The effect of smoking on postoperative nausea and vomiting

Antiemetic prophylaxis with droperidol in morphine-based intravenous patient-controlled analgesia: a propensity score matched cohort study

BACKGROUND

There are limited real-world data regarding the use of droperidol for antiemetic prophylaxis in intravenous patient-controlled analgesia (IV-PCA). This study aimed to evaluate the antiemetic benefits and sedation effects of droperidol in morphine-based IV-PCA.

METHODS

Patients who underwent major surgery and used morphine-based IV-PCA at a medical center from January 2020 to November 2022 were retrospectively analyzed. The primary outcome was the rate of any postoperative nausea and/or vomiting (PONV) within 72 h after surgery. Propensity score matching was used to match patients with and without the addition of droperidol to IV-PCA infusate in a 1:1 ratio. Multivariable conditional logistic regression models were used to calculate adjusted odds ratios (aORs) with 95% confidence intervals (CIs).

RESULTS

After matching, 1,104 subjects were included for analysis. The addition of droperidol to IV-PCA reduced the risk of PONV (aOR: 0.49, 95% CI: 0.35-0.67, p < 0.0001). The antiemetic effect of droperidol was significant within 36 h after surgery and attenuated thereafter. Droperidol was significantly associated with a lower risk of antiemetic uses (aOR: 0.58, 95% CI: 0.41-0.80, p = 0.0011). The rate of unintentional sedation was comparable between the patients with (9.1%) and without (7.8%; p = 0.4481) the addition of droperidol. Postoperative opioid consumption and numeric rating scale acute pain scores were similar between groups.

CONCLUSIONS

The addition of droperidol to IV-PCA reduced the risk of PONV without increasing opiate consumption or influencing the level of sedation. However, additional prophylactic therapies are needed to prevent late-onset PONV.

Predictors of Postoperative Nausea and Vomiting After Same-Day Surgery: A Retrospective Study

PURPOSE

Postoperative nausea and vomiting (PONV) are main issues after same-day surgery. This study aimed to retrospectively evaluate the electronic medical records of patients who underwent same-day operations under general anesthesia to identify the potential risk factors for PONV.

METHODS

Records of 7759 adult patients who received general anesthesia with remifentanil were reviewed. The patients were assessed for the incidence and severity of PONV. Multiple logistic regression was used to identify risk factors for PONV. A nomogram was established to predict PONV after same-day operations.

FINDINGS

Of 7759 patients, 2317 (29.9%) experienced PONV. In multiple logistic regression analysis, female sex, nonsmoker status, history of motion sickness or nausea, high body mass index (BMI), long surgical duration, laparoscopic procedure, and preoperative analgesic intake within 30 days were independent risk factors for PONV. No correlation was found between the severity of PONV and remifentanil exposure (odds ratio = 1.018; 95% CI, 0.861-1.204; P = 0.834) or remifentanil dose (odds ratio = 1.294; 95% CI, 0.760-2.205; P = 0.343). For the nomogram, which involved sex, laparoscopic procedure, BMI, history of nausea or motion sickness, and analgesic intake within 30 days, the receiver operating characteristic analysis revealed that the AUC values in the training and validation cohorts were 0.81 and 0.83, respectively.

IMPLICATIONS

Predictors for PONV in same-day surgery include female sex, nonsmoker, history of motion sickness or nausea, high BMI, surgical duration >1 hour, laparoscopic procedure, and preoperative analgesic intake within 30 days. A new predictive model is feasible for predicting the incidence of PONV based on the preoperative and intraoperative predictors.

Prevalence and risk factors of post-operative nausea and vomiting in a tertiary-care hospital: A cross-sectional observational study

Background

Post-operative nausea and vomiting (PONV) is an unpleasant and one of the most distressing symptoms for any patient undergoing surgery. The anaesthetist is usually blamed, despite evidence that PONV results from a variety of factors including patient characteristics, anaesthetic techniques, and the type of surgery and post-operative care. This study had been conducted to find out the current prevalence and to assess various risk factors for PONV in the Indian population.

Methods

All patients above 18 years undergoing non-cardiac surgery under anaesthesia were selected from the daily operation theatre list by a systematic random sampling method. Koivuranta score was used to predict PONV in first 24 h post-operatively.

Results

Prevalence of PONV in the study population was found to be 25.6%. There was association detected between female gender, non-smokers and occurrence of PONV (CI 95%, p ≤ 0.001, 0.005, respectively). PONV was seen to be more common in patients with history of PONV in prior surgeries, in patients who underwent surgery under general anaesthesia and in patients where opioids were used in the post-operative period (95% CI, p ≤ 0.001, 0.001 and 0.001 respectively). General, laparoscopic, abdominal, orthopaedic, obstetric, breast and urological surgeries showed a significant association with occurrence of PONV (95% CI, p ≤ 0.05).

Conclusion

Inspite of use of antiemetics (single or dual) being given as part of the institutional protocol, the incidence of PONV was still high. There is a need to update our knowledge regarding newer antiemetics and their inclusion in PONV management guidelines. There is need for further research to study various other possible risk factors which may contribute to occurrence of PONV.

Risk factors for postoperative nausea and vomiting after thoracoscopic pulmonary wedge resection: pitfalls of an increased fentanyl dose

Background

Thoracoscopic pulmonary wedge resection (TPWR) is a surgical procedure that can maintain lung function and is less physically invasive to a patient. However, the risk factors for postoperative nausea and vomiting (PONV) following TPWR remain unknown. We aimed to evaluate multiple risk factors of PONV after TPWR and the impact of PONV on postoperative outcomes.

Methods

We retrospectively reviewed consecutive patients who underwent TPWR for malignant pulmonary tumors at our institution between October 2017 and March 2020. We assessed the differences in the clinical and perioperative parameters between the PONV and non-PONV groups.

Results

We reviewed 160 patients, of whom 27 (16.9%) had PONV. Sixteen (59.3%) patients with PONV required postoperative antiemetics. Failed mobilization was associated with PONV requiring postoperative antiemetics (P=0.048). In the multivariate analysis, increased fentanyl dose was an independent risk factor for PONV (P=0.022). Using the receiver operating characteristic curve, the optimal cut-off value for PONV was 3.58 µg/kg/hr (area under the curve =0.665; sensitivity =85.2%; specificity =53.4%; 95% confidence interval: 0.562–0.768; P=0.007). For example, in a case of a 50-kg patient who underwent a 70-min operation (our median operative time), the total dose of fentanyl within 208 µg was the cut-off value for preventing PONV.

Conclusions

An increased dose of fentanyl/kg/h was the strongest risk factor for PONV during TPWR. The optimal cut-off value for PONV was 3.58 µg/kg/hr. It is important to avoid the inadvertent administration of intraoperative fentanyl.

Effects of smoking on the optimal effect-site concentration of remifentanil required for preventing cough during anesthetic emergence in male patients undergoing laparoscopic or robotic cholecystectomy

Target-controlled infusion of remifentanil is known to reduce cough effectively during emergence from general anesthesia. The effect of smoking on emergence cough remains controversial. Therefore, we aimed to investigate the effect-site concentration (Ce) of remifentanil in the male patients undergoing laparoscopic or robotic cholecystectomy for suppressing emergence cough in smokers and non-smokers.Twenty smokers and 24 non-smokers (sex, male; age range, 20-65 years) were enrolled in this study. Anesthesia was maintained using sevoflurane and remifentanil. The Ce of remifentanil in 50% (EC50) and 95% (EC95) of the patients required for suppressing emergence cough were determined for each group (smokers and non-smokers) using Dixon up-and-down method and isotonic regression method with a bootstrapping approach.Dixon up-and-down method revealed that the EC50 value was significantly higher in smokers (3.51 ± 0.60 ng/mL) than in non-smokers (2.71 ± 0.30 ng/mL) (P < 0.001). In smokers and non-smokers, isotonic regression revealed EC50 to be 4.40 (83% CI, 4.17-4.58) ng/mL and 2.58 (83% CI, 2.31-2.87) ng/mL, respectively, and EC95 to be 4.76 (95% CI, 4.73-4.78) ng/mL and 3.15 (95% CI, 3.04-3.18) ng/mL, respectively.The Ces of remifentanil required to prevent cough during emergence were significantly higher in smokers than in non-smokers. Therefore, clinicians should pay attention to the smoking history of a patient to prevent cough during emergence.

Risk factors of postoperative nausea and vomiting after total hip arthroplasty or total knee arthroplasty: a retrospective study

Background

Postoperative nausea and vomiting (PONV) is a common complication after total hip/knee arthroplasty (THA/TKA) that affects patient satisfaction and postoperative recovery. It has been reported that patients undergoing THA/TKA experience PONV at a frequency of 20–83%. This study investigates the occurrence of PONV in patients and analyzes the risk factors.

Methods

Patients undergoing primary THA/TKA under general anesthesia from October 1, 2017, to May 1, 2018, were included. Data on patient-related factors were collected before THA/TKA. Anesthesia- and surgery-related factors were recorded postoperatively. Risk factors were analyzed using binary logistic regression.

Results

A stronger association of motion sickness and PONV was found at six hours after bilateral THA/TKA [nausea: odds ratio (OR) =14.648, 3.939–54.470; vomiting: OR =8.405, 2.482–28.466]. At 6–24 hours after bilateral THA/TKA, patients who had a history of migraines tended to experience nausea (OR =12.589, 1.978–80.105). Patients with lower body mass index (BMI) were more likely to experience PONV at 24–72 hours (nausea: OR =0.767, 0.616–0.954; vomiting: OR =0.666, 0.450–0.983) after bilateral THA/TKA.

Conclusions

The incidence of PONV after primary bilateral THA/TKA was higher than that after unilateral THA/TKA. The risk factors vary at different time points after surgery, and a history of motion sickness is the most critical factor affecting PONV.

The incidence of postoperative nausea and vomiting after caesarean section in patients with hyperemesis gravidarum: a retrospective cohort study

BACKGROUND

Postoperative nausea and vomiting is one of the most common anaesthetic complications of caesarean section. This study examined the association between hyperemesis gravidarum during pregnancy and nausea and vomiting after caesarean section.

METHODS

A single-centre, retrospective cohort study, using electronic databases of patients with and without hyperemesis gravidarum, undergoing caesarean section from 2015 to 2019. The incidence and severity of postoperative nausea and vomiting were established by a review of the documentation of administration of postoperative anti-emetics within the 24-h period after surgery, and examined using univariable, multivariable binary and ordered logistic regression models.

RESULTS

Data were compared for 76 patients with hyperemesis gravidarum and 315 patients without the condition. The incidence of postoperative nausea and vomiting in the hyperemesis group versus the non-hyperemesis group was 43.4% vs 29.6%, respectively. The odds of experiencing postoperative nausea and vomiting was 1.95 times higher in women with hyperemesis gravidarum than in those without (aOR 1.95, 95% CI 1.13 to 3.36, P=0.016). The odds of having more severe postoperative nausea and vomiting were greater in the hyperemesis gravidarum group (aOR 1.91, 95% CI 1.14 to 3.20, P=0.014).

CONCLUSION

Patients with hyperemesis gravidarum are more likely to develop nausea and vomiting after caesarean section, and this is likely to be of greater severity than in those without the condition. This finding should assist the effective provision of intra-operative and postoperative anti-emetics for patients with hyperemesis gravidarum undergoing caesarean section.

Preoperative Fasting Abbreviation and its Effects on Postoperative Nausea and Vomiting Incidence in Gynecological Surgery Patients

Objective To investigate the effects of preoperative fasting abbreviation with a carbohydrate and protein-enriched solution, on postoperative nausea and vomiting (PONV) incidence in gynecological surgery patients, a population naturally at risk for such unpleasant episodes.

Methods The present prospective double-blind randomized study was performed at The Hospital Municipal e Maternidade Dr. Odelmo Leão Carneiro (HMMOLC, in the Portuguese acronym), in Uberlândia, state of Minas Gerais, Brazil, in partnership with the Gynecology Department of the Universidade Federal de São Paulo (UNIFESP), approved by the Human Research Ethics Committee of UNIFESP and the board of HMMOLC, and included in the Brazil Platform and in the Brazilian Clinical Trial Registry. After signing the consent form, 80 women, who were submitted to gynecological surgery in the period from January to June 2016, were randomized into 2 groups: control group (n = 42) and juice group (n = 38). They received, respectively, 200 mL of inert solution or liquid enriched with carbohydrate and protein 4 hours presurgery. The incidence, frequency and intensity of PONV were studied using the Visual Analogue Scale (VAS), with statistical analysis performed by the software IBM SPSS Statistics for Windows, Version 20.0 (IBM Corp, Armonk, NY, USA).

Results The incidence of nausea and vomiting was lower than in the literature, to this population, with 18.9% (14/74) for the control group and 10.8% (8/74) for the juice group, respectively, with no statistically significant difference between the groups.

Conclusion The incidence of nausea and vomiting was lower than in the literature, but it cannot be said that this is due to the abbreviation of fasting. It can provide greater comfort, with the possibility of PONV prevention in patients at risk for these episodes.

Prediction of intraoperative nausea and vomiting in caesarean delivery under regional anaesthesia

Objectives

This study aimed to predict patients who have caesarean operations under regional anaesthesia and are at risk for intraoperative nausea and vomiting (IONV), for ultimately prompting anaesthetists and surgeons to take preventive measures.

Methods

This was a retrospective study on 209 patients who had caesarean section under spinal-epidural combined regional anaesthesia. The relevant medical history, such as severe nausea and vomiting in the first trimester, smoking, a history of motion sickness, and premenstrual syndrome (PMS), were obtained from the patients’ records and interviews.

Results

Patients who had a female neonate, a history of severe nausea and vomiting in the first trimester, and a history of PMS and motion sickness before pregnancy experienced a significantly higher rate of IONV. Smokers were less susceptible to IONV, but this was not significant.

Conclusion

This study shows that some factors in the medical history of a patient can help identify those who are more likely to suffer from IONV.

Postoperative nausea and vomiting after general anesthesia for oral and maxillofacial surgery

Background

Postoperative nausea and vomiting (PONV) is one of the most common postoperative complications. Despite this, few papers have reported the incidence and independent risk factors associated with PONV in the context of oral and maxillofacial surgery (OMFS). Therefore, we sought to determine the incidence of PONV, as well as to identify risk factors for the condition in patients who had undergone OMFS under general anesthesia.

Methods

A total of 372 patients' charts were reviewed, and the following potential risk factors for PONV were analyzed: age, sex, body mass index, smoking status, history of PONV and/or motion sickness, duration of anesthesia, amount of blood loss, nasogastric tube insertion and retention and postoperative opioid used. Univariate analysis was performed, and variables with a P-value less than 0.1 were entered into a multiple logistic regression analysis, wherein P-values < 0.05 were considered significant.

Results

The overall incidence of PONV was 25.26%. In the multiple logistic regression analysis, the following variables were independent predictors of PONV: age < 30 years, history of PONV and/or motion sickness, and anesthesia duration > 4 h. Furthermore, the number of risk factors was proportional to the incidence of PONV.

Conclusions

The incidence of PONV in patients who have undergone OMFS varies from center to center depending on patient characteristics, as well as on anesthetic and surgical practice. Identifying the independent risk factors for PONV will allow physicians to optimize prophylactic, antiemetic regimens.

Cytochrome P450-mediated drug metabolism in the brain

Cytochrome P450 enzymes (CYPs) metabolize many drugs that act on the central nervous system (CNS), such as antidepressants and antipsychotics; drugs of abuse; endogenous neurochemicals, such as serotonin and dopamine; neurotoxins; and carcinogens. This takes place primarily in the liver, but metabolism can also occur in extrahepatic organs, including the brain. This is important for CNS-acting drugs, as variation in brain CYP-mediated metabolism may be a contributing factor when plasma levels do not predict drug response. This review summarizes the characterization of CYPs in the brain, using examples from the CYP2 subfamily, and discusses sources of variation in brain CYP levels and metabolism. Some recent experiments are described that demonstrate how changes in brain CYP metabolism can influence drug response, toxicity and drug-induced behaviours. Advancing knowledge of brain CYP-mediated metabolism may help us understand why patients respond differently to drugs used in psychiatry and predict risk for psychiatric disorders, including neurodegenerative diseases and substance abuse.

Incidence of and risk factors for postoperative nausea and vomiting at a Japanese Cancer Center: first large-scale study in Japan

Purpose

The first purpose of this study was to determine the incidence of postoperative nausea and/or vomiting (PONV) 0–48 h after anesthesia at a Japanese cancer center. The second purpose of this study was to collect information on PONV risk factors, independently, in the categories of patient-related, anesthesia-related, and surgery-related factors.

Methods

The frequency of nausea and vomiting was prospectively investigated from 0 to 48 h after anesthesia in 1645 patients (11–94 years of age) at a single medical institution. The occurrence of nausea and vomiting and the use of antiemetics were recorded up to 48 h after anesthesia. Patient-related, anesthesia-related, and surgery-related factors were also recorded and submitted to multiple logistic regression analysis to determine the relationship of these factors to nausea and vomiting.

Results

The incidences of nausea and vomiting from 0 to 24 h after anesthesia were 40 and 22 %, respectively. The incidences 24–48 h after anesthesia were 10 and 3 %, respectively. Female sex, previous history of PONV, prolonged anesthesia, and remifentanil use during surgery were identified as risk factors for both nausea and vomiting. The use of a volatile anesthetic, use of fentanyl during surgery, postoperative use of opioids, nonsmoking status, and drinking alcohol on 4 or fewer days per week were identified as risk factors for nausea alone.

Conclusion

The incidence of and risk factors for PONV at a Japanese cancer center according to this study are comparable to those reported elsewhere.

Preoperative evaluation of the surgical patient

A thorough preoperative evaluation to identify correctable medical abnormalities and understand the residual risk is mandatory for all patients undergoing any surgical procedure, including oral surgery. Routine preoperative evaluation will vary among patients, depending on age and general health. This article addresses the preoperative evaluation of surgical patients in general, and the evaluation for general anesthesia in the operating room.

Antiemetic prophylaxis in thyroid surgery: a randomized, double-blind comparison of three 5-HT3 agents

PURPOSE

The aim of this double-blind randomized study was to compare the antiemetic efficacy of three 5-hydroxytryptamine type 3 antagonists in terms of the incidence and intensity of postoperative nausea and vomiting (PONV) in a homogenous group of female patients undergoing thyroidectomy.

METHODS

The study cohort consisted of 203 American Society of Anesthesiologists PS I-II female patients randomized into four groups to receive at induction of anesthesia an intravenous (IV) bolus of 5 ml solution of one of the following: normal saline (placebo), granisetron 3 mg, ondansetron 4 mg, or tropisetron 5 mg. Nausea and vomiting were evaluated at five time points: during the first hour in the postanesthesia care unit (PACU) and 6, 12, 18, and 24 h postoperatively. Nausea intensity was measured using a visual analogue scale score (0-10).

RESULTS

Patients in the placebo group displayed a high incidence of nausea in the PACU and at 6, 12, and 18 h postoperatively (44, 60, 50, and 34%, respectively) and of vomiting (26, 42, 30 and 10%). The administration of granisetron reduced significantly the incidence of nausea at 6, 12, and 18 h (26, 18, and 2%, respectively) and vomiting at 6 and 12 h (10 and 6%, respectively). Ondansetron reduced significantly the incidence of nausea and vomiting only at 6 h postoperatively (28 and 12%, respectively). The administration of tropisetron did not affect the incidence of PONV compared to placebo.

CONCLUSION

Among the female patients of this study undergoing thyroid surgery, granisetron 3 mg provided the best prophylaxis from PONV. Ondansetron 4 mg was equally effective, but its action lasted only 6 h, whereas tropisetron 5 mg was found ineffective.

Drug metabolism within the brain changes drug response: selective manipulation of brain CYP2B alters propofol effects

Drug-metabolizing cytochrome P450 (CYPs) enzymes are expressed in the liver, as well as in extrahepatic tissues such as the brain. Here we show for the first time that drug metabolism by a CYP within the brain, illustrated using CYP2B and the anesthetic propofol (2, 6-diisopropylphenol, Diprivan), can meaningfully alter the pharmacological response to a CNS acting drug. CYP2B is expressed in the brains of animals and humans, and this CYP isoform is able to metabolize centrally acting substrates such as propofol, ecstasy, and serotonin. Rats were given intracerebroventricularly (i.c.v.) injections of vehicle, C8-xanthate, or 8-methoxypsoralen (CYP2B mechanism-based inhibitors) and then tested for sleep time following propofol (80 mg/kg intraperitoneally). Both inhibitors significantly increased sleep-time (1.8- to 2-fold) and brain propofol levels, while having no effect on plasma propofol levels. Seven days of nicotine treatment can induce the expression of brain, but not hepatic, CYP2B, and this induction reduced propofol sleep times by 2.5-fold. This reduction was reversed in a dose-dependent manner by i.c.v. injections of inhibitor. Sleep times correlated with brain (r=0.76, P=0.0009), but not plasma (r=0.24, P=0.39) propofol concentrations. Inhibitor treatments increased brain, but not plasma, propofol levels, and had no effect on hepatic enzyme activity. These data indicate that brain CYP2B can metabolize neuroactive substrates (eg, propofol) and can alter their pharmacological response. This has wider implications for localized CYP-mediated metabolism of drugs, neurotransmitters, and neurotoxins within the brain by this highly variable enzyme family and other CYP subfamilies expressed in the brain.

The effect of smoking nicotine tobacco versus smoking deprivation on motion sickness

BACKGROUND

The experienced smoker maintains adequate nicotine levels by 'puff-by-puff self-control' which also avoids symptomatic nauseating effects of nicotine overdose. It is postulated that there is a varying 'dynamic threshold for nausea' into which motion sickness susceptibility provides an objective toxin-free probe. Hypotheses were that: (i) nicotine promotes motion sickness whereas deprivation protects; and (ii) pleasurable effects of nicotine protect against motion sickness whereas adverse effects of withdrawal have the opposite effect.

METHODS

Twenty-six healthy habitual cigarette smokers (mean ± SD) 15.3 ± 7.6 cigs/day, were exposed to a provocative cross-coupled (coriolis) motion on a turntable, with sequences of 8 head movements every 30s. This continued to the point of moderate nausea. Subjects were tested after either ad-lib normal smoking (SMOKE) or after overnight deprivation (DEPRIV), according to a repeated measures design counter-balanced for order with 1-week interval between tests.

RESULTS

Deprivation from recent smoking was confirmed by objective measures: exhaled carbon monoxide CO was lower (P<0.001) for DEPRIV (8.5 ± 5.6 ppm) versus SMOKE (16.0 ± 6.3 ppm); resting heart rate was lower (P<0.001) for DEPRIV (67.9 ± 8.4 bpm) versus SMOKE (74.3 ± 9.5 bpm). Mean ± SD sequences of head movements tolerated to achieve moderate nausea were more (P = 0.014) for DEPRIV (21.3 ± 9.9) versus SMOKE (18.3 ± 8.5).

DISCUSSION

Tolerance to motion sickness was aided by short-term smoking deprivation, supporting Hypothesis (i) but not Hypothesis (ii). The effect was was approximately equivalent to half of the effect of an anti-motion sickness drug. Temporary nicotine withdrawal peri-operatively may explain why smokers have reduced risk for postoperative nausea and vomiting (PONV).

Brain drug-metabolizing cytochrome P450 enzymes are active in vivo, demonstrated by mechanism-based enzyme inhibition

Individuals vary in their response to centrally acting drugs, and this is not always predicted by drug plasma levels. Central metabolism by brain cytochromes P450 (CYPs) may contribute to interindividual variation in response to drugs. Brain CYPs have unique regional and cell-type expression and induction patterns, and they are regulated independently of their hepatic isoforms. In vitro, these enzymes can metabolize endogenous and xenobiotic substrates including centrally acting drugs, but there is no evidence to date of their in vivo function. This has been difficult to demonstrate in the presence of hepatically derived metabolites that may cross the blood-brain barrier. In addition, because of the membrane location of brain CYPs and the rate limiting effect of endogenous heme levels on the activity and appropriate membrane insertion of some induced CYPs, it has been unclear whether sufficient cofactors and coenzymes are present for constitutive and induced CYP forms to be enzymatically active. We have developed a method using a radiolabeled mechanism-based inhibitor of CYP2B1, (3)H-8-methoxypsoralen, to demonstrate for the first time that both the constitutive and induced forms of this enzyme are active in situ in the living rat brain. This methodology provides a novel approach to assess the function of enzymes in extrahepatic tissues, where expression levels are often low. Selective induction of metabolically active drug metabolizing enzymes in the brain may also provide ways to control prodrug activation in specific brain regions as a novel therapeutic avenue.

Nicotine patch for the prevention of postoperative nausea and vomiting: a prospective randomised trial

BACKGROUND AND OBJECTIVE

It has been demonstrated that smoking significantly reduces postoperative nausea and vomiting (PONV). However, there are approximately 4000 substances in cigarette smoke that can be responsible for this effect. To demonstrate whether nicotine is the substance with antiemetic effects we applied a nicotine patch in patients undergoing laparoscopic cholecystectomy under general anaesthesia.

METHODS

Seventy-five patients classified as ASA (American Society of Anesthesiologists' classification) I/II were divided in three groups: group 1 (n = 25), which comprised non-smokers; group 2 (n = 25), which comprised patients who had given up smoking for the last 5 years and received perioperatively a nicotine patch that contained 16.6mg nicotine/patch; and group 3 (n = 25), which comprised actual smokers. Postoperatively, the incidence of PONV and the need for antiemetic rescue medication were monitored every 6 hours.

RESULTS

We found a significant reduction in the incidence of PONV in group 2 (5/25 [20%], p = 0.0001 vs group 1) and group 3 (8/25 [32%], p = 0.002 vs group 1) compared with group 1 (18/25 [76%]). The difference in incidence of PONV between group 2 and group 3 was not significant (p > 0.05).

CONCLUSIONS

Nicotine significantly reduced the incidence of PONV after laparoscopic cholecystectomy.

Management of outpatient ear, nose and throat surgery

In the year under review there have been steady advances in anaesthesia. Premedication in children is best achieved with oral midazolam formulated in flavoured syrups, and the inhalational induction of anaesthesia may be accomplished using sevoflurane. Pain management of the most common surgical procedure performed in children, tonsillectomy/adenoidectomy, is still sub-optimal, but combinations of opioids and non-steroidal anti-inflammatory drugs are helpful. There are, however, some concerns regarding the possible increases in postoperative blood loss after tonsillectomy when non-steroidal anti-inflammatory drugs are used. Middle ear surgery leads to a high incidence of postoperative nausea and vomiting, and these are best managed by utilizing a total intravenous anaesthetic technique with propofol, the avoidance of nitrous oxide, and administration of dexamethasone and a 5-hydroxytryptamine receptor antagonist such as ondansetron.

Tobacco control for anesthesiologists

Anesthesiologists daily witness the consequences of tobacco use, the most common preventable cause of death. Smoking-related diseases such as atherosclerosis and chronic obstructive pulmonary disease increase anesthetic risk, and even smokers without overt disease are at increased risk for morbidity such as pulmonary and wound-related complications. Evidence suggests that stopping smoking will reduce the frequency of these complications. Nicotine and the other constituents of cigarette smoke, such as carbon monoxide, have important physiologic effects that may affect perioperative management. In addition, it is now apparent that the scheduling of elective surgery represents an excellent opportunity for smokers to quit in the long term. This review serves as an introduction to tobacco control for anesthesiologists, first examining issues of importance to perioperative management. It then discusses how anesthesiologists and other perioperative physicians can help address tobacco use, both at an individual level with their patients, and by contributing to the implementation of effective public health strategies in their countries. Anesthesiologists can play a key role in helping their patients quit smoking. Effective tobacco control measures applied to surgical patients will not only improve immediate perioperative outcomes but also long-term health.

Identification of risk factors for postoperative nausea and vomiting in the perianesthesia adult patient

Postoperative nausea and vomiting (PONV) is a common and potentially debilitating complication of surgery. The preoperative assessment of PONV using established risk assessment tools enables the identification of patients at risk and potentially decreases the incidence of PONV in adult surgical patients. The identification of risk factors associated with PONV and the factors that are independent predictors of PONV preoperatively can facilitate the effective prophylactic treatment and management of PONV in adult surgical patients.

Effects of preoperative smoking cessation on the incidence and risk of intraoperative and postoperative complications in adult smokers: a systematic review

OBJECTIVES

To establish the effect of preoperative smoking cessation on the risk of postoperative complications, and to identify the effect of the timing of preoperative cessation.

DATA SOURCES

The Cochrane Library Database, PsycINFO, EMBASE, Medline, and CINAHL databases were searched, using the terms: "smoking", "smoking-cessation", "tobacco-use", "tobacco-abstinence", "cigarett$", "complication$", "postoperative-complication$", "preoperative", "perioperative" and "surg$". Further articles were obtained from reference lists. The search was limited to articles on adults, written in English and published up to November 2005.

STUDY SELECTION

Prospective cohort designs exploring the effects of preoperative smoking cessation on postoperative complications were included. Two reviewers independently scanned abstracts of relevant articles to determine eligibility. Lack of agreement was resolved through discussion and consensus. Twelve studies met the inclusion criteria.

DATA EXTRACTION

Methodological quality was assessed by both reviewers, exploring validation of smoking status, clear definition of the period of smoking cessation, control for confounding variables and length of follow-up.

DATA SYNTHESIS

Only four of the studies specified the exact period of smoking cessation, with six studies specifying the length of the follow-up period. Five studies revealed a lower risk or incidence of postoperative complications in past smokers than current smokers or reported that there was no significant difference between past smokers and non-smokers.

CONCLUSIONS

Longer periods of smoking cessation appear to be more effective in reducing the incidence/risk of postoperative complications; there was no increased risk in postoperative complications from short term cessation. An optimal period of preoperative smoking cessation could not be identified from the available evidence.

Postoperative nausea and vomiting (PONV) after orthognathic surgery: a retrospective study and literature review

PURPOSE

Postoperative nausea and vomiting (PONV) is the most common postoperative complication after surgery and general anesthesia. PONV occurs primarily within the first 24 hours and can lead to significant morbidity, delayed hospital discharge, increased hospital costs and perhaps most importantly, poor patient satisfaction. We sought, in this study, to determine the prevalence of PONV and to identify risk factors in patients who underwent orthognathic surgery.

PATIENTS AND METHODS

We conducted a retrospective cross-sectional analytic survey of 553 consecutive patients over 14 years of age, who underwent maxillary and/or mandibular osteotomies at Kaiser Permanente Hospital (Oakland, CA), between January 2003 and March 2004. Patient-, anesthesia- and surgery-related factors that were considered to have a possible effect on the prevalence of PONV events were evaluated.

RESULTS

A total of 514 patients met the inclusion criteria. Among these patients, 40.08% experienced PONV during the first 24 hours after surgery. The most important predictive factors associated with an increased risk of PONV were female gender, young patients (15 to 25 years old), nonsmoking status, presence of predisposing factors (ie, prior history of motion sickness and/or PONV, vertigo or migraine headaches), use of volatile general anesthetics, maxillary surgery, postoperative pain level (PACU) and the use of postoperative analgesic opioid drugs. We found a directly proportional relationship between the number of risk factors and the prevalence of PONV.

CONCLUSION

We found PONV had a high prevalence among patients undergoing orthognathic surgery. Further studies are needed to develop effective protocols for preventing this common and unpleasant problem.

Risk factors for nausea and vomiting following vitrectomy in adults

BACKGROUND AND OBJECTIVE

Postoperative nausea and vomiting (PONV) after ophthalmic surgery under general anaesthesia remains a complex and perturbing complication associated with several factors. Little information is available regarding the risk factors for nausea and vomiting after vitrectomy in adults. In this study, we evaluated the potential risk factors for PONV after vitrectomy in adult patients.

METHODS

Univariate and multivariate analyses of clinical factors associated with PONV were undertaken in a retrospective case-control series of 247 adult patients undergoing vitrectomy under general anaesthesia. We examined PONV for the first 48 h. Factors examined were age, body mass index (BMI), smoking status, H2-blocker as premedication, type of general anaesthesia (sevoflurane and fentanyl or total intravenous (i.v.) anaesthesia with propofol and fentanyl), duration of surgery, and intraoperative fentanyl dose.

RESULTS

Fifty-nine patients (24%) reported one or more episodes of PONV during the study period. Female gender (P < 0.01), lower BMI (P < 0.01) and general anaesthesia with inhalational anaesthetics (P < 0.01) were significantly related to nausea during the first 2 h postoperatively. Female gender (P < 0.01) was significantly related to nausea and vomiting throughout the study period. Other factors, including smoking status, did not alter the risk for nausea and/or vomiting.

CONCLUSIONS

We conclude that female gender, lower BMI and inhalation anaesthesia are the main risk factors for PONV after vitrectomy in adults. Smoking status did not reduce the incidence of PONV in our patients.

Recent smoking behavior and postoperative nausea and vomiting

The risk of postoperative nausea and vomiting (PONV) is reduced in cigarette smokers by unknown mechanisms. If protection is related to an acute effect of smoke constituents, smokers with the most recent exposure to cigarette smoke would be most protected. We tested the hypothesis that in cigarette smokers, postoperative nausea is correlated with recent exposure to cigarette smoke as quantified by exhaled carbon monoxide (CO) concentrations. In this observational study, exhaled CO levels were measured in 140 female smokers preoperatively. PONV was assessed over the first 24 h after surgery. There was no correlation (assessed with Spearman rank correlation) between preoperative CO and nausea scores at recovery room discharge. Significant correlations were found between nausea assessed over the first 24 h postoperatively and a history of PONV or motion sickness, the use of intraoperative antiemetic prophylaxis, duration of anesthesia, and use of opioids in the postanesthesia care unit. However, there was no correlation between preoperative CO and nausea over the first 24 h. These preliminary data suggest that the effect of smoking in reduced PONV is not directly related to preoperative exhaled CO levels.

Risk Factors for Postoperative Nausea and Vomiting

Knowledge of postoperative nausea and vomiting (PONV) risk factors allows anesthesiologists to optimize the use of prophylactic regimens. Modern PONV risk research began in the 1990s with publication of studies using logistic regression analysis to simultaneously identify multiple independent PONV predictors and publication of meta-analyses and systematic reviews. This literature shows that female gender post-puberty, nonsmoking status, history of PONV or motion sickness, childhood after infancy and younger adulthood, increasing duration of surgery, and use of volatile anesthetics, nitrous oxide, large-dose neostigmine, or intraoperative or postoperative opioids are well established PONV risk factors. Possible risk factors include history of migraine, history of PONV or motion sickness in a child's parent or sibling, better ASA physical status, intense preoperative anxiety, certain ethnicities or surgery types, decreased perioperative fluids, crystalloid versus colloid administration, increasing duration of anesthesia, general versus regional anesthesia or sedation, balanced versus total IV anesthesia, and use of longer-acting versus shorter-acting opioids. Early-phase menstruation, obesity and lack of supplemental oxygen are disproved risk factors. Current risk scoring systems have approximately 55%-80% accuracy in predicting which patient groups will suffer PONV. Further research examining genetic and under-investigated clinical patient characteristics as potential risk factors, and involving outpatients and children, should improve predictive systems.

CYP2B6 is expressed in African Green monkey brain and is induced by chronic nicotine treatment

CYP2B6 is a drug-metabolizing enzyme expressed in human tissues that can activate bupropion (a smoking cessation drug) and tobacco smoke nitrosamines and can inactivate drugs such as nicotine. Smokers have higher brain CYP2B6 protein levels compared to non-smokers but the cause of this elevation is unknown. We investigated the basal expression and the effect of chronic nicotine treatment on CYP2B6 protein in African Green monkey (Cercopithecus aethiops) brain. Basal expression of brain CYP2B6 was strong in specific cells such as the frontal cortical pyramidal cells, the cerebellar Purkinje cells and the neurons in the substantia nigra. Basal CYP2B6 protein levels varied 2.7-fold (non-significant) among 12 brain regions. All monkeys were given a subcutaneous 0.1 mg/kg nicotine test dose prior to treatment and the maximum plasma concentration achieved was 87 +/- 69 ng/ml and the half-life was 2.6 +/- 1.5 h. Monkeys were treated subcutaneously twice daily with nicotine at 0.05 mg/kg for 2 days, 0.15 mg/kg for 2 days followed by 0.3 mg/kg for 18 days (n = 6) or saline (n = 6). Chronic nicotine treatment induced CYP2B6 expression in specific cells such as astrocytes and neurons in the frontal cortex, caudate, thalamus and hippocampus. CYP2B6 protein levels were induced 1.5-fold in the frontal cortex (p < 0.01). Hepatic CYP2B6 expression was not altered by nicotine. In conclusion, CYP2B6 protein is expressed in specific cells in monkey brain and is induced by chronic nicotine treatment which may impact central metabolism of CYP2B6 substrates such as bupropion and nicotine.

A korean predictive model for postoperative nausea and vomiting

Postoperative nausea and vomiting (PONV) is one of the most common and distressing complications after surgery. An identification of risk factors associated with PONV would make it easier to select specific patients for effective antiemetic therapy. We designed a case-controlled study to identify the risk factors for PONV in 5,272 surgical patients. At postoperative 2 and 24 hr, patients were visited and interviewed on the presence and severity of PONV. Thirty nine percent of patients experienced one or more episodes of nausea or vomiting. Five risk factors were highly predictive of PONV: 1) female, 2) history of previous PONV or motion sickness, 3) duration of anesthesia more than 1 hour, 4) non-smoking status, and 5) use of opioid in the form of patient controlled analgesia (PCA), in the order of relevance. The formula to calculate the probability of PONV using the multiple regression analysis was as follows: P (probability of PONV)=1/1+e(-Z), Z=-1.885+0.894 (gender)+0.661 (history)+0.584 (duration of anesthesia)+0.196 (smoking status)+0.186 (use of PCA-based opioid) where gender: female=1, male=0; history of previous PONV or motion sickness: yes=1, no=0; duration of anesthesia:more than 1 hr=1, less than or 1 hr=0; smoking status: no=1, yes=0; use of PCA-based opioid: yes=1, no=0.

Postoperative nausea and vomiting in patients undergoing total abdominal hysterectomy under spinal anaesthesia: a randomized study of ondansetron prophylaxis

BACKGROUND AND OBJECTIVE

Patients undergoing total abdominal hysterectomy under general anaesthesia have a high risk of developing postoperative nausea and vomiting (PONV). The aim of this study was to evaluate the incidence of PONV in patients undergoing total abdominal hysterectomy under spinal anaesthesia with intravenous patient-controlled analgesia (PCA) using morphine and to compare its incidence with and without antiemetic prophylaxis.

METHODS

Thirty-four patients undergoing total abdominal hysterectomy under spinal anaesthesia with i.v. PCA morphine postoperatively were divided into two groups. The first (n = 17) received ondansetron prophylaxis near the end of surgery while the second (n = 17) received no prophylaxis. Morphine consumption, emetic episodes (on a 3-point scale), patient satisfaction (visual analogue score), sedation and pruritus were evaluated 2, 4, 6, 9, 12, 18 and 24h postoperatively.

RESULTS

Patient characteristics, postoperative morphine consumption (43.3 +/- 7.6 vs. 40.3 +/- 12.3 mg) and peristaltic recovery time (16.9 +/- 5 vs. 18.4 +/- 5.2 h) were similar in both groups. Overall nausea and vomiting were significantly lower in the ondansetron prophylaxis group than in the group without prophylaxis (52.9% vs. 88.2%, P < 0.05). Though nausea alone was higher in the prophylaxis group (41.2% vs. 29.4%), nausea with vomiting was significantly lower in the prophylaxis group (11.8% vs. 58.8%, P < 0.01). Patients' satisfaction scores were higher in the ondansetron group at all times and the difference was significant (P < 0.05) 4 h postoperatively.

CONCLUSIONS

The incidence of PONV in patients undergoing total abdominal hysterectomy under spinal anaesthesia with i.v. PCA morphine is very high (88.2%). Antiemetic prophylaxis with ondansetron is highly recommended in this patients group resulting in a lower incidence of nausea and vomiting, and significantly improves patient' satisfaction and life quality in the early postoperative period.

Das präoperative „Rauchverbot“

For decades it has been assumed, that smoking within 6 hours of anesthesia and surgery raises the incidence of perioperative cardiopulmonary complications (PPC) including aspiration. Therefore, every patient is advised to stop smoking at the day before surgery, and not to smoke at all at the day of surgery. If the patient does not follow this advice, this will result in a postponement of anesthesia and surgery. The present article aims at re-investigating the scientific basis of this dogma in anesthesia, which virtually forbids smoking at short-term prior to surgery. The influence of short-term (6 h) abstinence from smoking on the perioperative pulmonary morbidity has not been systematically investigated. Interestingly, giving up smoking less than two months prior to surgery does not significantly decrease, but rather may increase the incidence of PPC. With respect to the risk of aspiration, smoking does not increase either the volume or the acidity of gastric juices. A short-lived reduction in the tone of the lower esophageal sphincter is reversible within minutes after termination of smoking. While the emptying of liquid gastric juices is not influenced by smoking, there is a certain delay in the propulgation of solid food. This effect, however, is probably of no clinical relevance in patients, who had their last solid meal the evening before surgery. Hence, we conclude that the anesthesia dogma, which rules out smoking shortly prior to anesthesia, cannot be based on an otherwise increased incidence of pulmonary aspiration or other pulmonary morbidity. However, acute smoking (probably by an increase in COHb) may increase the incidence of myocardial ischemia during exercise and anesthesia. With reference to this possible cardiac complication it still seems reasonable to discourage smoking at least 12 to 48 hours prior to surgery in patients with elevated cardiac risk.

An audit of post-operative nausea and vomiting, following cardiac surgery: scope of the problem

Post-operative nausea and vomiting is a major problem for patients following cardiac surgery. The literature in this area identifies that there are a number of individual patient and post-operative factors which increase the risk of post-operative nausea and vomiting, including female gender, non-smoker, age, use of opioids, pain and anxiety. An audit involving 200 patients, who had undergone cardiac surgery was implemented to assess/evaluate the incidence of nausea and vomiting for this patient group. Data collected included information relating to nausea and vomiting, pain, consumption of morphine and other individual patient variables. The results suggest that nausea and vomiting, is experienced by a large number of patients after cardiac surgery (67%), with the majority suffering on the first day after surgery. The duration of nausea and vomiting for most is short, but for a significant number (7%) it can last up to one-quarter of their initial post-operative course. The paper discusses key implications for practice arising from this project.