Midazolam Premedication Immediately Before Surgery Is Not Associated With Early Postoperative Delirium.

BACKGROUND: Postoperative delirium is common among older surgical patients and may be associated with anesthetic management during the perioperative period. The aim of this study is to assess whether intravenous midazolam, a short-acting benzodiazepine used frequently as premedication, increased the incidence of postoperative delirium. METHODS: Analyses of existing data were conducted using a database created from 3 prospective studies in patients aged 65 years or older who underwent elective major noncardiac surgery. Postoperative delirium occurring on the first postoperative day was measured using the confusion assessment method. We assessed the association between the use or nonuse of premedication with midazolam and postoperative delirium using a χ2 test, using propensity scores to match up with 3 midazolam patients for each control patient who did not receive midazolam. RESULTS: A total of 1266 patients were included in this study. Intravenous midazolam was administered as premedication in 909 patients (72%), and 357 patients did not receive midazolam. Those who did and did not receive midazolam significantly differed in age, Charlson comorbidity scores, preoperative cognitive status, preoperative use of benzodiazepines, type of surgery, and year of surgery. Propensity score matching for these variables and American Society of Anesthesiology physical status scores resulted in propensity score-matched samples with 1-3 patients who used midazolam (N = 749) for each patient who did not receive midazolam (N = 357). After propensity score matching, all standardized differences in preoperative patient characteristics ranged from -0.07 to 0.06, indicating good balance on baseline variables between the 2 exposure groups. No association was found between premedication with midazolam and incident delirium on the morning of the first postoperative day in the matched dataset, with odds ratio (95% confidence interval) of 0.91 (0.65-1.29), P = .67. CONCLUSIONS: Premedication using midazolam was not associated with higher incidence of delirium on the first postoperative day in older patients undergoing major noncardiac surgery.

Awake Sedation With Propofol Attenuates Intraoperative Stress of Carotid Endarterectomy in Regional Anesthesia.

BACKGROUND: Carotid endarterectomy in regional anesthesia is often associated with increased perioperative stress. We assumed that carotid endarterectomy performed under awake sedation with propofol is more beneficial to prevent such stress than alprazolam premedication only. METHODS: A total of 47 consecutive patients with significant carotid artery stenosis were enrolled into this investigation and followed up for 5 years to explore vascular complications. All operations were performed under regional anesthesia. As premedication, all patients took 0.5 mg of alprazolam 30 minutes before the procedure. After randomization, 22 patients had awake sedation with target controlled propofol infusion, and the other 25 had only premedication. Cortisol plasma levels were serially analyzed: before surgery (T1), before (T2) and after release of carotid clamp (T3), and at 2 (T4) and 24 postoperative hours (T5). Alprazolam levels were also measured before and after the surgery. RESULTS: The plasma concentration of cortisol was significantly lower in the propofol sedation group at T2 (P < 0.001), T3 (P = 0.001), and T4 (P < 0.001) than in the alprazolam-only group. Alprazolam levels did not correlate with cortisol levels at any time point. A significant positive correlation was found between the clamp time and plasma cortisol level at T3 (P = 0.018), similarly between the degree of contralateral carotid stenosis and plasma cortisol level at T3 (P = 0.03). Plasma cortisol concentration 2 hours after the operation (T4) proved to be an independent predictor of carotid restenosis during the 5-year follow-up (odds ratio: 1.67, 95% confidence interval: 1.02-2.73, P = 0.04). CONCLUSIONS: An additional intraoperative propofol sedation provides better stress relief than alprazolam-only premedication during awake carotid endarterectomy.

Postinduction apnoea in dogs premedicated with acepromazine or dexmedetomidine and anaesthetized with alfaxalone or propofol.

OBJECTIVE: To compare incidence and duration of postinduction apnoea in dogs after premedication with methadone and acepromazine (MA) or methadone and dexmedetomidine (MD) followed by induction with propofol (P) or alfaxalone (A). STUDY DESIGN: Prospective, randomized clinical trial. ANIMALS: A total of 32 American Society of Anesthesiologists class I dogs (15 females, 17 males), aged between 4 months and 4 years, weighing between 3 and 46 kg. METHODS: Dogs were randomly allocated to be administered MA+P, MA+A, MD+P or MD+A (methadone 0.5 mg kg-1 and acepromazine 0.05 mg kg-1 or dexmedetomidine 5 µg kg-1). Induction agents were administered intravenously via syringe driver (P at 4 mg kg-1 minute-1 or A at 2 mg kg-1 minute-1) until successful endotracheal intubation and the endotracheal tube connected to a circle system with oxygen flow at 2 L minute-1. Oxygen saturation of haemoglobin (SpO2), end tidal partial pressure of carbon dioxide and respiratory rate were monitored continuously. If apnoea (≥ 30 seconds without breathing) occurred, the duration until first spontaneous breath was measured. If SpO2 decreased below 90% the experiment was stopped and manual ventilation initiated. Data were analysed with general linear models with significance set at p ≤ 0.05. RESULTS: There was no statistical difference in the incidence (11 of 16 dogs in A groups and 12 of 16 dogs in P groups), or mean ± standard deviation duration (A groups 125 ± 113 seconds, P groups 119 ± 109 seconds) of apnoea. The SpO2 of one dog in the MD+P group decreased below 90% during the apnoeic period. CONCLUSIONS AND CLINICAL RELEVANCE: Propofol and alfaxalone both cause postinduction apnoea and the incidence and duration of apnoea is not influenced by the use of acepromazine or dexmedetomidine in premedication. Monitoring of respiration is recommended when using these premedication and induction agent combinations.

Incidence of bradycardia at arrival to the operating room after oral or intravenous premedication with clonidine in children.

BACKGROUND: Clonidine has been advocated as a valid alternative for premedication in children but one of the few limitations is its association with reduced heart rate (HR), which thus raises the question of the safety of clonidine as premedication in children. The aim of this study was to investigate the incidence of bradycardia in children premedicated with oral or intravenous clonidine as compared to children not receiving pharmacologic premedication. METHODS: An open, nonrandomized, observational study design was used. During the preoperative assessment visit the children were prescribed no premedication, intravenous or oral clonidine. On arrival to the operating room (OR) HR was recorded by connecting the patient to standard monitoring with pulseoximetry and/or Electrocardiogram. The primary outcome measure was the number of patients with a HR below 85% of the lower limit of the normal range (1st centile), which was defined as bradycardia that might need clinical intervention. RESULTS: One thousand five hundred and seven patients were included in the analysis. 600 and 85 patients did not receive any premedication (Group 0), 305 patients received iv Clonidine (Group CIV), and 517 patients were given oral Clonidine (Group CPO). One patient in Group 0 (0.15%; 95% CI: 0-0.81%), none in Group CIV (0%; 95% CI: 0.00-0.98%), and 5 patients in Group CPO (0.97%; 95% CI: 0.31-2.24%) were observed to have a HR of <85% of the 1st centile. CONCLUSION: The incidence of bradycardia following oral or intravenous premedication with clonidine in a pediatric population scheduled for anesthesia is low. Thus, it does not appear rational to refrain from using clonidine as premedication in children only due to fear of bradycardia.

Efficacy of maropitant in preventing vomiting in dogs premedicated with hydromorphone.

OBJECTIVE: The goal of this study was to evaluate the effectiveness of maropitant (Cerenia(®)) in preventing vomiting after premedication with hydromorphone. STUDY DESIGN: Randomized, blinded, prospective clinical study. ANIMALS: Eighteen dogs ASA I/II admitted for elective orthopedic surgical procedures. The dogs were a mixed population of males and females, purebreds and mixed breeds, 1.0-10.2 years of age, weighing 3-49.5 kg. METHODS: Dogs were admitted to the study if they were greater than 1 year of age, healthy and scheduled to undergo elective orthopedic surgery. Dogs were randomly selected to receive one of two treatments administered by subcutaneous injection. Group M received 1.0 mg kg(-1) of maropitant, Group S received 0.1 mL kg(-1) of saline 1 hour prior to anesthesia premedication. Dogs were premedicated with 0.1 mg kg(-1) of hydromorphone intramuscularly. A blinded observer documented the presence of vomiting, retching and/or signs of nausea for 30 minutes after premedication. RESULTS: All dogs in S vomited (6/9), retched (1/9) or displayed signs of nausea (2/9). None (0/9) of the dogs in M vomited, retched or displayed signs of nausea. Dogs in M had significantly fewer incidences of vomiting (p=0.0090), vomiting and retching (p=0.0023) and vomiting, retching and nausea (p<0.0001) when compared to S. CONCLUSION AND CLINICAL RELEVANCE: Maropitant prevents vomiting, retching and nausea associated with intramuscular hydromorphone administration in dogs.

Risk of anaesthetic mortality in dogs and cats: an observational cohort study of 3546 cases.

OBJECTIVE: To evaluate the anaesthetic death risk for dogs and cats in a French private practice. STUDY DESIGN: Observational cohort study. ANIMAL POPULATION: All small animals anesthetized at the Centre Hospitalier Vétérinaire des Cordeliers between April 15th, 2008 and April 15th, 2010. METHODS: General anaesthesia was defined as a drug-induced unconsciousness characterised by a controlled and reversible depression of the central nervous system and analgesia, sufficient to allow endotracheal intubation. Patient outcome (alive or dead) was assessed at the end of anaesthesia defined as the meeting point of the return of consciousness, rectal temperature >36 °C and ability to maintain sternal recumbency. Death occurring during anaesthesia was recorded. Relationship between anaesthetic death and ASA status, species, age, nature of the procedure, anaesthetic protocol and occurrence of epidural administration of a combination of morphine and bupivacaine were analysed. RESULTS: During the study period 3546 animals underwent general anaesthesia. The overall death rate in the present study was 1.35% (48 in 3546, 95% CI 0.96-1.75). The death rate of healthy animals (ASA 1 and 2) was 0.12% (3 in 2602 95% CI 0.02-0.34). For sick animals (ASA status 3 and over), the overall death rate was 4.77% (45 in 944 95% CI 3.36-6.18). The death rates in the ASA 3, 4 and 5 categories were 2.90%, 7.58% and 17.33%, respectively. The main factor associated with increased odds of anaesthetic death in ASA categories 3 and over was poor health status (ASA physical status classification). The nature of the procedure the patient underwent and epidural administration of a combination of morphine and bupivacaine were not correlated with the occurrence of death during anaesthesia. Neither species nor age effects were detected. CONCLUSION AND CLINICAL RELEVANCE: Specific factors were associated with increased odds of anaesthetic death, especially poor health status. Efforts must be directed towards thorough preoperative patient evaluation and improvement of clinical conditions if possible. Identification of risk factors before anaesthesia should lead to increased surveillance by trained staff. This could result in better outcomes.

A comparison of anesthetic complications between diabetic and nondiabetic dogs undergoing phacoemulsification cataract surgery: a retrospective study.

OBJECTIVE: To compare the incidence of anesthetic complications in diabetic and nondiabetic dogs undergoing general anesthesia and phacoemulsification cataract surgery. PROCEDURE: The medical and anesthetic records of all dogs undergoing phacoemulsification cataract surgery at Davies Veterinary Specialists between 2005 and 2008 were reviewed. Anesthetic records were evaluated by an ECVAA Diplomate. Dogs for which records were incomplete were excluded. The anesthetic technique, including all drugs administered in the perioperative period, was recorded. The anesthetic complications investigated included hypotension (MAP (mmHg): >or=55 none/mild; 13.75 mmol/L (250 mg/dL)) in the diabetic group was also assessed. RESULTS: 66 diabetic and 64 nondiabetic dogs were included in the study. Diabetic dogs were more likely to develop moderate and severe intraoperative hypotension than nondiabetic dogs. Forty-four percent of diabetic dogs had at least one episode of severe hyperglycemia whilst anesthetized. CONCLUSIONS: Diabetic dogs undergoing phacoemulsification are more likely to suffer the anesthetic complications of moderate and severe hypotension than nondiabetic dogs. The increased incidence and severity of hypotension in diabetic dogs may be explained by hypovolemia secondary to hyperglycemia and resultant osmotic diuresis.

No Pain, More Gain: Reduced Postoperative Opioid Consumption with a Standardized Opioid-Sparing Multimodal Analgesia Protocol in Opioid-Tolerant Patients Undergoing Colorectal Surgery.

The utility of opioid-sparing multimodal analgesia protocols (OSMMAPs) in opioid-tolerant (OT) patients is unknown. We sought to determine the impact of a standardized OSMMAP in OT versus opioid-naïve (ON) patients after major colorectal surgery. Consecutive patients undergoing surgery before (January 2015-March 2017) and after OSMMAP implementation (April 2017-March 2018) were identified from a single-institution prospective colorectal surgery registry. OT was defined by the presence of an opioid on the preadmission medication record. Opioid use (measured in oral morphine equivalents (OMEs)) and surgical outcomes were compared between OT and ON patients pre- and post-OSMMAP. The study cohort of 201 patients included 59 OT patients (25 pre- and 34 post-OSMMAP) and 142 ON controls (34 pre- and 108 post-OSMMAP). The median age was 47.5 years (IQR 32), and 50% were male. 185 patients (92%) had a laparoscopic/robotic resection and 16 (8%) open. There were statistically significant reductions in OME required post-OSMMAP on each postoperative day (days 1 to 4) and cumulative OME for both OT and ON patients. The reduction in opioid requirements was significantly larger in OT than ON patients. We present the first study highlighting a larger opioid usage reduction in OT than in ON patients after OSMMAP implementation.

Surgical bleeding after pre-operative unfractionated heparin and low molecular weight heparin for coronary bypass surgery.

BACKGROUND AND OBJECTIVES: Since the impairment of platelet function may cause excess peri-operative bleeding, pre-operative discontinuation of aspirin and heparin bridging are common for cardiac surgery. We evaluated the impact of pre-operative administration of enoxaparin and unfractionated heparin (UFH) on coagulation parameters and peri-operative bleeding in patients undergoing elective coronary artery bypass grafting (CABG) surgery after discontinuation of aspirin. DESIGN AND METHODS: Forty-three patients with three-vessel coronary artery disease undergoing elective CABG surgery discontinued aspirin and were randomized to receive either UFH 180 UI/Kg x 2/day s.c. or enoxaparin 100 UI/Kg x 2/day s.c. until 12 h before surgery (median pre-operative treatment 8 days, range 6-12 days). Surgery was performed as usual with UFH. Neither UFH nor any low molecular weight heparin was given in the immediate post-operative period. The effects of UFH and enoxaparin were monitored by the activated partial thromboplastin time (aPTT) and the Enox-test (sensitive to factor Xa inhibition) using a Rapidpoint Coagulation Analyzer. aPTT and factor Xa activity were also measured by standard methods. Peri-operative bleeding and the nadirs of hemoglobin concentration, hematocrit and platelet count were monitored post-operatively. RESULTS: Patients in the two groups were similar for number of bypasses, on-pump time, total surgery time, and time from the last heparin administration. Coagulation parameters increased significantly and similarly at 30 min and 6 h with both treatments, but returned within the normal range at 12 h. Hemoglobin, hematocrit and platelet counts significantly decreased to the same extent after CABG and re-normalized at the same time. Transfusional requirements of blood and plasma units were similar in the two groups. INTERPRETATION AND CONCLUSIONS: From the kinetics of coagulation parameters and the evaluation of bleeding, enoxaparin is a safe alternative to UFH as a bridging therapy to CABG after discontinuation of aspirin.

[Optimization of anesthetic maintenance of a facial dermabrasion operation].

Facial dermabrasion requires the preservation of natural mimic muscle tone, adequate spontaneous respiration, and contact with a patient. By taking into account the commercial pattern of surgical interventions, anesthesia should be as safe and comfortable as possible. For these purposes, the standard procedure of intravenous anesthesia with spontaneous respiration being preserved is optimized on the anticipatory analgesia principle, by using analgesics having the non-opiate mechanism of action: the kininogenesis inhibitor transamine and the nonsteroidal anti-inflammatory drug ketonal. This makes it possible to provide the adequacy of anesthesia and a good cardiovascular response with the doses of narcotic analgesics, hypnotics, and an anxiolytics, which do not cause respiratory distress, and to avoid using narcotic analgesics. The use of the antiemetics tropisetron and dexamethasone at the induction stage of anesthesia has been ascertained to be a reliable preventive measure against postoperative nausea and vomiting, by substantially enhancing its comfortability.

An allergic reaction following intramuscular administration of ketamine and midazolam.

A 6-year-old female in good health presented with no known drug allergies for dental treatment under general anesthesia. Following the preoperative evaluation, the patient received intramuscular premedication consisting of midazolam (1 mg) and Ketamine (60 mg) into the left deltoid muscle. During patient transfer, anesthesia personnel detected a hive developing in proximity to the patient's right ear lobe. The subject was directly placed into the operative chair, and a physical exam revealed urticaria on the neck, back, and torso. In addition, an audible wheeze was detected with lung auscultation. Investigations carried out after the incident revealed a positive reaction to ketamine

A comparative study of cognitive behavior therapy versus general anesthesia for painful medical procedures in children.

A treatment outcome study was conducted to compare the efficacy of cognitive behavior therapy (CBT) versus general anesthesia in alleviating the distress of 18 pediatric cancer patients (ages: 3-12 years) undergoing bone marrow aspirations (BMAs). CBT and short-acting mask anesthesia were delivered within a repeated-measures counterbalance design. Results indicated that children exhibited more behavioral distress in the CBT condition for the 1st minute lying down on the treatment table. However, parents rated significantly more behavioral adjustment symptoms 24 h following the BMA when their children had received anesthesia. No differences were found in childrens' and parents' preference for CBT versus anesthesia.

Acute pancreatitis complicating a bone marrow harvest.

A patient developing acute pancreatitis with pseudocyst formation after an uncomplicated bone marrow harvest is reported. The diagnosis was confirmed by elevated serum amylase and lipase, and by CT scan. We suggest that the pancreatitis may have been precipitated by spasm of the sphincter of Oddi secondary to opiates administered as premedication and for pain relief.

Effects of benzodiazepines on explicit memory in a paediatric surgery setting.

RATIONALE: Many laboratory-based studies indicate that benzodiazepines impair explicit memory performance, increase sedation, and impair attention. OBJECTIVES: The present study was designed to extend prior lab-based findings to an applied setting in which the amnestic effects of benzodiazepines may be beneficial for users. In addition, the study extended the previous adult-focused research by examining the cognitive effects of benzodiazepines in children. METHODS: The present study examined the use of a specific benzodiazepine (midazolam) as a premedicant among 40 children aged 4-6 years old having ear tube (myringotomy) surgery, who were randomly assigned to receive midazolam or placebo. RESULTS: Consistent with previous studies, the results indicated that midazolam causes significant amnesia on a cued recall task. In addition, free recall for post-drug events were also impaired by midazolam relative to placebo, indicating that benzodiazepine-induced amnesia occurs even for highly salient information. CONCLUSIONS: Overall, it appears that benzodiazepines do impair memory in a pediatric population. This amnesia was not secondary to the inattention and sedation also caused by midazolam administration. The theoretical and clinical implications of these findings are discussed, as are potential future studies.

Safety considerations in the use of drug combinations during general anaesthesia.

The most commonly employed technique for providing general anaesthesia uses a balanced approach, where different drugs are used to reach specific desired endpoints. The variety of drugs used can result in a dozen or more different compounds being administered during a 'routine anaesthetic' procedure. Drug interactions are quite common and their clinical effects can be very significant. Clinically, general anaesthesia has 4 goals. These are: unconsciousness/amnesia; analgesia; muscle relaxation and maintenance of homeostasis. The anaesthesiologist tries to select only those drugs that permit a rapid onset of desirable operative conditions so that surgery can be performed properly and rapidly. Such drugs should also minimally disturb the patient's preoperative homeostatic maintenance, and maximise return to a desirable postanaesthetic functional state.