Cardiovascular manifestation of end-stage liver disease and perioperative echocardiography for liver transplantation: anesthesiologist’s view

Liver transplantation (LT) is the curative therapy for decompensated cirrhosis. However, anesthesiologists can find it challenging to manage patients undergoing LT due to the underlying pathologic conditions of patients with end-stage liver disease and the high invasiveness of the procedure, which is frequently accompanied by massive blood loss. Echocardiography is a non-invasive or semi-invasive imaging tool that provides real-time information about the structural and functional status of the heart and is considered to be able to improve outcomes by enabling accurate and detailed assessments. This article reviews the pathophysiologic changes of the heart accompanied by cirrhosis that mainly affect hemodynamics. We also present a comparative review of the diagnostic criteria for cirrhotic cardiomyopathy published by the World Congress of Gastroenterology in 2005 and the Cirrhotic Cardiomyopathy Consortium in 2019. This article discusses the conditions that could affect hemodynamic stability and postoperative outcomes, such as coronary artery disease, left ventricular outflow tract obstruction, portopulmonary hypertension, hepatopulmonary syndrome, pericardial effusion, cardiac tamponade, patent foramen ovale, and ascites. Finally, we cover a number of intraoperative factors that should be considered, including intraoperative blood loss, rapid reaccumulation of ascites, manipulation of the inferior vena cava, post-reperfusion syndrome, and adverse effects of excessive fluid infusion and transfusion. This article aimed to summarize the cardiovascular manifestations of cirrhosis that can affect hemodynamics and can be evaluated using perioperative echocardiography. We hope that this article will provide information about the hemodynamic characteristics of LT recipients and stimulate more active use of perioperative echocardiography.

The additional analgesic effects of transverse abdominis plane block in patients receiving low-dose intrathecal morphine for minimally invasive colorectal surgery: a randomized, single-blinded study

Purpose@#Intrathecal analgesia (ITA) and transverse abdominis plane block (TAPB) are effective pain control methods in abdominal surgery. However, there is still no gold standard for postoperative pain control in minimally invasive colorectal surgery. This study aimed to investigate whether the analgesic effect could be increased when TAPB, which can further reduce wound somatic pain, was administered in low-dose morphine ITA patients. @*Methods@#Patients undergoing elective colorectal surgery were randomized into an ITA with TAPB group or an ITA group. Patients were evaluated for pain 0, 8, 16, 24, and 48 hours after surgery. The primary outcome was the total morphine milligram equivalents administered 24 hours after surgery. The secondary outcomes were pain scores, ambulatory variables, inflammation markers, hospital stay duration, and complications within 48 hours after surgery. @*Results@#A total of 64 patients were recruited, and 55 were compared. There was no significant difference in morphine use over the 24 hours after surgery in the 2 groups (ITA with TAPB, 15.3 mg vs. ITA, 10.2 mg; P = 0.270). Also, there was no significant difference in pain scores. In both groups, the average pain score at 24 and 48 hours was 2 points or less, showing effective pain control. @*Conclusion@#ITA for pain control in patients with colorectal surgery is an effective pain method, and additional TAPB was not effective.

Influence of the Enhanced Recovery After Surgery Protocol on Postoperative Inflammation and Short-term Postoperative Surgical Outcomes After Colorectal Cancer Surgery

Purpose@#Many studies have shown that the enhanced recovery after surgery (ERAS) protocols improve postoperative surgical outcomes. The purpose of this study was to observe the effects on postoperative inflammatory markers and to explore the effects of a high degree of compliance and the use of epidural anesthesia on inflammation and surgical outcomes. @*Methods@#Four hundred patients underwent colorectal cancer surgery at 2 hospitals during 2 different periods, namely, from January 2006 to December 2009 and from January 2017 to July 2017. Data related to the patient’s clinicopathological features, inflammatory markers, percentage of compliance with elements of the ERAS protocol, and use of epidural anesthesia were collected from a prospectively maintained database. @*Results@#The complication rate and the length of hospital stay (LOS) were less in the ERAS group than in the conventional group (P = 0.005 and P ≤ 0.001, respectively). The postoperative white blood cell count and the duration required for leukocytes to normalize were reduced in patients following the ERAS protocol (P ≤ 0.001). Other inflammatory markers, such as lymphocyte count (P = 0.008), neutrophil/lymphocyte ratio (P = 0.032), and C-reactive protein level (P ≤ 0.001), were lower in the ERAS protocol group. High compliance ( ≥ 70%) was strongly associated with the complication rate and the LOS (P = 0.008 and P ≤ 0.001, respectively). @*Conclusion@#ERAS protocols decrease early postoperative inflammation and improves short-term postoperative recovery outcomes such as complication rate and the LOS. High compliance ( ≥ 70%) with the ERAS protocol elements accelerates the positive effects of ERAS on surgical outcomes; however, the effect on inflammation was very small.

Enhanced recovery after surgery: an anesthesiologist's perspective

Enhanced recovery after surgery (ERAS) is a multimodal and multidisciplinary approach to maintaining physiologic function and improving recovery for surgical patients. The ERAS protocol is based on a range of empirical evidence, and consensus ERAS guidelines for various surgical procedures have been published. The elements of the ERAS protocol include minimal preoperative fasting and carbohydrate treatment instead of overnight fasting; no routine use of preoperative bowel preparation; minimally invasive surgical techniques; standard anesthetic protocol; optimal fluid management rather than generous intravenous fluid administration; prevention and treatment of postoperative nausea and vomiting; active prevention of perioperative hypothermia; multimodal approaches to controlling postoperative pain; and early oral intake and mobilization. Implementation of ERAS shortened hospital stays by 30% to 50% and reduced postoperative complications by 50%. A recent study reported that, when patient compliance with the colorectal ERAS protocol was over 70%, 5-year mortality fell by 42% compared with when compliance was below 70%. Auditing process compliance and patient outcomes are key measures for assisting clinicians implementing the ERAS program. As a perioperativist, an anesthesiologist can play a crucial role in implementing the ERAS program and contribute to protocol establishment, auditing, team education and team leadership. While the ERAS protocol was first implemented for colorectal surgery, as a result of its efficacy, it is now being used in nearly all major surgical specialties.

Severe and persistent hypotension after simultaneous nephrectomy and kidney transplantation in patients with chronic renal failure caused by polycystic kidney disease: Two cases report

Patients with autosomal dominant polycystic kidney disease have significant morbidity due to large kidney size. Surgical extirpation of polycystic kidneys is frequently necessary to treat the morbidity or to obtain intraabdominal space for a graft kidney. Simultaneous bilateral nephrectomy and kidney transplantation are performed in many transplant centers to avoid the complications associated with anephric states such as anemia requiring blood transfusion, osteodystrophy, fluid overload, hyperkalemia, and congestive heart failure. However, the risk of postoperative complications after combined bilateral nephrectomy with kidney transplantation is relatively high, especially for cases in which the polycystic kidneys are huge. Here, we report two cases of severe and persistent hypotension during and after combined surgery which may have been caused by adrenal insufficiency or by sympathetic denervation and splanchnic vasculature decompression after the removal of huge polycystic kidneys.

Drug abuse associated with procedural sedation

Procedural sedation is now becoming more popular in South Korea along with the increases in cosmetic procedures and surgery, gastrointestinal endoscopy, and minimally invasive surgery, which have been accompanied by a surge in propofol abuse. The mechanism of potential abuse of sedatives and hypnotics share the common feature of all addictive drugs, in that they increase dopamine concentrations in target structures in the mesolimbic dopamine system. The abuse of sedatives and hypnotics occupies a small proportion of all substance abuse; however, propofol abuse is sharply increasing and is closely associated with procedural sedation in South Korea. Previous case reports have indicated that the majority of propofol abusers were health-care providers; however, recreational use of propofol is spreading among the general public. Lay people become addicted to propofol through repetitive procedural sedation or wrongful use by clinicians who are enticed by the promise of monetary gain. Illicit distribution of propofol accelerates abuse by lay people. The extremely narrow safety margin of propofol may cause a large number of fatal cases. Therefore, nationwide establishment of a policy to prevent the spread of propofol abuse is urgently needed.

Relationship of preoperative echocardiography and circulation in living donor liver transplantation

BACKGROUND: Echocardiography has been routinely performed before liver transplantation to screen perioperative risks due to cardiovascular complications. However, only limited echocardiographic indices have been used and have become familiar with clinicians. Here we aimed to evaluate the relationship between preoperative echocardiography and circulatory manifestations during living donor liver transplantation (LDLT). METHODS: Perioperative data including preoperative echocardiographic indices and intraoperative circulatory manifestations from 159 LDLT recipients (> or =18 years) were retrospectively collected. Relationships between individual echocardiographic indices and intraoperative circulatory manifestations were assessed by Pearson or Spearman correlation test. Intraoperative circulatory manifestations showing potential correlation with echocardiographic indices (r > or = 0.2 or or = 0.5 or < or =-0.5) were not found between echocardiographic indices and intraoperative circulatory manifestations, but intensive vasopressor coverage, urine output, sodium bicarbonate administration and last blood pH showed potential relations with at least one of preoperative echocardiographic indices. Early and late (atrial) ventricular filling velocity (E/A) ratios were lower in recipients with intensive vasopressor coverage, and left atrial diameter (LAD) were larger in recipients with last blood pH < 7.25. However, other parts of echocardiographic indices showed inconsistent relationships with formerly prevalent knowledge. CONCLUSIONS: Preoperative echocardiographic indices such as E/A ratio and LAD showed relationship with circulatory manifestations during LDLT. However, low correlation degrees and lack of evidence in reverse relationship with circulatory manifestations demands further studies focusing on such specific cardiac function.

Perioperative risk factors for prolonged mechanical ventilation after liver transplantation due to acute liver failure / 대한마취과학회지

BACKGROUND: Acute liver failure (ALF) is a rapidly progressing and fatal disease for which liver transplantation (LT) is the only treatment. Posttransplant mechanical ventilation tends to be more prolonged in patients with ALF than in other LT patients. The present study examined the clinical effects of prolonged posttransplant mechanical ventilation (PMV), and identified risk factors for PMV following LT for ALF. METHODS: We reviewed data of patients undergoing LT for ALF between January 2005 and June 2011. After grouping patients according to administration of PMV (> or = 24 h), donor and recipient perioperative variables were compared between the groups with and without PMV. Potentially significant factors (P or = grade III), intraoperative blood pressure fluctuation, and oliguria (< 0.5 ml/kg/h) were independent risk factors for PMV. CONCLUSIONS: PMV was associated with deleterious outcomes. Besides care for known risk factors including hepatic encephalopathy, meticulous attention to managing intraoperative hemodynamic circulatory status is required to avoid PMV and improve the posttransplant prognosis in ALF patients.

Propofol abuse among healthcare professionals

The number of healthcare professionals (HCPs) abusing propofol has been steadily growing, while recreational use of propofol among the general public has become a social concern. Propofol was once believed to be unsuited for the purpose of abuse because it wears off too quickly and induces unconsciousness more frequently than euphoria. However, studies have demonstrated the abuse potential of propofol. Animal studies have shown that propofol increases dopamine levels in the mesolimbic dopamine system, which is a putative mechanism of addiction for most addictive drugs. Behavior studies, not only with animals but also with human beings, have demonstrated that administration of propofol induces conditioned rewards and reinforcement. Although the incidence of propofol abuse among HCPs seems to be lower than that of abuse of common addictive substances, multiple articles and case reports have documented cases. Easy access to the drug is closely associated with its abuse among HCPs. In addition, the pharmacologic properties of propofol, specifically its short onset and offset, is one of reasons HCPs start to abuse this drug without any serious consideration and makes propofol abuse difficult to detect. To reduce propofol abuse among HCPs, we should develop a strict pharmacy control system for limiting access to propofol. Adopting radio-frequency identification system for controlled drugs could be an effective option. However, substance dependent HCPs are quite resourceful even in obtaining controlled drugs. Therefore, a multilateral approach to stem the rising tide of propofol abuse among HCPs is needed: a combination of preventative education, early identification and intervention, aggressive treatment, and consistent rehabilitation.

Anesthetic management for the insertion of a self-expandable metallic tracheal stent under venovenous extracorporeal membrane oxygenation / 대한마취과학회지

No abstract available.

Comparison of the Child-Turcotte-Pugh Classification and the Model for End-stage Liver Disease Score as Predictors of the Severity of the Systemic Inflammatory Response in Patients Undergoing Living-donor Liver Transplantation

The aim of this study was to evaluate and compare the Child-Turcotte-Pugh (CTP) classification system and the model for end-stage liver disease (MELD) score in predicting the severity of the systemic inflammatory response in living-donor liver transplantation patients. Recipients of liver graft were allocated to a recipient group (n = 39) and healthy donors to a donor group (n = 42). The association between the CTP classification, the MELD scores and perioperative cytokine concentrations in the recipient group was evaluated. The pro-inflammatory cytokines measured included interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha; the anti-inflammatory cytokines measured included IL-10 and IL-4. Cytokine concentrations were quantified using sandwich enzyme-linked immunoassays. The IL-6, TNF-alpha, and IL-10 concentrations in the recipient group were significantly higher than those in healthy donor group patients. All preoperative cytokine levels, except IL-6, increased in relation to the severity of liver disease, as measured by the CTP classification. Additionally, all cytokine levels, except IL-6, were significantly correlated preoperatively with MELD scores. However, the correlations diminished during the intraoperative period. The CTP classification and the MELD score are equally reliable in predicting the severity of the systemic inflammatory response, but only during the preoperative period.

Quality Control Program for Fresh Frozen Tissue and Its Results of Chonbuk National University Hospital National Biobank of Korea

BACKGROUND: Molecular tools for tissue profiling generally require collection of fresh frozen tissues (FFT) as sources of high-quality DNA and RNA. Nowadays, researchers carry out large-scale, multi-center studies and they request inter-institutional minimal intrinsic bias, some fundamental similarities, and the same standardized and validated procedures. METHODS: This study reports standardized quality control procedure for fresh frozen tissue of the National Biobank of Korea. RESULTS: The main procedures for quality control for FFT are as follows: records related to sample collection such as labeling of samples, transport temperature, lag time from excision of tissue to freezing, and sample size were reviewed for all fresh frozen samples. The stability of RNA and DNA in fresh frozen tissue was evaluated for 3% of collected samples and purity was assessed (ratio of the absorbance at 260 and 280 nm) as was integrity (agarose gel electrophoresis). Stained hematoxylin and eosin sections were reviewed by a pathologist to confirm the diagnosis and to assess how representative the frozen sample was. CONCLUSIONS: We introduced that the quality-control criteria for fresh frozen tissue of the NBK. We expect that this study contributes to standardization of collection, storage, and quality control of fresh frozen tissue.

Effects of Delay in the Snap Freezing of Colorectal Cancer Tissues on the Quality of DNA and RNA

PURPOSE: The success of basic molecular research using biospecimens strongly depends on the quality of the specimen. In this study, we evaluated the effects of delayed freezing time on the stability of DNA and RNA in fresh frozen tissue from patients with colorectal cancer. METHODS: Tissues were frozen at 10, 30, 60, and 90 minutes after extirpation of colorectal cancer in 20 cases. Absorbance ratio of 260 to 280 nm (A(260)/A(280)) and agarose gel electrophoresis were evaluated. In addition, the RNA integrity number (RIN) was assayed for the analysis of the RNA integrity. RESULTS: Regardless of delayed freezing time, all DNA and RNA samples revealed A(260)/A(280) ratios of more than 1.9, and all DNA samples showed a discrete, high-molecular-weight band on agarose gel electrophoresis. The RINs were 7.53 +/- 2.04, 6.70 +/- 1.88, 6.47 +/- 2.58, and 4.22 +/- 2.34 at 10, 30, 60, and 90 minutes, respectively. Though the concentration of RNA was not affected by delayed freezing, the RNA integrity was decreased with increasing delayed freezing time. CONCLUSION: According to the RIN results, we recommend that the collection of colorectal cancer tissue should be done within 10 minutes for studies requiring RNA of high quality and within 30 minutes for usual RNA studies.

The changes of central venous pressure by body posture and positive end-expiratory pressure / 대한마취과학회지

BACKGROUND: Central venous pressure (CVP) monitoring provides a useful estimate of the volume status of the systemic circulation. Both increase in the intrathoracic pressure by applying positive-end expiratory pressure (PEEP) and various patient positioning may commonly mislead the interpretation of CVP. We investigated the effect of body posture and different PEEPs on CVP in anesthetized patients. METHODS: Ninety-one patients (ASA I or II) scheduled for elective surgery with supine (50 patients), lateral decubitus (27 patients), or prone position (14 patients) were included. After induction of general anesthesia, CVP, mean arterial pressure (MAP), heart rate (HR), end-tidal CO2 (EtCO2) and peak inspiratory pressure (PIP) were measured under different PEEP conditions of 0, 5, 10, and 15 cmH2O in each body posture. RESULTS: CVP and PIP increased gradually by the increment of PEEP in patients with all positions. The magnitude of changes of CVP and PIP was significantly greater than other PEEP conditions when PEEP was 15 cmH2O, especially in prone position (P < 0.05). There were no differences in MAP, HR and EtCO2 during the increase of PEEP in all positions. CONCLUSIONS: These results suggest that PEEP as much as 15 cmH2O may alter reliability of CVP in estimating adequate circulatory volumes, especially in prone position.

Angiopoietin-1 variant, COMP-Ang1 attenuates hydrogen peroxide-induced acute lung injury

Reactive oxygen species (ROS) play a crucial role in acute lung injury. Tissue inflammation, the increased vascular permeability, and plasma exudation are cardinal features of acute lung injury. Angiopoietin-1 (Ang1) has potential therapeutic applications in preventing vascular leakage and also has beneficial effects in several inflammatory disorders. Recently developed COMP-Ang1 is more potent than native Ang1 in phosphorylating tyrosine kinase with immunoglobulin and EGF homology domain 2 receptor in endothelial cells. However, there are no data on effects and related molecular mechanisms of COMP- Ang1 on ROS-induced acute lung injury. We used hydrogen peroxide (H2O2)-inhaled mice to evaluate the effect of COMP-Ang1 on pulmonary inflammation, bronchial hyper-responsiveness, and vascular leakage in acute lung injury. The results have revealed that VEGF expression, the levels of IL-4, TNF-alpha, IL-1 beta, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 in lungs, the levels of hypoxia-inducible factor-1alpha (HIF-1 alpha) and NF-kappa B in nuclear protein extracts, phosphorylation of Akt, and vascular permeability were increased after inhalation of H2O2 and that the administration of COMP-Ang1 markedly reduced airway hyper-responsiveness, pulmonary inflammation, plasma extravasation, and the increases of cytokines, adhesion molecules, and VEGF in lungs treated with H2O2. We have also found that the activation of HIF-1a and NF-kappa B and the increase of phosphoinositide 3-kinase activity in lung tissues after H2O2 inhalation were decreased by the administration of COMP-Ang1. These results suggest that COMP-Ang1 ameliorates ROS-induced acute lung injury through attenuating vascular leakage and modulating inflammatory mediators.

Effect of Nalbuphine on Emergence Agitation and Recovery after Desflurane Anesthesia in Children for Strabismus Surgery / 대한마취과학회지

BACKGROUND: Emergence agitation frequently occurs after desflurane anesthesia in children.Nalbuphine, because of its sedative and analgesic properties, might be useful for the management of this side effect.We studied the effect of nalbuphine on recovery characteristics and emergence agitation after desflurane anesthesia in children for strabismus surgery. METHODS: 41 patients (3-14 yr) scheduled for pediatric strabismus surgery were included.All children received ketamine 0.5 mg/kg intravenously before entering the operating room.After intravenous induction with thiopental and rocuronium to facilitate endotracheal intubation, patients were randomly assigned to receive saline, or nalbuphine 0.2 mg/kg respectively. Anesthesia was maintained with desflurane 4-6% with N2O : O2 = 2 : 1.At the end of anesthesia, time to cough, extubation, movement, eye opening and discharge were recorded.Emergence agitation was recorded by three point rating scale. RESULTS: Agitation scores were significantly different between the two groups (P < 0.01).Time to extubation and movement were similar between two groups.Time to eye opening was significantly increased in nalbuphine group (P < 0.05).But, there was no difference in time to discharge from the recovery room to the ward between the two groups. CONCLUSIONS: In children undergoing strabismus surgery with desflurane anesthesia, nalbuphine 0.2 mg/kg administered immediately after induction reduced incidence of emergence agitation without delaying discharge from recovery room.

Assessment for the Quality of Recovery from General Anesthesia in Patients with Gynecologic Surgery / 대한마취과학회지

BACKGROUND: Quality of recovery, assessed by patients, is related to patients' satisfaction, and even to quality of life. Of numerous patient-based measures to evaluate the quality of recovery, a '40-item-quality of recovery (QoR-40)' has proved to be valid and reliable. Using this questionnaire, we evaluated the quality of recovery in the gynecological patients and tried to identify factors affecting the quality of recovery. METHODS: Patients undergoing gynecological surgery were asked to fill a questionnaire 8 to 9 p.m the day after the completion of anesthesia. Questionnaires were prepared after translation to Korean from 40-item-quality of recovery. From the anesthetic and recovery room records we collected data about patient's age, surgery types, anesthetic and surgical duration, recovery room stay, main anesthetic agents, and recovery room complications. RESULTS: A total of 383 patients completed the questionnaires. Patients aged under 40 got significantly lower QoR-40 scores than those aged over 40, especially in the dimension of pain (P < 0.05). Patients who had undergone laparoscopic surgery got higher scores than those had undergone non-laparoscopic surgery (P < 0.05). Patients who answered the questionnaires in more than 30 hours after the completion of anesthesia showed lower total scores than those who did in less than 30 hours, especially in the dimensions of emotional state and pain (P < 0.05). CONCLUSIONS: In gynecological patients, laparoscopic surgery improved quality of recovery. Quality of recovery was affected by age and survey time. Postoperative pain contributed to the decrease of the quality of recovery.

The effect of music on the effect-site concentration of propofol for loss of consciousness / 대한마취과학회지

BACKGROUND: Music reduces anxiety and the need for sedatives in preoperative patients. Currently, propofol is usually infused using target controlled infusion device. With the use of such a device, we investigated the effects of music on the effect-site concentration of propofol for loss of consciousness. METHODS: Sixty-five ASA 1 or 2 patients aged 35 to 55 years who were scheduled for general anesthesia were randomly allocated to either the control, music or headphone group. The control group patients were exposed to the ambient operating room atmosphere (n = 17), the music group patients listened to music (n = 25), and headphone group wore a headphone alone without listening to music (n = 23). Propofol was infused with a predetermined effect-site concentration and we determined loss of consciousness in patients by a verbal response and eyelash reflex for 3 minutes. Each concentration of propofol was predetermined by the up-and-down method with 0.4microgram/ml as the step size. RESULTS: Loss of consciousness was observed at a concentration of 4.20 +/- 0.25microgram/ml in the control group, 3.60 +/- 0.34microgram/ml in the music group, and 3.73 +/- 0.47microgram/ml in the headphone group. The effect-site concentration for loss of consciousness was significantly lower in the music group as compared to the control group (P < 0.05). The effect-site concentration in the headphone group, however, showed no statistical difference as compared to the control group (P = 0.117). CONCLUSIONS: Listening to music reduced overall propofol effect-site concentration for loss of consciousness that was required by patients.

Anesthesia for Surgical Fixation of the Fractured Neck of Femur in a Patient with Eisenmenger's Syndrome : A case report

Eisenmenger's syndrome consists of high pulmonary vascular resistance with reversed or bidirectional shunt at aortopulmonary, ventricular, or atrial level. Noncardiac surgery for a patient with this syndrome is challenging because both the perioperative morbidity and mortality are high. We describe the anesthetic management of a 66-year-old female patient with Eisenmenger's syndrome secondary to the tetralogy of Fallot (TOF), who was operated on for the fractured neck of her left femur. Anesthesia was induced with etomidate and sufentanil and was maintained with propofol and sufentanil without any inhalational anesthetics (total intravenous anesthesia). To maintain the systemic vascular resistance, we administered norepinephrine throughout the surgery and the postoperative care. The patient was discharged 20 days after the operation without any complications.

Effects of the modified blade on reducing the risk of dental trauma by novice laryngoscopists in anticipated difficult airway / 대한마취과학회지

BACKGROUND: Dental trauma is one of the most common complications during laryngoscopy, especially by novice. As the chance of making direct contact with the teeth is decreased during laryngoscopy, the chance of applying direct pressure to the teeth is decreased, thus the injury by the blade also can be decreased. The purpose of this study was to determine the effectiveness of a modified Macintosh blade on reducing dental contact and the risk of dental trauma by novice laryngoscopists in anticipated difficult airway. METHODS: Sixty-six patients scheduled for elective surgery were divided into Easy group and Difficult group according to Wilson's risk sum score. Laryngoscopy was performed twice on each patient by novice, once with a regular Macintosh 3 blade and once with a blade in which the flange was partially removed (Callander modification). The distance between the flange of the blade and the upper incisors at glottic exposure was measured. We compared the blade-tooth distances and the chance of directly contacting the tooth between two blades. RESULTS: The modified blade provided more distance than the regular Macintosh blade in both group (P < 0.001). It is also associated with decreased chance of directly contacting the teeth, especially in Difficult group (73.7% with regular blade vs 10.6% with the modified blade) (P < 0.001). CONCLUSIONS: The modified Macintosh blade used in this study proved to be an effective device for novice laryngoscopists in reducing likelihood of dental injuries in anticipated difficult intubation.