Clinical and genetic factors associated with post-operative nausea and vomiting after propofol anaesthesia

BACKGROUND

The incidence of post-operative nausea and vomiting (PONV) remains at about 30% despite all therapeutic efforts to reduce it. The clinical risk factors guiding the prophylactic treatment are well established, but genetic factors associated with PONV remain poorly known. The aim of this study was to explore clinical and genetic factors impacting PONV by performing a genome-wide association study (GWAS) together with relevant clinical factors as covariates, and systematically attempt to replicate previously reported PONV associations. Relevant clinical factors are explored with logistic regression model.

METHODS

This was an observational case control study in Helsinki University Hospital between 1 August 2006 and 31 December 2010. One thousand consenting women with elevated risk for PONV, undergoing breast cancer surgery with standardised propofol anaesthesia and antiemetics. After exclusions for clinical reasons and failed genotyping, 815 patients were included with 187 PONV cases and 628 controls. Emergence of PONV up to 7th post-operative day was recorded. PONV at 2-24 h after surgery was selected to be the primary outcome. The GWAS explored associations between PONV and 653 034 genetic variants. Replication attempts included 31 variants in 16 genes.

RESULTS

The overall incidence of PONV up to 7th post-operative day was 35%, where 3% had PONV at 0-2 h and 23% at 2-24 h after surgery. Age, American Society of Anaesthesiologists status, the amount of oxycodone used in the post-anaesthesia care unit, smoking status, previous PONV, and history of motion sickness were statistically significant predictive factors in the logistic model. The receiver operating characteristic-area under the curve of 0.75 (95% CI 0.71-0.79) was calculated for the model. The GWAS identified six variants with suggestive association to PONV (p < 1 × 10-5 ). Of the previously reported variants, association with the DRD2 variant rs18004972 (TaqIA) was replicated (p = .028).

CONCLUSIONS

Our GWAS approach did not identify any high-impact PONV susceptibility variants. The results provide some support for a role of dopamine D2 receptors in PONV.

Transumbilical versus lateral transabdominal removal of benign adnexal masses in laparoscopic surgery-A randomized trial

OBJECTIVE

In laparoscopic adnexal surgery the conventional method of removing a mass from the abdominal cavity in Finland is through a 10-mm-wide lateral abdominal port. The larger the lateral trocar, the greater the risk of pain, complications and delayed recovery. Here, we assumed that adnexal mass removal through a 10-mm umbilical port together with 5-mm side trocars would decrease the postoperative need of analgesics when compared with removal through a 10-mm lateral abdominal port.

STUDY DESIGN

Women scheduled for laparoscopic surgery of a benign adnexal mass were invited to participate. The participants were randomized into two groups: removal via the transumbilical (TU) (n=21) or lateral transabdominal (TA) (n=21) route. General anesthesia and use of local anesthetics were standardized. The amount of postoperative opioid (oxycodone) and visual analog scale (VAS) scores for pain were the primary outcome measures. Secondary outcome measures were nausea/vomiting (VAS evaluation), time to discharge, peri- and postoperative complications, surgeons' opinions of the alternative methods and patients' satisfaction, evaluated via a questionnaire sent six months postoperatively.

RESULTS

There were no significant differences in the use of opioids or median pain-VAS scores between the groups during the first 24h postoperatively. However, in the TU group the amount of women with very low pain-VAS scores (0-1) during the whole 12-h follow-up time was significantly greater than in the TA group (4 vs. 0 women p=0.04). The amounts of nausea and vomiting, and median times to discharge were similar in both groups. There were no major complications.

CONCLUSIONS

Both transumbilical and transabdominal routes of abdominal mass removal during laparoscopy were feasible and safe. However, the transumbilical route resulted in more women with very low pain-VAS scores.

The effective analgesic dose of dexamethasone after laparoscopic hysterectomy

BACKGROUND

Apart from being antiemetic, glucocorticoids have an analgesic property. The optimal dose of dexamethasone in the management of pain after surgery has not been established. In this placebo-controlled, dose-finding study, we evaluated the analgesic effect of three doses of dexamethasone after laparoscopic hysterectomy.

METHODS

We randomized 129 women scheduled for laparoscopic hysterectomy to receive placebo, dexamethasone 5 mg (D5), 10 mg (D10), or 15 mg (D15) IV before the induction of anesthesia. The patients were anesthetized with propofol and remifentanil in a standardized manner. Until the first postoperative morning, postoperative pain was managed with IV oxycodone using patient-controlled analgesia. The visual analog scale scores for pain and side effects, and the amounts of the analgesics were recorded for 3 days after surgery.

RESULTS

The total dose of oxycodone (0-24 h after surgery) was smaller in the D15 (0.34 mg/kg [0.11-0.87]) group than in the placebo group (0.55 mg/kg [0.19-1.13]) (P = 0.003). The doses of oxycodone during Hours 0-2 after surgery were smaller in the D10 (0.17 mg/kg [0.03-0.36]) and D15 (0.17 mg/kg [0.03-0.35]) groups than in the placebo (0.26 mg/kg [0.10-0.48]) (P = 0.001, D10 versus placebo; P < 0.001, D15 versus placebo) group. During Hours 2-24 after surgery, however, the doses of oxycodone were equal in the placebo, D5, D10, and D15 groups (0.31 mg/kg [0.03-0.78], 0.22 mg/kg [0.03-0.92], 0.24 mg/kg [0.05-0.87], and 0.20 mg/kg [0-0.65], respectively). The visual analog scale scores for pain at rest, in motion, or at cough did not differ in the study groups. The incidence of dizziness was lower in the D15 group than in the placebo group (P = 0.001), the D5 group (P = 0.006), and the D10 group (P = 0.030) during the first 24 h after surgery. During the later course of recovery, the incidence of dizziness did not differ among the four study groups.

CONCLUSIONS

IV dexamethasone 15 mg before induction of anesthesia decreases the oxycodone consumption during the first 24 h after laparoscopic hysterectomy. During first 2 h after surgery, dexamethasone 10 mg reduces the oxycodone consumption as effectively as the 15 mg dose.

Ondansetron has similar clinical efficacy against both nausea and vomiting

Ondansetron is widely believed to prevent postoperative vomiting more effectively than nausea. We analysed data from 5161 patients undergoing general anaesthesia who were randomly stratified to receive a combination of six interventions, one of which was 4 mg ondansetron vs placebo. For the purpose of this study a 20% difference in the relative risks for the two outcomes was considered clinically relevant. Nausea was reduced from 38% (969/2585) in the control to 28% (715/2576) in the ondansetron group, corresponding to a relative risk of 0.74, or a relative risk reduction of 26%. Vomiting was reduced from 17% (441/2585) to 11% (293/2576), corresponding to a relative risk of 0.67, or a relative risk reduction of 33%. The relative risks of 0.67 and 0.74 were clinically similar and the difference between them did not reach statistical significance. We thus conclude that ondansetron prevents postoperative nausea and postoperative vomiting equally well.

Influence of the injection site (L2/3 or L3/4) and the posture of the vertebral column on selective spinal anesthesia for ambulatory knee arthroscopy

BACKGROUND

We tested the hypothesis that selective spinal anesthesia for ambulatory knee arthroscopy can be accomplished with a small dose of bupivacaine at the L3/4 interspace with or without a head-down tilt of 5 degrees when the patients were in the lateral decubitus position.

METHODS

In this double-blind study, 123 patients were randomly allocated to receive spinal anesthesia with 4 mg of hyperbaric bupivacaine inserted at either the L2/3 interspace, while the vertebral column was kept horizontal (L2/3 group), or the L3/4 level, with the vertebral column horizontal (L3/4H) or tilted 5 degrees head-down (L3/4T). At 7 min, an additional head down tilt was used in all groups if the sensory block was inadequate.

RESULTS

In the L3/4T group the sensory block (Th8) reached a significantly higher level 30 min after spinal injection, compared with both the L2/3 (Th10) and L3/4H (Th11) groups. In the L3/4H group, 39% of the patients needed an additional tilt for 3 min at 7 min, compared with 10% (P=0.004) in the L3/4T group. Sacral block developed later and recovered faster (P<0.05) in the L3/4T group compared to the L3/4H group. Home-readiness was achieved equally fast in all groups.

CONCLUSION

When producing selective spinal anesthesia, the posture of the vertebral column is a major determinant of both sensory and motor segments to be blocked. A 4-mg dose of hyperbaric bupivacaine at the L3/4 interspace with a 5 degrees head-down tilt of the vertebral column for 6 min is recommended for knee arthroscopy.

A Comparison of Selective Spinal Anesthesia with Hyperbaric Bupivacaine and General Anesthesia with Desflurane for Outpatient Knee Arthroscopy

In this randomized and controlled trial, 64 adult ambulatory knee arthroscopy patients received either selective spinal anesthesia (SSA) with 4 mg of hyperbaric bupivacaine or general anesthesia (GA) with desflurane. We conducted the study to determine whether SSA with small-dose bupivacaine provides equal fast-tracking possibilities, a shorter stay in the postanesthesia care unit, and earlier discharge home compared with GA with desflurane. Patients with a high risk for postoperative nausea and vomiting received prophylaxis in the GA group. No difference was seen in the fast-tracking possibilities or time in the postanesthesia care unit between the groups. Home readiness was achieved after 114 (31-174) and 129 (28-245) min (NS) in the SSA and GA groups, respectively. In the hospital, the pain scores were significantly (P < 0.001) lower in the SSA group compared with the GA group and the need for postoperative opioids was significantly (P = 0.008) larger after GA. The incidence of postoperative nausea and vomiting was 0% versus 19% in the SSA and GA groups (P = 0.024), respectively. We conclude that for outpatients undergoing knee arthroscopy, SSA with hyperbaric bupivacaine provides equal recovery times with less frequent side effects compared with GA with desflurane.

Ondansetron does not prevent pruritus induced by low-dose intrathecal fentanyl

BACKGROUND

Addition of an opioid to low-dose spinal anesthesia with bupivacaine improves the quality and success of anesthesia. However, the intrathecal fentanyl-induced pruritus is as high as 75%. We hypothesized that after administration of 4 or 8 mg of prophylactic IV ondansetron, the incidence of pruritus induced by low-dose intrathecal fentanyl would be significantly lower than after placebo.

METHODS

In this double-blind study, 90 outpatients undergoing knee arthroscopy received 3 mg of bupivacaine + 10 micro g fentanyl intrathecally. Before spinal puncture, the patients received randomly either saline (P) or ondansetron 4 mg (O4) or 8 mg (O8) IV. They were asked about pruritus frequently, and they estimated its severity on a scale of 0-10.

RESULTS

There was no difference in the incidence of pruritus between the three groups: pruritus occurred in 17 (57%), in 21 (75%) and in 19 patients (70%) in P, O4 and O8 groups, respectively. The pruritus was mostly mild. Four patients in the placebo group, three in the O4 and four patients in the O8 groups considered it severe. One patient in each group requested treatment for pruritus; after IV naloxone their pruritus was relieved. Neither time to pruritus nor duration of pruritus differed between the groups. One patient in each group developed a long-lasting (>10 h) pruritus.

CONCLUSIONS

After prophylactic administration of 4 or 8 mg of ondansetron IV, the incidence, duration and severity of pruritus were similar to placebo. Ondansetron does not prevent pruritus induced by low-dose intrathecal fentanyl.

Intrathecal hyperbaric bupivacaine 3 mg + fentanyl 10 microg for outpatient knee arthroscopy with tourniquet

BACKGROUND

Combination of local anesthetic and opioid enables the use of less spinal anesthetic and increases the success of anesthesia. Intrathecal opioid does not prolong motor recovery and thus should not delay discharge home. We hypothesized that 3 mg of hyperbaric bupivacaine with 10 microg of fentanyl permits fast-tracking or shorter stay in post anesthesia care unit (PACU), and earlier discharge home, compared with 4 mg of hyperbaric bupivacaine.

METHODS

In this double-blind study, 100 outpatients undergoing knee arthroscopy received randomly either 4 mg of bupivacaine (B4) or 3 mg of bupivacaine + 10 microg fentanyl (B3F) intrathecally. The volume of 0.8 ml was injected at the L2/3 interspace over a 2-min period. A lateral decubitus position was maintained for 10 min. The sensory block was recorded by using thermal stimuli, and motor block was assessed according to a modified Bromage scale. Fast-tracking criteria were complete recovery of motor block, sensory block Th12 or lower and stable vital signs.

RESULTS

One block (1%) failed. Motor recovery was faster in the B3F group: 60% of the patients recovered in 80 min or less compared with 28% in group B4 (P = 0.002). The PACU-time was shorter: 36 (10-103) vs. 55 (10-140) min, respectively (P = 0.005). Seventeen (B3F) vs. nine patients (B4) could bypass PACU (NS). Time to discharge home was similar in both groups. In the B3F group, 75% of the patients developed pruritus.

CONCLUSION

Both solutions produced reliable spinal anesthesia for outpatient knee arthroscopy. The PACU-time was shorter in the bupivacaine-fentanyl group, but both groups reached home-readiness equally.

Selective spinal anesthesia: a comparison of hyperbaric bupivacaine 4 mg versus 6 mg for outpatient knee arthroscopy

IMPLICATIONS

A low-dose (4 mg), low-volume (0.8 mL), low-flow (2 min) technique with hyperbaric bupivacaine toward the dependent side oriented injection and maintenance of the lateral decubitus position for 10 min produced selective spinal anesthesia with rapid recession of motor block and early discharge home.

Postoperative nausea and vomiting after sevoflurane with or without ondansetron compared with propofol in female patients undergoing breast surgery

IMPLICATIONS

We studied 180 female patients undergoing breast surgery. The patients were randomly allocated to receive one of three anesthetic techniques. Compared with either propofol or sevoflurane alone, sevoflurane with ondansetron resulted in a decreased incidence of postoperative nausea and vomiting. Sevoflurane with ondansetron prophylaxis is a good alternative to propofol with respect to avoiding postoperative nausea and vomiting.