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.

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.
Airway Management ; Brain ; Congenital Abnormalities ; Humans ; Intubation ; Intubation, Intratracheal ; Laryngoscopy ; Mandible ; Mouth ; Neck ; Prognathism* ; Retrognathia* ; Surgery, Plastic

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.
Anoxia* ; Bronchi ; Gravitation ; Lung* ; One-Lung Ventilation* ; Oxygen ; Perfusion ; Pulmonary Artery ; Thoracic Surgery ; Trachea ; Ventilation

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.
Airway Management ; Apnea ; Bronchi ; Humans ; Intubation ; Lung ; Male ; One-Lung Ventilation ; Sutures ; Thoracoscopy ; Thoracotomy ; Trachea ; Ventilation

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.
Anesthesia ; Cardiomyopathy, Hypertrophic ; Echocardiography, Transesophageal ; Hemodynamics ; Humans ; Hypotension ; Mitral Valve ; Pericardial Effusion

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.
Anesthesia ; Anesthesia, General ; Arterial Pressure ; Blood Pressure ; Humans ; Hypotension ; Incidence ; Leg ; Prospective Studies ; ROC Curve ; Stroke Volume ; Thoracic Surgery ; Vascular Access Devices

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.
Analgesia, Epidural ; Blood Vessels ; Catheters ; Epidural Space ; Glycosaminoglycans ; Humans ; Intraoperative Complications ; Intraoperative Period ; Male ; Punctures ; Thoracotomy

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.
Adult ; Aged ; Androstanols/adverse effects/pharmacology ; Anesthetics/adverse effects/pharmacology ; Anesthetics, Inhalation/adverse effects/*pharmacology ; Blood Pressure/drug effects ; Etomidate/adverse effects/pharmacology ; Female ; Heart/*drug effects ; Heart Rate/drug effects ; Humans ; Isoflurane/adverse effects/*analogs & derivatives/pharmacology ; Male ; Middle Aged ; Piperidines/adverse effects/*therapeutic use ; Protective Agents/adverse effects/*therapeutic use

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.
Anesthesia ; Cardiac Output ; Coronary Artery Bypass, Off-Pump ; Cross-Over Studies ; Hemodynamics ; Hip ; Humans ; Hypotension ; Knee ; Leg ; Perfusion ; Prospective Studies ; Shock ; Supine Position ; Tertiary Healthcare

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.
Aged ; Aspirin/*administration & dosage ; Cohort Studies ; Coronary Artery Bypass, Off-Pump/*adverse effects ; Coronary Disease/*surgery ; Drug Resistance ; Female ; Humans ; Male ; Middle Aged ; Myocardial Infarction/etiology ; Myocardial Reperfusion Injury/*prevention & control ; Platelet Aggregation Inhibitors/*administration & dosage ; Postoperative Hemorrhage/etiology ; Preoperative Care/methods ; Prospective Studies ; Stroke/etiology ; Troponin I/blood