Postoperative Nausea and Vomiting: Causes and Treatments

Postoperative Na hirea and Vomiting Ca intakes and TreatmentsPostoperative nausea and emetic is the nausea and be sick symptoms which occurred subsequently a surgery, medicines intake or anaesthesia usage. Around 18 to 30 of operative affected roles live PONV and the nausea and cast symptoms argon usu all in ally self-limiting in most cases.1 Uncomplicated PONV usually firmness within 24 hours after an operation whereas intractable PONV involve different triggering factors and resist to medical manipulation, making it harder to treat. Studies revealed that most perseverings dis same(p) chronic PONV much than operative pain as it is a more distressing sickness and it may widen to several serious clinical consequences if left untreated.In the case of repeated regorge, PONV uncomplainings might suffer from dehydration and have a higher chance of ontogenesis hiatal hernia, a condition where the upper power of stomach protrudes into the thorax through the opening of d iaphragm. an separate(prenominal) than that, tolerants might likewise experience anorexia, gastrointestinal discomfort, headache, weakness, dizziness and nausea while not spue. degenerative retch fannyful likewise cause complications like dental disparage and sore throats due to exposure of oesophageal lining and mouth cavity to the juting age pH gastric acid. Moreover, PONV may induce serious problems like pneumonic aspiration, electrolyte abnormalities, wound dehiscence, increased pain and oesophageal rupture.4,5 Despite causation endurings discomfort, patients also have to pay more for the delayed hospital discharge. Each incidence of egest has increased post anesthetic(a) c ar unit (PACU) stay duration by 20mins. in that respectfore, to wince the unanticipated hospital admission and the financial burden brought by PONV, in that respect is a need to infrastand the disease pathophysiology so that precise and mechanism-based manipulation strategies underside be developed to tackle the emesis problem.The vomiting focus on and the chemo sensory receptor trigger zone (CTZ) are the two principal(prenominal) parts of the virtuoso controlling the vomiting performance. The vomiting centre is located within the in waddescent lamp oblongata and the emesis action is initiated via the stimulation of five primary afferent routes. They are the chemoreceptor trigger zone, vagal mucosal pathway of the gastrointestinal system, neuronal pathways from the vestibular apparatus system, inputs from the periphery glossopharyngeal nerve and reflex afferent pathways from cerebral cortex C2,3 and midbrain afferents. Next, efferent nerve impulses are sent to versatile place of the body such as the pharynx, larynx, diaphragm, intercostals muscles and gut to initiate the vomiting reflex. During the ejection phase of the vomiting reflex, the diaphragm and abdominal musclessimultaneously become and the elevated intra-abdominal pressure leads to the throw u p and expulsion of gastric contents. A variety of receptors are participated in the emesis action. They are the histaminergic(H1), dopaminergic(D2), serotonergic(5-HT3), muscarinic and neurokinin-1 receptors. Consequently, pharmacologic agents which keister on these receptors basis be utilized to treat PONV. However, the British interior(a) Formulary (BNF) had advised that antiemetic agents should only be used erst the fast factor for nausea and vomiting was identified. This is because the use of antiemetic is sometimes dangerous and inappropriate in clinical cases like diabetic ketoacidosis, digoxin or antiepileptic over window glass.6 Hence, the aetiology and possible causative factors of PONV should be investigated to ladder the planning of the pharmaceutical management steps and the antiemetic selection for treating PONV.There are patient-specific factors, surgical factors and anaesthetic put on the line factors which contribute to PONV prevalence. Patients who aged 6 t o 16 year old, female, non-smoker, obese or have a taradiddle of motion sickness or PONV are proven to be the high-risk patient group. Moreover, patients who have chemotherapy, migraine and gastroparesis problems are also susceptible to PONV. Other causative factors include elevated intracranial pressure, metabolic abnormalities, gastroduodenal ulcers, dehydration and infections of the gastroesophageal lining.As for the surgical factors, PONV is related to the premedication side-effect, prolong fasting, conditions of gastric inflation during act ventilation, use of long-acting opioids, nitrous oxide, volatile anaesthetics and high sexually transmitted disease neostigmine in surgery. In addition, frequent head movement of patient and primal intake of food after surgery provide also raise the nausea problem.1 Some types of operations have higher chance of developing PONV, they are the gynaecological surgery, ear, nose and throat operation, intra-abdominal and squint correction surgery. Furthermore, the surgical duration is also an important contributor which predisposes patients to a higher risk of PONV. Every 30 minutes extension in surgical time so-and-so increase risk of PONV by 60% as patient is taking in more anaesthetics into the body. Hence, health care team should control and asperse the surgery duration such that risk of getting PONV is reduced.Although it is not applicable to discuss anaesthetic techniques in this case scenario, it is important to note that regional anaesthesia should be preferred over cosmopolitan anaesthesia during surgical process. According to SOGC guideline, there is an 11-fold increase in the PONV risk when using general anaesthesia rather than regional anaesthesia. Apart from that, volatile anaesthesia, long-acting opioid and neostigmine should also neutralise in surgery as these agents predispose patient to PONV. If the use of general anaesthesia is unavoidable in a surgery, propofol can be a suitable induction agen t because it induces less PONV incidence.A thorough assessment should be carried out to serve as a rationale for the management plan of PONV. The past medical history, frequency and genius of the vomiting episode, blood electrolyte test and physical examination can be evaluated to identify the severity of disease condition and the aetiology of PONV. Subsequently, the appropriate pharmacological agents which bearing on the responsible pathway of emesis can be given.Many antiemetic preparations are available in the market and patients can choose mingled with formulations of solution, buccal tablets, rectal suppository and subcutaneous (SC), intravenous (IV) or intramuscular (IM) injections when oral route is not feasible.6 As no integrity agent provides complete control in emesis, most hospital has take a multimodal approach and a combination strategy where different antiemetics which target on different receptors are utilized in the discourse of PONV.1 combining therapy becomes the preferable way to treat PONV and the generally used combination is 5-HT3 receptor obstructers with droperidol or dexamethasone.Granisetron and ondansetron are examples of 5-HT3 or serotonin receptor antagonists. They exert their effectuate in the chemoreceptor trigger zone and at vagal afferents of the gastrointestinal tract. antecedent studies showed that no single agent performed exceptionally well than the others of same ground level as all 5-HT3 antagonists illustrated similar safety and skill profile. Yet, a new-fashioned meta-analysis which includes 85 randomized controlled, double-blind studies with 15,269 patients involvement had established that the antiemetic effect of granisetron is importantly superior to ondansetron and dolasetron. Ondansetron was also found to be more cost legal than granisetron. 1-2mg of granisetron or 4-8mg of ondansetron can be delivered in intravascular route at the land up of surgery for PONV treatment. Long-acting serotonin antagonis t with higher binding comparison to 5-HT3 receptors, palonosetron, is also available in the market with a long half-life of rough 40 hours. Patients receiving these agents might experience headache, befooling and dizziness problems.Droperidol is a butyrophenone which acts competitively on central dopaminergic receptors in the chemoreceptor trigger zone (CTZ). It is utilise in 0.625-1.25mg IV route at the end of surgery. A regular review of 24 randomized studies was carried out by Schaub and team, they concluded that droperidol decreases PONV incidence regardless of the dose given to patients. However, this drug is only used as a third-line antiemetic for intractable PONV when other alternative treatments failed because droperidol can lead to adverse personal effects associated with QT prolongation and torsades de points, sedation, anxiety, hypotension and extrapyramidal symptoms. Due to its possibility in causing fatal arrhythmia, electrocardiographic monitoring is compulsory each time upon its usage. Nonetheless, a double-blinded randomized clinical study which included 120 patients stated that there was insufficient evidence to prove the QTc prolongation effect induced by droperidol after surgery.Dexamethasone is classified under corticosteroids and often delivered in a 4 to 5mg one-off dose via IV or IM route.19 The exact mechanism of action is unk like a shotn but it is related to the peripheral inhibition of prostaglandin synthesis and its top executive to reduce 5-HT turnover in the CNS. Although dexamethasone is not licensed for the meter reading of PONV, this drug is as effective as other conventional antiemetic drugs like droperidol and serotonin antagonists. A single blinded, randomized-controlled interventional study had illustrated that the administration of dexamethasone is useful for the reduction of PONV episodes (30% in contrast to 70% of the placebo group).20 Moreover, Ormel et al. illustrated that the addition of dexamethasone to dro peridol and ondansetron showed a profound amplification in the efficacy profile of these multiply agents combination. It stands as a good alternative for PONV treatment due to the favour of cost-effectiveness issue and its characteristic of long action duration. As dexamethasone can increase plasma glucose level, it is not recommended for diabetic patient. Furthermore, unfavorable side-effect like postoperative euphoria, impaired wound healing, irritability and adrenal suppression can pass off in patient taking long-term corticosteroids.Metoclopramide is a gastroprokinetic agent which acts on the D2 receptors of the gastrointestinal tract. It can accelerate the gastric emptying rate of gastroparesis and GI obstruction patients.2,6 Despite blocking the D2 receptors, it also has antagonist action on 5-HT3 receptors in the CTZ and vomiting centre when delivered in high doses. 5 to 20mg dose of metoclopramide in subcutaneous, oral or IV route is ordinarily interpreted by patient be fore meal and before bed.6 This medicine is commonly administered as combination therapy because there is conflicting evidence stating that metoclopramide alone is otiose for PONV and it should not be use unless the causative factor for PONV is gastric stasis. Yet, a recent meta-analysis has proved that 10mg IV metoclopramide does well in preventing nausea and vomiting problems after the general anaesthesia surgery. As with the phenothiazines discussed be showtime, both drugs have special use in practice due to the adverse reactions like extrapyramidal effects and dystonia dis say particularly in pediatric and young adults population.Phenothiazines is an example of arduous dopamine antagonist which also act on medullary CTZ. Promethazine, prochlorperazine and perphenazine belong to this group and take part in the prophylaxis and treatment of PONV.24 Prochlorperazine is often administered as a 12.5mg deep intramuscular injection or in a 3 to 6mg dose buccal preparation 12 hourly after the surgery. These agents show superior efficacy in treating opioid-induced PONV. However, high-dose metoclopramide and phenothiazines are now less likely used in clinical practice because of their of import side effects like acute dystonic reactions, sedation, dizziness and extrapyramidal symptoms.9,25 A authoritative analysis consisting of 19 non-randomized and randomized clinical trials had demonstrated that most studies back up the effectiveness of promethazine in reducing PONV occurrence when equald to placebo and that combination therapy is everlastingly preferable and more effective than promethazine alone.Cyclizine is an antihistamine drugs which block the H1 sympathetic pathway in the vomiting centre. The antimuscarinic and antihistamine properties of cyclizine render it to become an antiemetic drug in PONV treatment. A randomised double-blinded study which involved the participations of 960 women had shown that patients who received cyclizine monotherapy showed a slenderly greater antiemetic effect than granisetron alone (PONV incidence of 24% with cyclizine compare to 23% in granisetron group).26 Cyclizine can be given orally, intramuscularly or intravenously, with common antimuscarinic side-effects like sedation and dry mouth. Severe heart also-ran patient should avoid taking this medicine because it leads to detrimental haemodynamic effect.6 The acidic pH of cyclizine at 3.2 also causes pain and irritancy to body upon injection.10 As a upshot, patients usually have 50mg of cyclizine IV injection every 8 hours after proper dilution. A lower dose of 25mg in oral, IM or IV preparations can also be applied in elderly patient.Scopolamine has anticholinergic drug property which inhibits the muscarinic as well as the histaminergic receptors in the vestibular apparatus and the nucleus of the tractus solitarus.3,9 Patients who undergo middle ear surgery or use opioids as postoperative anaesthetics are recommended to take scopolamine for the ir profound efficacy in reducing PONV.3 Scopolamine requires 2 to 4 hours for onset of duration. Hence, a fast-acting antiemetic or a loading bolus dose is needed in urgent case. It is available in transdermal form as a 1.5mg patch which can be placed behind the ear. This slow-release formulation can have sustained effect up to 72 hours. Apfel C et al. had account that transdermal scopolamine had significantly reduced the risk of PONV when compared to the placebo group although it has the main side-effects of dry mouth, sedation and visual disturbances.28 Furthermore, a comparative study between the combination use of ondansetron plus scopolamine patch and ondansetron alone also proved that the earlier group significantly decrease the nausea and vomiting incidence after surgery.Other than a mechanism-based approach, less conventional remediation agents can also be used to treat intractable PONV cases. An antidepressant drug with a novel indication, mirtazapine, is able to ease the nausea and vomiting symptoms because it can antagonize 5-HT3 receptors. A small scale randomized trial which compared the curative outcome of mirtazapine and ondansetron had showed that patients using mirtazapine were less anxious and had fewer PONV episodes than the ondansetron group. Next, olanzapine which is recognized as an atypical antipsychotic drug also proved to have potential in treating PONV. It can inhibit several receptors such as the dopamine, acetylcholine, histamine and 5-HT3 receptors. Ibrahim M et al. had conducted a randomized controlled study which involved 82 surgical patients. The result proved the efficacy and safety profile of olanzapine against PONV especially during the late postoperative stage. Other than medications approach, non-pharmacological interventions also show potential therapeutic efficacy in PONV management.Acupuncture, acustimulation or acupressure serves as a good alternative or adjuvant therapy for PONV patients as it shows good tolerabili ty and safety profile. The P6 point (Neiguan) which located at 5cm near to the ventral wrist is the target site of these alternative approaches. transdermal electrical stimulation delivered to the P6 point of the pericardium meridian has been proved to be an high-octane way in preventing emesis. Patients only complain of light side-effects like needle fainting, allergy, needle site pain, anxiety or lethargy problems when using this method.In order to solve the labour intensive and time-consuming issues of traditional Chinese acupuncture, the acupressure and acustimulation wristband are introduced in the market (Sea-Band and ReliefBand). Sea-Band applies steady, continuous pressure on the P6 point whereas ReliefBand is a watch-like device which conducts low current to P6 point via electrodes in contact with the skin. Based on the well-established efficacy profile and good evidence-base literature support, healthcare professionals can involve more acupuncture interventions in treat ment practice as part of the multimodal approach.In this case, the intractable emesis symptoms experience by the old woman might indicate the reverse of prophylaxis treatment or the need to start a primary antiemetic treatment. forward the initiation of a rescue treatment, a bedside examination and a patient interview should be through to find out whether the PONV symptom is associated to issues such as morphine analgesia, surgical pain management, infection, intestinal obstruction, hypotension, hypoxia, blood in the pharynx, anxiety or removal and insertion of nasogastric tube.5-HT3 antagonist is the recommended drug for patients who antecedently do not receive a prophylaxis treatment. Patient can start with a low dose forage such as ondansetron 1mg, dolasetron 12.5mg and granisetron 0.1mg. If drugs for prophylaxis had been given but fail, patients can then try other class of antiemetics to tackle more diverse receptor pathways. For instance, Habib et al. had found that the fai lure of prophylactic ondansetron or droperidol can be replaced with rescue agents like promethazine (12.5-25 mg IV), prochloperazine (12.5mg IM) or cyclizine (25-50mg IV or IM) to achieve a kick downstairs outcome. This is because consensus guideline support that the repeat use of 5-HT3 antagonist within the initial 6 hours postoperative period provides no extra recovery response. If patient use dexamethasone as prevention agent, small dose 5-HT3 antagonist (25% of prophylactic dose) can then be given as a rescue approach. A study also concluded that the cost-effectiveness of ondansetron in low dose treatment group was higher than that in the high dose prophylatic group.Moreover, in the case of the aggressive treatment failure, such as those who had taken 5-HT3 antagonist, droperidol and dexamethasone altogether but failed, repeat dosing of same prophylactic regimen except dexamethasone can only be considered 6 hours after the surgery though the optimal dosage and timing for readmi nistration still cover unknown. Transdermal scopolamine can also be positive for outpatients as it is a more convenient preparation than the parenteral drugs.Prolong use of opioids for pain control after surgery should also be decrease as side-effects like nausea and vomiting are correlated to the prescribed dose. Alternative analgesics like NSAIDS can be used to substitute the causative opioids. In persisting case, pharmacist can review the prescription and anaesthetic charts to ensure adequate maintenance of analgesia, antiemetic and oxygen supply. Dose escalation under safety and therapeutic dosage range can also be worked on. However, pharmacist should be cautious on polypharmacy problem as it may incense nausea and vomiting in susceptible patient. Non-oral drug preparations can be considered over oral route to avoid burdening of patient with riotous pills at one time. If necessary, the acupuncture treatment can also be applied to attempt a multimodal approach.Pharmacist sh ould also concern approximately the possible dehydration risk that might be encountered by chronic PONV patients. For this reason, the blood pressure, hydration and perfusion level of patients have to be checked on a regular basis. Patients should be told to report of symptoms like dry or ill-chosen mouth, sunken eyes, reduced urination or dark yellow urine. If constipation or diarrhea happens, intravenous fluid replacement therapy, osmotic or stimulant laxative can be given to solve the issues. For the dietetic measures, patients should avoid oily or spicy food which might aggravate the nausea. Small, frequent meal is preferable over big heavy meal as light meal reduce the possibility of gastric discomfort.Patients should be advised to not move around too often to avoid triggering the vomiting centre. Furthermore, in post-discharged nausea and vomiting (PDNV) case, the antiemetic efficacy profiles are different from PONVs as they have dissimilar underlying cause. Droperidol shou ld be avoided as it is ineffective in treating PDNV.2 If the patient still not responsive to all these approaches, specialist intervention should be initiated to treat intractable nausea and vomiting symptoms. Serious causative factors like surgical complication might be suspected and further investigations are required to treat this disease.In a nutshell, the optimization management of PONV disease requires the participation of the multimodal approach. Patients should be treated whence after the accurate disease assessment and further modifications of treatment approaches like (dose-adjustment, introduction of new agents or alternative approaches) can be done to control patients nausea and vomiting symptoms. Lifestyle modification and non-pharmacological interventions also undertake an important part in treating PONV. Proper patient education about symptoms management should be delivered and follow-up session can be position to assess patients rehabilitation progress. Apart from that, reassurance and full supportive care from healthcare teams also play an important role in reducing patient distress and anxiety level.