Permissive Hypotension in Rhinoplasty: A Literature Review of Therapeutics and Associated Outcomes.

BACKGROUND/PURPOSE: Permissive hypotension, defined as mean arterial pressure (MAP) of 60-70 mm Hg, has been regarded as favorable among surgeons performing rhinoplasty. Furthermore, management of blood pressure has been shown to promote greater visualization of the surgical field and decrease postoperative complications, such as ecchymosis and edema. While multiple therapies have been utilized to achieve permissive hypotension, it remains unclear how modalities compare in terms of safety and efficacy. The purpose of this study was to conduct a systematic review to better understand the specific modalities and associated outcomes in managing blood pressure during rhinoplasty. METHODS: A systematic literature review was conducted in order to identify and assess therapeutics utilized in achieving permissive hypotension during rhinoplasty. Variables collected included year of publication, journal, article title, organization of study, patient sample, treatment modality, associated outcomes (i.e., intraoperative bleeding, edema, and ecchymosis), adverse events, complications, and satisfaction. Articles were then categorized by the level of evidence as set forth by the American Society of Plastic Surgeons. Any conflicts were resolved through discussion and full-text review among co-authors. Of note, the search was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. No funding was required to conduct this review of the literature. RESULTS: Initial review yielded sixty-five articles. Title and abstract review followed by standardized application of inclusion and exclusion criteria resulted in a total of ten studies for analysis. Articles discussed multiple therapies for management of blood pressure during rhinoplasty, including dexmedetomidine, dexamethasone, gabapentin, labetalol, nitroglycerine, remifentanil, magnesium sulfate, clonidine, and metoprolol. Overall, intraoperative bleeding, as well as postoperative ecchymosis and edema were reduced when MAP was controlled. CONCLUSION: Given its intra- and postoperative benefits, permissive hypotension can be leveraged to improve outcomes in rhinoplasty. This study presents an updated comprehensive review of various modalities used to achieve permission hypotension in rhinoplasty. Future studies should explore how comorbidities may impact choice of treatment regimen among patients undergoing rhinoplasty. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Effect of Throat Pack Placement on the Incidence of Sore Throat and Postoperative Nausea and Vomiting in Septorhinoplasty Patients: A Randomized Controlled Trial.

BACKGROUND: Advances in surgical and anesthetic techniques have led to a growing interest in performing procedures at ambulatory surgery centers. However, procedures involving the oropharyngeal or nasopharyngeal region may lead to the ingestion of blood, which can lead to postoperative nausea and vomiting (PONV). To date, limited studies have largely failed to demonstrate the benefits of oropharyngeal throat packing. OBJECTIVES: The authors aimed to investigate whether throat packing during elective septorhinoplasty increases the incidence of postoperative throat pain and assess its effects on PONV. METHODS: A randomized, prospective, single-blinded study was performed on 101 patients undergoing elective septorhinoplasty who received oropharyngeal throat packing vs no packing to compare the incidence of PONV and throat pain in the immediate postoperative period in addition to postoperative day (POD) 1 and 2. RESULTS: The incidence and severity of postoperative throat pain were significantly greater in patients receiving throat packs in the immediate postoperative period and on POD 1. Significant differences in throat pain and incidence between the 2 groups diminished by POD 2. Patients having received throat packs also demonstrated a higher utilization of opioids in postanesthesia care unit. The incidence of PONV did not significantly differ between the 2 cohorts at any point of observations. CONCLUSIONS: The results of this study largely agree with previous data that throat packs may contribute to postoperative throat pain while not significantly altering the incidence of PONV. Considering these data, we do not recommend routine utilization of throat packing during elective septorhinoplasty.

Randomized controlled trial of a quadratus lumborum block with liposomal bupivacaine for postoperative analgesia in laparoscopic donor nephrectomy.

Perioperative pain management is an important consideration in early recovery and patient satisfaction following laparoscopic donor nephrectomy. Transmuscular quadratus lumborum block has been described to reduce pain and opioid usage following several abdominal surgeries. In this prospective single-blind randomized controlled trial, we compared 52 patients who adhered to our institutional donor nephrectomy Early Recovery After Surgery pathway, which includes a laparoscopic-guided transversus abdominus plane block, to 40 patients who additionally received a transmuscular quadratus lumborum block with liposomal bupivacaine. Compared to control patients, those who received the block spent longer in the operating room prior to the surgical start (65.4 vs. 51.6 min, P < .001). Both groups had similar total hospital length of stay (33.3 h vs. 34.4 h, P = .61). Pain scores from postoperative days 0-30, number of patients requiring opioids, postoperative nausea, and pain management satisfaction were similar between both groups. Patients who received the block consumed less opioid on postoperative day 1 compared to controls (P = .006). No complications were attributable to the block. The quadratus lumborum block provides a safe pain management adjunct for some patients, and may reduce opioid use in the early postoperative period when combined with our standard institutional protocol for kidney donors.

Involvement of Opioid Receptors in the Lipid Rescue of Bupivacaine-Induced Cardiotoxicity.

BACKGROUND: Lipid emulsion (LE) has been successfully used for resuscitation of local anesthetic cardiotoxicity caused by bupivacaine overdose. Opioid receptors have been shown to play a key role in cardio protection. We explored whether this rescue action of LE is mediated through opioid receptors. METHODS: Asystole was induced by bupivacaine (10 mg/kg over 20 seconds, IV) in young male Sprague-Dawley rats, and resuscitation with LE (intralipid 20%; 5 mL/kg bolus and 0.5 mL/kg/min maintenance) was started immediately. The rats were pretreated 2 minutes before inducing asystole with nonselective opioid receptor antagonists such as naloxone and naloxone methiodide, as well as highly selective opioid receptor antagonists for subtype κ, δ, and µ or phosphate buffer solution as a control. Heart rates and ejection fractions were measured using echocardiography. RESULTS: LE rescue of bupivacaine cardiotoxicity was prevented by high-dose (1 mg/kg) naloxone but not by lower doses of naloxone (1, 5, and 10 µg/kg), by naloxone methiodide (which does not cross the blood-brain barrier), and by a selective δ- and κ-opioid receptor antagonists at a higher (10 mg/kg) dose. Successful LE rescue was not affected by highly selective µ-opioid receptor antagonists. δ-Opioid receptor antagonist (10 mg/kg) pretreatment also resulted in reduced phosphorylation level of cardiac glycogen synthase kinase-3ß in rats that were not resuscitated by LE compared with control. CONCLUSIONS: Our data highlight the involvement of peripheral δ- and κ-opioid receptors in the rescue action of LE.

Sugammadex: A Comprehensive Review of the Published Human Science, Including Renal Studies.

Although neuromuscular block (NMB) allows immobility for airway management and surgical exposure, termination of its effect is limited by and associated with side effects of acetylcholinesterase inhibitors. Sugammadex is a selective relaxant binding agent that has been shown to reverse deep NMB, even when administered 3 minutes following a 1.2 mg/kg dose of rocuronium. This novel drug is a modified gamma cyclodextrin, that through encapsulation process terminates the effects of rocuronium and vecuronium (aminosteroid muscle relaxants), and enables the anesthesiologists rapidly to reverse profound NMB induced by rocuronium or vecuronium, in a "can't ventilate, can't intubate" crisis. In this review, data from published phase 1, 2, and 3 clinical trials are reviewed and presented. In addition, clinical trials on special patient populations (patients with pulmonary disease and renal insufficiency) are evaluated. Each article reviewed will conclude with a discussion of relevance, focus on adverse event profile, and clinical usefulness.

Fatty-acid oxidation and calcium homeostasis are involved in the rescue of bupivacaine-induced cardiotoxicity by lipid emulsion in rats.

OBJECTIVES: Lipid emulsion has been shown to be effective in resuscitating bupivacaine-induced cardiac arrest but its mechanism of action is not clear. Here we investigated whether fatty-acid oxidation is required for rescue of bupivacaine-induced cardiotoxicity by lipid emulsion in rats. We also compared the mitochondrial function and calcium threshold for triggering of mitochondrial permeability transition pore opening in bupivacaine-induced cardiac arrest before and after resuscitation with lipid emulsion. DESIGN: Prospective, randomized animal study. SETTING: University research laboratory. SUBJECTS: Adult male Sprague-Dawley rats. INTERVENTIONS: Asystole was achieved with a single dose of bupivacaine (10 mg/kg over 20 secs, intravenously) and 20% lipid emulsion infusion (5 mL/kg bolus, and 0.5 mL/kg/min maintenance), and cardiac massage started immediately. The rats in CVT-4325 (CVT) group were pretreated with a single dose of fatty-acid oxidation inhibitor CVT (0.5, 0.25, 0.125, or 0.0625 mg/kg bolus intravenously) 5 mins prior to inducing asystole by bupivacaine overdose. Heart rate, ejection fraction, fractional shortening, the threshold for opening of mitochondrial permeability transition pore, oxygen consumption, and membrane potential were measured. The values are mean ± SEM. MEASUREMENTS AND MAIN RESULTS: Administration of bupivacaine resulted in asystole. Lipid Emulsion infusion improved the cardiac function gradually as the ejection fraction was fully recovered within 5 mins (ejection fraction=64±4% and fractional shortening=36±3%, n=6) and heart rate increased to 239±9 beats/min (71% recovery, n=6) within 10 mins. Lipid emulsion was only able to rescue rats pretreated with low dose of CVT (0.0625 mg/kg; heart rate~181±11 beats/min at 10 mins, recovery of 56%; ejection fraction=50±1%; fractional shortening=26±0.6% at 5 mins, n=3), but was unable to resuscitate rats pretreated with higher doses of CVT (0.5, 0.25, or 0.125 mg/kg). The calcium-retention capacity in response to Ca²âº overload was significantly higher in cardiac mitochondria isolated from rats resuscitated with 20% lipid emulsion compared to the group that did not receive Lipid Emulsion after bupivacaine overdose (330±42 nmol/mg vs. 180±8.2 nmol/mg of mitochondrial protein, p<.05, n=3 in each group). The mitochondrial oxidative rate and membrane potential were similar in the bupivacaine group before and after resuscitation with lipid emulsion infusion. CONCLUSIONS: Fatty-acid oxidation is required for successful rescue of bupivacaine-induced cardiotoxicity by lipid emulsion. This rescue action is associated with inhibition of mitochondrial permeability transition pore opening.

Intralipid prevents and rescues fatal pulmonary arterial hypertension and right ventricular failure in rats.

Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling leading to right ventricular (RV) hypertrophy and failure. Intralipid (ILP), a source of parenteral nutrition for patients, contains γ-linolenic acid and soy-derived phytoestrogens that are protective for lungs and heart. We, therefore, investigated the therapeutic potential of ILP in preventing and rescuing monocrotaline-induced PAH and RV dysfunction. PAH was induced in male rats with monocrotaline (60 mg/kg). Rats then received daily ILP (1 mL of 20% ILP per day IP) from day 1 to day 30 for prevention protocol or from day 21 to day 30 for rescue protocol. Other monocrotaline-injected rats were left untreated to develop severe PAH by day 21 or RV failure by approximately day 30. Saline or ILP-treated rats served as controls. Significant increase in RV pressure and decrease in RV ejection fraction in the RV failure group resulted in high mortality. Therapy with ILP resulted in 100% survival and prevented PAH-induced RV failure by preserving RV pressure and RV ejection fraction and preventing RV hypertrophy and lung remodeling. In preexisting severe PAH, ILP attenuated most lung and RV abnormalities. The beneficial effects of ILP in PAH seem to result from the interplay of various factors, among which preservation and/or stimulation of angiogenesis, suppression and/or reversal of inflammation, fibrosis and hypertrophy, in both lung and RV, appear to be major contributors. In conclusion, ILP not only prevents the development of PAH and RV failure but also rescues preexisting severe PAH.

Phosphorylation of GSK-3ß mediates intralipid-induced cardioprotection against ischemia/reperfusion injury.

BACKGROUND: Intralipid (Sigma, St. Louis, MO), a brand name for the first safe fat emulsion for human use, has been shown to be cardioprotective. However, the mechanism of this protection is not known. The authors investigated the molecular mechanism(s) of Intralipid-induced cardioprotection against ischemia/reperfusion injury, particularly the role of glycogen synthase kinase-3ß (GSK-3ß) and mitochondrial permeability transition pore in this protective action. METHODS: In vivo rat hearts or isolated Langendorff-perfused mouse hearts were subjected to ischemia followed by reperfusion with Intralipid (1% in ex vivo and one bolus of 20% in in vivo) or vehicle. The hemodynamic function, infarct size, threshold for the opening of mitochondrial permeability transition pore, and phosphorylation levels of protein kinase B (Akt)/extracellular signal regulating kinase (ERK)/GSK-3ß were measured. RESULTS: Administration of Intralipid at the onset of reperfusion resulted in approximately 70% reduction in infarct size in the in vivo rat model. Intralipid also significantly improved functional recovery of isolated Langendorff-perfused mouse hearts as the rate pressure product was increased from 2,999 ± 863 mmHg*beats/min in the control group to 13,676 ± 611 mmHg*beats/min (mean±SEM) and the infarct size was markedly smaller (18.3 ± 2.4% vs. 54.8 ± 2.9% in the control group, P < 0.01). The Intralipid-induced cardioprotection was fully abolished by LY294002, a specific inhibitor of PI3K, but only partially by PD98059, a specific ERK inhibitor. Intralipid also increased the phosphorylation levels of Akt/ERK1/glycogen synthase kinase-3ß by eightfold, threefold, and ninefold, respectively. The opening of mitochondrial permeability transition pore was inhibited by Intralipid because calcium retention capacity was higher in the Intralipid group (274.3 ± 8.4 nM/mg vs. 168.6 ± 9.6 nM/mg in the control group). CONCLUSIONS: Postischemic treatment with Intralipid inhibits the opening of mitochondiral permeability transition pore and protects the heart through glycogen synthase kinase-3ß via PI3K/Akt/ERK pathways.

Ultrasound-guided peripheral nerve block.

With the common use of ultrasound imaging by anesthesiologists, especially for peripheral nerve blocks, this article will review basic physics of ultrasound machine, use of ultrasound in regional anesthesia, review of recent reports in the literature, and the outcome data.