General Anesthesia with Endotracheal Intubation for Cryotherapy for Retinopathy of Prematurity

Low Body Weight Predicted Bradycardia and Desaturation in Retinopathy of Prematurity Surgeries: A Retrospective Cohort Study

Background: As a leading cause of childhood blindness, the epidemic of retinopathy of prematurity (ROP) in China is characterized by advanced stage of ROP in more mature infants than those in the West. More advanced stage of disease necessitates more complicated surgical procedures and consequently exposure to general anesthesia. These ex-prematurely born infants are at risk of developing desaturation especially after surgery under general anesthesia. Physical status, anesthetic management and surgical profile are three main facets of perioperative setting and need to be investigated to identify useful predictors for perioperative adverse events in this population of fragile infants. Methods: In this retrospective cohort study, we enrolled all infants undergoing ROP surgeries at Peking University People's Hospital, Beijing, China from November 1, 2016 to October 31, 2017. Physical status, anesthesia and surgical management were analyzed by exploratory factor analysis and component matrix to explore risk factors for adverse events. Results: During the 12 months, 267 cases were included, among whom 61 infants underwent two surgeries required by their ophthalmological conditions. The median postconceptual age at the time of surgery was 46 (40, 53) weeks, and median body weight was 4.0 (3.0, 6.5) kg. None of the infants was dependent on caffeine, oxygen or ventilator before surgery. Bradycardia (29/267, 10.9%) and postoperative desaturation (34/267, 13.4%) were identified as major cardiac and respiratory adverse events. Preoperative atropine, intubation and bigger body weight would prevent patients suffering from bradycardia. Infants with a body weight less than 3.15 kg had a significantly higher chance of desaturation and neonatal intensive care unit admission after ROP surgeries than those who weighed more than 3.15 kg (27.8 vs. 5.1%, OR 5.46 (95% CI 2.66-11.21), P = 0.000). Conclusion: This study found that preoperative atropine and intubation would prevent bradycardia and low body weight was a predictor for both bradycardia and postoperative desaturation in preterm infants undergoing ROP surgeries.

Comparison of fentanyl and morphine in laser surgery for retinopathy of prematurity

PURPOSE

To compare complication rates of the analgesics fentanyl and morphine in preterm infants undergoing laser therapy for retinopathy of prematurity (ROP).

METHODS

In this observational study, the medical records of consecutive preterm neonates undergoing laser treatment of ROP from June 2007 through September 2010 were retrospectively reviewed. Because a fentanyl-based infusion protocol was initiated in November 2009, there was approximately the same number of treatment sessions with morphine and with fentanyl. In both groups, midazolam was used additionally on a case-by-case basis. Analgesia type, complications, and vital signs were documented at 5-minute intervals for all surgeries. The primary outcome was change in ventilation status. Secondary complications included change in temperature and incidence of apneic, bradycardic, and desaturation events.

RESULTS

A total of 35 patients were included, with 17 in the morphine group (mean gestational age, 24.8 weeks; mean birth weight, 661 g) and 18 in the fentanyl group (mean gestational age, 24.4 weeks; mean birth weight, 681 g). Overall worsening of ventilation status was noted in 29% of patients in the morphine group and 6% of patients in the fentanyl group (P = 0.08; 95% confidence interval, -2% to 48%). Temperature instability (outside of 36.5° to 37.4°C range) was noted in 6% of patients in the morphine group and no patients in the fentanyl group. Apneic events were 3.2 times more common and bradycardic events 1.5 times more common in the morphine group.

CONCLUSIONS

We found no difference in safety parameters for fentanyl infusion or morphine for analgesia in preterm infants undergoing ROP laser therapy in the neonatal intensive care unit setting. Although estimates of complication rates suggest that fentanyl may be safer, further study is needed to confirm this premise.

Avoiding endotracheal intubation of neonates undergoing laser surgery for retinopathy of prematurity

OBJECTIVE

Respiratory support of neonates during and following laser surgery for retinopathy of prematurity (ROP) is commonly accomplished using endotracheal intubation and mechanical ventilation. However, most patients undergoing ROP surgery have been weaned off mechanical ventilation days or weeks before the surgery. When they are electively re-intubated for ROP surgery, it can be difficult to extubate them postoperatively. One of the three level III neonatal intensive care units (NICUs) in the Intermountain Healthcare system initiated a program of using nasopharyngeal prongs, rather than endotracheal intubation, for respiratory support during ROP surgery.

METHODS

We performed an historic cohort analysis of all neonates undergoing ROP surgery during their NICU stay at the three level III NICU's between 1 January 2002 and 31 March 2006. Data collected included birth weight, gestational age at delivery and corrected gestational age at ROP surgery, whether or not they were intubated in the days immediately preceding the ROP surgery, whether or not they were electively intubated for the ROP surgery, the respiratory modality used during and the 3 days following ROP surgery, and all blood gas determinations and respiratory charges during this period.

RESULTS

Fifty-four patients underwent ROP surgery during this period. All 23 from NICUs 'A' and 'B' had endotracheal intubation for surgery, while in NICU 'C' 24 were managed using nasopharyngeal prongs. The birth weights of those intubated for surgery (661+/-180 g, mean+/-s.d.) were similar to those not intubated (732+/-180 g). Similarly, the gestational age at birth did not differ between those intubated for surgery (25.2+/-1.3 week) and those not (25.6+/-2.1 week). The day following surgery, 77% (23/30) of those who had been intubated for surgery remained intubated and on mechanical ventilation, whereas only one (4%) of those not intubated for surgery was intubated in the postoperative period (P<0.001). On day 3 following surgery, 50% (15/30) of those intubated for surgery remained intubated and on mechanical ventilation, whereas none of those not intubated for surgery were intubated (P<0.001). Management with nasopharyngeal prongs did not result in higher PCO(2)s, or lower pH values, during or after surgery. Respiratory charges for the 3 days following surgery were 1762+/-678 dollars (mean+/-s.d.)/patient among those intubated versus 357+/-352 dollars/patient for those managed with nasopharyngeal prongs (P<0.001).

CONCLUSIONS

Neonates undergoing laser surgery for ROP can often be supported intraoperatively and postoperatively using nasopharyngeal prongs, thus avoiding the need for endotracheal intubation.

Morphine analgesia as an alternative to general anaesthesia during laser treatment of retinopathy of prematurity

PURPOSE

To determine the feasibility and efficacy of morphine sedation/analgesia in the laser treatment of retinopathy of prematurity (ROP).

METHODS

A retrospective study was carried out on all infants who underwent laser treatment for ROP over a 7 year period. Morphine infusion commenced 6 hrs prior to treatment at a rate of 10 microg/kg/hr. This rate increased to 20 microg/kg/hr at the start of laser treatment. Subsequent infusion rate was titrated according to tolerance of the laser and cardio and respiratory system changes and evidence of infant distress (truncal and limb movements) up to a maximum rate of 40 microg/kg/hr. Following treatment, morphine was weaned over 6 hrs. Infant ventilation status was recorded prior to and during morphine infusion and during laser treatment. The incidences of adverse cardiac or respiratory events occurring during laser treatment were determined.

RESULTS

One hundred and nine infants treated from 1998 to 2005 were involved in the study. One hundred and thirty-six treatments were performed and mean gestational age at the time of treatment was 36 weeks. In 130 treatments, respiratory status remained stable and was not adversely affected. Infants were mechanically ventilated because of morphine-induced apnoea during three treatments, because of poor laser tolerance during two treatments and because of post-procedure apnoea in one case. In 65 treatments, minor alterations in oxygen saturation (< 90%), bradycardia or tachycardia occurred.

CONCLUSION

This study demonstrates that morphine analgesia can be used as an alternative to general anaesthesia.