased significantly after magnesium infusion (P = 0.022). In addition, no significant hemodynamic and autonomic changes were found during valsalva maneuver. CONCLUSIONS: Central sympathetic vasomotor tone decreased after magnesium infusion of 30 mg/kg during 20 min in healthy volunteers. However, it had no effects on parasympathetic system and baroreflex sensitivity.

Fatal Renal Rupture as a Rare Complication of Percutaneous Nephrolithotomy / 대한마취과학회지

Percutaneous nephrolithotomy (PNL) is a safe and effective procedure commonly performed to remove renal stones. Although PNL is associated with low morbidity, unexpected complications may occur. We describe here a 44-year-old male patient with recurrent renal stones who experienced a renal rupture and massive bleeding following PNL. Left nephrectomy and intensive treatment did not improve the patient's condition, and he died 14 days later as a result of multi-organ failure.

Anesthetic Experience of Percutaneous Nephrolithotomy for Renal Calculi in a Patient with Lesch-Nyhan Syndrome: A case report / 대한마취과학회지

Lesch-Nyhan syndrome (LNS) is a rare, X-linked recessive inherited disorder caused by a deficiency of the enzyme hypoxanthine-guanine-phophoribosyltransferase, leading to excessive purine production and elevation of uric acid. Clinical manifestations include mental retardation, spasticity, choreathetosis, compulsive self-mutilation, renal calculi followed by obstructive nephropathy, and arthritis. Patient with LNS may have increased risk of aspiration pneumonia, acute renal failure and unexpected sudden death. We accomplished successful general anesthesia in a case of LNS requiring percutaneous nephrolithotomy due to renal calculi.

The Effect of Sevoflurane Anesthesia on the Phase Relationship between Systolic Blood Pressure and Heart Rate / 대한마취과학회지

BACKGROUND: The phase relationship indicates the time delay between the input signal (systolic blood pressure, SBP) and output signal (R-R interval, RRI). In contrast to the awake state, little is known about the effects of general anesthesia on the phase shift. In the present study, we tested the hypothesis that sevoflurane anesthesia causes a phase change between the two signals. METHODS: We assessed changes in phase, coherence, and baroreflex sensitivity between SBP and RRI by the use of transfer function analysis in 50 ASA 1 patients during the awake state and during end-tidal 2% sevoflurane-50% N2O anesthesia. RESULTS: SBP and RRI decreased significantly during sevoflurane anesthesia (P < 0.001). The phase in the low frequency (LF) region remained unchanged, but the phase in the high frequency (HF) region changed significantly from -29.52 +/- 50.70 to 27.28 +/- 80.22 degrees during sevoflurane anesthesia (P < 0.001). Coherence and baroreflex sensitivity between the two signals in the LF and HF regions decreased significantly during sevoflurane anesthesia (P < 0.001, respectively). CONCLUSIONS: We found that in the HF region and not in the LF region, sevoflurane anesthesia provokes the shift of the SBP-RRI phase relationship, suggesting that this change is inconsistent with a vagally mediated response.

Fatal Cardiac and Pulmonary Embolisms during Radical Nephrectomy and Inferior Vena Cava Thrombectomy: A case report / 대한마취과학회지

Intraoperative pulmonary embolism can result in severe hemodynamic instability, including cardiac arrest. Therefore, immediate diagnosis and proper treatment are required. We report a case of the acute cardiac and pulmonary embolisms during radical nephrectomy and inferior vena cava (IVC) thrombectomy in a patient with renal cell carcinoma with thrombus in the IVC. We diagnosed the cardiac embolism intraoperatively using the transesophageal echocardiogram, and performed emergent cardiac and pulmonary embolectomies immediately. After the surgery, the patient was discharged without any complication.

The Hemodynamic Effects of Remifentanil as an Induction Agent in Cardiac Surgery

BACKGROUND: Remifentanil may be advantageous during induction of anesthesia in patient with heart disease because of rapid onset and hemodynamic stability. Some study reported that remifentanil showed complications such as profound bradycardia, severe hypotension and rigidity. The purpose of this study is to investigate the hemodynamic changes and side effects of remifentanil by using the methods of bolus administration during induction of anesthesia in cardiac surgery. METHODS: Fifty eight patients of ASA physical status 2~3 undergoing cardiac surgery were enrolled into 3 groups. We administered no remifentanil in Group A, 5microg/kg of remifentanil in Group B and 10microg/kg of remifentanil in Group C. After bolus administration of remifentanil over 30 sec, we infused 0.2microg/kg/min of remifentanil continuously. All group received continuous infusion of 100microg/ kg/min of propofol. After loss of consciousness, 0.15 mg/kg of vecuronium was administered. After the Bispectral index (BIS) value became lower than 60, intubation was done. Mean arterial pressure, heart rate, the incidence of cough, jaw and chest wall rigidity, and BIS value were measured initially and 1, 2, 3, 4, 5 minutes before intubation and 1, 2, 3, 4, 5 minutes after intubation. RESULTS: Mean arterial pressures of group B and C were significantly lower than those of group A (P < 0.05). Heart rate was similar among the groups. Group C showed a greater incidence of jaw rigidity (77%) compared with group A (35%) and group B (35%) (P < 0.05). The incidence of chest wall rigidity (66%) in group C was greater than group A (5%) and group B (15%) (P < 0.05). CONCLUSIONS: Remifentanil used as an induction agent (5microg/kg or 10microg/kg) may cause hypotension and jaw, chest wall rigidity with improper ventilation.

Appropriate Thresholds of Systolic Blood Pressure and R-R Interval for Assessment of Baroreflex Sensitivity by the Sequence Method during Sevoflurane Anesthesia / 대한마취과학회지

BACKGROUND: The sequence method of determining baroreflex sensitivity (BRSSEQ) has been reported to correlate poorly with the phenylephrine method of determining BRS in individuals with attenuated BRS. Inhalation anesthetics are also known to decrease BRS. We therefore assessed the effect of varying the systolic blood pressure (SBP) and R-R interval (RRI) thresholds on BRSSEQ values and compared these results with the BRS obtained by the modified Oxford technique (BRSMODOX). METHODS: The average number of valid sequences and BRSSEQ values were derived by varying the SBP threshold from 0.5 to 2.5 mmHg and the RRI threshold from 1 to 6 ms, and the relation of BRSSEQ values to BRSMODOX values using sequential administration of nitroprusside and phenylephrine was assessed in 40 healthy individuals during sevoflurane anesthesia. RESULTS: Increasing either the SBP thresholds or RRI thresholds resulted in a decrease in the number of valid sequences. As the SBP thresholds were decreased and the RRI thresholds were increased, BRSSEQ values increased. When the SBP threshold exceeded 1 mmHg, no significant correlations were observed between BRSSEQ and BRSMODOX values. Significant correlations between the two methods were observed for an SBP threshold of 0.5 mmHg and RRI thresholds of 1, 2, 3 and 4 ms. Biases between the two methods were 2.1, 2.1, 0.4, and 0.4 ms/mmHg for 0.5 mmHg and 1, 2, 3 and 4 ms. CONCLUSIONS: These findings suggest that adjusting the SBP threshold to 0.5 mmHg and the RRI threshold to 3 or 4 ms may improve BRSSEQ validity during sevoflurane anesthesia, when compared to BRSMODOX.

Left Atrial Thrombus Diagnosed by Transesophageal Echocardiography Immediately after Induction in a Patient with Middle Cerebral Artery Infarction: A case report / 대한마취과학회지

Stroke is one of the most common causes of death; in particular, cardiac source of embolism may be responsible for 15-20% of ischemic strokes. Here we report a case of left atrial thrombus diagnosed by transesophageal echocardiography (TEE) immediately after induction of general anesthesia in a patient with infarction of the middle cerebral artery. In this case, an emergent craniectomy was cancelled and medical treatment was performed. This case report shows that TEE taken in the operating room may play an important role in the change of treatment plan in a patient displaying acute mental change.

Pulmonary Embolism in a Patient of Renal Cell Carcinoma with Inferior Vena Cava Thrombus : A case report

Renal cell carcinoma (RCC) involves frequently the inferior vena cava (IVC). As effective treatment of RCC with IVC thrombus is currently lacking, aggressive surgical treatment may be considered. However, this procedure can result in fatal complications such as pulmonary embolism. We experienced a case of pulmonary embolism diagnosed, not by intraoperative transesophageal echocardiography, but by a computed tomography scan taken just after radical nephrectomy with IVC thrombectomy in a 63-year-old patient with RCC extending to the IVC.