Increase In Peak Airway Pressure Research Articles

Glutamine maintains the stability of alveolar structure and function after lung transplantation by inhibiting autophagy

Excessive autophagy may lead to degradation and damage of alveolar epithelial cells after lung transplantation, eventually leading to alveolar epithelial cell loss, affecting the structural integrity and function of alveoli. Glutamine (Gln), a nutritional supplement, regulates autophagy through multiple signaling pathways. In this study, we explored the protective role of Gln on alveolar epithelial cells by inhibiting autophagy. In vivo, a rat orthotopic lung transplant model was carried out to evaluate the therapeutic effect of glutamine. Ischemia/reperfusion (I/R) induced alveolar collapse, edema, epithelial cell apoptosis, and inflammation, which led to a reduction of alveolar physiological function, such as an increase in peak airway pressure, and a decrease in lung compliance and oxygenation index. In comparison, Gln preserved alveolar structure and function by reducing alveolar apoptosis, inflammation, and edema. In vitro, a hypoxia/reoxygenation (H/R) cell model was performed to simulate IR injury on mouse lung epithelial (MLE) cells and human lung bronchus epithelial (Beas-2B) cells. H/R impaired the proliferation of epithelial cells and triggered cell apoptosis. In contrast, Gln normalized cell proliferation and suppressed I/R-induced cell apoptosis. The activation of mTOR and the downregulation of autophagy-related proteins (LC3, Atg5, Beclin1) were observed in Gln-treated lung tissues and alveolar epithelial cells. Both in vivo and in vitro, rapamycin, a classical mTOR inhibitor, reversed the beneficial effects of Gln on alveolar structure and function. Taken together, Glnpreserved alveolar structure and function after lung transplantation by inhibiting autophagy.

Changes in endotracheal tube cuff pressure with the changes in peak airway pressures during total laparoscopic hysterectomy and pelvic surgeries. A prospective and observational study

Background: The abdominal insufflation and changes in endotracheal tube (ETT) cuff pressure due to creation of pneumoperitoneum and changes in patient positioning during laparoscopic abdominal surgeries have not been explored thoroughly. Aims and Objectives: The aim of our study was to see the changes in ETT cuff pressures during creation, maintenance, release of pneumoperitoneum, and during surgical positioning. Materials and Methods: A total of 60 patients were finally taken for study. Written informed consent was taken for participation in the study as well as consent for surgery. Inclusion criteria were patients of age above 30 years, American society of anesthesiology physical status 1 and 2, patients undergoing total laparoscopic hysterectomy requiring trendelenburg positioning. Exclusion criteria were patients with pre-existing pulmonary or cardiac disease, patients with pre-existing vocal cord palsy, goitre or any other airway or thoracic pathology, pregnant or lactating females, BMI more than 25 or <18.5. Changes of cuff and airway pressures before and after abdominal insufflation in supine position and after head-down or head-up positioning were analyzed and compared. Results: Baseline cuff pressure after manual inflation was 28.85±11.4 cm H2O. Significant correlation was observed between change in cuff pressure and increase in peak airway pressure at the end of the surgery (P<0.05). Serial measurements of ETT cuff pressure, peak airway pressure, and ETCO2 were significantly increased compared to baseline (P<0.05). Conclusion: Pneumoperitoneum in Trendelenburg position increases ETT cuff pressure probably due to increase in airway pressure. Therefore, it seems advisable to include routine monitoring of ETT cuff pressure. Objective adjusted measurement of cuff pressure and airway pressures is recommended for such surgeries.

AutoFlow® (volume-guaranteed mode) versus volume-controlled ventilation for the laparoscopic surgery with BlockBuster supraglottic airway: A randomized controlled trial

Abstract Background and Aims: Supraglottic airway devices used in laparoscopic surgeries must be efficient to counter the increased peak airway pressure (PAWP) and airway leakage that can occur in laparoscopic surgeries. Hence, the implication of AutoFlow in ventilator strategy is propounded nowadays that facilitates low PAWP and high dynamic compliance to achieve targeted tidal volume and end-tidal carbon dioxide (ETCO2). BlockBuster™ Laryngeal mask furnishing minimum airway leak. The primary objective was to compare PAWP using the two modes of ventilation through the BlockBuster LMA after intubation, pneumoperitoneum, and Trendelenburg position. The secondary objective was to observe hemodynamic vitals. Methodology: In this single-center randomized controlled trial, we recruited 80 American Society of Anesthesiologists grade I and II adult patients undergoing elective laparoscopic surgeries. They were randomized by computer-generated method into two groups: volume-controlled AutoFlow® (VCAF) and volume-controlled (VC) group. Ventilation settings for both groups set to tidal volume 5–6 ml/kg of predicted body weight, positive end-expiratory pressure 5 cm H2O, I: E ratio 1:2, and respiratory rate 12–16/min to maintain targeted ETCO2 of 30–35 cm H2O. Intraabdominal pressure was set to 14 mmHg during pneumoperitoneum and 15° Trendelenburg position. Results: Mann–Whitney U-test for continuous variables and t-test for categorical variables. Data were presented as median (interquartile range). P <0.05 was considered statistically significant. During laparoscopic surgeries with BlockBuster™ PAWP at pneumoperitoneum was (20 cm H2O vs. 27 cm H2O) and Trendelenburg position (19 cm H2O vs. 27 cm H2O) was significant lower with VCAF (AutoFlow® ventilation) than with VC (P < 0.05). Conclusion: PAWP is significantly low in AutoFlow mode as compared to volume control mode with BlockBuster LMA. In addition, LMA BlockBuster provides good sealing pressure.

BUBBLING OVER: A CASE OF SUBCONJUNCTIVAL EMPHYSEMA AND PNEUMOMEDIASTINUM FOLLOWING LAPAROSCOPIC PROSTATECTOMY

BUBBLING OVER: A CASE OF SUBCONJUNCTIVAL EMPHYSEMA AND PNEUMOMEDIASTINUM FOLLOWING LAPAROSCOPIC PROSTATECTOMY

Adverse event using Medtronic NIM™ EMG endotracheal tube on a patient receiving anesthesia for hemithyroidectomy: a case report

BackgroundThe neural integrity monitor (NIM) electromyogram (EMG) endotracheal (ET) tube is a widely used device to monitor neural response through muscle activity. It is helpful in surgical procedures with high risk of damaging delicate structures in the head and neck. This case provides a thorough analysis of an adverse event that was encountered in the operating room, which others can hopefully learn from.Case presentationWe are reporting a case in which a patient undergoing hemithyroidectomy had experienced an adverse event using the Medtronic NIM™ EMG endotracheal tube. After successful induction and intubation, confirming the proper positioning of the electrode wires was necessary before the incision could be made. Upon reexamination, the patient suddenly became difficult to ventilate with increased peak airway pressure, decreased tidal volume, and end tidal CO2. This episode lasted approximately 15 min and the patient’s condition remained stable despite low tidal volumes. The problem was unexpectedly resolved upon deflation of the cuff of the ET tube.ConclusionsThere are several similar reports of these endotracheal tubes causing obstruction, especially those in which overinflation of the cuff caused cuff herniation and blockage of the Murphy eye and the bevel. It is currently believed that the design of this tube allowed for the obstruction to occur. The patient’s short body habitus may have also been a small contributing factor. The distance that the electrodes must sit within the vocal cords to the tip of the bevel is longer in this type of ET tube compared with a standard ET tube. The distance from the true vocal cords to where the cuff sits in the trachea is also greater in this model NIM EMG tube. There was no confirmation of the exact obstructive process that took place, however, confirming the tube and cuff positioning would have been optimal.

A prospective observational study on changes in endo-tracheal tube cuff pressure and its correlation with airway pressures during various stages of robotic pelvic surgeries.

Background and Aims:Robotic surgeries often require a relatively long duration of pneumo-peritoneum and trendelenburg position which may accentuate changes in endo-tracheal tube (ETT) cuff pressure leading to pressure related complications. The aim of this study was to analyze changes in ETT cuff pressures during various stages of pneumo-peritoneum and surgical positioning and its correlation with airway pressure changes.Material and Methods:A prospective observational study was planned after approval of institutional review board on 60 patients undergoing elective robotic pelvic surgery requiring head down position. Baseline cuff pressure was adjusted to 25 cm H2O. ETT cuff pressure, peak airway pressure and end tidal CO2 (ETCO2) was measured at various time intervals before and after pneumo-peritoneum and head down. Ventilatory parameters were kept fixed after baseline setting. Those requiring any change were excluded. Pearson’s coefficient was used for correlation and ANOVA for trend of parameters at different time intervals (P value <0.05 was considered significant).Results:Baseline cuff pressure after manual inflation was 46.2 ± 17.4 cm H2O. Significant correlation was observed between change in cuff pressure and increase in peak airway pressure at the end of the surgery (r = 0.4, P < 0.05). Serial measurements of ETT cuff pressure, peak airway pressure and ETCO2 were significantly increased compared to baseline (P < 0.05).Conclusion:Significant increases in ETT cuff pressure may be seen in robotic surgeries, with a positive correlation between change in cuff pressure and increase in airway pressures. Objective adjusted measurement of cuff pressure and airway pressures is recommended for such surgeries.

AutoFlow\xae versus volume-controlled ventilation for laparoscopic gynecological surgery using LMA\xae ProSeal\u2122: a randomized controlled trial

BackgroundDuring laparoscopic gynecological surgery, increased peak airway pressure (PAWP) can cause airway leak upon ventilation with the LMA® ProSeal™. We hypothesized that compared with the use of volume-controlled ventilation (VCV), the use of the AutoFlow® mode would decrease PAWP and airway leak during laparoscopic gynecological surgery with LMA ProSeal.MethodsThis single-center, randomized, controlled trial allocated 80 adult women undergoing elective laparoscopic gynecological surgery to one of two groups, namely, the AutoFlow group or the VCV group. Ventilation settings for both groups were 8 ml/kg of tidal volume and 5 cmH2O of positive end-expiratory pressure, and respiratory rate was adjusted to maintain end-tidal carbon dioxide at 35–40 mmHg. Airway leak, PAWP, and other ventilatory parameters and vital signs were recorded at four timepoints (1, 1 min after insertion of the gastric tube; 2, 2 min after intravenous administration of rocuronium 0.6–0.8 mg/kg; 3, 1 min after initiation of pneumoperitoneum; and 4, 1 min after changing to the Trendelenburg position). The primary outcome was PAWP during pneumoperitoneum and in the Trendelenburg position, whereas the secondary outcomes included PAWP at other timepoints and airway leak development. We used the Mann–Whitney U test for PAWP and Fisher’s exact test for comparing airway leak among the groups.ResultsData from 40 patients in the AutoFlow group and 39 in the VCV group were used for analysis. PAWP at pneumoperitoneum pressure and in the Trendelenburg position was significantly lower in the AutoFlow group than in the VCV group [median (interquartile range), 16 (15–18) cmH2O vs. 18 (17–19) cmH2O; P < 0.001]. Similarly, patients in the AutoFlow group showed lower PAWP at the other three timepoints measured. Airway leak occurred in four patients in the AutoFlow group and in two patients in the VCV group; however, this incidence was not significantly different (P = 0.68).ConclusionsEven though AutoFlow ventilation decreased PAWP, it did not reduce the incidence of airway leak compared with VCV during laparoscopic gynecological surgery with the LMA ProSeal.Trial registrationUMIN Clinical Trials Registry, identifier UMIN000023173.

Incidence of gastric insufflation at high compared with low laryngeal mask cuff pressure: A randomised controlled cross-over trial.

The success of ventilation with a laryngeal mask depends crucially on the seal between the mask and the periglottic tissue. Increasing the laryngeal mask's cuff volume is known to reduce oral air leakage but may lead to gastric insufflation. We hypothesised that a lower cuff pressure would result in less gastric insufflation. We sought to compare gastric insufflation with laryngeal mask cuff pressures of 20 cmH2O (CP20) and 60 cmH2O (CP60) during increasing peak airway pressures in a randomised controlled double-blind cross-over study. We also evaluated the incidence of gastric insufflation at the recommended peak airway pressure of 20 cmH2O or less and during both intermittent positive airway pressure and continuous positive airway pressure. After obtaining ethics approval and written informed consent, 184 patients ventilated via laryngeal mask received a stepwise increase in peak airway pressure from 15 to 30 cmH2O with CP20 and CP60 in turn. Gastric insufflation was determined via real-time ultrasound and measurement of the cross-sectional area of the gastric antrum. The primary endpoint was the incidence of gastric insufflation at the different laryngeal mask cuff pressures. Data from 164 patients were analysed. Gastric insufflation occurred less frequently at CP20 compared with CP60 (P < 0.0001). Gastric insufflation was detected in 35% of cases with CP20 and in 48% with CP60 at a peak airway pressure of 20 cmH2O or less. Gastric insufflation occurred more often during continuous than during intermittent positive airway pressures (P < 0.01). A laryngeal mask cuff pressure of 20 cmH2O may reduce the risk of gastric insufflation during mechanical ventilation. Surprisingly, peak airway pressure of 20 cmH2O or less may already induce significant gastric insufflation. Continuous positive airway pressure should be avoided due to an increased risk of gastric insufflation. The study was registered in the German Clinical Trials Register (DRKS00010583) https://www.drks.de.

Surgical Stabilization of a Cervical Fracture in a Patient with Ankylosing Spondylitis in the Sitting Position

Ankylosing spondylitis is a seronegative spondyloarthropathy promoting alteration of the integrity and biomechanics of the spine. This leads to a brittle and hyperkyphotic spine with an increased risk of cervical spine fracture. Cervical spine fractures in people with ankylosing spondylitis are often unstable three-column extension injuries that are managed with posterior long segment fusions. Kyphotic deformity, body habitus, and increased airway pressures complicate these procedures. A 65-year-old man presented with neck pain following a fall from a roof. He was found to have a displaced transverse three-column fracture of C6/7. The original plan was to perform a staged circumferential cervical fusion with anterior cervical fusion first to make prone positioning for posterior fusion safer. CT after anterior cervical fusion from C5 to C7 demonstrated improved alignment of the fractured posterior elements. Due to concern of increased peak airway pressures and awkward positioning, planned prone positioning for posterior approach was abandoned. A posterior long segment fusion from C4 to T3 was performed in the seated position. CT demonstrated the hardware was appropriately placed. The patient’s hospital course was uncomplicated, and he was followed up with cervical spine x-rays. Two years later, he denied neck pain or functional impairment and x-ray demonstrated healing of the fracture. Utilizing the sitting position for the posterior cervicothoracic fusion portion of a combined anterior-posterior approach can overcome complication-spurring positioning difficulties and provide proper surgical management of an unstable cervical spine fracture in a patient with ankylosing spondylitis.

Comparative evaluation of I-gel vs. endotracheal intubation for adequacy of ventilation in pediatric patients undergoing laparoscopic surgeries.

Background and Aims:The use of newer supraglottic devices has been extended to laparoscopic procedures. We conducted this study to compare and evaluate the efficacy of these two devices in pediatric laparoscopic surgeries.Material and Methods:Eighty children, 2–8 years of age, scheduled for elective short laparoscopic procedures were randomly allocated to the I-gel or endotracheal tube (ETT) group. Standard anesthesia protocol was followed for inhalational induction. I-gel or ETT was inserted according to the manufacturer's recommendations. Ventilation was set with tidal volume 10 ml/kg and a respiratory rate of 16/min. Carboperitoneum was achieved up to an intra-abdominal pressure of 12 mmHg.Statistical Analysis:The primary outcome variable was adequacy of ventilation (peak airway pressure, end-tidal CO2, minute ventilation, and SPO2). These variables were recorded after securing airway, after carboperitoneum and desufflation of the peritoneal cavity. The oropharyngeal leak pressures were also noted. Statistical analysis was done using SPSS software version 17.0. P <0.05 was considered statistically significant.Results:No significant difference was observed in the heart rate or mean arterial pressure. There was a significant increase in the PECO2 and peak airway pressure after creation of carboperitoneum. There was significant increase in minute ventilation in both groups after creation of carboperitoneum.Conclusion:To conclude, I-gel is comparable to endotracheal intubation in terms of adequacy of ventilation. The increase in peak airway pressures is less with I-gel. In addition, postoperative complications are fewer with I-gel.

Effect of Body Mass on Oxygenation and Intra-Abdominal Pressure When Using a Jackson Surgical Table in the Prone Position During Lumbar Surgery.

Prospective observational study. To test the hypothesis that different types of surgical frame and the patient's body mass index (BMI) can affect pulmonary compliance, intra-abdominal pressure (IAP), and oxygenation. The oxygenation index (PaO2/FiO2) and IAP are known to be associated with BMI when patients are in the supine position. However, there are few reports on the correlation between BMI, the oxygenation index, and IAP in the prone position, especially when a Jackson surgical table is used. Thirty-seven adult patients were divided into two groups according to BMI: normal-weight patients (n = 19, BMI: 18.5-24.9 kg m) and overweight patients (n = 18, BMI ≥ 25 kg m). After the induction of general anesthesia, patients were turned to the prone position onto either a Jackson surgical table (Mizuho OSI) or a general surgical table (MAQUET; foam pad, China). The patient's IAP, peak airway pressure, pulmonary dynamic compliance (Cdyn), and oxygenation index were recorded. In overweight patients, there was a greater increase in peak airway pressure and a greater decrease in Cdyn observed when a general surgical table was used compared with the Jackson surgical table. When the Jackson surgical table was used, there was a greater increase in the oxygenation index and a greater decrease in IAP. There was a significant negative correlation between the oxygenation index and BMI and a significant positive correlation between IAP and BMI in the prone position. Turning patients from the supine to the prone position during anesthesia results in an increase in the oxygenation index and a decrease in IAP. Both of these factors are dependent upon the type of surgical frame used and the patient's BMI. The reduction in IAP was particularly significant when a Jackson surgical table was used for overweight patients. 4.

Effects of Increasing Airway Pressures on the Pressure of the Endotracheal Tube Cuff During Pelvic Laparoscopic Surgery.

Tracheal tube cuff pressures exceeding the perfusion pressures of the tracheal mucosa have been associated with complications such as sore throat, tracheal mucosa ulcers, tracheal rupture, and subglottic stenosis. Despite appropriate inflation, many factors can increase the tracheal cuff pressure during mechanical ventilation. This prospective observational cohort study was designed to test the hypothesis that during a clinical model of decreasing respiratory compliance, the pressure within the endotracheal tube cuff will rise in direct relationship to increases in the airway pressures. Twenty-eight adult obese patients (BMI ≥30 kg/m) scheduled for elective laparoscopic gynecologic procedures were enrolled. All patients received general anesthesia utilizing endotracheal tubes with low-pressure high-volume cuffs. After baseline adjustment of the cuff pressure to 25 cm H2O, the airway pressures and endotracheal cuff pressures were continuously measured using pressure transducers connected to the anesthesia circuit and cuff pilot, respectively. Data on cuff and airway pressures, mechanical ventilation parameters, intraabdominal pressures, and degree of surgical table inclination were collected throughout the anesthetic procedure. General linear regression models with fixed and random effects were fit to assess the effect of increases in airway pressures on cuff pressure, after adjusting for covariates and the clustered structure of the data. The mean (standard deviation) age and body mass index were 42.2 (8.8) years and 37.7 (5.1) kg/m, respectively. After tracheal intubation, the cuffs were overinflated (ie, intracuff pressures >30 cm H2O) in 89% of patients. The cuff pressures significantly changed after concomitant variations in the airway pressures from a mean (standard error) value of 29.6 (1.30) cm H2O before peritoneal insufflations, to 35.6 (0.68) cm H2O after peritoneal insufflation, and to 27.8 (0.79) cm H2O after peritoneal deflation (P < .0001). The multilevel mixed regression models revealed that after controlling for clustering of the data (at the patient and study phase levels) and covariates, increased peak airway pressures were significantly associated with increased pressures within the endotracheal cuff (coefficient [95% confidence interval], 0.25 [0.14-0.36]; P < .0001). Other variables associated with increasing endotracheal cuff pressure included degree of surgical table inclination (0.08 [0.04-0.12]; P = .0003) and I:E ratio of 1:1 (4.47 [2.10-6.83]; P = .0002). This clinical model of decreased respiratory compliance in mechanically ventilated patients reveals that the pressure within the endotracheal cuff significantly changes in direct relation to changes in the airway pressures. This finding may have clinical relevance in patients requiring prolonged use of high airway pressures.

Does restrictive fluid strategy during robotic pelvic surgeries obtund intraoperative rise in intraocular pressure?

Background:Robotic pelvic surgeries require steep Trendelenburg position which may result in rise in intraocular pressure (IOP).Aim:The aim of this study was to compare the changes that occur in IOP during robotic pelvic surgeries in steep Trendelenburg position with a restrictive intravenous fluid administration.Settings and Design:This prospective observational study was conducted in a tertiary care institution.Subjects and Methods:Twenty consenting patients scheduled for pelvic robotic gynecological surgeries were enrolled. All patients received general anesthesia following a standardized protocol. IOP was measured before induction of anesthesia, immediately after induction and intubation, at the end of surgery immediately after making the patient supine and immediately after extubation. Ringer's lactate was administered intravenously at a rate of 4 mL/kg/h targeting a mean arterial pressure of >65 mmHg and urine output of >0.5 mL/kg/h.Statistical Analysis Used:Paired t-test was used in this study.Results:There was a fall in IOP soon after induction from baseline which was not significant. Immediately, following intubation, there was a significant rise in IOP. At the end of surgery, though IOP remained high, it was not statistically significant. However, following extubation, IOP rose further and the difference from the baseline became statistically significant. Although there was a moderate increase in peak airway pressure and highest EtCO2 levels during Trendelenburg from baseline values, the differences were statistically insignificant.Conclusion:During robotic pelvic surgeries, adopting a restrictive intravenous fluid strategy with the maintenance of normal end-tidal carbon dioxide levels could abate effects of steep Trendelenburg position on IOP.

Application of PRVC in laparoscopic surgery

Objective: To discuss the clinical significance and value of PRVC by monitoring, comparing and studying pressure control (PC), volume control (VC) and pressure-regulated volume control (PRVC) ventilation modes during pneumoperitoneum. Methods: Ninety patients with laparoscopic cholecystectomy were randomly and equally divided into 3 groups (PC group, VC group and PRVC group). Esophageal pressure (PES), mean airway pressure (PAWM), peak airway pressure (PAP), arterial blood carbon dioxide partial pressure (PaCO 2 ), end-tidal carbon dioxide concentration in the expired air (ETCO 2 ), tidal volume (TV), mean arterial pressure (MAP) and heart rate (HR) were not only detected before pneumoperitoneum, but also in 5, 10, 15 and 20 minutes after pneumoperitoneum. Results: PES after pneumoperitoneum in VC mode was obviously higher than that in PC and PRVC groups. In 10 minutes after pneumoperitoneum, levels of PaCO 2 and ETCO 2 became increased obviously in PC and VC groups ( p < .05); levels of PaCO 2 and ETCO 2 were not only increased in PC group, but also the level of TV after pneumoperitoneum in PC group was significantly lower than that in the other two groups ( p < .05). Levels of PaCO 2 and ETCO 2 were increased in PC and VC groups after pneumoperitoneum, along with the increase of MAP and HR ( p < .05). After pneumoperitoneum, levels of MAP and HR in PRVC group were significantly lower than those in PC and VC groups ( p < .05). Conclusions: PRVC mode can effectively reduce the pneumoperitoneum-induced increase of PAWM, PAP and PES without the unusual increase of PaCO 2 and ETCO 2 during surgery, so as to guarantee the stability of vital signs in perioperative patients.

Effect of Pneumoperitoneum and Lateral Position on Oropharyngeal Seal Pressures of Proseal LMA in Laparoscopic Urological Procedures.

A sustained and effective oropharyngeal sealing with supraglottic airway is required to maintain the ventilation during laparoscopic surgery. Previous studies have observed the Oropharyngeal Seal Pressure (OSP) for Proseal Laryngeal Mask Airway (PLMA) after pneumoperitoneum in supine and trendelenburg position, where PLMA was found to be an effective airway device. This study was conducted with ProSeal LMA, for laparoscopic Urologic procedures done in lateral position. To measure OSP in supine and lateral position and to observe the effect of pneumoperitoneum in lateral position on OSP. Secondary objectives were to assess adequacy of ventilation and incidence of adverse events. A total number of 25 patients of American Society of Anaesthesiologists (ASA) physical status II and I were enrolled. After induction of anaesthesia using a standardized protocol, PLMA was inserted. Ryle's tube was inserted through drain tube. The position of PLMA was confirmed with ease of insertion of Ryle's tube and fibreoptic grading of vocal cords. Patients were then put in lateral position. The OSP was measured in supine position. This value was baseline comparison for OSP in lateral position and that after pneumoperitoneum. We assessed the efficacy of PLMA for ventilation, after carboperitoneum in lateral position (peak airway pressure, End Tidal Carbon dioxide (EtCO2), SPO2). Incidence of adverse effects (displacement of device, gastric insufflation, regurgitation, coughing, sore throat, blood on device, trauma) was also noted. The OSP was above Peak Airway Pressure (PAP) in supine (22.1±5.4 and 15.4±4.49cm of H2O) and lateral position (22.6±5.3 and 16.1±4.6). After pneumoperitoneum, which was in lateral position, there was statistically significant (p-value <0.05) increase in both PAP (19.96±4.015) and OSP (24.32±4.98, p-value 0.03). There was no intraoperative displacement of PLMA. There was no event of suboptimal oxygenation. EtCO2 was always within normal limits. Gastric insufflation was present in one patient. One patient had coughing and blood was detected on device. Three patients had throat discomfort post-operatively. In this study, Oropharyngeal seal pressures with PLMA were found to increase after pneumoperitoneum in lateral position. PLMA forms an effective seal around airway and is an efficient and safe alternative for airway management in urological laparoscopic surgeries done in lateral position.

Pneumothorax during Cardiomyotomy: Management

ABSTRACTLaparoscopic cardiomyotomy is the surgical mode of treatment for patients suffering from achalasia cardia. These patients are at a risk of developing intraoperative pneumothorax with hemodynamic and respiratory changes. We reported case of pneumothorax during laparoscopic cardiomyotomy. Patient developed hypotension, tachycardia, decreased air entry and increased peak airway pressure. We managed that case successfully. Hemodynamics was maintained with fluid and ephedrine. Patient was ventilated with 100% Oxygen and put on pressure cycled ventilator mode. Postoperatively patient was observed in ICU. While managing such cases, anesthetists should be aware of this complication and be vigilant.How to cite this articleNayak S. Pneumothorax during Cardiomyotomy: Management. Res Inno in Anesth 2016;1(2): 71-72.

Big cuff: Big problem.

Sir, Flexometallic/reinforced tubes are often used to replace the tracheostomy tubes during laryngectomy procedures. This report identifies the problem that can happen with the insertion of flexometallic tube (Rusch®, Teleflex Medical, Germany) through a low tracheostoma that was solved with the use of flexometallic tube from another manufacturer (UnoFlex™, Unomedical Sdn Bhd, Kedah, Malaysia). A 38-year-old male with carcinoma larynx was scheduled for total laryngectomy. He had already been tracheostomised with 8.0 mm ID Portex® tube. Following induction of anaesthesia, the Portex® tracheostomy tube was replaced with 8.0 mm ID flexometallic tube (Rusch®, Teleflex Medical, Germany) till its black mark was at the tracheostoma and the cuff was inflated. However, soon after this, auscultation of the chest revealed absence of air entry on left side and a drop in saturation to 92% with 100% O2, associated with sudden increase in peak airway pressures to 30 cm H2O leading to suspicion of endobronchial intubation. Therefore, the tracheal tube was gradually withdrawn with simultaneous auscultation for air entry on the left side. However, the tube appeared to remain endobronchial despite pulling the tracheal tube till proximal portion of its cuff was visible at the stomal site. At this juncture, we replaced the existing flexometallic tube (Rusch®, Teleflex Medical, Germany) with another 8.0 mm ID flexometallic tube from another manufacturer (UnoFlex™, Unomedical Sdn Bhd, Kedah, Malaysia) which was inserted until its cuff was well below the stomal site. This resulted in bilateral equal air entry, improvement in SpO2 to 100% and return of airway pressures to 16 cm H2O. Rest of the intraoperative period was uneventful and at the end of the surgery, the flexometallic tube was replaced by 8.0 mm ID Portex® tube. Most patients with carcinoma larynx scheduled for total laryngectomy would have been already tracheostomised or will require a preoperative tracheostomy. Proceeding to total laryngectomy with standard tracheostomy tube has got various problems like flange interfering with surgical site, difficulty in fixation and accidental dislodgement due to excessive drag by ventilator circuits. Whereas flexometallic tubes can be easily angled away from the surgical site without getting kinked and safely secured by suturing or taping it to the chest wall of the patient.[1] Though these tubes are certainly useful, there are various complications associated with these tubes like narrowing of the lumen and complete obstruction.[2,3,4] Flexometallic (Rusch®, Teleflex Medical, Germany) tubes usually contain a barrel shaped large cuff meant for a better seal and their use in patients with low tracheostomy may lead to endobronchial intubation as the distance between the proximal end of the cuff and the tip of the tube is relatively long (8 cm) compared to the other brand (UnoFlex™, Unomedical Sdn Bhd, Kedah, Malaysia) tube, where it is 6 cm [Figure 1]. Thus, changeover to UnoFlex™ tube, (which has smaller cuff) solved the problem of endobronchial intubation in our case. Though different manufacturers produce tubes with different cuff size for added advantage, this may become detrimental at specific situations. Figure 1 (a) Flexometallic (Rusch®) tube 8.0 mm ID. (b) Flexometallic (UnoFlex™) tube 8.0 mm ID. (c) Tracheostomy (Portex®) tube 8.0 mm ID In cases where low tracheostomy is anticipated, this problem can be avoided by the use of laryngectomy tubes. Laryngectomy (Montando®) tubes are reinforced cuffed tubes with J-configuration that have a short distance between cuff and tip and also short bevel to avoid endobronchial intubation.[5]

An add-on advantage of isoflurane graphical monitoring: Detection of intraoperative bronchospasm.

Sir, Post-intubation bronchospasm is one of the life-threatening complications of endotracheal intubation. Intraoperative bronchospasm is detected with the help of chest auscultation, increased peak airway pressure, hypoventilation, and upslope on capnograph (end-tidal CO2 [ETCO2]) along with downslope on sevoflurane graph during expiratory phase of respiratory cycle.[1] Advancement in bronchospasm detection methods, perioperative bronchodilator treatment and preventive measures have played a valuable role in reducing the incidence of perioperative bronchospasm and subsequently hypoxia along with hypercarbia leading to morbidity and mortality. We are reporting an interesting observation seen in newer machines that display isoflurane concentration as a volume time graph. An asthmatic patient with breast cancer was posted for modified radical mastectomy. Standard anaesthesia monitoring was initiated on Datex ohmeda Aestiva 5® (Datex-Ohmeda, Ohmeda Drive, PO Box 7550, Madison, Wisconsin 53707). General anaesthesia was induced with fentanyl 2 μg/kg and propofol 2 mg/kg; orotracheal intubation was facilitated by vecuronium 0.08 mg/kg. Patient was kept on mechanical ventilation. Anaesthesia was maintained with 100-200 μg/kg/min propofol infusion and 50% air-oxygen mixture. After 10 min patient developed an episode of bronchospasm as evidenced by increased airway pressure, rhonchi on auscultation and upsloping ETCO2. We increased oxygen to 100%, started isoflurane at concentration of 3% and added two puff of salbutamol metered dose inhaler in endotracheal tube; we observed downslope in isoflurane graph (end-tidal level of isoflurane [ETIso]) during expiratory phase of respiratory cycle corresponding to upsloping in ETCO2 graph [Figure 1A] (explained by slow and fast alveoli)during bronchospasm. Gradually as the airway pressure decreased along with disappearance of rhonchi, the ETIso graph also became normal (horizontal) along with ETCO2 graph [Figure 1B] within 20 ± 5 min. This left a smaller difference between the inspiratory fraction level of isoflurane (FiIso) and the ETIso. The difference in ETIso and FiIso is due to decrease in the number of slow alveoli on relief of bronchospasm. CO2 concentration being greater in expiration and isoflurane concentration being greater during inspiration results in mirror-image of the two waveforms. Figure 1 Figure ‘1A’ Upslope in capnograph during expiratory phase with corresponding downslope in isoflurane graph just below (isoflurane graph as the mirror image of capnograph) during bronchospasm. Figure ‘1B’ After reversal ... Like sevoflurane graph, isoflurane graph is also the mirror image of capnograph in both normal and bronchospasm conditions. We encountered similar graphical changes in 15 more cases till date in modern anaesthesia work stations with multichannel monitor like Datex ohmeda S/5 Avance®, Drager Pedius® (Drδger Medical GmbH 23542 Lόbeck Germany), Drager Fabius GS premium® and Datex ohmeda Aestiva 5®. Upward phase of isoflurane wave shows level of isoflurane in the breathing circuit at the starting of inspiration. Highest FiIso in the breathing circuit shows maximal mixing of isoflurane vapours coming from the vapouriser with the fresh gas. Intermediate downward phase of isoflurane wave shows the dilution of isoflurane in the circuit by the dead space at the starting of expiration isoflurane graph. Lowest ETIso shows maximum dilution of isoflurane by the exhaled alveolar gases at the end of expiration. Hence, isoflurane graphical monitoring is as useful as sevoflurane graphical monitoring along with capnograph in both detection and timely management of intraoperative bronchospasm to reduce the morbidity and mortality. We suggest the use of isoflurane graphical monitoring routinely in cases undergoing general anaesthesia with modern multi-parameter anaesthesia workstation in order to improve the sensitivity of monitoring thereby reducing the incidence of adverse respiratory events in operation room.

Endotracheal Tube Cuff Leaks

The consequences of endotracheal tube (ETT) cuff leak may range from a bubbling noise to a life-threatening ventilatory failure. Although the definitive solution is ETT replacement, this is often neither needed nor safe to perform. Frequently, the leak is not caused by a structural defect in the ETT. Cuff underinflation, cephalad migration of the ETT (partial tracheal extubation), misplaced orogastric or nasogastric tubes, wide discrepancy between ETT and tracheal diameters, or increased peak airway pressure can cause leaks around intact cuffs. Correction of these problems will stop the leak without ETT replacement. Alternatively, ETT cuff, pilot balloon, and inflation system damage due to inadvertent trauma or manufacturing defects may be responsible. Conservative management ideas (management without ETT replacement) were previously published to solve the problem. However, when a large structural defect is identified or conservative measures fail, ETT replacement becomes necessary. This can be performed with direct laryngoscopy if laryngeal visualization is adequate. A difficult exchange with possible airway loss should be anticipated, and prepared for, when there are signs and/or history of difficult intubation. A risk/benefit analysis of each individual situation is warranted before decisions are made on how best to proceed. Alternative back-up ventilation plans should be preformulated and the necessary equipment ready before the exchange. In this review, various management concerns and plans are discussed, and a simple algorithm to manage leaky ETT cuff situations is presented.

Bronchial obstruction by tumor embolus of contralateral lung during pneumonectomy: report of a case

Bronchial obstruction due to a tumor embolus of the contralateral lung during pneumonectomy is an uncommon and fatal complication. According to previous cases, a bronchial balloon of double-lumen endotracheal tube (DLT) could prevent a dislodged tumor from traveling to the contralateral lung. We experienced a tumor embolism from the bronchus with cancer to the other bronchus despite applying DLT. A 59-year-old male with endobronchial lung cancer underwent a left pneumonectomy. One-lung ventilation was established by the right-sided DLT. After a left bronchial division, a sudden increase of peak airway pressure and reduction of the expired tidal volume to 50 ml was observed. Intraoperative fiberoptic bronchoscopy showed a near total obstruction of the right main bronchus due to tumor emboli. It was not possible to remove the tumor embolus through bronchoscopic suction and forceps. Therefore, we reopened the left bronchial stump and successfully extracted tumor embolus under bronchoscopic guidance.