Driving pressure guided ventilation / 대한마취과학회지

Protective ventilation is a prevailing ventilatory strategy these days and is comprised of small tidal volume, limited inspiratory pressure, and application of positive end-expiratory pressure (PEEP). However, several retrospective studies recently suggested that tidal volume, inspiratory pressure, and PEEP are not related to patient outcomes, or only related when they influence the driving pressure. Therefore, this review introduces the concept of driving pressure and looks into the possibility of driving pressure-guided ventilation as a new ventilatory strategy, especially in thoracic surgery where postoperative pulmonary complications are common, and thus, lung protection is of utmost importance.

Severe hypoxemia during carinal resection in the lateral position under one-lung ventilation of a non-dependent lung: a case report / 대한마취과학회지

During one-lung ventilation (OLV) in the lateral position, the dependent, ventilated lung receives more blood flow than the non-dependent, non-ventilated lung owing to gravity, improving the match of ventilation and perfusion. Conversely, in the rare clinical situations when OLV is applied to the non-dependent lung, arterial oxygenation can get worse due to considerable shunt flow to the dependent non-ventilated lung. We report a case of severe hypoxemia during carinal resection under OLV of a non-dependent lung. In this case, OLV had to be applied to the non-dependent lung in the lateral position because the bronchus of the non-dependent lung was anastomosed with the trachea, whereas the bronchus of the dependent lung had already been resected for carinal resection. The subsequent hypoxemia resulting from the shunt flow to the dependent non-ventilated lung was treated successfully by ligating the pulmonary artery of the dependent lung.

Effects of airway evaluation parameters on the laryngeal view grade in mandibular prognathism and retrognathism patients

BACKGROUND: Failure to maintain a patent airway can result in brain damage or death. In patients with mandibular prognathism or retrognathism, intubation is generally thought to be difficult. We determined the degree of difficulty of airway management in patients with mandibular deformity using anatomic criteria to define and grade difficulty of endotracheal intubation with direct laryngoscopy. METHODS: Measurements were performed on 133 patients with prognathism and 33 with retrognathism scheduled for corrective esthetic surgery. A case study was performed on 89 patients with a normal mandible as the control group. In all patients, mouth opening distance (MOD), mandibular depth (MD), mandibular length (ML), mouth opening angle (MOA), neck extension angle (EXT), neck flexion angle (FLX), thyromental distance (TMD), inter-notch distance (IND), thyromental area (TMA), Mallampati grade, and Cormack and Lehane grade were measured. RESULTS: Cormack and Lehane grade I was observed in 84.2%, grade II in 15.0%, and grade III in 0.8% of mandibular prognathism cases; among retrognathism cases, 45.4% were grade I, 27.3% grade II, and 27.3% grade III; among controls, 65.2% were grade I, 26.9% were grade II, and 7.9% were grade III. MOD, MOA, ML, TMD, and TMA were greater in the prognathism group than in the control and retrognathism groups (P < 0.05). The measurements of ML were shorter in retrognathism than in the control and prognathism groups (P < 0.05). CONCLUSIONS: Laryngoscopic intubation was easier in patients with prognathism than in those with normal mandibles. However, in retrognathism, the laryngeal view grade was poor and the ML was an important factor.

Transection of a Coopdech bronchial blocker tip during bronchial resection for right upper lobectomy: a case report / 대한마취과학회지

A bronchial blocker (BB) is preferred for lung separation in patients with difficult airways. However, BBs, unlike double-lumen tubes, must be placed in the bronchus of the lung being operated on, hence can be damaged by surgical manipulation. Intubation was unexpectedly difficult in this male patient, so a Coopdech BB was placed in the right mainstem bronchus through a single-lumen tracheoscopic ventilation tube for a thoracoscopic right upper lobectomy. During the bronchial resection, however, the distal tip of the BB was transected and pinched in the staple line, so the staple line was partially opened, and the BB was withdrawn into the trachea. The opened bronchial stump was sutured manually under apnea without conversion to an open thoracotomy, and there was no significant air leakage through the suture line. This case underlines the importance of frequently evaluating the position of a BB during lung surgery.

Predictability of passive leg raising test on anesthesia-induced hypotension in patients undergoing cardiac surgery

BACKGROUND: Hypotension often occurs after induction of general anesthesia. Although preload status has been considered as an important factor for the occurrence of this hypotension, there have been inconsistent results on this topic. The dynamic preload parameters have not been studied as a predictor of hypotension, and therefore we hypothesized that the passive leg raising (PLR) test, a dynamic preload parameter, could predict anesthesia-induced hypotension and conducted a prospective clinical study. METHODS: In 40 patients undergoing elective cardiac surgery, mean arterial pressure (MAP), stroke volume variation, stroke volume (SV) and cardiac index (CI) were measured using arterial line and FloTrac(TM)/Vigileo(TM) system before, during and after PLR test, respectively. Occurrence of anesthesia-induced hypotension was recorded. The ability of PLR test to predict hypotension was evaluated by receiver operating characteristic (ROC) curve analysis. RESULTS: The incidence of hypotension was 90%, which includes 12.5% of refractory hypotension. Changes in MAP and CI induced by PLR test predicted hypotension (area under ROC curves: 0.722 and 0.788, respectively). Changes in SV and CI induced by PLR test predicted refractory hypotension (area under ROC curves: 0.863 and 0.789, respectively). CONCLUSIONS: Our results suggest that PLR test can predict hypotension and refractory hypotension occurring after induction of anesthesia in patients undergoing cardiac surgery.

Left ventricular outflow tract obstruction with systolic anterior motion of the mitral valve in patient with pericardial effusion caused by ascending aortic dissection: A case report / 대한마취과학회지

Left ventricular outflow tract (LVOT) obstruction with systolic anterior motion (SAM) of mitral valve is not only limited to patients with hypertrophic cardiomyopathy. A diagnosis of LVOT obstruction with SAM is important because conventional inotropic support may potentially aggravate hemodynamic deterioration. We present a case of LVOT obstruction with SAM in a patient who underwent an emergent surgery for ascending aortic dissection with pericardial effusion. The patient showed refractory hypotension after standard pharmacologic interventions during induction of anesthesia. Transesophageal echocardiography (TEE) revealed LVOT obstruction with SAM and it was managed appropriately under the guidance of TEE. Intraoperative TEE can play an important role in diagnosis and management of LVOT obstruction with SAM caused by pericardial effusion.

Effect-Site Concentration of Remifentanil for Minimizing Cardiovascular Changes by Inhalation of Desflurane

PURPOSE: This study aims to investigate the most appropriate effect-site concentration of remifentanil to minimize cardiovascular changes during inhalation of high concentration desflurane. MATERIALS AND METHODS: Sixty-nine American Society of Anesthesiologists physical status class I patients aged 20-65 years were randomly allocated into one of three groups. Anesthesia was induced with etomidate and rocuronium. Remifentanil was infused at effect-site concentrations of 2, 4 and 6 ng/mL in groups R2, R4 and R6, respectively. After target concentrations of remifentanil were reached, desflurane was inhaled to maintain the end-tidal concentration of 1.7 minimum alveolar concentrations for 5 minutes (over-pressure paradigm). The systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR) and end-tidal concentration of desflurane were measured for 5 minutes. RESULTS: The end-tidal concentration of desflurane increased similarly in all groups. The SBP, DBP, MAP and HR within group R4 were not significantly different as compared with baseline values. However, measured parameters within group R2 increased significantly 1-3 minutes after desflurane inhalation. The MAP within group R6 decreased significantly at 1, 2, 4, and 5 minutes (p<0.05). There were significant differences in SBP, DBP, MAP and HR among the three groups 1-3 minutes after inhalation (p<0.05). The incidence of side effects such as hyper- or hypo-tension, and tachy- or brady-cardia in group R4 was 4.8% compared with 21.8% in group R2 and 15.0% in group R6. CONCLUSION: The most appropriate effect-site concentration of remifentanil for blunting hemodynamic responses by inhalation of high concentration desflurane is 4 ng/mL.

Unsuspected intravascular migration of a thoracic epidural catheter in a thoracotomy patient: A case report

Thoracic epidural analgesia is the most effective method of managing post-thoracotomy pain. However, the catheter may be misplaced into the intrapleural, intercostal, subarachnoid, or intravascular space. Intravascular misplacement of a catheter can be detected by aspiration of blood or administration of a test dose of local anesthetic; however, these methods may result in a false-negative response. Moreover, a catheter placed in the epidural space may migrate into a blood vessel during the intraoperative period. Thus, the location of the catheter tip should always be determined before local anesthetic is administered. We report a case of intraoperative intravascular migration of a thoracic epidural catheter in a 32-year-old male who underwent left thoracotomy.

Hemodynamic effect of full flexion of the hips and knees in the supine position: a comparison with straight leg raising / 대한마취과학회지

BACKGROUND: Straight raising of the legs in the supine position or Trendelenburg positioning has been used to treat hypotension or shock, but the advantages of these positions are not clear and under debate. We performed a crossover study to evaluate the circulatory effect of full flexion of the hips and knees in the supine position (exaggerated lithotomy), and compare it with straight leg raising. METHODS: This study was a prospective randomized crossover study from the tertiary care unit at our university hospital. Twenty-two patients scheduled for off-pump coronary artery bypass surgery were enrolled. Induction and maintenance of anesthesia were standardized. Exaggerated lithotomy position or straight leg raising were randomly selected in the supine position. Hemodynamic variables were measured in the following sequence: 10 min after induction, 1, 5, and 10 min following the designated position, and 1 and 5 min after returning to the supine position. Ten min later, the other position was applied to measure the same hemodynamic variables. RESULTS: During the exaggerated lithotomy position, cerebral and coronary perfusion pressure increased significantly (P < 0.01) without a change in cardiac output. During straight leg raising, cardiac output increased at 5 min (P < 0.05) and cerebral and coronary perfusion pressures did not increase except for cerebral perfusion pressure at 1 min. However, the difference between the two groups at each time point in terms of cerebral perfusion pressure was clinically insignificant. CONCLUSIONS: Full flexion of the hips and knees in the supine position did not increase cardiac output but may be more beneficial than straight leg raising in terms of coronary perfusion pressure.

Gender difference and change of alpha1-adrenoceptors in the distal mesenteric arteries of streptozotocin-induced diabetic rats / 대한마취과학회지

BACKGROUND: The purpose of this study was to evaluate the gender-related changes in the function and distribution of alpha1-adrenoceptors in the distal mesenteric artery of streptozotocin (STZ)-induced diabetic rats at the level of alpha1-adrenoceptor subtypes. METHODS: Diabetes was induced by intravenous injection of STZ in a dose of 60 mg/kg through the tail vein in 8 week-old male or female Sprague-Dawley rats (n = 13/group). Age-matched normal rats (n = 15) were used as a control group. Four weeks after STZ injection, the change in mean arterial pressure caused by a 45degrees tilting was recorded. The alpha1-adrenoceptor subtypes mediating contractions of the distal mesenteric artery were investigated using the agonist, phenylephrine as well as subtype-selective antagonists including prazocin, 5-methylurapidil, and BMY 7378. The expression of alpha1-adrenoceptor subtypes of each artery was examined by immunofluorescence staining and western blotting using subtype selective antibodies. RESULTS: Compared with normal male rats, the contractile response to phenylephrine was decreased in the distal mesenteric artery in normal female rats. Moreover, a decrease in contractile force was observed in STZ-induced diabetic rats compared with age-matched controls. Western blotting revealed that there was the difference between normal male and female rats in manifestation of the alpha1D-adrenoceptor. In STZ-induced male and female diabetic rats, all alpha1-adrenoceptor subtypes were decreased in distal mesenteric arteries, compared with normal rats. CONCLUSIONS: There was the gender-related functional difference of alpha1-adrenoceptors in normal rats. In both male and female rats, diabetes decreased the contractile response in mesenteric arteries, which might be caused by the overall change in alpha1-adrenoceptor.

Anesthetic management of a patient with Mounier-Kuhn syndrome undergoing off-pump coronary artery bypass graft surgery: A case report / 대한마취과학회지

Mounier-Kuhn-syndrome patients have markedly dilated trachea and main bronchi due to an atrophy or absence of elastic fibers and thinning of smooth muscle layers in the tracheobronchial tree. Although this syndrome is rare, airway management is challenging and general anesthesia may produce fatal results. However, only a few cases have been reported and this condition is not widely known among anesthesiologists. We present the case of a tracheobronchomegaly patient undergoing an emergency off-pump coronary artery bypass. Although the trachea was markedly dilated with numerous tracheal diverticuli, there was an undilated 2 cm portion below the vocal cords found on the preoperative CT. Under a preparation of extracorporeal membrane oxygenation, we intubated and placed the balloon of an endotracheal tube (I.D. 9 mm) at this portion, and maintained ventilation during the operation. This case showed that a precise preoperative evaluation and anesthetic plan is essential for successful anesthetic management.

Preoperative Aspirin Resistance does not Increase Myocardial Injury during Off-pump Coronary Artery Bypass Surgery

We performed a prospective cohort trial on 220 patients undergoing elective off-pump coronary artery bypass surgery and taking aspirin to evaluate the effect of aspirin resistance on myocardial injury. The patients were divided into aspirin responders and aspirin non-responders by the value of the aspirin reaction units obtained preoperatively using the VerifyNow(TM) Aspirin Assay. The serum levels of troponin I were measured before surgery and 1, 6, 24, 48 and 72 hr after surgery. In-hospital major adverse cardiac and cerebrovascular events, graft occlusion, the postoperative blood loss and reexploration for bleeding were recorded. Of the 220 patients, 181 aspirin responders (82.3%) and 39 aspirin non-responders (17.7%) were defined. There were no significant differences in troponin I levels (ng/mL) between aspirin responders and aspirin non-responders: preoperative (0.04 +/- 0.08 vs 0.03 +/- 0.06; P = 0.56), postoperative 1 hr (0.72 +/- 0.87 vs 0.86 +/- 1.10; P = 0.54), 6 hr (2.92 +/- 8.76 vs 1.50 +/- 2.40; P = 0.94), 24 hr (4.16 +/- 13.44 vs 1.25 +/- 1.95; P = 0.52), 48 hr (2.15 +/- 7.06 vs 0.65 +/- 0.95; P = 0.64) and 72 hr (1.20 +/- 4.63 vs 0.38 +/- 0.56; P = 0.47). Moreover, no significant differences were observed with regard to in-hospital outcomes. In conclusion, preoperative aspirin resistance does not increase myocardial injury in patients undergoing off-pump coronary artery bypass surgery. Postoperative dual antiplatelet therapy might have protected aspirin resistant patients.

The diabetes-induced functional and distributional changes of the alpha 1-adrenoceptor of the abdominal aorta and distal mesenteric artery from streptozotocin-induced diabetic rats / 대한마취과학회지

BACKGROUND: The aim of this study was to evaluate the effect of diabetes on the function and distribution of vascular alpha1-adrenoceptors in the abdominal aorta and distal mesenteric artery from streptozotocin (STZ)-induced diabetic rats at the level of the alpha1-adrenoceptor subtypes. METHODS: Diabetes was induced by a single intravenous injection of STZ (60 mg/kg) in 8 week-old male Sprague-Dawley rats (n = 11). Age-matched normal rats (n = 14) were used as a control group. Four weeks after STZ injection, the tilting-induced change of the mean arterial pressure was recorded. The alpha1-adrenoceptor subtypes mediating the contractions of the distal mesenteric artery and abdominal aorta were investigated using the agonist phenylephrine and subtype-selective antagonists that included prazocin, 5-methylurapidil and BMY 7378. The expressions of the alpha1-adrenoceptor subtypes of each artery were examined by immunofluorescence staining using the subtype selective antibodies. RESULTS: The recovery of the mean arterial pressure was delayed after positional change in the diabetic rats. Compared with that of the normal rats, the contractile response to phenylephrine was increased in the abdominal aortas and it was decreased in the distal mesenteric arteries in the diabetic rats. In addition, compared with the normal rats, the fluorescent intensity of all the alpha1-adrenoceptor subtypes was increased in the abdominal aortas and it was decreased in the mesenteric arteries of the diabetic rats. CONCLUSIONS: Diabetes increased the contractility of the abdominal aorta in response to phenylephrine, yet diabetes decreased that of the mesenteric arteries in the STZ-induced diabetic rats. Those results are mainly based on the overall change of the alpha1-adrenoceptor, and not on the change of the specific alpha1-adrenoceptor subtypes.

Tracheal laceration during intubation of a double-lumen tube and intraoperative fiberoptic bronchoscopic evaluation through an LMA in the lateral position: A case report / 대한마취과학회지

A 76-year-old, 148-cm woman was scheduled for right upper lobectomy. A 32 Fr left-sided double lumen tube was placed using a conventional technique. Despite several attempts under fiberoptic bronchoscope-guidance, we could not locate the double lumen tube properly. We thus decided to proceed with the bronchial tube in the right mainstem bronchus. During surgery, 8-cm-long laceration was noted on the posterolateral side of the trachea. To check the possibility of laceration of the proximal trachea, the double lumen tube was changed to an LMA for use as a conduit for fiberoptic bronchoscopic evaluation in the lateral position. A plain endotracheal tube with the cuff modified and collapsed was re-intubated after evaluation. And then she was transferred to SICU.

One-lung ventilation with a bronchial blocker through a single-lumen endotracheal tube in a small woman: A case report

One-lung ventilation with a double-lumen endotracheal tube or a Univent(R) tube may be difficult or dangerous in small patients, children, and patients with anatomic abnormalities of the airway. The use of a bronchial blocker through a single-lumen endotracheal tube has been used successfully in such situations. A 69-year-old woman was scheduled for Ivor-Lewis operation and right upper lobectomy. She could not be intubated with a internal diameter 6.0 mm Univent(R) tube owing to narrow diameter of the vocal cord. We report a successful one-lung ventilation using a Uniblocker(R) through an adult-size single-lumen endotracheal tube in a small woman, who needed postoperative ventilator care.

Inhibition of Hypoxic Pulmonary Vasoconstriction of Rats by Carbon Monoxide

Hypoxic pulmonary vasoconstriction (HPV), a unique response of pulmonary circulation, is critical to prevent hypoxemia under local hypoventilation. Hypoxic inhibition of K+ channel is known as an important O2-sensing mechanism in HPV. Carbon monoxide (CO) is suggested as a positive regulator of Ca2+-activated K+ channel (BK(Ca)), a stimulator of guanylate cyclase, and an O2-mimetic agent in heme moiety-dependent O2 sensing mechanisms. Here we compared the effects of CO on the HPV (Po2, 3%) in isolated pulmonary artery (HPV(PA)) and in blood-perfused/ventilated lungs (HPV(lung)) of rats. A pretreatment with CO (3%) abolished the HPV(PA) in a reversible manner. The inhibition of HPV(PA) was completely reversed by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), a guanylate cyclase inhibitor. In contrast, the HPV(lung) was only partly decreased by CO. Moreover, the partial inhibition of HPV(lung) by CO was affected neither by the pretreatment with ODQ nor by NO synthase inhibitor (L-NAME). The CO-induced inhibitions of HPV(PA) and HPV(lung) were commonly unaffected by tetraethylammonium (TEA, 2 mM), a blocker of BK(Ca). As a whole, CO inhibits HPV(PA) via activating guanylate cyclase. The inconsistent effects of ODQ on HPV(PA) and HPV(lung) suggest that ODQ may lose its sGC inhibitory action when applied to the blood-containing perfusate.

Preoperative platelet response to collagen is associated with myocardial injury after off-pump coronary bypass graft in patients taking aspirin / 대한마취과학회지

BACKGROUND: We hypothesized that, even in patients taking aspirin, the variance of preoperative platelet response to collagen might be associated with myocardial injury during coronary artery bypass graft (CABG) surgery. Therefore, we evaluated the relationship between preoperative whole-blood aggregometry (WBA) by collagen and the postoperative myocardial injuries. METHODS: For 44 patients who were scheduled for elective off-pump CABG and taking aspirin, WBA was measured by the impedance method in the presence of collagen (2 mg/ml or 5 mg/ml) as stimulatory agents. After CABG, myocardial injury was evaluated by analysis of the creatine kinase (CK), creatine kinase-MB (CK-MB), and lactate dehydrogenase (LD), and by electrocardiography. RESULTS: High response group (n = 13) on preoperative WBA with collagen (2 and 5 mg/ml) showed significantly higher postoperative cardiac enzyme levels (CK, CK-MB and LD) than those of low response group (n = 31). CONCLUSIONS: In patients who take aspirin and undergoing off-pump CABG, the preoperative platelet response to collagen is correlated with postoperative myocardial injury.

Rupture of endotracheal tube cuff during robot-assisted endoscopic thyroidectomy: A case report / 대한마취과학회지

We encountered a case of a rupture of an endotracheal tube cuff during robot-assisted thyroid surgery in a 35-year-old male patient. Two hours after commencing surgery, the bellows of the ventilator were not filled and a rupture of the endotracheal tube cuff was suspected. Once the robot-manipulator is engaged, the position of the operating table cannot be altered without removing it from the patient. Reintubation with direct laryngoscopy was performed with difficulty in the narrow space between the patient's head and robot-manipulator without moving the robot away from the patient. The rupture of the endotracheal tube cuff was confirmed by observing air bubbles exiting from the balloon in water. The patient was discharged 3 days after surgery without complications. In robot-assisted thyroid surgery, a preoperative arrangement of the robot away from the patient's head to obtain easy access to the patient is essential for safe anesthetic care.

Perioperative cerebral infarct during cardiac surgery and changes in jugular venous O2 saturation and cerebral oximetry using near-infrared spectroscopy: A case report / 대한마취과학회지

Despite reductions in surgical mortality, neurologic sequelae remain a devastating complication after cardiac surgery with cardiopulmonary bypass. Neurologic complications may be induced by a massive air embolism during cardiopulmonary bypass, even with extensive monitoring. This report describes a patient who had a fatal cerebral infarct during aortic valve and ascending aorta replacement surgery. We monitored jugular venous O2 saturation (SjvO2) and cerebral oximetry using near-infrared spectroscopy in the perioperative period. The operation and anesthesia were uneventful until the deep hypothermic total arrest for the replacement of the ascending aorta. However, restarting the cardiopulmonary bypass after deep hypothermic total arrest produced a brief (less than 10 seconds) but large amount of air in the root cannula. At this time, although cerebral oximetry did not show any changes, the SjvO2 decreased to 21% for about 3 minutes and then normalized. At 8 hours after surgery, the patient showed seizures and severe edema in both cerebral hemispheres on the MRI. The patient died 21 days after surgery.

Use of an extracorporeal membrane oxygenation device during bilateral sequential lung transplantation: A case report / 대한마취과학회지

A 51-year-old man with dermatomyositis and severe interstitial pulmonary disease was planed for bilateral sequential lung transplantation under general anesthesia. He was supported by extracorporeal membrane oxygenation (ECMO) because of respiratory failure in the preoperative period. ECMO was used during induction and maintenance of anesthesia. After the reperfusion, ECMO was successfully weaned. Postoperatively, the patient was transferred to intensive care unit and discharged without serious complications.