Correspondence
363
Splitting tubes We would like to report another possible cause of patient disconnection from the anaesthetic breathing system, this time associated with a possible manufacturing fault in equipment. While checking the connector inserted into the end of a Kendal Curity tracheal tube it was noticed that the tube was split at the end along the radiologically opaque line, causing the fitting to be loose. A second tube was prepared and although the fitting was now tight and the tube had not split, it was noted that the opaque line was stretching
(Fig. 1). We feel that this weakness in the tracheal tube is a manufacturing design or production fault and needs to be specifically looked for when using these particular tubes. Peterborough District Hospital, Peterborough PE3 6DE
M.B. SMITH J.D. W A m
A reply Thank you for the opportunity to reply. Drs Smith and Watts' communication related to a problem encountered with a small number of our 8.00 mm Curity cuffed tracheal tubes which occurred in October 1991. Immediate corrective action was taken at that time to improve product specifications and manufacturing controls, supported by the rapid implementation of a replacement programme for all 8.00 mm Curity tracheal tubes out in the market. In view of the time elapsed since the original complaints were dealt with, and the publication of Drs Smith and Watts' letter, we are natually concerned that this is not seen as a recurrence of the original problem. Director, Regulatory AflairslEurope, The Kendall Company ( U K ) Ltd, Basingstoke, Hampshire RG24 0 WG
Fig. 1.
J. LLOYDDAVID
Local anaesthesia for reduction of neonatal inguinal hernia Inguinal herniae are the most common reason for surgery in the neonatal period. An irreducible hernia in this age group poses a problem relating to analgesia. I wish to report a case using a technique not previously described. A 2-week-old male twin neonate was admitted to a general paediatric ward with a short history of right-sided scrotal swelling. Although he had been feeding well, he had vomited on one occasion. On examination, there was an inguinal hernia containing loops of bowel extending into the scrotum. This was irreducible and appeared to be tender with mild erythema of the scrotal skin. The child was distressed and there was a palpable impulse with each cry. It was felt that without muscle relaxation or analgesia, the hernia would remain unreduced, and my help was sought. A 0.125% solution of plain bupivicaine was prepared and 2.5 ml (3.125 mg) was infiltrated around the neck of the hernia using a 25 gauge needle. Within 5 min of this procedure, it became possible to reduce the hernia to less than half its original size using gentle manual pressure. This could be done without causing distress. Twelve hours later, the hernia was entirely reduced, and the child was discharged home to await elective surgery. The susceptibility to respiratory depression by opioids makes their administration to a neonate a problem. In a district general hospital, it may be difficult to provide adequate monitoring or ventilatory support for a child of
this age. The use of regional techniques provides an alternative and safer method for analgesia, so long as certain precautions are observed. Toxic effects from local anaesthetic agents are more likely in the neonate, because drug distribution differs from that of the older patient with alterations in body water and fewer protein binding sites [I]. Lower levels of alpha, acid glycoprotein result in increased free fraction of bupivicaine [2]. For these reasons it is important to restrict the maximum dose of local anaesthetic, especially if used in a vascular area. In this case, bupivacaine was chosen for its duration of action, but the dose given was limited to 1 mg.kg-'. Perhaps the adult dose of 2 mg.kg-' is too high? University Department of Anaesthesia. Shejield SlO 2RX
O.A. WILLIAMS
References [I] BESUNDER JB, REED MD, BLUMERJL. Principles of drug biodisposition in the neonate. A critical evaluation of the pharmacokinetic-pharmacodynamic interface. Clinical Pharmacokinetics 1988; 14 189-216. [2] MAZOITJX, DENSONDD, SAMIIK. Pharmacokinetics of bupivacaine following caudal anaesthesia in infants. Anesthesiology 1988; 68: 387-91.
Doxapram after general anaesthesia We were interested to read Drs Sarma and Fry's paper (Anaesthesia 1991; 46: 460-1) concerning the role of doxapram in the treatment of postoperative shivering. They state that 60-100 mg of doxapram were administered
to those patients who failed to stop shivering within 5 min of their initial treatment. The data they present d o not, however, identify the numbers of patients who required this additional treatment. Consequently we cannot identify the
364
Correspondence
number of patients in the doxapram treatment group, who took longer than 1 rnin to stop shivering, who also had this extra dose of doxapram. More importantly, we also cannot tell what proportion of the five patients in the placebo group who took longer than 1 min to stop shivering, went on to recieve doxapram prior to the cessation of shivering. Without further clarification we feel that the efficacy of doxapram in the treatment of postoperative shivering cannot exactly be determined. Northern General Hospital, Herries Road Shefield
I.J. BROOME G.H. MILLS
A reply
Thank you for giving me an opportunity to reply to Drs Broome and Mills. There appears to be some confusion regarding the data presented in Table 2 of the article. We should have specified that in Table 2, line 4, the seven patients in the doxapram group and the five in the placebo
group who took more than 1 min to stop shivering all did so within 5 min of initial treatment and hence did not require additional doxapram. As the results after injecting the initial drug were significant, we did not feel it was necessary to give details of patients who required additional doxapram and time taken to stop shivering after a known drug was given. Additional doxapram was given to 29 patients, of which 22 were from the placebo group; 16 of the placebo group patients stopped shivering within 1 min, one took nearly 15 rnin and five stopped shivering within 4 rnin of administering additional doxapram. Seven patients in the doxapram group required additional doxapram. Of these one stopped shivering within a min, five responded in 5 to 10 rnin and one took longer than 10 min. I hope this clarifies any doubts these authors may have regarding efficacy of doxapram in the treatment of postoperative shivering. North Tees General Hospital, Stockton-on- Tees, Cleveland TS19 8PE
V. SARMA
Insertion of interpleural catheters We congratulate Drs Marsh and McDonald on their modified technique for insertion of interpleural catheters (Anaesthesia 1991; 46: 889). However, we would like to point out that this method has been described previously [ l]!
Herzliya Medical Centre, Haifa, Israel
B. BEN-DAVID
Reference Vanderbilt University Hospital Nashville. Tennessee 37232-2125, USA
E.M. LEE
[I] BEN-DAVID B, LEEE. The falling column: a new technique for interpleural catheter placement. Anesthesia and Andgesia 1990; 71: 212.
363
Splitting tubes We would like to report another possible cause of patient disconnection from the anaesthetic breathing system, this time associated with a possible manufacturing fault in equipment. While checking the connector inserted into the end of a Kendal Curity tracheal tube it was noticed that the tube was split at the end along the radiologically opaque line, causing the fitting to be loose. A second tube was prepared and although the fitting was now tight and the tube had not split, it was noted that the opaque line was stretching
(Fig. 1). We feel that this weakness in the tracheal tube is a manufacturing design or production fault and needs to be specifically looked for when using these particular tubes. Peterborough District Hospital, Peterborough PE3 6DE
M.B. SMITH J.D. W A m
A reply Thank you for the opportunity to reply. Drs Smith and Watts' communication related to a problem encountered with a small number of our 8.00 mm Curity cuffed tracheal tubes which occurred in October 1991. Immediate corrective action was taken at that time to improve product specifications and manufacturing controls, supported by the rapid implementation of a replacement programme for all 8.00 mm Curity tracheal tubes out in the market. In view of the time elapsed since the original complaints were dealt with, and the publication of Drs Smith and Watts' letter, we are natually concerned that this is not seen as a recurrence of the original problem. Director, Regulatory AflairslEurope, The Kendall Company ( U K ) Ltd, Basingstoke, Hampshire RG24 0 WG
Fig. 1.
J. LLOYDDAVID
Local anaesthesia for reduction of neonatal inguinal hernia Inguinal herniae are the most common reason for surgery in the neonatal period. An irreducible hernia in this age group poses a problem relating to analgesia. I wish to report a case using a technique not previously described. A 2-week-old male twin neonate was admitted to a general paediatric ward with a short history of right-sided scrotal swelling. Although he had been feeding well, he had vomited on one occasion. On examination, there was an inguinal hernia containing loops of bowel extending into the scrotum. This was irreducible and appeared to be tender with mild erythema of the scrotal skin. The child was distressed and there was a palpable impulse with each cry. It was felt that without muscle relaxation or analgesia, the hernia would remain unreduced, and my help was sought. A 0.125% solution of plain bupivicaine was prepared and 2.5 ml (3.125 mg) was infiltrated around the neck of the hernia using a 25 gauge needle. Within 5 min of this procedure, it became possible to reduce the hernia to less than half its original size using gentle manual pressure. This could be done without causing distress. Twelve hours later, the hernia was entirely reduced, and the child was discharged home to await elective surgery. The susceptibility to respiratory depression by opioids makes their administration to a neonate a problem. In a district general hospital, it may be difficult to provide adequate monitoring or ventilatory support for a child of
this age. The use of regional techniques provides an alternative and safer method for analgesia, so long as certain precautions are observed. Toxic effects from local anaesthetic agents are more likely in the neonate, because drug distribution differs from that of the older patient with alterations in body water and fewer protein binding sites [I]. Lower levels of alpha, acid glycoprotein result in increased free fraction of bupivicaine [2]. For these reasons it is important to restrict the maximum dose of local anaesthetic, especially if used in a vascular area. In this case, bupivacaine was chosen for its duration of action, but the dose given was limited to 1 mg.kg-'. Perhaps the adult dose of 2 mg.kg-' is too high? University Department of Anaesthesia. Shejield SlO 2RX
O.A. WILLIAMS
References [I] BESUNDER JB, REED MD, BLUMERJL. Principles of drug biodisposition in the neonate. A critical evaluation of the pharmacokinetic-pharmacodynamic interface. Clinical Pharmacokinetics 1988; 14 189-216. [2] MAZOITJX, DENSONDD, SAMIIK. Pharmacokinetics of bupivacaine following caudal anaesthesia in infants. Anesthesiology 1988; 68: 387-91.
Doxapram after general anaesthesia We were interested to read Drs Sarma and Fry's paper (Anaesthesia 1991; 46: 460-1) concerning the role of doxapram in the treatment of postoperative shivering. They state that 60-100 mg of doxapram were administered
to those patients who failed to stop shivering within 5 min of their initial treatment. The data they present d o not, however, identify the numbers of patients who required this additional treatment. Consequently we cannot identify the
364
Correspondence
number of patients in the doxapram treatment group, who took longer than 1 rnin to stop shivering, who also had this extra dose of doxapram. More importantly, we also cannot tell what proportion of the five patients in the placebo group who took longer than 1 min to stop shivering, went on to recieve doxapram prior to the cessation of shivering. Without further clarification we feel that the efficacy of doxapram in the treatment of postoperative shivering cannot exactly be determined. Northern General Hospital, Herries Road Shefield
I.J. BROOME G.H. MILLS
A reply
Thank you for giving me an opportunity to reply to Drs Broome and Mills. There appears to be some confusion regarding the data presented in Table 2 of the article. We should have specified that in Table 2, line 4, the seven patients in the doxapram group and the five in the placebo
group who took more than 1 min to stop shivering all did so within 5 min of initial treatment and hence did not require additional doxapram. As the results after injecting the initial drug were significant, we did not feel it was necessary to give details of patients who required additional doxapram and time taken to stop shivering after a known drug was given. Additional doxapram was given to 29 patients, of which 22 were from the placebo group; 16 of the placebo group patients stopped shivering within 1 min, one took nearly 15 rnin and five stopped shivering within 4 rnin of administering additional doxapram. Seven patients in the doxapram group required additional doxapram. Of these one stopped shivering within a min, five responded in 5 to 10 rnin and one took longer than 10 min. I hope this clarifies any doubts these authors may have regarding efficacy of doxapram in the treatment of postoperative shivering. North Tees General Hospital, Stockton-on- Tees, Cleveland TS19 8PE
V. SARMA
Insertion of interpleural catheters We congratulate Drs Marsh and McDonald on their modified technique for insertion of interpleural catheters (Anaesthesia 1991; 46: 889). However, we would like to point out that this method has been described previously [ l]!
Herzliya Medical Centre, Haifa, Israel
B. BEN-DAVID
Reference Vanderbilt University Hospital Nashville. Tennessee 37232-2125, USA
E.M. LEE
[I] BEN-DAVID B, LEEE. The falling column: a new technique for interpleural catheter placement. Anesthesia and Andgesia 1990; 71: 212.
