The Effect of Test Dose Fentanyl on Predicting Postoperative Respiratory Depression in Patients with Continuous Intravenous Morphine Analgesia

Objective: To evaluate the effect of test dose fentanyl on predictingpostoperative analgesia and respiratory depression. Methods: Preoperatively the lowest pulseoximeter saturation (SpO_2) under room air breathing was measured after 2 μg/kg of fentanyl givenintravenously in 35 patients who were scheduled with continuous intravenous morphine analgesia (12μg·kg^(-1)·h^(-1)) postoperatively. Results: The test dose fentanyl resulted in respiratorydepression in 19 of 35 cases, while 8 (42.1%) of the 19 cases developed respiratory depressionpostoperatively. However in the rest 16 patients, no patient (0) developed respiratory depression (P< 0.01). The fentanyl-induced lowest SpO_2 significantly correlated with the lowest SpO_2postoperatively (P < 0.01). The analgesia effect in terms of verbal analogue scale was correlatedneither with the fentanyl-induced lowest SpO_2 nor with the lowest SpO_2 postoperatively (P > 0.05).Conclusion: The patient who was sensitive to fentanyl-induced respiratory depression would take ahigh risk to develop postoperative respiratory depression with intravenous morphine analgesia andthe patient with respiratory depression does not always go with satisfactory analgesia.

Acute respiratory depression resulting from ten milligram of oral morphine:an unusual case

Morphine belongs to opioid analgesics,which acts on the central nervous system.It can improve emotional responses such as anxiety,tension,and fear caused by pain and relieve it.Morphine had been widely used in the treatment of cancer-related pain.However,a series of opioid-associated adverse effects including opioid-induced respiratory depression were reported in clinical practice.Here,we reported a unique patient diagnosed with lung cancer,who underwent respiratory depression resulting from oral administration of ten milligram of morphine and was successfully resuscitated by naloxone.A literature review is then performed to analyze this rare condition.

Predictor of respiratory disturbances during gastric endoscopic submucosal dissection under deep sedation

BACKGROUND Sedation is commonly performed for the endoscopic submucosal dissection(ESD)of early gastric cancer.Severe hypoxemia occasionally occurs due to the respiratory depression during sedation.AIM To establish predictive models for respiratory depression during sedation for ESD.METHODS Thirty-five adult patients undergoing sedation using propofol and pentazocine for gastric ESDs participated in this prospective observational study.Preoperatively,a portable sleep monitor and STOP questionnaires,which are the established screening tools for sleep apnea syndrome,were utilized.Respiration during sedation was assessed by a standard polysomnography technique including the pulse oximeter,nasal pressure sensor,nasal thermistor sensor,and chest and abdominal respiratory motion sensors.The apnea-hypopnea index(AHI)was obtained using a preoperative portable sleep monitor and polysomnography during ESD.A predictive model for the AHI during sedation was developed using either the preoperative AHI or STOP questionnaire score.RESULTS All ESDs were completed successfully and without complications.Seventeen patients(49%)had a preoperative AHI greater than 5/h.The intraoperative AHI was significantly greater than the preoperative AHI(12.8±7.6 events/h vs 9.35±11.0 events/h,P=0.049).Among the potential predictive variables,age,body mass index,STOP questionnaire score,and preoperative AHI were significantly correlated with AHI during sedation.Multiple linear regression analysis determined either STOP questionnaire score or preoperative AHI as independent predictors for intraoperative AHI≥30/h(area under the curve[AUC]:0.707 and 0.833,respectively)and AHI between 15 and 30/h(AUC:0.761 and 0.778,respectively).CONCLUSION The cost-effective STOP questionnaire shows performance for predicting abnormal breathing during sedation for ESD that was equivalent to that of preoperative portable sleep monitoring.

Supraglottic jet oxygenation and ventilation(SJOV) for resuscitation of injured soldiers and people in war field

Dear Editor,Soldiers or people in battlefield settings are frequently injured with acute trauma, resulting in respiratory depression, hypoxia and associated morbidity and mortality. Traumatic brain injury(TBI) is with as much as 80%–90% of mild to moderate in combat casualties and contributed significantly to morbidity and mortality in battlefield settings. Correction of hypoxia at as capable as possible is expected to reduce or minimize the morbidity/mortality due to acute brain injury. An easy, quick and safe setup to promote oxygenation/ventilation of injured military personnel or peoples by non-medical personnel in battlefield settings immediately after acute injury before transfer to hospital is expected to reduce the morbidity/mortality due to injury mediated respiratory depression.

Neurotoxicity of prenatal alcohol exposure on medullary pre-B?tzinger complex neurons in neonatal rats

Prenatal alcohol exposure disrupts the development of normal fetal respiratory function, but whether it perturbs respiratory rhythmical discharge activity is unclear. Furthermore, it is unknown whether the 5-hydroxytryptamine 2A receptor（5-HT2AR） is involved in the effects of prenatal alcohol exposure. In the present study, pregnant female rats received drinking water containing alcohol at concentrations of 0%, 1%, 2%, 4%, 8% or 10%（v/v） throughout the gestation period. Slices of the medulla from 2-day-old neonatal rats were obtained to record respiratory rhythmical discharge activity. 5-HT2 AR protein and m RNA levels in the pre-B？tzinger complex of the respiratory center were measured by western blot analysis and quantitative RT-PCR, respectively. Compared with the 0% alcohol group, respiratory rhythmical discharge activity in medullary slices in the 4%, 8% and 10% alcohol groups was decreased, and the reduction was greatest in the 8% alcohol group. Respiratory rhythmical discharge activity in the 10% alcohol group was irregular. Thus, 8% was the most effective alcohol concentration at attenuating respiratory rhythmical discharge activity. These findings suggest that prenatal alcohol exposure attenuates respiratory rhythmical discharge activity in neonatal rats by downregulating 5-HT2 AR protein and m RNA levels.