Modified paediatric preoperative risk prediction score to predict postoperative ICU admission in children: a retrospective cohort study

OBJECTIVE

To integrate intrinsic surgical risk into the paediatric preoperative risk prediction score (PRPS) model to construct a more comprehensive risk scoring system (modified PRPS) and improve the prediction accuracy of postoperative intensive care unit (ICU) admission in paediatric patients.

DESIGN

This was a retrospective study conducted between 1 January and 30 December 2016. Data on age, American Society of Anaesthesiology physical status (ASA-PS), oxygen saturation, prematurity, non-fasted status, severity of surgery and immediate transfer to the ICU after surgery were collected. The modified PRPS was developed by logistic regression in the derivation cohort; it was tested and compared with the paediatric PRPS and ASA-PS by the Hosmer-Lemeshow test, the receiver operating characteristic (ROC) curve and Kappa analysis in the validation cohort.

SETTING

Hospital-based study in China.

PARTICIPANTS

Paediatric patients (≤14 years) who underwent surgery under general anaesthesia were included, and those who needed reoperation due to surgical complications or stayed in the ICU preoperatively were excluded.

MAIN OUTCOME MEASURE

ICU admission rate, defined as any patients' direct disposition from the operating room to the ICU immediately after the surgery.

RESULTS

A total of 9261 paediatric patients were included in this study, with 418 patients admitted to the ICU. In the validation cohort, the modified PRPS model fit the test data well (deciles of risk goodness-of-fit χ²=6.84, p=0.077). The area under the ROC curve of the modified PRPS, paediatric PRPS and ASA-PS were 0.963, 0.941 and 0.870, respectively (p<0.05), and the Kappa values were 0.620, 0.286 and 0.267. Analyses in the cohort indicated that the modified PRPS was superior to the paediatric PRPS and ASA-PS.

CONCLUSIONS

The modified PRPS integrating intrinsic surgical risk shows better prediction accuracy than the previous PRPS.

Warming efficacy of Ranger™ and FT2800 fluid warmer under different room temperatures and flow rates

The comparison of the heating capabilities with different warming system between 3M™ Ranger™ warmer (3M) and FT2800 fluid warmer (FT) under different room temperatures and infusion rates, has been rarely reported previously. The study was then aimed to compare the warming efficacies of dry heat technology (3M) and coaxial warming system (FT) under different room temperatures and infusion rates, the advantages and disadvantages of both infusion systems would be compared to provide reference for clinical infusion practice. In the study, both target warming temperatures of 3M and FT warmer were set at 41 °C, fluid was administrated under 20, 22 and 24 °C room temperatures and drip rates of 60, 80, 100, 120, 140, 160, 200, 350 drops min^-1. The fluid temperature at the outlet of the infusion tube (T_outlet) was measured and compared. The T_outlet of FT was higher than that of 3 M (P < 0.001) under different room temperatures. The T_outlet of FT increased with the room temperature raised (P < 0.05). As for 3M, T_outlet was lowest at 20 °C (P < 0.001) and no statistical difference of T_outlet was found between 22 and 24 °C (P = 0.667). Linear regression showed that the T_outlet of 3M increased with the speed up of drip rate, while the T_outlet of FT was decreased. The relationship between T_outlet & room temperature & drip rate for both 3M and FT warmers was calculated by a formula. 3M Ranger™ and FT2800 show different heating capabilities under different room temperatures and drip rates. 3M is more efficient at high flow rate while FT is more efficient at low flow rate. There is a formula relationship between T_outlet & room temperature & drip rate for both 3M and FT warmers.

Analyzing Electroencephalography (EEG) Waves Provides a Reliable Tool to Assess the Depth of Sevoflurane Anesthesia in Pediatric Patients

BACKGROUND Studies have reported that BIS is unreliable in children because its algorithm provides misleading information about the actual depth of anesthesia. Raw EEG analysis provides direct neurophysiologic measurement of cerebral activity. The relationship between age and EEG has rarely been reported, thus the aim of the present study was to compare raw electroencephalography (EEG) among different age groups of surgical patients under general anesthesia with 1.0 MAC sevoflurane. MATERIAL AND METHODS We enrolled 135 patients aged 0-80 years old (ASA physical status I or II) undergoing surgery, who were divided into 6 groups: 1-12 months old (group 1), 1-3 years old (group 2), 3-6 years old (group 3), 6-18 years old (group 4), 18-65 years old (group 5), and 65-80 years old (group 6). Different raw EEG waves (alpha, delta, and theta) were compared for all subjects. RESULTS The BIS values in groups 1 to 6 were 52.2±12.7, 55.0±8.0, 44.5±7.3, 43.8±7.3, 44.2±6.2, and 49.1±6.2 respectively. Compared with groups 1 and 2 (52.2±12.7, 55.0±8.0), BIS values of groups 3, 4, and 5 (44.5±7.3, 43.8±7.3, 44.2±6.2, respectively) were lower (P<0.05). Theta frequency was observed in the 6 groups. The EEG frequencies in groups 1 to 6 were 6.0 (5.5-6.0), 6.0 (5.5-6.0), 6.0 (5.5-6.0), 6.0 (6.0-7.0), 6.3 (6.0-7.0), and 6.0 (5.1-6.0), respectively. Compared with group 6, EEG frequencies in groups 4 and 5 were higher (P<0.05). BIS value was significantly correlated with EEG frequency (R²=0.063, P<0.01). CONCLUSIONS Analyzing raw EEG waves provides more accurate judgement of depth of anesthesia, especially in pediatric cases in which monitors often provide misleading values.

Intravenous dexmedetomidine pre-medication reduces the required minimum alveolar concentration of sevoflurane for smooth tracheal extubation in anesthetized children: a randomized clinical trial

Background

It has been known that Dexmedetomidine pre-medication enhances the effects of volatile anesthetics, reduces the need of sevoflurane, and facilitates smooth extubation in anesthetized children. This present study was designed to determine the effects of different doses of intravenous dexmedetomidine pre-medication on minimum alveolar concentration of sevoflurane for smooth tracheal extubation (MAC_EX) in anesthetized children.

Methods

A total of seventy-five pediatric patients, aged 3–7 years, ASA physical status I and II, and undergoing tonsillectomy were randomized to receive intravenous saline (Group D₀), dexmedetomidine 1 μg∙kg⁻¹ (Group D₁), or dexmedetomidine 2 μg∙kg⁻¹ (Group D₂) approximately 10 min before anesthesia start. Sevoflurane was used for anesthesia induction and anesthesia maintenance. At the end of surgery, the initial concentration of sevoflurane for smooth tracheal extubation was determined according to the modified Dixon’s “up-and-down” method. The starting sevoflurane for the first patient was 1.5% in Group D₀, 1.0% in Group D₁, and 0.8% in Group D₂, with subsequent 0.1% up or down in next patient based on whether smooth extubation had been achieved or not in current patient. The endotreacheal tube was removed after the predetermined concentration had been maintained constant for ten minutes. All responses (“smooth” or “not smooth”) to tracheal extubation and respiratory complications were assessed.

Results

MAC_EX values of sevoflurane in Group D₂ (0.51 ± 0.13%) was significantly lower than in Group D₁ (0.83 ± 0.10%; P < 0.001), the latter being significantly lower than in Group D₀ (1.40 ± 0.12%; P < 0.001). EC₉₅ values of sevoflurane were 0.83%, 1.07%, and 1.73% in Group D₂, Group D₁, and Group D₀, respectively. No patient in the current study had laryngospasm.

Conclusion

Dexmedetomidine decreased the required MAC_EX values of sevoflurane to achieve smooth extubation in a dose-dependent manner. Intravenous dexmedetomidine 1 μg∙kg⁻¹ and 2 μg∙kg⁻¹ pre-medication decreased MAC_EX by 41% and 64%, respectively.

Trial registration

Chinese Clinical Trial Registry (ChiCTR): ChiCTR-IOD-17011601, date of registration: 09 Jun 2017, retrospectively registered.

The efficacy and safety of mivacurium in pediatric patients

Background

Mivacurium is the shortest acting nondepolarizing muscle relaxant currently available; however, the effect of different dosages and injection times of intravenous mivacurium administration in children of different ages has rarely been reported. This study was aimed to evaluate the muscle relaxant effects and safety of different mivacurium dosages administered over different injection times in pediatric patients.

Methods

Six hundred forty cases of pediatric patients, aged 2 m-14 years, ASA I or II, were divided into four groups (Groups A, B, C, D) according to the age class (2–12 m, 13–35 m, 3–6 years and 7–14 years) respectively, also each group were divided into four subgroups by induction dose (0.15, 0.2 mg/kg in 2–12 m age class; 0.2, 0.25 mg/kg in other three age classes), and mivacurium injection time (20 s, 40 s), totally 16 subgroups. Neuromuscular transmission was monitored with supramaximal train-of-four stimulation of the ulnar nerve. Radial artery blood (1 ml) was sampled to quantify plasma histamine concentrations before and 1, 4, and 7 min after mivacurium injection (P0, P1, P2 and P3).

Results

Five hundred sixty-two cases completed the study. There were no demographic differences within the four groups. The onset time of 0.2 mg/kg groups in 2–12 m aged patients were shorter than those of 0.15 mg/kg groups (189 ± 64 s vs. 220 ± 73 s, 181 ± 60 s vs. 213 ± 71 s, P <0.05), and the recovery times were no statistical differences. The T1 25% recovery time of 0.2 mg/kg in 3–6 years aged patients was shorter than that of 0.25 mg/kg group (693 ± 188 s vs. 800 ± 206 s, P <0.05). The onset and recovery times of mivacurium were not different in 13–35 m and 7–14 years aged patients. The plasma concentrations of histamine at P0, P1, P2 and P3 were not different within four groups.

Conclusions

The induction dose and injection time of mivacurium had mostly insignificant effects on onset and recovery times. The main exception to this was that in 2–12 m aged patients, increasing the dose of mivacurium from 0.15 to 0.2 mg/kg accelerated the onset time by about 30 s. Mivacurium produced no significant release of histamine in any age group at the doses studied.

Trial registration

ClinicalTrials.gov Identifier-NCT02117401, July 14, 2014. (Retrospectively registered)

Tracheal extubation in deeply anesthetized pediatric patients after tonsillectomy: a comparison of high-concentration sevoflurane alone and low-concentration sevoflurane in combination with dexmedetomidine pre-medication

BACKGROUND

Dexmedetomidine can facilitate a smooth extubation process and reduce the requirement of sevoflurane and emergence agitation when administrated perioperatively. We aimed to observe the extubation process and the recovery characteristics in pediatric patients undergoing tonsillectomy while anesthetized with either high-concentration sevoflurane alone or low-concentration sevoflurane combined with pre-medication of single dose of intravenous dexmedetomidine.

METHODS

Seventy-five patients (ASA I or II, aged 3-7 years) undergoing tonsillectomy were randomized into three equal groups: to receive intravenous saline (Group D0), dexmedetomidine 1 μg/kg (Group D1), or dexmedetomidine 2 μg/kg (Group D2) approximately 10 min before anesthesia. Before the end of surgery, sevoflurane were adjusted to 1.5 times, 1.0 time and 0.8 times the minimal effective concentration in groups D₀, D₁ and D₂, respectively. The sevoflurane concentration for each group was maintained for at least 10 min before the tracheal deep-extubation was performed. The extubation event, recovery characteristics and post-op respiratory complications were recorded.

RESULTS

All tracheal tubes in three groups were removed successfully during deep anesthesia. Nine patients in Group D₀, three patients in Group D₁, and two patients in Group D₂ required oral airway to maintain a patent airway after extubation. The frequency of oral airway usage in groups D₁ and D₂ were significantly lower than that in Group D₀. The percentages of patients with ED and the requirements of fentanyl in groups D₁ and D₂ were also significantly lower than those in Group D₀. The time from extubation to spontaneous eye opening in Group D₂ was longer than that in groups D₀ and D₁. The times of post-anesthesia care unit discharge in groups D₀ and D₂ were longer than that in Group D₁. No other respiratory complications and vomiting were observed.

CONCLUSION

A single dose of intravenous dexmedetomidine as pre-medication in combination with low-concentration sevoflurane at the end of surgery provided safe and smooth deep extubation condition and it also lowered the emergence agitation in sevoflurane-anaesthetized children undergoing tonsillectomy. Preoperative dexmedetomidine at 1 μg/kg did not prolong postoperative recovery time.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR): ChiCTR-IOR-16008423 , date of registration: 06 may 2016.