Lois A. Connolly

Rapid Sequence Induction and Intubation: Current Controversy

The changing opinion regarding some of the traditional components of rapid sequence induction and intubation (RSII) creates wide practice variations that impede attempts to establish a standard RSII protocol. There is controversy regarding the choice of induction drug, the dose, and the method of administration. Whereas some prefer the traditional rapid injection of a predetermined dose, others use the titration to loss of consciousness technique. The timing of neuromuscular blocking drug (NMBD) administration is different in both techniques. Whereas the NMBD should immediately follow the induction drug in the traditional technique, it is only given after establishing loss of consciousness in the titration technique. The optimal dose of succinylcholine is controversial with advocates and opponents for both higher and lower doses than the currently recommended 1.0 to 1.5 mg/kg dose. Defasciculation before succinylcholine was traditionally recommended in RSII but is currently controversial. Although the priming technique was advocated to accelerate onset of nondepolarizing NMBDs, its use has decreased because of potential complications and the introduction of rocuronium. Avoidance of manual ventilation before tracheal intubation was traditionally recommended to avoid gastric insufflation, but its use is currently acceptable and even recommended by some to avoid hypoxemia and to “test” the ability to mask ventilate. Cricoid pressure remains the most heated controversy; some believe in its effectiveness in preventing pulmonary aspiration, whereas others believe it should be abandoned because of the lack of scientific evidence of benefit and possible complications. There is still controversy regarding the best position and whether the head-up, head-down, or supine position is the safest during induction of anesthesia in full-stomach patients. These controversial components need to be discussed, studied, and resolved before establishing a standard RSII protocol.

Anesthetic management of obstructive sleep apnea patients.

Presented in an illustrative case report and a review of the anesthetic management of obstructive sleep apnea patients. Preoperative evaluation should include a thorough airway evaluation and a comprehensive cardiovascular and pulmonary evaluation. With polysomnography, identification of the severity of sleep apnea can be idenified. Although sleep centers vary in their definitions, severe obstructive sleep apnea is diagnosed if the patient demonstrates an apnea index greater than 70 and an oxygen (O2) desaturation less than 80% with cardiovascular sequelae. Severe sleep apnea patients are at extreme risk for general anesthesia. These risks should be discussed preoperatively with the patient. Unsupervised preoperative sedation should be avoided because of the extreme sensitivity of these patients to sedatives and airway obstruction. Intraoperative management of the obstructive sleep apnea patient varies depending on the severity of the sleep apnea. Invasive monitoring may be necessary if the patient demonstrates evidence of cardiopulmonary dysfunction. With the assistance of the otolaryngologist, the anesthesiologist can formulate an approach to establishing an airway. Intraoperative opioids and sedatives should be limited. The recovery of the sleep apnea patient is extremely important and is the time when most airway emergencies occur. Extubation of the patient should occur when appropriate surgical personnel and equipment are available in case of an airway emergency. Steroids may be used to decrease the amount of airway swelling. Supplemental O2 should be used in patients who demonstrate desaturation. Opioids and sedatives should be avoided, as should other drugs that have central and sedating effects. Postoperative pain is effectively controlled with acetaminophen and topical anesthetic sprays. Postoperative monitoring for apnea, desaturation, and dysrhythmias is a necessity in sleep apnea patients.

Inhalation Anesthesiology and Volatile Liquid Anesthetics: Focus on Isoflurane, Desflurane, and Sevoflurane

Clinical pharmacists rarely are involved in the selection and dosing of anesthetic agents. However, when practicing evidence‐based medicine in a cost‐conscious health care system, optimizing drug therapy is imperative in all areas. Thus, we provide general information on anesthesiology, including the different types of breathing systems and the components of anesthesia machines. Modern inhalation anesthetics that are predominantly used in clinical practice include one gas—nitrous oxide—and new volatile liquid agents—isoflurane, desflurane, and sevoflurane. Desflurane and sevoflurane are the low‐soluble inhalation anesthetics, and they offer some clinical advantages over isoflurane, such as fast induction and faster recovery with long procedures. However, efficient use of isoflurane can match the speed of induction and recovery of the other agents in certain cases. In addition, the patient characteristics, duration and type of procedure, type of breathing system, and efficiency in monitoring must be considered when selecting the most optimal therapy for each patient. Maximizing the clinical advantages of these agents while minimizing the waste of an institutions operating room and pharmacy budget requires an understanding of the characteristics, pharmacokinetics, and pharmacodynamics of these anesthetic agents and the collaborated effort from both the anesthesia and pharmacy departments. An anesthetic agent algorithm is provided as a sample decision‐process tree for selecting among isoflurane, desflurane, and sevoflurane.

Acute smoking increases ST depression in humans during general anesthesia.

UNLABELLED We tested the hypothesis that acute smoking is associated with ST segment depression during general anesthesia in patients without ischemic heart disease. The carbon monoxide (CO) concentration in expired gas and hemodynamic data was measured during general anesthesia for noncardiac or nonperipheral vascular surgery in patients without symptoms or evidence of ischemic heart disease. Increased expired CO concentrations are indicators of recent smoking. Logistic regression analysis identified significant predictors of ST segment depression > or = 1 mm. Both rate pressure product (odds ratio 1.20 for each increase of 1000, 95% confidence interval = 1.04-1.41, P = 0.007) and expired CO concentration (odds ratio 1.05 for each part per million increase, 95% confidence interval = 1.03-1.08, P = 0.001) were significant predictors of ST segment depression when considered simultaneously. Males demonstrated a lower probability of having an episode of ST depression (odds ratio = 0.16, P = 0.01), but this did not change the relationship between rate pressure product and CO as predictors of ST depression. Approximately 25% of chronically smoking patients smoked on the morning of surgery despite instructions not to smoke. IMPLICATIONS Patients under age 65 without symptoms of ischemic heart disease who smoked shortly before surgery had more episodes of rate pressure product-related ST segment depression than nonsmokers, prior smokers, or chronic smokers who did not smoke before surgery. Females were at greater risk of ST depression than males.

Opioid sedation does not alter intracranial pressure in head injured patients

PurposeThis study aimed to examine the effects of sedative doses of morphine, fentanyl and sufentanil on intracranial pressure (ICP) in head-injured patients in whom changes in mean artenal pressure (MAP) were minimized.MethodsFifteen severely head-injured patients (G5C of ≤8) were randomly assigned to receive either fentanyl. sufentanil or morphine, titrating the drug to a maximal 10% decrease in MAP. The patients were subsequently given an infusion of the same opioid. For four hours, ICP MAP and heart rate were recorded. Results: In all groups, there were no increases in ICP. There was a decrease in MAP in the sufentanil group at 10 min (P < 0.05) and 45 min after the initial opioid bolus. These decreases in MAP were not associated with increases in ICP.ConclusionThe study suggests that when opioids are titrated in head-injured patients, worsening intracranial pressure can be avoided.RésuméObjectifÉtudier les effets de doses sédatives de morphine, de fentanyl et de sufentanil sur la pression intracrânienne (PIC) chez des traumatisés du crâne dont la pression artérielle moyenne (RAM) n’avait que légèrement varié.MéthodesQuinze graves traumatisés du crâne (Échelle de Glasgow ≤ 8) ont été assignés aléatoirement pour recevoir du fentanyl, du sufentanil, ou de la morphine titrés de façon à abaisser la PAM de 10% ou moins. Les patients ont par la suite reçu une perfusion du même morphinique. Pendant quatre heures, la PIC, la PAM et la fréquence cardiaque étaient enregistrées.ResultatsLa PIC est demeurée inchangée dans tous les groupes. La PAM a baissé dans le groupe sufentanil à la 10e minute (P > 0,05) et a la 45e minute qui ont suivi l’administration du bolus initial. Ces diminutions de la PAM n’étaient pas associées à une augmentation de la PIC.ConclusionCette étude suggère que l’administration titrée de morphiniques à des traumatisés du crâne ne provoque pas de détérioration de la pression intracrânienne.

Acetazolamide Reduces Referred Postoperative Pain after Laparoscopic Surgery with Carbon Dioxide Insufflation

Background Carbon dioxide is the preferred insufflating gas for laparoscopy because of greater safety in the event of intravenous embolism, but it causes abdominal and referred pain. Acidification of the peritoneum by carbonic acid may be the major cause of pain from carbon dioxide insufflation. Carbonic anhydrase is an enzyme that increases the rate of carbonic acid formation from carbon dioxide. Because acetazolamide inhibits carbonic anhydrase, the authors hypothesized that the pain caused by carbon dioxide insufflation may be decreased by the administration of acetazolamide. Methods A prospective, randomized, double-blind study of 38 patients undergoing laparoscopic surgery during general anesthesia was performed. Acetazolamide (5 mg/kg) or a saline placebo was administered intravenously during surgery. Pain was rated on a visual analog scale (0–10) at four times: when first awake, at discharge from the recovery room, when discharged from the hospital, and on the day after surgery. The site and quality of pain were recorded, as were medications and side effects. Results Initial referred pain scores were lower after acetazolamide (1.00 ± 1.98; n = 18) than after placebo (3.40 ± 3.48; n = 20; P = 0.014), and 78% of patients in the acetazolamide group had no referred pain; however, only 45% patients in the placebo group had no referred pain. Incisional pain scores were not statistically different, and referred pain scores were similar at later times. Conclusions Acetazolamide reduces referred but not incisional pain after laparoscopic surgical procedures. The duration of pain reduction is limited to the immediate postsurgical period.

A Method to Evaluate Upper Airway Mechanics Following Intervention in Snorers

PURPOSE To describe a method that measures multisegment upper airway changes following intervention for snoring and obstructive apnea that controls for physiological fluctuations during sleep. PATIENTS AND METHODS Retropalatal, retroglossal, and retrohyoid airway segments were evaluated before and after application of an oral appliance (OA) in four snoring subjects. Twelve airway segments were evaluated. Physiological fluctuations during sleep were controlled with variably applied nasal continuous positive pressure (CPAP), benzodiazepam-induced sleep, and obtaining measures at zero flow on the first test breath. Airway area was measured endoscopically. RESULTS The methodology identified that following intervention with an OA, maximum retroglossal airway size increased 23.3% +/- 7.5% (P < .05) and retrohyoid size decreased -63.5% +/- 16.0% (P < .05). No changes in retropalatal area (-2.5% +/- 3.0%) or closing pressure were observed. The level of primary obstruction shifted inferiorly in one patient. Airway measures prior to intervention showed small alterations of applied pressure (1 cm H2O) changed retropalatal and retroglossal area an average of 10% +/- 0.9%/cm H2O. CONCLUSION The mechanical effects of limited airway intervention can be measured with a hypotonic, pressure-controlled methodology. At small airway areas, the airway is highly collapsible and airway size fluctuates. Small changes in applied or physiological forces may alter the airway as significantly as the effects of the intervention being evaluated. The hypotonic upper airway method provides a method to control airway collapse and evaluate interventions, such as OA or surgery, for snoring and obstructive sleep apnea syndrome.

Twelve hour anaesthesia in a patient with epidermolysis bullosa

Epidermolysis bulbsa (EB), an inherited disorder presents clinically with recurrent cutaneous blister formation with possible involvement of mucous membranes and other organs. The sequelae of this disease pose multiple challenges to the anaesthetist and operating mom team. Recent literature describes several anaesthetic techniques for the short surgical procedures this patient population may undergo. We describe the anaesthetic technique employed in a 28-yr-old woman with recessive dystrophic epidermolysis hullosa who underwent 12 hr reconstructive surgery followed by a review of the literature that includes a recent description of the possible association of EB with at least two distinct neuromuscular diseases. A detailed description of airway and skin management is described in addition to preoperative concerns. We conclude that a prolonged operative procedure can be undertaken successfully in this population with minimal sequelae involving skin integrity and airway management.RésuméL’épidermolyse huileuse (EB) est une affection héréditaire caratérisée par la formation de phlyctènes avec la possibilité d’une atteinte des muqueuses et d’autres tissus. Les séquelles de cette maladie présentent à l’anesthésiste et à l’équipe chirurgicale plusieurs défis. La littérature récente décrit plusieurs techniques anesthésiques pour les interventions de courte durée que doivent subir ces malades. Nous décrivons ici la technique anesthésique utilisée auprès d’une femme de 28 ans affligée d’épidermolyse bulleuse dystrophique soumise à une chirurgie de reconstruction. Nous poursuivons avec un survol de la littérature dont celle qui établit un lien possible de l’EB avec au moins deux maladies neuromusculaires distinctes. La gestion des voies aériennes et de la peau, et les préoccupations peropératoires sont décrites avec précision. Nous concluons qu’une intervention de longue durée peut être réalisée avec succès et ne comporter que des séquelles minimes pour la peau et les voies aériennes.

Outcome analysis of continuous intraoperative renal replacement therapy in the highest acuity liver transplant recipients: A single-center experience

Background. Orthotopic liver transplantation is the definitive treatment modality for patients with end‐stage liver disease. Pre–orthotopic liver transplantation renal dysfunction has a significant negative influence on outcomes post–orthotopic liver transplantation. Intraoperative renal replacement therapy is an adjunctive therapy to address the metabolic challenges during orthotopic liver transplantation in patients with a high acuity of illness. The impact of intraoperative renal replacement therapy on post–orthotopic liver transplantation outcomes, however, is unclear. Methods. From October of 2012 to April of 2016, 96 adult patients underwent orthotopic liver transplantation for end‐stage liver disease. Three groups were identified: (1) Group I: patients with pre–orthotopic liver transplantation renal dysfunction who underwent intraoperative renal replacement therapy, (2) Group II: patients with pre–orthotopic liver transplantation renal dysfunction who did not receive intraoperative renal replacement therapy, and (3) Group III: patients with orthotopic liver transplantation without evidence of pretransplant renal dysfunction. Results. At 17.7 months follow‐up, there was no difference in survival among the study groups. Physiologic model for end‐stage liver disease at the time of orthotopic liver transplantation was significantly higher in both groups with renal dysfunction (I = 43, II = 39) than in Group III (18). Post–orthotopic liver transplantation, 12‐month patient survival in Group II was 100%. While the model for end‐stage liver disease score at orthotopic liver transplantation was significantly different between Group I and Group III, the 12‐month, post–orthotopic liver transplantation patient survival was comparable at 78% vs 88%, respectively. Conclusion. Intraoperative renal replacement therapy is a safe adjunctive therapy during liver transplantation of critically ill patients with renal dysfunction. Identifying patients who require intraoperative renal replacement therapy would improve intraoperative and post–liver transplant survival and may facilitate recovery of native kidney function after transplant.

Body mass index: an illogical correlate of obesity.

To the Editor:—Kudos to Waisel et al. for his recent contribution to our journal, “Anesthesiology Trainees Face Ethical, Practical and Relational Challenges in Obtaining Informed Consent.” And also to our editors, for highlighting the usefulness of nonbiomedical research paradigms. Waisel et al. used narrative analysis, one genre of qualitative research methods, to deepen our understanding of the theory that underlies obtain informed consent in the practice of anesthesiology. Narrative analysis is only one of many accepted methodologies included in the realm of qualitative research. Others include biographical methods, critical theory development, hermeneutics, action research, and historiography. Qualitative methods, in any form, are both similar and different from our more familiar, quantitative, statistically based methods. In both quantitative and qualitative methods there is an initially defined research question; optimal data sampling is based on known population characteristics; data collection and analysis follows rigorously defined protocols; and all sampling, data collection, analysis, and dissemination are in compliance with accepted research ethics. However, unlike hypothesis testing and statistical methods, qualitative research employs an inductive approach; the aim of qualitative research is to generate a theory grounded in both confirming and disconfirming evidence, such as observation, interviews, and documentation. These methods for theory generation are more useful in situations of complex social interactions where reductionist, statistical methods cannot adequately encapsulate all social confounds into one testable hypothetical premise, to the exclusion of all others. Qualitative research methods have been a mainstay of social science and educational and psychological research for close to a century. And within the past two decades, they have been successfully merged with quantitative methods, especially in educational research, to both generate and confirm theory. This innovative methodology is termed “mixed methods research.” For those more interested in understanding and using complimentary qualitative methods, several outstanding and readily accessible reference texts are available. In addition, both PubMed and the Education Resources Information Center have medical subject headings that allow the reader to identify literature that employs qualitative methods. Hopefully the paradigm wars are indeed over, and the era of paradigm cooperation has begun in anesthesiology as well.