Surgery in very low birthweight infants

Biologic markers of pain in the vulnerable infant

Detecting and quantifying pain in infants and young children is a complex task because young children cannot communicate this subjective phenomenon. In the 1950s, it was postulated that there might be "wound hormones" produced in injured tissues that activated the pituitary-adrenal axis. Research in adults demonstrated that plasma levels of different hormones, including corticosteroids, cathecholamines, growth hormone, and insulin, changed in response to emotionally and physically stressful stimuli. Stress response is the term given to those hormonal and metabolic changes that follow injury or trauma, but the debate as to whether increased stress response is a sign of pain or whether decreased stress response is a sign of diminished pain has not been resolved yet. Following the study of systemic response to surgery, the ability of anesthetic agents to substantially attenuate intraoperative and postoperative stress response has been reported. In newborns, a strong correlation between preoperative stress and postoperative complication rate was found. The full extent of the vulnerable infant's pain is still poorly understood, but further research of known biologic markers and newly discovered ones could promote our understanding of the pain response and increase our ability to prevent undesirable outcome.

Regional anaesthesia decreases the need for postoperative mechanical ventilation in very low birth weight infants undergoing herniorrhaphy

BACKGROUND

We were interested to know whether regional anaesthesia allowed improved respiratory function postoperatively in very low birth weight babies.

METHODS

We performed a retrospective study to examine the association between regional anaesthesia and postoperative ventilation after herniorrhaphy in very low birth weight infants. Thirty-four prematurely born infants underwent herniorrhaphy from 1995 to 1997 at St Louis Children Hospital. Eighteen patients had general anaesthesia, 16 had regional anaesthesia. The mean gestational age was 26 weeks, mean postconceptual age at surgery was 38 weeks, mean birth weight was 860 g.

RESULTS

There was significant difference in postoperative ventilation support requirements between the two study groups (7/18 versus 1/16, P < 0.05).

CONCLUSIONS

Regional anaesthesia decreases the need for postoperative ventilatory support requirements in very low birth weight infants undergoing herniorrhaphy.

Ligation of a patent ductus arteriosus under fentanyl anesthesia improves protein metabolism in premature neonates

BACKGROUND/PURPOSE

Although surgical ligation effectively reverses the cardiopulmonary failure associated with patent ductus arteriosus (PDA), previous findings have suggested that such surgery itself elicits a catabolic response in premature neonates. Therefore, the authors sought to quantitatively assess whether PDA ligation under fentanyl anesthesia aggravated or improved the protein metabolism of premature neonates.

METHODS

Seven ventilated, premature neonates (birth weight 815 +/- 69 g) underwent PDA ligation with standardized fentanyl anesthesia (15 microg/kg) on day-of-life 8.4 +/- 1.2 and were studied immediately pre- and 16 to 24 hours postoperatively while receiving continuous total parenteral nutrition (TPN). Whole-body protein kinetics were calculated using intravenous 1-[13C]leucine, and skeletal muscle protein breakdown was measured from the urinary 3-methylhistidine to creatinine ratio (MH:Cr).

RESULTS

Whole-body protein breakdown (10.9 +/- 1.2 v8.9 +/- 0.8 g/kg/d, P < .05), turnover (17.4 +/- 1.2 v 15.4 +/- 0.8 g/kg/d, P< .05), and MH:Cr (1.95 +/- 0.20 v 1.71 +/- 0.16 micromol:mg, P< .05) decreased significantly after operation. This resulted in a 60% improvement in protein balance (1.6 +/- 0.8 v 2.6 +/- 0.6 g/kg/d, P = 0.08) postoperatively.

CONCLUSIONS

Because of decreased whole-body protein breakdown, whole-body protein turnover, skeletal muscle protein breakdown, and increased protein accrual, surgical PDA ligation under fentanyl anesthesia promptly improves the protein metabolism of premature neonates enduring the stress of a PDA.

The neuroanatomy, neurophysiology, and neurochemistry of pain, stress, and analgesia in newborns and children

Beginning with a brief description of mature anatomic pathways and neurotransmitters in the "pain system," this article details their development in the human fetus, neonate, and child. Special emphasis is given to the basic mechanisms and physiologic effects of opioid analgesia. The clinical implications of these data are described, particularly with regard to the maintenance of cardiovascular stability and hormonal-metabolic homeostasis in newborns and children undergoing surgery or other forms of stress.

Survival of the weakest. Improving prospects for surgery in infants of birthweight less than 1,200 grams

Over a six-year period seventeen infants of birthweight less than 1,200 grams (including nine of birthweight less than 1,000 grams) underwent major gastrointestinal surgery. Fourteen of the seventeen (82%) survived, a higher rate than previously reported. Nine infants had necrotising enterocolitis, three had oesophageal atresia and five had other types of intestinal obstruction. Six infants who were unfit to be transferred to the operating theatre underwent surgery on the neonatal unit: of these, four survived. We feel the outlook is optimised by conservative surgical intervention and by maximal medical support with intensive care monitoring, post-operative mechanical ventilation and intravenous alimentation. Survival after surgery is now very much the rule in the extremely low birthweight infant, even in those who are too sick to be transferred to the operating theatre.

Randomised trial of fentanyl anaesthesia in preterm babies undergoing surgery: effects on the stress response

In a randomised controlled trial, preterm babies undergoing ligation of a patent ductus arteriosus were given nitrous oxide and d-tubocurarine, with (n = 8) or without (n = 8) the addition of fentanyl (10 micrograms/kg intravenously) to the anaesthetic regimen. Major hormonal responses to surgery, as indicated by changes in plasma adrenaline, noradrenaline, glucagon, aldosterone, corticosterone, 11-deoxycorticosterone, and 11-deoxycortisol levels, in the insulin/glucagon, molar ratio, and in blood glucose, lactate, and pyruvate concentrations were significantly greater in the non-fentanyl than in the fentanyl group. The urinary 3-methylhistidine/creatinine ratios were significantly greater in the non-fentanyl group on the second and third postoperative days. Compared with the fentanyl group, the non-fentanyl group had circulatory and metabolic complications postoperatively. The findings indicate that preterm babies mount a substantial stress response to surgery under anaesthesia with nitrous oxide and curare and that prevention of this response by fentanyl anaesthesia may be associated with an improved postoperative outcome.

Randomised trial of fentanyl anaesthesia in preterm babies undergoing surgery: effects on the stress response

In a randomised controlled trial, preterm babies undergoing ligation of a patent ductus arteriosus were given nitrous oxide and d-tubocurarine, with (n = 8) or without (n = 8) the addition of fentanyl (10 micrograms/kg intravenously) to the anaesthetic regimen. Major hormonal responses to surgery, as indicated by changes in plasma adrenaline, noradrenaline, glucagon, aldosterone, corticosterone, 11-deoxycorticosterone, and 11-deoxycortisol levels, in the insulin/glucagon, molar ratio, and in blood glucose, lactate, and pyruvate concentrations were significantly greater in the non-fentanyl than in the fentanyl group. The urinary 3-methylhistidine/creatinine ratios were significantly greater in the non-fentanyl group on the second and third postoperative days. Compared with the fentanyl group, the non-fentanyl group had circulatory and metabolic complications postoperatively. The findings indicate that preterm babies mount a substantial stress response to surgery under anaesthesia with nitrous oxide and curare and that prevention of this response by fentanyl anaesthesia may be associated with an improved postoperative outcome.