Vincent J. Kopp

Tracheal extubation of deeply anesthetized pediatric patients: a comparison of desflurane and sevoflurane.

In this study, we examined the emergence characteristics of children tracheally extubated while deeply anesthetized with desflurane (Group D) or sevoflurane (Group S). Forty-eight children were randomly assigned to one of the two groups. At the end of the operation, all subjects were tracheally extubated while breathing 1.5 times the minimal effective concentration of assigned inhaled anesthetic. Recovery characteristics and complications were noted. Group D patients had higher arousal scores on arrival to the postanesthesia care unit than Group S patients. Later arousal scores were not significantly different. No serious complications occurred in either group. Coughing episodes and the overall incidence of complications after extubation were more frequent in Group D. Readiness for discharge and actual time to discharge were not significantly different between groups. Emergence agitation was common in both groups (33% overall, 46% for Group D, and 21% for Group S). Narcotic administration in the postanesthesia care unit occurred more frequently in Group D (10 of 24 patients) versus Group S (3 of 24 patients). Premedication with oral midazolam resulted in significantly longer emergence times regardless of the potent inhaled anesthetic administered.

Anesthesiologists and perioperative communication

LOOK up communication in a major anesthesiology text, a medical dictionary, or reference book on legal issues and you will not find the word listed, except in the most qualified sense. Yet read these books and you find ample evidence of the importance of communication in anesthesia practice. The word derives from the Latin communicare, meaning to impart, participate. Anesthesiologists, other health professionals, and patients communicate on multiple levels every day. Anesthesiologists participate in activities involving complex social transactions with medical, legal, ethical, and personal significance. They also impart and receive information that affects their participation in other medical professionals’ actions. The quality and quantity of anesthesiologists’ communications has a bearing on the values, outcomes, and standards of their professional work. Recognizing the importance of communication, the American Society of Anesthesiologists has charged the Committee on Communication to “improve public education as it relates to anesthesiology.”‡ Good communication is as important to protecting professional integrity as it is to patient safety and satisfaction. For these reasons, it is as important for anesthesiologists to pay attention to the structure and function of professional communication as it is to learn the pharmacokinetics and pharmacodynamics of drugs.

Multimodal Protocol Reduces Postoperative Nausea and Vomiting in Patients Undergoing Le Fort I Osteotomy

PURPOSE To assess the impact of a multimodal antiemetic protocol on postoperative nausea and vomiting (PONV) after Le Fort I osteotomy. MATERIALS AND METHODS Consecutive patients undergoing Le Fort I osteotomy with or without additional procedures at a single academic institution were recruited as the intervention cohort for an institutional review board-approved prospective clinical trial with a retrospective comparison group. The intervention cohort was managed with a multimodal antiemetic protocol, including total intravenous anesthesia; prophylactic ondansetron, steroids, scopolamine, and droperidol; gastric decompression at surgery end; opioid-sparing analgesia; avoidance of morphine and codeine; prokinetic erythromycin; and fluids at a minimum of 25 mL/kg. The comparison group consisted of consecutive patients from a larger study who underwent similar surgical procedures before protocol implementation. Data, including occurrence of PONV, were extracted from medical records. Data were analyzed in bivariate fashion with the Fisher exact and Wilcoxon rank-sum tests. Logistic regression was used to compare the likelihood of nausea and vomiting in the 2 cohorts after controlling for demographic and surgical characteristics. A P value less than .05 was considered significant. RESULTS The intervention (n = 93) and comparison (n = 137) groups were similar in gender (58% and 65% female patients; P = .29), race (72% and 71% Caucasian; P = .85), age (median, 19 and 20 years old; P = .75), proportion of patients with known risk factors for PONV (P = .34), percentage undergoing bimaxillary surgery (60% for the 2 groups), and percentage for whom surgery time was longer than 180 minutes (63% and 59%; P = .51). Prevalence of postoperative nausea was significantly lower in the intervention group than in the comparison group (24% vs 70%; P < .0001). Prevalence of postoperative vomiting was likewise significantly lower in the intervention group (11% vs 28%; P = .0013). The likelihood that patients in the comparison group would develop nausea was 8.9 and that for vomiting was 3.7 times higher than in the intervention group. CONCLUSION This multimodal protocol was associated with substantially decreased prevalence of PONV in patients undergoing Le Fort I osteotomy.

Hyperoxia in Pediatric Anesthesia: Time for Reconsideration?

To the Editor:—Kalkman et al. link anesthesia to clinically deviant behaviors in children anesthetized for urologic procedures before age 2 yr but make no mention of intraoperative oxygen measurement in their study cohort. Wilder et al. link multiple pediatric anesthetic exposures to learning disabilities using a sophisticated database, albeit one built before pulse oximetry was in wide use. Editorially, Patel and Sun provide a review of molecular mechanisms with “relevance” to human development that overlooks the current state of data pertaining to oxygen’s neurotoxic effects in cell and animal models. Although all exemplify Engle’s proposition that scientists and clinicians must account for how submolecular or molecular actions ramify through a “continuum of natural systems” to produce events at higher systems levels—persons, families, communities, cultures, the biosphere—none acknowledge that early and multiple anesthetic exposure is also a marker for early and multiple oxygen exposure. Anesthesiologists and the anesthesia literature, by and large, tend to discount supplemental oxygen effects in patient care in the absence of ischemia–reperfusion injury. Others have more balanced views. Maltepe and Saugstad note that evolution equips humans with numerous hypoxemia defense responses; hyperoxia, however, always iatrogenic, is not as easily defended against, biologically speaking. Neonatologists know hyperoxia is not always beneficial in neonatal resuscitation. Supplemental oxygen use for 3 min or more at birth shows a vexing connection to an increased cancer incidence for children younger than 8 yr. The now well established association of retinopathy of prematurity with supplemental oxygen use was incorrectly overlooked for decades. Degos et al. list hypoxia-induced oxidative stress reduction among potential targets for neuroprotective efforts. But significant hypoxemia may be less common than intentional hyperoxia in pediatric anesthesia practice. Even with the classic 70% nitrous oxide–30% oxygen plus volatile anesthetic inhalational induction sequence, hyperoxia exists. Recent bench research using cell cultures and animal models shows that hyperoxia alters cell ultrastructure and function across multiple organelle and neuronal action sites: mitochondria, membrane surfaces, cell nuclei, and progenitor cell lines. Reactive oxygen species, with other mechanisms, are a source of submolecular injury where hyperoxia is induced experimentally. Such data suggest that neurocidal/neurotoxic potential effects research must account for hyperoxia’s submolecular effects, too— effects Engle’s model predicts will express at higher levels of biopsychosocial organization. Endeavors such as Safety of Key Inhaled and Intravenous Drugs in Pediatrics (SAFEKIDS) and General Anesthesia for Effects on Neurodevelopmental Outcome and Apnea in infants (GAS) are much needed. Should protocols in future clinical studies include control anesthetics administered at atmospheric or “capped” oxygen partial pressures? Controlled for, hyperoxic effects—known and unknown—might be reasonably addressed as answers emerge to the question, Do anesthetics damage the developing human brain? How else can we gain certainty that iatrogenic hyperoxia does not also play a role in the human developmental adverse outcomes we are now tempted to attribute predominantly to anesthetic agents? Sound science dictates that any known factors that might contribute to pediatric behavioral problems, such as lead, iron, and mercury levels—not just anesthetic exposure—should be taken into account. Iatrogenic hyperoxia, sadly, might need to be investigated, too.

Diabetes Insipidus and Epidural Analgesia for Labor

iabetes insipidus (DI) is a complication of pregnancy with an incidence of 2-4 cases per 100,000 pregnancies (1). Patients with DI com- plain of unremitting thirst, a symptom which should raise suspicion of hypovolemia. Peripartum DI can occur in combination with hypertension and abnor- malities in liver and kidney function, making differ- entiation from preeclampsia difficult (2,3). Because urinary output does not decrease with mild hypovo- lemia in patients with DI, dehydration is likely if fluid intake is not adequate. When regional anesthetic tech- niques for labor are used, attention to the potential hazard of hypovolemia is mandatory. Although epi- dural analgesia is used routinely at many centers, it is rare that central venous pressure (CVP) monitoring is required to ensure its safety. This case illustrates the utility of CVP monitoring when noninvasive assess- ment of volume status is difficult. It also shows that thirst does not necessarily imply volume depletion.

Postdischarge Nausea and Vomiting Remains Frequent After Le Fort I Osteotomy Despite Implementation of a Multimodal Antiemetic Protocol Effective in Reducing Postoperative Nausea and Vomiting

PURPOSE To assess the prevalence of postdischarge nausea and vomiting (PDNV) after Le Fort I osteotomy with and without the use of a multimodal antiemetic protocol shown to decrease postoperative nausea and vomiting (PONV). MATERIALS AND METHODS Consecutive patients undergoing Le Fort I osteotomy with or without additional procedures at a single academic institution formed the intervention cohort for an institutional review board-approved prospective clinical trial with a retrospective comparison group. The intervention cohort was managed with a multimodal antiemetic protocol. The comparison group consisted of consecutive patients who underwent similar surgical procedures at the same institution before protocol implementation. All patients were asked to complete a postdischarge diary documenting the occurrence of nausea and vomiting. Those who completed the diaries were included in this analysis. Data were analyzed with the Fisher exact test and the Wilcoxon rank sum test. A P value less than .05 was considered significant. RESULTS Diaries were completed by 85% of patients in the intervention group (79 of 93) and 75% of patients in the comparison group (103 of 137). Patients in the intervention (n = 79) and comparison (n = 103) groups were similar in the proportion of patients with validated risk factors for PDNV, including female gender, history of PONV, age younger than 50 years, opioid use in the postanesthesia care unit (PACU), and nausea in the PACU (P = .37). The prevalence of PDNV was unaffected by the antiemetic protocol. After discharge, nausea was reported by 72% of patients in the intervention group and 60% of patients in the comparison group (P = .13) and vomiting was reported by 22% of patients in the intervention group and 29% of patients in the comparison group (P = .40). CONCLUSION Modalities that successfully address PONV after Le Fort I osteotomy might fail to affect PDNV, which is prevalent in this population. Future investigation will focus on methods to minimize PDNV.

POINT: Does Low-Dose Oxygen Expose Patients With COPD to More Radiation-Like Risks Than Patients Without COPD? Yes.

ABBREVIATIONS: AOT = ambulatory oxygen therapy; BTS Home Oxygen Guidelines = British Thoracic Society Guidelines for Home Oxygen in Adults; CH = chronically hypoxemic; LDO = low-dose oxygen; LDOT = low-dose oxygen therapy; LFOT = low-flow oxygen therapy; LOLA = lowest oxygen level acceptable; LTOT = long-term oxygen therapy; MRC = Medical Research Council; NAC = N-acetyl-cysteine; NC = nasal cannula; NOTT = Nocturnal Oxygen Therapy Trial; OT = oxygen toxicity; ROIH = radiation-oxygen injury homology; RONS = reactive oxygen and nitrogen species; SpO2 = oxygen saturation by pulse oximetry

Does isoflurane or isoflurane plus hyperoxia induce apoptotic cell death

October 2013 • Volume 117 • Number 4 www.anesthesia-analgesia.org 1023 In Response Does Isoflurane or Isoflurane plus Hyperoxia Induce Apoptotic Cell Death? REFERENCES 1. Cho AR, Kwon JY, Kim KH, Lee HJ, Kim HK, Kim ES, Hong JM, Kim C. The effects of anesthetics on chronic pain after breast cancer surgery. Anesth Analg 2013;116:685–93 2. Shin SW, Cho AR, Lee HJ, Kim HJ, Byeon GJ, Yoon JW, Kim KH, Kwon JY. Maintenance anaesthetics during remifentanil-based anaesthesia might affect postoperative pain control after breast cancer surgery. Br J Anaesth 2010;105:661–7 3. Woolf CJ, Salter MW. Neuronal plasticity: increasing the gain in pain. Science 2000;288:1765–9 4. Corris R, Chou J, Riedel B, Collins M. Sevoflurane and its role in the development of chronic postsurgical pain: where is the smoking gun? Anesth Analg 2013;117:1022 5. Guignard B, Bossard AE, Coste C, Sessler DI, Lebrault C, Alfonsi P, Fletcher D, Chauvin M. Acute opioid tolerance: intraoperative remifentanil increases postoperative pain and morphine requirement. Anesthesiology 2000;93:409–17

Rebuttal From Drs Kopp and Stavas

hypoxemic COPD is both safe and effective, and improves survival and pulmonary hemodynamics when used long-term in CH patients with COPD. Indications for treatment in both acutely ill patients with COPD and CH patients with COPD as well as recommendations for achieving a clinically safe, objectively targeted LDO delivery have been reasonably established. Does low-dose oxygen expose patients with COPD to more radiation-like risks than patients without COPD? No. Particularly with regard to CH patients with COPD, it is an increasing challenge from a US regulatory and clinical care perspective to ensure that qualified patients have access to LDO for LTOT. Generating a concern for a theoretical and speculative risk could unintentionally add to the list of impediments to access to evidence-based care.

Might hyperoxia during surgical anaesthesia contribute to older patients' higher dementia risk?

Chen et al [1][1] present data showing that patients aged 50 and over have an earlier onset and higher hazard ratios for dementia following surgery and anaesthesia than controls, irrespective of the type of anaesthesia used - intravenous or intramuscular, regional or general. This finding begs the