09-03-15 Ventilator Management
Drs. Cases, Abrahams, Poovathoor
Curry Club 6:00 PM
Gao W, Liu DD, Li D, Cui GX. Effect of Therapeutic Hypercapnia on Inflammatory Responses to One-lung Ventilation in Lobectomy Patients. Anesthesiology. 2015 Jun;122(6):1235-52. [PubMed]
Weingarten TN, Whalen FX, Warner DO, Gajic O, Schears GJ, Snyder MR, Schroeder DR, Sprung J. Comparison of two ventilatory strategies in elderly patients undergoing major abdominal surgery. Br J Anaesth. 2010 Jan;104(1):16-22. [PubMed]
Dr. Caces gave a good review of the Gao et al article. This article found that with IV anesthesia, hypercapnia inhibited local and systematic inflammation. It also improved respiratory function after OLV in lobectomy patients without severe complications. There were 50 patients randomly receiving carbon dioxide at partial pressures of 35-45 mmHg or 60-70 mmHg for about 210 minutes. The primary outcome was the concentration of bronchoalveolar lavage fluid TNF-alpha in the collapsed lung and the ventilated lung. Secondary outcomes were the serum cytokine concentrations during the 3 day postop observation. Therapeutic hypercapnia lowered airway pressure but increased the compliance of PaO2/FiO2 after surgery. Severe inflammation can cause lung injury. The exact benefit of the therapeutic hypercapnia reducing inflammation is not known, but the authors surmised that the therapeutic hypercapnia may benefit patients by speeding recovery and reducing potential complications. One limitation was that continual long term testing of therapeutic hypercapnia was not performed. Another limitation was the exclusion of severe obstructive lung disease; these patients might have benefited from hypercapnia. The blinding in the paper was discussed as well as the importance of the primary outcome and how it can influence the how many subjects/patients are in the study. It is important to do a power analysis to determine the number of patients needed in each group.
Dr. Abrahams concisely discussed the Weingarten et al paper. In this study, open lung ventilation with recruitment maneuvers, tv 6 ml Kg and 12 cm H20 PEEP was compared to conventional ventilation with TV 10ml kg in patients >65 years old. Serum levels of IL -6 and Il -8 before and after surgery were monitored to see if the systemic inflammatory response to surgery depends on the ventilation. It was found that the lung recruitment strategy improved intraoperative oxygenation and lung mechanics. A limitation of the study was that several outcome variables were looked at but there were only 20 patients. Also systemic cytokine levels are not an accurate measurement of lung inflammation. There were no evidence for adverse effects, but once again n may have been too small. Because we do not know all the variables, we cannot estimate the sample size accurately. It was also discussed that physiologic PEEP of 5-6 may help with AutoPEEP.
10-08-15 Pediatric Anesthesia
Drs. Soohoo, K. Lee, Chandrakantan, and Seidman
Phyathai, Ronkonkoma 6:00 PM
Koyuncu O et al. Effect of carboxyhemoglobin on postoperative complications and pain in pediatric tonsillectomy patients. Paediatr Anaesth. 2015 Mar;25(3):247-52. [PubMed]
Moss JR et al. A multicenter, randomized, double-blind placebo-controlled, single dose trial of the safety and efficacy of intravenous ibuprofen for treatment of pain in pediatric patients undergoing tonsillectomy. Paediatr Anaesth. 2014 May;24(5) [PubMed]
Andersson H et al. Low incidence of pulmonary aspiration in children allowed intake of clear fluids until called to the operating suite. Paediatr Anaesth. 2015 Aug;25(8):770-7. [PubMed]
Dr. Lee gave an excellent review of the article by Moss et al. There were 161 patients enrolled in the study. Patients received either a single preoperative dose of 10mg .kg IV ibuprofen or a placebo normal saline. The primary endpoint was the number of doses and amount of postoperative fentanyl administered postoperatively for rescue anesthesia. There was a decrease in the number of postoperative doses and amount of fentanyl given after surgery in the IV ibuprofen group given at induction. Tonsillectomy as a procedure was discussed and how postoperative pain can be significant. Some limitations to the study were that it allowed fentanyl use during surgery which may have affected ability to detect a greater opioid sparing effect of the IV ibuprofen. It was discussed that the study was underpowered. In addition, some patients had a larger weight and this may have meant that they had not received therapeutic doses of ibuprofen. Because dexamathasone was given, further studies may be required in which kids are not routinely given corticosteroids. Historically bleeding levels with tonsillectomy were higher than today. The use of Ibuprofen vs ketorolac was discussed. Today, most would not choose to do a study comparing the two because of the effect of ketorolac on bleeding. Pharmacological properties of both ibuprofen and ketorolac were compared.
The article by Koyuncu et al was also discussed by Dr. Lee. CO is the product of burning solid fuel such as wood, crop, residues, coal, etc for heating and cooking from stoves and smoking. There appeared to be a link between COHb concentration and pain. This study tested the hypothesis that high COHb concentrations result in more postoperative complications and pain after tonsillectomy and therefore use more analgesic use. 100 kids were in the study divided in high (64 patients) CO exposure vs low (36). High preoperative COHb concentrations were found to be associated with higher postoperative complications and pain. Some of the limitations in the study are: the use of a relatively new noninvasive device to evaluate carboxyhemoglobin versus blood concentration, length of surgery and surgeons included were not elaborated on in the study as well as using children's parents/caregivers to note accurate passive smoking at home. It was discussed that children are actually better than thought at differentiating pain vs nausea. Amazingly they can separate the two. There was also discussion that the increased nausea, increased pain and increased laryngospasm were interestingly sympathetically mediated phenomena. Also patient autonomy was discussed with regard to making decisions of care. Children are a protected class so this has less weight here. It was noted that it is probably best to discuss all with patients and put risk stratification in perspective for the patient/patient's parents.
Dr. Soohoo gave an excellent review of the Andersson et al paper. The study was done to determine if incidence of perioperative pulmonary aspiration in pediatric patients allowed unlimited intake of clear fluids prior to GA. This was a retrospective chart review of 10015 pediatric anesthetics. Aspiration occurred 3 cases (0.03%). A perioperative pulmonary aspiration event was aspiration of gastric contents occurring during induction of anesthesia, during the procedure, or after extubation in the operating room. This study divided aspiration events into pulmonary and suspected pulmonary aspiration. Dr. Soohoo gave us the historical perspective of aspiration from 1847 to the present. Snow in 1858, Balfour in 1862, Mendelson in 1946, Roberts in 1974, & James in 1984. It was noted that the aspiration events in kids is small for various reasons: Children are a basically healthy population vs the adults coming to the OR , there are more elective surgeries in children vs emergency cases and specialty trained physicians will take care of these children. It was discussed that this study could help change our clinical practice since it gives some evidence regarding children allowed fluid intake up to the OR. It is always hard to make changes but if the clinical evidence is there, then perhaps it will make it easier for that change to occur.
11-12-15 Obstetric Neuraxial Anesthesia
Drs. Samir Shah, Moy, Costa and Steinberg
SB Galleria 6:00 PM
Camann W. Obstetric Neuraxial Anesthesia Contraindicated? Really? Time to Rethink Old Dogma. Anesth Analg. 2015 Oct;121(4):846-8. [PubMed]
Goodier CG et al. Neuraxial Anesthesia in Parturients with Thrombocytopenia: A Multisite Retrospective Cohort Study. Anesth Analg. 2015 Oct;121(4):988-91. [PubMed]
Bauchat JR et al. Labor Analgesia Consumption and Time to Neuraxial Catheter Placement in Women with a History of Surgical Correction for Scoliosis: A Case-Matched Study. Anesth Analg. 2015 Oct;121(4):981-7. [PubMed]
Peralta F et al. The Relationship of Body Mass Index with the Incidence of Postdural Puncture Headache in Parturients. Anesth Analg. 2015 Aug;121(2):451-6. [PubMed]
Arzola C et al. Bedside Gastric Ultrasonography in Term Pregnant Women Before Elective Cesarean Delivery: A Prospective Cohort Study. Anesth Analg. 2015 Sep;121(3):752-8. [PubMed]
Dr. Samir Shah gave an excellent review of the articles by Goodier et al., Bauchat et al. and the editorial by Camann. The articles and editorial discussed commonly seen problems in Labor and Delivery. Goodier et al. supported relative maternal safety for neuraxial anesthesia in parturients with mild thrombocytopenia and alerts us to the maternal complication rate associated with avoidance of neuraxial anesthesia. There is no general agreement regarding the platelet count threshold for withholding neuraxial anesthesia. The risk of epidural hematoma may outweigh the benefit of neuraxial anesthesia. Pain is treated suboptimally and the likelihood that General anesthesia will be used increases. This can result in further maternal morbidity. The authors recommend a national registry of procedures performed in thrombocytopenic patients with the data managed by a national organization. We do perform these cases. It was mentioned that there is no accepted value for the cutoff because it depends on the clinical picture of the patient. Moreover, platelet function is more important than the number of platelets. A thromboelastogram gives a good measure of this but may not be available in a stat situation.
The Bauchat article on scoliosis suggested that neuraxial labor analgesia should be offered to parturients with previous spine surgery. The patient should be made aware that there can be technical difficulty with placement resulting in surgical anesthesia failure. This is consistent with what patients are advised in our L&D. Many are seen for consults prior to their admission. Today surgical techniques and hardware have evolved. The lower lumbar segments and epidural space are spared and better derotation of the spine is achieved by use of the lateral implants outside the spinal canal. The epidural space may be more accessible via the midline approach and scar tissue is reduced compared with prior surgical methods. It is seen from these articles and the editorial that we need to rethink our approach. Case scenarios were reviewed as well as other patient situations with preeclampsia, congenital heart disease such as tetrology of fallot, multiple sclerosis, and chiari malformations. We do offer neuraxial anesthesia to such patients and as always a case by case apporoach is best as suggested by Goodier. General anesthesia in the parturient has a high risk and this risk should not be minimized as serious complications can occur.
Dr. Moy gave a concise review on the articles by Peralta et al. and Arzola et al. The bedside ultrasonography is definitely another useful tool for us. In this study, it was used to assess gastric contents during the perioperative period. The aim of the study was to describe the qualitative and quantitative ultrasound assessment of the gastric antrum in fasting pregnant women at term. NPO guidelines are followed that recommend similar preoperative fasting intervals for elective c-section and elective surgery. In our L&D we now give patients clear liquids in labor and up to 3 hr prior to c-section. Further research is needed to investigate the feasibility of a predictive model estimating gastric volumes based on the antrum cross sectional area and also patient variables in pregnant women. The article on BMI and incidence of PDPH in parturients showed a decreased PDPH incidence after dural puncture in parturients with increased BMI even after controlling for pushing in labor. HA and the need for an EBP was similar in low and high BMI groups. Unintentional dural puncture occurs in 1% of epidural catheters placed with normal body habitus but can be as high as 4% in morbidly obese parturients. The article surmised that there are possible alterations in the epidural/intrathecal spaces in an obese parturient that may account for the lower incidence of PDPH. Increased epidural pressure may decrease the pressure gradient from intrathecal to epidural space resulting in less CSF leak and a lower incidence of PDPH.
02-04-16 Obstructive Sleep Apnea
Drs. Praslick, Licata, Richman
Liao P et al. Perioperative auto-titrated continuous positive airway pressure treatment in surgical patients with obstructive sleep apnea: a randomized controlled trial. Anesthesiology. 2013 Oct;119(4):837-47 [PubMed]
Chung F et al. Postoperative changes in sleep-disordered breathing and sleep architecture in patients with obstructive sleep apnea. Anesthesiology. 2014 Feb;120(2):287-98 [PubMed]
Oto J et al. Continuous positive airway pressure and ventilation are more effective with a nasal mask than a full face mask in unconscious subjects: a randomized controlled trial. Crit Care. 2013 Dec 23;17(6) [PubMed]
Dr. Praslick summarized all the pertinent information regarding sleep apnea. He gave us a concise review of the Chung et al. article. In this prospective cohort study, both non-obstructive and obstructive sleep apnea patients suffered sleep disturbances particularly on postoperative night 1 and significantly increased frequencies of sleep disordered breathing on postoperative night 3. OSA patients had a significant decrease in sleep efficiency, REM /"dream" sleep and slow-wave sleep on postoperative night 1 and gradually recovered. Non OSA patients followed a similar pattern but to lesser extent. The primary outcomes were polysomnography parameters measuring sleep-disordered breathing. The secondary outcomes were polysomnography parameters measuring sleep architecture. Change in sleep architecture may have contributed to the finding that the most significant exacerbation of sleep breathing disorders occurred on postoperative night 3. Hypopnea was significantly increased after surgery. Apnea hypopnea index (AHI) and oxygen desaturation peaked on postoperative night 3. In the study, REM sleep did not fully recover to preoperative level by postoperative night 7. There were limitations to the study: It did not control for the type of surgery, perioperative medications such as opioids and oxygen tx. Another limitation was that the sleep study was employed a portable level 2 device that was not able to analyze REM density. Dr Praslick contrasted the the definition for monitor levels. A level 1 sleep monitor is used in a sleep lab and gives full polysomnography. A level 2 monitor is used for a home sleep test and allows for sleep staging. In addition for this study sleep monitoring only occurred at night so diurnal changes of the sleep-wake activity would not be detected. Also there could be selection bias of only OSA-related sx patients giving consent more easily and patient wearing CPAP were excluded. Dr Praslick's overview and discussion of OSA "the silent disease" kept everyone's attention.
Dr. Licata gave a complete review of the Liao et al article. This was a randomized, open labeled clinical trial. In this study of 177 OSA patients, auto-titrated continuous positive airway pressure reduced the apnea hypopnea index. Despite this, only 26-48% of the patients used CPAP more than 4 hours per night during perioperative nights. Due to patients dropping out from the study 106 had polysomnography on postop night 3 and 100 completed followup for postop nights 1-5. The reasons for noncompliance were postop generalized discomfort, nausea,and vomiting and this mirrored general public reasons for CPAP not used. We discussed the implications of the increased AHI on night 3 and how this might result in an increased MI risk also found on postop day 3. Some strategies for treatment were discussed such as sleeping in a recliner, better sleep hygiene, use of a single pillow to get optimal positioning, sleeping on the side vs back and having someone to observe the patient at home. There is currently no way to monitor patients postoperatively at home. We might envision an at-home pulseox /apnea monitor with an alert to a central place of monitoring in the future.
The STOPBANG criteria was reviewed. Do you SNORE loudly (louder than talking or loud enough to be heard through closed doors)? Do you often feel TIRED, fatigued, or sleepy during daytime? Has anyone OBSERVED you stop breathing during your sleep? Do you have or are you being treated for high blood PRESSURE? BMI more than 35kg/m2? AGE over 50 years old? NECK circumference > 16 inches (40cm)? GENDER: Male? Our POS uses a STOPBAG version. 2 of 4 + on the STOP has a risk for OSA. 3 of 8 shows increased sensitivity and specificity of the study.
It was mentioned that CPAP use prior to surgery had improved outcomes. If it is used 2-3 night prior to surgery then there was decreased airway edema and decreased obstruction. If used 2-5 nights prior then decreased sleepiness and less mvas. This trial showed potential use for perioperative APAP for the surgical patients with untreated OSA.
Dr. Richman mentioned an additional relevant article: Gali B et al Anesthesiology 2009 110(4) 869-877 [PubMed]. The study looked at OSA risk and PACU behavior risk and put the two together to better identify very high risk patients. A Pre-op screen or diagnosis PLUS a post-op screen for hypopnea/bradypnea, O2 desaturations, apnean and pain-sedation mismatch (appears very sedated, but complains of significant pain). They concluded "Combination of an obstructive sleep apnea screening tool preoperatively (SACS) and recurrent PACU respiratory events was associated with a higher oxygen desaturation index and postoperative respiratory complications. A two-phase process to identify patients at higher risk for perioperative respiratory desaturations and complications may be useful to stratify and manage surgical patients postoperatively”
03-10-16 Nerve Blocks
Drs. Wloch, Fradlis and Kogan
Phyathai, Ronkonkoma 6:00 PM
Machi, et al. Discharge Readiness after Tricompartment Knee Arthroplasty: Adductor Canal versus Femoral Continuous Nerve Blocks-A Dual-center, Randomized Trial. Anesthesiology. 2015 Aug;123(2):444 [PubMed]
Abdallah, et al IV and Perineural Dexmedetomidine Similarly Prolong the Duration of Analgesia after Interscalene Brachial Plexus Block: A Randomized, Three-arm, Triple-masked, Placebo-controlled Trial. Anesthesiology. 2015 Dec 9. [Epub ahead of print] [PubMed]
Dr. Fradlis gave an excellent review of the Abdallah et al. article. There were 99 patients In this study. Patients received either ISB using 15ml ropivicaine 0.5% with 0.5 microgram/kg dexmedetomidine perineurally, dexmedetomidine IV or none (placebo). Dexmedetomidine is an alpha-2 adrenoceptor agonist associated with prolonged analgesia after administration of local anesthesia in a variety of routes-neuraxial, perineural, intraarticular and possibly IV. In this study, both perineural and IV dexmedetomidine prolonged ISB analgesic duration and reduced opioid consumption without prolonging motor blockade. Some limitations to the study were that the dose of dexmedetomidine was based on the researcher's anecdotal experience. In addition, patients were discharged within 3 hrs of surgery to home meaning that sensory and motor tests could not be checked after that time. Our discussion revealed that the study was not sufficiently powered to detect statistically significant differences in the 2 routes of dexmedetomidine. They found that adding dexmedetomidine to single injection ISB with long acting local anesthetic perineural or IV is as effective in prolonging duration of analgesia without prolonging the duration of motor blockade. An additional article "Dexmedetomidine added to ropivicaine extends the duration of interscalene brachial plexus blocks for elective shoulder surgery when compared with ropivicaine alone: A single -center prospective , triple blind, randomized controlled trial" by Fritsch, et al. was also discussed by Dr. Fradlis. It was discussed that dexmedetomidine is not approved by the FDA in the USA for perineural use. It was noted that there is better patient satisfaction with propofol IV compared to dexmedetomidine.
Dr. Kogan gave an excellent review of the Machi, et al. paper. Tricompartment Knee Arthroplasty results in significant moderate to severe postop pain. Continuous femoral nerve blocks provide effective postop analgesia but results in quadriceps weakness and a possible increase in falls. Adductor canal block is a newer alternative. The study found that the continuous adductor canal block did not decrease the time to overall discharge readiness in comparison to continuous femoral nerve block (though it did decrease the time to adequate mobilization since both groups required IV opiates beyond the time to mobilization.) Some limitations are that both treatment groups received introperative joint infiltration with ropivicaine, ketorolac, epinephrine, and traexamic acid. The results may have been different if there was no infiltration. The study was not blinded: the surgeons injected local anesthetic and both physicians and patients knew which block was done. This is not something that we see done at SB clinically. Interestingly, both of these articles reported excellent results but in clinical practice it is seen that this might not be the best effective treatment.
05-05-16 Perioperative Management of Anti-Platelet Therapy
Drs. Kagan, Patel and Zabirowicz.
Eisenberg et al. Safety of short-term discontinuation of antiplatelet therapy in patients with drug-eluting stents. Circulation. 2009 Mar 31;119(12):1634-42. [PubMed]
Biondi-Zoccai et al. A systematic review and meta-analysis on the hazards of discontinuing or not adhering to aspirin among 50,279 patients at risk for coronary artery disease. Eur Heart J. 2006 Nov;27(22):2667-74. [PubMed]
Dr. Patel gave an excellent review of the Eisenberg et al. paper. Discontinuing antiplatelet meds, thienopyridine and acetlysalicylic acid, is a risk factor for late stent thrombosis and very late stent thrombosis. Treatment guidelines recommend antiplatelet therapy for up to 12 months so that endothelialization of the stent can take place. If the patient requires surgery during this period, the question is whether antiplatelet therapy should be discontinued to avoid the risk of bleeding problems. In this modified case-only design study, restricted to Academic Research Consortium-defined definite cases, 161 cases of late stent thrombosis or very late stent thrombosis from 84 articles were reviewed. This type of study was done because these events are so rare. In 19 of the cases, patients received dual antiplatelet therapy at the time of the event. For patients who stopped both antiplatelet meds, the median time to event was 7 days. For patients who stopped thienopyridine and then stopped acetlysalicylic acid, the median time to event was 7 days. For patients who stopped thienopyridine but continued acetlysalicylic acid, the median time to event was 122 days. The study concluded that if acetlysalicylic acid therapy is continued and thienopyridine is stopped short term, then this would be relatively safe in patients with DES.
Dr. Patel reviewed Drug-Eluting Stents and the two types of coating used, paclitaxel and polyne. He also noted that not all stents are the same. Stents in the left main have a greater risk. Bleeding risk is also important and varies by type of surgery. The clinical practice at SB is to give 325 mg chewable acetlysalicylic acid in preop holding because this will be helpful to prevent MI postop when patients leave the hospital.
Dr. Kagan gave a concise review of the Biondi-Zoccai et al. paper. Coronary artery disease. (CAD) was discussed as the leading cause of morbidity and mortality worldwide. Acetlysalicylic acid (ASA) is the most commonly given antiplatelet medication worldwide. Adverse side effects of ASA were reviewed. In addition, certain cases prone to increased bleeding were discussed. This review was done to increase awareness of the hazard of asa withdrawal or noncompliance in patients with CAD or at risk for CAD. They concluded that ASA discontinuation should be advised only when the risk of bleeding or other adverse effects overwhelm that of the CV atherothrombotic events. In our discussion, it was noted that the continuation of ASA does not dictate our type of anesthetic. However, the continuation of plavix becomes an issue with regional anesthesia. It was also noted that the new 2016 guidelines take into account the Poise 2 study and actually advocate continuation of ASA.
Dr. Bennett-Guerrero suggested some additional articles on the subject. Gilard et al 2015, Omar et al 2014 and Feres et al 2013.