Pivalizza, Evan G MBChB, FFASA, BTh; Patel, Janki MD; Warters, Robert D. MD, FASA Author Information

Background Colorectal cancer is a leading cause of cancer-related death. Adenomas and serrated polyps are precursors of colorectal cancer, with serrated polyps being more difficult to detect during colonoscopy. The relationship between propofol use and polyp detection remains unclear. The authors investigated the association of propofol-based versus mild–moderate sedation on adenoma and serrated polyp detection during colonoscopy. Methods This retrospective cohort study used observational data from the New Hampshire Colonoscopy Registry. Patients aged greater than 50 yr with screening or surveillance colonoscopies between January 1, 2015, and February 28, 2020, were included. Exclusions were diagnostic examinations, no sedation, missing pathology data, and poor bowel preparation. Multivariate logistic regression was used to evaluate differences in polyp detection between propofol and moderate sedation in the full sample while adjusting for covariates. Propensity score adjustment and clustering at the endoscopist level were used in a restricted sample analysis that included endoscopists and facilities with between 5% and 95% propofol sedation use. Results A total of 54,063 colonoscopies were analyzed in the full sample and 18,998 in the restricted sample. Serrated polyp prevalence was significantly higher using propofol (9,957 of 29,312; 34.0% [95% CI, 33.4 to 34.5%]) versus moderate sedation (6,066 of 24,751; 24.5% [95% CI, 24.0 to 25.1%]) in the full sample and restricted samples (1,410 of 4,661; 30.3% [95% CI, 28.9 to 31.6%] vs. 3,690 of 14,337; 25.7% [95% CI, 25.0 to 26.5%]). In the full sample multivariate logistic regression, propofol was associated with higher neoplasm (adjusted odds ratio, 1.25 [95% CI, 1.21 to 1.29]), adenoma (odds ratio, 1.07 [95% CI, 1.03 to 1.11]), and serrated polyp detection (odds ratio, 1.51 [95% CI, 1.46 to 1.57]). In the restricted sample using inverse probability of treatment weighted propensity score adjustment and clustering at the endoscopist level, an attenuated but statistically significant effect size was observed for serrated polyps (odds ratio, 1.13 [95% CI, 1.07 to 1.19]), but not for adenomas (odds ratio, 1.00 [95% CI, 0.95 to 1.05]) or any neoplastic lesion (odds ratio, 1.03 [95% CI, 0.98 to 1.08]). Conclusions Propofol sedation during colonoscopy may be associated with improved detection of serrated polyps, but not adenomas. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Abstract Background and Aims: Manual bag mask ventilation is a life saving skill. An investigation was made to compare two different facemasks used in bag mask ventilation, the standard and the novel Tao face mask, and evaluate the ability of novices to achieve adequate tidal volume. Methods: The study design was a crossover trial, which randomized forty medical students with no previous airway experience to learn bag mask ventilation with the standard mask and the Tao face mask. Primary outcome measures were mean and median tidal volume per mask, and secondary measures were hand area, age, gender, and order of mask usage. Results: Medical students who used the Tao mask first achieved significantly more tidal volume than those who used the standard mask first (p = 0.002). However, when comparing face masks that were used second, the tidal volume did not differ significantly between the two masks (p = 1.000). Greater tidal volume was achieved on the second attempt relative to the first attempt with each mask. There was significantly more tidal volume achieved with greater hand size with the standard mask, whether it was used first or second (p < 0.001 and p = 0.012 respectively). Greater hand size was associated with greater tidal volume in the Tao mask also, but only when used first (p < 0.001). When first attempting bag mask ventilation, inexperienced students achieved greater tidal volume with the Tao Mask. The results also suggest that hand size matters less when using the Tao Mask. Conclusion: When first attempting bag mask ventilation inexperienced students achieved greater tidal volume with the Tao Mask. The results also suggest that hand size matters less when using the Tao mask.

BACKGROUND: Manual positive pressure ventilation is an essential skill in a variety of clinical situations. The C&E technique is commonly used with standard facemasks to provide effective ventilation. The Tao mask is a novel design that allows a more ergonomic grip. A seal between the mask and face is made with downward pressure of the palm, centered on the mask, and jaw lift is achieved with 4 fingers centered under the mandible. The purpose of this study was to evaluate the safety and effectiveness of the Tao mask compared to a standard mask before and after the administration of neuromuscular blockade (NMB) using 2 previously established ventilation scales. METHODS: One hundred fifty-two patients >18 years of age who were scheduled for general anesthesia were recruited. All care team members were shown a brief instructional video on the use of the Tao mask. After induction of general anesthesia with a standardized protocol, each patient was ventilated with both the standard (Vital Signs #082510) and Tao masks and effectiveness was measured using the Han and Warters scales. This process was repeated after NMB. The sequence of masks was determined with a random-number generator. RESULTS: Tao mask ventilation scores were significantly better than standard mask scores on both the Han scale and the Warters scale before the administration of NMB (P < .001 for both). Tao mask scores were also significantly better than standard mask scores on the Warters scale after the administration of NMB (P < .001). However, there was no significant difference on the Han scale between the 2 mask types after NMB (P = .180). On the Warters scale, there were significantly fewer patients who were difficult to ventilate with the Tao mask than the standard mask before NMB (18 vs 40; P < .001) and after NMB (8 vs 17; P = .005). No adverse events were reported with either mask. CONCLUSIONS: Our results indicate that the Tao mask demonstrated equivalent safety and superior effectiveness compared to a standard mask. The study design favored the standard mask because all participating practitioners had multiple years of experience with the standard mask and no prior experience with the Tao mask. Since the incidence of inadequate mask ventilation goes up significantly with inexperienced operators, the improved effectiveness of the Tao mask could be even more profound with novice operators.

A 36-year-old African American with a medical history of nonanesthesia-related malignant hyperthermia (MH) who was taking chronic oral dantrolene therapy presented with right upper quadrant pain for a laparoscopic cholecystectomy. A multidisciplinary perioperative plan was implemented with the goal of avoiding triggering an MH episode or rhabdomyolysis. He developed a postoperative left brachial vein thrombus of unclear etiology, possibly related to dantrolene administration or his underlying susceptibility to MH.

BACKGROUND:Electrocardiogram (ECG) guidance to confirm accurate positioning of central venous catheters (CVC), placed before surgery in the operating room, is rarely used in the United States. We designed this randomized, controlled trial to investigate whether the use of this technique impacts the accuracy of CVC placement. METHODS:Patients in group ECG (n = 147) had a CVC placed using right-atrial ECG to guide catheter tip positioning. CVCs in group NO-ECG (n = 143) were positioned without this technique. RESULTS:Overall, guidewire-ECG control resulted in more correctly positioned CVCs (96% vs 76%, P < or = 0.001) without increasing placement time. Significantly more CVCs were placed in the middle of the superior vena cava in group ECG (P < or = 0.001), although placement into the right atrium or right ventricle and into other vessels occurred significantly more often in group NO-ECG (P < or = 0.001). Twenty patients in group NO-ECG required repositioning of their CVC after surgery, whereas this maneuver was necessary only in three patients in group ECG (P < or = 0.001). CONCLUSIONS:ECG guidance allows for more accurate CVC placement, and should be considered to increase patient safety and reduce costs associated with repositioning procedures.

In Response: We appreciate the kind comments of Dr. Pivalizza et al. For these studies, the primary anesthesiology provider of the anesthesia care team was recorded in data collection (1,2). Since medical students and others are “inserted” into the anesthesia care team during their rotation, we did not stratify the data by medical student, paramedical staff, etc. As we reported in the Discussion, teaching can occur in other parts of the perioperative period, such as maintenance of anesthesia or postanesthetic debriefing, for example. In the current economic climate, this study strongly suggests that other educational paradigms for resident teaching may be required. These include more extensive use of computerized instruction and simulators. Alternatively, faculty can prioritize resident instruction for a given case, such that the necessary aspects of important principles of induction are emphasized (“the teachable moment”) during the induction phase and other aspects of patient care are developed at other time points during the perioperative period. Elizabeth A. Davis, RCDS Paul Barash, MD Department of Anesthesiology Yale University School of Medicine and Yale-New Haven Hospital New Haven, CT [email protected]

Correction of coagulation defects with plasma transfusion did not decrease the need for intraoperative red blood cells (RBC) transfusions during liver transplantations. On the contrary, it led to a hypervolemic state that resulted in an increase of shed blood. As well, plasma transfusion has been associated with a decreased one-year survival rate. The aim of the present prospective survey was to evaluate whether anesthesiologists could reduce intraoperative RBC transfusions during liver transplantations by changing their anesthesia practice, more specifically by maintaining a low central venous pressure (CVP), through restriction of volume replacement, elimination of all plasma transfusion and by using intraoperative phlebotomy during the transplantation. One hundred consecutive liver transplantations were prospectively studied during a two-year period and were compared to a retrospective series (1998-2002). A low CVP was maintained in all patients prior the anhepatic phase. Coagulation disorders were not corrected preoperatively, intraoperatively, or post-operatively unless uncontrollable bleeding. Phlebotomy and Cell Saver (CS) were used following pre-established criteria. Independent variables were analyzed in a univariate and multivariate fashion. The mean number of intraoperative RBC units transfused was 0.4 +/- 0.8. No plasma, platelets, albumin, or cryoprecipitate were transfused. Seventy-nine percent of the patients received no blood products during their liver transplantation. The average final hemoglobin value was 85.9 +/- 17.8 g/L. In 57 patients (58.2%), intraoperative phlebotomy and CS were used either together or separately. The one-year year survival rate was 89.1%. Logistic regression showed that avoidance of plasma transfusion, starting hemoglobin value and phlebotomy were significantly linked to liver transplantation without RBC transfusion. In conclusion, the avoidance of plasma transfusion and maintenance of a low CVP prior to the anhepatic phase were associated with a decrease in RBC transfusions during liver transplantations. Previous reports indicating that it is neither useful nor necessary to correct coagulation defects with plasma transfusion prior to liver transplantation are further corroborated by this prospective survey. We believe that this work also supports the practice of lowering CVP with phlebotomy in order to reduce blood loss, during liver dissection, without any deleterious effect.

To the Editor: Luckner et al., reported transesophageal echocardiography (TEE) documented systolic anterior motion of the mitral valve and left ventricular outflow obstruction in 3 noncardiac surgical patients (1). We are concerned that, in their haste to insert the TEE, the authors have digressed from sound anesthesia care. Vigorous resuscitation with crystalloids, colloids, and vasoconstrictors are standard responses in the hypovolemic patient, and the TEE diagnoses did not alter logical management in any of the cases. Case 1. The patient was hypertensive, elderly, with bilateral femur fractures, all associated with intravascular volume contraction, and received a large propofol dose (2.5 mg/kg). Resuscitation was with crystalloid only and an α + β agonist. Only after TEE was colloid and phenylephrine (logical pure α-agonist) initiated. Case 2. Extensive bleeding was diagnosed, with minimal crystalloid resuscitation. Only after TEE was colloid administered. A pure vasoconstrictor would also have been a logical simultaneous choice. Case 3. This elderly, hypertensive patient received a large dose (2.5 mg/kg) of propofol. Hypotension would be anticipated and resuscitation with crystalloids, colloids, and phenylephrine would be appropriate choices, but were only initiated after TEE. TEE may be of value in hypotensive noncardiac surgical patients, but insertion and focus on TEE images should not detract from logical clinical decisions. TEE-guided management in these cases should have been no different from that already instituted. Evan G. Pivalizza, MD Robert D. Warters, MD Peter Szmuk, MD Department of Anesthesiology, University of Texas Medical School-Houston, Houston, TX, [email protected]

12. Remove personal protection equipment in ante-room or inside patient's room.The PAPR system consists of a belt-mounted powered air purifier (Figure, left) with a HEPA filter, connected via a tube to a light-weight head-piece (Figure, right).The HEPA filter removes particles of 0.3-15 mm with an efficiency of 98-100%. 4 We have several years experience in using the PAPR system in the bronchoscopy suite and there are no documentation of disease transmission to health-care workers.The PAPR system has been suggested by the World Health Organization and the Center for Disease Control for SARS protection.It takes time to setup properly (steps 1-7).Therefore, it is crucial to have advance warning of patients requiring intubation.Furthermore, staff involved in intubation must be trained and familiar with the personal protection equipment so that it can be applied properly and expediently (steps 5-7); and removed properly to avoid contamination.As traditional respiratory and contact precautions have been shown to provide inadequate protection against SARS, we have developed this protocol which offers improved protection.The intubation protection protocol should be utilized whenever suspected SARS or infectious patients are encountered.