Gary Loyd

Anesthetic requirement is increased in redheads

Background:Age and body temperature alter inhalational anesthetic requirement; however, no human genotype is associated with inhalational anesthetic requirement. There is an anecdotal impression that anesthetic requirement is increased in redheads. Furthermore, red hair results from distinct mutations of the melanocortin-1 receptor. Therefore, the authors tested the hypothesis that the requirement for the volatile anesthetic desflurane is greater in natural redheaded than in dark-haired women. Methods:The authors studied healthy women with bright red (n = 10) or dark (n = 10) hair. Blood was sampled for subsequent analyses of melanocortin-1 receptor alleles. Anesthesia was induced with sevoflurane and maintained with desflurane randomly set at an end-tidal concentration between 5.5 and 7.5%. After an equilibration period, a noxious electrical stimulation (100 Hz, 70 mA) was transmitted through bilateral intradermal needles. If the volunteer moved in response to stimulation, desflurane was increased by 0.5%; otherwise, it was decreased by 0.5%. This was continued until volunteers “crossed over” from movement to nonmovement (or vice versa) four times. Individual logistic regression curves were used to determine desflurane requirement (P50). Desflurane requirements in the two groups were compared using Mann–Whitney nonparametric two-sample test; P < 0.05 was considered statistically significant. Results:The desflurane requirement in redheads (6.2 vol% [95% CI, 5.9–6.5]) was significantly greater than in dark-haired women (5.2 vol% [4.9–5.5]; P = 0.0004). Nine of 10 redheads were either homozygous or compound heterozygotes for mutations on the melanocortin-1 receptor gene. Conclusions:Red hair seems to be a distinct phenotype linked to anesthetic requirement in humans that can also be traced to a specific genotype.

Patient state index : titration of delivery and recovery from propofol, alfentanil, and nitrous oxide anesthesia

Background The Patient State Index (PSI) uses derived quantitative electroencephalogram features in a multivariate algorithm that varies as a function of hypnotic state. Data are recorded from two anterior, one midline central, and one midline posterior scalp locations. PSI has been demonstrated to have a significant relation to level of hypnosis during intravenous propofol, inhalation, and nitrous oxide–narcotic anesthesia. This multisite study evaluated the utility of PSI monitoring as an adjunct to standard anesthetic practice for guiding the delivery of propofol and alfentanil to accelerate emergence from anesthesia. Methods Three hundred six patients were enrolled in this multicenter prospective randomized clinical study. Using continuous monitoring throughout the period of propofol–alfentanil–nitrous oxide anesthesia delivery, PSI guidance was compared with use of standard practice guidelines (both before [historic controls] and after exposure to the PSA 4000 monitor [Physiometrix, Inc., N. Billerica, MA; standard practice controls]). Anesthesia was always administered with the aim of providing hemodynamic stability, with rapid recovery. Results No significant differences were found for demographic variables or for site. The PSI group received significantly less propofol than the standard practice control group (11.9 &mgr;g · kg−1 · min−1;P < 0.01) and historic control group (18.2 &mgr;g · kg−1 · min−1;P < 0.001). Verbal response time, emergence time, extubation time, and eligibility for operating room discharge time were all significantly shorter for the PSI group compared with the historic control (3.3–3.8 min;P < 0.001) and standard practice control (1.4–1.5 min;P < 0.05 or P < 0.01) groups. No significant differences in the number of unwanted somatic events or hemodynamic instability and no incidences of reported awareness were found. Conclusions Patient State Index–directed titration of propofol delivery resulted in faster emergence and recovery from propofol–alfentanil–nitrous oxide anesthesia, with modest decrease in the amount of propofol delivered, without increasing the number of unwanted events.

The influence of epidural analgesia on cesarean delivery rates: A randomized, prospective clinical trial

OBJECTIVE The effects of epidural analgesia on the progress of labor are controversial. The objective of this study was to determine the effect of epidural analgesia on cesarean delivery rates in a population of patients randomly assigned to receive either epidural analgesia or intravenous opioids for intrapartum pain relief. STUDY DESIGN From January 1995 to May 1996, 318 spontaneously laboring, term, nulliparous patients were randomly assigned to receive either intravenous opioids or epidural analgesia for pain relief. Labor was managed according to the principles of active management of labor. Cesarean delivery was performed for obstetric indications. Data analysis was conducted on an intent-to-treat basis. A subanalysis was subsequently performed on patients who were compliant with the allocated form of treatment. RESULTS One hundred sixty-two patients were randomly assigned to receive intravenous meperidine and 156 were randomly assigned to receive epidural analgesia. Maternal age, gravidity, race, gestational age, and cervical dilatation at admission and at first analgesic dose did not differ between the groups. Intent-to-treat data analysis revealed no significant difference in the cesarean delivery rate between the 2 groups, being 13.6% in the opioid group and 9.6% in the epidural group (relative risk 0.70, 95% confidence interval 0.38-1.31, P >.05). Cesarean delivery rates for the indication of dystocia also did not differ, being 10.5% in the opioid group and 5.8% in the epidural group (relative risk 0.56, 95% confidence interval 0.26-1.21, P >.05). Subanalysis of the data from patients who were compliant with the allocated form of treatment revealed that patients in the epidural group (n = 147) were 3 times more likely to have an active phase duration >/=8 hours and were 10 times more likely to require >/=2 hours in the second stage of labor than were those in the opioid group (n = 78). There were no significant differences in cesarean delivery rates in this subanalysis, being 7.7% in the opioid group and 8.8% in the epidural group (relative risk 1.15, 95% confidence interval 0.45-2.91, P >. 05). The cesarean delivery rates for dystocia were also similar in the subanalysis, being 3.8% in the opioid group and 5.5% in the epidural group (relative risk 1.42, 95% confidence interval 0.39-5. 22, P >.05). CONCLUSION Epidural analgesia provides safe and effective intrapartum pain control and may be administered without undesirable effects on labor outcome.

An Atypical Case of Reverse Takotsubo Cardiomyopathy During General Anesthesia in a 30-Year-Old Male With Post-Traumatic Stress Disorder

AKOTSUBO CARDIOMYOPATHY, also referred to as transient left ventricular ballooning syndrome or stressinduced cardiomyopathy, describes a rapid-onset, yet reversible systolic dysfunction that typically is triggered by an acute, stressful event. The pathophysiology is not completely understood, and similar presentations have been described as a result of the endocrine crisis of pheochromocytoma, 1 subarachnoid hemorrhage, 2 and Guillain-Barre syndrome. 3 A wide heterogeneity of presentation suggests that multiple overlapping mechanisms such as neurogenic catecholamine-induced myocardial stunning, 4 microvascular dysfunction, 5 and multivessel epicardial spasm 6,7 may play a role. Symptoms mimic an ST-segment elevation myocardial infarction. Patients present with ischemic electrocardiographic changes, reduced left ventricular ejection fraction, and a balloon-like contractility pattern that portrays a unique wall-motion abnormality that extends beyond the myocardial territory of a single coronary artery. The classic form presents as transient apical ballooning with basal hypercontractility. In more rare cases of reverse Takotsubo, the opposite is observed—transient dilatation of the basal segments of the heart with hyperkinesis of the apex. It has been estimated that 0.5% to 2% of patients with symptoms of an acute coronary syndrome may have Takotsubo cardiomyopathy. 7,8 Of these, 95% are postmenopausal women with a median age of 63 years. 4 For the first time, the authors present a case of anesthesia-induced reverse Takotsubo cardiomyopathy in a young, healthy male with a history of posttraumatic stress disorder (PTSD). In this atypical patient, anesthesia, perioperative stressors, and chronic psychologic distress may have triggered transient left ventricular ballooning.

Mood during Epidural Patient-controlled Analgesia with Morphine or Fentanyl

Background Mood states during epidural opioids are not known. The authors studied the change in mood during the 48‐h period of epidural morphine and epidural fentanyl in 47 patients after elective hip or knee joint arthroplasty. Methods An epidural catheter was inserted at the L2‐L3 or L3‐L4 interspace. Anesthesia was induced with thiopenthal and maintained with isoflurane and nitrous oxide. One hour before the conclusion of the operation, patients received an epidural bolus injection of 2 mg morphine (n = 23) or 100 micro gram fentanyl (n = 24), followed by the same opiate (125 micro gram/ml morphine or 25 micro gram/ml fentanyl) epidurally delivered by a patient‐controlled analgesia (PCA) pump in the postoperative period for 48 h. Mood was assessed using the bipolar form of the Profile of Mood States before operation and 24 h, 48 h, and 72 h after operation. Results There was no significant difference in pain intensity between the groups during epidural PCA. Mood states became more positive over time in the patients who received morphine (P < 0.01 at 48 h) and negative in those who were given fentanyl (P < 0.01 at 24 and 48 h, respectively) compared with those before the operation, and they were more positive in the morphine than in the fentanyl group at 24 h, 48 h (P < 0.05), and 72 h (P < 0.01). Patients in the morphine group were more composed, agreeable, elated, confident, energetic, and clearheaded than were those in the fentanyl group (P < 0.05). There was no correlation between mood scores and pain scores in either group. There was an inverse correlation at 48 h between mood scores and plasma fentanyl concentrations (r = ‐0.58, P < 0.05). Conclusion Mood states are significantly more positive during epidural morphine PCA than they are during epidural fentanyl PCA.

A course for anaesthesiology residents using simulation

tallies the number of times each application is opened and the number of minutes the application remains open. We tracked student use of the PDAs for 3 months (September–November) and collected data in 3 ways, through focus groups, student survey and AppUsage. Evaluation of results and impact Our data indicate that students felt that the PDAs were useful during their clinical rotations. A total of 115 students completed the survey and rated the usefulness of the clinical applications using a scale of 1)5, where 1 1⁄4 not useful and 5 1⁄4 extremely useful. The 2 applications that received an average rating above 4 (ePocrates Rx, Version 4.88, and 5mCC, Version 4.32) were also listed most frequently as the students’ ‘favourite clinical applications’. AppUsage data indicated that student usage of the clinical applications in terms of number of launches per week increased from an average of 28.86 launches ⁄week in September to an average of 36.99 launches ⁄week in November; however, the use of the clinical applications in terms of total number of minutes per week decreased from an average of 36.45 minutes ⁄week in September to an average of 28.36 minutes ⁄week in November. We speculated that the decrease in total usage time may have been caused by increased student skill or comfort levels with the PDA, which, in turn, increased student efficiency when using an application. Focus group participants also reported that the PDA made them more efficient by enabling them to manage patients and access information more quickly. (They also liked having fewer books to carry!) The students’ positive feedback, in part, contributed to our decision to expand the PDA programme to include all students; we continue to study its impact, particularly during the basic science years. Our experiences with the PDA project also confirmed that any enterprisewide technology initiative requires enormous resources in terms of time, expertise and funding.

GlideScope stylet associated with endotracheal tube T-connector split causing a breathing circuit leak

2013;03:74-9. [8] Veselis RA, Reinsel RA, Wronski M, Marino P, Tong WP, Bedford RF. EEG and memory effects of low-dose infusions of propofol. Br J Anaesth 1992;69:246-54. [9] Goudra BG, Penugonda LC, Sinha AC. Intra-lingual succinylcholine for the treatment of adult laryngospasm in the absence of IV access. J Anaesthesiol Clin Pharmacol 2013;29:426-7. [10] LiuH,WaxmanDA,Main R,Mattke S.Utilization of anesthesia services during outpatient endoscopies and colonoscopies and associated spending in 2003–2009. JAMA 2012;307:1178-84.