Apneic Technique in Laryngotracheal Surgery.

Background Apneic oxygenation can be applied to select laryngotracheal procedures to improve operative visualization and avoid potential complications associated with intubation and jet ventilation.  Aims/objectives The authors sought to determine if apneic oxygenation using a high-flow nasal cannula could be used as a safe alternative airway management strategy for the duration of select laryngotracheal procedures. Methods Single institution, multi-site retrospective review of 38 adult (>18 years old) patients undergoing apneic oxygenation in the setting of various laryngotracheal procedures from January 2017 through January 2018. Humidified oxygen was delivered via a high-flow nasal cannula. The data was collected and analyzed using SAS version 9.4 (SAS Institute, Cary, NC). Results Twenty-four women and 14 men, mean age 60.0 years (SD 16.1; 36-89) and 70.1 years (SD 7.2; 56-81), respectively, underwent a mean total apneic time of 23.9 minutes (13-40). A statistically significant correlation existed between apneic time and minimum oxygen saturation (Pearson correlation coefficient 0.38; p=0.018). Twenty-one patients resumed spontaneous ventilation without the need for jet ventilation, mask ventilation, or placement of a definitive airway during the procedure.  Conclusions and significance Apneic oxygenation allows for extended periods of operating without the need for the placement of an endotracheal tube in patients undergoing general anesthesia for select laryngotracheal procedures.

Postoperative nausea and vomiting after bariatric surgery and dexmedetomidine anesthetic: a propensity-weighted analysis.

BACKGROUND: Patients undergoing laparoscopic bariatric surgery have high rates of postoperative nausea and vomiting (PONV). Dexmedetomidine based anesthetic could reduce PONV rates. OBJECTIVES: To determine if PONV rates differ in patients undergoing laparoscopic bariatric surgery with anesthesia primarily based on dexmedetomidine or standard anesthetic management with inhalational agents and opioids. SETTING: University hospital. METHODS: From January 2014 to April 2018, 487 patients underwent laparoscopic bariatric surgery and met inclusion criteria (dexmedetomidine, n = 174 and standard anesthetic, n = 313 patients). In both groups, patients received preoperative PONV prophylaxis. We analyzed rates of PONV and moderate-to-deep sedation. A propensity score was calculated and outcomes were assessed using generalized estimating equations with inverse probability of treatment weighting. RESULTS: Perioperative opioids and volatile anesthetics were reduced in dexmedetomidine patients. During anesthesia recovery the incidence of PONV was similar between dexmedetomidine and standard anesthetic patients (n = 37 [21.3%] versus n = 61 [19.5%], respectively; inverse probability of treatment weighting odds ratio = 1.35; 95% confidence interval .78-2.32, P = .281), and the incidence of sedation higher in dexmedetomidine patients (n = 86 [49.4%] versus n = 75 [24.0%]; inverse probability of treatment weighting odds ratio = 2.43; 95% confidence interval 1.47-4.03, P < 0.001). Rates of PONV and sedation were similar during the remainder of the hospital stay. A secondary sensitivity analysis was performed limited to dexmedetomidine patients who did not receive volatile and results were similar. CONCLUSIONS: While dexmedetomidine-based anesthesia was associated with reduced opioid and volatile agents use, it was not associated with a reduction of PONV. The higher rates of moderate-to-deep sedation during anesthesia recovery observed with dexmedetomidine may be undesirable in morbidly obese patients.

Effects of propofol on intraoperative parathyroid hormone monitoring in patients with primary hyperparathyroidism undergoing parathyroidectomy: a randomized control trial.

PURPOSE: Serial measurements of parathyroid hormone (PTH) serum concentrations aid parathyroidectomy surgery. There are concerns that propofol may increase PTH concentrations and/or interfere with PTH assays. The primary purpose of this study is to determine the effects of propofol on PTH concentrations in patients with primary hyperparathyroidism and to determine its effect on PTH assays. METHODS: Thirty patients with primary hyperparathyroidism were assigned randomly to induction and maintenance with either propofol or sevoflurane. Blood samples for PTH assays were obtained pre-induction, immediately after induction, ten minutes after induction, and after excision of parathyroid adenoma. The primary endpoint was the PTH concentration at ten minutes after induction. This endpoint was compared between groups using analysis of covariance adjusting for pre-induction PTH. An in vitro study was performed with four different pools of PTH concentrations that were spiked with increasing concentrations of propofol. Serum PTH was measured in duplicate in each sample and analyzed using repeated measures analysis of variance. RESULTS: At ten minutes after induction, PTH concentrations did not differ significantly between groups (least square mean difference -7.0 pg·mL(-1); 95% confidence interval, -34.2 to +20.2). The PTH level in vitro did not change significantly with increasing propofol concentrations. DISCUSSION: Parathyroid hormone concentrations in patients with primary hyperparathyroidism were not affected by the type of anesthesia (propofol vs sevoflurane). Furthermore, propofol was found not to interfere with PTH assays at clinically relevant concentrations. There is no evidence to support the avoidance of a propofol anesthetic for parathyroid surgery.

Fructose-1,6-bisphosphate and fructose-2,6-bisphosphate do not influence brain carbohydrate or high-energy phosphate metabolism in a rat model of forebrain ischemia.

Phosphorylated fructose compounds have been reported to lessen neuronal injury in in vitro models of hypoxia and in vivo models of ischemia. Although a variety of mechanisms have been proposed to account for this finding, it is unknown if intracellular uptake and incorporation of these compounds into the glycolytic pathway contribute to the benefit. We evaluated phosphorylated fructose administration in an adult rat model of transient, near-complete cerebral ischemia to determine its impact on brain metabolism before, during, and after ischemia. Fifty-four pentobarbital anesthetized rats were randomly assigned to receive IV infusions of either fructose-1,6-bisphosphate, fructose-2,6-bisphosphate, or 0.9% saline. After 2 hours of infusion, 18 rats (6/treatment group) were subjected to brain harvesting before any ischemia, 18 additional rats had brain harvesting at the completion of 10 minutes of forebrain ischemia (2-vessel occlusion plus induced hypotension), and 18 rats had harvesting after ischemia and 15 minutes of reperfusion. Cortical brain samples were analyzed for ATP, ADP, AMP, phosphocreatine, glucose, and glycogen. When compared with placebo, neither phosphorylated fructose compound altered preischemic, intraischemic, or postischemic concentrations of brain high-energy phosphates, glucose, glycogen, or lactate, nor did they influence the intraischemic metabolism of endogenous brain glucose or glycogen. On the basis of these results, we conclude that mechanisms other than augmented carbohydrate metabolism are responsible for previous reports of neuronal protection by the bisphosphonates.

Inability to ventilate while using a silicone-based endotracheal tube.

We present a complication associated with herniation of a specially designed silicone-based endotracheal tube (ETT) cuff used for laryngeal nerve monitoring (electromyographic [EMG] ETT). Lung ventilation in our patient was initially unimpeded. However, 30 minutes after initiation of anesthesia with desflurane and nitrous oxide, there was a sudden inability to ventilate due to the herniation of the ETT cuff presumably caused by diffusion of nitrous oxide into the silicone-based cuff. In vitro testing has shown that the increase in intracuff pressure during ventilation with nitrous oxide in the silicone-based EMG ETT is much greater (approximately 50 mmHg) than that in the polyvinyl chloride-based ETT (approximately 10 mmHg) routinely used in our department.

Obesity as a risk factor for unanticipated admissions after ambulatory surgery.

OBJECTIVE: To test the hypothesis that obesity is an independent risk factor for unplanned hospital admission or readmission among patients scheduled for ambulatory surgery in a tertiary medical center. PATIENTS AND METHODS: Existing databases were used to identify 235 obese patients (body mass index [BMI] >40) scheduled for ambulatory surgery from January 2, 2002, through December 31, 2003, at Mayo Clinic's site in Rochester, MN. Each patient was matched to a normal-weight control (BMI <25) by age, sex, surgical procedure, type of anesthesia, and date of surgery, and the medical records of all patients were reviewed. Conditional logistic regression analysis was performed to assess whether obesity is an independent risk factor for unplanned postoperative hospital admission. In all cases, 2-sided tests were performed. P<.05 was considered statistically significant. RESULTS: Obese patients (mean +/- SD BMI, 44+/-4) were matched with control patients (mean +/- SD BMI, 23+/-2). Comorbidity was more frequent in the obese cohort. The frequency of unplanned hospital admission did not differ between groups: 61 obese patients (26.0%) and 52 control patients (22.1%) were admitted (odds ratio, 1.3; 95% confidence interval, 0.8-2.0; P=.30). CONCLUSION: Obesity is not a significant independent risk factor for unplanned admission after ambulatory surgery, suggesting that obesity per se should not prevent ambulatory surgery from being scheduled.

Periorbital ecchymoses during general anesthesia in a patient with primary amyloidosis: a harbinger for bleeding?

Primary amyloidosis is a result of proliferation of a population of plasma cells that leads to an increased secretion of monoclonal immunoglobulins (amyloid). Amyloid protein infiltrates increase capillary fragility. Such capillaries can burst, even after minor stress, resulting in periorbital hemorrhage. We describe a 64-yr-old man with primary amyloidosis who underwent general anesthesia. His eyes were gently closed with tape. Upon removal of the tape bilateral periorbital purpura was noted. All coagulation studies were normal. The periorbital hemorrhage was attributed to amyloidosis-induced capillary fragility.

Anesthesia for a patient with morbid obesity using dexmedetomidine without narcotics.

PURPOSE: To describe the anesthetic management of a patient with extreme obesity undergoing bariatric surgery whose intraoperative narcotic management was entirely substituted with dexmedetomidine. CLINICAL FEATURES: We describe a 433-kg morbidly obese patient with obstructive sleep apnea and pulmonary hypertension who underwent Roux-en-Y gastric bypass. Because of the concern that the use of narcotics might cause postoperative respiratory depression, we substituted their intraoperative use with a continuous infusion of dexmedetomidine (0.7 microg.kg(-1).hr(-1)). The anesthesia course was uneventful, and the intraoperative use of dexmedetomidine was associated with low anesthetic requirements (0.5 minimum alveolar concentration). After completion of the operation and after tracheal extubation, the dexmedetomidine infusion was continued uninterrupted throughout the end of the first postoperative day. The analgesic effects of dexmedetomidine extended narcotic-sparing effects into the postoperative period; the patient had lower narcotic requirements during the first postoperative day [48 mg of morphine by patient-controlled analgesia (PCA)] while still receiving dexmedetomidine, compared to the second postoperative day (morphine 148 mg by PCA) with similar pain scores. CONCLUSION: Dexmedetomidine may be a useful anesthetic adjunct for patients who are susceptible to narcotic-induced respiratory depression. In this morbidly obese patient the narcotic-sparing effects of dexmedetomidine were evident both intraoperatively and postoperatively.

Intrathecal anesthesia and recovery from radical prostatectomy: a prospective, randomized, controlled trial.

BACKGROUND: Previous studies suggest that intraoperative anesthetic care may influence postoperative pain and recovery from surgery. The authors tested the hypothesis that the addition of intrathecal analgesia to general anesthesia would improve long-term functional status and decrease pain in patients undergoing radical retropubic prostatectomy. METHODS: One hundred patients received either general anesthesia supplemented with intravenous fentanyl or general anesthesia preceded by intrathecal administration of bupivacaine (15 mg), clonidine (75 microg), and morphine (0.2 mg). Patients and providers were masked to treatment assignment. All patients received multimodal pain management postoperatively. Primary outcomes included pain and functional status over the first 12 postoperative weeks. RESULTS: Patients receiving intrathecal analgesia required more intravenous fluids and vasopressors intraoperatively. Pain was well controlled throughout the study (mean numerical pain scores < 3 in both groups at all times studied). Intrathecal analgesia decreased pain and supplemental intravenous morphine use over the first postoperative day but increased the frequency of pruritus. Pain and functional status after discharge from the hospital did not differ between groups. Intrathecal analgesia significantly decreased the duration of hospital stay (from 2.8 +/- 2.0 to 2.1 +/- 0.5 days; P < 0.01) as a result of five patients in the control group who stayed in the hospital more than 3 days. CONCLUSIONS: The benefits of improved immediate analgesia and decreased morphine requirements resulting from intrathecal analgesia must be weighed against factors such as pruritus, increased intraoperative requirement for fluids and vasopressors, and resources needed to implement this modality. Further studies are needed to determine the significance of the decrease in duration of hospital stay.