Hypercarbia and high-flow nasal oxygen use during anaesthesia - risking a failure to thrive?

Prevention of arterial oxygen desaturation during anaesthesia with high-flow nasal oxygen (HFNO) has gained greater acceptance for a widening range of procedures. However, during HFNO use there remains the potential for development of significant anaesthesia-associated apnoea or hypoventilation and the possibility of hypercarbia, with harmful cardiovascular or neurological sequelae. The aim of this study was to determine whether any HFNO-related hypercarbia adverse incidents had been reported on webAIRS, an online database of adverse anaesthesia-related incidents. Two relevant reports were identified of complications due to marked hypercarbia during HFNO use to maintain oxygenation. In both reports, HFNO and total intravenous anaesthesia were used during endoscopic procedures through the upper airway. In both, the extent of hypoventilation went undetected during HFNO use. An ensuing cardiac arrest was reported in one report, ascribed to acute hypercarbia-induced exacerbation of the patient's pre-existing pulmonary hypertension. In the other report, hypercarbia led to a prolonged duration of decreased level of consciousness post procedure, requiring ventilatory support. During the search, an additional 11 reports of postoperative hypercarbia-associated sedation were identified, unrelated to HFNO. In these additional reports an extended duration of severe acute hypercarbia led to sedation or loss of consciousness, consistent with the known effects of hypercarbia on consciousness. These 13 reports highlight the potential dangers of unrecognised and untreated hypercarbia, even if adequate oxygenation is maintained.

Patient-controlled analgesia and oral mucositis pain in hematological malignancies.

Oral mucositis (OM) pain is an anticipated complication of immunosuppressive therapies for hematological malignancies. Opioids are effective for OM-associated pain and dysfunction that is refractory to simple measures. At the study institution, parenteral opioids are preferentially prescribed for the treatment of complicated OM. This audit explores the efficacy of opioids for the management of OM pain using morphine, oxycodone, and fentanyl patient-controlled analgesia (PCA). Pain scores, opioid consumption, resumption of oral intake, and the duration of admission were retrospectively analyzed from patient records over an 18-month period. Two-thirds of included patients had ceased PCA therapy by day 6, by which time there was a meaningful 35.4 percent reduction in pain scores, with very few side effects reported. Interagent comparison demonstrated no significant differences in mean daily pain scores; however, a larger sample size would facilitate an investigation of clinically significant nuances in treatment differences, if they exist.

Management of postsurgical pain in the community.

Following surgery there is often a need for ongoing pain management after the patient is discharged from hospital. This can be made easier if the patient has an appropriate discussion before leaving hospital about what pain they can expect, and they are given a management plan Paracetamol and non-steroidal anti-inflammatory drugs are suitable for most patients. Drugs with a short half-life, such as ibuprofen, may need to be taken regularly Short-acting opioids can have a short-term role, providing guidelines are followed. There is a predictable period of time after surgery when the benefit of an opioid is expected to be maximised before harmful adverse effects will dominate Gabapentinoids are useful for neuropathic pain, but have a limited role in nociceptive pain. Like opioids, they have a risk of misuse The surgeon should be consulted if the patient develops new pain or the postoperative pain becomes more severe Most postsurgical pain will resolve within three months. If not, it is deemed persistent pain that may warrant specialist assessment

Does remifentanil improve ECT seizure quality?

Studies have reported that co-adjuvant remifentanil can enhance electroconvulsive therapy (ECT) seizure quality, putatively by allowing a reduction in the dosage of the main anaesthetic agents, as the latter have anticonvulsant properties. However, whether remifentanil also has direct effects on ECT seizure quality, and by implication, treatment efficacy, is unknown. This is the first study examining the effect of adjuvant remifentanil on ECT seizure quality when the dose of conventional anaesthesia remained unchanged. A total of 96 ECT sessions (from 36 patients) were retrospectively analysed. Subjects received ECT with and without remifentanil (1 µg/kg), while the dose of thiopentone (3-5 mg/kg) or propofol (1-2 mg/kg) was unchanged. Seizure quality indices (time to slow wave activity or TSLOW, amplitude, regularity, stereotypy, post-ictal suppression) and duration were assessed through a structured rating scale by a single trained blinded rater. Linear mixed-effects models with random subject effects analysed the effect of remifentanil on seizure parameters, controlling for other variables that can affect seizure quality or duration. Remifentanil was given in 47.9 % of the ECT sessions. Co-adjuvant remifentanil had no effects on any of the seizure quality parameters analysed [TSLOW (E = -0.21, p > 0.1), amplitude (E = 0.08, p > 0.5), regularity (E = -0.05, p > 0.5), stereotypy (E = -0.02, p > 0.5), suppression (E = -0.3, p > 0.05)] or on seizure duration (E = -0.25, p > 0.1). While adjuvant remifentanil may be a useful strategy for reducing anaesthetic dosage in ECT, present evidence suggests that remifentanil does not have intrinsic properties that enhance ECT seizures.

Which anesthetic agents for ambulatory electro-convulsive therapy?

PURPOSE OF REVIEW: There have been a considerable number of research articles published in the last 10 years outlining possible advances in the provision of electro-convulsive therapy (ECT) anaesthesia. This has resulted in a range of new drugs having been proposed as useful in the ECT setting. In particular, the use of adjuvant drugs that might improve outcomes to treatment has been investigated. RECENT FINDINGS: There is a high level of interest in ketamine and remifentanil as agents that may alter response in ECT anaesthesia, by reducing cognitive effects, and minimizing the dose of induction agent. The numbers of patients involved in current trials have been small, and it is not possible to give a definitive answer as to the usefulness of these drugs at this stage. SUMMARY: This review covers the major recent trials involving new and emerging treatments in ECT, and brings the reader up to date with state of knowledge of ECT anaesthesia and pharmacology.

Novel approach to managing severely labile blood pressure during maintenance electroconvulsive therapy in a man with psychotic depression and Parkinson disease.

Electroconvulsive therapy cannot proceed safely unless blood pressure is within the reference range. Finding the cause of very high or low blood pressure can be very difficult, time consuming, and expensive. We suggest a more valid and reliable time to check blood pressure. This is highlighted in the case of a man that became riddled with iatrogenic complications and needless treatments.

The effect of electrode placement and pulsewidth on asystole and bradycardia during the electroconvulsive therapy stimulus.

Electroconvulsive therapy (ECT) is the most effective treatment for severe depression, and different forms are increasingly used in clinical practice. This study investigated the acute cardiac effects of different forms of ECT: bitemporal and bifrontal (1.5 times seizure threshold), and right unilateral (RUL) (five times seizure threshold). For RUL ECT, the effect of stimulus pulsewidth (1.0 or 0.3 ms) was also examined. Electrocardiograms recorded just prior to and during the ECT stimulus in 476 ECT treatments in 114 patients were examined. The degree of bradycardia (any slowing of heart rate) and incidence of asystole (absence of heart beats for ≥5 s) during the ECT stimulus were measured from these traces. Regression analyses estimated the contribution of patient and ECT treatment factors to the risk of bradycardia and asystole. Bifrontal ECT was associated with less severe bradycardia than bitemporal or RUL ECT (p<0.001). Modelling showed, for a mean pre-ECT heart rate of 85 beats per minute (bpm), expected heart rates during the stimulus were 78 bpm (bifrontal), 46 bpm (bitemporal) and 35 bpm (RUL). Bifrontal ECT was also associated with a lower incidence of asystole than RUL ECT (corrected odds ratio 1:207) and bitemporal ECT (corrected odds ratio 1:24). Ultrabrief pulsewidth stimulation resulted in lesser bradycardia and asystole than standard pulsewidth stimulation for RUL ECT. Modelling showed, for a mean pre-ECT heart rate of 86 bpm, expected heart rates were 43 bpm (ultrabrief RUL) and 26 bpm (RUL). Bradycardia and asystole were relatively common side-effects during the ECT stimulus. Bifrontal ECT was associated with the lowest risk of bradycardia and asystole during ECT and should be considered for patients at risk of arrhythmias and prolonged asystole during ECT.

Augmentation strategies in electroconvulsive therapy.

Electroconvulsive therapy (ECT) is a highly effective treatment, but strategies to enhance therapeutic outcomes are occasionally needed. This review examines the evidence for approaches used for enhancing seizure production: hyperventilation, pretreatment with xanthines, and use of remifentanil or ketamine in ECT anesthesia. Hyperventilation may be a useful strategy to enhance seizure production, but its effects on ECT outcomes have not been systematically studied and require further research. Pretreatment with caffeine, theophylline or aminophylline (xanthines) prolongs the duration of ECT seizures but has not been clearly shown in controlled trials to increase efficacy. Caution is also warranted because their use may be associated with significant adverse effects. There are case reports of the usefulness of remifentanil in assisting seizure induction by reducing the dose of barbiturate anesthetic required, but there are no controlled data on whether it independently enhances efficacy outcomes. Preliminary evidence suggests that ketamine and ECT may have synergistic antidepressant effects, although this needs to be further examined in randomized controlled trials.

Low dose lignocaine added to propofol does not attenuate the response to electroconvulsive therapy.

BACKGROUND: The addition of small amounts of lignocaine (50 mg) to propofol (200 mg) has been previously shown to reduce pain in injection, a common problem with this particular anaesthetic agent. The aim of this study was to investigate whether using the mixture of propofol plus lignocaine had any adverse effects on ECT seizure expression (duration, and ictal quality). METHOD: Ictal EEG records were retrospectively examined in 29 patients who underwent 80 pairs of ECT treatments, one given with propofol alone and one with propofol plus lignocaine. Ictal quality was manually rated for the transition from the polyspike phase to the slow wave phase, amplitude of the mid-ictal spike-and-wave phase, regularity of morphology of the predominant pattern of the slow wave phase, stereotypy, variability of the morphology and amplitude of the slow wave phase and post-ictal suppression. RESULTS: There was no significant difference in seizure duration between the two groups (33.4+/-13.0 s (propofol) vs. 33.6+/-11.2 s (propofol plus lignocaine). Furthermore although the addition of lignocaine delayed the onset of the slow wave phase by about 1s, it resulted in an improvement in three of four of the other measures of ictal quality. CONCLUSION: The addition of a small dose of lignocaine to propofol during ECT treatment enhanced rather than reduced the quality of the seizures produced.

Ketamine and midazolam delivered by patient-controlled analgesia in relieving pain associated with burns dressings.

BACKGROUND: A study involving the use of a mixture of ketamine and midazolam delivered via patient-controlled analgesia (PCA) device was trialed to assess its effectiveness in reducing pain associated with repeated burns dressings in an adult population. METHODS: Patients undergoing burns dressings changes were given a PCA device of ketamine and midazolam to use during the procedure. The aims were to investigate the efficacy of the device and to ascertain what (if any) adverse effects were associated with its use. RESULTS: During the trial period, 44 patients who underwent 95 separate procedures were enrolled. The effectiveness of the device was rated (out of 10) by both staff and patients with the mean scores being 8.47 and 8.50, respectively. In all but 1 case, the proposed procedure was carried out successfully. Thirteen patients reported a total of 23 adverse effects, with hallucinations (11) being the most common. CONCLUSIONS: The use of ketamine/midazolam delivered by PCA was shown to be an effective means of pain control during burns dressings as assessed by both staff and patients. The incidence of adverse events was low.

Cognitive impairment following electroconvulsive therapy--does the choice of anesthetic agent make a difference?

The range of drugs available to provide anesthesia for patients undergoing electroconvulsive therapy (ECT) is ever increasing. Initially, anesthetic agents were selected on the basis of their capacity not to antagonize the induced seizure. This was not always a simple task because almost all general anesthetic agents have "in built" antiepileptic activity. Nonbarbiturate agents such as propofol have been successfully used as alternatives to thiopental and methohexitone, but this drug too has antiepileptic properties. Most recently, opioid-like drugs such as remifentanil have been used, and there has been renewed interest in ketamine, a phencyclidine derivative. Attention has also focused on whether the anesthetic agent selected may affect the cognitive impairment seen after ECT. Studies in this area are limited, but early results suggest that agents such as ketamine may have particular benefit. This article reviews the current literature dealing with anesthesia and postoperative cognitive impairment in general and with regard to ECT in particular.

Supraorbital edema induced by electroconvulsive therapy.

This is a case report of an unusual side effect-unilateral supraorbital edema occurring immediately after electroconvulsive therapy ECT during each treatment occasion-in a depressed patient who was otherwise well. The affected upper eyelid appeared normal before ECT with no history of injury or abnormality. Trauma during ECT, allergic reaction to anesthetic agents, and complications of manual ventilation were found to be unlikely causes. The supraorbital edema occurred as an isolated, benign, complication of ECT and resolved spontaneously.

Effective strategy to guide pathology test ordering in surgical patients.

BACKGROUND: Ordering of pathology testing by junior medical staff is often a haphazard process with little regard to the appropriateness of test ordering. The aim of the present study was to reduce ordering of inappropriate pathology tests in surgical patients attending the pre-admission clinic (PAC) through the introduction of a protocol-based test ordering system and to create an environment where such improvement can be sustained. METHODS: This is a prospective study with a retrospective control group. Three cohorts of patients attending the PAC were included. Group I (n = 700) attended prior to the introduction of the test protocols (April-June 2002) and acted as a control group. Group II (n = 720) attended after the protocol introduction (April-June 2003), and group III (n = 763) attended during the subsequent 3-month period from July to August 2003. The study examined the numbers of patients in each group who were ordered any of eight standard pathology tests. The average number of tests per patient, and cost of tests per patient were also ascertained. RESULTS: Following the introduction of pathology test protocols, the ordering of all but one of the eight tests was statistically significantly reduced. In particular, ordering of coagulation studies was reduced from 22.5% to 13.8% and electrolytes, urea and creatinine from 65.2% to 48.25% of patients (both P < 0.0001). Average number of tests performed per patient declined from 2.48 to 1.88, representing a savings of 10.33 dollars per patient (a decrease from 42.22 dollars to 31.89 dollars) and a projected annualized cost saving in excess of 26,000 dollars. CONCLUSIONS: Provided that certain preliminary guidelines are followed, these protocols can reduce pathology test ordering in any pre-admission Service.

New directions in pain management.

Pain medicine is one of the most rapidly developing medical specialties of today. While there are many modalities that can be used in managing the patient in pain, drug treatment remains, for the most part, the cornerstone of treatment. Opioids retain their position as the foundation of most analgesic strategies, although they tend to be used nowadays in combination with adjuvant analgesics such as paracetamol and nonsteroidal antiinflammatory drugs. The range of available opioids has also been expanded with drugs such as hydromorphone and oxycodone, originally developed almost a century ago. This expanded choice has resulted in the concept of opioid rotation in chronic pain states, an approach that is aimed at maintaining pain control while minimizing adverse effects. Nonsteroidal antiinflammatory drugs continue to play an important role, especially as adjuvants, and the development of drugs such as celecoxib and refecoxib, highly specific for the inhibition of cyclooxygenase 2 pathway has been a further advance. The treatment of neuropathic pain continues to be a challenge to the clinician. While this has traditionally been treated with drugs from the anticonvulsant, antiarrhythmic and anti-depressant groups, results from these treatments have often been less than satisfactory. This has led to the development of completely new drug classes that modulate neuronal transmission in pain pathways, some of which are derived from exotic animal sources, such as the conotoxins from the marine snail family and epibatidine from a species of frog. The role of cannabinoids remains controversial.